OneUp 42 Tooth Cog: Hands On

My knees just breathed a sigh of relief. My OneUp Components 42 tooth cog arrived and is now mounted up on my bike. Having jumped on the 1x trend back in the summer I have been working with the 30 tooth Wolftooth chainring matched with my Shimano 11 to 36 tooth cassette.

In most scenarios the ratios on offer work very well for me, however there are those few climbs where having a slightly lower gear would be nice. It would allow me to finesse up a climb rather than grunt. So without ripping out my Shimano drive train and dropping some serious coin on XX1 when I heard about the OneUp Components 42 tooth option my hand shot up first, especially when you consider that the OneUp option is $100 and not $1400+.

The cog is machined out of aluminum, with shift ramps machined into the tooth profile. The cog has a wide interface with the freehub which makes me hopeful that it won’t chew up the carrier like some individual steel cogs can. It also has some raised nubs, which initially look arbitrary but once installed actually butt up to the 36 tooth cog to provide some stiffness.

Fitting the cog is really very quick. It actually took my longer to find my chain whip than it did to get this fitted and set up. Firstly my current set up is a Shimano 11-36 tooth cassette, XT rear derailleur and a Wolf Tooth 30 tooth front chainring all mounted up to my Santa Cruz Tallboy LTC.

Tighten up the lock ring and that is it, the sprocket is installed. With the larger range of gears I needed to add a couple of links to the chain. Luckily I had some still after I had recently installed my new chain.
Before you reinstall the wheel make sure to adjust the B-tension screw. This is important to ensure that the cage of the derailleur will clear the larger sprocket. On some frames with Shimano rear derailleur’s the B-tension screw may not be long enough to get the cage to clear the cog, which was the case on my bike. After consulting the instructions on the OneUp website I followed the suggested remedy of removing the B-screw, removing the plastic washer that remains attached to the screw and reinstalling the screw without this washer.  There are good instructions on the OneUp Website to help you get it working well with your specific setup.

Now reinstall the wheel and away you go. Check the shifting, particularly between the 36 and 42 tooth cogs and check the high limit screw. Mine was just fine and the bike shifted fine in the stand. The whole installation is quite straight forward and takes maybe 20 minutes to complete (after finding your chain whip).

To give the new setup a good workout I took the bike for a loop on Seymour, one that has lots of shifting. First impressions are good. The shift up to the 42 tooth cog is surprisingly crisp, especially considering that the derailleur was never designed to shift to such a large cog. Given that the shift up is usually one that is done under pressure, none of my shifts up to the OneUp cog were met with any more noise or hesitation than any other shift around the cassette. The jump lower down the cassette from the 15 to 19 tooth cog is noticeable. To be honest I didn’t use those gears once I was into the trail system, so in normal riding it isn’t an issue. For a lot of the riding around here you are typically stuck in the top 2/3rds of your ratios. If you are someone that rides in an area where you use every ratio on your cassette this may be an issue. There is a lot of discussion on the forums that there is a way to bridge this gap with some cogs from other cassettes if it bothers you enough.

So far the OneUp seems like a good solution for those of us that want to run a single ring up front but still want a gear to climb in without blowing our knees out. There are some things that I want to keep an eye on over the next few months. I’m intrigued to see how the cog wears in the wintery conditions and if the single cog in such a high torque situation causes any damage to the freehub body. I’m also interested to see how my Shimano XT rear derailleur stands up to being stretched over such a big range.

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OneUp Components has been nice enough to extend the $15 discount for NSMB readers mentioned in the initial article. Simply use the discount “nsmboneup” and it is good until midnight Saturday, January 25th. Pretty sweet!