Bike and Cycling Forum > Bike Forums > Road Bikes > Could my trainer be twisting my frame? (not a general trainer concern...just mine.)


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Old 01-29-2013, 05:08 AM   #1
lakawak
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Could my trainer be twisting my frame? (not a general trainer concern...just mine.)

I noticed immediately that my bike had a slight lean to it when I put it on my trainer. But other than that, it was fine. But after about 2 1/2 weeks, I noticed that my tire is now nowhere near on the center of the resistance unit. And it is impossible to get it to be center. It is so bad that even the slightest wobble while riding causes the tire to rub against the side, which obviously will shred the tire in no time.

When I tried to readjust it, I noticed that the problem is with the arms of the trainer. It is a Nashbar adjustable Magnetic Trainer with the gravity stand that is only supported in one spot that can freely swing down to the resistance unit so there is no need to adjust the resistance unit. (nor can you.) It appears as if either the two "arms" of the frame are unbalanced or the cups that hold the skewers are. When I have my bike level and put the one side in the left cup, the right cup as a good 3/4 inch above my skewer. So the only way to get it in is to lean my bike to the left, which is why the tire goes all the way to the edge.

My concern is that, while there was a slight lean before, the tire originally was fairly centered. Maybe not dead center, but there was plenty of room between it and the side of the resistance unit. So, I am getting concerned that either the trainer frame or my bike frame is twisting ever so slightly with every ride? Unfortunately, we are in the middle of a really cold snap and lots of slush and ice on the ground so I can't even test of for 50 feet or so outside to make sure everything is fine.

Anyone have a similar problem and should I be concerned?

You can see in the picture just how far to the right the tire is. I am amazed I haven't had my tire shred explosively yet since I have had it rub as I was going over 30 MPH and the side of the resistance unit as some rough, maybe even pointy edges on it.



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Old 01-29-2013, 10:21 AM   #2
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OK...I am a moron...the resistance unit moves along that back bar. I gave it a quick try before and it didn't seem to move so I thought it didn't. I don't remember having to center it to start.

However, I think my concern still stands. Regardless of it being centered or not, my bike is leaning which it doesn't do when I am riding. So could that cause some torque on the dropouts? After all, I am having to compensate for the lean by leaning a bit in the opposite direction while riding. so my body weight is twisting it in the opposite direction.



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Old 01-29-2013, 11:10 AM   #3
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Are you sure you have the bike positioned correctly? Or is the surface level?

As long as you are not standing up and hammering, I wouldn't be too concerned of twisting your frame. You can also try putting the bike and trainer on those interlocking workout/play mats that you can buy. They are foam and will allow the unit to move a few millimeters. Plus they save your floor from any sweat you drip or water you spill.

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Old 01-29-2013, 11:53 AM   #4
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Quote:
Originally Posted by zero3one View Post
Are you sure you have the bike positioned correctly? Or is the surface level?

As long as you are not standing up and hammering, I wouldn't be too concerned of twisting your frame. You can also try putting the bike and trainer on those interlocking workout/play mats that you can buy. They are foam and will allow the unit to move a few millimeters. Plus they save your floor from any sweat you drip or water you spill.
heh

outside of the wood floors, looks like what i've got setup in my basement now.

mats from dicks or sports authority?

I think I've got to stick something a little more substantial under mine as they're on top of carpet, and I'm getting a bit concerned my rear tire will make contact as the mats sink in/wear into the bottom of the trainer
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Old 01-29-2013, 12:25 PM   #5
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What skewers are you using on the bike? I had a similar thing happen with my Colnago the first time I put it on the trainer. On mine, the stationary cup on the trainer fits the drive side skewer head just fine, but the cup on the adjustment crank does not as the skewer head is larger and would not go into the cup properly. This was causing the rear wheel to torque some when under a load. I have to change over to the skewer that came with the trainer whenever I use it. I keep saying I'm going to get different skewers, but every time I get to the LBS, but since I don't use the trainer that often I forget all about it.

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Old 01-29-2013, 03:20 PM   #6
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What skewers are you using on the bike? I had a similar thing happen with my Colnago the first time I put it on the trainer. On mine, the stationary cup on the trainer fits the drive side skewer head just fine, but the cup on the adjustment crank does not as the skewer head is larger and would not go into the cup properly. This was causing the rear wheel to torque some when under a load. I have to change over to the skewer that came with the trainer whenever I use it. I keep saying I'm going to get different skewers, but every time I get to the LBS, but since I don't use the trainer that often I forget all about it.

I figure I'll just leave the one from my trainer in for solo rides, and add on the hitch adapter for our burley as necessary.

the skewer that came with my cyclops is just as light as the stock one on my GT
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Old 01-29-2013, 05:35 PM   #7
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You will get a lean if it is on carpet since you are over padding which has give to it.

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Old 01-30-2013, 08:41 AM   #8
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Quote:
Originally Posted by John_V View Post
What skewers are you using on the bike? I had a similar thing happen with my Colnago the first time I put it on the trainer. On mine, the stationary cup on the trainer fits the drive side skewer head just fine, but the cup on the adjustment crank does not as the skewer head is larger and would not go into the cup properly. This was causing the rear wheel to torque some when under a load. I have to change over to the skewer that came with the trainer whenever I use it. I keep saying I'm going to get different skewers, but every time I get to the LBS, but since I don't use the trainer that often I forget all about it.

I'm using the skewer that came with the trainer. It fits in on both sides OK...it just doesn't line up level. When the bike is perfectly vertical, the right side of the skewer is way below the cup, so I have to lean the bike to bring it up

Like I said, it is not as bad as I thought it was. Somehow the resistance unit moved a bit on the base. But even centered it is still not allowing the tire to be centered, though it is well away from the edges. There is still that slight, but definitely noticeable lean in the bike though.

I was relieved when I realized the resistance unit had moved. At the very least, it shows that it is not getting worse. That was my biggest fear...that by compensating from the lean by leaning the other way, I was twisting the frame, causing it to basically compound the problem. I was worried if that is what happened after just 25 rides, then by the time the warm weather came around, I'd be in great riding shape, but without a bike to ride.

I'm just going to keep a close eye on it to make sure it ISN'T getting worse.
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Old 01-30-2013, 11:02 AM   #9
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Also, get a trainer tire. Trainers go through tires like no tomorrow. I just got one and it's doing very well.

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Old 01-30-2013, 10:44 PM   #10
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I am just using an old tire. I tend to keep a couple old tires around as an emergency back up just in case I have a major problem with my current ones that makes me need a new one right away, before I have time to order one online. (My main LBS has an over 400% markup on things like tires...not an exaggeration. So I stay away from them unless I absolutely have to.) So I have no shortage of spares that I don't mind wearing all the way out. Usually they are still fine, but I stopped using them after a couple flats in a short period of time. Most likely, it was just bad luck, but I tend to replace them anyway. (And on the trainer, I don't have to worry about nails, or those damn emergency flare wire "stands" that never get picked up after a car accident!) But so far, I haven't noticed anything. It doesn't seem to be wearing at all really. And definitely no rubber shavings underneath which I was expecting based on what I read on various message boards.

I think that is one of the supposed benefits the "gravity" style trainer. I never have to worry if I have the resistance wheel a little too tight to too loose which is what seem to be the main cause of tire shredding.

I figured since I just got the trainer in January, about halfway into the off season, I'd take a wait and see attitude before going and buying an expensive trainer tire. If this year is anything like last year, I only have about 5 weeks before I can get back on the road for real. I got about 400 winter miles in last March. Once that happens, my hybrid goes on the trainer for rainy days.



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