# Tires that fit 622x18 Wheel



## cybrslug

Hi all long time rider first time poster. I have a Specialized Globe Sport Disk that came with 622x18 Alex Wheels running 700c x 32 Specialized Nimbus tires. Now Those tires were pretty fast, and certainly held their own in many terrains conditions, but I wanted to increase my speed and reduce rolling resistance as it is my primary commuter and I average about 32 miles per day 5 days a week. 

I purchased some Hutchinson Fusion Ultra 700x23's, but after several different forums, and the infamous Sheldon Brown tire/wheel size graph I opted not to install the 700x23's and installed Specialized All Weather Armadillo 700x25's. The Hutchinson Fusion Ultra's showed up in the mail, and I opened the box and once again felt that those were the tires I want to ride on, not that the Armadillos are bad. So here I am rather then continuing to read multiple forum post on similar topics, I am post to the masses for input.

Your wisdom and help are much appreciated


----------



## Spunout

Go ride.


----------



## cybrslug

Spunout said:


> Go ride.


Spunout,

Thnx for the quick reply to my post, but input was more of what I am looking for.


----------



## Gevorg

My wheels have rim width 20 mm i.e.it is 622x20 and I have 700x23 tires on them if that helps.
I do not think you will have issue with the same tire on 622x18 rim, however you may find installation a little bit harder.


----------



## Kerry Irons

*Repeating the question*



cybrslug said:


> Hi all long time rider first time poster. I have a Specialized Globe Sport Disk that came with 622x18 Alex Wheels running 700c x 32 Specialized Nimbus tires. Now Those tires were pretty fast, and certainly held their own in many terrains conditions, but I wanted to increase my speed and reduce rolling resistance as it is my primary commuter and I average about 32 miles per day 5 days a week.
> 
> I purchased some Hutchinson Fusion Ultra 700x23's, but after several different forums, and the infamous Sheldon Brown tire/wheel size graph I opted not to install the 700x23's and installed Specialized All Weather Armadillo 700x25's. The Hutchinson Fusion Ultra's showed up in the mail, and I opened the box and once again felt that those were the tires I want to ride on, not that the Armadillos are bad. So here I am rather then continuing to read multiple forum post on similar topics, I am post to the masses for input.
> 
> Your wisdom and help are much appreciated


So, it's not completely clear what your question is. 

To expand on Spunout's advice, you can ride the Hutchinsons or the Armadillos, or whatever else you want. Tires wear out, so if one of these tires is not to your liking, you can replace it with something else that you think you might like better. The Hutchinsons will have a better ride than the Armadillos, but will not be as durable. You get to choose.


----------



## cybrslug

*Recap*

Sorry I was not clear in my initial post. the issue is with size. my Alex wheel is 622x18, but seems everyone I speak to, and the Sheldon Brown graph seem to indicate that going below a 25mm tire is not recommended for the width of my wheel. Actually the Sheldon brown graph does not recommend going below 28mm, but I believe it errs on the side of caution. Again, I am sorry I left my sizing issue out of the body of the post.


----------



## Spunout

You have no problem. Mount what you want, you've misread SB. Everyone else in the world uses 20-35mm tires on 18-21mm rims.


----------



## jalind

*Very OLD Thread - but SAFETY Issue!*



Spunout said:


> You have no problem. Mount what you want, you've misread SB. Everyone else in the world uses 20-35mm tires on 18-21mm rims.


This is bogus. A very, very old thread but there are safety issues with the horribly incorrect advice given here by guys shooting from the hip not knowing what they're talking about!

The OP asked about tire sizes for a rim with ETRTO dimensions of 622x18. The 18 is NOT the outside rim width, it's the INSIDE rim width (in mm) between the clincher hooks! The ETRTO 32-622 (aka 700x32C) tires the OP originally had on those rims are roughly in the middle of the tire width range for a 622x18 rim. The narrowest tire . . . by ETRTO dimensions . . . that can be safely used on that rim is a 28mm, one size narrower than the 32mm (32-622, or 700x32) that was on the rim. Going to a 25mm has a definite risk and 23mm is decidedly too narrow. Put too narrow a tire on a rim and you will roll the bead out of the rim's clincher hooks in hard cornering. For an ETRTO 622x18 rim, go no narrower than a 28-622 (aka 700x28c) tire!

As a reference point, the heavy steel touring bike with the Bontrager rims isn't my only bike. I have a carbon road racing bike and a track bike. The rims on both wheel sets for the road bike are Shimano, and they're ETRTO 622x15 which can go as narrow as 23mm tires and I use 23-622 tires on them. I'm not certain what the track bike has as the labels were completely removed from its rims long ago, but they're no wider than 622x15 and may be 622x13 for even narrower tires although I put 23-622 tires on them as well. I'd have to dismount a tire to measure the rim between the clincher hooks and I'm not about to do that for this thread. Note that Sheldon Brown's chart agrees with Continental's tire size and rim size chart for the narrowest allowable tire for each rim width.

The OP wanted a "faster" tire, and hence was looking for narrower. That's only part of the equation. Certainly 28mm wide tire has the potential to be faster, provided it's also rated for a high inflation pressure. A low inflation pressure tire with tread designed for off-road cyclo-cross would not be a wise choice as the combination of tire weight, a tread, and lower pressure would increase rolling resistance. A smooth pure road tire with high pressure, like a Continental Gatorskin foldup (lighter than the wire bead) would be a faster tire. So the combination of getting lower rolling resistance is a combination of tire weight, zero or very nearly zero tread, narrower width to 28mm, and high inflation pressure.

I found this thread as I was Googling for a chart that would show what tire widths could be used on the Bontrager 622x18 rims I have on a touring bike (that came with 32mm width tires). The OP did NOT misread Sheldon Brown's chart although it is conservative on how wide you can go, but NOT how narrow. FWIW, too wide a tire has handling issues because it bulges out from the rim so much causing sloppy handling and is hard on the rim walls because of the higher outward (lateral) pressure the tire bead puts on them.

Again, a very old thread, and I wouldn't have resurrected it except that Google finds it readily and it's laden with BAD information that could cause catastrophic wheel failure on the road if someone puts too narrow a tire on a rim . . . with a tire suddenly rolling off of or blowing off of the rim.

John


----------



## cxwrench

I guess the reason it's been dead for 6 years is the OP mounted a 23mm tire and was killed in a fiery wreck as soon as he started riding his bike, thus not being able to reply that that tire was indeed wayyyyyy to narrow for his rim. This is indeed a very important and regularly discussed subject.

