handlebars on fixed and track bikes
- Thread starter bonj2
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Amanda P
Legendary Member
- Location
- York. Well, York-ish...
Most DT lever bosses are simply brazed onto the outside of the frame tube. Soften the brass with your oxy-acetylene torch, pull the boss off and file away any remaining brass and you're done.
I've come across some on cheap frames which are spot-welded. These need to be ground off and then all traces of the weld carefully filed away.
This is a 531 frame, though, and too thin and delicate to be welded, so it won't have spot welds.
Some bosses fit into holes in the frame tube, but the holes are smaller than the external part of the boss. Same procedure; soften the brass and pull out the boss. Fill the remaining hole with brass.
(Liquid brass is quite clingy, and forms nice curves and miniscuses, so that's not as hard as it sounds. This is pretty much how lugged-and-brazed frames are built: the molten brass creeps into the tiny gap between the frame and the lug, filling it completely and alloying with the hot steel to make a very strong joing. Fillet-brazed frames require a slightly different technique, where the brass provides some strength by forming a fillet around the joint as well as filling the microscopic space between them - but again, the clinginess of the brass makes it form quite nice fillets without too much trouble, given a bit of skill on the part of the brazier. Any unevenness is filed away when it's cool. Anyway, where was I?...)
Oh, yes, then carefully file away any excess until it's flush. Brass is softer than steel, so that's not hard to do.
The scars of any of the above operations are more than adequately covered by re-finishing.
I'm confused about your confusion about the seat post clamp. The lugs on the seat tube may be rusty, but you're planning to re-finish it anyway, so no problem there - any rust will be removed. And there's plenty of rust elsewhere. It may be steel, but it takes a lot more rust than that to cause any structural weakness. (It's very rare indeed for a steel frame to fail from rust: cracks are much more common, and even they can often be fixed).
The other part of the clamp is, as you say, a bolt. Which is rusty. So buy a new stainless steel one.
This sort of work is everyday bread and butter stuff to any frame-building workshop. They might charge you £5 or £10 to remove bosses on top of the cost for re-finishing.
I've come across some on cheap frames which are spot-welded. These need to be ground off and then all traces of the weld carefully filed away.
This is a 531 frame, though, and too thin and delicate to be welded, so it won't have spot welds.
Some bosses fit into holes in the frame tube, but the holes are smaller than the external part of the boss. Same procedure; soften the brass and pull out the boss. Fill the remaining hole with brass.
(Liquid brass is quite clingy, and forms nice curves and miniscuses, so that's not as hard as it sounds. This is pretty much how lugged-and-brazed frames are built: the molten brass creeps into the tiny gap between the frame and the lug, filling it completely and alloying with the hot steel to make a very strong joing. Fillet-brazed frames require a slightly different technique, where the brass provides some strength by forming a fillet around the joint as well as filling the microscopic space between them - but again, the clinginess of the brass makes it form quite nice fillets without too much trouble, given a bit of skill on the part of the brazier. Any unevenness is filed away when it's cool. Anyway, where was I?...)
Oh, yes, then carefully file away any excess until it's flush. Brass is softer than steel, so that's not hard to do.
The scars of any of the above operations are more than adequately covered by re-finishing.
I'm confused about your confusion about the seat post clamp. The lugs on the seat tube may be rusty, but you're planning to re-finish it anyway, so no problem there - any rust will be removed. And there's plenty of rust elsewhere. It may be steel, but it takes a lot more rust than that to cause any structural weakness. (It's very rare indeed for a steel frame to fail from rust: cracks are much more common, and even they can often be fixed).
The other part of the clamp is, as you say, a bolt. Which is rusty. So buy a new stainless steel one.
This sort of work is everyday bread and butter stuff to any frame-building workshop. They might charge you £5 or £10 to remove bosses on top of the cost for re-finishing.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
bonj said:
Yes, it's called brass! See above long-winded answer.
Christopher
Über Member
[A-Team]Ah luve it when a plan kums togetha![/A-Team]
also, which of the following is correct?
* it's easy to take the headset off
* it's easy to put the headset back on again
* you need a special tool to do the above
* the quill stem has no direct connection to the headset, only to the steerer by virtue of friction caused by expansion
* the only purpose of the headset is to hold the forks to the headtube of the frame
* it's easy to take the headset off
* it's easy to put the headset back on again
* you need a special tool to do the above
* the quill stem has no direct connection to the headset, only to the steerer by virtue of friction caused by expansion
* the only purpose of the headset is to hold the forks to the headtube of the frame
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
126 mm was standard in the days of 5 and 6-speed screw-on freewheels. It could easily be sprung to take a 130mm hub, or cold-set.
In any case, fixed hubs usually come with a selection of spacers and washers that can be added or removed to suit the frame spacing, so fitting a fixed hub in it would be no problem.
Removing and re-fitting a headset is not difficult.
In any case, fixed hubs usually come with a selection of spacers and washers that can be added or removed to suit the frame spacing, so fitting a fixed hub in it would be no problem.
Removing and re-fitting a headset is not difficult.
RedBike
New Member
- Location
- Beside the road
Am I the only person who's completely shocked by this thread?
It wasn't so long ago that Bonj didn't see the point of fixed wheel bikes and wouldn't be seen dead on one!
It wasn't so long ago that Bonj didn't see the point of fixed wheel bikes and wouldn't be seen dead on one!
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
bonj said:
Yes, it'd be possible, but pointlessly extreme. It's not a hole you're ever going to notice - not like the DT lever bosses. Besides, one day you might want to fit mudguards.
You might want to remove the rear derailleur cable stop on the right hand chainstay though. And if you're determined not to have a back brake, you'd probably want to lose the cable guides on the top of the top tube.And yes, you could use axle spacers in that way, but the usual plan is to add or remove equal amounts of spacers from both sides, so that the wheel remains central relative to the frame.
Chain line is usually tweaked by varying bottom bracket axle length and choosing whether the chain ring is bolted on the inside or outside of the chainset spider. If you're really anal about it, you can put washers between the spider and chain ring. Some posh bottom brackets are adjustable so that you can tweak the chainline that way.
Yes, I am shocked. But I'm trying to be helpful and persuasive. Is it working?
RedBike
New Member
- Location
- Beside the road
!
see what you mean about it being anal to fill the back brake hole up, yes it would a bit wouldn't it. Would want to remove the cable stops though.
Bear in mind that i'm not living in sheffield at the minute, so the feasibility of a fixed is a lot higher. By the time i'm living in sheffield again, i might have got strong enough for it not to matter!
Bear in mind that i'm not living in sheffield at the minute, so the feasibility of a fixed is a lot higher. By the time i'm living in sheffield again, i might have got strong enough for it not to matter!
