165mm cranksets for hill climbing

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fixiedave
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Joined: Wed Nov 04, 2015 8:02 pm

by fixiedave

I'm picking out parts for a mid-budget, single-chainring, WW hill climb time trial bike. The rider is lightweight and small, so she can get away with an aluminum cassette, but needs 165mm cranks. We're looking for low gear combinations of 34/42, 29/36, or slightly lower.

For a baseline, I was considering FSA SL-K Light cranks with a single 34T (~560g incl. BB) and a Free Ranger Response 11-42 cassette (260g). I believe there are cranksets out there that would allow her to use an 11-36 cassette (160g), save a few grams, and provide opportunity to switch to a smaller chainring if 34/42 turns out to be too hard.

So, what cranksets exist in 165mm length, road q-factors (<150mm), 29T chainring or smaller (i.e. 94mm bcd or smaller), and weigh less than 660g including BB and chainring? I'll get the list started

Lightning Carbon cranks with 94mmm bcd double spider, BB30 BB, and some other brand 29T chainring, ~480g, ~$720
Specialites TA Carmina with 94mm double spider, AXIX BB, and 29T chainring, ~650g, ~$470

I haven't seen good weights on these:
Grand Cru 50.4 BCD Crankset MK II
Specialites TA Pro 5 Vis
Sugino OX601D
Middleburn (do they even make 165mm?)

by Weenie


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Valbrona
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by Valbrona

SRAM do a range of triple, double and single removable spiders with differing BCDs.

fixiedave
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by fixiedave

Valbrona wrote:SRAM do a range of triple, double and single removable spiders with differing BCDs.

Thanks for the tip. It would appear that SRAM makes a few lightweight 165mm cranks with removable spiders: Force 1, Force 22, as well as the heavier Rival 1 and 22 versions.

From there, it looks like SRAM has a whole range of MTB spiders available. The single ring options from absoluteblack.cc ($65, ~50g) look perfect for this bike.

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djconnel
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by djconnel

I like my Lightnings.
Last edited by djconnel on Thu Nov 05, 2015 12:06 am, edited 2 times in total.

Nefarious86
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by Nefarious86

165mm Force 1/22 with a Norrow wide direct mount ring?
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Valbrona
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by Valbrona

However, note that SRAM spiders are not fully interchangeable.

You get GXP and BB30 ones.
And you get ones for alloy crank arms and ones for carbon crank arms.

Marin
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by Marin

FYI, I got myself a SRAM MTB spider and it took some dremeling before would fully clear my Force 22 crankarm.

Nefarious86
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by Nefarious86

Valbrona wrote:However, note that SRAM spiders are not fully interchangeable.

You get GXP and BB30 ones.
And you get ones for alloy crank arms and ones for carbon crank arms.

Skip the spider issue and go direct mount ;) simples.
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Valbrona
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by Valbrona

fixiedave wrote:We're looking for low gear combinations of 34/42, 29/36, or slightly lower.


Do you know what you are doing?

1/ You'll get loads of chainslap.
2/ You might not be able to get the FD low enough down the seat tube on account of either the fixing bracket not offering enough adjustment or the bottom of the FD cage contacting the RH chainstay.
3/ You will have the chain jam in between the FD cage and big chainring if it is road style on account of curvature of the cage.
4/ Many FDs - both road and MTB - require a difference of at least 8 or 10 teeth between chainrings for them to work properly.

Valbrona
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Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

Marin wrote:FYI, I got myself a SRAM MTB spider and it took some dremeling before would fully clear my Force 22 crankarm.


You maybe got the wrong pattern spider then. SRAM alloy crank arms are shaped quite differently from their carbon crank arms, hence the existence of two patterns of SRAM spider in both GXP and BB30 formats.

fixiedave
Posts: 3
Joined: Wed Nov 04, 2015 8:02 pm

by fixiedave

Valbrona wrote:
fixiedave wrote:We're looking for low gear combinations of 34/42, 29/36, or slightly lower.


Do you know what you are doing?

1/ You'll get loads of chainslap.
2/ You might not be able to get the FD low enough down the seat tube on account of either the fixing bracket not offering enough adjustment or the bottom of the FD cage contacting the RH chainstay.
3/ You will have the chain jam in between the FD cage and big chainring if it is road style on account of curvature of the cage.
4/ Many FDs - both road and MTB - require a difference of at least 8 or 10 teeth between chainrings for them to work properly.


This super-low gear setup will be 1X 10-speed, without front derailleur. I'll use a SRAM X0 (or X9 or XX) rear derailleur with roller clutch to keep the chain from bouncing off.

deek
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by deek

The SRAM Force cranksets aren't that light. The Red cranksets are very light without the rings (especially BB30), but they can only go down to 34T.

I'd probably go Lightning, Specialized, or Cannondale. Cannondale would probably be the most turnkey since they have MTB spiders that will easily mount to the same cranks. Specialized and Lightning might be the same way but I'm not as familiar.

DCnoJ
Posts: 104
Joined: Wed Mar 23, 2011 6:50 am

by DCnoJ

No mention of Rotor 3D+?
- Not crazy light, but not heavy by no means
- Universal BB, will fit on any frame
- Huge length options: 150-180
- Interchangeable spider
- A ton of powermeter options (spider)
- Groupset neutral
- Great customer service

by Weenie


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