Shimano 105 Headset Threading and Swapping English / Italian Headsets
04-13-21, 11:04 PM
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Shimano 105 Headset Threading and Swapping English / Italian Headsets
I have a vintage Pinarello Montello that I presume is italian threaded (bottom bracket measures 70mm and I assume that if bottom bracket is italian the fork threading would be italian as well). It has a 105 headset that I was thinking of replacing with an italian threaded Campy chorus headset as it just looks better but I'm not so sure that the 105 headset on it currently is english or italian threaded. I suspect it might be english (the locknut markings indicate VF HP-1055 and what I think reads BG1). Is anyone able to confirm or advise on how to identify the different threading?
Also, I've read what seems to be conflicting information online. I've read that it is not advised to switch back to italian threaded headset if the italian threaded fork has already been threaded with an english threaded headset. On the other hand I've read that they are interchangeable. If the 105 headset is indeed english threaded and the fork italian threaded, how much harm would it cause to the fork threads if I swapped it back to an italian threaded campagnolo headset and just left it without ever going back?
Also, I've read what seems to be conflicting information online. I've read that it is not advised to switch back to italian threaded headset if the italian threaded fork has already been threaded with an english threaded headset. On the other hand I've read that they are interchangeable. If the 105 headset is indeed english threaded and the fork italian threaded, how much harm would it cause to the fork threads if I swapped it back to an italian threaded campagnolo headset and just left it without ever going back?
Last edited by PapaGanoosh; 04-14-21 at 01:26 AM.
04-14-21, 05:13 AM
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The only real differences are in the thread form - Italian is 55 degrees, English 60 degrees, and the crown race diameter, 26.5 versus 26.4.
If you have a steel fork and an aluminium headset there will be essentially zero damage to the fork from installing the headset[1], and the headset may have a tiny bit of change in thread profile if the tolerances are close enough that the fork acts as a forming tap. Even with a steel headset, I suspect that the actual differences will be hidden in manufacturing tolerances,
You are much more likely to have issues with stack height and the crown race diameter.
[1] to the extent that I have used a 26 tpi steel fork as a tap to convert some previously 24 tpi aluminium headsets to Raleigh-spec. No damage to the fork threads, headset now fits the (other) Nottingham fork.
If you have a steel fork and an aluminium headset there will be essentially zero damage to the fork from installing the headset[1], and the headset may have a tiny bit of change in thread profile if the tolerances are close enough that the fork acts as a forming tap. Even with a steel headset, I suspect that the actual differences will be hidden in manufacturing tolerances,
You are much more likely to have issues with stack height and the crown race diameter.
[1] to the extent that I have used a 26 tpi steel fork as a tap to convert some previously 24 tpi aluminium headsets to Raleigh-spec. No damage to the fork threads, headset now fits the (other) Nottingham fork.
Last edited by oneclick; 04-14-21 at 05:16 AM.
04-22-21, 10:12 PM
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The only real differences are in the thread form - Italian is 55 degrees, English 60 degrees, and the crown race diameter, 26.5 versus 26.4.
If you have a steel fork and an aluminium headset there will be essentially zero damage to the fork from installing the headset[1], and the headset may have a tiny bit of change in thread profile if the tolerances are close enough that the fork acts as a forming tap. Even with a steel headset, I suspect that the actual differences will be hidden in manufacturing tolerances,
You are much more likely to have issues with stack height and the crown race diameter.
[1] to the extent that I have used a 26 tpi steel fork as a tap to convert some previously 24 tpi aluminium headsets to Raleigh-spec. No damage to the fork threads, headset now fits the (other) Nottingham fork.
If you have a steel fork and an aluminium headset there will be essentially zero damage to the fork from installing the headset[1], and the headset may have a tiny bit of change in thread profile if the tolerances are close enough that the fork acts as a forming tap. Even with a steel headset, I suspect that the actual differences will be hidden in manufacturing tolerances,
You are much more likely to have issues with stack height and the crown race diameter.
[1] to the extent that I have used a 26 tpi steel fork as a tap to convert some previously 24 tpi aluminium headsets to Raleigh-spec. No damage to the fork threads, headset now fits the (other) Nottingham fork.
Just curious on everyone's thoughts on the state of the below campagnolo headset. Top seems to spin freely while the bottom still spins but bit more friction. Also, anyone able to ID this specific headset?
https://imgur.com/a/37a5q5u
