Solution for mis-sized fork crown race

trg said:

I am changing forks. The old fork has a 27mm crown race support. The new one
has a 26.4mm support. So the old crown race is loose on the new fork. What
pieces do I have to replace to use the new fork instead of the old? Is there
some kind of shim I can use instead of replacing anything?

Thanks,

-Tom

No shim, see a LBS and see if that hs has a 26.4mm fork crown race or
get a new headset.

trg said:

I am changing forks. The old fork has a 27mm crown race support. The

new one

Quoted message said:

has a 26.4mm support. So the old crown race is loose on the new fork.

What

Quoted message said:

pieces do I have to replace to use the new fork instead of the old?

Is there

Quoted message said:

some kind of shim I can use instead of replacing anything?

I had a similar situation and shimmed my crown with a bit of aluminum.
It worked fine.

trg said:

I am changing forks. The old fork has a 27mm crown race support. The new one
has a 26.4mm support. So the old crown race is loose on the new fork. What
pieces do I have to replace to use the new fork instead of the old? Is there
some kind of shim I can use instead of replacing anything?

That's the main load-carrying bearing for the fork; I wouldn't use a
shim there unless it was a machined steel collar made for the purpose.
It would cost more than the price of a new headset to get such a
collar made. If you know the brand of headset, there's a slim chance
that just the crown race might be obtainable in the new size. If this
is an older Japanese bike, your options are not as wide as they are if
it's an Italian or French bike. For Japanese JIS-headset bikes, the
best you can hope for is to find a crown race in the junk box at your
lbs which will fit the new steerer and work with the old bearings; you
may also need to find an upper bearing and nut that will work with the
JIS cup in the head tube; sometimes the JIS-threaded uppers won't
thread on to an ISO-threaded tube properly. For the Italian and
French bikes, a regular ISO headset (readily available, generally not
expensive) will do the trick.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Peter Cole said:

trg said:

I am changing forks. The old fork has a 27mm crown race support. The

new one

Quoted message said:

has a 26.4mm support. So the old crown race is loose on the new fork.

What

Quoted message said:

pieces do I have to replace to use the new fork instead of the old?

Is there

Quoted message said:

some kind of shim I can use instead of replacing anything?

I had a similar situation and shimmed my crown with a bit of aluminum.
It worked fine.

Shimming that much on a place where there is so much force rarely works
for long. Just get the proper fork crown race or new HS. Good HS',
installed onto properly prepped frames and forks are cheap, last
forever. Expensive HS' make little sense to me.

Werehatrack said:

trg said:

I am changing forks. The old fork has a 27mm crown race support. The

new one

Quoted message said:

Quoted message said:

has a 26.4mm support. So the old crown race is loose on the new

fork. What

Quoted message said:

Quoted message said:

pieces do I have to replace to use the new fork instead of the old?

Is there

Quoted message said:

Quoted message said:

some kind of shim I can use instead of replacing anything?

That's the main load-carrying bearing for the fork; I wouldn't use a
shim there unless it was a machined steel collar made for the

purpose.

You imply there's a safety issue with using a shim. What failure mode
do you predict to justify that concern?

"Qui si parla Campagnolo" <[email hidden]> a écrit dans le message de
news:1113570229.7ada903a5834bc9b853ec19900d3bf7b@teranews...

Quoted message said:

Peter Cole said:

trg said:

I am changing forks. The old fork has a 27mm crown race support. The

new one

Quoted message said:

has a 26.4mm support. So the old crown race is loose on the new fork.

What

Quoted message said:

pieces do I have to replace to use the new fork instead of the old?

Is there

Quoted message said:

some kind of shim I can use instead of replacing anything?

I had a similar situation and shimmed my crown with a bit of aluminum.
It worked fine.

Shimming that much on a place where there is so much force rarely works
for long. Just get the proper fork crown race or new HS. Good HS',
installed onto properly prepped frames and forks are cheap, last
forever. Expensive HS' make little sense to me.

I found a 26.4 crown race that works ok. But I don't see how a shim could
fail. Given the installation and direction of force it's not gonna work
itself loose. Seems that a slice of a coke can woulda worked ok too.

trg said:

I found a 26.4 crown race that works ok. But I don't see how a shim

could

Quoted message said:

fail. Given the installation and direction of force it's not gonna

work

Quoted message said:

itself loose. Seems that a slice of a coke can woulda worked ok too.

Yes, I'm quite sure I used Coke, not Pepsi. I don't see how it will
come loose either, if it does, no biggie, wouldn't be my first ride
with a loose headset, somehow I doubt it will, shimmed cranks have held
without problem. My seatpost and handlebar and aerobar are shimmed, the
original seatpost shim was plastic. I replaced it after a couple of
years for cosmetic reasons, but it held. I weigh 235, BTW.

trg said:

Quoted message said:

Quoted message said:

Shimming that much on a place where there is so much force rarely works
for long. Just get the proper fork crown race or new HS. Good HS',
installed onto properly prepped frames and forks are cheap, last
forever. Expensive HS' make little sense to me.

I found a 26.4 crown race that works ok. But I don't see how a shim could
fail. Given the installation and direction of force it's not gonna work
itself loose. Seems that a slice of a coke can woulda worked ok too.

Aluminum shims from coke cans are soft and eventually will compress or
deform to the point of making for a loose fork crown race..IME.I think
the proper part for the job rather than a interim fix..but this from a
bike shop where shimming with coke or even beer cans is not the way to
fix it.