ETA: I build wheels w/ HED Belgium + rims and mount 25mm tires all the time. HED recommends 22mm+, so 23mm tires are actually fine on those rims. Guess what the internal width is?

That would be 20.6mm. Care to change your advice?


----------



## ergott

jalind said:


> T
> I found this thread as I was Googling for a chart that would show what tire widths could be used on the Bontrager 622x18 rims I have on a touring bike (that came with 32mm width tires). The OP did NOT misread Sheldon Brown's chart although it is conservative on how wide you can go, but NOT how narrow. FWIW, too wide a tire has handling issues because it bulges out from the rim so much causing sloppy handling and is hard on the rim walls because of the higher outward (lateral) pressure the tire bead puts on them.
> 
> Again, a very old thread, and I wouldn't have resurrected it except that Google finds it readily and it's laden with BAD information that could cause catastrophic wheel failure on the road if someone puts too narrow a tire on a rim . . . with a tire suddenly rolling off of or blowing off of the rim.
> 
> John


I'm curious what your personal experience with this is? Several major companies use internal widths of 17-18mm (and more) and people aren't dying when they use 23-25mm tires.

CX's example is only one of many.


----------



## Jwiffle

jalind said:


> This is bogus. A very, very old thread but there are safety issues with the horribly incorrect advice given here by guys shooting from the hip not knowing what they're talking about!
> 
> The OP asked about tire sizes for a rim with ETRTO dimensions of 622x18. The 18 is NOT the outside rim width, it's the INSIDE rim width (in mm) between the clincher hooks! The ETRTO 32-622 (aka 700x32C) tires the OP originally had on those rims are roughly in the middle of the tire width range for a 622x18 rim. The narrowest tire . . . by ETRTO dimensions . . . that can be safely used on that rim is a 28mm, one size narrower than the 32mm (32-622, or 700x32) that was on the rim. Going to a 25mm has a definite risk and 23mm is decidedly too narrow. Put too narrow a tire on a rim and you will roll the bead out of the rim's clincher hooks in hard cornering. For an ETRTO 622x18 rim, go no narrower than a 28-622 (aka 700x28c) tire!
> 
> As a reference point, the heavy steel touring bike with the Bontrager rims isn't my only bike. I have a carbon road racing bike and a track bike. The rims on both wheel sets for the road bike are Shimano, and they're ETRTO 622x15 which can go as narrow as 23mm tires and I use 23-622 tires on them. I'm not certain what the track bike has as the labels were completely removed from its rims long ago, but they're no wider than 622x15 and may be 622x13 for even narrower tires although I put 23-622 tires on them as well. I'd have to dismount a tire to measure the rim between the clincher hooks and I'm not about to do that for this thread. Note that Sheldon Brown's chart agrees with Continental's tire size and rim size chart for the narrowest allowable tire for each rim width.
> 
> The OP wanted a "faster" tire, and hence was looking for narrower. That's only part of the equation. Certainly 28mm wide tire has the potential to be faster, provided it's also rated for a high inflation pressure. A low inflation pressure tire with tread designed for off-road cyclo-cross would not be a wise choice as the combination of tire weight, a tread, and lower pressure would increase rolling resistance. A smooth pure road tire with high pressure, like a Continental Gatorskin foldup (lighter than the wire bead) would be a faster tire. So the combination of getting lower rolling resistance is a combination of tire weight, zero or very nearly zero tread, narrower width to 28mm, and high inflation pressure.
> 
> I found this thread as I was Googling for a chart that would show what tire widths could be used on the Bontrager 622x18 rims I have on a touring bike (that came with 32mm width tires). The OP did NOT misread Sheldon Brown's chart although it is conservative on how wide you can go, but NOT how narrow. FWIW, too wide a tire has handling issues because it bulges out from the rim so much causing sloppy handling and is hard on the rim walls because of the higher outward (lateral) pressure the tire bead puts on them.
> 
> Again, a very old thread, and I wouldn't have resurrected it except that Google finds it readily and it's laden with BAD information that could cause catastrophic wheel failure on the road if someone puts too narrow a tire on a rim . . . with a tire suddenly rolling off of or blowing off of the rim.
> 
> John


Seriously? You dredge up an old thread to spread your fear-mongering?

23mm tires would be fine, even if not "ideal." And for that matter, the trend for several years now has been to run wider rims, even with 23s and 25s, because the ride has been found to be better, both in comfort and aerodynamics. And 23s are not routinely blowing off the 20mm internal width rims, much less the 18s.


----------



## Lombard

cxwrench said:


> I guess the reason it's been dead for 6 years is the OP mounted a 23mm tire and was killed in a fiery wreck as soon as he started riding his bike, thus not being able to reply that that tire was indeed wayyyyyy to narrow for his rim. This is indeed a very important and regularly discussed subject.
> 
> ETA: I build wheels w/ HED Belgium + rims and mount 25mm tires all the time. HED recommends 22mm+, so 23mm tires are actually fine on those rims. Guess what the internal width is?
> 
> That would be 20.6mm. Care to change your advice?





ergott said:


> I'm curious what your personal experience with this is? Several major companies use internal widths of 17-18mm (and more) and people aren't dying when they use 23-25mm tires.
> 
> CX's example is only one of many.





Jwiffle said:


> Seriously? You dredge up an old thread to spread your fear-mongering?
> 
> 23mm tires would be fine, even if not "ideal." And for that matter, the trend for several years now has been to run wider rims, even with 23s and 25s, because the ride has been found to be better, both in comfort and aerodynamics. And 23s are not routinely blowing off the 20mm internal width rims, much less the 18s.



Some interesting points, if not confusing. Right now, I run 28c tires on 622x15 rims. What I would like to know is:

1) Are there any non-custom road wheels in production today that AREN'T 622x15? That is all I have found unless I want to go custom or legacy.

2) 622x15 is the inside dimension of the rim. For that size, the outside dimension is usually around 20.8mm. To confuse things more, different brands use one or the other method of measuring.

3) Would there be any significant handling or other advantages for me to go to a wider rim since I like to use 28c tires? Unless I am mistaken, I would have to go with a custom build.

4) While the "thread dredger" may be alarmist to say the least, what is your take on Sheldon Brown's table?

Tire Sizing Systems 

There must be something to this. Possibly old school train of thought?


----------



## Blue CheeseHead

Hed Belgium Plus rims have a 21mm distance between bead hooks. I run a 23mm tire and have yet to die...or even have a tire failure.

