OneUp 45T Sprocket
I understand that the market for this drivetrain hop up, from Squamish locals OneUp, is going to be pretty small right now. There aren’t a bunch of folks rocking the new XTR or XT setups on their bikes just yet, but as SRAM and Shimano sort out the world of 1x drivetrains, the OneUp 45 tooth sprocket combined with a Shimano 11-spd cassette could offer a prime set of ratios in the 11-speed world. NOTE – the 45 is only compatible with the 11-40 XT cassette and not with the 11-42.
When Shimano finally released their reaction to the SRAM XX1 drivetrain, in the form of the new XTR, there was mass derision from the internet hoards. The sticking point? The 40 tooth largest sprocket. Before fitting the OneUp upgrades I had plenty of time riding the XTR setup. As you would expect, crisp smooth shifts and a sense of solidity massages the digits as you shift up and down the cassette. I had a 32 tooth chainring paired with the 11-40 tooth cassette, which despite a great spread of gears, didn’t quite give me the climbing gear I needed without my kneecaps wanting to pack their bags and head to Hawaii.
The aluminum 45 tooth sprocket is huge; it dwarfs the 32 tooth chainring OneUp sent to use with the sprocket. Also in a departure for OneUp, it is anodized an XTR compatible grey. Folks that have the cash for XTR are obviously a little more concerned about aesthetics and a bright green sprocket just wouldn’t do. OneUp also supplies a hardened steel 18T sprocket which replaces the 17 and 19 tooth stock XTR versions. For weight weenies this set up adds about 65 grams, so get your drill and ventilate your cranks to get that back(note – not actually recommended).
The addition of the 45 tooth sprocket requires little change to the mechanics of the bike. The new 11 speed XTR rear derailleur requires a minor tweak to the B-tension to clear the larger sprocket, but once that’s taken care of chain wrap is very good.
The dinner plate-sized cog doesn’t compromise the silky Shimano shifting and the ratios are nicely spaced with no awkward jumps. The combination of the 45 tooth sprocket with the 32 tooth chainring gave me the ratio that I needed for everything but the steepest climbs. I think that if I lived in Whistler I’d switch to a 30 to get up the steeper grunts, but for most of the climbs I do the 32 did the job.
There was a touch more drive train noise when using the 45 tooth sprocket, maybe due to the chain line on the bike I was riding. It wasn’t much more than a slight increase and interestingly, it was more noticeable with the stock Shimano 1x chainring than the OneUp narrow-wide ring. Perhaps those taller profile teeth on the Shimano ring make the difference?
If you are one of the fortunate few to be riding the new 1x XT or XTR then the OneUp 45 tooth sprocket is a worthy upgrade. Those of you who aren’t looking for a lower granny gear can benefit from a 12.5% increase in range, allowing you to fit a larger chainring. I was looking for that climbing gear and the upgrade delivered that without any downsides.
OneUp’s 45 for XTR can be ordered directly from their web site. It’s $104.99 for Canadians and $90 US for the rest of the world – with free shipping. More info here.
Anyone lucky enough to be rocking the new XTR setup?