#1
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Hollowgram crank in a BSA30 BB? How to?
I have a power meter spider on a set of Hollowgram cranks. I'd like to swap that into my road bike, which has a BSA bottom bracket. I know it can be done but I want to do it correctly without a bunch of futzing around. Any suggestions?
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It's all fun and games until someone puts an eye out... |
#2
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Unfortunately, it can't be done. A HollowGram crank has a 30mm spindle, and are intended to be used on BB30/PF30 bottom brackets, which use bearings internal to a 68mm wide BB shell. A BSA bottom bracket uses a 1.37" (= 35mm) shell, which leaves no room for bearings between the spindle and the shell.
Some cranks with longer 30mm spindles can be used with BSA shells by using bottom bracket with external bears (bearings sit between crankarms and BB shell), but HolloGram cranks don't have spindles long enough to fit bearings between the crankarms and the BB shell. |
#3
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https://cannondaleexperts.com/produc...uperx-ai-kp451 The next issue is removing the spindle since it’s installed via double blind bolt. If you have the cannondale tool or can visit the lbs that’s great, but otherwise it’s a hassle. |
#4
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As others said don’t think this can be done, at least not well. I had a Hollowgram with power meter and sold it when I got a new bike as it wouldn’t play well. Great cranks, but paired best with a true BB30/PF30 frame.
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#5
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I've also come to the conclusion that it can be done, but not well. Thanks all
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It's all fun and games until someone puts an eye out... |
#6
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I don't understand this thread at all. It absolutely can be done well.
First of all, what is a "BSA30" BB? You mean BSA english threaded BB? There are plenty of BSA 30mm spindle external cup BBs you can run. A Hollowgram is a 3 piece crank. 103 (BB30) or 109mm (PF30 typically) spindle for road. If you have a 109 you're probably fine. A few spacers will be needed too. Regardless you can swap the spindle to the desired length - a nice bonus for Hollowgrams vs. conventional 2 piece cranks. And yes you will need the CDale tool. |
#7
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Happy to be corrected, but as they said in high school, please show your work
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Bingham/B.Jackson/Unicoi/Habanero/Raleigh20/429C/BigDummy/S6 |
#8
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I've tried on two separate occasions.
If you can find a very low width 30mm bsa cup (I think Rotors is low) and couple it with either the orange cannondale spindle or a certain Easton spindles you can almost make it work but the q-factor is all wrong since the cranks are meant for a more narrow bb than you're trying to put them on Chainring can be solved with a wolf tooth direct mount chainring flipped around
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Meriwether All-Road |
#9
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Quote:
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Bingham/B.Jackson/Unicoi/Habanero/Raleigh20/429C/BigDummy/S6 |
#10
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I have a set of the Rotor BSA 30 cups coming so I'll try that and report back.
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It's all fun and games until someone puts an eye out... |
#12
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Quote:
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The 3 piece crank will therefore need a wider spindle just to fit in a bsa 30 bb, since the bsa bb plus bb shell is min 18mm wider than the bsa or pf30 shells. And even if you get the wider spindle the chainline will be moved outboard since tbe chainrings are mounted to the ds arm, either directly or on a spider.and similarly since the arms are moved out 9mm each way, Q factor / pedal position will be moved out 9mm each way The “bonus” of that 3 part crankset is a negative since a spider to compensate for the offset chainline isn’t available, and the Q factor changes so much. Just look at the shape of the cannondale crank arms and how they splay out from the axle/spindle. Vs the straighter arms of cranksets made for installation in either bsa, bb386 or other wider bb systems. Or this photo showing fsa crankarm differences, top are bb386 arm and bottom is the bb30/pf30 arm. |
#13
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There were several threads on Ww regarding this type of conversion. The last time I considered it you needed the mtb spindle with the shoulder machined off and the Zipp Vumaquad bb. Not sure if that is still the case as I see cannodaleexperts selling a few different length spindles.
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#14
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Ah good clarification above. I was thinking put on a wider spindle and space it out with shims. I suppose the chainline would be too far off. FWIW I've had good luck running newer PF30 cranks on external BB30 BSA BBs the few times I've tried it.
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