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I may have messed up....Avocet cranks????

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I may have messed up....Avocet cranks????

Old 01-22-20, 07:53 PM
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I may have messed up....Avocet cranks????

Hey guys and gals,

I purchased an Avocet crankset for my Jack Taylor. It's a triple crankset. Like an idiot I didnt do my homework and learned that it has a unique spindle. I found one for a double but not a triple...Any thoughts? Does anyone have any experience putting an ofmega or Avocet crank on a campy or Shimano tapered BB? It seems to work on both Campy and Japanese sized spindles but Sheldon says its unique.. Any thoughts?

Thanks

J.J.
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Old 01-22-20, 08:14 PM
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No, not all of them are "unique", some are but many sold in the US were compatible with Campy spindles and other Campy knock-off brand spindles. However, with a Shimano JIS spindle you may experience 'class B' or lower fit...try one and see! If it fits without bottoming out or too-little interface contact then...you're good to go in my book.And if you have the option try a Phil Wood BB, those used a "hybrid" spindle taper that might be right in the sweet spot!
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Old 01-22-20, 08:18 PM
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Originally Posted by unworthy1 View Post
No, not all of them are "unique", some are but many sold in the US were compatible with Campy spindles and other Campy knock-off brand spindles. However, with a Shimano JIS spindle you may experience 'class B' or lower fit...try one and see! If it fits without bottoming out or too-little interface contact then...you're good to go in my book.
Thanks for the input. I put it on a Philwood BB and it goes on, it tightens and seems to work. Very far from bottoming out. The campy one seems to fit like a glove but my 120mm spindle is 1-2mm short. Thinking about putting the campy on with a spacer under the fixed cup.
I'm having some bad luck. My philwood works, spacing is ok but there is a little freeplay in the BB..from side to side. Maybe that is common for Phil because my Phil hubs are the same way LOL>

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Old 01-22-20, 09:46 PM
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My experience with Phil bottom brackets is they do not have the free play the hubs do.
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Old 01-22-20, 10:00 PM
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Originally Posted by repechage View Post
My experience with Phil bottom brackets is they do not have the free play the hubs do.
That's my experience too. FWIW Phil will rebuild a BB with new bearings for 30 bucks or so, IIRC.

All of the Avocet cranks I've dealt with fit campy and campy copy spindles of the same era just fine. The skinny ones must have just been the first year or something.
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Old 01-22-20, 10:42 PM
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OP mentioned Ofmega. Might the Avocet crank had been made by Ofmega? If that's the case, Ofmegas do have a slightly different spindle taper than most other Euro ISO cranks. IIRC, the Ofmega spindles have a longer taper than most.
I remember dealing with this with my Ofmega Mistral crankset a few years ago.

Last edited by Chombi1; 01-23-20 at 02:15 AM.
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Old 01-22-20, 11:51 PM
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...
...Ofmega did make the Avocet cranks. There are, indeed, two variations. The ones with the unique spindles are quite distinctive, and considerably smaller in dimensions of the square taper and crank socket. There's no mistaking when you have one, because the cranks just won't fit onto a regular spindle. After a certain date ( which I have either forgotten or never knew), Ofmega went to a standard size socket and spindle.

I have at least one of the Avocet triples here. The smallest ring is mounted on holes that are drilled and tapped into the spider arms. I imagine a lot of them have broken by now, because this seems to be asking those aluminum spider arms to do an awful lot considering the amount of material in their cross section. I don't recall what it took in terms of spindle length, but I decided to run it without the smallest ring anyway. I just used the spindle that came with it on the bicycle it was on.
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Old 01-23-20, 10:03 AM
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Originally Posted by 3alarmer View Post
I have at least one of the Avocet triples here. The smallest ring is mounted on holes that are drilled and tapped into the spider arms. I imagine a lot of them have broken by now, because this seems to be asking those aluminum spider arms to do an awful lot considering the amount of material in their cross section. I don't recall what it took in terms of spindle length, but I decided to run it without the smallest ring anyway. I just used the spindle that came with it on the bicycle it was on.
I have an Avocet triple I used on my wife's bike. It held up fine for many years, but she doesn't punish her equipment.

