Using threaded fork with ahead

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xroads

New Member
IS this possible?
I have a spare fork which is too long , and would need extra threading cut to use with a threaded headset. Can I use this threaded fork with a 1" ahead headset, after cutting it down to size? It would mean the stem clamping onto the threaded part. Possible, stupid or not recommended?
 

Steve Austin

The Marmalade Kid
Location
Mlehworld
You could try it, but it won't work... the steerer is never gonna grip enough
 

Monty Dog

New Member
Location
Fleet
There are two problems - either the bending load on the fork steerer will propagate a crack at a thread root, leading it to fail. Alternatively, the inside of the stem will fret on the threads, damaging it internally and leading that to fail too.
 

llllllll

New Member
I've ran a bike with a similar set up for years no problems. I used an A headset with a 1 1/8 stem and shim on to a threaded steerer. The shim takes away any problems with the stem fretting on the threads. My steerer tube was steel and never had any problems with cracking. I stopped running this set up when I got a new bike - the Aluminium frame of my old bike cracked at the drop out - I don't think it had anything to do with the stem :rolleyes:.
 

Tim Bennet.

Entirely Average Member
Location
S of Kendal
Yes, lots of modern stems that are sold as 'designed' to fit 1 inch steerers are actually the same 1 1/8" model, but with a aluminium shim included. I think you would be safe to use this arrangement with a steel threaded steerer tube.
 

pieinthesky

New Member
If it was me I would try it but only in conjunction with a 1" to 1 1/8" shim which as previously suggested will stop the threads damaging the stem.

How much are you going to shorten the steerer? Can you flip the stem or use a high rise stem and move it down and off or partially off the threaded section. The highest stresses on the steerer will be at the lower edge of the stem and if this is below the thread you will reduce the risk of a steerer failure due to the stress raising thread.
 

andrew_s

Legendary Member
Location
Gloucester
Monty Dog said:
There are two problems - either the bending load on the fork steerer will propagate a crack at a thread root, leading it to fail. Alternatively, the inside of the stem will fret on the threads, damaging it internally and leading that to fail too.

This is the serious problem, and it's even worse than broken handlebars when it does happen.
The only safe way to use a threaded fork with Ahead is to use a threaded headset with a quill to Ahead converter. It's not a proper ahead system, but it allows you to use the ahead stems.

You could also look at getting a framebuilder to replace the steerer with a suitable threadless one (steel fork only).
 

Dave5N

Über Member
Why do you want to? the old threaded system is much better.

I am convinced Ahead systems were introduced for the convenience of mechanics and teams, not ordinary people. You get a lot less adjustment but they are easier to maintain.
 
Dave5N said:
Why do you want to? the old threaded system is much better.

I am convinced Ahead systems were introduced for the convenience of mechanics and teams, not ordinary people. You get a lot less adjustment but they are easier to maintain.

A threadless set-up is lighter, stiffer, easier to service because it requires no specialist spanners or training, and because there is a huge reduction in labour/assembly costs is cheaper to make, to buy and to service. Its also safer.

Why is the threaded system so much better?
 

papercorn2000

Senior Member
If the steerer is threaded, it's a potential place for a crack to form and the tube to fail - with potentially very nasty results. I wouldn't.
 
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