I’ve noticed with my set of Mavic Ksyrium Sl’s that I get a lot of flex when I’m pressing down hard, or up out of the saddle on a climb.
Does this mean I need a stiffer wheel or more spokes?
Is that the right way of thinking?
how do you notice this flex, exactly?
Those are pretty stout wheels, perhaps whatever you are noticing is normal, or perhaps it is the frame, or crank that is flexing?
The best way I can describe is that there is a bit of give. Not like something is going to break.
I’ve noticed when I had the wheels on my Cervelo RS and my Cannondale Caad10. I counted the spokes and I see 18 on the front and 20 on the back.
Being a bigger guy around 200 pounds, maybe its the spoke count? I’m imagining? Its mostly when I’m up out of the saddle and rocking my bike.
I had the mavic equipe with the same spoke count and they didn’t flex under me @260 pounds. You sure its coming at the wheels?
I can’t say for certain. I just assumed it was them. I’ve been on open pros with a higher count and didn’t have the same sensation.
I’ve noticed with my set of Mavic Ksyrium Sl’s that I get a lot of flex when I’m pressing down hard, or up out of the saddle on a climb.
I’m guessing you mean that something feels “soft” in your drivetrain… like sort of mushy when you press hard in a small gear on a steep climb?
Your wheels have poor torque stiffness because there are only 10 low modulus (aluminum) spokes, and a small flange diameter. It is bad enough that you can make the “pushing” spokes go slack on steep climbs + hard efforts… which will cause the wheel to go limp (relatively). This should only happen when you are in a small gear though. If it happens in a larger gear on the flat also, then something else is going on.
Thanks for explaining that. Happens in a smaller gear climbing out of the saddle. Solution, get a wheel with more spokes?
I got a set on Easton EA90 SL. Had a bit more spokes, but maybe will experience the same.
Do not feel it on the flats as you said.
Thanks.
The solution has to do more with getting wheels that have a different material for spokes. Most wheels are steel spokes for a reason. The Al spokes are a softer spring and that is what you are feeling.
Solution, get a wheel with more spokes?
I’m surprised more people don’t complain about this with the Ks. They are the most likely to suffer from it since they have crossed spokes on the NDS only (which have low tension to start with), only 10 of them, and a small effective flange diameter.
The Eastons might experience this also, but it will take more torque before it’s a problem. Large flanges, high tension, crossed spokes on DS, and more spokes will all improve things. You probably don’t need to get extreme if the wheel is built well.
I doubt it is the spoke material. Aluminum is more elastic, but they make them fatter to compensate.
Hi rruff,
Prezactly. I’ve run Zicral spokes in a tensile test versus butted stainless, and the increased cross section cancels the decreased modulus almost exactly.
Cheers,
Finally took the wheels out for a first ride. One question I had was some popping sound. I got up out of the saddle and heard some popping, almost like the spokes were being stretched or pulled into place. I don’t know how else to explain it. It happened a few more times and then didn’t really hear it again.
Feels a lot stiffer than my Ksyrium SL’s, but I think still have a tad soft feel occassionally.
New wheels? That usually happens if the spokes were built with some residual twist, and they pop as they unwind. But other things could “pop” also. If it goes away after awhile it was probably twist, but that also means you will need to retension and true them.
Thanks for the tip. Will run on my stand and see after each ride.
Finally took the wheels out for a first ride. One question I had was some popping sound. I got up out of the saddle and heard some popping, almost like the spokes were being stretched or pulled into place. I don’t know how else to explain it. It happened a few more times and then didn’t really hear it again.
Feels a lot stiffer than my Ksyrium SL’s, but I think still have a tad soft feel occassionally.
What cog are you in when you hear it? Any chance it’s the rear derailleur?
I don’t recall which but was probably middle to higher gear. I’ll have to try to figure it out next time I’m out.