Re: [CR] Strong, Longlived Wheels

(Example: Framebuilders:Richard Moon)

Date: Wed, 26 Aug 2009 22:37:41 -0700
From: Pacific Coast Cycles <paccoastcycles@sbcglobal.net>
To: <classicrendezvous@bikelist.org>, John Hurley <JHurley@jdabrams.com>
In-Reply-To: <249DDD9704676C49AE6169AE3D2D9F4ECDB87F@Exchange-SVR>
Subject: Re: [CR] Strong, Longlived Wheels


I agree with John Hurley that much of what we understand is more alike than the way we end up putting it into words.

There is some vaguely worded stuff in there for sure, but something that isn't in any way vague is off base by enough that I feel it needs to be addressed. John says that when it comes to handling potholes the main factor would be rim cross section. Not even close. It is easy to understand that a tire is the first thing that meets the edge of any obstacle. If we overcome the tire's cushion, which is to say, we bottom it out and the rim is thereby taking the blow, the cross section of the rim won't make much difference.

Most rims for the last 25 years have been very "hooked bead" in design. They normally respond to edge overload by dinging the hook area. It is soft enough, admittedly because of its cross section that in mild cases, it will save the overall section of the rim from deforming. Still, it will cause uneven braking. A thicker bead catching section, typically used on single wall rims will usually deform the whole rim even in a mild impact.

One way to illustrate the point that it is tire cross section and not rim cross section that has great effect on impact resistance is the mountain bike tire/wheel combo. If you haven't ridden both, you can't be expected to understand this example, but just put a real skinny tire on your skinny mountain bike wheel and do your regular ride intensity and you will have a graphic example of what the tire does.

Chuck Hoefer
Vista, California USA


--- On Wed, 8/26/09, John Hurley wrote:


From: John Hurley 

  I mean, shouldn't the question should be which wheel performs better given the same tire?  When it comes to handling potholes, I would think the main factor would be rim cross-section.

 With all these variables in play, it is no wonder that theories abound, some of which border on superstition.

John Hurley
Austin, Texas, USA