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Discussion Starter #1
Well? Should I?

I have a C'dale R700 set up with Velomax Orion wheels, Armadillo tires, 9-sp 105. I also have a sweet vintage Schwinn Super Sport single speed (38x17) with cheap-o 28c tires on it. Which would be a better choice for doing spin intervals (to build speed)?

I sorta hate to put the fancy road bike on the trainer, but it has gears. The SS doesn't. Plus the Schwinn didn't cost what the C'dale did. Any guidance is welcome.

Thanks
 

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Downshift said:
Well? Should I?

I have a C'dale R700 set up with Velomax Orion wheels, Armadillo tires, 9-sp 105. I also have a sweet vintage Schwinn Super Sport single speed (38x17) with cheap-o 28c tires on it. Which would be a better choice for doing spin intervals (to build speed)?

I sorta hate to put the fancy road bike on the trainer, but it has gears. The SS doesn't. Plus the Schwinn didn't cost what the C'dale did. Any guidance is welcome.

Thanks
Replace the skewer with a $5 one from the bike shop, and ride the cannondale. You're not going to hurt it a bit putting it on the trainer, and the choice of gears will help you customize the workout (like spinning recoveries.)

Any bike that would be damaged by being on a trainer would be positively life-threatening on the road.

Where did we get this urban myth that trainers damage bikes? As many times as the question gets asked, no one has ever come up with so much as an "I know a guy who's uncle's cousin's mother's best friend's aunt heard about a guy who..." and yet the question keeps getting asked.

For once and for all, trainers stress a bike far less than riding over the most benign of road hazards at speed. It's simply not a problem. If riding a bike in a trainer would torque a frame that much, we couldn't possibly keep a bike upright and on the road without the rear axle connected to something solid.


FWIW, intervals indoors might not be your best training move. If you do intervals without a sufficient base, they're somewhere between useless and counterporductive. As it sounds like you're just now getting around to mounting up a trainer, it sounds like your base might be lacking. Maybe you want to consider using the trainer to get your base set, so you can hit quality intervals outside when the weather turns. Takes away some of the percieved threat to the bike, too. Of course, for base building, you could mount up the old bike if you wanted, too.
 

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danl1 said:
Replace the skewer with a $5 one from the bike shop, and ride the cannondale. You're not going to hurt it a bit putting it on the trainer, and the choice of gears will help you customize the workout (like spinning recoveries.)

Any bike that would be damaged by being on a trainer would be positively life-threatening on the road.

Where did we get this urban myth that trainers damage bikes? As many times as the question gets asked, no one has ever come up with so much as an "I know a guy who's uncle's cousin's mother's best friend's aunt heard about a guy who..." and yet the question keeps getting asked.

For once and for all, trainers stress a bike far less than riding over the most benign of road hazards at speed. It's simply not a problem. If riding a bike in a trainer would torque a frame that much, we couldn't possibly keep a bike upright and on the road without the rear axle connected to something solid.


FWIW, intervals indoors might not be your best training move. If you do intervals without a sufficient base, they're somewhere between useless and counterporductive. As it sounds like you're just now getting around to mounting up a trainer, it sounds like your base might be lacking. Maybe you want to consider using the trainer to get your base set, so you can hit quality intervals outside when the weather turns. Takes away some of the percieved threat to the bike, too. Of course, for base building, you could mount up the old bike if you wanted, too.
i agree with all of that, great response. base training is definitely an important first-step before you start doing intervals. hook up ther ss for a bit, spin for some good long sessions a couple times a week for a few weeks at least, then start introducing intervals maybe once a week, not every ride. there are other options for trainers, including an indoor trainer-specific rear tire from continental, a lot of riders get a really cheap rear wheel set up with a compatible cassette for their multispeed bike-saves changing tires, dont worry about skewer wear, etc.
as danl said, althoguh your bike might rock around slightly and seem rigid when its on your trainer, it definitely is not being damaged. if youre worried about your bike getting damaged on the trainer, you'd better stop it on the road and walk everytime you see a patch of gravel, a tiny pot-hole or a shallow curb. heck, even a pine needle. happy riding!
 

