Yet another BB Query. For the 74(?) Moto Champion Team(?). I'm riddling over the spindle length. This afternoon I will head over to the LBS to look for either a spindle or a French-thread UN55. Maybe I'll get some help here before I go.

68mm French BB. 5-speed FW. The plan is to use Nervar 631 (I think) crank arms paired to TA rings. The original crank may have been Campy Record, but that's a guess. So what length?

VerloBase has 4 Nerver 631-like entries; only one lists spindle length, 117mm.

As an experiment I've tried some BB cups and spindles from my stash. The only spindle I have that works is a Stronglight 120mm matching the Competition ref65 entry in VeloBase, marked "Marque Déposée". It misses the chainline by at least a cm too long on the right. Some of that miss might be due to length and some might be due to the taper.

The only other spindle I have is marked 3E (not 3N - I misremembered) but its bearing-bearing distance (measurement B) is too short for the cups I have. Sutherland's does say that the Stronglight B value is larger than normal, and perhaps I'm using Stronglight cups, which might explain why the other spindle doesn't work.

The only other data points from Sutherland's are cryptic length values for Nervar as 120 or 120.5mm.

Given that the chainrings are small (47-34) they have no problem with stay clearance. So I'm tempted to try a 115mm UN55. But this is all so fuzzy. Have any of you ever matched a UN54/UN55 to Nervar 50./4 arms? Any input would be appreciated.

Thanks!

No I haven't but I'll speculate...the taper on any Shimano spindle will be JIS...the taper on any vintage Stronglight (and Nervar) will be ISO. My understanding is that IF the ISO crank doesn't bottom out on the JIS taper, it WILL be father out from the centerline (by some say 4.5 MMs)
My Sutherland's says a Nervar double will be either 117 or 121 so I think the experimental length could be 112.5 to 116.5 depending on your model crank, and as always...YRMV.

Thanks, un-w. 110 was the only appropriate option they had, and it looks to be fine. There's plenty of stay clearance, and the crank moved inboard some reasonable amount.

Are you looking for a Shimano UN 55 with French (righty-tighty) thread? I didn't think this existed... ??

I do know that when I put a Stronglight crank on a new VO French BB, I suddenly discovered that it didn't go in as far as it did on the previous spindle (a Stronglight) .

Sheldon Brown explains this, but I have no idea how you would calculate it.

I believe I crossed my fingers and ordered a 117mm cartridge BB to replace a 122mm Stronglight spindle.

I went with a VO BB. As I understand it (and as unworthy1 suggested) putting an ISO crank on a JIS spindle can cause it to move 4 to 5mm to the right.

Most vintage French crank spindles (Stronglight and TA for sure) had a taper that was closer to modern JIS than to ISO. When this crank was made there were no ISO or JIS standards. Lots of real world examples of folks using modern JIS BB sets with vintage French cranks on this recent thread:

https://www.bikeforums.net/showthread...mpy-BB-spindle

It's threads like this that make me appreciate Phil bottom brackets...

I'm not sure what would be different with Phil (W?) except the price. I suppose you are suggesting that fitting would be easier because of some design feature.

One thing I've never understood about spindle dimensions is how to reconcile the left and right side lengths. You have three key dimensions (besides the taper). One is bearing to the right end, which dictates what Sutherland calls SER. Everything else depends on how the bearing seats against the fixed cup. The second key dimension is the distance to the other bearing, which can vary with how thick the cups are for a given shell width. (Of course this assumes you have the correct bearing size and the races match.) The third dimension is the length on the left. So when you use, for example, a nominal length of 110mm and a type of 3N, it tells you the inter-bearing distance (I think) but not how the remaining length is distributed L or R. I can imagine a spindle where the chainline is just fine and the lockring has just the right amount of threads, but the two pedals are noticeably different distances from the stays. The only way to know is to start trying things.

Once you get it close, you can adjust the cups back and forth to achieve equal offset side to side. Also, based on a recent thread in CR, it seems you can adjust the spindle offset, as it is simply pressed into the bearings and can move side to side. The extra degrees of freedom should make setup easier. That means (I think) that getting the spindle length correct/close is the primary (only?) consideration.

I think he meant because you can adjust Phil BB sets L or R to your heart's content to achieve the desired chainline/stay clearance. Just loosen one side and tighten the other to move the cartridge. Neither side is "fixed". Available with French threads. Pretty pricey, but maintenance-free and lasts forever. One of the few unimprovable bike parts.

I thought this thread was going to be about barbecue. I am disappointed. Shame on you for getting a man's hopes up, Jim.

+1. came here for motobacon.

With the pics you post in C&V Lunch you don't need any help!

Yep. This is what makes Phil BBs so nice. And not only do you have both L/R adjustable rings, but the spindle itself is only press-fit into the cartridge; there are no locating shoulders. Thus you can adjust your chainline beyond the +/- 5mm range that the rings allow by simple using a homemade press to offset the spindle in one direction or the other. However, this is also the one Achilles's heel of the Phil BB-- some have reported that their chainlines have spontaneously adjusted themselves! But in general, the Phil BBs are pretty great. That you can get rings for Italian, British or French BB shells makes them even better.

LOL! I also thought this was a BBQ thread.

and don't forget Swiss and Raleigh 26tpi, too.

bacon and Swiss...there ya go: it IS about a sandwich

to get into the murky weeds some more...and cranks spindles are VERY murky...Sutherlands likes to note the gross/subtle differences (NOT in taper, but in taper-end dimensions) between ISO, JIS, the "special JIS" of Dura-Ace, the "special ISO" of Campy, and then the real oddball Ofmega/Avocet. They note that Phil Wood made an attempt to split the diff and offered a compromise spindle that they called ISO but was in between the typical ISO and the Campy dimensions...and now they call it ISO/Campy.
It sure can get confusing, so don't try to outsmart the "system", just rely on trial, the old Go/No-Go...works every time.

I didn't know that you could move just the spindle too - pretty cool, but probably beyond my skill level to attempt. The only bad part with Phil is that I'm pretty sure you have to buy the French or other oddball rings separately these days. Drives the price up even further. Still reasonable though if you're looking for an install and never think about it again BB set.

This is true, if you buy new rings and a new BB it's expensive. But the most expensive Phil units (with Ti spindles) seem to lose a lot of value compared with the less expensive stainless versions, and can be picked up used on eBay for a lot less than you would expect (but they don't pop up too often). I picked up a Ti Phil for $60, barely used, and the seller included a set of alloy rings, which themselves cost over $40 new. The combo makes for an extremely light BB!

Nice score! Every once in a while you can still get an incredible deal like that on ebay. Hasn't happpened to me in a long time though, at least not with bike parts.