One-up 40 tooth sprocket and RAD cage.

19 10 2014

When I was looking at doing the Highland Trail Race earlier this year, I was slightly concerned that my usual 1×10 set up would not have a low enough gear to cope with the combination of very tired legs, steep hills and a loaded bike. I looked at using a 30 tooth chainring, but felt this would diminish the gear range detrimentally.

At that point I became aware of the release of the RAD cage, by One-up components. The purpose of this is simple: it changes the way the upper jockey wheel moves in relationship to the rear freehub cluster. Why? you can adjust a traditional derailleur to cover a broader range of rear sprockets, primarily by increasing B tension, this creates enough clearance for a 40 or even 42 tooth sprocket. However, this compromises the jockey wheel’s tracking of the sprockets, particularly in the higher gears (smaller sprockets). In essence, shifting suffers as the upper jockey wheel is far in excess of the suggested 6-8mm from the sprocket.

The RAD cage is well made and following the video instructions for installation makes the process extremely easy.

A few months ago, I fitted a 40 tooth large sprocket and the provided 16 tooth sprocket that replaces the 15 and the 17 tooth sprockets in the original cluster (you must remove one in order to make room on the freehub body for the extra 40 tooth sprocket). I use a Wolftooth 32 tooth chainring, with an XT donor cluster and XT rear mid-cage derailleur. I decided on the 40 tooth rather than the 42 because I felt this would give the derailleur a little less of a hard time and it is also the same range as the new XTR that I am quite keen to use in the future.

I have a few hundred miles on the system now using the provided One-up 16 tooth replacement sprocket and then an aftermarket XT 10 speed 16 tooth sprocket*. The gear range has changed from 11-13-15-17-19-21-24-28-32-36 to 11-13-16-19-21-24-28-32-36-40. Unfortunately, the 15-17-19 area is where I spend a lot of time and I was concerned I would feel I was not in the right gear too often. It is true that I do feel the increased jump between ratios, but not badly enough to take away from the huge boon the 32-40 ratio is. You can climb walls, even loaded, with this gear ratio.

Shifting: the shifting has been a mixed bag. The ramps on the provided 16 tooth ring seem (to me at least) to be in an unusual orientation. The part has 2 fitting positions: one for SRAM and one for Shimano. I initially used the Shimano position and noticed a lag of around a second of chirping before an up shift was achieved. There was also a lag on the down shift. When I fitted the part, it was clear the SRAM position was much closer to keep the ramps on the sprockets in line, but I decided to follow the instructions to the letter. On refitting in the SRAM orientation, things improved but there was still a lag that bugged me.

I then fitted a *Shimano 16 tooth sprocket and with this, although not exactly in line, the ramps were really closely aligned indeed. Shifting quality is now almost at original ‘Shimano perfection’ levels. I think the detailed tooth profiling aids up shifts to higher gears and the ramps being in line helps the down shifts. Don’t get me wrong, the supplied One-up 16 tooth is good, but Shimano carry a big stick when it comes to shifting performance. This is something I would recommend if you go for this system with a Shimano set up – I cannot comment on the SRAM performance.

Longevity: you *can* see wear on the 40 tooth sprocket (it is anodised black aluminium as opposed to the steel of the original Shimano set up) but there has been no drop in performance.

All in all, I am extremely happy with this set up. Things I would like to try: a short cage RAD cage for the Saint derailleurs I love. I have no idea if this would provide enough chain gathering to let the system work, but I can dream.

All in all, I would say this system merits 8 out of 10. If longevity remains good as we come into winter that would be 9/10. Improved 16 tooth sprocket would give it a near perfect score: as a hop-up kit to provide increased gear range, with the accepted change in the jumps between ratios, it does exactly what you want it to do and it does it very well indeed.




4 responses

20 10 2014

Interesting thanks, my girlfriend is using a 1×10 setup with the hope expander, she hates the gap in the gears around the missing cog, she also has sram 1 x 11 on her other bike that she likes, why did you not go that route?

20 10 2014

well, the short answer is i don’t really like sram stuff… ;-)~

21 10 2014

Lol, fair enough, happy trails.

20 10 2014

i’m going to be going this route on the krampus for bikepacking… i have a 30t wolf tooth front on order. will likely go the 40t rear when it happens. i’m running sram cassettes, so i’ll have to see what i end up doing. looking at the wofltooth cogs they have a universal SH and SR 16t. i’ll have to see how it goes. running this on the stock SLX derailer and Zee crank. thanks for the info!

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