TL;DR – Can I (is it sensible to) ream out a 2007 Giant trance seat tube to take a 31.6 post? I think its 34.9 clamp size.

Was thinking about Gravity enduros next year and how Coed-y-Brenin was so pedally, then thought about how I have a 2007 Giant Trance frame in the shed doing nowt. Could be a good idea to race that for that round rather than my heavier sofa like 160mm Last Herb. 140mm Marz 44 rc3 ti forks/125mm rear travel would be just the ticket. My reverb is 31.6 dia though and the trance is 30.9. But. As the clamp on both bikes is 34.9 would it be possible to ream out the seat tube to take the reverb?

If this is all a bad idea I might sell the frame instead.

have they actually announced where the rounds are going to be next year yet? Given the amount of people who moaned about the CyB round I wouldnt be surprised if its dropped for next year. I get the impression from the FB site that its going to be more DH focussed next year (which is a shame if you ask me)

Or get another seatpost?

18 bikes have been doing reaming on some bikes to take dropper posts.

Might be easier just to get the right sized reverb though?

Oh and you can’t get 44 RC3’s new anymore 🙁

To reply to the replies so far:
I’ve heard coed-y-brenin is still in the shortlist due to its all weather riding. Definitely not counting it out right now.

I’d be swapping the reverb over from my full sus hence the modifying of seat tube. Not buying another dropper post for possibly one race. *mind you i don’t know how much reaming is.

Yeah I saw a twitter post about 18bikes reaming out a seatpost which is where that idea came from. Seems as though there is enough spare material with a 34.9/30.9 combo.
And I’ve got some 140mm 44 rc3 ti on my cotic soul at the moment so swapping those over would be no trouble at all.

Has anyone done what dirtbiker is suggesting? I’m tempted by the idea (30.0mm seat tube up to 30.9mm), though concerned it could take too much strength out the seat tube? Be good to hear of any experiences.

what frame do you have baldman?
http://www.shop.18bikes.co.uk/news.php?articleid=78

It’s basically a third of a mil off the thickness of the post that… How much metal is there? Some manufacturers are happy with this sort of thing, Cove frinstance I think, but Giant don’t seem like the sort of company that designs frames with much extra metal in them.

Lots of rumouring on the gravity enduro FB that CYB is out, but tbh I don’t know if any of it is actually credible.

Cove Hustler – thank’s for link dirtbiker. 18 bikes seem confident about doing Coves 😀 still be good to hear some customer feedback, but think I’ll give them a call too.

Iv had my 30.0 Norco six reemed to 30.9 for a dropper.
2 years and 2 Megavelanche later its absolutely fine.

I decided that even with the reaming the wall thickness would still be greater than most other bikes. the Norcos are built for abuse!

Id do the same check that I did on wall thickness – then contact Argos cycles in Bristol if its close – they did a good job on mine for £50

My Last Herb has 34.9 OD and 31.6 ID
My Trance has 34.9 OD and 30.9 ID
So I’d have thought there would be space but not sure if others have tried this idea before.

Could you borrow a 30.9 adjustable post from someone for the event?

Or buy a s/h one and sell it after?

Seems like a massive faff to me otherwise, but I do appreciate the value of having one in those races.

Yeah – glad you can see my reasoning behind wanting one Chakaping, especially on a pedally course with several steep sections.

Think sourcing another for a few days might be the best way to go. Oooor buy a 27.2 dropper for my hardtail and shim it up for race weekend for the trance. There’s a plan.

Surely the guts of the Reverb are the same, so you’d just need to change the outer sleeve/casing? Have you tried talkig to TF Tuned about spare parts?

Reaming sounds like a good way to end up with a bust frame…

If I was on Facebook I’d simply “like” that comment but as it is I’ll have to write how that’s a very good point and I’ll have to do some research on that point. Thanks very much Jonedwards, working in manufacturing I should have realised that fact!

I have a 30.9 Reverb and my bike’s 31.6, I use an adaptor shim, I realise that doesn’t help you, but if you’re anywhere near Brighton maybe we could consider a swop?
email me – flatpedalthunder(at)gmail(dot)com

I would go with mudfish.

as mudfish said… i also have a 30.9 reverb i could swap

We’ve reamed out various frames (Cove, Transition, Santa Cruz) from 30.0 to 30.9, with 34.9 OD.

I’d not bother when you’ve already got 30.9mm, just swap the post/lower.

All TBC but it’s looking like:

Round 1- Afan
Round 2- Innerleithen
Round 3- Hamsterley
Round 4- Dyfi
Round 5- Triscombe

Definitely get a Reverb in. I did all 5 rounds last year without one and did alright but I’m sure I would have knocked a fair bit of time off with a Reverb.