# What is the *Best* way to put an Ultegra crank on a BB30 Specialized frame?



## TiCoyote (Jun 28, 2005)

I ride a Tarmac Expert with 6700 components and an FSA crankset. 

I've been seeing good deals on Ultegra 6800 groupsets, and I'm thinking about making the switch. Here's my question, what is the best way to attach the cranks to the frame? By best, I mean something that is going to ride and feel natural, have great power transfer, won't fall apart, be quiet, be reliable, etc.

Here are some options I've seen: 
Wheels Mfg Adapter: Wheels Manufacturing Universal BB30/PF30 To Shimano Adapter

Wheels Mfg Bottom Bracket: Wheels Mfg BB30 to Outboard Bottom Bracket for 24mm Cranks (Shimano)

Praxis Conversion Bottom Bracket: CONV BB - SHIMANO - Praxis Cycles


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## MMsRepBike (Apr 1, 2014)

Our shop uses the Praxis bottom brackets, they work great. Shimano suggested for us to use them a while back so we did.


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## tlg (May 11, 2011)

Adapter cups suck. The shimano crank doesn't have enough side preload to keep them tight. Go with an adapter BB. There's this model too, it's what I switched to.
KCNC/RWC BB30 to HT2 BB Adapter


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## TiCoyote (Jun 28, 2005)

So why doesn't Shimano just make a BB30 conversion Bottom Bracket, or make a BB30 Bottom Bracket and a compatible crankset?


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## TheSame (Jun 29, 2014)

b/c shimano is always late to party with advancements in technology. They're leaving money on the table by not going to 30mm cranks. You rarely see their cranks on OEM builds since they don't make compatible cranks.


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## TiCoyote (Jun 28, 2005)

I ended up ordering a Wheels Mfg conversion BB with Angular contact bearings. It comes in red.


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## skinewmexico (Apr 19, 2010)

Praxis works great. Using it on my new Felt Fx5 build.


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## Special Eyes (Feb 2, 2011)

I would just use a BB30 crank. I avoid adapters when I can.


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## bikerjulio (Jan 19, 2010)

TiCoyote said:


> So why doesn't Shimano just make a BB30 conversion Bottom Bracket, or make a BB30 Bottom Bracket and a compatible crankset?


BB30 as a standard was invented by Cannondale and put out as an "open" standard around the year 2000.

What does it say to you that in the 15 years since then that neither Shimano or Campagnolo ever made a BB30 crankset (and Overtorque is not BB30, it's BB386).

Is it:

a) because of the not invented here syndrome?

or 

b) BB30 was an inherently crappy piece of engineering?


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## masont (Feb 6, 2010)

Special Eyes said:


> I would just use a BB30 crank. I avoid adapters when I can.


The Praxis BB is not an adapter. It's a BB. And it is the right answer to this question.


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## tlg (May 11, 2011)

masont said:


> The Praxis BB is not an adapter. It's a BB.


It's converting (adapting) a BB30 to a 24mm BB.
It's just semantics. Praxis says it's "Not an adapter, it's a conversion BB". 
KCNC's BB does the same thing, and they call theirs an adapter. 

convert
v.verb
To change (something) from one use, function, or purpose to another; adapt to a new or different purpose.



> And it is the right answer to this question.


Absolutely. A threaded BB is needed. The problem with using a shimano crank on a BB30 is that the shimano design has minimal side thrust to hold the bearings in place. The tightening force of the end cap is a miniscule 0.7 - 1.5 Nm. If I make it finger tight, it's over tightened.


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