Friday, October 16, 2009

This one goes to 11

Or, well, 7. But still, not bad. Today I put an XT cassette on the lathe, and when I was done, I had something freakin' awesome - a 1x7 drivetrain. That's right. 7 gears on a singlespeed hub - 15-34 (you could do 13 or 14-34 too if you wanted to). I rode Doudy Draw and Springbrook on the setup this morning and it works really, really well. Psyched to be out on the bike, even if I was still coughing a bit.

For those who are curious, I'm on the geeking-out binge for 3 reasons:
-I sold my singlespeed to Chris, so this is my only bike right now.
-The only decent rear wheel (that will work tubeless) I own currently is this one, and it's got a singlespeed hub.
-I've been too sick to ride or work and had nothing better to do than think of stupid bike ideas.
Other notes:
-With the SRAM derailleur, a longer limit screw and some derailleur cage grinding is necessary to get all the gears to work. I hear that this isn't a problem with Shimano derailleurs, but I don't have one of those.
-Yes, I'll be happy to modify a cassette for you if you want. For a reasonable fee. Just drop me a line.

9 comments:

tristan said...

Hi Walt - this mod also works on the Pro2 SS hubs. With the Pro2 there is enough material on the freehub body that you can remove about 2mm from it and then you don't need to modify the cassette.


http://picasaweb.google.com/wheelworks.co.nz/WheelworksNZMTBRMagazinePro2HubsZTRArchRims1705grams#
and
http://picasaweb.google.com/wheelworks.co.nz/PolishedPro2HubCentersAndModifiedCassetteBody#

Also - putting an axle spacer on the SRAM rear derailleur bolt will give you an extra 2mm and you shouldn't need to do any further mods to the derailleur.

Bikewright said...

I have waiting for somebody to post some information about this subject.

Thanks for adding the links

Rob Young said...

Awesome. :)

I think there is a huge market for stuff like this, I think if someone made prehacked drivetrains and XT-like (and priced) SS cassette hubs to go along with it, it'd sell like wildfire.

I'm using a SRAM PG 970 cassette on my single speed, which is held together by bolts. I *think* you could do the same thing you did here by taking out some cogs and buying appropriately shorter bolts.

tristan said...

@Rob - you can certainly remove the bolts which hold the cassette together. You don't need to replace them with anything as they don't really do much other than hold the cassette together when it's off the wheel. Most SS hubs use a steel freehub body which will no have problems with the single cogs digging into the freehub. The DT Swiss uses an aluminum freehub body though so it would be best to stick with a spidered XT-style cassette.

I've been running 2x7 for a few years: 28/38 on the front and 13/32 rear. With a 9 speed chain there is much less cross-chaining and the drivetrain lasts a lot longer, plus you get rid of gears you don't use.

The rear wheel can also be built much stiffer and/or lighter because of the wider flange spacing of the SS hubs.

MikeQ said...

for a reasonable fee can you modify my 6-speed townie block into a Ti 12-speed?

Doug Brummett said...

Cool stuff Walt. Might want to check compatibility with a newer XT cassette. My latest one has some pins on the back side to keep the chain from dropping behind it too deep. They might interfere with spokes with this mod.

tristan said...

Doug, only one of the pins on the newer cassette interfered with the spokes on the Pro2 hub after I took about 2mm off the back of the freehub body. With the DT Swiss hub they shouldn't interfere because the center-flange measurement is a bit narrower and the flange diameter a bit smaller.

Ed said...

I am running a 1x8 on my DT Swiss single speed rear hub. Removed all of the 2+ mm flange on the back of a 36,32,28 Shimano SLX spider and then mixed and matched with other SLX cassette cogs, now running 36,32,28,24,21,18,15,13. Can save a mm by reducing diameter of Shimano cassette lockring so that it tightens inside the recess of 13t or 12t cog. Some mods to the short cage Sram XO type 2 RD.

Works flawlessly and I get a symetrical whheelbuild :)

Ed said...

I am running a 1x8 on my DT Swiss single speed rear hub. Removed all of the 2+ mm flange on the back of a 36,32,28 Shimano SLX spider and then mixed and matched with other SLX cassette cogs, now running 36,32,28,24,21,18,15,13. Can save a mm by reducing diameter of Shimano cassette lockring so that it tightens inside the recess of 13t or 12t cog. Some mods to the short cage Sram XO type 2 RD.

Works flawlessly and I get a symetrical whheelbuild :)