busted fork/steering tube

Welll.....my fault for getting cheap parts and not getting back to the mechanic when I could get reimbursed....but I'm not sure who did what to begin with.

I had a threadless to threaded converter (big rod with a chuck on the end) and it ate through my STEEL steering tube. I knew this might be a problem because a gasket seal ring, which was supposed to be on top of the headset nut, was inside the tube when I got it back from the LBS in 2009. I only discovered this after twisting the snot out of the allen bolt holding the converter on.

I let it go until last Sunday I was on Lake Cook road on the way to Lake Zurich and BINGO - my handlebars started to wobble and there was no pushing ahead. The converter chuck had broken through the steering tube wall and was rubbing against the inside of the head tube. It's not the headset, trust me.

So here is the fork:

SJS Fork (Dawes Galaxy Replacement)

I don't know if it's chromoly steel or hi-ten.

I haven't taken it apart. I just assume it's easier/cheaper to buy a Surly Cross Check fork and threadless headset and forget it.

▶ Reply to This

Replies to This Discussion

Permalink Reply by Legacy Frameworks on July 25, 2012 at 5:57am

Hi Matt, as a framebuilder I agree with Mark. When I build a fork, I choose a threaded steerer tube so that the threading will end just below the top adjustable race. Any threading below that is compromising the strength of the tube, not to mention the groove for the washer - which should end where the washer is below the locknut (or spacers).

Here are the steerers I usually get, they are only threaded for a few inches and are sold in increments of 60mm. http://www.cycle-frames.com/bicycle-frame-tubing/1-FORK-STEER-180mm...

This is one of the considerations I am taking into account when considering switching my frames to threadless.

▶ Reply

Permalink Reply by Doug Haynes on July 25, 2012 at 7:28am

All well and good when you are building a fork but not so easy when you have to purchase a pre-built replacement fork. A huge number of threaded forks on production bikes have fairly long threading as well and they don;t seem to have an issue...

The threading and key way do not create a significant weakness unless you are threading a steerer meant to be threadless. If the treads or key way caused significant weakness this sort of thing would be a much more common issue; I have seen it only one other time. Regardless of the threading on the fork the only thing that can cause that is significant over torque on the stem bolt. Somebody had to twist that thing WAY past proper torque to do that damage.

Legacy Frameworks said:

Hi Matt, as a framebuilder I agree with Mark. When I build a fork, I choose a threaded steerer tube so that the threading will end just below the top adjustable race. Any threading below that is compromising the strength of the tube, not to mention the groove for the washer - which should end where the washer is below the locknut (or spacers).

Here are the steerers I usually get, they are only threaded for a few inches and are sold in increments of 60mm. http://www.cycle-frames.com/bicycle-frame-tubing/1-FORK-STEER-180mm...

This is one of the considerations I am taking into account when considering switching my frames to threadless.

▶ Reply

Permalink Reply by Matt M. 18.5KM on July 26, 2012 at 4:22pm

Surly Crosscheck installed...brake functioning correctly....racks not installed....Can I put the Blackburn MTF-1 with the low rider FL-1 on the single fork-end eyelet? I've got the old version of the MTF-1 from back when they made them in Italy and didn't put any enamel on them. I like the stay for the low rider rack so I'd prefer to install that again rather than rely on the old high rider rack for stability.

For my fenders, would you say I should try putting the SKS mount on the inside of the fork blade at the inner mid-blade eyelet or at the eyelet on the fork end?