Carbon fibre for fixed gear?

DadaKopf · 02-05-2009 6:37pm #1

Many of you know I'm currently embarking on a mission to build my own fixed gear bike. So, as with all obsessions, you do what you can to find yourself a nice frame or, perhaps, some nice components towards it along the way.

Today, something rather miraculous happened. I was given (yes, given) a carbon fibre road bike. Until I did some research, I didn't know anything about it.

It's a Look 'Hinault' Kg 76. I want to get the frame checked out but the important components all seem fine: brakes, hubs and rims, gear shifters will need work (or some replacements), although I've noticed the drivewheel doesn't spin so freely, maybe there's some problems with the bottom bracket.

So, my question is can I safely convert this thing to a fixed gear bike? And, even still, should I? I've heard some horror-stories about carbon frame conversions, I was wondering how mad the idea would be.

blorg · 02-05-2009 6:54pm

Nice, you are a lucky man indeed. If the bike is safe to ride as a geared bike you can ride it fixed I reckon, there are no magical extra forces fixed. Even skid stopping is not particularly rough on the frame. So it is just down to whether the frame is in good condition. I know someone who rides one of those old Looks (geared) and it still seems fine.

I want a carbon fixed bike myself, if I were you I would certainly do it (presuming you don't want it as a geared bike.) I note it has horizontal dropouts too which would be very rare on a carbon frame!

Morgan · 02-05-2009 8:37pm

DadaKopf wrote: »

gear shifters will need work (or some replacements)

On a fixed-wheel?

Thomas_S_Hunterson · 02-05-2009 8:53pm

Have you checked the dropouts?

rob1891 · 02-05-2009 9:01pm

from: http://sprockets.cc/?p=21

Fixed (its dropouts are fine for fixed) or geared, that will be some bike. You are very lucky!

The tax man · 03-05-2009 12:29am

DadaKopf wrote: »

Today, something rather miraculous happened. I was given (yes, given) a carbon fibre road bike. Until I did some research, I didn't know anything about it.

Are you the "jammy" bloke off the FBD insurance radio adverts?

Sweet..sweet frame.

Thomas_S_Hunterson · 03-05-2009 12:36am

Will make one fine fixie

DadaKopf · 03-05-2009 1:14am

The frame is nearly identical to the picture there. Some very slight differences in build, perhaps, but those horizontal dropouts are there alright. The main difference is the appearance - with this one, you can see the criss-cross carbon fibre weave and the decals are different (an updated Look logo, too).

I cleaned the thing today and no discernable cracks or stresses, just some superficial damage to the paintwork/decals/surface.

Another question, then: where's a good place to get it checked out?

The tax man · 03-05-2009 1:47am

DadaKopf wrote: »

The main difference is the appearance - with this one, you can see the criss-cross carbon fibre weave and the decals are different (an updated Look logo, too).

Reckon it's just that photo. You can just make it out the weave on the head tube.
Here's a close up
weave can be clearly made out. The frame I linked to was going for $1,200.

Are you Dublin based?

DadaKopf · 03-05-2009 2:02am

Yeah, that's it, but the artwork is different. I did come across that website when doing my post-find research! Yeah, I is Dublin.

DadaKopf · 03-05-2009 5:31pm

Problem detected: whoever had it before me, it appears that the aluminium seat post has either fused/rusted into the seat tube, or someone installed into the seat tube an inappropriately sized seat post. Now the whole thing's locked up. The lack of a seat post nut makes me wonder...

Have found limited info on how to remove. It seems WD-40 may damage the frame.

Caroline_ie · 03-05-2009 5:38pm

'Frenchie' has the same frame or something very similar. I am not sure what he posts under, if at all. Frenchie is you read this ...

blorg · 03-05-2009 6:00pm

Maybe do some more research on it before you try but you might be fine with WD40. You may find mixed views on this one.

Alternately maybe try wrapping ice around the seatpost to cool it? Cool=shrink. You could also try lightly heating the frame with a hairdryer to expand it.

Clamping the post in a vise and trying to use the frame as a lever might also be worth trying.

steinone · 03-05-2009 10:21pm

I was told today that vinigar works well for unseizing seatposts.
If that doesnt work ammonia apparently eats through alu corosion.

DadaKopf · 04-05-2009 11:55am

I dunno, I think it'll have to be cut out. I've read about it, anyone have any tips?

Thomas_S_Hunterson · 04-05-2009 11:57am

DadaKopf wrote: »

I dunno, I think it'll have to be cut out. I've read about it, anyone have any tips?

Sounds like it's too much hassle for a busy person like yourself. I think you should give me the frame.

petethedrummer · 04-05-2009 12:32pm

DadaKopf wrote: »

I dunno, I think it'll have to be cut out. I've read about it, anyone have any tips?

