bark_eater 

I'm looking for a 68mm cartridge bottom bracket to fit a Avocet triple crank set to a 126mm spaced bike. The previous franken bike it came off had a 121.5 Shimano BB and the engagement on the JIS spindle was a bit shallow. It was also being run as a double. Its new home is a bit of a basket case, and the bottom bracket threads are a little loose after being cross threaded and chased, so I realy want to go with an ISO cartridge Bottom Bracket. There's so much other stuff going on with this bike I cant see spending the money on a Phil Wood. Any other suggestions? I'm also looking for bolts and spacers to reinstall the granny ring, if any one has a source for those parts. Thanks.

Bianchigirll 

I assume you looked at Velobase and Sheldon Brown's pages to get the skinny on the correct lenght and offset?

I believe Avoet used a unique taperand any JI(S or ISO spindle may be a makeshift fit.

bark_eater 

Anecdotal references put the original spindle leangth at 124mm. Longest ISO cartridge BB I've found so far are 115mm.

JohnDThompson 

The OEM Avocet triple spindle measures 124mm overall.

Only very early Avocet cranks used the proprietary Ofmega taper. They're pretty rare. If the OP's crank fit on the Shimano cartridge, it's probabl;y not one of the very early ones.

Salamandrine 

Looks like a 119 is what you need, unless your Avocet is one of the ones with a weird taper. Unlikely since it kind of sort of fit on JIS apparently. How was the chainline with the 121 JIS? Was there room for the small chainring? Good idea to test fit to ISO before buying anything if you can. Vintage Campy taper was close to ISO but not the same thing exactly. There aren't always easy answers when it comes to BB compatibility. These below would have all been asymmetrical spindles.




Interesting that the weird taper ones are claimed to be the non USA models. I always thought the non USA ones were all marked Ofmega.

Moe Zhoost

Avocet cranks were made by Ofmega, whose spindles had a smaller taper end. I've heard that they work with Campy spindles, but they may not fit far onto a JIS spindle. Good luck.

bark_eater 

Do you have a diagram to go with the numbers? What are values A, B and C? I'm wondering if I can get enough drive side extension with a 2 mm shim on a 115mm Campy bottom bracket. I didn't ride the original bike the crank was on. I bought it off a guy because "the gears don't work" and promptly took it apart. It was also missing the inner ring.

jeirvine 

I have looked for a while and come up empty. Stronglight sells triple bolts that appear similar, but the head is too small (so learn from my mistake, and don't order those from France!) I've heard of people making DIY sets for Campy triples. I just picked these up and will attempt to modify them to work:
https://www.amazon.com/gp/product/B07QG96JBS/

bark_eater 

There was another set of bolts and spacers that was supposed to work. I think it was a Campagnolo product, also obscure. I didn't book mark/ take notes of the the reference.

3speedslow

All this sure makes me want to hold on tight to my Triple Avocet crankset with matching BB! Don’t want to have to fudge with it, just want it to work.

gLWTSearch!

Salamandrine 

If that's a measured length, I'd trust that over what it says in Sutherlands 10 or 15 years after the fact.

bark-eater, I probably have a diagram somewhere, but A is the distance from the bearing race to the NDS end, B is the distance between the bearing races, and C is the distance from the drive side bearing race to the end of the spindle.

Avocet were compatible with Campy WRT chainring bolts and stuff. The early Sugino mighty was also interchangeable.

WGB 

Sorry but I'm confused by this one.
Op had a 121.5 BB and "the engagement on the JIS spindle was abit shallow". Logically, shouldn't he need longer than 121.5mm to engage more??
JohnDThompson says Avocet triple spindle measures 124mm
Salamandrine says 119mm unless one with weird taper.
Posted Sutherlands chart shows triples at both 119 (USA) and 124.5. Unsure why 124.5mm exists. Was it a European only length?
Not saying anyone wrong. Just saying I'm not keeping up....

Salamandrine 

I'm not saying I'm right either. Just presenting info that is out there. The OP is going to have to figure this out.

Mixing and matching bottom brackets and cranks was always a dark art, even BITD when this stuff was new. In a shop, it wasn't that big of a deal because you could try and fit for taper and length, after consulting Sutherlands. If you don't have a bike shop with drawers full of BB's and spindles, it's going to be a PITA.

People most often bought a new crankset as a complete set along with a matching BB, for good reason.

dddd

You would get MORE engagement if the taper were smaller, but then the spindle length would need to be about 2 or 2.5mm LONGER on each end to maintain the same chainline as with a JIS bottom bracket of any existing length.
This doesn't take into account the offset of the original spindle. A modern cartridge bottom bracket often will have no offset at all (i.e. symmetric about the bottom bracket shell).

