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Discussion Starter · #1 ·
Aaargh!

Having just received delivery of a lovely new Scott Genius frameset, it's only now I realise I need a 73mm E-type bottom bracket (I think it has been mentioned on here before, but I obviously didn't pay attention). "Why?" I scream (on inspection the answer is obvious - the down tube is that wide at the BB, so no machining it down even if I wanted to do that). My Strike was just fine with a 68 E-type, as I just used a 73mm BB with a spacer in the non-drive side, but 73 with an E-type is another matter. The question is not so much what light BB can I get for a 73 E-type, but what BB - I have an FSA ISIS chainset, and currently run an AC? I think I am finding as Nino did with his Scale that it's all very well getting a lightweight frameset, but if you can't get lightweight bits to fit it's all wasted - unfortunately in my case a custom mount for a bolt on doesn't seem an option, as there's no conventional round seat tube. Any thoughts - Nino, what were you thinking off for your Scale before you ditched the E-type? Is it possible to get shims to put inside my AC cups (as you do with an FRM CU2 to make it work with a 73) to expand the driveside?

p.s. The Genius is 2150g in M without the remote, so 10g lighter than the spec., plus 90g for the non cut-down and tuned remote.
 

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I don't understand the e-type problem.

Any e-type should work just fine. Do you have an issue with chainline? Shimano XTR 960E is ~145 grams and I just happen to have one for sale on eBay. I dont like e-type either. You may be able to find a clamp that will allow you to use a road derailleur.
 

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Dump ISIS.

That's what I get for trying to read so late at night I guess. The American Classic ISIS BB I had wouldn't have been able to use spacers, but the newer version may. The FRM ended up being my favorite ISIS BB since the bearings were so easy to replace and it was so versatile & light. I still dumped ISIS anyway due to all the bearing issues. Even if they're easy to replace, it gets tedious doing it every couple of weeks or months if you're lucky. I think your fancy new frame deserves better!
 

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I'd love to - had my eye on a nice Extralite integrated set, but unfortunately that won't work with 73 and E-type. The only obvious integrated option is Shimano, and I'm not keen on paying lots to get something that weighs more than my current FSA / AC combo, along with a wide Q-factor.
 

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Yeah it's too bad there really aren't any good lighter weight alternatives to ISIS yet. The ISIS splines aren't the problem, just those darn tiny bearings. Will that MegaEXO ISIS from FRM work with your cranks? Heavier than AC, but should last much longer. My AC lasted only a few rides.

I went with the heavy RaceFace Deus XC cranksets since I got one set as a warranty replacement for a cracked Next LP set. The external bearings do seem to hold up better than any ISIS did for me

Have you checked into the FRM external crankset? I remember considering that one, but it wasn't available at the time. I don't think it's as light as many ISIS setups, but lighter than most other external types. Q is too wide on most these days. The Deus is 165 mm which is just borderline for me. I liked that Crank Brothers set someone posted last week. Maybe they will do an external bearing version that is low Q and light.
 

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Discussion Starter · #7 ·
Did your FRM BB come with spacers? I'm not sure if you got my comment on this in the first post.

With the (original) FRM BB you put spacers inside the cups, between the cups and bearings to space the cups out to make it work with a 73mm frame. For a 68mm frame you didn't use spacers. The AC works the other way round, with spacers between the cups and frame for 68 and no spacers for 73. I was just wondering whether it would be possible to put one spacer from an FRM BB inside an AC cup (and using no AC spacers) to make the AC BB work with 73 E-type. I note the new version doesn't include these spacers, so presumably I couldn't get them anymore, and unfortunately my (deceased) FRM BB didn't come with any. I don't suppose you (or anybody else) has some of these I could acquire?
 

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I had a few of the FRM BBs &, yes, one, the newer one I believe, came with spacers & instructions for pretty much any configuration - very nice. Unfortunately, I've sold both those bottom brackets. The newer one sold yesterday! My AC BB did not have replaceable bearings.

I think I have some of the external spacers lying around, but none of the internal - sorry. Perhaps you could give Stan @ notubes.com a call - he may have some & I bet he'll help if he does. Another potential source would be light-bikes.com. Good luck.
 

