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Discussion Starter · #1 ·
Hey Gang...

From the tool perspective are there differences on the external Bottom Bracket systems? MegaExo, Truvativ GXP, Race Face, and Shimano? And in the Shimano family are there differences? I guess what it comes down to is are they using the same spline profile, tooth count and diameters for the bearing cups?

I'm just asking because there is no clear cut descriptions on the tools that are out there Shimano, Pedro's, Truvativ, and others on wether or not they are compatible...

I also am wondering, most of the tools seem to be spanners, rather than socket style... How are you expected to put proper torque on the parts with a spanner versus a socket on Torque wrench?

Thoughts or experiences from you all???

Thanks.
 

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all the cups i've worked on have had the same interface. shimano, truvativ, fsa.

shimano makes a tool (but doesn't seem to advertise it) that'll fit onto your 1/4" (i believe) drive torque wrench.. TL-FC33
 

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Discussion Starter · #3 ·
Thanks!

fore said:
all the cups i've worked on have had the same interface. shimano, truvativ, fsa.

shimano makes a tool (but doesn't seem to advertise it) that'll fit onto your 1/4" (i believe) drive torque wrench.. TL-FC33
Ahhh, cool! The voice of experience is always welcome... I had seen pictures of that tool on some store's websites, but just can't tell much beyond that...

Sounds like for some reason on this technology we've avoided propriatary splines? Very Unusual as Shimano was first to market on it from the big component companies.

Well now I've just got to find a source for that tool...

Thanks a lot!
 

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www.biketoolsetc.com

sengert said:
Well now I've just got to find a source for that tool...
Thanks a lot!
Ha! I just ordered one a couple days ago from biketoolsetc.com. I've been using the Park Tool BBT-9 but never felt comfortable that I couldn't torque to spec. I happened to stumble on Shimano's TL-FC33 tool on their web site.
 

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fore said:
all the cups i've worked on have had the same interface. shimano, truvativ, fsa.

shimano makes a tool (but doesn't seem to advertise it) that'll fit onto your 1/4" (i believe) drive torque wrench.. TL-FC33
I was wrong about that. It's actually a 1/2" drive, not a 1/4".
 

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Discussion Starter · #6 ·
Cletus said:
Ha! I just ordered one a couple days ago from biketoolsetc.com.
Ahhhh Cool! :cool:

I just ordered one yesterday from Universalcycles.com... I wonder if it would do some public good to also list the bottom bracket (BB) that we are using the tool with? Searches for the various cranksets and BB's would find this link in the future. This also was the root of my problem, as none of the sites will list compatibility, or verify at least that they all really are using the same spline.

I'm putting in a Truvativ GXP from their Stylo Team crankset.

Thanks for the replies!!! ;)

T.
 

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pedros

been using the pedros wrench for the last 11 months in the shop(used a lot)fits em all and shows no sign of wear, forget who makes it but the latest issue of dirt rag has a nice lookin one in the tested section.
 

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Shimano, Raceface, and FSA all use compatable bottom brackets. Shimano and FSA share the same crank interface. It allows the mechanic to set bearing tension and they uses pinch bolts to maintain it. RaceFace and TruVativ use a modified ISIS interface. The crank arm presses onto the spindle by a predetermined amount. It does not allow the mechanic to independently adjust bearing preload or accomodate for a frame that may be out of spec on bb width.

Having said that I have run Shimano, truvativ, and fsa setups within the last 1.5 years without any problems from any of them.
 

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set bearing preload? on a shimano hollowtech 2 bottom bracket?

i install 3-5 of those a day, 5 days a week, and i can't recall a time i've ever been able to alter the bearing tension. all that "preload" bolt does is ensure that the crankarms are snug against the bottom bracket to prevent the crank/spindle assembly from sliding around laterally. it has no effect on bearing preload. (unless of course you were to modify the tool for that bolt to fit into a crescent wrench and put an unreasonable amount of torque on it. then it might. but that'd be stupid.)

and as far as bottom bracket shells being "out of spec" in regards to width, what in the hell are you talking about?
 

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fore said:
set bearing preload? on a shimano hollowtech 2 bottom bracket?

i install 3-5 of those a day, 5 days a week, and i can't recall a time i've ever been able to alter the bearing tension. all that "preload" bolt does is ensure that the crankarms are snug against the bottom bracket to prevent the crank/spindle assembly from sliding around laterally. it has no effect on bearing preload. (unless of course you were to modify the tool for that bolt to fit into a crescent wrench and put an unreasonable amount of torque on it. then it might. but that'd be stupid.)

and as far as bottom bracket shells being "out of spec" in regards to width, what in the hell are you talking about?
Aren't hollowtech 2 and external bb bup two different. I think he is referring to the small plastic piece that you use to snug up the preload on the xt 760 model crankset..?
 

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jason74 said:
Aren't hollowtech 2 and external bb bup two different. I think he is referring to the small plastic piece that you use to snug up the preload on the xt 760 model crankset..?
Hollowtech II is Shimano's name for their outboard bearing system.

