More 2×10 Options: Custom Little Rings

Let’s go over what’s great: MTB 2×10 Drivetrain, 29ers, Titanium, Pushing limits, Supporting small businesses. But, nothing is without its pitfalls.

With the introduction of the 2×10 drivetrain we’ve also been introduced to the 80/120 Chainring BCD. Limiting the smallest ring to a (some would say) gigantic size of 26t. Paired with the new 36t cassette makes for a bigger (harder) granny gear, compared to the typical triple crankset set up with 22t little ring and 34t in the rear. And the big ring…well, if you’re spinning out a 42-12, this doesn’t matter to you.

If having more options and dialing in your bike interests you click on to read and see more…

Introductory Math:
22×34 = 0.65 (11:17) – typical 3×9
26×36 = 0.72 (13:18) – small 2×10

Put in simpler terms, the 2×10 granny gear is about the same as one gear harder then your granny with your 3×9 setup.  So what? Big deal, you say. Tell yourself that in the middle of that 30 min climb everyone warned you about that you didn’t realize just how steep it was. Not everyone can roll up the climbs with an Ulrich-like cadence. Some of us really need that easy, wimpy gear ratio! I’m sure anyone who has ever been mountain biking can recall a time when they went to shift to the granny gear, just to realize that they were already in the granny. Bummer! Point being, even though the new 2×10 granny gear is just slightly harder then what you’re used to, harder is still harder.

Not everyone is interested in upgrading to a 2×10. I certainly wasn’t. But… when someone says to me “I’ve got an new XX/XO drivetrain for dirt cheap. Do you want it?” Hell yes I do! What about the harder gear? I did my homework and the math when the 2×10 hit the market. For this price…who cares! I can deal with it. And I did…for 2 months. After the novelty of the great deal wore off, I realized I was stuck with a harder gear that I couldn’t and didn’t want to push. So, I did what any other self respecting mountain biker would do… I asked the MTBR forums. That’s where I was introduced to many custom machinists who make chainrings.

More Math:
22×34 = 0.65 (11:17) – This is my old set up, I want to get as close to this as possible.

Keeping the new 36t cassette as a constant:
26×36 = 0.72 (13:18) – Got it. Don’t want it
25×36 = 0.69 (25:36) – Pretty good!
24×36 = 0.67 (2:3) – Almost exactly the same!

Then I was told by all the machinists contacted that the smallest possible chainring with a 80 BCD is 26t. I knew by looking at the XX ring on my bike that there was a pretty good chance a 25t could be made, so I contact Mattais, a Swedish engineer that likes to experiment with a lighter, faster, better approach to whatever bike part he feels like working on. How does he make a living? I don’t know, maybe Sweden’s got a high bank-rolling weight weenie crowd? I inquire about either a 25t or 24t possibility. He said 24t is questionable but 25t…he could definitely make!

€55.00 ($76) and 6 weeks later, I’ve got a sexy 25t titanium chainring made for an XX crank!

It’s may seem like an expensive endeavor but, if I’ve already put a ton a money into my bike, skimping now would just be ridiculous. It’d be like dining at a fancy French restaurant and not ordering wine. How much is my happiness worth? Since I’ve already tricked myself into believing that all the cash I spend on bikes and such is a good “investment” in my health, the $76 is an easy spend for me.

The SRAM XX chainring are based on a 1:1.5 ratio, with ramps and such in specific places to make them the best shifting chainrings in the world. And they are!! Suddenly changing that 1:1.5 ratio is a concern. Will it still shift crisply? Will I have to shorten the chain? Will it shift like a neglected Bio-Pace ring set? Actually…it works really well. Sure there’s probably a very slight difference that Princess-and-the-Pea riders could notice but, to me, it shifts at least as well as my previous triple crankset.

Mattais either forgot or didn’t want to countersink the crankbolt holes, and the clearance between the chain and chainring bolts is so slim it’s laughable. But hey, clearance is clearance, and that’s all that matters.

Noticing the difference between the 26t and 25t is instant, for me at least. Riding my usual trails, taking my usual lines proves to be a good test for comparison. Now…nothing is without downfalls. Just as soon as I thought I was getting used to riding a double crankset, I have to get used to it all over again. It turns out that the ratio gap gets bigger when you put a smaller little ring on your crank. Hmmm…who knew? Which means I’m now shifting from little to big, big to little noticeably more to find the gear I like. Less gear redundancy: a plus! Shifting between chainrings more often: you be the judge.

For me, I’ll take it. Having the gear I so want, I so need, I so love…is well worth an extra shift here and there.