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Isn't it possible to use somekind of square tapered bottom bracket. I was thinking of this setup, together with Storck Powerarms on my Genius. For now i'm using a FSA Megaexo crankset, but was thinking of a lighter setup. On my Scale I use a FSA Team Issue crankset in Octalink but this is too heavy too. I'm not very familiar with al those sizes for bottombrackets, but was hoping that a square tapered one worked. U could find light ones in all kind of sizes.
 

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BIG problem...

dennis rides Scott said:
Isn't it possible to use somekind of square tapered bottom bracket. I was thinking of this setup, together with Storck Powerarms on my Genius. For now i'm using a FSA Megaexo crankset, but was thinking of a lighter setup. On my Scale I use a FSA Team Issue crankset in Octalink but this is too heavy too. I'm not very familiar with al those sizes for bottombrackets, but was hoping that a square tapered one worked. U could find light ones in all kind of sizes.
the E-type derailleur setup was one of the main reasons i hesitated so long to get a Scale frameset. you are really stuck if you want a light setup!
so far i haven't found a single BB that matches 73 BB shell AND the E-type derailleur. that was the main reason to dump the E-type all the way and go for a road derailleur with BTP-38mm adapter clamp. it weighs only 77g and allows you to use regular BBs. BUT this means you need to change the cable routing on your frame which is done pretty easily but is still a hassle to get the parts for and it is a shame if you need to work on such nice frames...

anyway - i think some spacers inside any BB will solve your problem quite easily. you will need ca. 2mm on both sides inside the cups.

if i would have to go with integrated cranks i'd have a look at the FRM.

pictured below is my adapted roadie front derailleur:
"old" 9s 7700 Dura Ace with 6g BTP adapter clamp

and some pics of the changed cable routing on my Scale:
regular plastic guide below the BB (road derailleurs are all bottom pull) and glued on cablestops at the downtube
 

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dennis rides Scott said:
Just noticed that FSA have al there platinum brackets in 73mm E-type. The lightest one is around 190gram.
I had an one of those, and it was the shortest lived ISIS BB I've owned, without even the possibility to change bearings as with FRM and AC.

I have potentially found a solution now. As the left cup on the AC is floating I am just using that without any spacers, which is something you could do with any BB with a floating left cup. On examination I don't think it's possible to put extra spacers inside the right cup, as the position of that is fixed by a stop behind the bearing. This does mean the whole thing is offset to the right 2.5mm compared to where it nominally should be, but everything seems to fit, and on the right side it's only equivalent to having a 118 BB, which is what I think you'd need anyway for 73 E-type to give clearance, so it doesn't particularly mess up the chainline. The only remaining issue is the slightly offset pedalling platform - I don't think it will be an issue, but I haven't ridden the bike yet, and anyway there are certainly cranks out there with more offset than that built in (being a BB geek, at least one length of Shimano square taper BB isn't symmetrical). If it really is a problem I can just add a 5mm pedla spacer on the left!

Looks like I'll be sticking to ISIS for a bit longer than I planned (loathe to dump my investment for no weight advantage with Sh or FRM), though it does seem that the touted advantage of bearing life isn't a reality with integrated cranks anyway.
 

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should work...

Cath said:
I think this is a lightweight solution for Scale:

http://www.atik.cc/htm/products18_CRANKSETS.htm

ATIK AT 1160 with ceramic bearings, titanium spindle. Target weight 720 g.

External BB that I guess is E-type compatible, since it's based on the Token TK200EX-AL.

Haven't tried it, though.
i'm about to get them...
 

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Batas said:
Nino, what is the Q-Factor of the Atik relatively to XTR 07? And the chainline?

Using the Atik with e-type doesn't push the crank to the right? What would be the chainline?

So many questions... I know...
i have no idea. i just weighed those cranks at Eurobike. we will see.
 

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Since this thread has been resurrected, an update from me is probably due. I've been riding on the setup I suggested back in December last year for the past 11 months, and I really can't say I notice the offset, or any chainline problems. Is a potential solution for anybody with a Genius or Scale.

Of course another potential solution is the Clavicula - I put myself down on the waiting list, but by the time they were available had decided they were just too expensive.
 
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