A question for your MTB people out there

[hesh0925]

Howdy! I have a question to ask regarding MTB drivetrains. I've searched some website called Google but I keep getting conflicting answers. So I come to you fine folk.

So as for the question, it's about converting to a 1x drivetrain. I am planning on building up a XC MTB soon and want to go with either 1x11 or 1x10. My plan is to buy either an SLX or XT groupset and just convert it over to 1x. But I'm not 100% sure if I should get a 2x or 3x crank. I know the chainline differs when converting either one, so which would you say is the best option?

Thanks in advance. :banana:

[CMiller]

I believe a triple with just the middle ring brings the best chainline. Just plop off the granny and big ring, and put smaller chainring bolts for the middle ring. If you throw a bashguard on, then you don't need to buy new bolts!

[CMiller]

Also, I wouldn't buy a whole groupset. You won't need the front derailleur or left shifter. Try to find a source where you could order the right side individually. Also, clutch derailleurs are a must!

[ofcounsel]

Also, I wouldn't buy a whole groupset. You won't need the front derailleur or left shifter. Try to find a source where you could order the right side individually. Also, clutch derailleurs are a must!

Agreed. Consider skipping Shimano cranks and consider buying a Sram X9/X0 crankset. You can get the X9's in particular pretty cheap. Each are nice because you can dispense with the spider and use a direct mount chainring. Similarly, newer Race face Turbine cranksets are also nice, relatively inexpensive and use direct mount chainrings as well. Also, this is just me and I'm no bike mechanic, but with 1x, I don't spend too much time worrying about chainlines. I don't find it as critical, because (1) no front derailleur rub, (ii) one ends up shifting from low to high so often, and (iii) MTB chains wear quicker due to all the dirt and grime one picks up on the trail. I replace chains around every 600 miles.

Edit: Here's an inexpensive SRAM X1 crankset with chainring: http://www.backcountry.com/sram-x1-1000-gxp-crankset?ti=U2VhcmNoIFJlc3VsdHM6Z3hwIGNyYW5rc2V0Oj E6NzpneHAgY3JhbmtzZXQ&skid=SRM001Z-BK-S175MM

Al

[CMiller]

And if you're building up from scratch, Deore hydraulic are incredible, and incredibly priced.

[ofcounsel]

And if you're building up from scratch, Deore hydraulic are incredible, and incredibly priced.

Yep, super value. XT's as well. I currently run XT brakes on two of my bikes and SRAM Guide RSC's on a 3rd bike. RSC's are my new favs, but significantly more expensive than the XT's and the XT's are great!!!

[A1CKot]

The new XT-8000 stuff is available in 1X11, 2X11 and 3X11. Its also way cheaper than Sram X1 and will work with existing 10 speed mountain hubs.

[ofcounsel]

The new XT-8000 stuff is available in 1X11, 2X11 and 3X11. Its also way cheaper than Sram X1 and will work with existing 10 speed mountain hubs.

Yep, each of the components on the XT-8000 stuff is reasonably priced and cheaper than Sram X1, except for the cranks. And yep, XT 11 speed cassettes work with existing 10 speed mountain hubs. But this means that each of the cassettes have to use 11 tooth big gears, instead of the 10T big gear that sram uses. If you're a stronger, fitter rider and are using 32T front chainring or better, then the Shimano 1X is ok, as you'll likely still have enough top end with 32x11 gearing. If you're less strong, like I am, I tend to use either a 30T or a 28T front chainring. a 30x11 combo is boarderline, and I can spin it out on flats, 2% slight downhills. 28x11 is not enough top end on longer slight downhills.

[gdw]

"I replace chains around every 600 miles."

Ouch, that's less than a month's worth of use and you're not riding in wet conditions.

[ofcounsel]

"I replace chains around every 600 miles."

Ouch, that's less than a month's worth of use and you're not riding in wet conditions.

Hahaha! I'd love it if it was. MTB riding, at least for me and the terrain I ride in, it takes a lot more time to cover ground. It takes me a lot more time to rack up MTB miles v. Road miles.

My average MTB ride is 11 to 15 miles. I average 3 MTB rides a week. Once or twice a month, I might put in a 20-25 mile MTB ride. And then I split the mileage between 3 MTB's. So 600 miles on an MTB is several months of riding. The chain stretch at 600 miles is still usually within the outer limits of proper spec, but with SRAM 1x systems, the cassettes are expensive. So I'd rather change the chains quicker and make the cassettes last longer. Once the chains get too worn, they tend to really beat up the 42T granny sprocket to the point that it won't shift well if you wait too long to swap the chain out. And at that point, you're spending $250+ on a new cassette. So 600 mile chain replacement for SRAM 1X is good insurance IMHO.

And out here, dry conditions are just as bad as wet for chain durability. We have so much dirt/sand on our trails as a result of the drought... Equipment gets really dirty real quick.

[tedbarbeau]

Agreed with the posts above. Go with the new XT-8000.

[Mikej]

Don't get hung up on chain line - its not what you think. The center of bb to "chain line" is offset by the machining of the chain wheels. The spider of a 1x 2x or 3x are all the same, the ring is what is different. I run a 2x11 XTR trail crank with 36/26 and the XTR 11 SPD 11-40 cassette and find it perfect for Wisconsin racing. I could buy an XTR 1X or a narrow wide after market ring and install it on same cranks and remove front der. for a 1x.

[hesh0925]

Thank you all for your replies! I think the XT M8000 1x is my best bet. I got offered one but sadly the exchange rate is so bad that I had to pass (I'm in Canada).

My friend recently installed the Race Face Turbine so I was looking to that. The only thing that kinda threw me off was the bb. Anyways, I think I've found what I wanted so cheers!