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Old 08-28-12, 02:43 PM   #1
weeple2000
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Frequent Flats

I ride on a trainer on occasion, and I prefer to ride out doors. I use a different tire for the trainer because it ruins tires very quickly. I have noticed that I am getting frequent flats on my rear tire, and I believe it is related to transitioning between the trainer and the road. Am I doing something wrong when I am changing my tires? I had to replace the tape in my rim because a hole got punched through near one of the spokes, so that might be a contributing factor. Next time I change my tire I will look at my tubes to see if that is where it is going flat. Could it be bad technique when changing tires?
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Old 08-28-12, 02:49 PM   #2
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Could be that or something else...the key is to check the tube each time. The appearance and location of the leak will almost always point you to the cause.
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Old 08-28-12, 02:59 PM   #3
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next time you mount the tire either line up a reference like the label at the valve, or do as I do, and use a dry marker to put a line at the valve. That way, next time you have a flat, you can locate the leak and trace back a cause, either to a spoke hole if on the rim side, or to a hole through the tire if on that side of the tube.

BTW if you get frequent flats,(like within a day or two, it's possible that you fixed the tube, but left the cause in the tire. Thick tread can hold a small shard of glass, so you don't see it inside the tire, then as you ride, the ground compresses the tire pushing it through the tube.
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Old 08-28-12, 03:14 PM   #4
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next time you mount the tire either line up a reference like the label at the valve, or do as I do, and use a dry marker to put a line at the valve. That way, next time you have a flat, you can locate the leak and trace back a cause, either to a spoke hole if on the rim side, or to a hole through the tire if on that side of the tube.

BTW if you get frequent flats,(like within a day or two, it's possible that you fixed the tube, but left the cause in the tire. Thick tread can hold a small shard of glass, so you don't see it inside the tire, then as you ride, the ground compresses the tire pushing it through the tube.
+1. Could have something left in tire. Be sure to clean inside of tire and see if that helps.
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Old 08-28-12, 05:08 PM   #5
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Additionally the trainer stand is equally hard on the tube. If overtightened the pressure roller can cause such a deep imprint in the tire that the tube and tire's insides skuff/rub enough to abrade the tube. Flats can come from nothing but an abraded tube. It would be interesting to see if your flats periodicness changes if you were to keep the trainer tire and it's tube together and use a fresh tube with the outside tire.

BTW I recommend my trainer customers that the roller is too tight if you never get any slippage under accelerations. Steady state efforts should have no tire/roller slipping but hard efforts will for a few moments. Use full tire air pressures and the least roller pressure you can get away with. Andy.
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Old 08-28-12, 05:12 PM   #6
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I always mount the portion of the tire that indicates the pressure next to the valve on the drive side of the bike, a standard I implemented when I was a service manager. That not only helps with diagnosis but makes it easy for both you and any mechanic that works on the bike to find the pressure. A mark on the drive side of the tube at the valve when you install it provides additional insurance.
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Old 08-30-12, 08:16 AM   #7
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Thanks, i'll look into this next time i get a flat. I believe i still have one or two flat tubes from previous repairs, so if i'm particularly ambitious i'll see if the hole is in a similar spot, although that won't completely help not knowing what part of the rim/tire its from. I guess that narrows it down to 2 parts though.
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Old 08-30-12, 08:48 AM   #8
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BTW I recommend my trainer customers that the roller is too tight if you never get any slippage under accelerations. Steady state efforts should have no tire/roller slipping but hard efforts will for a few moments. Use full tire air pressures and the least roller pressure you can get away with. Andy.
+1 Adjusting the trainer's roller too loose or too tight can damage tires in short order. I set my trainers roller tension so that if I grab the wheel by hand and give it a sharp yank, the tire just slips slightly on the roller. Done that way, tires last as well as they do on the road and don't leave a trail of rubber dust on the floor behind the trainer.

The bike I use on my trainer in the winter is also used reasonably often on the road the rest of the year with the same tire and wear is normal for both applications.
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Old 08-30-12, 07:00 PM   #9
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This is one reason I prefer rollers over trainers. The plastic drum is easier on the the tyre. And the larger diameter caves in and flexes the tyre less at the contact patch. I usually ride over 1000 miles on rollers in the winter and my tyres don't wear any more than the same mileage on tarmac.
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Old 08-31-12, 02:56 PM   #10
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Rollers load a tire differently then a trainer stand. First is that almost no torque is transmitted through tire/drum. A tiny bit to drive the ft wheel but that's pretty minor. Second the rear wheel is sitting on two drums doubling the contact patch. Third the tire/drum pressure is based on your weight, just like on the road, not by an additional device (the hand cranking the roller against the tire). And fourth traditional roller drums are larger in diameter then most trainer stand rollers.

There is a stress factor in how deep the pressure roller presses into the tire casing and how small a diameter the pressure roller is. Tire failure will come FAR faster with deeper indentation (roller pressure) and smaller roller diameters. Car tire manufacturers learned this a long time ago. There is a lot of distruction testing of car tires run against rollers and the failure will happen sooner then the same tire being used on a "flat surface" (road).

But the real reason to ride rollers has nothing to do with tire life and everything to do with ballance, skill, fluidity, smoothness, spin. Trainers kill good form, rollers reinforce good form. But trainers are easy on the mind and rollers require actually learning, so guess why they're so much more popular... Andy
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