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NSMB Tests SRAM XX1 On the Trail

Aug. 29, 2012, 10:35 a.m.
Posts: 707
Joined: Sept. 15, 2011

This is something I'd also like to know.

I've been riding a 2x10 this season and I am not in love. With the 26-38 front and 11-36 rear. The 38 is too large for local trail riding so I end up in the 26 for the bulk of my riding. Somewhere like Bend or Sun Valley and this wouldn't be an issue.

I like the ability to make large jumps with one shift in the front, I've never had problems with front mech being some evil thing I hate. I've had other front issues of keeping the chain on, but it's not shifting based.

I have the same setup as you. I have been using the 38 a lot more lately now that I am confident that I have the chain length to run all the way to 38-36 if I need to (chain line be buggered). Not saying I do that a lot, but I will routinely go to the third largest cog on the rear if there is a short uphill section to clear. I like the reduced chain slap/chain drop of the 38t plus I seem to hold momentum better. Plus, my bike is possibly a bit plusher in the 38 than the 26 due to suspension geometry (but probably more due to perception).

I generally find (on Fromme anyway) 26 for the climb, 38 as soon as I hit the trail.

Cheers Ben

Aug. 29, 2012, 10:44 a.m.
Posts: 8935
Joined: Dec. 23, 2005

I have the same setup as you. I have been using the 38 a lot more lately now that I am confident that I have the chain length to run all the way to 38-36 if I need to (chain line be buggered). Not saying I do that a lot, but I will routinely go to the third largest cog on the rear if there is a short uphill section to clear. I like the reduced chain slap/chain drop of the 38t plus I seem to hold momentum better. Plus, my bike is possibly a bit plusher in the 38 than the 26 due to suspension geometry (but probably more due to perception).

I generally find (on Fromme anyway) 26 for the climb, 38 as soon as I hit the trail.

Cheers Ben

Sure 38 is okay for the Fromme's mostly down stuff, not many mid trail short steep punch climbs, I find when riding in Whistler west side trails where you have more varied terrain that it just doesn't work. I've blown two chains because I was running them long enough to get the the 38-36, when in lower gears there was soo much chain slap that I've twisted links. I now run a shorter chain so 38-36 isn't an option.

I have a Shadow+ on it's way that will help with the chain slap, but the ratio's don't change. I'll go to a 36t front that will give it a bit more use, but a 34t would be better. Too bad nobody makes a 34t that goes on a dedicated 2x10 crank. I am tempted to put my 3x cranks on it and run 26-34-bash.

Aug. 29, 2012, 10:46 a.m.
Posts: 707
Joined: Sept. 15, 2011

Sure 38 is okay for the Fromme's mostly down stuff, not many mid trail short steep punch climbs, I find when riding in Whistler west side trails where you have more varied terrain that it just doesn't work. I've blown two chains because I was running them long enough to get the the 38-36, when in lower gears there was soo much chain slap that I've twisted links. I now run a shorter chain so 38-36 isn't an option.

I have a Shadow+ on it's way that will help with the chain slap, but the ratio's don't change. I'll go to a 36t front that will give it a bit more use, but a 34t would be better. Too bad nobody makes a 34t that goes on a dedicated 2x10 crank. I am tempted to put my 3x cranks on it and run 26-34-bash.

True story, Whistler has me in the 28 as soon as it turns uphill.

Cheers Ben

Aug. 29, 2012, 12:39 p.m.
Posts: 36
Joined: March 9, 2009

I'm in, I'll make my own bash guard out of the 10 old ones I have kicking around from changing drivetrains

Aug. 29, 2012, 12:52 p.m.
Posts: 4300
Joined: June 24, 2010

For all that are talking about XX1 not providing a short enough granny, the 28 tooth front ring option and 42 rear gives the same 0.667:1 gear ratio as a 24 up front with 36 out back. Sure, that's not quite as short as a 22 tooth granny, but how many people are actually running a 22 tooth granny with a 36 tooth (10 speed) rear? It's becoming harder to find a crankset that comes stock with a 22, so most with that size granny will actually have a 9 speed 34. Of course the compromise of the 28 tooth up front comes at a 2.8:1 top gear, but personally I don't use the top gears on the 36 very often so I think it would be feasible.

