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thinpin
02-22-2012, 05:17 PM
I'll soon be building up a Merckx Corsa TSX. What headset is required,
ISO/english or italian? I understand they are generally interchanable. Anyone know of any pitfalls I might encouter in selecting the headset.

oldpotatoe
02-22-2012, 06:39 PM
I'll soon be building up a Merckx Corsa TSX. What headset is required,
ISO/english or italian? I understand they are generally interchanable. Anyone know of any pitfalls I might encouter in selecting the headset.

Probably English but have a decent bike shop run a Campagnolo dye over it and it will be fine

Peter P.
02-22-2012, 07:02 PM
While the thread pitch is the same for English and Italian, the thread profile is slightly different. In practice, either will work.

The real difference appears in the press-fit dimensions. Japanese and English headsets have a smaller O.D., 30.0mm.

Italian headsets have a larger O.D., 30.2mm.

A sharp bike shop can measure and tell you what you need. Otherwise, I'd operate this way: If the BB threads are Italian, use an Italian headset. If they'r English, use an English headset.

Also, the fork crown race diameters are different and not interchangeable.

Japanese/English: 27.0mm.
Italian: 26.4mm.

Most headset fork crown races have their diameter stamped on the underside. The fork crown shoulder is easier to measure with a vernier than the I.D. of the headtube because the difference is greater. I'd use this number to determine which headset you need because it'll be easier to see on the vernier.

thinpin
02-22-2012, 07:18 PM
So merckx steel frames do not use a single style? The BB on this is italian.

champ
02-22-2012, 07:45 PM
I have an ISO Mavic headset on my MX-Leader with no issues. The same HS also threaded onto a Corsa Extra fork so I would assume an ISO HS will work fine on your frame as well.

zmudshark
02-22-2012, 09:18 PM
Question-- Why does anyone post after oldpotatoe gives the definitive answer?

What a resource Peter is. Listen and learn.

retrogrouchy
02-22-2012, 11:08 PM
What is an ISO headset?

Your Merckx will need a standard non-oversized Italian-thread (25.4 x 24) headset.

You will need to measure how much stack height is available.

Stack height is basically how much steerer protrudes when you slip the bare fork through the head tube. Once you have the available stack height, you can consider which headset(s) will work.

Most traditional non-oversized headsets have stack heights between about 32 and 42 mm. approx.

You fork's crown race and your head tube's I.D. will be the 'professional standard' of 26.4 and 30.2 mm, respectively.

thinpin
02-23-2012, 06:28 AM
Probably English but have a decent bike shop run a Campagnolo dye over it and it will be fine
I'd not even try to fit it myself. I'll be getting a local wrench (as opposed to wench) to prep the frame fully and fit the headset. He will also build the wheels. The rest I'll do myself - cant let him have all the fun. thanks for the tip.

oldpotatoe
02-23-2012, 08:30 AM
I'd not even try to fit it myself. I'll be getting a local wrench (as opposed to wench) to prep the frame fully and fit the headset. He will also build the wheels. The rest I'll do myself - cant let him have all the fun. thanks for the tip.

Yer welcome..BTW for the other post, 'English' HS fork crown race seats aren't 27mm.....

Peter P.
02-23-2012, 08:18 PM
Yer welcome..BTW for the other post, 'English' HS fork crown race seats aren't 27mm.....

According to the Sutherland's Manual, Japanese and English threading is the same, including a 27.0mm fork crown race.

There IS a footnote regarding the English fork crown race stating,

"Professional models are often manufactured using Professional/Campagnolo standard."

Note that it doesn't say "always". So either 27.0 or 26.4 dimension can apply but I take it to mean that lower quality English headsets may more likely adhere to the 27.0 standard. Problem is; where do you draw the line between Professional English headsets and lower tier headsets? Best to measure before installing.

retrogrouchy
02-24-2012, 04:01 PM
According to the Sutherland's Manual, Japanese and English threading is the same, including a 27.0mm fork crown race.

There IS a footnote regarding the English fork crown race stating,

"Professional models are often manufactured using Professional/Campagnolo standard."

Note that it doesn't say "always". So either 27.0 or 26.4 dimension can apply but I take it to mean that lower quality English headsets may more likely adhere to the 27.0 standard. Problem is; where do you draw the line between Professional English headsets and lower tier headsets? Best to measure before installing.

27.0 crown races are very, very rare, outside of old Frenchy and (some) Japanese stuff.

Your original post on this was confusing and incorrect as written, actually. My guess is that you read a book more than lived this stuff. Am I right? ;)

ultraman6970
02-24-2012, 04:16 PM
You can use either as long the crownrace is 26.4.

Italian and ISO/english threads are not the same but are so close that is not a problem to use one or the other one as long you are not playing in and out headset game 20 times each year.

In my particular case I always sell the frames with headsets, why? one is the headache to taking it out, secondly dont want the buyer to deal with the problem. 3rd, to buy a super busted headset SUCKS, specially with those old campagnolo ones that u can find at epay for 150 bucks and that have been at least in 30 bikes in the last 20 years.

Good luck.

ps: forgot this, you could use a shimano also, shimano made some iso headsets, even a regular jis could fit but you need to get the right crownrace in 26.4,

Peter P.
02-24-2012, 07:56 PM
27.0 crown races are very, very rare, outside of old Frenchy and (some) Japanese stuff.

Your original post on this was confusing and incorrect as written, actually. My guess is that you read a book more than lived this stuff. Am I right? ;)

No; you are incorrect, actually. I wrenched in a shop for 10 years.

ultraman6970
02-24-2012, 08:42 PM
27.0 crown race is not rare at all. Ask that to all the japanese bikes moving around, even many bikes started like 27 and ended up in 26.4 when the fork crownrace area died and had to be fixed up.

No idea about french standards, dont care either :p

Oh forgot, I have a shimano 600 headset moving around that is ISO .

retrogrouchy
02-26-2012, 12:18 AM
No; you are incorrect, actually. I wrenched in a shop for 10 years.

That's nice. Sounded like you were just reading from a Sutherland's Manual, to me....

I'll say it again: the Merckx in question will need a 'professional standard' Italian-threaded headset. That means a crown race of 26.4 mm I.D. and head races of 30.2 mm O.D., plus threading of 25.4 x 24tpi. The only question mark is stack height.