# Tire pressures for heavy riders?



## ch35iM (Oct 28, 2016)

I keep searching the threads but I can't find much I can relate to. I'm 220lb with 25mm conti GP 4 seasons. The tire pressure calculator for 60/40 distribution has my rear at around 130 and the front around 85. I'm concerned about the rear as the max inflation is 120psi which is what I've been running it at. My bike shop said I don't need that much and should be around 100 rear. I feel like I try a different pressure every day but can't seem to find one that rolls right without going up to 135. 100 just seems too low

any inputs??


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## bubble (May 19, 2007)

ch35iM said:


> I keep searching the threads but I can't find much I can relate to. I'm 220lb with 25mm conti GP 4 seasons. The tire pressure calculator for 60/40 distribution has my rear at around 130 and the front around 85. I'm concerned about the rear as the max inflation is 120psi which is what I've been running it at. My bike shop said I don't need that much and should be around 100 rear. I feel like I try a different pressure every day but can't seem to find one that rolls right without going up to 135. 100 just seems too low
> 
> any inputs??


~105psi for the rear, a couple less for the front. You increase the risk of flatting on steep descents by running 115+. Moving to a higher volume tire solves a lot of problems.

'Rolls right' can be misleading; if it doesn't corner/brake right you wanna up the pressure, but the losses from friction are fairly linear and fairly subtle below 'ideal' pressure, so they shouldn't be obvious.

I'm ~215lbs myself.


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## Mike T. (Feb 3, 2004)

IMO, if you *need* more than 100 then you need tires with more volume. And by the word "need" I mean needing more pressure to prevent pinch-flatting. I'm 175 lbs and I use about 80f/90r and they're probably 70/80 before I re-inflate. I don't pinch flat and I'm a "performance" rider and those pressures don't slow me down. Higher pressures can make you slower by bouncing you up in the air and by rider fatigue from a harsh ride.


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## Peter P. (Dec 30, 2006)

Mike T. said:


> IMO, if you *need* more than 100 then you need tires with more volume.


Exactly. If you need more pressure, you need a larger tire. And if your bike will only fit 25mm tires when you need larger tires, then you NEED a different bike.

I'll admit, 220lbs. with 25mm tires-start thinking about upsizing.


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## Mike T. (Feb 3, 2004)

Peter P. said:


> And if your bike will only fit 25mm tires when you need larger tires, then you NEED a different bike.


That would be tough medicine to swallow if you were 200lb+ and had been sold a road bike that was really designed for sub-160lb road racers (low spoke numbers, narrow tires, low tire clearances).


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## dcgriz (Feb 13, 2011)

ch35iM said:


> I keep searching the threads but I can't find much I can relate to. I'm 220lb with 25mm conti GP 4 seasons. The tire pressure calculator for 60/40 distribution has my rear at around 130 and the front around 85. I'm concerned about the rear as the max inflation is 120psi which is what I've been running it at. My bike shop said I don't need that much and should be around 100 rear. I feel like I try a different pressure every day but can't seem to find one that rolls right without going up to 135. 100 just seems too low
> 
> any inputs??


The calculator you are refering to is based on Frank Berto's tire pressure charts that focused on 15% tire drop. Berto made the chart in the 1990s, when tires were much narrower and predominantly with stiffer sidewalls than current trends dictate. The 15% as desirable tire drop was based on the recommendations of several tire manufacturers, but not on actual testing. So the chart shows how much you need to inflate an average 1990s tire to achieve a tire drop of 15% – nothing less and nothing more.

Berto’s chart still is a good starting point. Inflate your tires to the pressures it recommends, then experiment by adding or letting out some air.

The minimum safe pressure is higher for more supple casings. Stiff casings hold up the bike more, and thus require less air pressure.

Don’t run your tires so low that the casing cords start to break. That happens only at very low pressures, but if you start seeing multiple lines across the casing where cords have broken, inflate the tires a bit more.

See what feels best to you. That is the optimum tire pressure for you. Don’t worry about tire pressure any further! 

Here is a summary in two sentences:

1. Ride the tire pressure that feels good to you.
2. When in doubt, let out some air.

IMO, you probably will end up balancing performance (aka "feel") and comfort at around 85 psi for the front and 100 psi for the rear at your 220 lbs body weight and 25mm Contis GP 4S. Noone but you will be the better judge on that. Of note is that the next size up of GP 4S labeled as 28mm only measures 26.5 mm on 17mm rims so when time comes to replace tires these may be another option at even lower inflation presure.


