Author Topic: Bent seat tube (Read 6092 times)

ammacopij72 · « **on:** July 08, 2018, 04:04 PM »

Just noticed I might have a bit of a disaster here, can't get the seatpost into the tube as there is a slight bend/kink in it. Any ideas on how to resolve this without destroying the (new) powder coat lads??

oldschoolace · « **Reply #1 on:** July 08, 2018, 04:15 PM »

difficult to put right. Easiest option is to find a slightly narrower post( they do vary in diameter from make to make) and live with it. Without cutting it out and fitting a new mast all I can think of is a well greased post knocked down which may straighten it a bit.... Or get stuck :/

ammacopij72 · « **Reply #2 on:** July 08, 2018, 05:22 PM »

Quote from: oldschoolace on July 08, 2018, 04:15 PM

difficult to put right. Easiest option is to find a slightly narrower post( they do vary in diameter from make to make) and live with it. Without cutting it out and fitting a new mast all I can think of is a well greased post knocked down which may straighten it a bit.... Or get stuck :/

Cheers fella, can't believe I didn't see it before getting it powdered.. The problem is compounded by the fact that I've had the layback powdered too..

Might try running some sandpaper down the tube to see if it makes it any better and then try the grease and rubber mallet technique, fingers crossed!!

Jon1971 · « **Reply #3 on:** July 08, 2018, 05:43 PM »

Quote from: ammacopij72 on July 08, 2018, 05:22 PM

Quote from: oldschoolace on July 08, 2018, 04:15 PM
difficult to put right. Easiest option is to find a slightly narrower post( they do vary in diameter from make to make) and live with it. Without cutting it out and fitting a new mast all I can think of is a well greased post knocked down which may straighten it a bit.... Or get stuck :/

Cheers fella, can't believe I didn't see it before getting it powdered.. The problem is compounded by the fact that I've had the layback powdered too..

Might try running some sandpaper down the tube to see if it makes it any better and then try the grease and rubber mallet technique, fingers crossed!!

I would try that first mate, fine sand paper or wire wool then like you say grease and a rubber mallet. Should sort it

Taipan · « **Reply #4 on:** July 08, 2018, 06:37 PM »

I had an old seatpost taken off a GT pro stickered up as a GT post,I stripped it of its powdercoat it didnt have a GT stamp? but the post is deffo thinner (still strong) than the ones available today,so bitd they must have been a lot thinner,so look around for an older post maybe?

oldschoolace · « **Reply #5 on:** July 08, 2018, 06:59 PM »

I have a couple of these

https://m.ebay.co.uk/itm/19mm-To-62mm-Car-Engine-Flexible-Shaft-Brake-Cylinder-Hone-Bore-Honing-Tool-2756-/263481728748?nav=SEARCH

The stones are too fine a grit to do anything but polish tubing but I fook them off and glue small strips of emery cloth to the 3 feet.
Work great on seat masts, quick, easy and reach further than you would ever put a post

ammacopij72 · « **Reply #6 on:** July 08, 2018, 08:06 PM »

Quote from: oldschoolace on July 08, 2018, 06:59 PM

I have a couple of these

https://m.ebay.co.uk/itm/19mm-To-62mm-Car-Engine-Flexible-Shaft-Brake-Cylinder-Hone-Bore-Honing-Tool-2756-/263481728748?nav=SEARCH

The stones are too fine a grit to do anything but polish tubing but I fook them off and glue small strips of emery cloth to the 3 feet.
Work great on seat masts, quick, easy and reach further than you would ever put a post

Fantastic mate, thanks for that!

deeman · « **Reply #7 on:** July 09, 2018, 08:12 AM »

What a fooker! I had the same on a RL-20 once.....it's nigh on impossible to spot! I ruined 1 seatpost before I realised what was up. I resorted to grease and mallet technique to get another one in. It never went down as far as I would have liked.....Hope you sort it somehow

Retrodan72 · « **Reply #8 on:** July 09, 2018, 08:40 AM »

Gutted for you Neil especially as you’ve taken so much time to make sure every detail is spot on with this build, but like Damo said, these things are virtually impossible to spot.

On the plus side, you’re an experienced bike builder and you’ve put it out there on

where others can offer advice from their experiences.

I think you’ll know what to do without damaging the powder.

