Norta Crank: Which BB?

[Dries]

Hi all,

Hope someone can help me out because I can't continue restoring my bike until I know which BB I need
I recently bought a new (old type) Norta crankset which will look good on the Minerva-frame. The problem is I don't know what size bottom bracket I need to buy for this crank. Sheldon's site doesn't list Norta, nor SR crank-BB combinations. Is there any way to measure what size BB I need beside the 68mm english thread (square)?

A big thanks in advance!

Pictures of the crank:
https://dl.dropboxusercontent.com/u/237 ... .48.32.jpg
https://dl.dropboxusercontent.com/u/237 ... .48.52.jpg
https://dl.dropboxusercontent.com/u/237 ... .48.52.jpg

 

[lewisfoto]

Re:

Are you asking what spindle length or which threading?

The taper for a SR should be JIS, no problem there. If your bottom bracket is 68mm then most likely you want English threads. Spindle length?? don't know, what is the rear spacing and how many speeds?

 

[Dries]

Re:

Hi lewisphoto, thanks for quick reply. It's an English thread 68 mm, that I know.
The frame spacing is 126 mm but might be spread to 130 mm because I would like to have this 8-speed (unless that is possible without spreading?): https://www.sram.com/sram/road/products/pg-850-cassette
I thought the spindle length depends on the cranks used.

Would someone mind explaining me how the the spindle length relates to the number of speeds, rear spacing, cranks, etc. because I can't find that info anywhere...

One can just measure the spindle length by mounting the rear wheel and cassette on the bike? If so pretty please tell me how? Or am I missing out on something now?

 

[lewisfoto]

The Idea, of course, is the spindle must be long enough that the big ring clears the right chainstay but still manages to keep the rings close to the center of the freewheel (cassette) for optimum chainline. Right, so as you noted many manufacturers publish spindle length recommendations, but not if you have an older or off brand chainset. Because the SR chainset is JIS I would start with the numbers for square taper Shimano road double set ups. It may take a little bit of trial and error which an old bike friendly bike shop may be able to assist with.

 

[Dries]

That's a clear answer. Thanks again and I'll have a look right away.

 

[Dries]

if I may ask one more question about this subject:
Looking at the new crank and the old (Dura Ace), one can clearly see the width is different. Still need to measure the exact size.

Left is the new one, right is the old Dura Ace

The old Dura Ace crank was used with a 6 speed cassette. The new Norta crank will be used with an 8 speed cassette. Following your advice on looking at older Shimano spindle lengths it's not clear to me whether I need a 112/113 mm spindle length or something else... If you wouldn't mind helping me one more time, I'd be really pleased.
Sheldon lists the following:

thanks in advance.

 

[Midlife]

Silly question but why not use the Dura Ace Crankset? Often it's a case of trial and error with these things, have you got a standard UK 112 mm Dura ace axle to try?

Shaun

 

[Dries]

Hi Shaun,

Not really a silly question because I would love to reuse the Dura Ace crank but the thread inside the old crank is gone and when I went to my local bike shop, they hammered it of the spindle. Resulting in an unusable crank.

I think I have the old 112mm axle laying around. I'll have a try on mounting it back on the frame as a reference.
Thanks!