The taper is the same for both JIS and ISO (2°), but the dimensions differ slightly such that the crank will mount on a different part of the tapered section. It won't ruin the crank unless it bottoms out on the taper or the axle extends past the crank:

http://www.os2.dhs.org/~john/crank-arm-seat.jpg

If it lands in the middle, as above, then go ahead and check the chainline.

Yeah, I know they have the same taper and will work if you don't gorilla torque the crank down, but I'd just rather not push it. There's time, it's not exactly great riding weather this time of year anyway.

Having read through this thread, I am puzzled by the bottom bracket length. I have always understood what is needed is a straight chainline. If you have a 120 OLD rear wheel, the chainline will probably be around 43mm. Then the distance from the center of the seatpost to the middle of the chainring would also be 43 mm. I would be surprised if a BB spindle greater than 107 mm would work. Stripped down as yours is I would think it would be around 22 lbs or less, hardly a porker. I think it is a very nice bike. BTW., the late great Sheldon said an ISO crank arm will work fine on a JIS spindle and I have found it so as well, although JIS on ISO spindle not so much.

Guess I've been lucky...put Campy Nouvo Record, Avocet and a 2010 Brompton (Stronglite?) cranks on JIS spindles without problems.

I happened to be driving by Performance Bike today and remembered that they are going out of business and everything was cheap. So I stopped in and found a Shimano UN-55 to test out for only $13. It doesn't specify JIS or ISO, so apparently it is one size fits all (that phrase always instills confidence in me). 113mm length. I don't really like how it feels when torquing the crank down, it just keeps going and going and you can't get a good feel for when enough is enough (I don't have a torque wrench in inch-pounds, either). It feels like I could keep tightening the thing down forever, and in my minds eye the ISO taper on my old crank is just getting smushed to oblivion... Eventually I did stop, removed the bolt to see what I expected, the spindle buried pretty far down and no where near bottoming out on the washer. So it doesn't look like it is tight (at least the fit doesn't look like my old JIS crank and JIS spindle did), and it doesn't feel like it is 100% tight either, but maybe it is, who knows.

Anyway, the 42t chain ring does have more room to the chain stay than my previous setup with a 40t did, but the chain line isn't great. I could use a few more mm's in spindle length to straighten it out. I was hoping to learn a little more from this trial but with the way the crank fit on the spindle I don't feel like I am any closer than I was. Any pearls of wisdom left out there? Thanks again.

Bb
 

the solid nut fixed on type was on least costly bikes , from Asia, so would be JIS...

a bit more up the price point and the cranks were held on to a hollow spindle with bolt and washer behind it

then came a bolt incorporating the flat washer and its hex socket used an 8mm 'allen' wrench to tighten it .. They work very well I'd go that way...



you can find a socket with an 8mm bit in it , to use a torque wrench to Know crank is on well , by the "how tight" numbers ...

Fwiw,
 

I don't recall if Sugino a company used to making JIS cranks used ISO to be like Campagnolo it was copying...


if so it would resemble drawing C in above posting..







....

Recent production Mighty Comp. Single (I believe Road, too) and the various versions of XD/RD2 are JIS...

And FWIW...Sugino continues to warn that their ISO taper is not compatible with anybody else's, at the risk of loss of warranty :twitchy:

Old thread but this may be of interest.

I put a nice, vintage Edco swiss made track crank on my Cannondale Capo. To test for spindle width I have some $ 30 bike shop specials I use to test with.

This set up needed a 118 mm to make it ridable but I was getting a close pass on my left crank arm, about 1.4 mm. I felt my chain line was good right where is was and did not want to go to 122 if I could avoid it.

On a friends advice I shucked out $90 for the Omni Racer Titanium 118 mm spindle BB, very light, (it saved just over 1/4 lb of weight ) and now (as my friend said it would)) the left crank arm rides 2.9 mm off the chainstay

Looking at the machining of the spindle it seems to ride a bit tighter and higher on the taper. Just to be sure I rode it 50 miles, tapped the crank arms in with a wooden block and hammer and retorqued the crank bolts, still the same clearance.

All good here now!

Considering the fact that "Loose Balls Rule" what about custom made titanium balls, cups, and spindle. Sure... Why not... If ya got the bucks...

Sometimes when I take a really good dump I wonder how much weight I am trimming off my next ride... sorry not to be rude.

You can really get carried away with the weight thing and manufacturers are perfectly willing to hipe the latest gram saving component.

Looks like you got the problem solved and by the way... NICE BIKE!!!!!

Like some of us on these forums..I'm coming off a relatively expensive pastime ( Ducati and BMW motorcycling addiction) so good bicycle parts look pretty affordable to me at this point,
, that may fade

The weight thing is another deal, I like light weight things just for the sake of being light. It may make no sense but much of what most of us do makes no sense.

Hey, I'm not talking about my Ducks without tossing out a picture , my 999 Mono in red. This is as good as it gets in Ducatiland (at least I think so), pulling onto the interstate on this thing gets the juices going.

https://cimg6.ibsrv.net/gimg/bikefor...206d152ea1.jpg

I rode my buddies 749S for one session at a track day and that bike handled like it was on rails. I've only had Japanese bikes. Last year I decided to find the one bike I always really wanted, a 1st Gen FZ1. Found one with less than 8K miles for $3000. Perfect old man sportbike and I like it more than any bike I've twisted the throttle on. My love for carbs returned, it's butter smooth from idle to redline. FI can be a pain in the ass and you need a $400 power commander to tune it. Still in the top 20 quickest street legal bikes 0-60. Going to have the wheels painted black the next time I need tires.

https://i.postimg.cc/wB9mbW7j/6000000004ffff.jpg

Nice bikes FZ Yamahas, I've never heard of any breakdowns and they still have the look and feel just right. If anyone thinks they know what fast is they may have a new definition of the word after an hour on that FZ. I love the little belly pan on yours, sets it off nicely.


Maybe we need a motorcycle thread! After all , two wheels is two wheels and , with the popularity of electrics, the self powered thing is changing.

As weird as this sounds, I paid more for my Trek Di2 Carbon Domane , used, than I did for my 999 Ducati. (It needed a few things but nothing big, just a little scary to dig into for the average owner)

You used to be able to buy that kind of thing off the shelf, e.g. Zeus 2000 titanium spindle, cups and mounting bolts, aluminum lockring and washers:

Great looking bike.