The premise that a 23mm tire would be too narrow on a 18mm rim is simply wrong. As an engineer, I suppose I could draw a force diagram to prove it, but will save my time.


----------



## Blue CheeseHead

Lombard said:


> Some interesting points, if not confusing. Right now, I run 28c tires on 622x15 rims. What I would like to know is:
> 
> 1) Are there any non-custom road wheels in production today that AREN'T 622x15? That is all I have found unless I want to go custom or legacy.
> 
> 2) 622x15 is the inside dimension of the rim. For that size, the outside dimension is usually around 20.8mm. To confuse things more, different brands use one or the other method of measuring.
> 
> 3) Would there be any significant handling or other advantages for me to go to a wider rim since I like to use 28c tires? Unless I am mistaken, I would have to go with a custom build.
> 
> 4) While the "thread dredger" may be alarmist to say the least, what is your take on Sheldon Brown's table?
> 
> Tire Sizing Systems
> 
> There must be something to this. Possibly old school train of thought?


I am not sure where you get that any non-custom wheel is 622x15. Hed Ardennes are 17.8mm, Ardennes plus are 21mm. Both are stock wheels. Bontrager Race Lites are 17.5mm.

15mm wide rims are fading away in favor of wider rims that offer BETTER handling due to reducing the light bulb effect created by installing a wider tire on a narrow rim.

If you were to change to a 21mm wide rim you would find your 28mm tires would have an installed cross section of ~30mm


----------



## ergott

Zipp 404 is 17.25mm. 

Enve Smart is 18.5mm front and 17mm rear. Recommended tire size for them is 23-25mm

One of the newer Mavic Ksyriums (Elite ?) is 17mm.


----------



## Lombard

Blue CheeseHead said:


> I am not sure where you get that any non-custom wheel is 622x15. Hed Ardennes are 17.8mm, Ardennes plus are 21mm. Both are stock wheels. Bontrager Race Lites are 17.5mm.
> 
> 15mm wide rims are fading away in favor of wider rims that offer BETTER handling due to reducing the light bulb effect created by installing a wider tire on a narrow rim.
> 
> If you were to change to a 21mm wide rim you would find your 28mm tires would have an installed cross section of ~30mm



Haven't heard of Hed. I guess I need to get around more, eh? I don't think I would ever buy Bontrager wheels again. Does Shimano or Mavic make any wider road rims?


----------



## Orfitinho

DT Swiss newer wheels/rims are wider then 622x15. 

DT also has published recommendations of tire widths for different rim widths. 
https://www.dtswiss.com/resources/tech-pdf/tire_pressure_dimension.pdf
According to this, a 23 mm tire can be used with rims of 19.9 mm inner width (wich is about 25 mm outer width). 

This is quite in contrast to the current ETRTO (European Tyre and Rim Technical Organisation) recommendations wich require at least 28 mm tires for rims of 19 mm inner width.
The current ETRTO recommandations are listed in page 7 of this pdf. 
http://www.skeppshult.se/media/42824/TechInfo2-GB.pdf

I have asked Schwalbe and Continental about their opinion but both told me to follow ETRTO. They did not anwser my question about the possible risks I would take if using smaller tires with modern rims, and wether the ETRTO is expected to update the recommendations soon.

I for myself follow the DT-Swiss recommendations, not ETRTO.


----------



## jalind

Lombard said:


> Some interesting points, if not confusing. Right now, I run 28c tires on 622x15 rims. What I would like to know is:
> 
> 1) Are there any non-custom road wheels in production today that AREN'T 622x15? That is all I have found unless I want to go custom or legacy.
> 
> 2) 622x15 is the inside dimension of the rim. For that size, the outside dimension is usually around 20.8mm. To confuse things more, different brands use one or the other method of measuring.
> 
> 3) Would there be any significant handling or other advantages for me to go to a wider rim since I like to use 28c tires? Unless I am mistaken, I would have to go with a custom build.
> 
> 4) While the "thread dredger" may be alarmist to say the least, what is your take on Sheldon Brown's table?
> 
> Tire Sizing Systems
> 
> There must be something to this. Possibly old school train of thought?


Sheldon's table is spot on at the narrowest tire size for each rim size (internal) width, but is conservative at the widest tire size end. It's taken from ISO 5775-1 which evolved from the ETRTO (European Tire and Rim Technical Organisation) standards for clincher tires and the hook/crochet or (very old style) straight sided rims and the tire sizes that can be safely used on each size rim.

The ETRTO (and now ISO 5775-1:2014) grew out of the bike tire and rim industry fudging numbers and dimensions during the 1970's and 1980's to market the "lightest" tire and rim of a specific size. The ETRTO was created and stipulated very specific dimension measurement methods and requirements to make the manufacturers honest again, and to clearly communicate which tire widths were safe to use for a given rim width. You will find your rims and tires marked with the ISO 5775 dimensions, albeit usually in the fine print. I've got Shimano rims on which those label are so small I had to use a magnifier to read them. The 622mm is the rim Bead Seat Diameter (BSD) which can be considered the rim diameter at about the edge of the rim tape, a few millimeters below the hook. And yes, the other dimension is the internal width between the hooks. (Old straight side rims are a different matter.)

Rim manufacturers advertise primarily rim weight, outer depth and the outer width as buyers are obsessed with every last gram of weight and how "aero" the rims will be with their tires. When it comes to safely matching tires to rims, these outer dimensions don't matter one iota. It's the inside Bead Seat Diameter and internal hook width between the hooks that matters. One must dig, sometimes quite extensively through all the technical data fine print for some rim manufacturers to find the ETRTO / ISO-5775 rim dimensions.

According to ISO 5775-1:2014, the narrowest allowable tire size for the very common road bike 622x15 rim is a 23-622 (700c x 23 using the old French tire sizes). The widest tire allowable on the same rim is a 32-622 (aka 700c x 32), although you would need to see if such a wide tire would fit through the brake calipers and between the forks and chainstays. Thus, you can use a 28-622 on that rim.

Thus, it's not "old school" train of thought, but the current ISO standard for rim sizes and the appropriate tire sizes that can be used on them safely. Regarding another poster who claims to be building wheels well outside of this standard, I would not want to be the one trying to defend myself against a product liability injury claim for a wheel build (tire and rim) that did not comply with the current ISO 5775 (the 2014 version). The attorneys would have a field day over non-compliance with an international standard that was established specifically to provide for safely matching tires and rims by their sizes.

