TA Zephyr Triple BB what spindle length?

[randynewmanscat]

The longest BB axle I can lay a hand to is a 68/117mm Shimano Deore loose balls.
It's too short, probably by 2mm. I thought it would be close but the 29T inner ring kissed the chainstay before the wrench would have clicked.
It's JIS both parts and the taper was in no danger of running out, it looks right.
If you have or had a Zephyr triple
what length axle did you use?
For an added complication the Shimano spindle is asymmetrical, it is 1.5mm longer on the RHS so 118.5 if it was a contemporary piece.

 

[Ajax Bay]

Check how far the FD will reach out beyond the large ring. That gives you an idea of how many mm you have to play with. I'd go 122mm UN-300 or Stronglight similar BB. That'll give you the extra 2mm you need to keep the inner ring clear of the chain stay. Another option to consider is swap to a 28t or 27t inner which similarly may clear the chainstay. Every tooth less is 1/xx less radius (so 64mm for a 29t goes to <62mm for a 28t (all measurements inaccurate)).

 

[randynewmanscat]

I emailed Spécialités TA on the weekend and they replied this morning.
They said 116mm which sounds unlikely. I am going to call on my LBS who are a TA reseller and see what they have to say about what TA said.
The last chainset fitted was a Deore XT 700 and 30T just cleared the chainstay with the same 117mm spindle and the chain line was appropriate for all the most used F&R sprocket positions.

 

[Ajax Bay]

The chainline you should aim to hit is middle ring in line with middle sprocket (or between the middle two if even number of sprockets). This will ensure your more nuanced "appropriate for all the most used F&R sprocket positions" is satisfied.
Clearly if 118.5mm symmetrical is too short, you've got a 'not less than' answer in practical terms. Does it matter what your LBS says? What will you do if they say 'yes, 116mm'?

 

[randynewmanscat]

The chainline you should aim to hit is middle ring in line with middle sprocket (or between the middle two if even number of sprockets). This will ensure your more nuanced "appropriate for all the most used F&R sprocket positions" is satisfied.
Clearly if 118.5mm symmetrical is too short, you've got a 'not less than' answer in practical terms. Does it matter what your LBS says? What will you do if they say 'yes, 116mm'?

They can demonstrate to me in the shop by offering up the drive side partially torqued to their offering and I'll measure it. If its right they get my business.
I won't be leaving it with them, the frame was re enamelled a few years ago and is pristine, I don't want to have to berate them.
I'm not the only one to get a random reply from TA, if they weren't 4 hours drive away I would show up and say show me your 116mm spindle being the correct length for clearing this 29T ring.