The spindle measures 124mm end to end, and has an ISO taper.

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Old 01-23-20, 11:18 AM
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here is what sheldon has to say about this subject https://www.sheldonbrown.com/bbtaper.html

If this a relatively new avocet/ofmega it is probably ISO standard....mine was

(part of the fun is that "older" ofmega is not well defined, per sheldon "Note: Old Ofmega/Avocet spindles were quite a bit skinnier/longer even than ISO. There are no modern bottom brackets that work with old Ofmega/Avocet cranks.)

and per sheldon on JIS/ISO interchangebility


If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length.ISO crank on J.I.S. spindle -- small square-taper hole in crank
places it farther outboard on the spindle.




Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.

Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles.

In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.

Taper matching was fairly important back in the day of loose-ball cup-and-cone bottom brackets, because these required regular maintenance/overhauls, and this required removal of the cranks. Every time you remove and re-install a square-taper crank, the hole in the crank is liable to get very slightly larger.

This was particularly an issue when using J.I.S. cranks on ISO spindles, because over time, as the crank went on farther and farther, you could run out of taper, and the square end of the spindle would become flush with the surface the crank fixing bolt/washer pushed against. At that point, further tightening of the bolt won't make the crank any tighter, since the bolt is bumping onto the end of the spindle.

Tolerances on older spindles may not be closely held, and dimensions may vary enough even with the same model number to affect crank/spindle compatibility.

The if end of a bolt-type (hollow, internally-threaded) spindle is too small, it may be ground down, as long as the spindle does not bottom out on the back of the crank and the spindle's internal threads are long enough to hold the bolt.

These days, however, most folks are using sealed cartridge bearing bottom brackets. With these, there is no routine maintenance required, so typically the crank will be installed once, and will stay in place unless/until the bottom bracket needs to be replaced. This greatly reduces problems of wear to the interface.

I generally avoid mixing sizes on customers' bikes, but I have a lot of experience mixing ISO/J.I.S. in both directions on my own personal bikes, and it has never given me a lick of trouble.

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Old 01-23-20, 05:56 PM
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Originally Posted by squirtdad View Post
(part of the fun is that "older" ofmega is not well defined, per sheldon "[color=#000000]Note: Old Ofmega/Avocet spindles were quite a bit skinnier/longer even than ISO. There are no modern bottom brackets that work with old Ofmega/Avocet cranks.)
Sutherland's has a graphic representation of spindle tapers, including the old style Ofmega:


Source: Sutherland's 4th Edition
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Old 01-23-20, 08:10 PM
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Thanks for all the input guys!

Thanks
JJ
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Old 01-23-20, 08:16 PM
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Originally Posted by squirtdad View Post
...per sheldon on JIS/ISO interchangebility

If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length.ISO crank on J.I.S. spindle -- small square-taper hole in crank
places it farther outboard on the spindle.


Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length...
Note that the above oft-quoted statements reflect a mathematical error.
The quoted 4.5mm is the COMBINED offset difference of the left arm plus the right arm. So each arm sits outward or inward only 2-2.5mm versus the other (JIS or ISO) taper.

The math error surely resulted merely from a failure to distinguish taper angle (2-degrees) from the included taper angle (4-degrees).
It's an easy mistake to make when doing these sort of trig calculations.

It is always easy and perhaps a good idea to do one's own comparative measurements of spindle tapers, either by measuring the taper width at some standard distance (the thickness of the caliper's jaws) from the end of the spindle, or by comparing the distance from the end of each spindle that a fixed-setting caliper slides up the taper. Better yet, do both!
Spindle width measurement at 1/8" from spindle end:

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Old 01-23-20, 09:01 PM
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I have one of those Avocet triples- it's a beautiful crankset. I've heard stories that they're supposed to be one of the lightest cranksets around- I just think it's pretty.

As far as the spindle goes- I bought it with the matching Avocet spindle.

FWIW- the Avocet spindle box had measurements on it.



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