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-   -   1981 Fuji Royale bottom bracket sizing help please (https://www.bikeforums.net/classic-vintage/1050675-1981-fuji-royale-bottom-bracket-sizing-help-please.html)

royale81 02-28-16 03:24 PM

1981 Fuji Royale bottom bracket sizing help please
 
Hi,

Apologies if I'm breaking protocol -
I posted this thread in "Bicycle Mechanics":
http://www.bikeforums.net/bicycle-me...placement.html

and folks were very helpful - however, I found new info and made some more measurements and I'm completely at a loss -

Briefly, I need to replace the spindle on my bottom bracket.
The only marking on the existing spindle is 2S, which I could not find in Sheldon's list,so I was working off of measurements - the closest I could come to the list in the charts was the Sugino 3N at 32-52-36 (120). I believe that would be ISO also.

However, I did just find the 2S in the Sutherland book, and the spec for it says:JIS, 32-50.5-37.5 (also 120).

It occurred to me that I've been trying to match this spindle, and I don't even know if it is the original or spec size.

So I measured the BB shell (I'm not sure why I had just assumed it would be 65 earlier) - The shell measures as 69.x mm - close enough to 70mm.

This throws me off, as the 2S spindle that's been in there for the past 20 years at least is clearly listed as for a 65mm shell.

Also I had assumed I have the most common English thread cups (I'm not changing them) so then it would have to be 65mm or 68mm.

Now, I don't know what spindle size to get to get the right clearances and front Der. reach - (The crankset is the original Fuji which from the spec sheet is Tourist 2AC)

I'm wondering if anyone has actual specs - or wouldn't mind measuring - and 81 Fuji Royale - BB shell and spindle size?

Am I seeing things, or did the Royale really have a 70mm bracket (and does that mean it's not English?)

Spindle length? A-B-C? Still 120mm total?

And finally, am I looking for ISO or JIS taper for the Fuji cranks?

Any help will be greatly appreciated -

Thanks- and apologies if I should have posted this in the Mechanics thread -

Mehelli

Velocivixen 02-28-16 03:44 PM

If the current spindle length works well with your crankset, simply measure the entire length of the spindle and that is your spindle length. I'm pretty sure that your bottom bracket is 68mm. &0mm bottom bracket shell widths were for Italian bottom brackets I believe. J.I.S stands for Japanese Industrial Standard, and given that Fuji is a Japanese brand it's likely that you need a JIS spindle that is the current length you have now.

Who made your cranks? It may say "Fuji" on them but typically someone else made them.

When you measure bottom bracket shell make sure you're not measuring the cups and use a digital caliper if you've got one. After painting of a frame there is "facing" which cuts off a little paint/metal from each end of the bottom bracket shell to ensure that both ends are parallel to one another.

dddd 02-28-16 09:14 PM

Any alloy crank labeled "FUJI" is a mid-range, two-piece crank made by Sugino with JIS taper. These correspond to "Sugino Maxy" dimensions.

An ISO bb needs to be about 5mm longer (2.5mm per side) to give the same mounted "chanline" spacing of the crankarms as a JIS bb. This because the ISO taper is slightly smaller/thinner.

I would first test-fit using an English-threaded, 122mm symmetrical Shimano cartridge bb, then judge whether that gives a proper centering of the chainrings within the spread of the freewheel stack in back.
I am near-certain that the 122mm will work, and the cartridge style bb won't care if your bb is 68 or 70mm.

You can sight rearward along the sides of clean chainrings once you get a known bottom bracket in place. I would not bother fussing with cup/cone spindles unless as I do you perhaps have an assortment of them at hand. The Shimano cartridges are inexpensive and trouble-free.

royale81 02-29-16 12:48 AM

thanks people.
I'll remeasure the shell but I'm pretty sure it reads > 69mm. But that's what got me feeling like I couldn't believe my eyes.
As for the spindle, the B measurement must correspond in some way to the combination of the shell, cup and bearing widths - if the spindle is too long by a few mm, the adjustable cup might still allow a fit, but if the spindle is too short (B measurement) the bearings won't sit on the spindle races AND the cup races.

The crankset is made by Sugino - and from what I've read, in the old days, some Japanese models were ISO, with JIS introduced in the mid-80s or so. Hard to tell.

In any case, thanks for all the input. If someone owns an 81 Royale with the original BB spindle, I'd love to know it's markings/measurements. Thanks!


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