# Road crankset with 104 BCD 4-bolt spider?



## David Lewis (May 2, 2013)

I have a road bike, a Renovo Elwood, which is built up with a Gates belt and Alfine-11 hub. To get the gearing I want, I need to use a 4-bolt 104 BCD spider, but I would like a low Q-factor road crank. The 68 mm outboard bottom bracket takes a 24 mm spindle or SRAM GXP, and I want 175 mm arms in black if possible. Any ideas?

Best,
David


----------



## bikerjulio (Jan 19, 2010)

this? Truvativ X0 10-Speed Crankset | SRAM

May not be everything you want. But then nothing ever is.


----------



## David Lewis (May 2, 2013)

Thanks for the suggestion. But that crank has about the same Q-factor as the Truvativ Stylo I'm using now: about 175 mm. A road crank like the SRAM S300 has about a 145 mm Q-factor, a substantial difference, and if I can't get close to that, then it isn't worth the effort and expense to swap.

Best,
David


----------



## Nater (Feb 7, 2003)

The SRAM XX1 crankset is available in a 156mm Q factor version with a GXP BB spindle.

It doesn't come with a 104 BCD spider on it (I believe it has an assymetrical 76mm BCD spider). The spider is removable though and you could install a 104BCD spider from an X0 or X9 cranks. Or, I'd bet that Gates may make chainrings (belt wheels?) to fit the XX1 spider as is.


----------



## kbiker3111 (Nov 7, 2006)

You'll need to go to a square taper BB. There are no <145 qfactor cranks with 24mm spindles. Check out White Industries. They use a trick spider that allows multiple chainring sizes and they're square taper so you can go as narrow as your chainstays allow. Middleburn also has some options that might work for you but their official road cranks are MIA.

The other option is to go on Ebay or scour the LBS's for old square taper mountain bike cranks that you could go double with. I have a set of Race Face square taper 94 bcds that are bad ass.


----------



## Nater (Feb 7, 2003)

kbiker3111 said:


> Check out White Industries.


It would be hard to get a belt drive ring on a White Ind cranks...they don't really have a spider perse...the ring is the spider. In the case of the road cranks, the big ring is the spider. 

You could have someone make you a 104 bcd spider for the White Ind spline pattern though. Probably a one-off and expensive.

I don't think the Gates Belt Drive rings come in 94mm BCD either...not sure about that though.


----------



## Nater (Feb 7, 2003)

To the OP:

What tooth count are you going for on the chainring? A quick perusal shows that the only tooth count from Gates that is limited to the 104BCD is the 39tooth. It might be easier to achieve all you're looking for by going slightly bigger on the chainring as well as the cog on the Alfine. Assuming there is a belt length that works for your cog/chainring/chainstay length combo.


----------



## David Lewis (May 2, 2013)

Nater said:


> To the OP:
> 
> What tooth count are you going for on the chainring? A quick perusal shows that the only tooth count from Gates that is limited to the 104BCD is the 39tooth.


I have a 42-tooth front and 24-tooth rear. Unfortunately, the bike has a Philcentric bottom bracket that only gives a little more than +/- 3 mm, and 440 mm chainstay length. The only combination of existing Gates components that allows are 42/24 with a 113-tooth belt, or 46/24 with a 115-tooth belt. I had hoped to be able to use a 46/26, but it would require a 116-tooth belt, which they don't make. I had actually purchased the parts, including an SRAM S-300 crank that does have a GXP spindle and 144 mm Q-factor, but when we went to install it we realized that it couldn't be tensioned. I will check out the XX1 option. Thanks for the help.

Best,
David


----------



## David Lewis (May 2, 2013)

Nater said:


> The SRAM XX1 crankset is available in a 156mm Q factor version with a GXP BB spindle.


Do all the SRAM spiders have the same interface? The Force 22, for instance, has carbon arms and a forged spider; would that spider be removable and interchangeable with a 104?


----------



## David Lewis (May 2, 2013)

Actually, the S900 GXP is also 145 mm Q-factor and looks even more like the spider should be replaceable. Does anyone know? Would one of the spiders from North Shore Billet work?

David


----------



## David Lewis (May 2, 2013)

To answer my own question, in case it helps anybody else: the SRAM S900 cranks are 145 mm Q-factor. The spider is indeed removable. The spiders that North Shore Billet makes for the Truvativ X0 cranks have the same spline interface and base curve, and fit perfectly. I got the 1x10 one, which gives me exactly the chainline I need, but Chris at North Shore Billet said they had a customer who used the 2x10 one on an S900 crank to get a double setup on a touring bike with smaller chainrings than the stock 130 mm BCD would allow.

Best,
David


----------



## VanMich (Sep 3, 2013)

David, thanks. I don't understand all about your config, I' m french, but the important thing is that I could fix a 104BCD ring on road cranks! Maybe there are other possibilities than S900 and NSB?
Do you know if every S900 cranks have the removable spider, considering the year of fabrication?
My plan is to put a single 34t O'Symetric ring on my 10spd cyclo-cross bike (same measures as a road bike), so only in 104BCD, and I don't know about chainline details and other stuff, but I think it will be close to perfection compared to a single MTB crankset! What do you think?