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Discussion Starter #5
danl1 said:
Replace the skewer with a $5 one from the bike shop, and ride the cannondale. You're not going to hurt it a bit putting it on the trainer, and the choice of gears will help you customize the workout (like spinning recoveries.)

Any bike that would be damaged by being on a trainer would be positively life-threatening on the road.

Where did we get this urban myth that trainers damage bikes? As many times as the question gets asked, no one has ever come up with so much as an "I know a guy who's uncle's cousin's mother's best friend's aunt heard about a guy who..." and yet the question keeps getting asked.

For once and for all, trainers stress a bike far less than riding over the most benign of road hazards at speed. It's simply not a problem. If riding a bike in a trainer would torque a frame that much, we couldn't possibly keep a bike upright and on the road without the rear axle connected to something solid.


FWIW, intervals indoors might not be your best training move. If you do intervals without a sufficient base, they're somewhere between useless and counterporductive. As it sounds like you're just now getting around to mounting up a trainer, it sounds like your base might be lacking. Maybe you want to consider using the trainer to get your base set, so you can hit quality intervals outside when the weather turns. Takes away some of the percieved threat to the bike, too. Of course, for base building, you could mount up the old bike if you wanted, too.
Skewer: Check. It came with the trainer.

As far as the bike, I don't think the trainer will hurt the bike (that's not what I meant to imply with the reference to how much it cost). I just see most people with old bikes mounted up to the trainer. Plus, tire wear is a concern. I don't want to swap tires alot when I switch from trainer to road (may be spur of the moment). So I guess I'll just have to try them both out and see.

Base wise, I think I'm okay. I'm just getting around to the trainer because our weather is nice here pretty much year round, and I haven't seen the need for one. That is until I decided to give intervals a try. The terrain is very hilly. I like climbing hills, but I'm looking for a little different routine. And, I can ride when I previously could not. I can do intervals while my 6 yr old is watching SpongeBob, y'know. By the way, I have about 800 miles on the R700 since October, and about 1250 total so far this year (since August). I'm not sure if that's a proper base, but it works for me.
 

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Tire wear is a thing, and swapping out isn't tough, but it's not a spur-of the moment thing, either. Maybe you put on some long-wearing training tires and have at it?

Most folks that have old bikes mounted up are probably that way simply because they have them available, and it avoids the switching altogether. In that way, the SS makes sense. The question becomes: will it offer enough variable resistance to make training properly effective? My trainer (which I never really use anymore, preferring rollers) is a mag unit with a remote (sorta like a shift cable) adjustment. If you've got something like that, you're probably in good shape. If not, you might want the 'dale for that reason.
 

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Discussion Starter #7
danl1 said:
Tire wear is a thing, and swapping out isn't tough, but it's not a spur-of the moment thing, either. Maybe you put on some long-wearing training tires and have at it?

Most folks that have old bikes mounted up are probably that way simply because they have them available, and it avoids the switching altogether. In that way, the SS makes sense. The question becomes: will it offer enough variable resistance to make training properly effective? My trainer (which I never really use anymore, preferring rollers) is a mag unit with a remote (sorta like a shift cable) adjustment. If you've got something like that, you're probably in good shape. If not, you might want the 'dale for that reason.
Yeah, it's a fluid trainer, no adjustments. I looked at those models (mag w/ adjustable resistance) and got the impression they were not as good as the fluid ones. So, having the gears on the C'dale is probably going to be the thing for interval training, and I'll use the SS for base/aerobic workout training.

Is there a good tire for all uses? The Armadillos are supposedly super tough, but they are pricey. I don't really relish having to replace (one of) them often.
 

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Downshift said:
Plus, tire wear is a concern. I don't want to swap tires alot when I switch from trainer to road (may be spur of the moment).
I just put an old tire on an old wheel and put a trainer skewer in it and swap wheels when I want to put the roadie on the trainer. This makes it very easy to swap in and out on the spur of the moment.
 

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I personally prefer the feel of my fixed gear on the trainer to my geared bike. It's a little more relaxed position, which may have somthing to do with it. It's also a much more flexy frame than my aluminum geared bike. I figure my trainer time is where I want to just zone out and spin, so the single speed is fine. I adjust the difficulty by tightness to the wheel before I start for how I'm feeling that day, then just stick with that for the ride.
 

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danl1 said:
For once and for all, trainers stress a bike far less than riding over the most benign of road hazards at speed. It's simply not a problem. If riding a bike in a trainer would torque a frame that much, we couldn't possibly keep a bike upright and on the road without the rear axle connected to something solid.
Actually, this isn't always true, which can be demonstrated with your own logic. A bicycle must be balanced to stay upright. If balanced forces weren't applied, the bicycle would fall over (or would at least veer wildly). Therefore, we can't apply large torques to the bike while riding on the road.

A trainer is different. The bike is laterally supported, so that large, unbalanced torques can be applied, and yet the bike will remain upright. That doesn't mean that a rider always does apply large unbalanced forces on a trainer - it just means that they could (whereas they couldn't on the road). A smooth, experienced cyclist may exert little torque on the frame on a trainer. But an inexperienced, undisciplined cyclists may exert large frame torques on a trainer - much more than they could exert on the road.

I witnesses a practical demonstration of this last spring. A rider showed up for a weekly ride who was very strong and athletic. In fact, she was a Spinning instructor, and spent hours and hours a week on a stationary bicycle. Unfortunately, she had a very unbalanced riding technique. In her technique, she tended to muscle and torque the handlebars. This resulted in random weaving (which made pace-lining with her disconcerning). Her veering was so wild that she even occasionally ran off the road. On a stationary bike, these unbalanced forces would have no affect at all, but on a road bike they could be disastrous. In fact, the following they were - she showed up again for the next, and in the middle of the ride she managed to crash herself by doing one of her wild weeves into the back wheel of the rider in front of her. Fortunately, she wasn't hurt, but on the rest of the ride, her random weaving continued, and she later she almost took down another rider.

What does this example demonstrate? That it is possible that riders can put much greater unbalanced stresses on their bikes on a trainer, because it does not need to be balanced to remain upright. While not all riders will overstress their frames, just that they can. The rider in this example was not only an experienced stationary cyclist, but in fact instructed others on riding stationary bicycles. And despite appearing to have great form on the trainer, she still applied highly unbalanced loads, which were only obvious when riding a bicycle without lateral support.

In response to your comment that "If riding a bike in a trainer would torque a frame that much, we couldn't possibly keep a bike upright and on the road without the rear axle connected to something solid.", the rider in this example actually was having great difficultly keeping her bicycle upright when the rear axle was not connected to something solid, whereas on a stationary bike she was free to apply to apply as much unbalanced loading as she wanted without fear of falling.

Oh yeah, one more comment - when applying lateral loads to a bicycle on the road, the torque loads are shared between both the front and rear dropouts, whereas on a trainer, all the loads are taken only by the rear dropouts. So on a trainer, not only is it possible to apply greater torque loads on the frame, but they are concentrated on just the rear dropouts.
 

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Mark McM said:
Actually, this isn't always true, which can be demonstrated with your own logic. A bicycle must be balanced to stay upright. If balanced forces weren't applied, the bicycle would fall over (or would at least veer wildly). Therefore, we can't apply large torques to the bike while riding on the road....
Good points, and a great example, but I disagree. Perhaps my example led away from my main assertion. Yes, it is possible to put unbalanced forces on a bike in a trainer, but they don't rise to the level of being dangerous to the bike, and they are less than the road commonly provides.

The most force we can apply to a bike on a trainer (short of purposeful abuse, which this would also constitute) would be to sit on the saddle and lean to one side until we tipped over. If any other use would exceed that amount, we'd be lifting the trainer feet with each stroke, which just doesn't happen. Now, I just went in and measured my trainer, and the feet sit six inches outboard of the dropout. It's also fourteen inches below. I'm not much in the mood for the trig at this moment, but that works out to a minority percentage of body weight of lateral force.

And as long as the skewer is fairly tight, the load will be shared by both dropouts, as they consitiute a system when locked together by the axle. Even in this extreme situation, most of the force differential will be absorbed as 'vertical' force on the chainstays, unless they are not connected by the axle. It's only the outboard ends of the skewer that are taking serious load, and we've bought a throwaway for that reason.

I don't argue that we can apply more loads by mistreating a bike on a trainer as compared to a smooth spin on a flat, level road. I do however maintain that we apply more force with routine, normal use in real-world road conditions than we do in normal, real-world conditions on a trainer. Sideways forces from the pedals (on the trainer) are minimal, due to lack of leverage. The crankarms sit inside the dropouts, so they simply can't apply meaningful lateral force or torque. All they can really do is shift the weight from one dropout to the other. And short of abuse, we maintain our weight fairly evenly over the top tube while on the trainer. So the 'excessive' torque simply isn't there. Meanwhile, look at a sprinter tossing a bike around on the road, the bike leaned one way, the opposite pedal weighted, the body centered over the BB. You just can't apply that kind of force on a trainer.

I'm guessing your girls' problem wasn't so much a choppy stroke as too much upper body movement. Nobody head-bobs on a trainer. It's a self-limiting thing - the trainer complains when you do, and so folks ease off. Ironic in a way - the very thing that makes folks think a trainer is damaging (those creaks, groans, and movement) is the very thing that prevents it from being. Keep in mind that she developed that technique on an 80-lb welded spin bike with a wide stance, not a 20-lb road bike gamely connected to a trainer.

My best argument, though, is probably anecdotal. We all know plenty of stories of bike damage in less-than-crash situations on the road. I've still not heard one report of damage from a trainer, other than "I tripped over it in the dark" stories. Even those were more about coffee tables than trainers.
 

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danl1 said:
The most force we can apply to a bike on a trainer (short of purposeful abuse, which this would also constitute) would be to sit on the saddle and lean to one side until we tipped over. If any other use would exceed that amount, we'd be lifting the trainer feet with each stroke, which just doesn't happen. Now, I just went in and measured my trainer, and the feet sit six inches outboard of the dropout. It's also fourteen inches below. I'm not much in the mood for the trig at this moment, but that works out to a minority percentage of body weight of lateral force.
The amount of lateral force is small, but because it can create a large torque on the drop outs. The drop outs are roughly 5 1/2" apart. If you applied a vertical load a further 6" away from the drop out, the torque generated will create a reaction force of about twice the load downward on the near dropout, and about equal to the load upward on the far dropout. We usually don't apply loads this far outboard when riding on the road, and even when we do, the reaction loads are shared between front and rear dropouts. In contrast, what happens when we hit a bump in the road? Normally about half our weight is on each wheel. If the bike is vertical and balanced, each dropout takes about half the load on the wheel, or roughly 1/4 of our body weight on each drop out. We would have to hit a bump with a g-force acceleration of 8-G to equal the force that can be applied to a single drop-out if we were to mount the frame on the bike and shift our body weight out about 9" to the side.

danl1 said:
And as long as the skewer is fairly tight, the load will be shared by both dropouts, as they consitiute a system when locked together by the axle. Even in this extreme situation, most of the force differential will be absorbed as 'vertical' force on the chainstays, unless they are not connected by the axle. It's only the outboard ends of the skewer that are taking serious load, and we've bought a throwaway for that reason.
The loads may be transmitted to the trainer through the skewer ends, but they have to get from the rider to the skewer somehow. And that load path is through the frame (and specifically, through the stays and droputs).

danl1 said:
I don't argue that we can apply more loads by mistreating a bike on a trainer as compared to a smooth spin on a flat, level road. I do however maintain that we apply more force with routine, normal use in real-world road conditions than we do in normal, real-world conditions on a trainer. Sideways forces from the pedals (on the trainer) are minimal, due to lack of leverage. The crankarms sit inside the dropouts, so they simply can't apply meaningful lateral force or torque.
If the point of load application were inside the dropouts, why don't our feet hit the chainstays? In fact, the point where loads are applied to the pedals are a fair distance outside the dropouts. Crank Q-factor (distance between pedal mounting faces) varies between 140mm and 150mm, so the ends of the cranks are already a little outside the dropouts. The distance between the crank the middle of the pedal body might be another 70-80mm. So pedal loads can be applied at a moment arm of 90mm or so outside of the dropouts. And again, the total torque might be low, but due to the narrow width of the axle, it can create large reaction forces at the dropouts.

danl1 said:
My best argument, though, is probably anecdotal. We all know plenty of stories of bike damage in less-than-crash situations on the road. I've still not heard one report of damage from a trainer, other than "I tripped over it in the dark" stories. Even those were more about coffee tables than trainers.
A quick search of usenet shows a few reports of frames being broken in trainers, like this one: Trainer frame damage thread. Where one to spend more than a minute of two searching, I'm sure there are more.

