Bending Colubus Zona.

[AFarr]

Hi all, first time posting here! I'm build a 650b mtb with Zona. I'm using a 31.8 DT, 650mm Kxdt-757-650 it says on the invoice. I wish to have a slight bend in the HT in, to clear the fork crown and aesthetics. I was going to trust the job to a local tube bending specialist, rather than risk it myself. I gave them a call and he asked 'how many of these tubes do you have, in case it go's wrong. Well the answer is none, and I live in New Zealand, so would have to wait a while and pay a small fortune in shipping to get another one. After a search online i've seen that some builders won't even attempt a bend with OX Platinum and use 4130 etc instead. I wouldn't be adverse to this and using the 4130 as a sleeve for the 31.8, if I could actually get any 4130 in NZ, which I have yet to find a supplier of.

So my question is..... does anyone have any experience of this? Is Zona to thin to bend well? The bend will be 15 degrees, and I presume done by people that have a lot of experience in bending pipes, just not Zona bike tubes.

Many thanks for your input.

[Undies]

Not sure you want to bend the HT assume typo and mean DT
I am in Wellington and will have a new 3 roller tube bender next month(ex US) but don't have the dies for this diameter tube
Critical is to roll the tube slowly and make sure the dies are the correct diameter for the tube
By vertue of the process the tube will thin on the outside of the radius but the Zona seat tubes I bend to a similar radius work well.
If theystuff one of your tubes I have a replacement tube but you would need to replace it

[edelbikes]

Do you know which kind of bender they would use for the job ?
They could at least fill the tube with cerrobend or bendalloy or similar to help...

[steve garro]

I would not have high hopes.
- Garro.

[afwalker]

Undies: Is your 3 roller bender like the Harbor Freight? This guy makes nice dies with many sizes in round.
Harbor Freight Tubing Roller Dies
But I would only try non-heat treated stuff like Versus. Even still, I fill with sand.
Couple shots on my flickr page.
cheers
andy walker
Flickr: afwalker's Photostream

[steve garro]

I can roll 1.125" x .028" into a 24" diameter circle - no ripples, no kinks, no sand.You could go smaller, but you would have to cut it off the bender.......
- Garro.

[Curious George]

... I live in New Zealand, so would have to wait a while and pay a small fortune in shipping to get another one....

I cant help with the bending question sorry, but if you are in Auckland, try these:
Cardwell : Only have roll cage stuff in 6' lengths, but you never know
Aviation and Performance : Worst web page ever, but give them a ring, they had quite a bit in stock last I was there, and can get anything from this enormous aircraft spruce catalogue.
I found it as cheap to get some proper bike stuff from Ceeway, I didn't save anything by getting 4130 just so you know.
If you want cheap tubing (for practice) get some ews tube - Steel North Shore
Where in NZ are you?

[suspectdevice]

I can roll 1.125" x .028" into a 24" diameter circle - no ripples, no kinks, no sand.You could go smaller, but you would have to cut it off the bender.......
- Garro.

I'm 100% sure it'll crimple(tm).
Bending butted tubes requires a super duper long thick section. Remember, to bend the tube you need lots of extra tube sticking out the end of the bender and it needs to be thick, otherwise it'll crumple.

[steve garro]

Remember, to bend the tube you need lots of extra tube sticking out the end of the bender and it needs to be thick, otherwise it'll crumple.

Yep - 6-8" on my roller.
- Garro.

[bellman]

butted tubes don't bend or roll (at least in my shop)

I have however rolled the lower part of a seat tube in oversize dies to create tire clearance by adding a slight bend and ovalizing at the same time.

[afwalker]

Maybe the Non-Heat Treated ones do: eg Versus 1.125"
bending versus 1.125" | Flickr - Photo Sharing!

Here's those Swag dies for 1.125"
swag dies on HF bender | Flickr - Photo Sharing!

cheers
andy walker

[steve garro]

Maybe the Non-Heat Treated ones do: eg Versus 1.125"
bending versus 1.125" | Flickr - Photo Sharing!


cheers
andy walker

That's the 1st tube I chucked up in my roller.
it would do fine, except that where the internal butt is it makes a big crease-bulge.
Next.
I just did a giant frame with 1.125" x .035" and it sleeves a 30.0mm seat post beautifully, that's likely what I would use for a small seat tube/tight clearance/curved seat tube 29er - Garro.