Weight Weenies

No way is the steerer tube flexing. Fork blades maybe. Not steerer tube.

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Steerers can be flexy. I had a light carbon steerer on my Lefty that flexed so much that it felt like the headset was constantly loose. I switched it for a different one (also carbon) and the problem was immediately resolved.

@Privateer: out of curiousity, what carbon steerer did you find flexy and what did you replace it with (and find stiffer)?

The fork is stock on my Museeuw MC-2 (http://en.museeuw.com/bikes/race/mc-2). I'm not saying the "test" I did was scientific in any way. I can't imagine what kind of situation I would find myself in where the front wheel is trapped in place and I needed to twist the bars. I've also noticed bar movement when I get out of the saddle on the trainer, so something is flexing. The fork legs may be the more likely culprit. In any event, I can only report that when I perform the same "tests" on my MC-2 and my Team Carbon, there is less movement with the latter.

Given that the diameter of the legs is much larger than the steerer, I don't see why some people think it must be the fork legs. I once swapped a cheap Trek carbon fork with an alloy steerer for a Look full carbon fork and there was a massive difference in stiffness that I think was definitely attributable to the steerer tube change. Not that this helps you do anything about it of course, other than removing spacers and /or changing the fork.

Whether its the fork blades or the steerer, what does it matter? The fork itself is still flexy. It could be the headtube too, but the bottom line is that the frame or fork has to be swapped.

Seriously. I thought I was talking to a bunch of weight weenies. Nope, I must've missed the renaming of this website to stiff weenies.

In the Olde Days race mechanics would drive a broomstick down the steerer tubes of bikes to be ridden in Paris-Roubaix to reduce steerer breakage.

You could expoxy an appropriate sized carbon or aluminium tube in there, as was suggested above.

All interesting ideas, but none seem (a) worthwhile or (b) appropriately WW. I think I'll live with it and take this as a license to ditch my bulky compression plug in favor of something lightweight.

dwaharvey wrote:@Privateer: out of curiousity, what carbon steerer did you find flexy and what did you replace it with (and find stiffer)?

It was a Hellore. I replaced it with a Black Cat Bone.

Just tested this on my 2018 Diverge Elite and 2020 Crux and other 2020 Diverges at LBS - they all flex, and it's the fork blades - such is the design

dwaharvey wrote: ↑

Fri Mar 22, 2013 5:33 pm

Given that the diameter of the legs is much larger than the steerer, I don't see why some people think it must be the fork legs. I once swapped a cheap Trek carbon fork with an alloy steerer for a Look full carbon fork and there was a massive difference in stiffness that I think was definitely attributable to the steerer tube change. Not that this helps you do anything about it of course, other than removing spacers and /or changing the fork.

Two facts:

1, shape. Blade shape is less stiff than round laterally.

2, tube thickness. Steerer tube is usually much thicker than a rim brake fork.

Basic loading on the steerer is mostly twisting in the example given. Tubes are buggers to twist.
The fork legs are bending. Much easier to do that.

https://www.intend-bc.com/products/headset/stiffmaster/
Problem solved.

If it really is the steerer tube flexing, then this might be helpful: https://www.intend-bc.com/products/headset/stiffmaster/

Cheers, Lars

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