You can see a lengthy discussion of ISO 5775, including the current table of tire sizes allowed for each rim size in Wikipedia (it beats paying about $300 for a copy of the ISO standard):
https://en.wikipedia.org/wiki/ISO_5775

ISO 5775 was revised in 2006 to allow some wider tire sizes on some of the wider rim sizes, but there was no change at the narrowest tires allowed for the various rim sizes. Several tire manufacturers have similar tables of the allowable rim sizes that can be used with their various tire sizes, and they quite amazingly match the ISO 5775 table.

John


----------



## cxwrench

jalind said:


> Sheldon's table is spot on at the narrowest tire size for each rim size (internal) width, but is conservative at the widest tire size end. It's taken from ISO 5775-1 which evolved from the ETRTO (European Tire and Rim Technical Organisation) standards for clincher tires and the hook/crochet or (very old style) straight sided rims and the tire sizes that can be safely used on each size rim.
> 
> The ETRTO (and now ISO 5775-1:2014) grew out of the bike tire and rim industry fudging numbers and dimensions during the 1970's and 1980's to market the "lightest" tire and rim of a specific size. The ETRTO was created and stipulated very specific dimension measurement methods and requirements to make the manufacturers honest again, and to clearly communicate which tire widths were safe to use for a given rim width. You will find your rims and tires marked with the ISO 5775 dimensions, albeit usually in the fine print. I've got Shimano rims on which those label are so small I had to use a magnifier to read them. The 622mm is the rim Bead Seat Diameter (BSD) which can be considered the rim diameter at about the edge of the rim tape, a few millimeters below the hook. And yes, the other dimension is the internal width between the hooks. (Old straight side rims are a different matter.)
> 
> Rim manufacturers advertise primarily rim weight, outer depth and the outer width as buyers are obsessed with every last gram of weight and how "aero" the rims will be with their tires. When it comes to safely matching tires to rims, these outer dimensions don't matter one iota. It's the inside Bead Seat Diameter and internal hook width between the hooks that matters. One must dig, sometimes quite extensively through all the technical data fine print for some rim manufacturers to find the ETRTO / ISO-5775 rim dimensions.
> 
> According to ISO 5775-1:2014, the narrowest allowable tire size for the very common road bike 622x15 rim is a 23-622 (700c x 23 using the old French tire sizes). The widest tire allowable on the same rim is a 32-622 (aka 700c x 32), although you would need to see if such a wide tire would fit through the brake calipers and between the forks and chainstays. Thus, you can use a 28-622 on that rim.
> 
> Thus, it's not "old school" train of thought, but the current ISO standard for rim sizes and the appropriate tire sizes that can be used on them safely. Regarding another poster who claims to be building wheels well outside of this standard, I would not want to be the one trying to defend myself against a product liability injury claim for a wheel build (tire and rim) that did not comply with the current ISO 5775 (the 2014 version). The attorneys would have a field day over non-compliance with an international standard that was established specifically to provide for safely matching tires and rims by their sizes.
> 
> You can see a lengthy discussion of ISO 5775, including the current table of tire sizes allowed for each rim size in Wikipedia (it beats paying about $300 for a copy of the ISO standard):
> https://en.wikipedia.org/wiki/ISO_5775
> 
> ISO 5775 was revised in 2006 to allow some wider tire sizes on some of the wider rim sizes, but there was no change at the narrowest tires allowed for the various rim sizes. Several tire manufacturers have similar tables of the allowable rim sizes that can be used with their various tire sizes, and they quite amazingly match the ISO 5775 table.
> 
> John


You don't get out of the basement much do you? If any catastrophic accidents and fiery deaths were going to happen due to people mounting tires that were too narrow for their rims, they'd have definitely happened by now since so many people arrogantly flaunt the ERTO guidelines. I'm not worried in the least about any possible consequences as whatever I do is within the recommendations of the manufacturer. Have you actually even heard of a tire coming off a rim because of this? Ever? It's great that you're so passionate and thorough about this, but maybe you should find a truly worthy cause to get all excited about.


----------



## deviousalex

cxwrench said:


> I guess the reason it's been dead for 6 years is the OP mounted a 23mm tire and was killed in a fiery wreck as soon as he started riding his bike, thus not being able to reply that that tire was indeed wayyyyyy to narrow for his rim. This is indeed a very important and regularly discussed subject.
> 
> ETA: I build wheels w/ HED Belgium + rims and mount 25mm tires all the time. HED recommends 22mm+, so 23mm tires are actually fine on those rims. Guess what the internal width is?
> 
> That would be 20.6mm. Care to change your advice?


I'd give you rep but this thing won't let me!

@jalind - I run Michelin Lithion 2s at 23mm on Kinlin XR22T rims that are 19mm internal width. They measure 26mm at 95psi. I have yet to die a firey death from the tire coming off the rim.


----------



## Lombard

Interesting food for thought here. It appears the ETRTO guidelines err on the side of caution. Sort of the same way there is a minimum and maximum recommended PSI on a tire, but one can safely go either way to some degree.

This discussion brings up another point. Is there really a great advantage beyond those that are racers to wider rims ex: 622x19 rims with 25c tires (effectively making a 28c tire) vs. 622x15 rims with 28c tires. For the rest of us endurance type riders, is it just 6 of one and half a dozen of the other?


----------



## cxwrench

Anytime you can push the beads of a tire outwards making the base of the tire wider you're going to get a tire that is more stable at lower pressures than w/ a narrow rim/base. The tire shape will be more of a half circle than a light bulb. Make sense?


----------



## Lombard

cxwrench said:


> Anytime you can push the beads of a tire outwards making the base of the tire wider you're going to get a tire that is more stable at lower pressures than w/ a narrow rim/base. The tire shape will be more of a half circle than a light bulb. Make sense?



Your point is well taken. But will_I_notice the difference? Maybe I should take my generic Weinmann Zac 19 wheels off my hybrid, put a pair of 25c tires and mount them on my road bike to find out. Though that might not be a fair comparison.


----------



## cxwrench

Lombard said:


> Your point is well taken. But will_I_notice the difference? Maybe I should take my generic Weinmann Zac 19 wheels off my hybrid, put a pair of 25c tires and mount them on my road bike to find out. Though that might not be a fair comparison.


Depends. How much do you weight and what size/pressure are you using now?


----------



## dcgriz

Maybe, maybe not. As cx indicated, depends on where you start from. In addition to the changes from the tire shape (wider and taller profile), the wheel most probably will become laterally stiffer as well. The cumulative effect of all of these may make a noticable difference at the end.


