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Squared rear tire and crashes(5 posts)

Squared rear tire and crashesteamsloppy
Jan 26, 2003 12:03 PM
What is the change in handling caused by the squaring of the rear tire?

I dumped my bike in a turn last night while making a left turn. After the apex of the turn, my rear tire followed some path other than the front tire: the rear ended up on my right, like a single fishtail-like action. I counter-steered, but had to bail before I hit the curb. Road rash on my ass and bruised hands.

Something like this happened two years ago: I stayed on the bike for at least two complete fishtails back then. That time I broke a collar bone and had I concussion.

My rear tire is squared (over 4600 miles). Could this be the cause?

I have noticed over the last couple weeks that the bike fishtails a little if I hit a bump with one hand on the bars. Never noticed that before.

No crashes on this frame till now. The wheels are perfectly true. The headset seems perfectly tight. Tire pressure within 5 psi of where I pumped them (135 / 145). The bike seems perfect even after the crash, except for a scratched pedal , seat leather, red paint and a scratch on the front rim where it hit the curb (apparently a no parking zone).

That rear tire just glares at me as the only thing questionable about the bike.

What is the handling change / characterisitics of a squared rear tire?
re: Squared rear tire and crashessiclmn
Jan 26, 2003 3:34 PM
Your tire pressure is so high that the tire is loosing it's grip on the road when you push it in the turns. Go to 115 psi like most of us ride at.
Not likely related unlessKerry Irons
Jan 26, 2003 7:01 PM
Unless you've worn down to the casing, the rubber is deflecting a lot under your weight and cornering forces and you still have the same size contact patch (simple physics). Another possibility is that the tire is a couple years old and the rubber is starting to deteriorate (cracking, crazing, crumbling). Per the other poster, if the tires are relatively new, you've running too much pressure to get good cornering grip unless you weigh a lot. Most tires are not very supple at 140 psi.
Agree, too much psi. 4600 miles? Replace it!! nmSpunout
Jan 27, 2003 4:32 AM
re: Squared rear tire and crashescommuterguy
Jan 27, 2003 6:11 AM
I have posted here previously that I noticed the handling on my bike getting "squirrely" as the rear tire wore away. Swapping out the old for new rubber in the rear solved the problem.

I would second the others' advice about tire pressure; other discussions here (I think) have concluded that rolling resistance doesn't decrease as PSI increases over 110 PSI (typical road tire, eg Michelin Axial Pro).

Also, IMHO, anyone testing the limits of adhesion on a road bike should be riding newer rubber than you were. $100/pair is a lot, but it is a lot less than new bike, broken bones cost. Again, just MHO.