PROBLEM SOLVED with seat clamp!!

[spinman]

Well, the only part I had to drill out was the outer rail clamp as shown in the pic. The other parts already fit a 3/8". Hmmm, could it be cuase the makers already know this problem will occur down the road and made it easier for us?

Anyhoo, I cut a length of 3/8 thread rod and when all put together it tightens up like a dream. I'm gonna do the same with my other seat clamp. The beefier the better. :mrgreen:

Spin

 

[deorman]

Re: Why do i get play in a tightened seat clamp??

Either you're running out of threads before the post clamp is fully tight, or the rail clamps are distorted and bottom out before clamping the rails. I've returned from rides standing all the way from this happening to reused overtightened clamps before. :roll: You can add some washers to the outside to cure the first cause, but replacement is the only cure that will last for the second.

 

[spinman]

Re: Why do i get play in a tightened seat clamp??

Thanks for the feedback. I think it's what you say about running out of thread. I'll go grab some new nuts and some extra washers.
I guess that's why my LBS guy said you have to tighten each side down evenly.
Spin

 

[Bendix]

Re: Why do i get play in a tightened seat clamp??

liberally greasing the threads can make a big difference when tightening cheap hardware.

 

[B607]

Re: Why do i get play in a tightened seat clamp??

I had that same problem and broke that square looking bolt. Twisted the threads right off. I replaced it with a bigger one. I think that square bolt is 1/4" IIRC, I put a 3/8" bolt on mine and cranked it down hard. I got on the seat and started bouncing up and down to test it. The clamp held the seat okay but I bent my factory Schwinn tubing seatpost! Mission accomplished! Gary

 

[spinman]

Re: Why do i get play in a tightened seat clamp??

"...I put a 3/8" bolt on mine and ....."

I was thinking of drilling out the pieces to 3/8" and uding s leength of 3/8 threaded rod. Only problem it wouldn't have the square area in the middle. i wonder if you really need that square part? I guess it serves some purpose.

Spin

 

[deorman]

Re: Why do i get play in a tightened seat clamp??

The post clamp often has a shaped hole (square, or with notches in the side), it keeps the bolt from rotating. :wink:

 

[spinman]

Re: Why do i get play in a tightened seat clamp??

I'm gonna drill it out to 3/8"s and see what happens. :?

 

[B607]

I used a carriage bolt...round head with a bit of square just under the head. I think the square keeps the bolt from rotating when you crank it down. Gary

 

[deorman]

Some older seats actually start with a carriage bolt, with a square hole on the outer clamp or the saddle undercarriage.