Trainer issues. It is literally burning rubber.
 

I have a hand-me-down magnetic trainer, and I put a towel underneath because I've heard it keeps the noise down a bit, and I live in an apartment building. When I spin at a normal pace everything seems fine on the trainer, but when I change a gear or two and do an interval for a minute or so I notice a smell of burning rubber. I didn't realize that the tire was actually being worn down this much - I've probably put on 5 hours on the trainer in the past 3 weeks, total.

The tire is touching the rear mechanism just enough so it doesn't skip but still feels like there is a lot of resistance. If I try to manually move the tire it will move only 1/4 to 1/2 of a turn before coming to a halt. Is there anything else I can do or is this normal?

Also, the magnetic part of the trainer doesn't work anymore, so to get more resistance I have to change gears on the bike. I'm always in the middle ring, and move from the middle to the smallest cog in the rear to change the resistance.

Any way to change this? Would a new trainer solve the problems of the burning/wearing down of my rear tire? Should I stop using the trainer?

in the second pic, is that shredded bits of rubber all over the floor? This is not normal. You can get a new mag trainer pretty cheap.

Tires wearing out on trainers with small diameter bars where the tire contacts is a well known problem. If backing off the tension doesn't help, one solution is to use old tires that you wouldn't use out on the road. For example one with too many punctures or a slit sidewall. There are tires made especially for trainers, but I usually have enough old tires to last the winter.

Also you might want to consider an old rear wheel to use only on the trainer. That way you can swap it out quickly when the weather gets better. Heck I even had a bike with a cracked frame for trainer duty at one time.

A new trainer may help. Also consider rollers as they don't wear out tires due to large cylinders touching the wheels.

Agree with Seymour. Those shredded rubber bits are not nromal. And there seems to be no evidence of wear on the aluminum roller contacting the tire.
Are you sure the tire is not rubbing anywhere else when you are on the bike? It almost looks like the tire contacts the front crossbar in the second pic.

@seymour1910 and @mvnsnd, yeah it's shredded bits of rubber - I haven't noticed it before last night. I'm not going to buy a new trainer this year, hopefully in 6 weeks it will start to get warmer and I can just ride outside. I will check to see if the tire is rubbing anywhere else, thanks for the suggestion.

@JerrySTL these are my stock wheels and tires that came on the bike, I just got Vuelta Corsa Lite wheels and Continental GP4000 tires, just need to buy tubes then I'll be totally set with a new set of wheels that I will use outside, and when I start doing Crits in March. These will be a backup pair, but I'm sure even with the wear on the back tire it will be fine to ride outside unless it's wet. I wonder if there will be less rolling resistance due to the smoothness of the rear tire.

I bought my friend a Minoura Rim Drive trainer for Christmas and he likes it. Since the mechanism engages the rim, there is no tire wear issue. Has a bit of resistance adjustment to it as well. There were a few floating around CL here, ended up paying $90 for the one I bought.

I was thinking that as well.. Looks like a black mark on the front crossbar in the 2nd picture? Is it contacting the frame there?

Man, that tire is hitting something when you are sitting on the bike. My bet it is the first crossbar, because the rubber bits are right after it on that towel. If the rubber was primarily on the back of the trainer wheel, I would say that was binding and destroying the tire, but it doesn't look like any rubber is staying on the trainer drum wheel, and there isn't a ton of rubber out the back.

I would check the arms that hold the front crossbar and see if they are warped, bent, or the screw holes are elongated enough to put your bike onto that crossbar.

I had this exact same problem when i first starting using a trainer. Try adjusting the resistance by pushing the tension knob on the back to push the trainer roller more onto your tire. The first few times i used my roller, i shred so much tire, i was finding it weeks later. I adjusted the trainer roller and it eliminated that problem.

This worked for me on my Cycleops Trainer and it might not work for you. But just thought i'd offer my experience.

Definitely something looks odd here. However, despite that, I've heard, and experienced myself, that prolonged use on a trainer will wear out the tire prematurely. Might be worth your while to go to your LBS, buy a lower cost wheel, outfit it with the proper casette and rubber, and use that when you're on the trainer.

