Just cut down the steerer on my carbon road forks. The cut was below the height of the SFN and my plan was to use a Head Doctor type thing to re-tension the headset bearings. However, I’ve just discovered that my steerer tube features two SFN’s, presumably the factory banged one in too far. The second SFN needs to be about 1cm further down the tube, but I don’t know what the best way to do this?

Obviously my concern is that I don’t want to smash up the forks and also that I want to go for a pedal while the sun is out.

Cheers

you shouldn’t have a SFN on a carbon steerer

options:
bang it in lower
or drill it out

is it a carbon steerer?

if so the factory won’t have fitted an SFN – they’d be sued when the steerer tube failed and their customers died.

assuming the steerer is not carbon go to lbs and they will whack it down with the tool for the job in seconds. you could bodge it yourself but the chances of getting it straight are below average

If it’s an alu steerer, then just screw in the the bolt which you use on the top cap and bash it down as far as you need it to go with a hammer, hitting it straight.

If it’s a carbon steerer, get some new forks.

If it’s an alu steerer, then just screw in the the bolt which you use on the top cap and bash it down as far as you need it to go with a hammer, hitting it straight.

If it’s a carbon steerer, get some new forks.

+1

Sorry, carbon forks with alu steerer. I’ve done SFNs loads of times, no issues with putting the bolt in and bashing it, that’s what I’d normally do.

My question was really how should I support the forks? Drop outs onto some carpet, put the wheel in to support the forks, or support under the arch with a block of wood or something else?

Just hold it under the crown.

I stick all mine in a vice, lightly clamping the steerer.

Support under the arch/crown – don’t bang it down onto the dropouts. Given the SFN is already fitted, you shouldn’t need much force.

what’s the best thing to use on a full carbon fork?

My road bike has a hope headset, so I’m guessing they may have used the hed doctor.

One of the great ‘old stw’ wind-ups was the ‘Help, I’ve bashed the sfn into my carbon SID steerer at a funny angle’ thread

ah, happy days.

All sorted, SFN was only half in (Due to location of saw cut) so did take a bit of a bashing, but nothing excessive. Only had to move it about 5mm as I could tell once the top flanges were in it would have enough purchase to do the bearings off. So much better looking without that daft inch of spacers above the stem!

I’ve asked about carbon steerers before and the recommendation at the time was to go with the manufacturers own bit of kit. The Kinesis one is pretty good though. I’d imagine you’ll have the manufacturer’s thing to match the fork rather than to match the headset.

I hold the fork with my legs and then guide the setting tool with my free hand it avoids damaging the dropout tips.