# Newbie Tire Pressure Question



## adiggs23 (Apr 28, 2011)

Hello everyone. I have been riding my sons Specialized Allez for about three weeks and am really enjoying it. I have been riding three or four times a week, and did a 35 mile ride last Saturday. Today I went for a lunch time ride at work and my rear tire was low on air. I normally use my floor pump at home to gauge tire pressure as I dont have a gauge that works with the presta valve. I used his bike mounted pump to fill the tire and that brings me finally to my rookie question. When you repair or replace a tube on a ride, which I understand will happen sooner or later, do most riders carry a tire gauge to check inflation pressure? All the online videos about repairing flats I have watched just say re-inflate. Guy at LBS told me it was hard to find a good gauge to use with the presta valve, and that they were expensive so just use the gauge on my floor pump. Never thought to ask what do I do on the side of the road.


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## JCavilia (Sep 12, 2005)

> do most riders carry a tire gauge to check inflation pressure?


No, most don't. You just use your thumb (which you educate periodically by squeezing a properly-inflated tire). You get close enough that way.


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## andulong (Nov 23, 2006)

Some of the small pumps have a built-in gauge but I just do as JCavilia says.


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## Hooben (Aug 22, 2004)

Just pump it up until the tire feels firm and hard. A frame pump would probably not be able to over inflate the tire.


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## AndrwSwitch (May 28, 2009)

Compare it to your other tire.


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## PJ352 (Dec 5, 2007)

AndrwSwitch said:


> Compare it to your other tire.


Might not be the best method if the 'other tire' had 25 PSI. 

Just sayin'..


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## Rusted Angel (Sep 19, 2010)

If my tire's max air pressure is 125 psi, how much actual pressure I'm supposed to put in?

Full 125, 120, 115, 110?

What's the lowest I can have it?


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## Drew Eckhardt (Nov 11, 2009)

Rusted Angel said:


> If my tire's max air pressure is 125 psi, how much actual pressure I'm supposed to put in?
> 
> Full 125, 120, 115, 110?
> 
> What's the lowest I can have it?


Depends on tire size and how big you are.

I'd ride tires big enough that 90-95 PSI front and 100-105 rear didn't produce pinch flats since that makes for a comfortable and fast ride.

You can get there with 23mm tires at 150-160 pounds or 25mm at 180-200


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## Rusted Angel (Sep 19, 2010)

Drew Eckhardt said:


> Depends on tire size and how big you are.
> 
> I'd ride tires big enough that 90-95 PSI front and 100-105 rear didn't produce pinch flats since that makes for a comfortable and fast ride.
> 
> You can get there with 23mm tires at 150-160 pounds or 25mm at 180-200


I'm about 175 pounds and I ride a Specialized Allez with Specialized Mondo Sport, 700x23c, wire bead, 60TPI, w/ Flak Jacket protection. The tire says the max psi is 125# and I set it at 115# and I check it every other ride and if it falls below 100# I put more air in it but I really don't know nothing about it and I'm just guessing.


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## wim (Feb 28, 2005)

Another vote for the educated thumb—you really don't need exact pressures in a bicycle tire. I'm lazy and old, so I thumb-check my tires before a ride and put some more air into them when they feel a little soft (which is about once every two weeks).

Also consider that with almost all on-the-road inflation gadgets, you'll probably not be able to meet (let alone exceed) maximum recommended tire pressure anyway.


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## ZoSoSwiM (Mar 7, 2008)

When pumping at home the floor pump should have a gauge. While pumping up a tire out on the road your thumb will work well enough. 

On that note I usually ride my 23mm tires around 105. Last Friday I jumped on my bike with out airing up. Totally forgot. Rode 52 miles with both tires around 85psi and everything went fine. No issues and I was actually rather comfortable. Wouldn't of wanted to sprint or anything because of side to side wobble though!


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## PJ352 (Dec 5, 2007)

Rusted Angel said:


> *I'm about 175 pounds *and I ride a Specialized Allez with Specialized Mondo Sport, 700x23c, wire bead, 60TPI, w/ Flak Jacket protection. *The tire says the max psi is 125# and I set it at 115# *and I check it every other ride and if it falls below 100# I put more air in it but I really don't know nothing about it and I'm just guessing.


Generally, tire manufacturers recommend max PSI for riders 180+. You're slightly under that, so I think you'll do fine maintaining the 115 PSI at the rear. And since you keep a close check on it, you could probably go to ~105 at the front.

One caveat: Road conditions/ riding style should also be considered.


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## Hawkeye16 (Apr 29, 2011)

Really Max PSI for riders 180+?

So my tires say max 130psi I should get close to that? I generally pump to 115-120psi front and rear. I weigh 210 btw.


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## Rusted Angel (Sep 19, 2010)

PJ352 said:


> Generally, tire manufacturers recommend max PSI for riders 180+. You're slightly under that, so I think you'll do fine maintaining the 115 PSI at the rear. And since you keep a close check on it, you could probably go to ~105 at the front.
> 
> One caveat: Road conditions/ riding style should also be considered.


Thanks for the advice!


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## cxwrench (Nov 9, 2004)

Hawkeye16 said:


> Really Max PSI for riders 180+?
> 
> So my tires say max 130psi I should get close to that? I generally pump to 115-120psi front and rear. I weigh 210 btw.


why don't you tell us what tires you have?


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## Drew Eckhardt (Nov 11, 2009)

PJ352 said:


> Generally, tire manufacturers recommend max PSI for riders 180+.
> You're slightly under that, so I think you'll do fine maintaining the 115 PSI at the rear. And since you keep a close check on it, you could probably go to ~105 at the front.


The maximum is some safe margin below where the tire blows off the rim.

A more reasonable starting number is whatever produces a 15% drop

http://www.bccclub.org/documents/Tireinflation.pdf

which

1) Is more than you need to avoid pinch flats in reasonable road riding situations (I've bent rims from pot holes without a snake bite in a 25mm front tire inflated to 90-95psi with 200 pounds of rider and luggage).

2) IIRC isn't out of line with the instruction sheet that comes tied to folding Continental tires.

An exception would be when you're racing and perhaps competitive enough to be off-the-front at some point where you might care about a few percent less power lost to rolling resistance. A Radio Shack mechanic reported 116psi with less for lighter riders and rain. OTOH Roger De Vlaeminck won Paris-Roubaix four times with 65 psi in his tubulars.


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## AndrwSwitch (May 28, 2009)

Hawkeye16 said:


> Really Max PSI for riders 180+?
> 
> So my tires say max 130psi I should get close to that? I generally pump to 115-120psi front and rear. I weigh 210 btw.


I'd say that if you're happy with your tires at 115-120, that's your answer. If you haven't experimented, I highly encourage it.


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## Camilo (Jun 23, 2007)

As for pumping the tire on the road, here's what I do.

I just pump the tire as hard as I possibly can with my frame pump. That's your rule of thumb on the road - you can't possibly over inflate it with a frame or mini pump.

I doubt I can get it harder than 100-110 PSI if even that. I haven't measured in while, but in my youth that's what I could get by bearing down on a full sized frame pump. I can get ridable but not much more with a mni-pump.


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## PJ352 (Dec 5, 2007)

AndrwSwitch said:


> I'd say that if you're happy with your tires at 115-120, that's your answer. If you haven't experimented, I highly encourage it.


Exactly. To clarify my previous post re: 'recommended' pressures, they're just that - _recommended_ (by Michelin in this case), but feel free to experiment. 

Here's a link to the chart:
http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view


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