'84 Bridgestone headset replacement size, help me out
03-25-07, 05:59 PM
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'84 Bridgestone headset replacement size, help me out
im looking to replace the headset on my 84 bridgestone. the stock one currently on it is a ugly looking, steel, no name that is hard to adjust properly (possibly a nikyo headset?).
My question is would anyone happen to know if the cups, and crown race are ISO, or JIS sized? i have a NOS '84 Shimano 600 ex headset that is ISO that i want to put on the bike ( i think the 600 ex is ISO, i havent seen any JIS ones).
Thanks
'84 Bridgestone 500
My question is would anyone happen to know if the cups, and crown race are ISO, or JIS sized? i have a NOS '84 Shimano 600 ex headset that is ISO that i want to put on the bike ( i think the 600 ex is ISO, i havent seen any JIS ones).
Thanks
'84 Bridgestone 500
03-25-07, 06:09 PM
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The only part you need to wonder about is the fork crown race: it's either 26.4mm ID (ISO) or 27mm ID (JIS) all the other parts are going to fit between one inch threaded Japanese forks with BSC (English) threading. (Or for that matter Italian threading) Measure with a digital caliper or do the "go/no-go" test: it either fits or it don't. Then you have the stack height to match, but you can usually compensate with spacers, either adding or subtracting them.
03-25-07, 06:14 PM
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can i just measure the fork steerer tube? or do i have to pop off the old
crown race and measure around the base where the race actually sits? i wanted to avoid even taking it apart if it was JIS.
crown race and measure around the base where the race actually sits? i wanted to avoid even taking it apart if it was JIS.
03-25-07, 06:41 PM
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Originally Posted by intron
can i just measure the fork steerer tube? or do i have to pop off the old
crown race and measure around the base where the race actually sits? i wanted to avoid even taking it apart if it was JIS.
crown race and measure around the base where the race actually sits? i wanted to avoid even taking it apart if it was JIS.
03-25-07, 06:58 PM
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If you have a set of dial calipers you can probably measure it without having to pop the crown race off. Or if it's hard to adjust you may just need a new set of bearings.
03-25-07, 08:38 PM
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The original headset is a Tange MA-60, which is classified as a Campy/JIS type fit. It fits a standard 30.2mm headtube, but the crown race is a 27.0mm. The stack height is an extremely short 31.2mm. It's a real oddball. Luckily, you can still get them from Harris Cyclery for $12.95.
03-25-07, 08:54 PM
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Hey thanks for the replies.
Dirtdrop, are you 100% sure the headset is JIS?
the one on my bike has no name, and it has zig zag cuts on the adjustable cup that "locks" it in. i know i am not describing it right., and you have to use vise grips on one cup, and a regular wrench on the locknut. The only info i found was at Sheldon's web site for a '85 500 and it is a Nikyo headset.
on the web i found an image for a "passage" ma-60 headset and it looks nothing like the cheapo one on my bike. the one listed at harris has no pic for reference.
Dirtdrop, are you 100% sure the headset is JIS?
the one on my bike has no name, and it has zig zag cuts on the adjustable cup that "locks" it in. i know i am not describing it right., and you have to use vise grips on one cup, and a regular wrench on the locknut. The only info i found was at Sheldon's web site for a '85 500 and it is a Nikyo headset.
on the web i found an image for a "passage" ma-60 headset and it looks nothing like the cheapo one on my bike. the one listed at harris has no pic for reference.
03-26-07, 06:54 AM
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I didn't say it was JIS. My reference says it's ISO with a JIS crown race. The '84 Bridgestone brochure lists an MA-60 headset for the 500. Bikes aren't always equipped as shown in the brochures. Parts get replaced. That's why asking on a forum is not the best way to find out which headset you need.
03-26-07, 11:01 AM
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I replaced the headset on my '84 Bridgestone 400 with a Shimano 600 with no problem. I don't know the year of the 600, but I did it probably 15 years ago. I assume the specs between the 400 and 500 should be similar and your old headset sounds like my original.
03-26-07, 11:46 AM
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i guess i will just try it and find out, thanks unworthy, vpiuva, dirtdrop, and badger.
dirtdrop,any chance you would be able to post a scan of that catalog?
dirtdrop,any chance you would be able to post a scan of that catalog?
03-26-07, 05:12 PM
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Originally Posted by badger_biker
I replaced the headset on my '84 Bridgestone 400 with a Shimano 600 with no problem. I don't know the year of the 600, but I did it probably 15 years ago. I assume the specs between the 400 and 500 should be similar and your old headset sounds like my original.
The old 600 headsets had a stack height of only about 33mm so it was an easy replacement. Current 1" threaded headsets are typically 37-40 mm so you may have problems finding a good short stack headset.
03-27-07, 12:56 PM
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Originally Posted by Dirtdrop
I didn't say it was JIS. My reference says it's ISO with a JIS crown race. The '84 Bridgestone brochure lists an MA-60 headset for the 500. Bikes aren't always equipped as shown in the brochures. Parts get replaced. That's why asking on a forum is not the best way to find out which headset you need.