Mattais’ Site: http://hellore.se/experimentalprototype/

Comments

ST - 03/23/11 - 10:56am

KS:
Your article just saved me $ as I was searching for a smaller chain ring set up to fit my XX 39/26 cranks. While some say this set up is enough, getting old has its disadvantages, but having the right gear set up makes all the difference, so now, from your diligence, Mattias has another 25t chain ring order to ship to the US!

zombinate - 03/23/11 - 11:44am

While it is always useful to have some nice Ti parts on the bike. Another solution would be to get a 38 tooth inner Cassette ring, and drop the 11 tooth. With the provided 26 tooth chainring upfront, it gives a 0.684 ratio.

some discussion of this solution over at MTBR:
http://forums.mtbr.com/showthread.php?t=634970

topmounter - 03/23/11 - 1:03pm

I’m no racer, but I’ve been seriously impressed with the 2×10 setup for back-country XC riding after nearly 20-years on triples. I’ve also been completely satisfied with the 26-36 low gear here in Colorado, but that’s on a light-weight, rigid 29′er. I could see myself going with the 25t on a 2×10 equipped full-suspension rig.

Speed565 - 03/23/11 - 1:21pm

Sow after spending 76$ you got a crankset that works just like a triple one. You need to shit more often and it works like a standard one. Sow I still don’t see a reasen why 2×10 is better than 3×9. It’s more expensive and still won’t be as good for amatour as 9 speed.

morpheous - 03/23/11 - 2:48pm

It gets even better when you go 1X9, drop that font der. and run a 32 / 34 /36 up front and a 11/-32 / 11-34 /or 12-36 in the back. Plenty of gear range for most XC/AM riding. (not racing) -MRP LG-1 chain guide does the trick for front chain retention. Easy.

fleche1454 - 03/23/11 - 3:51pm

@K.S. Rodland could you enlighten us more about your crankset, like what BB system you have
i know that if you have a crankset with a spider the is not molded onto the crank as you can simply get a smaller spider.
a good example of this is some of the specialized bike this season, some have the specialized crank other have the SRAM carbon crank i think its the S2200 mtn crank. The point is all those bike 26 or 29 have those ring, long term it sound like a better idea to do that then order rings from this guy as you need them.

Second, XX is a race grade group set, its meant to go on a bike with parts of matching caliber stuff like light tires, wheels, a good frame, and other race parts. I know in road racing, even if you have the best groupset on your bike, unless you have equally great other parts the drive train won’t really shine show it self. I know 29ers have a weight penalty and really good parts are not cheap for bikes but perhaps and option that might work well or is worth a try are mtn bike Q-rings from rotor. They are noticeably help me on long climbs on my road bike, i really wish i had a pair on my mtn bike but i have being in college and being a road racer i never have been able to justify them for a bike i dont ride that much.

Oded - 03/23/11 - 4:21pm

Great article, I am curious how is this different than my custom 2011 Specialized Stumpjumper FSR, where the crank 38×24 with a 11-36 cassette?

lluis - 03/23/11 - 5:33pm

carbon-ti make a 25t 80bcd too, in aluminium.
http://www.carbon-ti.com/index.php?p1=prodotti&Cat=CHMFT&Cod=CTMTBZ25I80

Epic29r - 03/23/11 - 6:09pm

listen to Morpheous – that’s game talkin….and yes Specialized has the inside setups.. myself 2×9 fsa40t/32×999

K.S. Rodland - 03/23/11 - 7:07pm

I think the difference is the bolt pattern of the spider. The XX crank on my bike has an 80/120 BCD. I think yours has a 64/104 BCD. You can make a smaller ring with the smaller 64mm bolt circle. Check the specs of your bike here: http://www.specialized.com/us/en/bc/SBCProduct.jsp?spid=53255&scid=1000&scname=Mountain

nh - 03/23/11 - 7:16pm

@morpheous – I am with you, 1×9 is the way to go. No need to think about which front ring you should be in. It forces you to attack the climbs and carry speed through the corners on descents.

Still a good article and glad to know there are custom manufacturers out there to help. One last comment, I know is introductory math but, 22/34 = 0.65 not 22×34!

joseph grimes - 03/23/11 - 9:43pm

1×10 is even better… 34 x 11/36 on a carbon hardtail 29er. its treated me well so far. jg

Dirk - 03/24/11 - 10:05am

I don’t really ride (unless you count the occasional cruiser rental at the beach) so I don’t much understand what Rodland is talking about. But, he is my nephew and the coolest guy I know, so ear up pedalers… What he’s got, get it in you!

Oscar Ekstam - 03/28/11 - 11:12am

Great to hear that the chainring worked!

And just so you other guys know, we make ANY chainring (bcd) in ANY size. A 52T for XX are as doable as a 33T for New XTR. You can also get it in Black, Green or Orange for +€10

Just give me or Mattias a mail and we´ll sort it out for you. You´ll reach me on order@hellore.se

Aaron - 12/24/12 - 10:44pm

“And the big ring…well, if you’re spinning out a 42-12, this doesn’t matter to you.”

This is pretty much a problem for me on my 26er. I run 42/28 and 11/28, and easily spin out in my top gear on gravel roads. I’m hoping for the day I can replace the 42T with a 46T, and the 28T with a 32T. Then I’ll switch to an 11/32 cassette and finally be happy. So long as my granny is a 1:1 ratio, I’m good to go.

simon - 04/05/13 - 1:16am

SRAM has a conversion kit for a 22-36T for the 2X10.

jim - 10/26/14 - 4:51am

Simon this 22-36 conversion kit for the 2×10. Does it work for the sram xx crankset?

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