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## Lombard (May 8, 2014)

dcgriz said:


> Here is a summary in two sentences:
> 
> 1. Ride the tire pressure that feels good to you.
> 2. When in doubt, let out some air.



Good advice, DC. But you missed the rhyme on 2) When in *doubt*, let some air *out*.  

ch35iM, is this the link you used:

Bicycle tire pressure calculator 

Try entering 28mm tires and see what you get. If you can fit them between your stays, by all means this is a good way to go. I am 170lbs. and went to 28mm. I will never go back. The ride is just so much nicer!


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## cobra_kai (Jul 22, 2014)

If you have a pair of calipers you may want to measure how wide your tires actually are. My 25mm GP4000 measure about 27.5 mm on 20 mm wide internal rims, and 25 mm Michelin Pro4 Endurance measure 28 mm on 18 mm wide internal rims.


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## ch35iM (Oct 28, 2016)

Lombard said:


> Good advice, DC. But you missed the rhyme on 2) When in *doubt*, let some air *out*.
> 
> ch35iM, is this the link you used:
> 
> ...


thats the link. And I was also thinking of going 28s. I can definitely squeeze them. My current rear tire is shot after 900 miles at max pressure.... tread started breaking off... maybe I am too high


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## Migen21 (Oct 28, 2014)

I'm a little heavier than you at 225 or so.

I can't comprehend riding at pressures that high. 

I run 25 4 seasons as well (sometimes 28s). If my rear tire is over 100 psi I'm pretty miserable.

My goto pressure is 75f/85r. I go by feel to determine when they need a little air. 

I put a premium on comfort. I go as low as I can and still be comfortable that I won't pinch flat.

Sent from my Pixel using Tapatalk


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## Lombard (May 8, 2014)

ch35iM said:


> thats the link. And I was also thinking of going 28s. I can definitely squeeze them. My current rear tire is shot after 900 miles at max pressure.... tread started breaking off... maybe I am too high




Really shot after only 900 miles? Max pressure won't do this and neither will 220lbs. Only poor quality will. If that ever happened to me, I would never use that brand of tire again.


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## ch35iM (Oct 28, 2016)

Lombard said:


> Really shot after only 900 miles? Max pressure won't do this and neither will 220lbs. Only poor quality will. If that ever happened to me, I would never use that brand of tire again.


I would tend to agree but I think I am the only one that had a bad experience with this tire





Migen21 said:


> I'm a little heavier than you at 225 or so.
> 
> I can't comprehend riding at pressures that high.
> 
> ...


Maybe ill try something like that later today and see how it feels, I never thought of going that low..


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## Soonerinfrisco (May 30, 2006)

Wow my head is now spinning! Been playing with my new HED Plus Belgium wheels and pressures. Running Spec Roubaix 23/25 tires. I weigh 260 lbs or so and ride a Roubaix. I rode with about 90 psi in rear last night and probably same in front. The tires felt OK but my gut was a bit worried that I was too low. thoughts? Is 90 psi too low for a guy my size?


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## Mike T. (Feb 3, 2004)

IMO 25 (and especially 23) is too low for a guy your size. I'll bet your bike won't take the tires that I think you should have.


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## Migen21 (Oct 28, 2014)

I'm close to that weight, and rode Belgium Plus with Conti 4 Seasons 25mm just fine. I rode them at about 75f 85r and no issues with pinch flats. 

This of course depends now how 'heavy' you ride, and the conditions. If you are on a relatively clean surface and are good about un-weighting the bike over 'problems', you can probably get away with 25's.

That said, you are going to be a lot more comfortable (both physically, and for flat avoidance) running 28s.


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## Jay Strongbow (May 8, 2010)

Lombard said:


> Really shot after only 900 miles? Max pressure won't do this and neither will 220lbs. Only poor quality will. If that ever happened to me, I would never use that brand of tire again.


um, no. Tires definitely wear out faster at higher pressure.


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## Lombard (May 8, 2014)

Jay Strongbow said:


> um, no. Tires definitely wear out faster at higher pressure.




Seriously? At *higher* pressure or at pressures that are* too high*? My guess is that it is not an even curve. I would also believe that tires will wear out faster at *too low* pressure or anything outside the realm of normal. 

