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Who runs different psi for front and rear? If so, why?(8 posts)

Who runs different psi for front and rear? If so, why?nigel
Nov 10, 2001 8:32 PM
Who out there inflates their front and rear tires to DIFFERENT psi? If so, is it because of shock-absorption/a softer ride for the front wheel (and less shock on one's hands), or for better handling characteristics? It's interesting to me, and I'd like to hear your views.

My information:
I've been running Hutchinson Carbon Comps at 115 psi front and rear. The "recommended" psi is 100, and the "max" is 125. I've been okay, but when riding through the city (obviously), my hands can get beaten up a bit. Nothing too terrible, but do you think that riding the front at 100 (15 psi lower) would make it noticably more comfortable for me? I weigh in at 130, if that means anything in your equation. I'm 6'6. (Kidding, I'm actually 5'5! Wouldn't THAT be scary?!) I also RAAARELY ever (knocking on my wooden noggin) get flats, and they're never pinch flats--only glass chips.

Big thanks,
Nige
I doRusty McNasty
Nov 11, 2001 6:54 AM
On my 21mm tubulars, I rum 105-110 front, and 130 rear. I weigh 180 lbs.
Sheldon Brown says you should.9WorCP
Nov 11, 2001 9:48 AM
A little more in the back than the front due to the differences in weight distribution. I run the front at 110 and the rear at 120. Does it make a big difference in feel or handling? Nah.
re: Who runs different psi for front and rear? If so, why?tirider
Nov 11, 2001 10:14 AM
On my Conti GP3000s I run 120lbs rear and 105lbs front. In mountain biking running different pressures is the norm. When I returned to road biking I experimented in this venue although this issue of traction obviously isn't as important. To my mind since the weight distribution between the front and rear tires isn't 50 - 50 on a bike changing tire pressures to reflect this make sense. I find I can maximize both comfort and control this way.
Can't feel the diff in skinny tires, but with big ones...cory
Nov 11, 2001 10:18 AM
I used to fiddle around with it, but at 220 lbs I can't go too low with skinny tires or I pinch flat. Since I started using 32mm tires, I run 90-95 in front, 100-105 in back for a little more cush.
How about just lower?Kerry Irons
Nov 11, 2001 11:38 AM
For someone as light as you, you could drop down to 100 psi, gain a lot of comfort, still not worry about pinch flats, improve traction (more rubber on the road), and probably never notice any difference in rolling resistance.
Interesting, Kerry. I'll certainly try it.nigel
Nov 11, 2001 12:03 PM
Before my ride tomorrow, I'll deflate the tires to 105 rear and 100 front and see if I feel a difference. (15 psi less in front should make a diff. I don't know why I didn't think of it 'til you suggested it--guess I was just in the habit of trying to maximize my speed by hardening up the tires.) You're right, though: since I'm a smaller rider, the tires don't need as much air as I've been putting in them.

Maybe I'll wind up exclaiming "F**KER!" a lot less on each ride, since the tires will be absorbing more of the hard bumps on these streets instead of my fork/headset and/or hands). :)

Good advice, mate. Cheers.

Nige
used to .... but seldom do any longerCT1
Nov 11, 2001 6:16 PM
My Dale cadd5 and Star forked Colnago MXL used to beat the crap out of me so I would run 10-15# less in the front. The worst was the Dale. Damn, the front end on that thing was like a jackhammer on some of the crappy roads I use.

My current bikes, TCR ONCE and LOOK KG281 are schweeeet riding frames so I can run 120# both ends still keep the fillings in place. I expect the same ride quality from the CT1. I'm 147# and could probably drop the front a tad and not take a performance hit. I use Veloflex Pave tires which are a bit smaller than their rated 22 size. They ride pretty good actually and I'm getting about 1500 miles on the rear.

IMHO, the fork has the most impact (neglecting tire pressure obviously) on front end ride quality. Wheels can have a surprisingly big influence on ride quality too. Some of the hammerheads around here don't seem to know this fact.

YMMV
JohnG