----------



## Lombard

cxwrench said:


> Depends. How much do you weight and what size/pressure are you using now?


I weigh around 175lbs. Right now, I am using 622x15 wheels with 28c tires (70 PSI front/100 PSI rear). I did happen to notice visual evidence of tire rub against the chainstays (I have never felt it) indicating some flex in either my existing wheels or bike frame.

I figure if I move to wider 622x18 or 622x19 wheels, I would have to move down to 25c tires. There is also the issue that wider rims may flex enough to rub the stays. I would certainly rather have rubber hit carbon, than aluminum hit carbon.


----------



## dcgriz

Lombard said:


> . I did happen to notice visual evidence of tire rub against the chainstays (I have never felt it) indicating some flex in either my existing wheels or bike frame.
> :


- are your wheels true? Any wobbling when you spin the wheel?
- at rest, what is the spacing between the tire and the chainstays (where the tire rubs)?
- is the tire centered between the chainstays? 




Lombard said:


> .
> I figure if I move to wider 622x18 or 622x19 wheels, I would have to move down to 25c tires. There is also the issue that wider rims may flex enough to rub the stays. I would certainly rather have rubber hit carbon, than aluminum hit carbon.


Depends on the clearances you have now. Upping the rim width from a 15mm to a 17mm adds about 1-1.5mm to the tire width.
Wider rims will have less lateral flex than narrower rims but they also need the appropriate spoke bracing angles (hub geometry) and the appropriate number and type of spokes to complement that.
Chainstays taper towards the bottom bracket so no matter if the tire profile matches that of the rim, the tire rubber will always be closer to the chainstays than the rim itself. So don't worry about the aluminum rim rubbing your chainstays; it isn't happening.


----------



## Lombard

dcgriz said:


> - are your wheels true?


Yep.



dcgriz said:


> Any wobbling when you spin the wheel?


Nope.




dcgriz said:


> - at rest, what is the spacing between the tire and the chainstays (where the tire rubs)?


2007 Trek Pilot 5.0 -

Clearance between chainstay and tire: 2mm
Clearance between chainstay and rim: 8mm

2014 Synapse Carbon 5-

Clearance between chainstay and tire: 3mm
Clearance between chainstay and rim: 6mm




dcgriz said:


> - is the tire centered between the chainstays?


Yep.



dcgriz said:


> Wider rims will have less lateral flex than narrower rims but they also need the appropriate spoke bracing angles (hub geometry) and the appropriate number and type of spokes to complement that.


I would be interested in going to a higher spoke count anyway. My Shimano factory road wheels are 16/20 spoke. I did once break a spoke on a 24 spoke rear wheel and managed to loosen other spokes enough to ride 30 miles back to the start site with minimal wobble. I don't know that this would be possible with a 16 or 20 spoke wheel. I would feel better with 28 or 32.



dcgriz said:


> Chainstays taper towards the bottom bracket so no matter if the tire profile matches that of the rim, the tire rubber will always be closer to the chainstays than the rim itself. So don't worry about the aluminum rim rubbing your chainstays; it isn't happening.


Note above in my measurements that my Synapse has considerably less taper.


----------



## dcgriz

A clearance of 2 or 3 mm is very tight; I don't believe your frame will be able to fit a wider tire than what you now have. Actually 5mm should be the minimum clearance between tire and frame or tire and fork to allow for some play if something unexpected happens to your wheel (broken spoke, etc).

IMO, you will benefit from laterally stiffer wheels. As you apply load on the bike, the bottom half of your aluminum rim wheel flexes and rubs against the stays. I would not recommend going to 18 or 19mm from the 15mm you now have because you won't have as many tire choices to put on and fit in your frame; the increased width of a 17ish mm mid-depth rim like the Archetype, the HED C2, the Kinlin 279 or the Pacenti SL23 would help the wheel become laterally stiffer. You will need to balance that with a hub of suitable geometry (flange offsets and flange diameter) to develop wider spoke bracing anglees. Spoke thickness and spoke number should also be a consideration in order to complete the package. 
For your 175 lbs 28 double butted 15/16ga. spokes (Laser) should be plenty unless you pedal stroke is not smooth or you tilt the bike too much when sprinting. If the latter is the case then the thicker 14/15 ga (Race) could be used at least on the drive side of the wheel. I think 32 spokes may be a bit too much unless you want durability to trump everything else. Front I would do 20 or 24 depending on your desires although the added weight of 4 spokes is rather insignificant.

The 23mm outer width of the 17mm rim will also match the width of the tire (a 23mm that will measure about 24-25mm on that rim) and give you a nice profile, aero wise. A 25mm will grow to around 27mm, depending on the tire of course.

The factory wheels with 16/20 spokes you were referring to are typically set at higher spoke tensions because of the fewer spokes sharing the total load. As you said, loosing a spoke most probably will render the wheel useless because of the pronounced wobbling and if somehow you manage to retension the adjacent spokes you have a good chance of popping them through the rim. So most often the best course of action is a phone call to your loved ones to pick you up.

Edit to add: No matter how well the tire width matches the rim width (and people pay a lot of money to have that smooth transition), your rim will never rub the stays before the tire does simply because the tire is further deeper into the stays so don't be concerned with that.


----------



## ergott

dcgriz said:


> Edit to add: No matter how well the tire width matches the rim width (and people pay a lot of money to have that smooth transition), your rim will never rub the stays before the tire does simply because the tire is further deeper into the stays so don't be concerned with that.


Depends. My Serotta has dimples in the chainstays so the clearance is tightest right at the brake track. I tried SL23s with the bike and got the brake track into the left stay when cranking out of the saddle:cryin:

I'm using DT440s for that bike and all is well.


----------



## kbwh

My now discontinued DT Swiss RR1450 Tricon wheels are marked "Maximum tire width 25mm". They are 622x14.5.


----------



## dcgriz

ergott said:


> Depends. My Serotta has dimples in the chainstays so the clearance is tightest right at the brake track. I tried SL23s with the bike and got the brake track into the left stay when cranking out of the saddle:cryin:
> 
> I'm using DT440s for that bike and all is well.


Both my Seven Ti and Spectrum steel have dimples at the stays. Hour-glass shape stays. The tire will rub on the stays before the rim does. 
Same on both of my carbon bikes. The dimple is shaped into the inner side of the stay.

Your point is well taken though if the bikes were originally designed to only fit 23mm tires on standard rims and now wider tires/rims are used eating up most of the clearance to the stays.
I recall when I specced the Seven, they asked me what was the maximum tire size I ever planned on using on the bike; I told them 28mm. I wish I had told them 32.


----------



## Lombard

Thank you all for the replies. This is all very helpful info.

There is a lot to think about here which seems like a real balancing act. I think I can rule out 18 and 19mm rims. In the arena of 17mm rims, there doesn't seem to be much I can find other than Kinlin XC-279s. H Plus Son Archtypes and HED Belgiums only list external widths on their website. Velocity A23s are 18mm. Mavic A719 are 19mm and are more of a touring rim. Pacenti SL23s are a whopping 20.3mm!

I think it may be best for me to defer to a good custom wheel builder at my LBS who happens to also be a racer.

The one thing I'm sure about is I want a wheelset with more spokes, especially since I do quite a bit of hilly riding - not the easiest thing on a rear wheel. Next year, I will be doing some long rides in sparsely populated areas with minimal cell service. I may be over 20 miles from the nearest town.


----------



## dcgriz

A quick reference to the rim inner widths. The HED C2 and the Archetype are very similar in everything but cost. These are the two I use by far the most. I believe the Pacenti shown on the pic is the first generation; the second generation is wider.


----------



## ergott

Lombard said:


> Thank you all for the replies. This is all very helpful info.
> 
> There is a lot to think about here which seems like a real balancing act. I think I can rule out 18 and 19mm rims. In the arena of 17mm rims, there doesn't seem to be much I can find other than Kinlin XC-279s.


The DT 440 is 16mm internal and one of the highest quality out there. I'd consider that if you want something a bit wide, but not 18mm. Bonus, get the rear in offset which is nice since some hubs don't have the best flange spacing. They come in 32 spoke count and I would consider them very durable.


----------



## Lombard

dcgriz said:


> A quick reference to the rim inner widths. The HED C2 and the Archetype are very similar in everything but cost. These are the two I use by far the most. I believe the Pacenti shown on the pic is the first generation; the second generation is wider.


Thanks for the info Dcgriz. Interesting that H Plus Son Archtypes and HED Belgiums didn't list internal width on their website and the Pacentis internal width increased so much from one gen to the next. The Velocity must have also become wider. That seems to be the trend, but how much is too much. If this continues, newer road bikes will need to have wider stays.


----------



## Lombard

ergott said:


> The DT 440 is 16mm internal and one of the highest quality out there. I'd consider that if you want something a bit wide, but not 18mm. Bonus, get the rear in offset which is nice since some hubs don't have the best flange spacing. They come in 32 spoke count and I would consider them very durable.


Hmmm. These are the same external width as my standard road Shimanos, but 1mm wider internally. I'll have to look into this. Thanks!


----------



## dcgriz

Lombard said:


> Thanks for the info Dcgriz. Interesting that H Plus Son Archtypes and HED Belgiums didn't list internal width on their website and the Pacentis internal width increased so much from one gen to the next. The Velocity must have also become wider. That seems to be the trend, but how much is too much. If this continues, newer road bikes will need to have wider stays.


The Velocity on the pic was the non-tubeless version. The current version is the tubeless at 0.5mm increase. They try to make the sidewalls of a 23 mm tire flush or close to being flush with the rim walls. Outside width remained the same so clearance to the stays is the same.


----------



## cxwrench

Lombard said:


> I weigh around 175lbs. Right now, I am using 622x15 wheels with 28c tires (70 PSI front/100 PSI rear). I did happen to notice visual evidence of tire rub against the chainstays (I have never felt it) indicating some flex in either my existing wheels or bike frame.
> 
> I figure if I move to wider 622x18 or 622x19 wheels, I would have to move down to 25c tires. There is also the issue that wider rims may flex enough to rub the stays. I would certainly rather have rubber hit carbon, than aluminum hit carbon.


100psi at 175lbs?!? Jesus, that's what I weigh. On those rims I'd probably be around 75-80 rear. I'd use less than 100 w/ 23mm tires. Those 28's must feel like hell at 100.


----------



## Lombard

cxwrench said:


> 100psi at 175lbs?!? Jesus, that's what I weigh. On those rims I'd probably be around 75-80 rear. I'd use less than 100 w/ 23mm tires. Those 28's must feel like hell at 100.




Less than 100PSI on 23mm tires, really?? The 28s at 100PSI feel a lot better than the 23s ever did at 100PSI.

So if you use 75-80 on the rear, what do you use on the front?

Is this tire pressure guide below accurate? Note that the weight they have you enter is total weight of rider, bike and anything else including water bottles. I also generally carry other light repair gear since I often do long rides out to sparsely populated areas. I entered a round number of 200lbs and came up with 59 PSI front, 90 PSI rear.

Bicycle tire pressure calculator


----------



## kbwh

Lombard said:


> Less than 100PSI on 23mm tires, really??


I use 90 front 95 rear on 23mm clinchers for my 160 lbs.


----------



## cxwrench

Lombard said:


> Less than 100PSI on 23mm tires, really?? The 28s at 100PSI feel a lot better than the 23s ever did at 100PSI.
> 
> So if you use 75-80 on the rear, what do you use on the front?
> 
> Is this tire pressure guide below accurate? Note that the weight they have you enter is total weight of rider, bike and anything else including water bottles. I also generally carry other light repair gear since I often do long rides out to sparsely populated areas. I entered a round number of 200lbs and came up with 59 PSI front, 90 PSI rear.
> 
> Bicycle tire pressure calculator


I didn't bother to look at the calculator, so I don't know. Yes, less than 100psi. If you can't miss stuff big enough to pinch flat a 23mm tire at your weight and 90ish psi you need to open your eyes a little more. As you increase tire size (air volume) the pressure required goes down. So according to the physics I learned in school there is NO way a 28mm tire at 100psi will ride as well as a 23mm tire at 100psi. It will have a MUCH harsher ride. It can't work any other way...what pressure do you inflate your mtb tires to? See what I'm talking about?

I ride my Bontrager Race wheels (wider rim than yours) w/ 28mm clinchers (tubes) at 70ish rear/60ish front. They don't feel 'soft', they ride well and have great grip in corners. And they definitely are not 'slow'.


----------



## Lombard

cxwrench said:


> If you can't miss stuff big enough to pinch flat a 23mm tire at your weight and 90ish psi you need to open your eyes a little more.


