Background: I used to ride a set of American Classic sprint 350 never had any problems until I dented the front rim riding over a cuddle grate
I replaced the front wheel with a m5 straight pull hub laced the a 20h stans alpha 340 rim and now on some descents my rim hits the brake pads
So do these parts have history of being flexy?
Is there any fix?
PS: less than 60kg rider
Flexy wheels?
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The rim is a low profile rim @ 380g so it's gonna be flexy even with more than 20 spokes.
Stiffness is a function of bracing angle (wider is stiffer), spoke number and weight (heavier are stiffer) and rim weight (heavier -> stiffer). At the same weight, a wider rim will flex more than a taller one very generally.
The simplest option would be to get a front wheel with a heavier rim or more spokes.
Stiffness is a function of bracing angle (wider is stiffer), spoke number and weight (heavier are stiffer) and rim weight (heavier -> stiffer). At the same weight, a wider rim will flex more than a taller one very generally.
The simplest option would be to get a front wheel with a heavier rim or more spokes.
Try a deeper section rim. The rim is a tube, and the stiffness of a tube is mostly determined by its diameter.
Unfortunately the deeper section rim will also be heavier.
Another solution would be to run your brakes with more clearance. Many riders set their brakes too tight. All you need is for the lever to not bottom out on the bars when you squeeze hard. On may brake caliper designs the leverage ratio is not linear- the leverage is less (pads move more for X amount of lever travel) in the initial travel, to take up
the clearance. In the middle range the leverage ratio is increased to make the brakes more powerful. Setting the clearance too tight means that the pads contact the rim before the caliper gets to the more powerful ratio, so you have to squeeze harder for a given amount of braking.
Unfortunately the deeper section rim will also be heavier.
Another solution would be to run your brakes with more clearance. Many riders set their brakes too tight. All you need is for the lever to not bottom out on the bars when you squeeze hard. On may brake caliper designs the leverage ratio is not linear- the leverage is less (pads move more for X amount of lever travel) in the initial travel, to take up
the clearance. In the middle range the leverage ratio is increased to make the brakes more powerful. Setting the clearance too tight means that the pads contact the rim before the caliper gets to the more powerful ratio, so you have to squeeze harder for a given amount of braking.
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Theh 340 is an inherently soft rim especially if you have the 1st rendition of that hoop. I'd say that erics suggestion of opening up your brakes a bit is the best one. If you don't want to do that they you will need to switch to a stiffer (ie heavier) rim.