My Tire Mounting Problem
By Steve Litt

On my Gary Fisher Tarpon, I switched from an alloy rim to a steel rim on my rear wheel, and now I cannot center the tire, so my tire has an annoying low spot that thumps on every revolution and slows me down. The tire is a Continental Town and Country, 26" by something like 2.0", rated at 65PSI, and I had no trouble with centering or low spots when using the alloy rim equipped wheel. When I switched to a wheel with a steel rim, the centering problems appeared. I've tried the following attempted solutions:

Pumping it to 15 PSI and attempting to manually adjust the tire all the way around
Applying soapy water all the way around both sides between tire and rim, and pumping it up to 70PSI
Pumping it up to 90PSI and hoping the low spot would "pop out"

None of the preceding worked.

I suspect the root cause may be the configuration of the interior of the rims. The alloy rim had a "ledge" that prevented any part of the tire from sinking so low as to create a low spot directly opposite. It also was straight up and down where the bead sits. On the other hand, the steel rim has no "ledge", so it doesn't automatically center. Adding to the problem, there's a tiny lip on the interior of the steel rim near the rim's outer edge. See the diagrams below:

Alloy Rim	Steel Rim

The alloy rim has a ledge to prevent the bead from sinking too far into the rim. Such sinking would cause a tire low spot 180 degrees around the wheel.	The steel rim has no such ledge. Further complicating the problem are the lips, which make it very difficult to "pull" the bead outward. The steel rim is also about a half centimeter wider than the alloy, which might possibly have something to do with it.

I really like my steel wheel. It has a bolt on axel to make theft less convenient. It's strong and sturdy. It's cheap enough that I can replace it on a yearly basis (my original equipment alloy wheel lasted less than a year, and replacements are $59.00 instead of $25). Can somebody tell me how to properly seat my 65 PSI Continental Town and Country tire into my new steel rim?

Thank you.

Answer

The answer was to purchase a Nimbus Armadillo tire. It holds up to 100 pounds, and centers like a dream if you pump it up to about 8 PSI and then hand center.

Steve