I often get away with choosing a much shorter chainline, which suits my choice of gear selection out on the road (i.e. staying mostly in the big ring).
But the limitations of an "inward" chainline shift can be 1) chainring clearance, and 2) the possibility that the front derailer may not retract with enough authority to force a downshift.

A recent example of how all of this works out on my bike is my use of a 107mm JIS symmetrical bottom bracket with a Sugino Mighty Tour crankset on my 2X6 speed Centurion Pro-Tour. I also considered using a symmetrical 111mm ISO bottom bracket since the taper match is much better structurally, but I cheaped out and used what I had. My resulting "chainline" measurement (out to between the two chainrings) is probably just 40mm, yet the chainrings have clearance, the front derailer works perfectly and the chainline is very much how I like it. BTW my rear spacing is 125mm at this point.

Moe Zhoost

C=Drive side

3speedslow

I might be able to check my BB spindle length if I am able to sneak past the dragon guarding my horde. LMK if any interest.

The Golden Boy 

No idea, but here's mine:


1986 Trek 400 Elance by Dave The Golden Boy, on Flickr

verktyg 

As esteemed BF member JohnDThompson pointed out there were 2 generations of Avocet cranks and BBs.

I suggest that you post a picture of your crank rather than having us guess which one you have....

Going way back to the first edition of Sutherland's, the listed specs have always needed to be verified: "If that's a measured length, I'd trust that over what it says in Sutherlands 10 or 15 years after the fact."

Sutherland's - 125.5mm... Measured Length - 124mm.... ???

The numbers on this Avocet BB spindle box show that a # 3 "axle" is the correct one for the later cranks.



BTW, I've used Shimano BB cartridges with lots of different cranks. If it fits, it works!

Aluminum is very malleable. ISO and JIS specs are only relative to new or slightly used cranks.

Once a crank has been mounted and torqued down, the aluminum stretches and there goes all of your holy/sacred published specs!

I put this Flickr album together one night about 10 years ago when I was trying to assemble a SS beater. I need to update it but I haven't been able to log into Flickr...

https://www.flickr.com/photos/282672...57627678462359

Scroll down and read my notes under the pictures.

verktyg

unworthy1

IIRC (and if you actually need this option) Miche made a sealed BB unit with ISO taper spindle (might be the "Primato" or the "Team" model), and when you could find it there is a 122mm spindle length. But shop carefully because I think Miche has started offering JIS taper spindles, too, so read the fine print. These were moderately priced units, BITD.

JohnDThompson 

Yes, 124mm is a measured length.

The mounting bolts for the 74mm BCD ring were interchangeable with the Campagnolo Record triple inner ring bolts and stand-offs. I'm not aware of a Sugino crank that used similar bolts and stand-offs for mounting a triple ring.

bark_eater 

Here's what I'm working with. The Shimano JIS spindle stopped 6mm from the "top".

Salamandrine 

Most did not; that is true. I think that there was a 70s era mighty tour triple that used long bolts and spacers. I remember them from somewhere/something. At any rate there are these NOS triple chainring bolts and spacers on ebay. There seem to be other triple length chainring bolts available as well.

https://www.ebay.com/itm/NOS-Sugino-...-/291540049880

Thanks for the confirmation on spindle length. Might be tough to find a modern cartridge BB that fits, even assuming ISO is a reasonable fit. Vintage traditional BB is another option.

I should add that I have no idea if the above bolts are long enough for an Avocet triple. Maybe. Might need some improvised spacers.

JohnDThompson 

Those bolts differ from the Avocet and Campagnolo bolts in that they are used to mount three rings using the same BCD, with a spacer between the inner and middle rings. The Avocet and Campagnolo triples used bolts with a separate BCD (74mm and 102mm for Avocet; 100mm for Campagnolo) that threaded directly into the crank spider, with a stand-off piece to hold the ring at the proper seperation from the middle ring. The Sugino AT crank also used separate BCDs (110mm for the outer rings; 74mm for the inner ring), but the inner ring clearance was an integral part of the crank spider, not a separate stand-off piece.

A moot concern, because they won't work with the Avocet crank, which uses a long, "male"-threaded bolt and stand-off rather than the simple spacer, and are the wrong thread for the mounting holes in the Avocet crank. You can see the bolts and stand-offs in the picture I supplied previously.

bark_eater 

The Campy bolts are on Ebay for $40. I wont worry about those till I can find a suitable bottom bracket.

jeirvine 

Link? I haven't seen them for under $90.
-J