Sram cranks 30mm spindles

Discuss light weight issues concerning road bikes & parts.
ti473
Posts: 11
Joined: Thu Jan 25, 2018 9:29 pm

by ti473

Are they replaceable?
I have two sets of cranks, I believe they are 950 and 902. One has the crank length I want to use, but the spindle is slightly longer than I need and might cause me all kinds of headaches as far as chainline and getting the cranks spaced evenly from center of the frame. The other set has the same spindle length of a 386 crankset, which is what I need, but the arms are slightly longer.
Is it possible to swap spindles? There is a hex on the non drive side that says "do not remove", what would happen if I ignore that warning?

alcatraz
Posts: 1355
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Usually the lenth of the spindle is designed to work together with the design of the arms to achive a certain Q-factor for road bikes.

What you propose would probably shrink the Q factor of the resulting crank. If you are a big guy this might not suit you, or the arms could come too close to your chainstays.

What is the spindle length difference? If it's small you could try.

How about posting pictures of both spindles and put up. The sram cranks with removable spiders have undergone a few design changes so your cranks might be different from what people have in mind reading your post.

/a

by Weenie


ti473
Posts: 11
Joined: Thu Jan 25, 2018 9:29 pm

by ti473

the difference is only about 5mm or so. The Crank arms are the same shape (other then the length), so the Q factor differs by that much, I believe it's about 149ish and 155ish.
The ones with the shorter spindle fit into my bottom bracket perfectly with no spacers other than the wavy washer, and would make the cranks equally distant to center of the bike. Also chainline would be ideal with the chain ring in outer position (this is a 1x set up). Like I said this is a 386 frame and these cranks have the same exact spindle length as a 386 crankset even though SRAM doesn't call them that.
The other set of cranks would require spindle spacers, which I guess I would have to put on both sides so that the cranks are centered. This would probably throw off my chain line a little. I supposed I could move the chainring to inner position on the spider but that might still be off.
This one is marked "wide axle" on it. When I bought it I figured it just meant it's wider than a regular BB30 spindle, didn't know that there were that many different sizes.

Anyway I haven't found too much info on this but after digging around a little I don't think it's possible to remove the spindle. I saw stages made different spindles so I assumed they were swappable but those are just to be used with their crank arms.

I am still curious to know what would happen if you tried taking that arm off... I'd rather find out 2nd hand though

UpFromOne
Posts: 726
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

I don't work at SRAM, but in my wrenching experience, the "Do Not Remove" is because the tolerances are so tight (and possibly locktited) that even with the correct tools, you risk breaking that alu bolt.

When I tried it with 900 carbon arms, it took some force and heat but it came apart with nothing broken. A dead hammer was used to release the arm from the spindle. I felt lucky.

So yes it can be done, but it's a crapshoot because they don't just slide apart like the drive side. But the attachment is similar.

sungod
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Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

it's to accomodate wider bb shells...

68mm is bb30
73mm is bb30a

to use the 73mm on a 68mm shell you would use a 2.5mm spacer each side

https://www.amazon.co.uk/SRAM-BB30-Spac ... B0063HLDIW

some sram cranks/spiders are interchangeable - even to the extent of swapping bb30 and gxp - depends on the exact version of component - if the fiiting each end looks the same, i'd think you can swap ok

ti473
Posts: 11
Joined: Thu Jan 25, 2018 9:29 pm

by ti473

sungod wrote:
Sun Feb 25, 2018 7:18 am
it's to accomodate wider bb shells...

68mm is bb30
73mm is bb30a

to use the 73mm on a 68mm shell you would use a 2.5mm spacer each side

https://www.amazon.co.uk/SRAM-BB30-Spac ... B0063HLDIW

some sram cranks/spiders are interchangeable - even to the extent of swapping bb30 and gxp - depends on the exact version of component - if the fiiting each end looks the same, i'd think you can swap ok
This is an 86mm shell and the spindle on the wider cranks is even wider than that. Not a MTB crank either as it came with 53/39 rings.
And I am aware I can space it out but as I said, that would throw my chainline off.
And no you can't swap bb30 with gxp, completely different designs, different splines, different diameters.