I cut an alu seatpost out of a steal frame at the end of last year after trying ammonia, WD40 and brute force with ratchet straps. It was slow and laborious but I wanted to be careful not to damage the frame. When I thought I had cut through, I got vice grips and yanked it out with a lot of effort.

flickerx · 04-05-2009 3:26pm

DadaKopf wrote: »

I dunno, I think it'll have to be cut out. I've read about it, anyone have any tips?

I'd avoid cutting as much as possible. Use lots of any/all types of lube recommended here, and clamp the seat post in a bench vice grip, and slowly work the frame off it. That should do it.

Any more nice free frames knocking around???

DadaKopf · 04-05-2009 9:27pm

flickerx wrote: »

I'd avoid cutting as much as possible. Use lots of any/all types of lube recommended here, and clamp the seat post in a bench vice grip, and slowly work the frame off it. That should do it.

Any more nice free frames knocking around???

Thanks. No access to a vice. It's damn annoying. I put some WD-40 around the top of the post and let it there overnight to see if it would do anything. Nada. Then I shoved the saddle in between the balcony railingds and pulled, pulled, pulled.

Nothing.

Sorry, I'm dead-set on reviving this frame! I think I'll seek advice on cutting it.

No other nice frames knocking around, I'm afraid. Though I'm looking for a smaller old-fashioned, Dutch-style town bike to do up if anyone has an eye out.

steinone · 04-05-2009 10:18pm

sheldon brown

I have the same problem with my frame, steel frame and alu seatpost, tried vinigar, wd and other oil to no avail so far.
Havent got access to a bench vice or ammonia, if any of you fancy donating some ammonia it would be greatly appriciated.
Now someone said heating, what are those lugs made of? If they are steel dont heat it! Not sure about if they arent either, but alu heats and expands very quickly, more so than steel.

Any other tips on removing the seatpost?

DadaKopf · 04-05-2009 10:34pm

Freezing is another thing, it's all in Sheldon's article I suppose. But I was wondering more on the specifics which I haven't quite got my head around. As in, how to hold and get enough pressure on the hacksaw bit to cut a ridge through the post. I suppose you just can.

petethedrummer · 04-05-2009 10:35pm

steinone wrote: »

Havent got access to a bench vice or ammonia, if any of you fancy donating some ammonia it would be greatly appriciated.

Any hardware shop will have ammonia and its pretty cheap. Stinks though.

steinone · 04-05-2009 10:53pm

I have heard of other people doing it, taking hours to but getting it done.

I was thinking that if you leave a couple of cms of the exposed seatpost, cutting the rest off and cutting a v or a slit into the remaining stuck post.
If there is a slit in the frame to clamp the seatpost cut the seatpost through there too, get a vice grips and clamp hard on the post and pull. It might have contracted enough to move.

EDIT: Thanks Pete, how would you recommend applying the ammonia? It wont damage the paint or frame will it?

DadaKopf · 04-05-2009 10:54pm

I'll have a fun day tomorrow!

petethedrummer · 04-05-2009 11:26pm

Take the bottom bracket out and turn the frame upside down. Pour in the ammonia through the hole where the bottom bracket was. It didn't damage my paint work or the seatpost (but don't take that as a guarantee).

I don't know what it would do to carbon.

flickerx · 05-05-2009 2:04am

Surely one of your neighbours or mates has a bench vice in their garage or their shed? Ask around, loads of people have them for doing work on wood or metal. I'd also recommend going to your local secondary school or tech and they'll have one there in the workshops. Seriously, the bench vice gets any tricky muthafockah seatpost out of its tube.

petethedrummer · 05-05-2009 10:57am

It might be worth bringing the bikes to a shop. I'm sure they have done this numerous times. and it might be worth a few quid to get an expert to do it, especially for that pretty carbon frame.

steinone · 05-05-2009 11:51am

Thanks for the tip, I have tried a good few things but I will bring it down to my LBS, the thing is truely stuck not a mm of movement with me riding it unclmped, my 14.5stone self swinging from it while my bro does the oppisite on the other side.
I was out doing tricks on it yestereday, landed on the saddle so hard I bent the saddle rails from the saddle(which I cant get back in:( ) and not a bit of movement in the post.

blorg · 05-05-2009 12:44pm

petethedrummer wrote: »

It might be worth bringing the bikes to a shop. I'm sure they have done this numerous times. and it might be worth a few quid to get an expert to do it, especially for that pretty carbon frame.

This is a good suggestion, although you will probably have to waive all liability for possible damage (only reasonable with this sort of thing.)

Carbon fibre for fixed gear?

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