flickr

Aug. 29, 2012, 1:21 p.m.
Posts: 2009
Joined: July 19, 2003

For all that are talking about XX1 not providing a short enough granny, the 28 tooth front ring option and 42 rear gives the same 0.667:1 gear ratio as a 24 up front with 36 out back. Sure, that's not quite as short as a 22 tooth granny, but how many people are actually running a 22 tooth granny with a 36 tooth (10 speed) rear? It's becoming harder to find a crankset that comes stock with a 22, so most with that size granny will actually have a 9 speed 34. Of course the compromise of the 28 tooth up front comes at a 2.8:1 top gear, but personally I don't use the top gears on the 36 very often so I think it would be feasible.

wow did you just bust out math. I want more hearsay and anecdotal evidence. Adam Craig raced a 2:1 gear ratio on a single speed in a world cup race, there for all you need is one gear. har

Just a speculative fiction. No cause for alarm.

Aug. 29, 2012, 1:32 p.m.
Posts: 4300
Joined: June 24, 2010

Unfortunately I can't help but calculate gear ratios when new options are presented. I've spent a lot of time riding single speeds, doing long distance on fixed bikes, and really long days on the road bike. Nerding the gears is a good way for me to pass time and miles.

flickr

Aug. 29, 2012, 2:38 p.m.
Posts: 5731
Joined: June 24, 2003

For all that are talking about XX1 not providing a short enough granny, the 28 tooth front ring option and 42 rear gives the same 0.667:1 gear ratio as a 24 up front with 36 out back. Sure, that's not quite as short as a 22 tooth granny, but how many people are actually running a 22 tooth granny with a 36 tooth (10 speed) rear? It's becoming harder to find a crankset that comes stock with a 22, so most with that size granny will actually have a 9 speed 34. Of course the compromise of the 28 tooth up front comes at a 2.8:1 top gear, but personally I don't use the top gears on the 36 very often so I think it would be feasible.

True but you will give up a bit of top end over a 24 X 36 c ring set up which on my Nomad would be fine. Less acceptable on my 29er hardtail but I would not be compromised very often.

Debate? Bikes are made for riding not pushing.

Aug. 30, 2012, 4:53 p.m.
Posts: 0
Joined: Dec. 2, 2011

@Clarklewis
I don't ever dump the front ring when I come upon sudden climbs. Instead I keep power nice and even as I slice gear by gear. Sudden dumping into the granny ring only causes a massive change in cadence and subsequent lose of momentum.

Aug. 30, 2012, 7:15 p.m.
Posts: 1393
Joined: Aug. 13, 2009

@Clarklewis
I don't ever dump the front ring when I come upon sudden climbs. Instead I keep power nice and even as I slice gear by gear. Sudden dumping into the granny ring only causes a massive change in cadence and subsequent lose of momentum.

*loss

Aug. 30, 2012, 10:06 p.m.
Posts: 0
Joined: Aug. 30, 2012

Second photo has the caption "just five parts make up the complete XX1 drivetrain"
Not true as you still need the proprietary cassette driver.

Sept. 1, 2012, 1:08 p.m.
Posts: 21
Joined: Nov. 20, 2002

1X11 is good but I think only for XC where you could change the front ring depending on the course. For All mountain etc… a gear box is the future, this is getting closer http://pinion.eu/en

http://www.epiccyclist.com/

Sept. 1, 2012, 2:49 p.m.
Posts: 5731
Joined: June 24, 2003

http://pinion.eu/wp-content/themes/pinion/content/images/precision-p118-english.jpg

Yikes! No gear friction there. Or complexity. Or weight.

Debate? Bikes are made for riding not pushing.

Sept. 1, 2012, 3:14 p.m.
Posts: 21
Joined: Nov. 20, 2002

http://pinion.eu/wp-content/themes/pinion/content/images/precision-p118-english.jpg

Yikes! No gear friction there. Or complexity. Or weight.

agreed… but be patient, just a matter of time before some of those issues are sorted out(up to a point tho). It's the best design I have seen so far. Very similar to the rohloff but in a better spot and those last for ever.

http://www.epiccyclist.com/

Sept. 2, 2012, 10:40 a.m.
Posts: 707
Joined: Sept. 15, 2011

agreed… but be patient, just a matter of time before some of those issues are sorted out(up to a point tho). It's the best design I have seen so far. Very similar to the rohloff but in a better spot and those last for ever.

Maybe, maybe not. It's not the design that's an issue, it's the inherent efficiency of gearbox versus chain drive. It is a big deal when you only have a fraction of a horsepower to work with. IMO the maintenance issue and costs with the current system are no big deal in any case. Simple, light, efficient - an engineers wet dream.
Cheers Ben

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