Stronglight 99

[NorwichVelo]

Has anyone got an idea of the bb requied for 68mm british bb shell with a Stronglight 99 crankset please?

[mjr]

Doesn't it depend what chainline you're wanting?

[gaz]

And whether you are running a single, double or triple on that chainset.

[The utility cyclist]

my nervar BB is 118mm for a double on a late 50s Carlton. I've used it with a Dura Ace 8 speed FD, a shimano 6207 and lately with the 1st Dura Ace model.

[NorwichVelo]

Its a double and ive found dome info suggesting JIS some ISO id be interested to hear from anyone who knows please

[Mick F]

I bought a Stonglight 99 double and Stronglight 651 bottom bracket back in 1986.
Still in use.

What the length of the 651BB is, I don't know.
Sorry, can't help unless I measure it with the chainset off.

[SimonCT]

Stronglight 99 on one of my bikes with 42/30.
I believe they were ISO taper.
According to the scribble in my notebook, it was fitted on 116mm Campag BB (ISO) for several years.
When that wore out I fitted a Shimano 115mm (JIS) which moved it out a mm or two.

[Brucey]

Its a double and ive found dome info suggesting JIS some ISO id be interested to hear from anyone who knows please

There may have been older variants of the 99 that were different (IIRC stronglight used to use a wide taper on most models into the 1970s) but most of the 99 model cranks that I have seen are ISO. So are the Model 80 and 100 cranks.

If in doubt, get yer verniers out. In simple terms (which BTW IDSTR having seen in print before... anyone?)

approximate taper dimensions in the crank socket are;

type---------ISO------------JIS
Outside---12.0mm-----12.3mm
Inside-----13.0mm-----13.3mm

Obviously the inside of a used crank may be worn larger and the outside may have a burr on it, so measure carefully.

If you measure a BB spindle, check

a) the nose dimension; if ~12.6mm or smaller it is ISO, if ~12.8mm it is probably JIS
b) on a used spindle, check the spindle width where the wear marks from the old crank end; if ~13.0mm assume an ISO crank has been fitted, if significantly larger then assume a JIS has been fitted.

If you have any doubts about your measurements or the accuracy of your verniers, get hold of some components that are known to be either JIS or ISO and compare. In point of fact if you do this you can even make a determination on a spindle using something as simple as an adjustable spanner.

Regarding spindle lengths, between crank wear on used cranks and variations in actual spindle dimensions it is usually a case of 'suck it and see' with any one brand. Also note that the shape of the flats on spindles varies somewhat. With used cranks if you fit a different type (brand) of spindle it may not fit nicely even if it is notionally of the correct type.

Note also that these cranksets would originally have been fitted with an asymmetric BB spindle whereas most (but not all) modern spindles are symmetric. Comparing lengths is made more difficult by this.

cheers

[NorwichVelo]

Cheers Brucey youre a font

Regards