Posted on June 19, 2013 by Bryan Ball

By BRYAN J. BALL

Managing Editor

Recumbent riders are almost never happy with the stock gearing on their bikes. This is doubly true for trike riders. Some of this is because a lot of us have an inherent desire to tinker, but the main reason is that many recumbent manufacturers send their bikes out into the world with gearing that is just too high for most riders. There are plenty of expensive and complicated solutions out there to get you geared down for that last big hill. However, I’ve recently stumbled upon a rather simple and inexpensive one.

The MTB Tools 41 tooth (41T) cog is something that shouldn’t work. Before I even start this review, I’ll say that SRAM and Shimano both firmly claim that this will simply not work with any of their derailleurs and you can toss your warrantee out the window if you use it. To this I say the same thing that my daughter says if I tell her that she’s putting too much syrup on her pancakes… Whatevs.

SRAM actually inspired this product in the first place. Last year, the company introduced the XX1 system. This is a single-chainring drivetrain with an 11-42 rear cassette. It’s aimed at mountain bike racers who don’t need or want a front derailleur. When the rest of the cycling world saw the monstrous rear cassette, some of them became jealous. Unfortunately, the XX1 requires a special chain and therefore won’t work with any available double or triple cranksets.

MTB Tools owner, Chris Laundrie, didn’t take no for an answer and got to tinkering. He and a few others have found that many long cage mountain derailleurs do, in fact, work with cogs larger than 36T. This is especially true with newer SRAM units. Chris is an experienced machinist who makes all matter of bike tools, so he busted out the machine tools and came up with this simple conversion kit that will work with existing bicycle gearing systems.

All I needed to purchase from the MTB Tools eBay shop was the $36.99 stainless steel 41T cog and an oversized cassette lockring for $12.99 . Depending on the cassette you’re switching over, you may need to buy a 12T or 13T cog from MTB Tools also. You can use either a nine or ten-speed cassette that goes up to 34T or 36T but I’d recommend the latter. I already had a SRAM PG-1050 ten-speed 11-36 cassette around so I didn’t need to buy one of those.

The overall quality of the MTB Tools cog is pretty good but not excellent. There were some small burrs on the teeth and the finish is a bit rough. However, this is a consumable part that will soon be covered in chain oil and the burrs all wore off within a ride or two, so that’s not a major concern. The more shocking thing was that it weighs a whopping 150 grams. That may not sound like much but it’s a third of a pound! The entire cassette only weighed 330 grams before I messed with it.

Installation was initially quite easy. I removed the stock ten-speed cassette, tossed aside the 11T small cog and the original lock ring, put the MTB Tools cog on the wheel and reinstalled the cassette with the new larger lock ring. This now gave me a 12-41 cassette.

Getting it to shift properly did take some effort. First of all, I had to buy more chain. If you’re smarter than me and kept the extra chain that probably came with your bike or trike, you won’t need to do this. Second came A LOT of derailleur fiddling. I used a 2011 SRAM X.0 with a SRAM TT500 bar-end shifter for this and I hear that the 2012 and newer SRAM parts with the standard grip shifters work a lot better. I basically found that I could take the top limit screw out and throw it away if I wanted. This definitely maxed out the derailleur’s travel. I also found that I had to run the cable tension a bit higher than I normally would.

I used the MTB Tools cog on an HPVelotechnik Scorpion fs 26. It was a good choice because it’s a bit heavy and with the large rear wheel, it could use the lower gearing. Moving from the 36T to the 41T lowered my lowest gear from 20.7” down to 18.2”. Since the 11T was discarded in favor of the 12T, the high gear dropped from 117.6” to 107.8”.

Contrary to SRAM’s warnings, the rear derailleur did handle the load. If I was in the middle ring and under a lot of power, there was a bit of clattering when trying to shift from the 36T into the 41T but the chain always did make the jump eventually. This is due to the rather large jump and the fact that the MTB Tools cog isn’t ramped like the stock cogs. When I was in the granny ring, the chain would engage the 41T every time just as well as it did on the stock cogs. Again, a newer SRAM derailleur and grip shifter may have handled this even better.

I also noticed that the 12T high gear made just a small amount of noise if I was in the middle chainring but was silent if I engaged it in the big ring. I attribute this to chain tension. That 41T requires a lot of chain and you will find some slack in combos that you probably shouldn’t be using anyway. In the smallest front chainring, only the largest four or five cogs on the rear cassette are usable. This will almost certainly not be an issue for people who are experienced with any conventional triple-chainring derailleur-based drivetrain and have learned how to use it properly.

As I’ve said above, it did take some tweaking but once I got everything up and running, I have to say that I was pretty impressed. The MTB Tools cog allowed me to stay in the middle ring for almost all of my daily riding where I would usually have to dip into the granny for a few local hills. When I got off the usual routes and went for the big hills that will always require the granny ring, those extra couple of gear inches were a godsend.

I’m going to leave the MTB Tools cog on the trike for the summer and may even go with a 26-38-48 crankset before I go on a loaded tour this fall. Since this cog was clearly designed more for MTB gearing, I’m guessing it will work even better with this set-up. This would give me a gear range of 15.8” to 99.5”. If I went really crazy and went with a 22-32-44 I could get down to 13.3”-91.2” on a 26” rear wheel trike with no use of hub gears or mid-drives. That’s pretty impressive. And (providing you don’t need a new cassette or chain) all for the cost of about $50 and a couple hours of tinkering. And maybe a bit of swearing until you get it dialed in…

Unfortunately, MTB Tools only operates on eBay right now. You can find the cog on their store here.