When I bought my set of Williams System 30's I bought a set of Schwalbe Ultremo R.1's and Michelin Pro Tubes to go with them.

I've noticed that even when inflated to 120psi that when sitting on the bike the rear tire is noticeably deformed at the contact patch. While riding I look down and sometimes do a double-take to be sure it isn't flat.

I weigh 150lbs, so while I'm obviously too fat for this sport, I'm certainly not a clyde.

This has got to be affecting rolling resistance. I inflate inside with AC before going outside. I thought air expands in the heat, so that shouldn't be an issue.

I check pressure before every ride and ride almost daily. The lowest I've seen has been around 105psi. This leads me to believe that the tube isn't the problem as I'd expect far lower than 105psi if there was a leak.

Anyone have any ideas? Is this normal? Do the Ultremo's suck? Should I just chalk this up to the heat? Could it be the tube?

What do you mean by deformed? A little bulging is normal for a tire when there's weight on it.

Really at 150 lbs you only need to be pumping your tires up to about 100 psi if you are running 23s.

If your tires don't deflect, you might as well be riding solid rubber.
I've heard the figure of approximately 1/6th tire width is about the right amount of deflection thrown around. I don't know where that comes from, though.

I started at 100psi but went up to 120psi to see if it was a pressure issue. I don't always run that high.


I expect some deflection, but this 'seems' abnormal to me, hence the post.
I would guess it is more like 1/3 of the tire width. I'll take a picture and post it tonight after work.

Picture?