We know, there’s no such thing as a stupid question. But there are definitely some questions too embarrassing to ask your local shop or riding buddies. AASQ is our bi-weekly series where we get to the bottom of your questions – serious or otherwise.
Have you ever given much thought to your tires while on the trainer or rollers? Companies market specific tires just for trainer use, so there must be something going on with tire wear when you’re sweating it out in your basement. Along those same lines, how does a difference in material of the roller itself affect the tire wear?
That seems to be what Kostas is wondering when they ask, “[does an] aluminum or plastic drum of a roller wear the tires more easily?” To find out, we sent the question over to the team at CycleOps, who replied with a very detailed response…
Based on testing with the plastic and aluminum rollers in the past, we generally get better tire life out of the aluminum rollers. While the reasons for these differences haven’t really been investigated scientifically, the explanations we’ve given are below:
There are two primary contributors to wear on a tire, tire slipping and elevated temperature. Slipping a tire usually stems from not tightening the roller against the tire enough, and slipping a tire on a roller indoors and skidding it on the road outdoors both damage the tire in a similar fashion. Elevated temperature is something that occurs more on a roller indoors than the road outdoors because the tire deforms more when in contact with the small diameter roller than it does when in contact with the flat road. That deformation generates rolling resistance and heat, and causes the rubber to soften and expand. The rubber expands at a different rate than the tire’s Nylon or cotton casing, which causes the two materials to stress each other and in extreme cases even separate. Rapid failures due to temperature are usually caused by over tightening the roller and tire interface, which leads to excessive heat buildup.
So returning to the original question of roller material: The tire has similar traction on aluminum and plastic rollers, so the difference in tire slipping isn’t significant. However, the aluminum roller also cools much faster than the plastic roller (The aluminum roller is roughly 1,000 times more thermally conductive.) So the tire to roller interface stays cooler with the aluminum roller, and causes less heat related wear.
The difference between tires is much greater than the difference between roller materials when it comes to longevity. Inexpensive vulcanized tires outlast expensive hand glued tires on trainers because the glue is more sensitive to temperature. Completely smooth slick tires also typically outlast tires with tread patterns or grooves in them, as the expansion of the rubber with heat causes more damage to surfaces that aren’t uniform in thickness.
That response got us thinking, if cheap tires are better than expensive tires for use on a trainer, why would you buy one of the trainer specific tires instead of just using a cheap replacement or a used tire you have sitting around? So we asked for CycleOps’ answer on that as well, and this was the response from one of their engineers:
I personally use my old road tires rather than a trainer tire. However, old road tires often have grit embedded in the tread which can cause wear on the roller and make the tires slip and wear out quickly. If you’re using old road tires on a trainer, it’s best to clean them and make sure to pick out all of the little pieces of dirt, stone, and glass that are embedded in the rubber before riding.
The main benefit of a trainer tire over an inexpensive generic tire is that the customer can be sure it will be durable and provide the resistance curve that the trainer is designed for. Some tires have much higher or lower rolling resistance and trainer tires will give the speed-resistance relationship that the trainer was designed for. From a durability standpoint, it’s not always easy to know which tires will be durable on a trainer before trying them. If a customer isn’t sure what materials and manufacturing process were used to make their tire, then using a trainer tire is a good way to make sure the tire they use doesn’t wear out quickly after they purchase it.
So there you have it. At least according to CycleOps’ testing, aluminum rollers will generally provide better tire life, but the biggest advantage comes down to the tire itself. If you want the best option for use on a trainer, trainer specific tires are a sure bet. But if you have old tires lying around, feel free to use them for a trainer tire – just be sure to clean them first.
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