I would say that unless the pressure is way outside that realm, 900 miles is highly unusual.


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## cxwrench (Nov 9, 2004)

ch35iM said:


> I keep searching the threads but I can't find much I can relate to. I'm 220lb with 25mm conti GP 4 seasons. The tire pressure calculator for 60/40 distribution has my rear at around 130 and the front around 85. I'm concerned about the rear as the max inflation is 120psi which is what I've been running it at. My bike shop said I don't need that much and should be around 100 rear. I feel like I try a different pressure every day but can't seem to find one that rolls right without going up to 135. 100 just *seems too low*
> 
> any inputs??


Seems=feels. You 'think' that harder should be faster because it 'feels' fast. In reality it's slower because it bounces off the bumps and texture of the pavement. It also reduces traction in corners. Physics (do some research) says lower pressures (down to the point you where you waste energy to hysteresis) are faster. 
Think of it this way: Push a shopping cart on the smooth grocery store floor, then push it outside to the parking lot. Rougher surface, same hard wheel. Takes more push to make it move, right? The bicycle equivalent would be a wood track and then the road.
That's obviously an extreme example, but the idea is the same, just not as much difference.


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## Lombard (May 8, 2014)

cxwrench said:


> Think of it this way: Push a shopping cart on the smooth grocery store floor, then push it outside to the parking lot. Rougher surface, same hard wheel. Takes more push to make it move, right? The bicycle equivalent would be a wood track and then the road.
> That's obviously an extreme example, but the idea is the same, just not as much difference.



Good analogy! This is why climbing a hill on hardpack requires more energy than on pavement. And in the real world, roads have imperfections anyway. 

If roads were glass, then higher pressures would be faster. Of course then there would also be the obvious problem of stopping or lack thereof.  

Interestingly, my knobby tired mountain bike rolls easier on dirt than on pavement. Or maybe it just seems that way?


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## bmach (Apr 13, 2011)

Put them at 100psi and try riding. If you pinch flat then you need more if you don't you can try a little less or just stay there. But at 130psi you should just use a solid tire. Just my two cents.


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## Lombard (May 8, 2014)

bmach said:


> Put them at 100psi and try riding. If you pinch flat then you need more if you don't you can try a little less or just stay there. But at 130psi you should just use a solid tire. Just my two cents.



I am always amazed by people who recommend using equal pressures for front and rear. This makes no sense. At your weight try 90PSI front / 110PSI rear and go from there.


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## Clipped_in (May 5, 2011)

bubble said:


> ~105psi for the rear, a couple less for the front.


This^^^^^^ It really doesn't need to be more complicated than that.


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## cxwrench (Nov 9, 2004)

bmach said:


> Put them at 100psi and try riding. If you pinch flat then you need more if you don't you can try a little less or just stay there. But at 130psi you should just use a solid tire. Just my two cents.


So you're basing your pressure recommendation soley on whether he pinch flats or not? Seriously? Say he does pinch flat once or twice a year...what about the other 99.99999% of the time? His tires would be overinflated, right? Why not keep your eyes open and avoid pinch flats. If you get one or 2 a year, what's the problem? You'd have proper inflation for the rest of the time. I'll never understand advice like this, it makes zero sense.

Short story: You don't inflate your tires to avoid pinch flats, you inflate them to a pressure that provides the ride quality and traction you want.


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## Mike T. (Feb 3, 2004)

cxwrench said:


> So you're basing your pressure recommendation soley on whether he pinch flats or not? Seriously? Say he does pinch flat once or twice a year...what about the other 99.99999% of the time? His tires would be overinflated, right? Why not keep your eyes open and avoid pinch flats. If you get one or 2 a year, what's the problem? You'd have proper inflation for the rest of the time. I'll never understand advice like this, it makes zero sense.
> 
> Short story: You don't inflate your tires to avoid pinch flats, you inflate them to a pressure that provides the ride quality and traction you want.


Excellent advice.


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## bmach (Apr 13, 2011)

I believe I said if you don't pinch flat then try lowering it. You have to start somewhere and adjust from there. cx and mike you both explained why higher inflated tire are not faster, I gave him an idea for a starting point.