LOL! I haven't had a pinch flat in a long, long time. Every flat I've had in the past few years, I've been able to recover the object that punctured me - usually a small strand of wire. The last time I had a pinch flat was my own stupidity - thinking I could hop my hybrid with 700x38c tires over a curb.



cxwrench said:


> As you increase tire size (air volume) the pressure required goes down. So according to the physics I learned in school there is NO way a 28mm tire at 100psi will ride as well as a 23mm tire at 100psi. It will have a MUCH harsher ride.


What can I say? School and physics aside, my hands and arse don't agree with you.




cxwrench said:


> It can't work any other way...what pressure do you inflate your mtb tires to? See what I'm talking about?


It depends. Dirt carriage trails: 40 PSI front, 60 PSI rear. In the woods in rock gardens and tree roots: 30 PSI front, 40 PSI rear. Apples and oranges comparison though. My mountain bike has a front and rear suspension so that provides cushioning. Also, the object of a mountain bike is not for speed, but for ruggedness. And the tires themselves have an aggressive tread compared to smooth road tires, so here again, not a good comparison.




cxwrench said:


> I ride my Bontrager Race wheels (wider rim than yours) w/ 28mm clinchers (tubes) at 70ish rear/60ish front. They don't feel 'soft', they ride well and have great grip in corners. And they definitely are not 'slow'.


Your front and rear pressures are quite close to each other. Since you ride wider rims, you are effectively increasing your tire width to around 30mm? Do you think I could get away with riding 60 PSI front with my 28s on 622x15 rims? This would be like.......um......riding on air.


----------



## Jay Strongbow

cxwrench said:


> I didn't bother to look at the calculator, so I don't know. Yes, less than 100psi. If you can't miss stuff big enough to pinch flat a 23mm tire at your weight and 90ish psi you need to open your eyes a little more. As you increase tire size (air volume) the pressure required goes down. *So according to the physics I learned in school there is NO way a 28mm tire at 100psi will ride as well as a 23mm tire at 100psi. It will have a MUCH harsher ride. It can't work any other way...what pressure do you inflate your mtb tires to? See what I'm talking about?*


No, I don't see what you're talking about at all. I don't see how a bigger tires can be much more harsh than a smaller one with the same pressure. We didn't study bike tires in my physics classes but I doubt I would have learned that same pressure results in harsher ride as the tire size goes up.

Just because people choose to and can use less pressure in bigger tires doesn't mean they are much more harsh at the same PSI they use in smaller ones.


----------



## cxwrench

Lombard said:


> LOL! I haven't had a pinch flat in a long, long time. Every flat I've had in the past few years, I've been able to recover the object that punctured me - usually a small strand of wire. The last time I had a pinch flat was my own stupidity - thinking I could hop my hybrid with 700x38c tires over a curb.
> 
> 
> 
> What can I say? School and physics aside, my hands and arse don't agree with you.
> 
> 
> 
> 
> It depends. Dirt carriage trails: 40 PSI front, 60 PSI rear. In the woods in rock gardens and tree roots: 30 PSI front, 40 PSI rear. Apples and oranges comparison though. My mountain bike has a front and rear suspension so that provides cushioning. Also, the object of a mountain bike is not for speed, but for ruggedness. And the tires themselves have an aggressive tread compared to smooth road tires, so here again, not a good comparison.
> 
> 
> 
> 
> Your front and rear pressures are quite close to each other. Since you ride wider rims, you are effectively increasing your tire width to around 30mm? Do you think I could get away with riding 60 PSI front with my 28s on 622x15 rims? This would be like.......um......riding on air.


I'm actually not sure what the tire measures on those rims, I've never checked. I wouldn't want to go that low on narrow rims because the shape of the tire isn't as stable. That's one of the 2 major benefits of wide rims...a more stable foundation for the tire and less of a 'light bulb' shape. 

Your hands and bum are wrong, I don't know what else to say. This is easily proved by looking at some rims that have max pressure ratings listed by tire size...the wider tire used, the lower the max pressure allowed. At the extreme a 4.00" fatbike rim is rated for a max pressure of 25psi. You ride those tires at 15psi and they feel hard as a 30mm tire at 70-80. 



Jay Strongbow said:


> No, I don't see what you're talking about at all. I don't see how a bigger tires can be much more harsh than a smaller one with the same pressure. We didn't study bike tires in my physics classes but I doubt I would have learned that same pressure results in harsher ride as the tire size goes up.
> 
> Just because people choose to and can use less pressure in bigger tires* doesn't mean they are much more harsh at the same PSI they use in smaller ones.*


Uhhmmm...yes it does. Might be Boyle's law? Can't remember, can anyone help out here?


----------



## ergott

When was the last time you inflated a car tire to 100psi?


----------



## Jay Strongbow

cxwrench said:


> Uhhmmm...yes it does. Might be Boyle's law? Can't remember, can anyone help out here?


interesting. Doesn't seem logical to me but I'll take your word for it because I don't know any scientific law either way. I'd assume that 100psi, or whatever, would feel equally as hard regardless of tire size but it wouldn't be the first time an assumption of mine was wrong.


----------



## cxwrench

Jay Strongbow said:


> interesting. Doesn't seem logical to me but I'll take your word for it because I don't know any scientific law either way. I'd assume that 100psi, or whatever, would feel equally as hard regardless of tire size but it wouldn't be the first time an assumption of mine was wrong.


Try inflating a 2.5" mtb tire to 100psi and tell me what happens. I'd not recommend trying it on anything bigger than that, you'd probably get hurt. 


Don't forget your hearing protection.


----------



## Lombard

cxwrench said:


> I wouldn't want to go that low on narrow rims because the shape of the tire isn't as stable. That's one of the 2 major benefits of wide rims...a more stable foundation for the tire and less of a 'light bulb' shape.


Understood.




cxwrench said:


> Your hands and bum are wrong.....
> 
> Uhhmmm...yes it does. Might be Boyle's law? Can't remember, can anyone help out here?


This sort of reminds me of the "bees can't fly" argument. Though nobody told the bee he/she couldn't fly.

Boyle aside, my hands and bum don't lie.


----------



## Jay Strongbow

cxwrench said:


> Try inflating a 2.5" mtb tire to 100psi and tell me what happens. I'd not recommend trying it on anything bigger than that, you'd probably get hurt.
> 
> 
> Don't forget your hearing protection.


Pounds PER square inch. I still don't understand how the pressure could be any different on a given square inch, thus everywhere, with two different size tires both at 100 PSI but whatever. I'll take your word for it.


