Tire Pressure sweet spot

Discuss light weight issues concerning road bikes & parts.
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Fourthbook
Posts: 256
Joined: Fri Sep 30, 2011 2:11 pm
Location: Columbus, Ohio

by Fourthbook

I'd like your thoughts on what tire pressure to use for my daily rides on nice roads w/ Enve 3.4s & Conti Comps or Vittoria Evos. I usually have them at 140 psi with no wear or comfort issues but wonder if a lower pressure would be more adviseable.

What do you recommend for general riding for tubulars in good conditions?

Thanks!!
Wilier Cento1 SR
13.10 lbs (5.95 kgs) w/Enve 3.4-Tune 70/170 & Conti Competitions tubulars
12.53 lbs (5.68 kgs) w/FarSports 24-Extralite & Vittoria CX EVO II tubulars

by Weenie


Thirstyman
Posts: 51
Joined: Fri Oct 24, 2008 3:10 pm

by Thirstyman

your weight is?

Geoff
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Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

I run them 100/110 front/rear. I can't think of a situation for road use where a 140psi pressure would be advisable.

gumgardner
Posts: 3553
Joined: Sat Jan 06, 2007 9:47 pm
Location: Pittsburgh

by gumgardner

I like 9 bar on my tubulars. I've tried others but keep going back to 9. (130psi)

konky
Posts: 839
Joined: Mon Dec 14, 2009 6:26 pm

by konky

I like the feel of 100psi but will usually start with 110psi on longer rides because tubular tires of cause can lose over 10psi on a 4 hour ride. I weigh 65kg-67kg depending on time of year.

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Fourthbook
Posts: 256
Joined: Fri Sep 30, 2011 2:11 pm
Location: Columbus, Ohio

by Fourthbook

I weigh 156 lbs. What are the advantages of a lower pressure?
Wilier Cento1 SR
13.10 lbs (5.95 kgs) w/Enve 3.4-Tune 70/170 & Conti Competitions tubulars
12.53 lbs (5.68 kgs) w/FarSports 24-Extralite & Vittoria CX EVO II tubulars

Geoff
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Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

There are many reasons, but the best reasons are:

1. Improved ride quality;
2. Decreased rolling resistance; and,
3. Better handling.

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Fourthbook
Posts: 256
Joined: Fri Sep 30, 2011 2:11 pm
Location: Columbus, Ohio

by Fourthbook

Geoff wrote:There are many reasons, but the best reasons are:

2. Decreased rolling resistance


Wouldn't a higher pressure lower rolling resistence b/c of less tire-contact on the road and ever-so-slightly less deflection?
Wilier Cento1 SR
13.10 lbs (5.95 kgs) w/Enve 3.4-Tune 70/170 & Conti Competitions tubulars
12.53 lbs (5.68 kgs) w/FarSports 24-Extralite & Vittoria CX EVO II tubulars

RussellS
Posts: 691
Joined: Wed Feb 03, 2010 1:31 am

by RussellS

Fourthbook wrote:
Geoff wrote:There are many reasons, but the best reasons are:

2. Decreased rolling resistance


Wouldn't a higher pressure lower rolling resistence b/c of less tire-contact on the road and ever-so-slightly less deflection?


No. Higher pressure causes the tire to bounce off the road instead of smoothly roll over the road. A tire bouncing up and down on a surface is bad rolling resistance. You want the tire to remain in contact with the surface and flow over it.

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Fourthbook
Posts: 256
Joined: Fri Sep 30, 2011 2:11 pm
Location: Columbus, Ohio

by Fourthbook

Seems counter-intuitive. At some point the lower pressure must > resistence (think of a nearly flat tire). So, where's the cross-over point on nice/smooth roads?

I can understand how < pressure is > comfortable and has better cornering. Does pressure have any effect on tread wear?
Wilier Cento1 SR
13.10 lbs (5.95 kgs) w/Enve 3.4-Tune 70/170 & Conti Competitions tubulars
12.53 lbs (5.68 kgs) w/FarSports 24-Extralite & Vittoria CX EVO II tubulars

Geoff
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Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

It is definitely counter-intuitive. It is one of the reasons that tubulars are faster on the road and clinchers are faster on a steel drum.

Even a 'smooth' road isn't smooth at all. It is the supple nature of the tubular that allows it to roll over and around road imperfections, rather than bounce over them like a clincher. By over-inflating a tubular, you loose some of that suppleness and some of the advantages of the tubular to begin with.

I have never conducted an experiment where I deliberately over-inflated tires, but I can still wear a tubular tire down to the cords before it needs replacing.

Oh, I also believe that a properly inflated tubular brakes better, as the contact patch gets larger with the transfer of weight to the front tire.

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Fourthbook
Posts: 256
Joined: Fri Sep 30, 2011 2:11 pm
Location: Columbus, Ohio

by Fourthbook

Tried 115 psi today. No noticeable difference but that means next to nothing as I was even more dog-meat than usual. Will keep them at 115 for a while.

Would love other opinions/thoughts, etc.
Last edited by Fourthbook on Mon Mar 12, 2012 1:44 am, edited 1 time in total.
Wilier Cento1 SR
13.10 lbs (5.95 kgs) w/Enve 3.4-Tune 70/170 & Conti Competitions tubulars
12.53 lbs (5.68 kgs) w/FarSports 24-Extralite & Vittoria CX EVO II tubulars

kevhogaz
Posts: 225
Joined: Fri Aug 05, 2011 5:18 am
Location: Arizona

by kevhogaz

I'm fat, (230 lbs) and run my Vittoria Corsa CX clinchers at 120 rear, and 110 front. They ride great at those pressures.

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kac
Posts: 361
Joined: Sat Dec 04, 2010 5:31 pm

by kac

Michelin has a weight vs. inflation pressure chart for their tires which I've seen others reference. I'm not at all clear, however, on why the rider weight is the independent variable in that equation.

KAC

by Weenie


Geoff
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Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Each to his own...

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