Technical query re. cycle steerer threads

Older, Nottingham made, Raleigh bikes have a steerer thread of 26 TPI
rather than the standard 24 TPI.

The bearings, cups, washers and nuts associated with forks usually come
as a set and are called a Headset. I would try to buy/find a headset
that fits both the new forks and the old frame or simply stick with the
old forks if they are undamaged. There is also the 'stack height' of
the headset to consider - i.e. The new forks must have enough thread to
allow them to be fitted through the frame and the headset - Both frames
and headsets differ in the ammount of steerer required.

A reference of headset types, sizes & threads can be found here:
http://www.sheldonbrown.com/gloss_ta-o.html#threading . (You may have
to scroll down to Headset Threading)

in message <[email hidden]>,

(') said:

I hope someone can help out with a query relating to cycle mechanics!

I have a cheap mountain bike - nothing special, just the kind that
Halfords would sell for £150 or so. It's a Raleigh something or
other.

Anyway, I'm trying to change the forks - a straight swap of unsprung
forks for newer unsprung forks that I was given by a friend who
upgraded. I understand that that threaded part at the top of the forks
is called the steerer, that's what the question relates to.

Now largely obsolete; modern bikes don't have threaded steerers, but...

Quoted message said:

Both my old forks, and the new forks have a 1" steerer. I would
naively imagine then that I can simply swap them over. Oh no, tried
that. It seems they have different threads, so the big nut that screws
onto the top of the steerer won't screw onto the new forks.

So, my questions are: Does this big nut have a special name? I've
been searching ebay but can't find anything. Also, are there different
standard threads applicable to a 1" steerer? If so, how do I work out
which one I need so I buy the right one?

The nut is called the headset lock nut, because that's what it is; for 1"
steerers the ISO standard is 24 threads per inch. Sheldon Brown says
Raleigh bikes used a proprietary standard of 26 threads per inch, so
presumably one of yours is ISO and the other is Raleigh.

Apart from the ISO and Raleigh standards mentioned above, Sheldon also
lists Italian and JIS standards for 1" threaded headsets, but as both
are 24 threads per inch the locknut should be interchangeable with ISO.

Quoted message said:

This all seems a bit confusing, I would have thought manufactuers would
have standardised

They have standardised - on threadless headsets.

Quoted message said:

- or does my Raleigh just have an oddball arrangement? TIA.

By modern standards, very oddball. By the standards of ten years ago,
moderately oddball.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

...but have you *seen* the size of the world wide spider?

Quoted message said:

Older, Nottingham made, Raleigh bikes have a steerer thread of 26 TPI
rather than the standard 24 TPI.

The bearings, cups, washers and nuts associated with forks usually come
as a set and are called a Headset. I would try to buy/find a headset
that fits both the new forks and the old frame or simply stick with the
old forks if they are undamaged. There is also the 'stack height' of
the headset to consider - i.e. The new forks must have enough thread to
allow them to be fitted through the frame and the headset - Both frames
and headsets differ in the ammount of steerer required.

A reference of headset types, sizes & threads can be found here:
http://www.sheldonbrown.com/gloss_ta-o.html#threading . (You may have
to scroll down to Headset Threading)

Thanks for your advice. If I'm right the ebay auction below should
work with the new forks?

http://cgi.ebay.co.uk/BANKRUPT-BIKE-HEADSET-FOR-1-THREADED-FORKS-NO-RESERVE_W0QQitemZ7234969348QQcategoryZ56194QQrdZ1QQcmdZViewItem

... I don't want to stick with the old ones as the fixing for the brakes
has sheared on one side, so no front brakes!

Simon Brooke said:

in message <[email hidden]>,

(') said:

I hope someone can help out with a query relating to cycle mechanics!

I have a cheap mountain bike - nothing special, just the kind that
Halfords would sell for £150 or so. It's a Raleigh something or
other.

Anyway, I'm trying to change the forks - a straight swap of unsprung
forks for newer unsprung forks that I was given by a friend who
upgraded. I understand that that threaded part at the top of the forks
is called the steerer, that's what the question relates to.

Now largely obsolete; modern bikes don't have threaded steerers, but...

Quoted message said:

Both my old forks, and the new forks have a 1" steerer. I would
naively imagine then that I can simply swap them over. Oh no, tried
that. It seems they have different threads, so the big nut that screws
onto the top of the steerer won't screw onto the new forks.

So, my questions are: Does this big nut have a special name? I've
been searching ebay but can't find anything. Also, are there different
standard threads applicable to a 1" steerer? If so, how do I work out
which one I need so I buy the right one?

The nut is called the headset lock nut, because that's what it is; for 1"
steerers the ISO standard is 24 threads per inch. Sheldon Brown says
Raleigh bikes used a proprietary standard of 26 threads per inch, so
presumably one of yours is ISO and the other is Raleigh.

Apart from the ISO and Raleigh standards mentioned above, Sheldon also
lists Italian and JIS standards for 1" threaded headsets, but as both
are 24 threads per inch the locknut should be interchangeable with ISO.

Quoted message said:

This all seems a bit confusing, I would have thought manufactuers would
have standardised

They have standardised - on threadless headsets.

Oh. As usual I'm behind the times. Ho hum.

Quoted message said:

Quoted message said:

- or does my Raleigh just have an oddball arrangement? TIA.

By modern standards, very oddball. By the standards of ten years ago,
moderately oddball.

Ta. Looks like the solution is to invest some hard earned in a 1" 24
TPI headset locknut. Will try that and report back.

