27.4 post shim options

[ishaw]

I had a plan for a build, but might change it. Challenge is that the frame has a 27.4 post. I have a black Thompson, but thinking of red bling. I can get a red use post in 26.8 or 27.2, but not keen on the beer can shim as it's a nice frame I don't want to break.

I've searched online and haven't come across a shim that would do the job, anyone know if such shims exist?

 

[d8mok]

If this is for the Lightning …. It’s not as easy as all 27.4 posts fitting

I bought 3 nice posts for mine and only 1 fitted. 27.4 Thomson was too big but 27.2 too small.

 

[mk one]

Have you considered a normal USE post with a 27.4 shim?

 

[ishaw]

If this is for the Lightning …. It’s not as easy as all 27.4 posts fitting

I bought 3 nice posts for mine and only 1 fitted. 27.4 Thomson was too big but 27.2 too small.

Yup. The Thompson I have does fit iirc. Been a while.

 

[ishaw]

Have you considered a normal USE post with a 27.4 shim?

Kind of, but not able to lay my hands on one as easily in red, or silver with red bits.

 

[dan28]

you cant shim from 26.8 to 27.2
think about its 0.4mm so 0.2 tube thickness either side
may you could clean the existing post remove the andoising an polish it

 

[ishaw]

you cant shim from 26.8 to 27.2
think about its 0.4mm so 0.2 tube thickness either side
may you could clean the existing post remove the andoising an polish it

I've had that thought. Even if it would work, I'd doubt I could bring myself to potentially ruin a perfectly good post.

Might have to go with what I have, maybe a black x-lite stem rather than silver to tie in the black Thompson. Maybe some red bolts will do the job?

 

[Nabeaquam]

Aluminum flashing, JB Weld it in place holding it with the undersized post, grind the seat tube slot wider, use grade 8 bolt, weld a tab onto the bolt so it won’t turn when tightening, toss the hot welded grade 8 bolt in water and clamp with all your might with a socket and ratchet. If that doesn’t get it cut a slot on the front side of the seat tube. Inelegant but they make hammers, grinders and glue for a reason. Worked for me.

 

[89RingleAddict]

Maybe this will help
Maybe I will get chastised
BITD…..1990’s
If you wanted ‘bling’….you bought part from magazine add
Then ‘made’ it fit
That’s what I did more than 20yrs ago
I have never had issues….never raced, but medium to hard riding when I was younger

I had same fitment issue with my SP
I made a shim
Couple ways u can go here
Here is pic of what was final product was (and is) presently

 

[89RingleAddict]

The first option
Get similar size material for shim

I used portion of the SP that fit
Then honed out the inner portion at friend’s shop
Vise is critical, I used a hand held drill
The drill bit was cylinder shaped (like a can)
Then cut a vertical slit
i remember this took me hours to get perfect