French forks ?

anern said:

Hi,
Had some problems with stipped threads on the lock nut on by headset,
both second hand bolts but now I've decided to do the job properly I'm
concerned that I may have french forks. Sheldon's site says that the filed
bit on the back of the top of the fork threads is a french thing - everyone
else having a slot. The table on the site says this has a different TPI of
25.4 rather than the ISO standard 24. Photo here :

http://homepage.ntlworld.com/brucejlee/BikePhotos/P1000968.JPG

site page here

http://sheldonbrown.com/gloss_ha-i.html#headset

My LBS said maybe the thread on the fork was dodgey but it seems OK to me,
he recommended a 105 headset.

Also, are there different head tub diameters ? This is an old frame so would
a modern headset fit ?

Measure the stem - if 22.0, French. If 22.2, not French.

What's the make and age?

Quoted message said:

Quoted message said:

Hi,
Had some problems with stipped threads on the lock nut on by

headset,

Quoted message said:

Quoted message said:

both second hand bolts but now I've decided to do the job properly I'm
concerned that I may have french forks. Sheldon's site says that the

filed

Quoted message said:

Quoted message said:

bit on the back of the top of the fork threads is a french thing -

everyone

Quoted message said:

Quoted message said:

else having a slot. The table on the site says this has a different TPI

of

Quoted message said:

Quoted message said:

25.4 rather than the ISO standard 24. Photo here :

http://homepage.ntlworld.com/brucejlee/BikePhotos/P1000968.JPG

site page here

http://sheldonbrown.com/gloss_ha-i.html#headset

My LBS said maybe the thread on the fork was dodgey but it seems OK to

me,

Quoted message said:

Quoted message said:

he recommended a 105 headset.

Also, are there different head tub diameters ? This is an old frame so

would

Quoted message said:

Quoted message said:

a modern headset fit ?

Measure the stem - if 22.0, French. If 22.2, not French.

What's the make and age?

I haven't got anything to measure to that acuracy. I think the bikes a Claud
Butler touring bike which was why I was confused about the forks, the forks
may not be origonal - I think the bike may have been repainted.

anern said:

Hi,
Had some problems with stipped threads on the lock nut on by
headset, both second hand bolts but now I've decided to do the job
properly I'm concerned that I may have french forks. Sheldon's site
says that the filed bit on the back of the top of the fork threads is
a french thing - everyone else having a slot. The table on the site
says this has a different TPI of
25.4 rather than the ISO standard 24. Photo here :

http://homepage.ntlworld.com/brucejlee/BikePhotos/P1000968.JPG

site page here

http://sheldonbrown.com/gloss_ha-i.html#headset

My LBS said maybe the thread on the fork was dodgey but it seems OK
to me, he recommended a 105 headset.

Also, are there different head tub diameters ? This is an old frame
so would a modern headset fit ?

Sheldon in effect mentions the head tube diameter too on that table. It's
the same (or almost) as the Frame Cup Outside Diameter. You're likely to
have 30.2mm - which a modern 1" headset will fit.

Actually the head tube is a tiny bit smaller than the cup to get a press
fit.

~PB

In article <[email hidden]>, anern
[email hidden] says...

Quoted message said:

Hi,
Had some problems with stipped threads on the lock nut on by headset,
both second hand bolts but now I've decided to do the job properly I'm
concerned that I may have french forks. Sheldon's site says that the filed
bit on the back of the top of the fork threads is a french thing - everyone
else having a slot.

Plenty of standard forks have flats rather than slots - yours looks as
if it was filed by hand anyway, so probably a universal replacement or
hand built item.

Quoted message said:

The table on the site says this has a different TPI of
25.4 rather than the ISO standard 24.

Just measure and count.

Quoted message said:

Photo here :

http://homepage.ntlworld.com/brucejlee/BikePhotos/P1000968.JPG

site page here

http://sheldonbrown.com/gloss_ha-i.html#headset

My LBS said maybe the thread on the fork was dodgey but it seems OK to me,
he recommended a 105 headset.

If the adjustable race has been loose for a while it may have deformed
the thread, so it's undersize but still looks fine - take the fork out
and place a straight edge along the thread (or just feel it) to see if
it narrows where the race was.

Quoted message said:

Also, are there different head tub diameters ?

That's the "frame cup diameter" in Sheldon's table.

Quoted message said:

This is an old frame so would a modern headset fit ?

IME the crown race seat diameter isn't as standard as it should be on
some forks - if it's a loose fit you'll need to source another race or
complete headset, if it's tight don't press it too hard - it's supposed
to be an interference fit but some are oversized and you could break the
race.