I'm on winter 3 on my trainer (a fluid one) and put an old puncture prone tire on for trainer use, expecting rubber bits, but other than making the tire shiny, there hasn't been any of what you've had and I'm still using the same tire. I'd guess I ride at least 40 or 50 hrs per winter so diff trainers certainly treat tires differently.

So you make it tighter on the wheel so there's more resistance? I thought the idea was to make as little contact as possible with the trainer because if it's tight the tire can get flat spots. That's what I read on an old thread.

Continental makes a Tire.. for using on those type of trainer-stands..

Typical reccomendation is 1-2 turns of the tension screw after the tire contacts the roller. It should be tight enough that a sudden movement of the wheel doesn't cause the tire to slip on the roller. Also check that you are runnning normal tire pressures.

Yeah. You don't want the tire slipping, that's what causes fast wear and shredding. You need enough tension to prevent slipping.

What about this trainer do you think will be different on a new trainer and that will prevent shredding?

Is it even necessary to use the tension adjustment knob. My Nashbar Fluid Trainer doesn't even have one. My weight is what keeps the tire pressed against the spindle.

my cycle-ops has a tension nob and without adjusting it the bike will not spin the drum; likely this is trainer/brand specific.

Inflate tire to max rated pressure. Adjust tension so that a quick, firm pull on the wheel with your hand doesn't cause the tire to slip on the roller. When adjusted correctly, there will be some significant pressure between the tire and roller. Release the tension as soon as your session on the trainer is done (to avoid flat-spotting and heat soaking the contact spot on the tire). Trainer use may still wear the tire faster than road use, but it shouldn't be shredding it the way the photos show.

I suspect earlier posters were right about contact with the front cross-member when the rider's weight is on the bike. Perhaps only on a portion of the pedal stroke. There has to be some kind of rubbing to shed that much material in that short a time.

you need to have enough contact pressure to create traction so that it doesn't slip. Read the instruction manual for any trainer you can find and they all say to basically screw the knob in until the drum just makes contact then turn it 2 or 3 more full turns.

Also, mag stuff doesn't just stop working, unless it's literally missing parts. The fact that you can be in your middle ring and that's enough resistance is proof that it's working.

I guess it's also possible that you have a really cheap and\or defective tire.

They're cheap because somebody with a brain figured out that folks are trashing their rims with the rim drive and went to the tire for the resistance.

Could you elaborate? I'm no expert on trainers by any means, but I am in my 4th year of a mechanical engineering degree and can't see how such a trainer, set up and used properly, would cause rim damage. I suppose that improper tension on the drive wheels or bad bearings and excessive friction/wear on the brake tracks might cause an issue, but it seems to me that this would fall under the category of improper use/setup.

I give my Kurt Kinetic Road Machine 5 full turns of the knob after the drum makes contact with the tire. That is what they recommend.

Then you should understand that friction causes wear and heat. A tire will square off in fairly short order and then very little afterwards. There is no need for a trainer specific tire. I've had the same tire on my trainer for 5 years. There is wear of course due to friction and it will fail eventually but it is minimal. In the rim drive, there is friction on the brake surface which is not good for the rim. Don't know why anyone would choose the rim drive over a trainer where the resistance is on the tire. Do a search and you'll find that most on the market put the resistance on the tire.

This is fundamentally true, but I don't think the situation is as simple as that. Without getting into the nitty gritty of it, it seems to me that rolling friction involved in the use of a rim drive trainer wouldn't cause any more brake track wear than regular braking. I also think the mechanical properties of the materials of the two parts in contact must be considered. The resistance wheels on the trainer I bought my friend seem to be made of a fairly pliable rubber or urethane which I think would wear out before the aluminum in the brake track (which is likely surface treated to provide better wear resistance) did. A good analog is that of a tire drive trainer. Over a long enough time period for significant wear to occur, does the tire or the drum wear out first? Granted the drum likely isn't aluminum, but the basic principle is the same.

I dunno, this is all supposition without any data to back it up, but it makes sense to me. I'm sure there are plenty of great tire drive trainers out there which don't chew up tires when used properly, but that's not to say that the rim drive concept is fundamentally flawed and that "somebody with a brain" should throw theirs in the trash and run to the LBS to spend cash on a tire drive.