Reaming 2008 Bottlerocket seat tube from 30mm to 30.9

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Reaming 2008 Bottlerocket seat tube from 30mm to 30.9
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flag Kamiizoo
Posted: Feb 7, 2021 at 20:41 Quote
Is it possible to get it professionally reamed to 30.9? It has a 34.9 outer diameter, which is normal for 30.9 seat posts so I figure it wouldnt be any weaker than a normal 30.9 seat tube. I would shim a 27.2 if I was fine with 100mm of drop, but I am not. I want around 150mm. Any opinions and/or thoughts?
flag mrfrench2013
Posted: Feb 26, 2021 at 9:19 Quote
I did this to mine, no one would touch it. I ended up buying the reaming tool and then sold it after for a small loss. I found others who have done it as well and had no issues. I emailed transition and they said that it shouldn't be a problem but they obviously couldn't condone it. The outside diameter of other 30.9 seat tubes on other bikes is the same as the bottlerocket's seat tube diameter so your not weakening it anymore than it would be on another bike with a 30.9 mm seat tube. Ive been running a reverb dropper in the reamed seat tube for three years with zero issues. Just go slow and do it right.
flag mrfrench2013
Posted: Feb 26, 2021 at 9:21 Quote
Nice ride btw, post it in the bottle rocket picture thread, we need some more! https://www.pinkbike.com/forum/listcomments/?threadid=9430&pagenum=165#commentid6961678
flag Kamiizoo
Posted: Feb 26, 2021 at 12:07 Quote
I was thinking the same thing with the od being the same as other 30.9 seat tubes. A few frame builders said they would do it for like 200 bucks, but that's a bit too expensive imo. And I don't trust myself with doing it lol.
flag mrfrench2013
Posted: Feb 26, 2021 at 12:19 Quote
The tools can be bought for half that and its takes about 20 minutes, lube it with some oil and turn it like your tapping a thread, turn and back out turn and back out etc... these are what i bought. https://www.merlincycles.com/en-us/cyclus-seat-tube-reamer-92170.html?utm_campaign=googlebase-US&utm_source=googlebase&utm_medium=shopping&utm_term=Workshop+Tools&ucpo=33043 https://www.merlincycles.com/en-us/cyclus-handles-for-seat-tube-reamers-92184.html
flag Kamiizoo
Posted: Feb 26, 2021 at 15:02 Quote
I dont really trust myself do it well. I feel like I will mess up.
flag iliveonnitro
Posted: Feb 27, 2021 at 10:33 Quote
Kamiizoo wrote:
I dont really trust myself do it well. I feel like I will mess up.

Very difficult to mess this up. You're only shaving 0.9mm in diameter, which isn't a lot. Aluminum would be pretty easy, steel would be a little tougher, titanium would be brutal. I would try to find an adjustable reamer so you can do it in 2 shots. It would give you more flexibility to adjust the exact diameter, too.

https://www.amazon.com/Mxfans-29-5-33-5mm-Cutting-Adjustable-Operated/dp/B07DR2TYPC
https://www.amazon.com/HHIP-2006-0087-16-1-11-Adjustable-Reamer/dp/B0742N8LKW

I would do it upside down or sideways, and you probably should pull the bottom bracket. The oil and metal shavings need to be cleaned out. If you're that nervous, buy the bit and bring it to a local machine shop. They'll probably charge you $100-200 in labor, though. I would personally do it myself.

If you have a local frame builder/hobbyist, he'll probably have a reamer.
flag Tombonombona
Posted: Mar 23, 2021 at 20:50 Quote
Another tip. Don't turn it backwards like you would with a tap. It will wreck the cutting edge. Source, machinist
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