Your Raleigh would have to rather older than 10 to have the 26 tpi forks.
There are two nuts at the top of the headset ( top bearing) and one of them,
the top one, will not screw entirely onto the steerer. Even if it has the
right thread it has a lip which will stop it going down the thread. Below it
is the top part of the actual bearing. This should turn down the steerer
thread as far as you like. The steerer may not be the correct length. If it
is too long cut it (carefully). If i is too short you are buggered.
Mike Sales

Mike Sales said:

Your Raleigh would have to rather older than 10 to have the 26 tpi forks.
There are two nuts at the top of the headset ( top bearing) and one of them,
the top one, will not screw entirely onto the steerer. Even if it has the
right thread it has a lip which will stop it going down the thread. Below it
is the top part of the actual bearing. This should turn down the steerer
thread as far as you like. The steerer may not be the correct length. If it
is too long cut it (carefully).

Genius! Ashamed as I am to admit it, it turns out that it wasn't the
thread that was wrong, just that I was trying to screw the locknut down
too far onto an overlong steerer and as you pointed out (but I was too
blind to spot), it has a lip which was fouling and making me think the
thread was wrong.

A quick spot of hacksaw work this morning has shortened the steerer and
allowed me to assemble the complete assembly. Mind you, the lower
section of the handbars, the part that has a 45 degree cut across it
won't slip down fully into the new forks, so I've hammered it in as far
as it'll easily go and I now have rather taller bars.

I also spent longer fiddling about with the V brakes that it took to
get the forks on. Seemed very hard to get the right compromise between
not fouling the front wheel and actually making contact with the wheel
when the brake lever is pulled.

Still, it's all testament to my complete ineptitude with such things..
Really should have taken it to a bike shop.

The sun's shining now so time for a test and adjustment run! Thanks
for the assistance.

Quoted message said:

Mike Sales said:

Your Raleigh would have to rather older than 10 to have the 26 tpi forks.
There are two nuts at the top of the headset ( top bearing) and one of them,
the top one, will not screw entirely onto the steerer. Even if it has the
right thread it has a lip which will stop it going down the thread. Below it
is the top part of the actual bearing. This should turn down the steerer
thread as far as you like. The steerer may not be the correct length. If it
is too long cut it (carefully).

Genius! Ashamed as I am to admit it, it turns out that it wasn't the
thread that was wrong, just that I was trying to screw the locknut down
too far onto an overlong steerer and as you pointed out (but I was too
blind to spot), it has a lip which was fouling and making me think the
thread was wrong.

A quick spot of hacksaw work this morning has shortened the steerer and
allowed me to assemble the complete assembly. Mind you, the lower
section of the handbars, the part that has a 45 degree cut across it
won't slip down fully into the new forks, so I've hammered it in as far
as it'll easily go and I now have rather taller bars.

Eeek. I'm worried now, because there *are* two different sizes of stem
that could fit in a 1" steerer. Hammering a 22.2mm stem into a 21.1mm
steerer is not going to guarantee the longevity of the steering column,
or even your ability to get the stem back out again.

Quoted message said:

I also spent longer fiddling about with the V brakes that it took to
get the forks on. Seemed very hard to get the right compromise between
not fouling the front wheel and actually making contact with the wheel
when the brake lever is pulled.

And I'm worried some more, if you took off cantilever brakes and put on
V-brakes I'm surprised you got them adjusted at all, technically you
need different brake levers. If you've got very powerful but very
squishy brakes, you probably had canti-compatible brake levers. If
it's working okay, you're probably okay to leave it, but just be aware
that something as simple as pad wear could leave your brakes not
actually braking.

Marvin said:

Quoted message said:

Mike Sales said:

Your Raleigh would have to rather older than 10 to have the 26 tpi forks.
There are two nuts at the top of the headset ( top bearing) and one of them,
the top one, will not screw entirely onto the steerer. Even if it has the
right thread it has a lip which will stop it going down the thread. Below it
is the top part of the actual bearing. This should turn down the steerer
thread as far as you like. The steerer may not be the correct length. If it
is too long cut it (carefully).

Genius! Ashamed as I am to admit it, it turns out that it wasn't the
thread that was wrong, just that I was trying to screw the locknut down
too far onto an overlong steerer and as you pointed out (but I was too
blind to spot), it has a lip which was fouling and making me think the
thread was wrong.

A quick spot of hacksaw work this morning has shortened the steerer and
allowed me to assemble the complete assembly. Mind you, the lower
section of the handbars, the part that has a 45 degree cut across it
won't slip down fully into the new forks, so I've hammered it in as far
as it'll easily go and I now have rather taller bars.

Eeek. I'm worried now, because there *are* two different sizes of stem
that could fit in a 1" steerer. Hammering a 22.2mm stem into a 21.1mm
steerer is not going to guarantee the longevity of the steering column,
or even your ability to get the stem back out again.

Not sure about this - I need to reassess tomorrow as I didn't make it
out on my evaluation run. I had a thought today that maybe if I
slacken off the locknut I could get the stem further in. May try that.

Quoted message said:

Quoted message said:

I also spent longer fiddling about with the V brakes that it took to
get the forks on. Seemed very hard to get the right compromise between
not fouling the front wheel and actually making contact with the wheel
when the brake lever is pulled.

And I'm worried some more, if you took off cantilever brakes and put on
V-brakes I'm surprised you got them adjusted at all, technically you
need different brake levers. If you've got very powerful but very
squishy brakes, you probably had canti-compatible brake levers. If
it's working okay, you're probably okay to leave it, but just be aware
that something as simple as pad wear could leave your brakes not
actually braking.

Nope. I don't even know what cantilever brakes are, much less have
taken any off. The old forks and these new 'uns have V brakes so
that's what I've been fiddling with after changing the forks to get it
right. Won't be sure how squishy they are till tomorrow.