Headset Help - Bridgestone RB-2

[dirtdigger88]

Hola mi amigos -

Time for a new headset for my 1993 RB-2. Ive been searching online for the correct one but at this point I give up and figured I will ask here -

My online searches have turned up "Italian sized" - ISO and JIS . . . I say WTH??

Yes I know I can take the bike apart and measure - Im lazy

thanks
Jason

[bikinchris]

Bridgestone should have a JIS headset as far as i remember. They where made in Japan. JIS means Japanese Industrial Standard and it refers to the ID of the crown race.

It is certainly not Italian or French.

[GregL]

Very likely JIS standard crown race. I replaced the headset on an MB-5 and had to cut down the fork crown from 27.0mm to 26.4mm to install the new crown race. To be 100% sure, you will have to pull the fork and measure the steerer at the crown.

Greg

[Ken Robb]

I agree that it is almost surely JIS but I'll bet Grant or one of the other guys at Rivendell can say for sure. They can probably sell you the right piece too.

[bikinchris]

Very likely JIS standard crown race. I replaced the headset on an MB-5 and had to cut down the fork crown from 27.0mm to 26.4mm to install the new crown race. To be 100% sure, you will have to pull the fork and measure the steerer at the crown.

Greg

Yes, the 27.0 is the JIS race standard. You cut it down to install an ISO crown race. Which is not hard to do.

[weisan]

hi dirt pal.

[oliver1850]

Cup size is also different: JIS is 30.0 and ISO is 30.2. If the Bridgestone is JIS and the cups are tight in the frame, I'd stick with a JIS headset. If they (or one) is loose, might be a good time to switch to an ISO headset.

[Corso]

My 92 RB-2 is sporting a Campy Athena headset.
Found the old box, all it says is BC1.

Can Campy-philes out there identify?

[mtechnica]

Measure with calipers, iirc you can get a tange jis headset.

[oliver1850]

My 92 RB-2 is sporting a Campy Athena headset.
Found the old box, all it says is BC1.

Can Campy-philes out there identify?

If it says Athena on the cups, it's 1995-1999. There were two models, with a new lower (36.5 mm) stack height introduced in 1998. 1995 and 1999 parts catalogs show only one crown race, so no JIS. Really don't think Campagnolo ever made JIS.

[dirtdigger88]

Ha now you see my struggle. Im thinking jis and make it work.

Weisan - hello my friend

[oldpotatoe]

Hola mi amigos -

Time for a new headset for my 1993 RB-2. Ive been searching online for the correct one but at this point I give up and figured I will ask here -

My online searches have turned up "Italian sized" - ISO and JIS . . . I say WTH??

Yes I know I can take the bike apart and measure - Im lazy

thanks
Jason

26.4mm fork crown race inside diameter..english threading on the fork steerer.

Measure the head tube length, end to end and then the fork steerer length, fork crown race seat to end of steerer..subtract steerer length from head tube length=headset stack heaight..look for one of those with above info.