New Bottom Bracket for Power Meter

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#1
I am thinking about getting a crank based power meter (either Power2max or Quarq Riken).
Now I am trying to understand what other things need to be changed on my bike and I assume it will be the bottom bracket.

My current frame has a SM-BB91-41B bottom bracket and I am having Shimano Ultegra 6700 Cranks.

Questions:
- I assume BB91 is Shimano specific and I can only fit Shimano Cranks on it, right?
- Which other Bottom Brackets can be fit onto my frame?
 

theBlob

Bokeh master
Sep 28, 2011
2,863
1,450
129
...
#2
It took me a while to understand the variables in the equation

Your frame can either require a press fit BB or threaded GXP type BB there are also 2 types of threads Italian or English.
The difference is the thread pitch I believe.

The SRAM unit will not work with the shimano BBs due to the shaft length.
So you will need to get a SRAM specific BB this is where things are still a bit cloudy for me.
SRAM make two options cheap and ceramic but other aftermarket makers seemed to not exist.
I ended up getting a new ceramic bearing version from yahoo auction at less than half the price of the SRAM shop model.

I hope this helps.
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#3
It seems to be a three step puzzle:
1) Understand the frame standard.
2) Know which Bottom Bracket is/can be installed (maker)
3) Know which Crank (maker) can fit with the Bottom Bracket

My frame has a 86x42mm BB Shell and is pressfit - that would be the BB86 (or PF86) standard.
There are two BB versions from Shimano available for BB86 - the SM-BB91 and the SM-BB71 (!!!:confused:!!!) and they are of different price & quality.

Then I found the following compatibly information about which BB standard (frame) is supported by the different Cranks:
- Power2Max: http://power2max.de/support_kompatibilitaet.php?&lang=en
- Quarq: http://www.quarq.com/support/bottom-bracket

For Quarq/SRAM cranks is seems that they only fit with SRAM bottom brackets.
Power2Max support a wider range of Cranks and I read (maybe contradicting :(information) that the Rotor3D is compatible with Shimano BB's
- http://forums.cervelo.com/forums/p/9260/63974.aspx
No problems using shimano BB with rotor cranks. I was on 7900 cranks and tried the rotor 3d cranks and q rings with no problems.
- http://power2max.de/shop_details.php?artikelid=3
The ROTOR 3D is compatible with all conventional BB24 bottom brackets, for example by ROTOR or Shimano Hollowtech II.
- http://forum.tour-magazin.de/showthread.php?265779-Rotor-3D-Plus-kompatible-mit-BB86
http://www.rotorbike.com/nueva/infot...BBROAD_ENG.pdf
Du brauchst das Innenlager Pressfit 4130 von Rotor.
Any experiences, is Rotor compatible with Shimano BB?
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#4
Ok,

Forget Italian, BSA (Japanese) BB's as your frame will not take them - press fit is, press fit. You have no threading on your bottom bracket so no need to look at anything that is discribed as "Threaded (English/BSA and Italian)"

Now the Shimano SM-BB91-41B is BB90 standard (BB91 is the give away in the Shimano parts number) and there are plenty of 3rd party products out there for this standard, Token and KCNC Just to name a few.

According to Quark you have several options:


"Integrated Bottom Bracket - BB86 and BB90.

The integrated bottom bracket standard uses a 24mm spindle with press-in bearings. i.e. The bottom bracket bearings from an external cup system are pressed directly into the frame, eliminating the cups and threads. This system can use cranks designed for external, threaded bearing cups.

Variations on this system were developed independently at Scott, Trek and others. There is not a common name beyond "integrated bottom bracket" but the overall shell width is typically 86mm or 90mm wide so the terms BB86 and BB90 have been popularized.
Bikes with BB86 and BB90 include high end carbon models from Trek, Scott, Giant and others.

BB86/BB90 Compatible: Quarq ELSA 10R, Quarq RIKEN 10R, SRAM RED, SRAM S2275 MTB"
With Power2Max cranks they again have a pretty comprihensive table:


"Bottom bracket

BOR RR666: BSA68, ITA70, Cannondale BB30, PF30, Specialized BB30OS, Pressfit BB86, BBright
Lightning: BSA68, ITA70, Cannondale BB30, PF30, Specialized BB30OS, Pressfit BB86, BBright
ROTOR 3D: BSA68, ITA70, Pressfit BB86, BB90
ROTOR 3D Plus: BSA68, ITA70, Cannondale BB30, PF30, Pressfit BB86, BBright
SRAM S900 (GXP): BSA68, ITA70, Pressfit BB86, BB90
TA Vega and Carmina: BSA68, ITA70
tune Smart Foot: BSA68, ITA70, Cannondale BB30, PF30, Specialized BB30OS, Pressfit BB86, BBright
ROTOR 3D MTB: BSA73, BSA73 +E-Type, Pressfit BB92
ROTOR 3D Plus MTB: BSA73, BSA73 +E-Type, Cannondale BB30, PF30, Pressfit BB92

