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Old 09-15-2010, 07:07 PM
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Al.Fisherman Al.Fisherman is offline
Motorized Bicycle Elite Member
Join Date: Sep 2009
Location: Calera, Alabama
Posts: 1,966
Default Re: Snapped Rear Mounting Studs (3rd time!)

Most common reasons for studs to break are..

Cheap Chinese studs... I change out ALL to grade 8.8 About the same as US grade 5.
Incorrect mounting...mounts to both seat tube and down tube. Need as close to perfect fit.
I use RED locktite on all studs (if removal is desired heat is needed).
Proper torque 6mm 50-70 INCH pounds... 8mm 150-204 INCH pounds (I use 50 and 150)
I double nut with a nylock nut as the second one.
Here are some pictures of my mountings, I have never had a nut or stud, come loose, break or strip out.

Proper mounting...

I make these shims in order to get the proper torque. The nuts are too close to the clamp for a proper socket fit. I don't have a nylock nut on this illustration.

I make this "L" bracket to eliminate engine twist due to engine torque. This way I don't have to over tighten mount nuts.

Almost every bike frame needs a custom made front mount. The proper angle for the optimum mounting is 75 degrees.
..........A bought mount can be had
Looking for HT's parts?
HT pre instillation tips.
Engine running problems?
HT breakdown Photos

Ron ><)))))*> Calera, Alabama

Last edited by Al.Fisherman; 09-15-2010 at 07:21 PM.
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