Seat tube sleeve

[padelsbach]

Hi all,

I'm a bit of a framebuilding and VS newbie, so apologies in advance for this question ...

I'd like to use this tube/sleeve combo from Nova for a brazed frame. But I'm not sure how to adhere the alloy sleeve to the tube. Any ideas?

Thanks.

[Erik B]

Hi all,

I'm a bit of a framebuilding and VS newbie, so apologies in advance for this question ...

I'd like to use this tube/sleeve combo from Nova for a brazed frame. But I'm not sure how to adhere the alloy sleeve to the tube. Any ideas?

Thanks.

I have used a combination of gravity and friction to hold seat post shims in.
Builders have also been know to use epoxy to secure shims.

IMHO the best solution is to use a properly sized seatpost.

[Eric Estlund]

Odds are good that after welding or brazing you'll have enough distortion to hold it in with a press fit (especially if this is an early frame). A little bit of epoxy goes a long way with this sort of shim.

[padelsbach]

Thanks guys for the quick responses.

[Andrew R Stewart]

The sleeve once pressed in might need a skuffing ream, espically if there's significant distortion to the seat tube from brazing/welding. Andy.

[steve garro]

You're going to get some major distortion brazing right to .6mm
I use a 1.25" x .035" for bikes that will see hard use or tall riders.
= 30.0 seatpost with a slip fit sleeve if you want to run a 27.2
Clean.
- Garro.

[padelsbach]

= 30.0 seatpost with a slip fit sleeve if you want to run a 27.2

hey Garro, thanks for the reply. Can you clarify what you mean by this?

[Chauncey Matthews]

hey Garro, thanks for the reply. Can you clarify what you mean by this?

He means using a 1.25x .035 seat tube will be better for brazing and give you the option of running a 30.0 post or you can sleeve it down to a 27.2 if'n yantoo.

[jon_norstog]

You're going to get some major distortion brazing right to .6mm
I use a 1.25" x .035" for bikes that will see hard use or tall riders.
= 30.0 seatpost with a slip fit sleeve if you want to run a 27.2
Clean.
- Garro.

yeah,

Most of my bikes use that same seat tube. I go for a 29.8mm Thomson 'post. It's da bomb. Shims? I've heard of them.

jn


"Thursday"

[steve garro]

yeah,

Most of my bikes use that same seat tube. I go for a 29.8mm Thomson 'post. It's da bomb. Shims? I've heard of them.

jn


"Thursday"

Great minds think alike!
Hope you got your elk this year, Hastiin.
- Garro.

[jon_norstog]

Great minds think alike!
Hope you got your elk this year, Hastiin.
- Garro.

No animals were harmed in this year's hunt. I sold the "Elk Hunter" prototype bike after the Portland show and plan to build another but with clearance for 3" flotation tires. proof of concept!

Degenerate minds think alike, too!


"Thursday"

[afwalker]

Can I ask which tubing is being talked about here?
Straight 4130 1.25 0.035 has ID of 1.18"/30mm so the Nova sleeve won't fit?
Thanks, I'm just confused:)
andy walker

[Eric Estlund]

The first poster inquired about the 31.8 8/6 Nova tube and shim. Steve countered with a 1.25/ .035 (31.8/ .89) suggestion in lieu of a shim.

[steve garro]

The first poster inquired about the 31.8 8/6 Nova tube and shim. Steve countered with a 1.25/ .035 (31.8/ .89) suggestion in lieu of a shim.

.............But, with an external sleeve for good measure.......................!
- Garro.

[fortyfour]

Personally I use a 1.25" OD x .035" Wall thickness steel tube for most of my mountain seat tubes. I source my seat post shims from Cane Creek (OE Cost is very affordable) who offers them anodized in black and slotted in a variety of sizes/dimensions. I typically size them down to accept a 27.2mm post. However, I do not epoxy it in place. This is one area on a steel frame (IMO) that warrants the foresight of removal. New England is wet. I like the ability to remove, clean and re-grease the shim inside and out every season on all my personal bikes. I also recommend this to clients. If anything ever gets seized, broken or marred, it's good to have a part that can be removed, replaced, repaired, or in most cases, maintained. Not to mention you can ream and hone the inside of the tube to an acceptable tolerance but the interface between post and shim is very precise.

[jon_norstog]

I guess I'm a little OT, since the OP seems to want to use a "standard" seatpost in and OS seat tube. But here goes:

One reason I went to the 1.25" seat tube is I was bending 27.2mm seatposts - I weighed 200 at the time and while I ride hard I wasn't taking a lot of drops, well, not big ones anyway. The only 27.2 'post I rode that felt secure was the Thomson. I went to the bigger ST so I could run cheap seatposts without worrying about having to have them surgically removed.

The additional benefit the big ST provides is stiffness in the heart of the frame. So for mountain bikes and stuff that gets ridden sitting down I use a .9-.6mm butted tube and a 30.2 or 30.4mm 'post. For BMX bikes, Slalom/4X and extreme riding/riders, I use 1.25" x .035" aircraft tubing and the 29.8mm Thomson.

For light riders and most roadies, the 27.2mm 'post works just fine, and I put that size on the (few) road bikes I build. And I do use that size for children's BMX bikes - mini/junior/Xpert.

[afwalker]

This was a great question, I'm sure learning a lot.
Thanks
andy walker