For BB86 and BB90 also applies: Because bearing seat and therefore the framework in the power2max sensor "dips", here are geometric relationships examined in order to prevent collisions and to ensure the mounting. The dipping area of the bracket should not exceed a diameter of 53 mm."
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#5
Just for the record the reason why they are marked as SM-BB91-41B and not SM-BB90 is because the bottom bracket design was first introduced to the MTB range and the SM-BB90 is the XTR version and has cups not press fit...... confused yet?
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#9
Now the Shimano SM-BB91-41B is BB90 standard (BB91 is the give away in the Shimano parts number) and there are plenty of 3rd party products out there for this standard, Token and KCNC Just to name a few.
I think it's even more confusing. There are two BB91-41 BB from Shimano: one A-type which is for MTB and is for BB91 standard Shells and then the B-type which is for BB86 Shells. I am having the B-type thus my frame must be BB86, confused?

Shimano Pressfit 86 Bottom Bracket Cups SM-BB91-41B
High-quality Pressfit bottom bracket cups at Dura-Ace-level. The new bottom bracket design features low overall weight, low Q-factor and increased heel clearance. Easy to install, increased durability because of the larger bearing size. Pressfit 86 bottom bracket cups can be used with specific frames (bottom bracket size 86x41mm) for this new oversize BB standard only. All Shimano Hollowtech-II road cranksets with integrated 24mm spindle are compatible with this bottom bracket.
Shimano Pressfit 91 Bottom Bracket SM-BB91-41A
High-quality Pressfit bottom bracket cups at XTR-level. The new bottom bracket design features low overall weight, low Q-factor and increased heel clearance. Easy to install, increased durability because of the larger bearing size. Pressfit 91 bottom bracket cups can be used with specific frames (bottom bracket size 91x41mm) for this new oversize BB standard only. All Shimano Hollowtech-II cranksets with integrated 24mm spindle are compatible with this bottom bracket.
So my goal would be to avoid the BB change and don't want to pay 100$ for new BB (as I don't have the tools).
Thus I would prefer a Crank/Power meter that fits with my Shimano BB. I understand that Rotor 3D Cranks fits with Shimano BB - anybody has experiences with that combination?
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#11
I might wait until I am in US (~1 month) or Europe (~2month) and bring them back from there, so 5 weeks is anyway expected. Currently assume it's cheaper there than from the Japanese distributor (http://www.zetatrading.jp/product/power2max.html). I haven't found companies with good prices that do international shipping of power-meters that deduct sales-tax. Also Quarq is more expensive in Europe and power2max is more expensive in US.
 

theBlob

Bokeh master
Sep 28, 2011
2,863
1,450
129
...
#12
I bought from a Cali company they shipped quickly and gave me a good price. I ordered a 38 tooth small ring and they accidentally shipped a 110 instead of a 130 so the shipped the 130 without any questions, cost, or asking me to return the 110.

They were good to deal with.

Pro bike supply
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#14
I think it's even more confusing. There are two BB91-41 BB from Shimano: one A-type which is for MTB and is for BB91 standard Shells and then the B-type which is for BB86 Shells. I am having the B-type thus my frame must be BB86, confused?

Shimano Pressfit 86 Bottom Bracket Cups SM-BB91-41B

Shimano Pressfit 91 Bottom Bracket SM-BB91-41A


So my goal would be to avoid the BB change and don't want to pay 100$ for new BB (as I don't have the tools).
Thus I would prefer a Crank/Power meter that fits with my Shimano BB. I understand that Rotor 3D Cranks fits with Shimano BB - anybody has experiences with that combination?
BB90 and BB86 are one and the same in regards to cranks, the only time you need to worry is if you are buying new bottom brackets - in this case no need.
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#15
Just to complete my picture of all the cost involved ...

Did somebody install new press-fit bottom brackets with wood and hammer or is it better to take it to a bike shop (how much do they typically charge?)

proxy.php?image=http%3A%2F%2Fcdn.mos.bikeradar.com%2Fimages%2Fbikes-and-gear%2Fcomponents%2Fcranks%2F1299595217989-1jmdcqso6rs5z-670-70.jpg&hash=44a0887923100bfe61f90fee0f940ac9
 
Likes: mau

AlanW

Maximum Pace
Jan 30, 2007
1,214
435
103
Tokyo
#16
Take a hammer to my frame? No thanks. Cannondale Nakameguro did mine for about 2500 yen if I remember correctly. Or you can buy some adaptors for a headset press (Park Tools) and use that, but it's expensive for a rarely used tool.
 

Malte

Maximum Pace
Sep 26, 2011
496
54
48
Tokyo
#18
I bought from a Cali company they shipped quickly and gave me a good price. I ordered a 38 tooth small ring and they accidentally shipped a 110 instead of a 130 so the shipped the 130 without any questions, cost, or asking me to return the 110.
So you have two power meters now for the price of one ???