Hello,

I am in the process of turning a recently acquired PX10 into a single speed and need some help sizing the BB spindle.

PX10 stock spindle length: 118.8mm

I just purchased:

Paul Comp 46T Crankset
- Chain offset: 44mm with 111mm ISO spindle

Paul Comp High Flange Rear Hub
- Center to Flange: 32.5mm
- Fixed Chainline: 44mm
- Freewheel Chainline: 48mm

I am looking at a Phil Wood Classic Stainless BB.

Would 120mm spindle length be a good length to order if I want to set the bike up for single speed?

Thanks!

Michael

What bottom bracket are you getting? In order to get a straight chainline, you'll want a 111mm axle.
Disregard the original bottom bracket axle length...that's the length needed for the previous crankset.

Only thing you need to worry about is chainstay/crank arm clearance.

Just find a 111mm ISO taper bottom bracket with whatever the correct threading you have in your bottom bracket shell.

The spindle length always depends on the crankset being used, not the frame. If the Paul crank calls for a 111mm ISO spindle, that's what you should use.

If you really want a Phil BB, you should use a 110mm ISO (as they don't make 111mm).

You'd be .5mm off. That's .5mm from "perfection". A mm is pretty small. I'm thinking it will be satisfactory. Just be careful and wear a helmet in case the bike explodes.

Will you EVER ride it fixed> If yes, I'd get a 115 which would still give you a silent and safe chainline.

I typed the same thing until I re-read his post. Had to start over.

Meh. Whatever.

I'm going to get a sandwich.

Ok so 115mm would give me the ability to change it from Freewheel to Fixed but 120mm would be the best sizing for Freewheel only?

Thanks!

Michael

You are aware that the BB in that frame has French threading, right ?

It's Friday. Treat yourself to a deluxe burrito.

Yessir! Thanks!

HAHAH!

Just trying to avoid spending extra cash (beyond that I'm already sinking...) on my first build and nail down the best sizing/tolerancing as any Aerospace Engineer should...

Plus... When I was I kid, I had sweet little Hutch BMX that had an incorrect spindle length from day one. I never changed it out and it had the slightest of "clinks" on the chain stay. I'd prefer to avoid that utterly horrendous characteristic again.

are french threaded phil cups a thing of the past now?

As of this year, yes. They may still have a few left in stock though.

I just send them a Sales request email. If a Phil Wood BB isn't available is my only other option Velo Orange?

Velo Orange doesn't make ISO taper bottom brackets.

Ok, Velo Orange does only JIS. I think it should fit the Paul Comp ISO crank I have...
I just need to discount the 115mm by 4mm and I'm back to their 110mm or 113mm option.

https://support.velo-orange.com/#bbarticle.html
It's usually possible to fit an ISO crank on a JIS BB. The only caveat is that the crank will be 3-4mm wider than if an ISO BB was used, so pick a slightly narrower spindle and tighten the crank bolts securely.

It feels like I'm heading down a bit of a rabbit hole by not asking the question I'm actually wanting to know the answer to. HAH!

How much chain offset between front gear and back gear is acceptable for a quiet ride?

Here:
Phil Wood Crankbearing Mounting Rings French Alloy Bottom Bracket Cups | eBay

Rivendell shows them as in stock as well.

You could also send the crank back and get one meant for a JIS spindle...

He could also just throw the bike in the trash cause french bikes are the worst.

Is there something wrong with the original equipment Stronglight cups, I wonder? In a pinch, you could just turn the original spindle around to mount the drive side arm on the short end of the original spindle and get a pretty decent chainline:



Otherwise, I've successfully substituted Campagnolo and Sugino spindles into Stronglight bottom brackets.

Finally, Velo-Orange sells a metric thread bottom bracket cartridge in a variety of widths:

Grand Cru Bottom Bracket, French Thread

This!

Funny... I'm told that's where it was found.