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Ok, so ive got my old 2000 and a half Kona Stab Dee-Lux and im constantly breaking the lower shock mount bolt (by the bb) and despite upgrading toa higher grade bolt its still breaking. Ive heard of some people drilling out the the mount and shock bushings so that you can put a larger bolt in there. What i wanna know is will this really work, cause im desprate, this is happening every month and a half or so and i dont have the money for a new frame. Any thoughts (or frames )would be greatly appreciated, thanks 's

-Mt.Dew

 

[ChrisKring]

What do you define as a higher grade bolt? Most people tend to think that a Stainless Steel bolt is stronger than a steel bolt. However, it is much weaker.

Also, are you using a torque wrench to torque the bolt? It will make a big difference on the cyclic fatigue of the bolt if it is torqued to properly. Without a way to guage the torque, most people undr torque the bolts to avoid stripping out the linkage.

Are the bolts failing immeaditly on the first big hit or after a bit of riding they just fail on something small? If it's the latter, the bolt is failing due to fatigue.

 

[Rik]

I'd be wary of drilling out the shock. Look at it this way: You can have a 10c bolt break on you occasionally, or you could reinforce the bolt, and have other, more expensive parts break.

 

[sub6]

sounds like you might be bottoming really hard. Shock bolts shouldn't break like that - my understanding is that frame is very linear and I'd expect it to bottom hard.

What is the stroke length of your shock, and what's the stroke of your spring? The spring should have a longer stroke than the damper, otherwise it'll coil-bind and bottom really hard - this would definitely break your bolts.

Also, you might want to investigate getting a heavier weight spring, if you're bottoming a lot. If you're running more than a couple turns of preload, you're probably a) running too soft a spring, and b) causing the spring to coil-bind. If you have, say, a Fox RC 2.25" stroke with a 2.3" spring, you can preload the spring like 2 turns, that takes up the .05" of "extra" stroke you've got. Any more, you'll coil-bind at bottom-out.



As for bolt grades, get a 12.9 bolt, non-stainless.

Shock bolts, iirc, come usually in 6mm or 8mm. You could drill out your bushings to 8mm to take that size bolt; you'd also have to drill the mount holes in your frame, which may or may not be a very good idea depending on how much material would be left.

 

[Echo]

As usual, sub6 has probably figured it out... get a stiffer spring.

 

[PoweredByMt.Dew]

Well, its breaking after several big hits, such as the other night when i rode skatebarn, i replaced the bolt a ride or two before that. all the i know about the shock is that its a Fox vanilla RC and the spring says either 550X229 or 350X229 on the spring (cant tell, part of its been rubbed off). I would more than likely get a new sping save for the fact that ive literaly got zero cash. Im just going to tolerate breaking a bolt every now and again till i can get a job i guess. thanks guys

 

[VTinCT]

Take up road riding!

 

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I already do!