Using a seat post shim.

[allroy71]

I am thinking about getting a shim to use my gravity dropper in 31.6mm seat tube. Problem is that I have a 27.0 mm post and not a 27.2 mm.
There are no shims for 27.0mm.

What if I fabricated an aluminum can to bring the 27.0 to about 27.2mm? Do you think that would do?

[DeeZee]

Originally Posted by allroy71

I am thinking about getting a shim to use my gravity dropper in 31.6mm seat tube. Problem is that I have a 27.0 mm post and not a 27.2 mm.
There are no shims for 27.0mm.

What if I fabricated an aluminum can to bring the 27.0 to about 27.2mm? Do you think that would do?

However a 27.0 is smaller than a 27.2. The 27.2 to 31.6 may work just fine. If the shim doesn't fit you can widen it with a thin file or dremil (sp?).

Good luck!

[autoduel]

A coke can will do. Just place it between the shim and the frame to prevent movement.

[CalEpic]

Did you try calling Gravity Dropper for the correct shim?

They say on their website that they offer one.

C

[allroy71]

I did write GD. They told me that they only have shims for the 27.2mm.
My GD is a 27.0 mm. I looked at other bike sites and they only had shims for 27.2 and something in the 25s.

[Skeeter]

sounds like a good excuse to buy a new frame

[RacinJason]

Hmm your stuck.

[HUGH]

Originally Posted by allroy71

What if I fabricated an aluminum can to bring the 27.0 to about 27.2mm? Do you think that would do?

Why do I keep singing this song????

M I C (pause) K E Y (pause) MOUSE.... Mickey mouse... Mickey Mouse....

All jokes aside don't do the aluminum can thing. It WILL fail. Not in the parking lot but half way through your ride. Trust me on this one. I have seen it happen a few times.
If you Truly can't locate the shim you need PM me and we can work sompin out. I can make one.

HUGH

[jeffj]

Couldn't you just get a 31.8mm shim for a 27.2mm seatpost?

Jenson sells 'em.

Even if you had to file along one side of the slit, it should work fine. Nothing MM about that IMHO.

[OPP]

Originally Posted by jeffj

Couldn't you just get a 31.8mm shim for a 27.2mm seatpost?

Jenson sells 'em.

Even if you had to file along one side of the slit, it should work fine. Nothing MM about that IMHO.

Agreed.....I think will work just fine. I have (2) of these: one aluminum and one plastic. The Al seems to fit a lot tighter.

[autoduel]

You can get a 27.2 shim, but that doesn't change the fact that the post is .2mm undersized. That .2mm is enough to cause the post to slip even with the clamp tightened. It can also put unnecessary stress on the frame under the seat clamp. I don't see how a coke can shim is going to fail when it isn't in a position where there is movement. Burnish a lip on the top and it won't drop in the frame. BTW it only takes one layer for .2mm. I definitely wouldn't use a coke can for more than a 1 layer shim.

[RacinJason]

Hey Jay you should do it right. Get a custom shim made. GD told me that they would send me one for my gd to fit a 31.6 . I wont ride with a shim on my post not that it wont work I will just know its there . Kinda like I wont ride patched tubes. I will change them out . To me it is just somthing waiting to go wrong.
I went back to my thompson. I have a prototype Rase post that I am helping them develop but it is still inder construction. It will have many more positions of adjustment that the gd . Come over and check it out.
What bike are you thinking about getting. I think you need to ride a Chumba that is set up correctly for you. Maybe one of our 08 EVO's Check out the mtbr reviews or even the xcl can handle everything you will be doing.

[jeffj]

Originally Posted by autoduel

You can get a 27.2 shim, but that doesn't change the fact that the post is .2mm undersized. That .2mm is enough to cause the post to slip even with the clamp tightened. It can also put unnecessary stress on the frame under the seat clamp. I don't see how a coke can shim is going to fail when it isn't in a position where there is movement. Burnish a lip on the top and it won't drop in the frame. BTW it only takes one layer for .2mm. I definitely wouldn't use a coke can for more than a 1 layer shim.

It would not be undersized, he would only need to squeeze the shim a little bit more to get it into the seat tube. He may need to file along the gap if the two sides meet when the shim is inserted into the seat tube, but other than that, the thicknesses of the post and shim would match up perfectly.