Judging by the amount of traffic the release of OneUp’s 42t cassette adapter garnered, people are interested. Specifically people who want to explore the world of wide range gearing for 1x (or even 2x) drivetrains without having to shell out the cash for the upgrade to XX1 or X01. By eliminating one of the gears from a standard 11-36 10 speed cassette, OneUp made room for their 7075-T6 aluminum 42t sprocket – effectively turning the cassette in an 11-42. Costing less than other options, the OneUp sprocket looks like a promising alternative to get the lower gearing you crave, but how will it stack up?
Install notes, actual weights, and more, after the break! Updated with first impressions after the jump!
As covered in our first post, the OneUp ring has 12 shift ramps machined into the surface to help the chain jump from the 36 to the 42t. Laser engraving on the ring tells you which side to place the OneUp spacer, so it’s pretty hard to mess it up.
As for the weight, the 42t sprocket itself comes in at 71g with an additional 2g for the needed spacer. Subtract 20g for the 17t cog and spacer and you get an added 53g for a total cassette weight of 390g with a Shimano XT 771 10 speed cassette.
All mounted up the cassette looks pretty normal (with the exception of the obvious green ring) – it’s only when you look closer you may notice the missing 17t. Installation was extremely straight forward, just follow the instructions for removing the 17t cog and a spacer, and make sure to position the OneUp spacer according to the directions printed right on the sprocket. Mount the rest of the cassette as normal, and you’re done.
To prevent the sprocket from digging into freehub bodies, the OneUp is built with wide spline tabs – quite a bit wider than the steel 17t cog that came off.
When it came to adjusting the derailleur, I’m honestly surprised at how easy it was. Somehow I expected it to be more involved to get it to shift properly, but I was happily mistaken. After adding the necessary two chain links to accommodate the bigger gear, the only other step was to adjust the b-tension screw. Realistically, it was more like bottoming out the b-tension screw, but there was just enough adjustment to clear the big teeth without issue on my Pugsley.
I’ll be testing the ring out on a few bikes, but I’m especially excited to try this out on the Pugsley. Ditching the front derailleur on my fatbike was great at first offering no chance of the chain rubbing on the tire, fewer parts to freeze up, and lighter weight, but after I started doing more techy rock crawling type riding, a lower gear would be nice. I’m hoping this is the little bit extra I need to go along with the 30t WTC front chainring.
Certain frames may require some of the additional steps outlined on OneUp’s Site, since it is pretty close. I would suggest lengthening the chain first before trying to shift into the biggest gear due to the fact that if your chain is too short, the derailleur cage will catch on the sprocket and not function properly.
The $100 sprockets will be shipping out at the start of 2014 if you get your orders in now. When asked about the $100 pricetag, OneUp noted that as the part size goes up, so does the cost of CNC machining. Bigger billets are needed with more machining time needed to mill them down to spec.
We’ll report back this afternoon with first ride impressions!
First Impressions:
We have had some awesome fatbiking conditions lately, and with a few inches of fresh powder on top of the old snow it was a perfect opportunity to get out and test the OneUp cassette adapter. Riding a similar path to one ridden on Saturday, I can definitively say it was better today with the extra gearing range. The added grunt of the 42t made it possible to stay seated for traction, and power out of some hairy situations like large rocks coated in ice, covered in snow. The absence of the 17t was really only noted when you really thought about it, and the two times I noticed it during the two hour ride I was on the road. Testing it on a mountain bike is next, but for the Pugsley and fatbikes in general, I will gladly give up the 17t for the extra low end. When combined with the 30t WTC chainring up front, the 11-42 spread is just about all I need from riding on clear roads to picking my way through a river bed.
It turns out that with the b-tension screw bottomed out the shifting is close, but not perfect. Shifting up to the 42t was uneventful 60-70% of the time, though every once in a while there was a little whirring as the chain and derailleur hesitated a moment before shifting. Taking OneUp’s advice, I removed the plastic tab inserted in the derailleur under the B-tension screw. Remove the screw completely from the derailleur and the tab pops out easy with a pick or similar tool (I would put it aside for safe keeping in case you need it in the future!). Just in case the plastic tab acts as a nylock fastener for the B screw, I dabbed a tiny bit of blue Loctite on the screw before reinserting it into the derailleur without the plastic tab. With the tab gone, there was plenty of extra room to dial in the B-tension that little bit more, and it now shifts perfectly all the time, every time. OneUp points out that if you still need more B-tension after removing the plastic piece, you can actually install the B-tension screw backwards which will push the derailleur out even farther.
All said and done, the shifting performance of the OneUp system is great – so much so that once you have it set up properly you will have a hard time noticing it while you pedal. If you’re looking for an alternative to XX1 for a wide range of gearing, the OneUp is definitely worth a try.
Drivetrain Setup:
- e*thirteen XCX+ fatbike crank
- WTC 30t 104 BCD chainring
- Shimano M771 10 speed 11-36 cassette
- Shimano CN-HG94 XT 10 speed chain
- Shimano XT M786 Shadow Plus Long Cage Rear Derailleur
- OneUp 42T cassette adapter
- Shimano M780 10 speed shifter
PS – for those wondering, the full 10 speed cassette plus the OneUp adapter does NOT fit on an 11 speed road freehub body. It’s close, but you can’t get the cassette lockring to engage the threads.
