Tire vs rim pressure recommendations.

Especially for light weight issues concerning cyclocross / touring bikes & parts.

Moderator: Moderator Team

Post Reply
jfranci3
Posts: 228
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

I have a Stans Grail wheelset that I'm happy with. I just bought a set of 35c Clement USH 120s http://clementcycling.com/ush. The rims say 45psi max for 32c, the tires say 55-90psi on the sidewall :noidea:

http://redkiteprayer.com/2015/08/clemen ... ush-tires/
Image

Before I noticed the 45psi guideline on the sticker, I ran Bontrager 32c @ 65psi without an issue. For the time being I'm running these at 50psi.

I guess my worry is that I'm going to wear out the sidewall on the tire as it rubs against the rim.

Any recommendations?

simoncx
Posts: 93
Joined: Sun Nov 15, 2009 12:27 am

by simoncx

55-90psi seems like a lot for a 35c tire, I ran conti semi slick cx tires which are more like 31-32c in the winter and I usually ran them 50-55 psi on the road without a problem, but it depends how much you weight.

by Weenie


mattr
Posts: 3456
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

It's not the tyre sidewall wearing out that you need to worry about, it's blowing the tyre off the rim.

And as size goes up, max pressure comes down. So you might be ok with 50 psi, if the tyres are nice and tight and tubeless ready beads(?) if not you might find yourself skating down the road on the rim with the tyre wrapped round the fork crown........

Do you really need that much air? And grails are (effectively) lightweight CX racing rims. Not really designed around high pressure use (most CX riders will be running ~30psi on tubeless)

mattr
Posts: 3456
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Just had a proper look at the website, running normal tyres tubelessly gives you the 45 limit at up to 50mm wide, tyres with tubeless beads can run up to 115psi but only 32mm wide.

So you'll probably be ok at 50psi with 35c normal tyres run tubelessly. At least, i'd not panic.

It's still quite a lot of air ;)

thprice
Posts: 238
Joined: Sun Jul 17, 2011 6:34 am

by thprice

I have been running Grails for the past 2 years, 30mm tires @ 75 psi and 35mm tires @ 50 psi. They have been great, no issues and plenty of abuse.

kafreeman
Posts: 39
Joined: Thu Jul 23, 2015 8:46 pm

by kafreeman

Probably ok, I am curious to the reasoning behind it.

Is wonder if it is due to tire deflection with wider tires on the rim, 23mm is good to 116 psi.

Sent from my SM-G935V using Tapatalk

User avatar
jcrr
Posts: 87
Joined: Wed Nov 30, 2011 4:36 am
Location: Seattle, WA

by jcrr

You may want to take a look at the table some of us compiled here:

viewtopic.php?f=4&t=136644&p=1297232#p1297232
"If it ain't broken, it could be lighter"

User avatar
wheelsONfire
Posts: 1784
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

I agree with you on the info and usage. I wrote Clement and asked as i noted i ran pretty high pressure on my Clement tires (tubeless).
However, they recommended even higher pressure than i used.
I recently cracked a rim from a so called "blow off". So now i am certainly more careful inflating tires on alu rims.
My carbon rims handles max 115 psi and the alu, max 45 psi.
I would guess you kind of see when you inflate, when you start to run well enough pressure to ride safe.
But as Mattr says, it pends on the size of the tire to.
Bikes:

Ax Lightness Vial EVO D
Paduano Racing Fidia
Open *UP*
https://opencycle.com/showcase/the-xplo ... eelsonfire

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post