Bicycle Mechanics - 1" headset doesn't fit 1" fork or steerer tube

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kraftwerk
06-26-06, 02:06 PM
Did an inch used to be smaller? I have an original Cambrige Massachusetts built Merlin Mountain frame (circa 90's) with the 1" head tube. I can't seem to get ANY headset race to fit in the steerer tube. The races are just 32/nd of an inch too big. I have tried both a new threadless Ritchey, and an old Campy (threaded) headset as well as some other brand, all are one inch and all are a 32nd of an inch too big.
I have built up at least 10 bikes-- old new, both threaded headsets and thread less: Campy, Stronglight, Ritchey, Aheadset, Shimano, Mt bikes and road bikes,but this is just plain weird to me.... Any help would be appreciated. Also the fork race does not fit, by about the same 32nd of an inch.. too small to fit the fork, but that doesn't worry me as much as getting something to fit in the steerer tube. By the way I would like to set this up threadless but will go with anything that fits.
thanks.
Headset races come in 26.4mm and 27.0mm size. Make sure you get the right size. Also the frame cups are 30.0mm or 30.2mm... Measure EVERYTHING! :)
kraftwerk
06-26-06, 02:19 PM
thanks for the speedy reply! Sorry about the duplicate post, greasy fingers and all..
Your response makes total sense But why do they sell 1" headsets and not 30.0 and 30.2 mm or 26.4 and 27.0? Or do they? Is this a plot to get us to buy more stuff?
cyccommute
06-26-06, 02:30 PM
thanks for the speedy reply! Sorry about the duplicate post, greasy fingers and all..
Your response makes total sense But why do they sell 1" headsets and not 30.0 and 30.2 mm or 26.4 and 27.0? Or do they? Is this a plot to get us to buy more stuff?
The steer tube of some forks are 26.4 mm diameter and some are stepped up to a 27.0. You need to specify the steer tube diameter when you buy the headset. It's always just been done that way. It's dumb but... And there are lots of other examples that will bite you. For example, not all Shimano hub cones will fit in all Shimano hubs...even when they are all part of the same model line!
Don't try to force the 26.4 onto a 27.0 :eek: The races are rather brittle and will crack, especially if you give the race setter a mighty whack with a hammer. Don't ask me how I know this :o
thanks for the speedy reply! Sorry about the duplicate post, greasy fingers and all..
Your response makes total sense But why do they sell 1" headsets and not 30.0 and 30.2 mm or 26.4 and 27.0? Or do they? Is this a plot to get us to buy more stuff?Well, the only consistent sizing is the 1" steerer tube which have been around for over 100-years. During those years, different manufacturers in different parts of the world came up with different sizing standards to fit the crown-race and headset cups onto a bike. Such as the more recent BMX sizing of 32.7mm frame cups with a 1" steerer tube. The mix of sizing is even more convoluted now with introduction of 1-1/8" and 1-1/4" steerer tubes as well as the increased options between threaded and threadless. Just like death and taxes, you just accept and deal with it, you're not gonna change the system. Here's a good summary of headset sizing standards at the end of this Park Tool - THREADED HEADSET SERVICE (http://www.parktool.com/repair/readhowto.asp?id=127) page.
If you don't have one of these:
http://www.parktool.com/images_inc/repair_help/fork19.jpg
You really don't want to be working on headsets yourself.
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