----------



## cxwrench

Lombard said:


> Understood.
> 
> 
> 
> 
> This sort of reminds me of the "bees can't fly" argument. Though nobody told the bee he/she couldn't fly.
> 
> Boyle aside, my hands and bum don't lie.


All you have to do is put your weight into one of those pressure calculators and then change the tire size. Guess what else will change?


----------



## Lombard

cxwrench said:


> All you have to do is put your weight into one of those pressure calculators and then change the tire size. Guess what else will change?




I believe that is *recommended* pressure. As in wider tires* CAN* be ridden at lower pressures.

Another thing to note is that I have used Maxxis Re-Fuse tires for awhile - in both 25c and 28c. Both have a max pressure rating of 120 PSI. Their 23c also has a max pressure rating of 120 PSI.


----------



## cxwrench

Lombard said:


> I believe that is *recommended* pressure. As in wider tires* CAN* be ridden at lower pressures.
> 
> Another thing to note is that I have used Maxxis Re-Fuse tires for awhile - in both 25c and 28c. Both have a max pressure rating of 120 PSI. Their 23c also has a max pressure rating of 120 PSI.


Correct, but why would you inflate to higher pressure than that? You'd have less comfort, less traction, and more rolling resistance. Doesn't make any sense, does it?


----------



## Marc

cxwrench said:


> Uhhmmm...yes it does. Might be Boyle's law? Can't remember, can anyone help out here?


Well it gets very tricky. Boyle's assumes gases are Ideal, which starts being a rash assumption as pressures go up. Also tires have give to them and stretch/deform under any kind of load-like that of the resting weight of the bicycle itself or bike+rider.

History Side Lesson: The reason the Safety Bicycle took off in fact because a fellow by the name of Dunlop (yes _that _Dunlop) implmented the first pneumatic bicycle tire. Now, fun sidefact: Dunlop thought he had invented the idea only to be informed by the Patent Office that the idea had been patented in France _4 decades before_. See the Bicycle hither to had only had solid rubber "tires", which were about as comfortable on your bum as you would expect, remember too that we're talking 1840-1880 which at best all you had were cobble roads with cobbles made by prison chaingangs. Pneumatic tires were added to provide suspension and shock absorption where there hadn't been any. And so with a basic suspension, the Safety Bicycle took off in popularity. This is all very interesting and seems non-salient...until you remember that by overpressurizing your tires you're lessening the dampening ability of your suspension-that is your pneumatic tires.


The side effect of overpressurization is observable with difficulty in reduction of contact patch size. Because

Pressure= Force/Area

Therefore

Area (Contact Patch)= Force/Area

Thuse as you crank the pressure, you shrink the contact patch....not only reducing the dampening ability of your tires by making them harder, but also decreasing the area to which rough road surface energy is spread out through the tire.


FLO Cyling - The Contact Patch... Why Wider is Better


----------



## Lombard

cxwrench said:


> Correct, but why would you inflate to higher pressure than that? You'd have less comfort, less traction, and more rolling resistance. Doesn't make any sense, does it?



Point taken, CX. I think while we really know better, many of us are still ingrained in the old school "more air is faster" arena.

I have yet to try 59 PSI on my road bike front tire as the table states. That just seems low. Not to mention that 1) You probably lose about 5 PSI right off the bat when you disconnect your pump and 2) Most pump gauges have an error of up to 10 PSI. I think it is human nature to fear too little air than too much air.


----------



## Lombard

Marc said:


> Well it gets very tricky. Boyle's assumes gases are Ideal, which starts being a rash assumption as pressures go up. Also tires have give to them and stretch/deform under any kind of load-like that of the resting weight of the bicycle itself or bike+rider.
> 
> History Side Lesson: The reason the Safety Bicycle took off in fact because a fellow by the name of Dunlop (yes _that _Dunlop) implmented the first pneumatic bicycle tire. Now, fun sidefact: Dunlop thought he had invented the idea only to be informed by the Patent Office that the idea had been patented in France _4 decades before_. See the Bicycle hither to had only had solid rubber "tires", which were about as comfortable on your bum as you would expect, remember too that we're talking 1840-1880 which at best all you had were cobble roads with cobbles made by prison chaingangs. Pneumatic tires were added to provide suspension and shock absorption where there hadn't been any. And so with a basic suspension, the Safety Bicycle took off in popularity. This is all very interesting and seems non-salient...until you remember that by overpressurizing your tires you're lessening the dampening ability of your suspension-that is your pneumatic tires.
> 
> 
> The side effect of overpressurization is observable with difficulty in reduction of contact patch size. Because
> 
> Pressure= Force/Area
> 
> Therefore
> 
> Area (Contact Patch)= Force/Area
> 
> Thuse as you crank the pressure, you shrink the contact patch....not only reducing the dampening ability of your tires by making them harder, but also decreasing the area to which rough road surface energy is spread out through the tire.
> 
> 
> FLO Cyling - The Contact Patch... Why Wider is Better



Yes, we know all the advantages to wider and it all makes sense. So how in light of all the scientific evidence did the widespread belief that super skinny tires with bomber pressure were the fastest thrive just a few years ago?


----------



## Jwiffle

Lombard said:


> Point taken, CX. I think while we really know better, many of us are still ingrained in the old school "more air is faster" arena.
> 
> I have yet to try 59 PSI on my road bike front tire as the table states. That just seems low. Not to mention that 1) You probably lose about 5 PSI right off the bat when you disconnect your pump and 2) Most pump gauges have an error of up to 10 PSI. I think it is human nature to fear too little air than too much air.


You don't lose air when removing the pump. The air you hear escaping is from the pump hose, not the tire/tube. It reads lower the next time you put on the pump, because at that point air is let into the hose from tire/tube.

As for the second, just always use the same pump so you have consistent readings, even if not perfectly accurate.


----------



## cxwrench

Jwiffle said:


> You don't lose air when removing the pump. The air you hear escaping is from the pump hose, not the tire/tube. It reads lower the next time you put on the pump, because at that point air is let into the hose from tire/tube.
> 
> As for the second, just always use the same pump so you have consistent readings, even if not perfectly accurate.


^This^


----------



## deviousalex

Jwiffle said:


> You don't lose air when removing the pump. The air you hear escaping is from the pump hose, not the tire/tube. It reads lower the next time you put on the pump, because at that point air is let into the hose from tire/tube.


I've lost air when sealant was gunking up the valve in a tubeless tire. But yes, in a typical clincher at high PSI I agree.


----------

