New posts

Tire Pressure question

Feb. 9, 2020, 4:30 p.m.
Posts: 1216
Joined: Nov. 8, 2003

Specifically do 29" tires take lower psi than 27.5" for equivalent feel?

23psi, 26psi I have determined as my perfect psi on the 27.5 all-mountain bike for fast-ish enduro-y riding. (190lb rider, E13 front, DD Schwalbe rear).

New to the 29er game and haven't pinned down 29" pressures yet. Does one typically go down in pressure for 29 vs 27.5 as they are larger volume?

Sorta feeling like 21, 24 feels right on my gingerly ridden short travel 29er with Maxxis EXO tires, but man that seems low...

https://nsmba.ca/product-category/memberships/


 Last edited by: Hepcat on Feb. 9, 2020, 4:57 p.m., edited 1 time in total.
Feb. 9, 2020, 6:01 p.m.
Posts: 2121
Joined: Nov. 6, 2005

Great question... I think for a similar tire diameter in 29 the volume per contact patch area doesn't change much... not sure I worded that properly?   I would run similar pressures, maybe a touch lower on  the 29s...

Feb. 9, 2020, 6:02 p.m.
Posts: 167
Joined: Dec. 6, 2017

Don't have a comparison between the 2 tires. I'm 185 lbs, 23psi front (29 x 2.5 DHF), 25psi back (29 x 2.4 DHR2). I tried 23 psi in my rear tire and was getting rim strikes ( one nasty dent). 25psi seems to be good.

Don't know if that's helpful or not!

Feb. 10, 2020, 12:49 p.m.
Posts: 374
Joined: Sept. 10, 2012

If the tire has the same size casing and is on the same width rim I'll use the same pressure regardless of wheel size.

Feb. 10, 2020, 2:52 p.m.
Posts: 308
Joined: Feb. 24, 2017

Posted by: Vikb

If the tire has the same size casing and is on the same width rim I'll use the same pressure regardless of wheel size.

Yes. That’s physics. That was my finding too. While the larger diameter tire does have more volume I don’t think it is enough of a difference to matter.

Feb. 10, 2020, 4:56 p.m.
Posts: 1216
Joined: Nov. 8, 2003

Posted by: Vikb

If the tire has the same size casing and is on the same width rim I'll use the same pressure regardless of wheel size.

Rim width is a good point. Hadn't thought of that.

Forum jump: