can a carbon frame take this?

The term is "flexing". Every bike has a certain amount of flex, even carbon. There is less flex and it is normally not noticed when one is riding or training on rollers because the bike is free to move. It is more pronounced on a trainer because the rear wheel is held captive. I don't know how much flex was shown on your video, but you can flex carbon a fair bit over the length of the tubing on a normal road bike. A small amount of flex won't hurt the frame, but a lot of heavy flexing will probably shorten the life of the frame.

Although other factors such as the type and quality of the joints can complicate things, carbon is better able to handle fatigue than many metals.

I have been riding my bikes (steel and alu/CF) on trainers for years and while they flex like crazy, nothing serious appears to have happened to them.

Train away, my friend.

Funnily enough my Cervelo Soloist flexes way more than my old alu Specialized Allez on the trainer. For that reason I prefer not to use the carbon bike in the trainer

Powerful Pete said:

I have been riding my bikes (steel and alu/CF) on trainers for years and while they flex like crazy, nothing serious appears to have happened to them.

Train away, my friend.

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At the end of the day, these flexes will induce fatigue in all materials. If you aren't game to do it on a CF frame, then you really shouldn't be doing it on a steel or alu frame either. I'd think that a competent bike R&D manufacturer would already have done the necessary mechanical tests like this.

Hmmm....It's a good point though...

Someone should be out there now designing a new trainer that has flexible supports with heavy-duty springs or something which allows the rear wheel/axle to sway with the rider. This will take the unrealistic stress off the chain and seat stays, and also give a feel that is more realistic. Patent pending...

Crankyfeet said:

Hmmm....It's a good point though...

Someone should be out there now designing a new trainer that has flexible supports with heavy-duty springs or something which allows the rear wheel/axle to sway with the rider. This will take the unrealistic stress off the chain and seat stays, and also give a feel that is more realistic. Patent pending...

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Its already been done. They call it "Rollers". Why do I gotta be the f**king dictionary on this post?

C'mon... Get your style right. No rocking the bike, keep your upper body relaxed, keep your spin smooth and efficient. I repeat, NO ROCKING!

sogood said:

C'mon... Get your style right. No rocking the bike, keep your upper body relaxed, keep your spin smooth and efficient. I repeat, NO ROCKING!

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Have you seen a sprint finish at the end of a Pro race from the front? Tom Boonen for instance?

kdelong said:

Its already been done. They call it "Rollers". Why do I gotta be the f**king dictionary on this post?

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Funny one dude.

Except that, whilst its fun to balance on rollers, rollers DO NOT mimick real riding physics. Wiith forward momentum a bike has inertia that makes it easier to balance. Consequently, that's why its easier to ride in a balanced straight line when going 20 mph as opposed to 1 mph. The spinning wheels do give some gyroscopic inertia though, the same phenomena that keeps a frisbee stable.

So a trainer that gives some righting force but still allows sway, may mimick real riding better than rollers possibly, and certainly would be easier to ride than rollers for the majority of cyclists. But its only going to be different when your off the saddle.... and its just an idea.

Cycler6n said:

they already got those, kurt kinetic makes em, called the rock and roll, it sways left to right w/ the bike

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This is the thing I love about this forum... You learn so much so quickly.

Thanks Cycler6n...you saved me a whole Christmas of dreaming and loads of embarassment when I ultimately took the idea to the market.

sogood said:

At the end of the day, these flexes will induce fatigue in all materials. If you aren't game to do it on a CF frame, then you really shouldn't be doing it on a steel or alu frame either.

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For steel and ti if the flex is below the fatigue limit then there will be no damage. Not sure about carbon though. Ask alienator.

What training I have done on trainers, I have noticed a little flex in the threaded bolts on the trainer, not so much as on the bike itself. If so, that will relieve a little stress on the frame.

Crankyfeet said:

Have you seen a sprint finish at the end of a Pro race from the front? Tom Boonen for instance?

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sure. and do you seriously think he practices that action on a trainer?

trainers are really good for lots of things, but getting your full throttle sprint down simply isn't one of them.

--brett

Crankyfeet said:

Have you seen a sprint finish at the end of a Pro race from the front? Tom Boonen for instance?

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You don't seriously practice sprinting on a trainer, or even climbing for that matter. For real practice, you need to get outdoors.