Headset/headtube advice

[xerxes]

Hi all,

I have a 1990 Marin with a 1" threaded stearer. The problem is that the stearer tube is too short, so with most headsets the lock nut isn't even on the threads, so I sort of use the handlebar stem to hold it all together, in a similar fashion to a threadless headset. It works, sort of, but is hardly ideal.

On my frame the headtube extends a good 7 or 8mm above the top tube and below the down tube.

This isn't my frame, but illustrates what I mean:

I was thinking that, rather than try to find new forks with a longer steerer tube, I could have about 3mm taken off both the top and bottom of the headtube which would give me a fair bit more thread to play with on the steerer tube of my existing forks.

Does this sound OK, or is it a bad idea?

 

[hamster]

It will be hard to get the ends exactly square, after which the headset won't sit straight. Personally I'd wait and look for another fork rather than ruin a frame.

You can also ask a framebuilder to extend your steerer, or look around online:
Snazzy carbon ones for example:
http://www.carboncycles.cc/?s=0&t=2&c=82&p=966&

Or there are a fair few suspension forks around secondhand with 1" steerers on this site.

If the worst comes to the worst, a framebuilder will make you some for under £100.

 

[xerxes]

It will be hard to get the ends exactly square, after which the headset won't sit straight.

I wasn't thinking of going at it with a hand file, I was going to take it to a good shop and have then "face" it.

 

[hamster]

The facing tool is like a reamer - not designed for shaving off that amount of material. It would do it, but would take hours AND you might wear the tool out so factor it into the cost.

Have you tried low-stack headsets or alternatively using ahead with a steerer extension to accomodate the top?

 

[ishaw]

6mm doesn't sound like a lot so if currently the lock nut is nowhere near the threads I'd say you will still be in pretty much the same boat after a trim. The best solution is obviously a fork with a longer steerer tube or you could get some pace forks with a removable steerer so you can get the length you need. Or any of the above suggestions too.

 

[trail_head]

Also remember that cutting the bottom of the heat tube changes your bikes geometry. If you were going to do this, cutting it all from the top would be best. 1/2 as much work too.

 

[xerxes]

Also remember that cutting the bottom of the heat tube changes your bikes geometry.

I considered that, but then thought, 3mm is such a small amount that it's very unlikely to be noticeable, after all the geometry on a hardtail with 100mm+ suspension will vary hugely in comparison and people seem to manage. The head angle will vary by nearly as much with hard and soft tyres.

 

[trail_head]

Agreed! A small change in head angle to be sure.

How do propose to do the cutting?

 

[FMJ]

3mm is an awful lot to take off with the Park Tool. I'd find a machinist to do it on a mill. it's a 15 minute job.

And don't forget, if you remove material from the bottom of the headtube you run the risk of the crown/fork caps hitting the downtube. Manitou forks are the worst for this. The only solution if you remove too much material from the bottom is a + crown race, and the only company I know of that makes them for their headsets is Chris King (but that defeats the purpose of removing the material from the bottom in the firs place).

 

[xerxes]

I've actually contacted a frame builder that is fairly close to me to see if they can help: http://www.enigmabikes.com/index.html

They've been very helpful and asked me to send a couple of pictures, so I'll wait and see what they say.