Omni Racer Bottom Brackets

[David Hays]

Has anyone here tried Omni Racer bottom brackets like these? 

https://www.omniracer.com/product-page/race-lite-titanium-ceramic-jis-square-taper-bottom-bracket

Any feedback? 

Thanks.

David Hays

Buffalo, New York

USA

[Brad]

Is a 2 degree taper JIS?  ISO?  Both?

[Arrick Underhill]

I haven't tried the ceramic ones, but I have the regular ti ones on three bikes. The bearings are smooth and they run forever. 

/Arrick in Philly

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[David Hays]

Thanks Arrick.

The choices are overwhelming. Which are you running:

the Cromo Steel JIS 2.0° Square Taper Bottom Bracket

the Cromo Steel Ti Ceramic JIS 2.0° Square Taper Bottom Bracket

the RACE-Lite Titanium JIS 2.0° Square Taper Bottom Bracket

or

The RACE-Lite Titanium Ti Ceramic JIS 2.0° Square Taper Bottom Bracket

Thanks.

David

In Buffalo

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[Benz Ouyang]

I thought both JIS and ISO have 2° tapers, except ISO has a smaller end than JIS?

[Peter Adler]

benzouyang's got it in a nutshell. The late great Sheldon Brown has a whole thing on this issue:

https://www.sheldonbrown.com/bbtaper.html

A 2° angle on each face (4° total) is universal, but different standards cut off the tapered rod in different places. An ISO spindle tapers down to a smaller square than a JIS spindle, so an ISO crank fitted on a JIS spindle will sit about 4mm further outboard than it will on an ISO spindle of the same length. And vice versa.

There are other "spindle tapers" (misnamed, because the taper angle is the same 2°  for all of them; the cutoff is just at different points on the slope down to the intersection). Pre-CPSC Campagnolo (1978) has a cutoff point/square bigger than ISO, but smaller than JIS. From the C-Record era onwards, you often see references to "old taper" and "new taper" (really ISO), with the more expensive Record/Croce d'Aune and Chorus cranks using the new ISO taper, and the cheaper cranks using the traditional taper. This is important when you're trying to swap in a later sealed bearing Campy BB to replace an old loose-ball BB. For the most part, you can fudge old Campy cranks on both JIS and ISO.

Then there's Ofmega/Avocet spindles, that taper down smaller than everybody else's; Ofmega/Avocet cranks/spindles fit each other, but every other crank will bottom out on an O/A spindle, and a O/A crank won't get far enough onto an ISO or JIS spindle for secure contact.

At one point, I had drawn up an infographic for all this nonsense for another forum, but I can't find it at the moment

You can do a lot of chainline fine tuning with taper mismatches, if you can keep the correction formulas straight in your head. For years I've run French triple cranks (Stronglight/TA/Nervar, all ISO) on a 119mm Phil Wood JIS bottom bracket, which converts to 123/123.5mm ISO, roughly what the crank manufacturers recommend.

Fortunately for those of us who sometimes have trouble remembering what the taper mismatch does in each configuration, Omni Racer does both JIS and ISO bottom brackets in common lengths, in pretty much every combination of steel/titanium spindle and steel/ceramic bearings.

Peter "involuntary spindle mismatches are how I build almost everything" Adler

Berkeley, CA/USA

On Saturday, June 12, 2021 at 9:36:53 AM UTC-7 Brad wrote:

[r3aw...@gmail.com]

I have one running on my Rawland. It has been fantastic so far.

I actually have a brand new one (installed but never used) that I can sell if anyone needs. I am pretty sure its a 113mm but can check.

Only thing is some small marks on the NDS cup from installing but nothing bad. 

[Evan Estern]

I had one on my Norther Lyon.  The 110 mm spindle size left about 1.5 mm of clearance between the chain stay and the chain ring bolts on my White VBC crank set.  The 110 mm SKF I replaced it with had about 3mm clearance in the same spot.  It always ran smoothly but when I pulled it after a few thousand miles it looked like water was getting past the seals on the bearings.

[Evan Estern]

Correction, I had the version with conventional steel bearings.