Many frame manufacturers also believe that trainers can damage frames, and explicitly exclude frames that have been used in trainers from their warranties. Here is one such manufacturer's warranty: Seven Cycles warranty
 

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Seven is one, not many. Most don't mention it at all, and a thread search right here will show where the specific question has been asked of manufacturers (trek among them) and they say it's no problem.

The thread you've listed mentions damage, though none explicitly blame the trainers unless I misread. Further, they mention damage at or near the BB, not the dropouts you seem so concerned about. That makes sense, as that is where the various torques of a bicycle and rider are centered. The forces at the dropouts are nearly all linear, for reasons of triangulation. Damage simply doesn't occur at the dropouts from a trainer. There, they are not capable of taking any more force than they are on the road. You don't believe that: I can't seem to convince you. We'll just let that drop.

Ignoring road forces for a moment, which as evidenced by snakebites can easily hit several G's (though by the way, you can't a bump with both wheels at the same time, so your estimates are off by at least half...)

Whether we pedal on the road or on the trainer, the torque comes from leg muscles. Since the bike stays upright and we don't corkscrew through space, there must be something counteracting that force in both instances. On the road, that opposing force comes from the inside of the thighs on the seat, or the arms against the handlebars. On the trainer, those forces are also in play, though because of laziness or bad form, some may be taken up by the trainer via the dropouts.

At first glance, we can see that the trainer distributes the stress to three points instead of two, which is clearly an advantage. Moreover, the dropouts are closer to the BB, so whatever force they are absorbing has a lower moment than that from the seat or bars. Net effect, the trainer exhibits more distributed and lower torque forces than a bike pedaled normally on the road.

There is a common misconception that a bike on the road has less forces on it because it can 'sway' to absorb some of the force, as in a sprint. I don't know how anyone who has ridden or watched someone else ride can come to that conclusion. For that to be true, the bike would have to sway 'with' the pedals, with the bike going right as the right pedal went down. But that's clearly impossible. The pedal going down indicates that the weight is over that pedal. If the bike was also leaned that way, the center of gravity would be to the right of the wheel's contact with the road, and we'd be nothing but a red stripe on the road.

What really happens as we pedal is exactly the opposite. As the right pedal is pressed, the bike is pressed left in order to maintain balance and increase the torque on the pedals. The BB is stressed more because the bike can sway, not less. To the extent that a poor-form rider moves himself rather than moving the bike under him when on the trainer, we still have the case that the righting forces are moving through a shorter moment (the dropouts rather than the seat/bars.) and so are limiting the torque.

Now, if the base of the trainer were very wide or bolted to the floor, and our rider made a habit of 'hiking out' for no apparent reason, it might be that meaningfully higher forces would be created on the trainer than on the road. But trainers aren't built wide or bolted to the floor, for this specific reason. The narrowness of the stance of a trainer limits the forces it can create to roughtly the same amount that a swaying rider can when on the road. That's how they limit their liability (practically as well as legally) for damage. Look at it this way. Imagine leaning over on a trainer until it begins to tip. Fix the angle between rider and bike in your head. That movement of CG away from the plane of the bike defines the torque on the bike. Now imagine a sprinter really tossing the bike around. Again, the CG deviation defines the torque. Now, move one of the images until the bikes are aligned. Pretty darned similar, aren't they? That's not an accident nor a coincidence. it's because an imaginary line drawn from a sprinter's CG through to the ground intersects at or near a point as far out as the trainer's legs extend. It's a part of the engineering analysis that goes into a trainer's design.
 
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