Good luck fella

ammacopij72 · « **Reply #9 on:** July 09, 2018, 08:54 AM »

Cheers Lads, fingers crossed it turns out okay..... $:-\$

ammacopij72 · « **Reply #10 on:** July 09, 2018, 12:09 PM »

Quote from: oldschoolace on July 08, 2018, 06:59 PM

I have a couple of these

https://m.ebay.co.uk/itm/19mm-To-62mm-Car-Engine-Flexible-Shaft-Brake-Cylinder-Hone-Bore-Honing-Tool-2756-/263481728748?nav=SEARCH

The stones are too fine a grit to do anything but polish tubing but I fook them off and glue small strips of emery cloth to the 3 feet.
Work great on seat masts, quick, easy and reach further than you would ever put a post

Any specific grade of emery cloth mate?

oldschoolace · « **Reply #11 on:** July 09, 2018, 12:19 PM »

Depends on whats down there. A phone torch is handy to shine down the mast. I have used 120 grit in the past when i had a stuck glasfibre post but would say 180-240 would be a good starting point. Aim to go down the grades so the mast is nice and smooth then you are done
I used a 90 second araldite to bond the emery cloth, holds it well enough but is brittle enough to get off when you are ready for the next grade

Will bung a pic of mine up

oldschoolace · « **Reply #12 on:** July 09, 2018, 12:45 PM »

Here you go

ammacopij72 · « **Reply #13 on:** July 09, 2018, 12:55 PM »

WINI · « **Reply #14 on:** July 09, 2018, 01:13 PM »

Wait till you see my snapped off renthal in an early unstamped GT performer frame

ammacopij72 · « **Reply #15 on:** July 10, 2018, 11:15 AM »

Quote from: WINI on July 09, 2018, 01:13 PM

Wait till you see my snapped off renthal in an early unstamped GT performer frame

chubby · « **Reply #16 on:** July 12, 2018, 11:08 AM »

That snake post fitted fine, didn't notice a bend in there either Neil

Sent from my HTC One M9 using Tapatalk

MartyC · « **Reply #17 on:** July 12, 2018, 01:05 PM »

Quote from: WINI on July 09, 2018, 01:13 PM

Wait till you see my snapped off renthal in an early unstamped GT performer frame

A strong mix of caustic soda will have that out in about a week!

ammacopij72 · « **Reply #18 on:** July 12, 2018, 04:14 PM »

Quote from: chubby on July 12, 2018, 11:08 AM

That snake post fitted fine, didn't notice a bend in there either Neil

Sent from my HTC One M9 using Tapatalk

That's cos the snake post is bent too mate!

Fingers crossed Clint's idea will sort it out...

chubby · « **Reply #19 on:** July 12, 2018, 04:44 PM »

Ahhhhh fook

Honestly didn't notice either were bent ..

Sent from my HTC One M9 using Tapatalk

ammacopij72 · « **Reply #20 on:** July 13, 2018, 07:57 AM »

Quote from: chubby on July 12, 2018, 04:44 PM

Ahhhhh fook
Honestly didn't notice either were bent ..

Sent from my HTC One M9 using Tapatalk

not your fault mate, only a slight kink in the seat tube and never intended to use the snake post so didnt look at it that closely. I think the issue is being compounded by the new nitto seat post being powdered too...

Fingers crossed it's all okay after a bit of fettling

ammacopij72 · « **Reply #21 on:** July 17, 2018, 06:33 PM »

Gonna make an attempt on the seatpost tomorrow, but have now found another problem when putting the stem in. It looks like the casting on the inside of the fork is not very round and the stem post just jams up about 40mm from where it needs to be...

I'm thinking maybe reaming out the forks might sort it?

Just starting to piss me off now as was hoping to have this done for mk and I'm running out of weekends....

oldschoolace · « **Reply #22 on:** July 17, 2018, 09:16 PM »

Had the same problem when I was trying to install a linear bearing in a fork once to run a woody style roller cam. Ended up buying a blacksmiths bit with a reduced shank (about 7 quid)
Ran it in a corded drill on half speed with the forks in a vice. Went really slow at it so it didn't grab and it worked a treat if a little scary

ammacopij72 · « **Reply #23 on:** July 25, 2018, 03:11 PM »

the good news first....the sea post tube is now sorted!!

....and now the bad news....still working to getting material removed from inside the fork steerer tube thingy and it's a right pain in the arse.

Have been using a pillar drill fitted with a bar wrapped in 80 grade emery cloth in my lunchbreaks at work...taking forever but still hopefull to get this sorted and built for MK!

Retrodan72 · « **Reply #24 on:** July 25, 2018, 03:13 PM »

Quote from: ammacopij72 on July 25, 2018, 03:11 PM

the good news first....the sea post tube is now sorted!!

....and now the bad news....still working to getting material removed from inside the fork steerer tube thingy and it's a right pain in the arse.

Have been using a pillar drill fitted with a bar wrapped in 80 grade emery cloth in my lunchbreaks at work...taking forever but still hopefull to get this sorted and built for MK!

Yay for MK Neil mate, keep the faith.