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## cxwrench (Nov 9, 2004)

bmach said:


> I believe I said if you don't pinch flat then try lowering it. You have to start somewhere and adjust from there. cx and mike you both explained why higher inflated tire are not faster, I gave him an idea for a starting point.


But you based your advice on whether he pinch flatted or not. I can read.


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## smokva (Jul 21, 2004)

Lombard said:


> I am always amazed by people who recommend using equal pressures for front and rear. This makes no sense. At your weight try 90PSI front / 110PSI rear and go from there.


I ride 25 mm tires on 14 mm (internal) rims or 23 mm tires on 18 mm (internal) rims inflated to 8 bar (115 PSI). I pump front and rear at the same preassure. With my 105 kg I'm afraid to go below 8 bar rear because of pinch flats and on front below 8 bars I have this really awful feeling of empty tire in spirnts >1300W when I shift my weight to the front. So, it is 8 front and rear for me for tires that are measured 25/26 mm on the rim..
While I was riding 23 mm tires on 14/15 mm rims I had to go to 10 bars (145 PSI), because of pinch flats that I would get even on 9 bars.


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## cxwrench (Nov 9, 2004)

smokva said:


> I ride 25 mm tires on 14 mm (internal) rims or 23 mm tires on 18 mm (internal) rims inflated to 8 bar (115 PSI). I pump front and rear at the same preassure. With my 105 kg I'm afraid to go below 8 bar rear because of pinch flats and on front below 8 bars I have this really awful feeling of empty tire in spirnts >1300W when I shift my weight to the front. So, it is 8 front and rear for me for tires that are measured 25/26 mm on the rim..
> While I was riding 23 mm tires on 14/15 mm rims I had to go to 10 bars (145 PSI), because of pinch flats that I would get even on 9 bars.


Sounds like you need to keep your eyes on the road. I can't remember the last time I pinch flatted...if ever. I'll bet you spend a LOT more time cornering than sprinting or pinch flatting. Lower pressure would give you more traction. And...you need bigger tires mounted on wider rims. Big time. 28's on 20ishmm internal width rims. This would basically eliminate pinch flats, unless you're sprinting blindfolded on gravel.


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## Fredrico (Jun 15, 2002)

cxwrench said:


> Short story: You don't inflate your tires to avoid pinch flats, you inflate them to a pressure that provides the ride quality and traction you want.


That's right. And a heavy guy who wants to make it bouncing over steel plates, manhole covers, and the occasional misalignment in pavement, is just fine airing up to 100-110. His weight will make the ride just as comfortable as a lighter weight guy would feel riding below 90 psi.

Also upon the advice here, I tried airing up the front of the commuter 28 mm tire to 80 psi, and it felt sluggish, and like it was going flat when I hit bumps. I like the feel of the road at 90 psi; front for feel of the road; back to handle my weight, 160 lbs. 90 psi with 28Cs and 95-105 psi for 25Cs provides the quality and traction I want where I ride: on paved roads.


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## rcb78 (Jun 15, 2008)

Not that this thread hasn't been beat to death yet, but as a heavier rider I'll throw in my 0.02. I'm 'up' for the year right now at about 215lbs. Depending on the tire I'm running and the wheels they're mounted on, I run 70f/80r on the low side and as high as 80f/95r. Tires are either Mich or Conti both in 700x25. I don't think I've ever had a pinch flat, but I have felt the tires squirm in hard turns at the lower pressure, but I only run the lower side when it's wet out so I'm not really pushing it in those conditions anyways.
When I have road tires on my CX bike, I run 700x28 Contis and I usually have them at about 55f/60r. And I bet some people would cringe at how low I run my actual cross tires at my weight.


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## smokva (Jul 21, 2004)

cxwrench said:


> Sounds like you need to keep your eyes on the road. I can't remember the last time I pinch flatted...if ever. I'll bet you spend a LOT more time cornering than sprinting or pinch flatting. Lower pressure would give you more traction. And...you need bigger tires mounted on wider rims. Big time. 28's on 20ishmm internal width rims. This would basically eliminate pinch flats, unless you're sprinting blindfolded on gravel.


Where I live there are lot of roads like this, so you can look as much as you want you won't see everything


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## HFroller (Aug 10, 2014)

smokva said:


> Where I live there are lot of roads like this, so you can look as much as you want you won't see everything
> View attachment 317519


Hey, I know where you took that picture! I recognize that road surface! 