ti473
Posts: 11
Joined: Thu Jan 25, 2018 9:29 pm

by ti473

I don't care about the Q factor being a little wider btw, I just don't want my cranks not be centered with the frame

sungod
Posts: 1685
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

ti473 wrote:
Sun Feb 25, 2018 3:32 pm
This is an 86mm shell and the spindle on the wider cranks is even wider than that. Not a MTB crank either as it came with 53/39 rings.
And I am aware I can space it out but as I said, that would throw my chainline off.
And no you can't swap bb30 with gxp, completely different designs, different splines, different diameters.
as i've done this myself - swap bb30 spider onto gxp cranks - it seems that i know more about the subject than you do

glepore
Posts: 1164
Joined: Thu Mar 28, 2013 4:42 pm
Location: Virginia USA

by glepore

The wide axle is for bikes with a 135 rear-https://www.sram.com/sites/default/file ... 7_road.pdf
The 902 comes this way.
The axles are interchangeable, yes, with the caveats above. The bolt is very tight and loctited, and it takes some persuation to remove the crankarm.
Cysco Ti custom Campy SR mechanical (6.9);Cannondale SS Evo Di2 7970 (5.79); Willier Cento Uno Air Di2 9070 (7.0); C40 Mk2 DA 7800 ; Anvil Custom steel Etap;1996 Colnago Technos Record

ti473
Posts: 11
Joined: Thu Jan 25, 2018 9:29 pm

by ti473

sungod wrote:
Sun Feb 25, 2018 3:41 pm
ti473 wrote:
Sun Feb 25, 2018 3:32 pm
This is an 86mm shell and the spindle on the wider cranks is even wider than that. Not a MTB crank either as it came with 53/39 rings.
And I am aware I can space it out but as I said, that would throw my chainline off.
And no you can't swap bb30 with gxp, completely different designs, different splines, different diameters.
as i've done this myself - swap bb30 spider onto gxp cranks - it seems that i know more about the subject than you do
Yes, maybe I misunderstood you. I am aware you can swap the spiders, but i was talking about swapping spindles.

Anyway, I didn't want to chance it and I went the route of putting both cranks for sale and getting the correct one.

On a separate but related note (and since you mentioned spiders)... I've got another frame I'm building that has a gxp bottom bracket and I'm curious to know if the spider offset on a force 1 crank is the same as a force 22. Reason being is that the force 22 would be cheaper to acquire.
Thanks

alcatraz
Posts: 1355
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

If a chainring needs a special offset I'd rather build it into the spider, not the crank.

I'd rather have different spiders than cranks if I were a manufacturer.

Just my guess, I could be wrong.

Have you compared the chainline measurement between 1x and force22? It should be available online. Double road crank (non disc brake) is 43.5mm if I'm not mistaken.

/a

commendatore
Posts: 197
Joined: Mon Dec 30, 2013 1:51 am

by commendatore

I remember reading that that force1 spider is dished inwards to improve chainline.

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MayhemSWE
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Joined: Thu Mar 12, 2015 12:44 pm
Location: Stockholm, Sweden

by MayhemSWE

Aside from graphics I'm quite sure the Force 22 and 1 cranks are identical with all offset built into the chainring only.

JAQ1
Posts: 31
Joined: Sun Mar 27, 2016 7:53 am

by JAQ1

Ok, so I have changed a spindle like this before.

First time was when one of the bearings in my BBright seized and damaged the spindle. I removed it, turned it around and the damage was not located at the bearing anymore.

Then I had a SRAM mtb s2200 carbon crank that wanted to change the chain line on foe 1x, but the s2200 does not have the same step in the crank, so your DS is "flatter" than the NDS. This was to be used in a true PF30 frame (68mm), so there was enough axle to shift it to one side, but then the crank centering is off by about 5mm. In the end I removed the axle completely and used a 109mm cannondale hollowgram axle. This made the q factor smaller by about 8mm, but I could center the crank and get the best chain line.

In the end I found that cannondale, sram, race face and FSA all use exactly the same interface. The only problem with using the stages axles is that the interface is rotated by 90 degrees on the one side, this is because FSA has there interface in a different orientation than the rest.

So if you want to customise Q factor or chainline, you can interchange all the different axles, just get the correct length for your needs.

JAQ1
Posts: 31
Joined: Sun Mar 27, 2016 7:53 am

by JAQ1

I can also add, I think the only reason SRAM does not want you to remove the axle from the NDS is because they save on machining (no thread for the extracting cap), But funtionally, both sides have the exact same interface.

by Weenie


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