Aardwolf

Hiya folks,
I'm about to replace my headset and there's one item I'm not sure about: 'hammering' the crown race into place.

I've read Sheldon Brown and he says put a pipe over the steerer and tap on it.
Other people say put a pipe (PVC, mild steel etc) over the steerer and bang the pipe against the ground.

My question is: why don't people just use a short length of pipe (about 6") and tighted down the locknut against it ?

Andrew R Stewart 

The pipe to be pressed down by the lock nut will need to be a fairly exact length. So one would need to make the pipe anew for every bike they do this job on. The amount of force to press the crown race on can be more than what the steerer/lock nut threads are made to handle. Shock does a better job at this job than mere pressure will do and can be faster to attain. What will one do if the fork is threadless? Andy

Aardwolf

Cheers.
That's the bit I was concerned about, probably better to follow what Sheldon said then

As far as I can remember there's about 3" of thread on my forks.
And I agree it doesn't apply to threadless forks, but I don't have any such modern devices.

dedhed

Verify your crown race and seat are both the same i.e. ISO and JIS diameters are different.

FBinNY 

It's mainly a question of good use of time.

Instead of crapping around with more tools, ie. a wrench for the lockout, and trying to tighten it while holding the fork, you can simply use the pipe you need anyway as a slide hammer and be done.

Plus the slide hammer method offers positive confirmation that the crown is seated via a change in the sound.

Andrew R Stewart 

With about 3" of threading on your fork I am concerned about the stem's wedge sitting within that threaded portion. That would be bad and most fork makers won't warranty the fork after the stem expands and cracks the steerer. The threaded portion is vastly more prone to this than the rest of the steerer. As this portion of the steerer is out of sight and since the result of steering loss is so bad I strongly suggest that you make sure the stem wedge is below that threaded section. Andy

Aardwolf

Just checked and it's 45mm of thread and the wedge is just below that.
Also remembered that I checked the wedge position about a year back to make sure it was clear of the thread
Must be getting old or something.

gearbasher

This is the method I've always used without fail. Just tap it on by sliding the pipe up and down. It doesn't take much force.

Aardwolf

I had read about that and was fairly certain mine was ISO - it's a 1982 Holdsworth with an original Tange headset.

Fork measures 26.98
The removed crown race measures 26.8
The replacement (Tange Levin CDS) is 26.3

Rats, I'm guessing I need a JIS one.
Seems like this was known if I'd only looked: https://forum.cyclinguk.org/viewtopic.php?t=17078

Update: Tange Levin CDS also comes as JIS, but not as common.

dedhed

​​​​​​
You can buy Levin crown races separately.

​​​​​​https://www.somafabshop.com/shop/297...7-0-3444#attr=
https://www.retro-gression.com/produ...iki-crown-race

Schweinhund

and if you have a problem, you clamp the pipe in the vise and invert the fork into the pipe and place a block of wood between the fork blades and hammer lightly. I've used this method on old schwinn forks more than anything else.

Crankycrank

Also heating up the race in boiling water and if you have a large enough freezer, put the fork in there for a couple hours or put some ice around the race seat right before installing the race. Expansion/contraction trick makes it easier to get the race on.

soyabean

Hammering is exactly how it is done.

I use a rubber hammer.

I've found the softest ones are the cheap ones you find at places like Dollar General, but your choice to get a Park Tool HMR-4.

If the fork is too narrow, a soft piece of wood helps. Something like crappy cheap pine from pallets.

I admit there is some experience needed to constantly eyeball along every tap so it is going in evently, otherwise skewed.

I'm not sure if there can be any possible damage from an uneven seat, as I get it right all the time.

Aardwolf

This is an approach I like, it seems a bit more controlled.

grumpus

There's really no need for a hammer, piece of wood or whatever - using a steel tube as a slide hammer is quick and easy, you can hear/feel when the race is set properly, you don't risk damaging the paint because you're holding the fork in your hand and the movement of the hammer tube is constrained by the steerer. Just don't get overenthusiastic if it's a short steerer, as an unconstrained hammer tube will mess up paint quicker than you can say "oh dear" (alternatively you slam your pinky finger against the end of the steerer).

Aardwolf

Tange Levin JIS turned up today and I still couldn't get the crown race on.
Probably because I've only got a piece of plastic pipe - can't find a shop round here that sells the right diameter metal tube and
Amazon would take a week to deliver.

So I phoned the local LBS and walked it round there.
Harry at Elswood Cycleworks (Putney) fitted it in 15 seconds for free
He does have the right sized pipe.