The bearings are not adjustable. There is no "preload" insofar as adjusting the bearings. The only preload you can really speak of with that system is that splined bolt that threads into the spindle from the non-drive side after you install the non-drive crank, and that has nothing to do with bearing pressure. All that does is ensure that the crankarms are snug up against the bottom bracket cups, eliminating any lateral movement by the crank assembly. Then you cinch it all together with the two pinch bolts on the non-drive crank.

I suppose if one were to really get that splined bolt super super super tight, it might be possible to bind something up somewhere so the cranks don't spin as well as they should, but doing that would be stupid. There's a reason the tool for that bolt is a little nylon hand tool, rather than something you'd attach to a wrench.
 

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fore said:
set bearing preload? on a shimano hollowtech 2 bottom bracket?
and as far as bottom bracket shells being "out of spec" in regards to width, what in the hell are you talking about?
It's pretty common to find bottom bracket shells that are not the correct width. If you really wanted to do the job right, you'd be measuring the shell width & facing it before installing any bottom bracket. Some bottom brackets are more sensitive to width errors than others. As far as frames go, in my experience, the "higher end" frames have been the worst by far in this respect. I've had some that were nearly 3 mm too wide. It takes a long time, even with a sharp facing tool, to remove that much material!
 

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B R H said:
It's pretty common to find bottom bracket shells that are not the correct width. If you really wanted to do the job right, you'd be measuring the shell width & facing it before installing any bottom bracket. Some bottom brackets are more sensitive to width errors than others. As far as frames go, in my experience, the "higher end" frames have been the worst by far in this respect. I've had some that were nearly 3 mm too wide. It takes a long time, even with a sharp facing tool, to remove that much material!
With the outboard bearing setups (at least shimano's), those handy-dandy little shims kinda make the whole bb shell width issue moot, don't they?
 

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I'm not familiar with the Shimano setup, but shell width is still important with RaceFace X-type bottom brackets. I believe their spec is that the shell be within +/- 0.25 mm of correct to maintain warranty coverage (68 or 73 mm, whichever you have). I'd be willing to bet that Shimano has a similar spec although it may be more relaxed. The Shimano shims are 2.5 mm also, right? If so, those are only used to set the bottom bracket up for use with 68 vs. 73 mm shells and normal vs. E-type derailleurs. RaceFace bottom brackets also come with bearing pre-load spacers, but these are what allow the +/- 0.25 mm tolerance in the first place. My guess is that the pinch bolt systems simply eliminate the need for the pre-load spacers.

The best frame I've had to date was a Giant XTC Composite. The bottom bracket shell was between 68.0 & 68.25 mm right out of the box! The worst was a Titus Racer X followed closely by an Ellsworth Truth. Facing a frame is still a good idea if you care about quality.
 

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Discussion Starter · #15 ·
sengert said:
I just ordered one yesterday from Universalcycles.com...

I'm putting in a Truvativ GXP from their Stylo Team crankset.
Just a follow up to the orignial intent of this posting...

I did successfully install the Truvativ GXP bottom bracket using the Shimano installation tool. VERY nice! 1/2" standard drive to put it directly onto my Torque wrench.

:)

Tony
 

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fore said:
I suppose if one were to really get that splined bolt super super super tight, it might be possible to bind something up somewhere so the cranks don't spin as well as they should, but doing that would be stupid. There's a reason the tool for that bolt is a little nylon hand tool, rather than something you'd attach to a wrench.
Thats exactly what they are refering to by setting the preload. Shimano was actually pretty clever in using that plastic knob tool. It only allows enough force to snuch the arms without squashing the bearings. Their cranks also allow for some slack as far as where they clamp on the spindle so BB shell tolerances are not as critical. Other manufactuers chose to use hex wrenches and bolts to snug the crank arms which can badly preload the bearings given most people will have the tendency to turn them real tight.

With Race Face x-type cranks in particular the shell width must be very exact. Their cranks have to firmly bottom out on the spline to be properly set. They always need to bottom out at a specific set length. It can take up to like 70 foot pounds for this. If the BB shell is too long out of spec the bearings will be squashed to the point the crank barely turns. Thats why they bring a set of elastomers to fine tune clearance.
 

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B R H said:
I'd be willing to bet that Shimano has a similar spec although it may be more relaxed.
Yes the Shimano tolerances are more relaxed. There's a basic difference between the two designs. Race Face essentially built an oversized ISIS spline. It has the same quirks. For the arms to properly and securely mount they (it actually since its only one side) has to solidly bottom out on the spline so the bolt can keep it pinched down and stay under pressure. That means the spindle width is always exactly constant. The BB shell in between either fits or it doesn't.

On the Shimano design the arms are not kept tight by a bolt that pushes them inwards. Instead the arms slide back and forth loosely on splines of the splindle before the pinch bolts are tightened. You then hand tighted the crank with this lockring like bolt until they go snug on the BB. It doesn't matter much if the arms slide in a bit more or less on the spindle as a result of the BB width because the insertion depth on the spindle is irrelevant after a certain margin. What will keep the crank arm fixed on the spindle are the pinch bolts that tighten the arm opening over the splines. The lockiring also has an inner lip that gets pinched when the pichbolts are tight. This keeps it from unthreading and is also what stops the arm from wanting to slip off the spindle.
 
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