----------



## David Lewis (May 2, 2013)

All the S900 cranks have the removable spider, but the ones manufactured before 2012 have arms whose base is a different shape. It looks like the spiders that NSB made for the X9 cranks would fit, but I have not tried it. Having now ridden the combination for about 1K kilometers, I am very pleased with the way my setup worked out, and can highly recommend it. It is very easy to feel the difference between the 175 mm Q-factor of mountain bike cranks and the 145 mm Q-factor of the S900, especially when out of the saddle.

Best,
David

Best,
David


----------



## VanMich (Sep 3, 2013)

Thanks, it looks like a vital info! (for the "before 2012" no compatibility)
I've just asked many confirmations of that to dealers.. One response, for a french store: uncompatible anyway 'cause cranks are carbon and NSB spider is metal! But NSB just told me they had several customers that did like you (XO or X9 spider).. So before buying I wait for more answers to be sure.

For the Q-factors, I constantly switch from MTB to TT road (triathlons cross or road) and 30mm QF + larger pedals on MTB, not cool! But can't do anything for the MTB, my heels come already close to the rear tubes!


----------



## David Lewis (May 2, 2013)

VanMich said:


> One response, for a french store: uncompatible anyway 'cause cranks are carbon and NSB spider is metal!


I'd avoid that dealer. The S900 crank has carbon arms and a removable aluminum spider that is attached with three screws and a spline. That is what allows the NSB spider to be used: it has the same spline pattern as the stock spider.

Best,
David


----------



## VanMich (Sep 3, 2013)

I insist a lil', I have trouble finding infos to confirm that the S900 cranks are for sure compatible with the NSB spider (mono for XO or X9) only if the S900 is manufactured 2012 or later (cause of interface change). I've eMailed many shops saling those, to know wich year are the cranks from, no respond.
Thanks


----------



## David Lewis (May 2, 2013)

They are fairly easy to tell apart. The older one, which you can see here, has a rounded end to its arms. The newer one, here, has a squared-off base to its arms. The former might work with the X9 spider, the latter definitely does work with the X0 one.

Best,
David


----------



## VanMich (Sep 3, 2013)

Thanks again, David. Your last post completely re-assured me, plus a vendor confirmed his S950 was 2013, so I've bought the combo. I'll write again when it's installed
You're the best in deed, David :thumbsup:
mV


----------



## VanMich (Sep 3, 2013)

I still need help!!
(The 1x10 XO NSB spider and 2013 S950 cranks: compatible, thanks again)
But now I' m in trouble with the S950 instal:
the cranks won't fit my Shimano GXP BB, cause they are flat, I mean they totally come in contact with the all BB, not only the rolling surface, but the metal circle too. And it's the same with both the original and the NSB spider. Do I have to put a "spacer" (not included in the box)? or must I buy a Sram GXP BB (I don't see how it will be different, Sram GXP BBs look all flat too)?
Thanks
mV


----------



## Nater (Feb 7, 2003)

There is no such beast as a "Shimano GXP BB." You'll definitely need a SRAM BB to use those cranks. Non-drive side bearings are different sizes between SRAM and Shimano.


----------



## David Lewis (May 2, 2013)

The GXP crank is different from the Shimano Hollowtech II. The Shimano has a 24 mm spindle. The GXP cranks have a 24 mm spindle that steps down to 22 mm when it goes through the non-drive-side bearing, which is what locates it laterally. You either need a GXP bottom bracket or an adapter that sleeves the non-drive-side bearing down to 22 mm.

Best,
David


----------



## VanMich (Sep 3, 2013)

thanks Nater, I was just about to erase my question, cause I found infos on the net (easily!).. But so I remembered I had an old tired Truvativ BB, I tried it but not working neither, as there's a space, can't tighten more. I guess when I'll buy a Sram BB it'll have spacers and I'll finally have my bike complete for my 1st cyclocross, sunday!


----------



## VanMich (Sep 3, 2013)

And finally, thanks again Nater, I have my beast complete 
recap: CycloCross bike, Sram S950 Cranks with NSB XO spider, O'Symetric ring (34tth,104BCD).. Voilà:






(Have it since october, now I switch back to round ring to test the difference on cross courses)


----------



## jimbond (Jan 12, 2014)

Like David, I'm also looking for a low Q-factor crank solution for my Pedersen bike with CDX belt drive. I have arthritic knees, so need as low as possible, while still clearing the belt.

Did you manage to get a 4-bolt spider for your front sprocket, David? (All the links keep pointing me towards a five bolt affair.) 

Does this SRAM crank come in 700mm length?

And could you please explain what '1x10' means? A picture, like VanMich's, would help heaps. As I'm based in UK, I don't want to be ordering internationally from NSB in the States and getting it wrong! 

Finally, what's the difference between S900 and S950?

BW, Jim


----------

