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From: Frank Krygowski <frkrygow@sbcglobal.net>
Newsgroups: rec.bicycles.tech
Subject: Re: Speed, load & temp limits for bike tires
Date: Wed, 19 Mar 2025 21:12:31 -0400
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On 3/19/2025 1:31 PM, Radey Shouman wrote:
> Frank Krygowski <frkrygow@sbcglobal.net> writes:
> 
>> On 3/15/2025 2:50 PM, bp@www.zefox.net wrote:
>>> Is anybody aware of testing results for the speed, load and
>>> temperature limits of bicycle tires? Something like the DOT
>>> specs for load range and speed rating for auto tires, but
>>> applied to bicycle tires? It's obviously not relevant to
>>> bikes apart from tandems engaged in downhill racing. Perhaps
>>> not even that.
>>> This is an admittedly obscure question, but maybe there's an
>>> answer lurking somwehere I've not found. Probably manufactureres
>>> do it as part of design and production quality control, but whether
>>> results leak into the public sphere is unclear. I ask because I have
>>> a very nice bike cargo trailer (cycletote) which I've pondered
>>> attaching to a small motorcycle. It isn't something I'd do
>>> under normal circumstances, of course. Merely wondering what
>>> might be possible in a pinch.
>>
>> I'm not aware of any such data. I very much doubt temperature is a
>> significant variable. In the past, this group has had extensive
>> discussions of maximum temperatures of rims and how they affect tire
>> integrity, but all that was in relation to rim brakes heating on
>> super-long descents. A trailer would see none of that.
> 
> At highway speeds a standing wave occurs right after the tire contact
> patch.  In the frame of the tire, of course, it travels at the ground
> speed of the vehicle.  Repeated deformation of the tire carcass results
> in heating the tire and can result in failure, which is why car tires
> have a speed rating.  Bicycle tires are not so rated.

Since tire rolling resistance measurements by rotating drums are 
measuring mostly the hysteresis losses within the tire, we can probably 
do some approximation calculations of the heat input. But decent 
estimates of heat loss would be much harder, given the complexity of 
forced convection. And you'd need both input and output to get a handle 
on temperature rise.

I'm not going to bother with numerical estimates, because I'm pretty 
sure it's a non-issue.


-- 
- Frank Krygowski