Well, I really don't, because there are too many roads like that where I ride. I could take 20 similar pictures each trip. Those lower pressures are not for me, and at 65 kg I'm not exactly a clydesdale.


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## DangerousDan (Jun 18, 2016)

I too want to put in my 0.03CDN (about 2 cents us). I am quite a bit heavier than most of the folks weighing in here (about 250 lbs). My ride is a 63 cm Peugeot CFX-10 frame set that I bought new in 1982 or so, and haven't seen any reason to replace. Yeah, it has a lot of miles so some of the components are a bit newer. It is about 20 lbs all up.

I have been running Conti Grand Prix 4000S II 700 X 25C tires on DT Swiss TK540, which are 19mm inner width. I have played with tire pressure and I have settled in at 105 PSI. I have had minimal trouble with flats, even on the rough roads in MN/ND.

What I am puzzled by are the claims that lower pressure does not increase rolling resistance, or did I misread what was said? The web site Bicycle Rolling Resistance | Rolling Resistance Tests has tested the Contis at pressures from 60 to 120 PSI. Rolling resistance is absolutely lower at 120 PSI than at 60 PSI.

Their numbers agree with my impression. I notice increased resistance with these tires below 80 PSI or so. I suspect that my weight has something to do with this.

They do say that the rolling resistance of the 28C would be lower, but they measure them at 31mm on their test rim which is a 17C. I am not sure what impact my 19C rims would have, so they might well be wider on my rims.

I am not sure they would fit my frame or brakes (Dura-Ace 7800). Before I buy my next set of tires I will measure the frame and brakes to see if a 32 mm tire will fit in there.

Rolling resistance is not the only thing to consider when setting the pressure. I am normally on the bike for commuting (short ride) or my daily workout (between 20 and 50 miles).

Traction and comfort will absolutely be impacted by changes in pressure. I am OK with both at 105 PSI. Wear might change as well, but it has not been an issue with these tires. The rear is pretty worn out at around 2500 miles.

My general heuristic for setting tire pressures are as follows:
Start near the top limit for my tire/rim. My upper limit was 120 PSI and I started at 115.
Drop pressure by 5 PSI between each test ride.
Go with what feels good.

If you get a bunch of pinch flats consider a bigger tire or a change of riding style to look ahead for obstacles. There is an expansion joint on my commute that has expanded one time too many and I am sure it would flatten my tires even at 105 PSI.


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## Migen21 (Oct 28, 2014)

DangerousDan said:


> I too want to put in my 0.03CDN (about 2 cents us). I am quite a bit heavier than most of the folks weighing in here (about 250 lbs). My ride is a 63 cm Peugeot CFX-10 frame set that I bought new in 1982 or so, and haven't seen any reason to replace. Yeah, it has a lot of miles so some of the components are a bit newer. It is about 20 lbs all up.
> 
> I have been running Conti Grand Prix 4000S II 700 X 25C tires on DT Swiss TK540, which are 19mm inner width. I have played with tire pressure and I have settled in at 105 PSI. I have had minimal trouble with flats, even on the rough roads in MN/ND.
> 
> ...


Interesting. I am similar in size to you (6'5" 225lbs, but was nearly 300lbs and worked my way down). 

My process is similar to yours, but I *start* at about 100psi, and go down from there. I rode 9k miles in 2016. About 80% of those mile were on 25mm and 28mm Conti 4 Seasons (50/50 between these two), and 20% on Conti 4000s II's. These tires were mounted on HED Belgium C2 and HED Belgium Plus rims (depending on the bike).

I settled on about 80f/85r for my pressures. This is mostly on relatively clean asphalt and concrete, but I'm not shy at all about hopping off onto a gravel path and frequently ride on wet, slick, and mossy surfaces (in the Pacific Northwest). 

Zero pinch flats, and only a couple of puncture flats with this setup. I find if I raise the pressure much above 85 the ride gets more harsh and I feel it in both fatigue and soreness. While it's not the only factor, my rides got longer as my tire pressures went down (I used to ride at or near 100psi). The bike feels more planted in the corners, especially on wet surfaces, and it just handles better. I've tried going back up to higher pressures, and really just don't like it. 

Once the weather warms up and I'm riding outdoors again, I'll be strictly on 28mm Contis on the road bike, running at ~80 psi.


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