A fourth chainring for touring
 

Has anyone installed these products? It's used to convert a triple chainring set-up to either an ultra-low triple or a four chainring set-up.

Mountain Tamer Triple or Quad

Apparently, to be compatible with a fourth chainring, you need a crank with 74 mm BCD. If you have a 22T chainring, it won't work. I think the minimum might be 26T. But if this system works, you get an ultra-low 16T, 17T, 18T, or 20T chainring.

I am not handy when it comes to bicycle mechanics, so maybe I don't know what to look for. But when I study the bottom bracket and three chainrings on my touring bike, I can't imagine a way to squeeze in a fourth chainring. But it would be fantastic to have super low gears for really nasty hills. With my current setup, I can get up most slopes, but have walked up a few extremely steep ones. I would rather spin fast and travel forward at 2 mph than push my bike.

Is there a point a gear becomes so low that it's hard to stay upright? I am not close to that with my current setup, with a lowest gear of 22-34T.

I always wondered if someone had made a quad. Now I know. I suppose that you could get such a low gear that you couldn't maintain enough speed to stay upright. Seems like in those instances if the hill was really that steep it might be safer to push rather than risk a fall.

This thread takes me back to 1986 when I installed a Mountain Tamer Quad on my Fat Chance MTB that I used for touring back then. The installation was very difficult then. After obtaining the longer bottom bracket spindle it then involved bending the front derailleur cage in several different directions in order to get the chain to drop into the 4th chainring. Upshifting was also a problem at times.
The practical result of all of this effort was to have very low gear inches that involved more spinning and balancing in place than moving forward far too often. The uncertainty of whether the shift would happen made for some exciting moments on steep uphills in loose conditions.

The theory was great but field use was too uncertain and I quickly returned to a triple chainring with a 20 tooth low and a 34 rear cog low to gain useable low gears without the uncertainty during shifting.

I hope that the product has been updated and improved to eliminate my historical problems with the Mountain Tamer Quad. I have had no experience with it since the mid 1980's.

Yeah, doesn't seem worth it to me. Few if any front derailleur cages will cover more than what you can get with a triple. Plus it seems like you'd have lots of issues with cross-chaining / indirect chain lines.

I also don't see much of a point in gears that are insanely low. If you're pedaling at 3 - 4 mph, you might as well get off the bike and walk.

This is overkill for any touring bike. You will never need lower than a 22-34. This could be awesome for a cargo or touring tricycle, as a lightweight and inexpensive alternative to a schlumpf mountain drive or dual cassette setup that some trikes run. a 16-30-42-52 quad on a 20" trike wheel gives a 9-90" gear range. Not too bad.

I really don't see myself wanting lower than 24/32. Just maybe if I toured somewhere with worse hills than I have seen so far, or as I get older, I could see going to a 22/34. Below that I'll just get off and push.

For people who travel with really heavy loads it might make more sense, but I have no desire to carry more than I currently do. If anything I'd like to cut the load a bit.

Neat, though.

To me the point would not be how low can you go, but to tighten up the gear spacing on the rear cassette. My current rear cassette is 12-34 tooth, that means pretty big spaces between each gear. If I could install a 17 tooth fourth chainring, I could go to a much tighter rear cluster and still maintain my lowest gear.

Closer spacing would be nice, but I have my doubt that it would outweigh the disadvantages of a quad for me. A really wide spaced triple with a closer spaced cluster would be interesting if it could be made to shift well. As it is the gaps aren't that bad even with a 11,12,14,16,18,21,24,28,32, so something pretty conventional like a 46/34/24 with an 11-32 really works pretty well.

Agreed, I was just trying to look at it from another point of view.

No, not for everybody, but the idea intrigues me even though I really have no use for one. It`s worth noting that besides going to a four ring set up, the Mountain Tamer also allows a supermini ring (down to 18t, I think) on a triple crank. Michel Gagnon (what happened to him?) has a personal page devoted to mountain tamer on a tandem and gives his set up experience- didn`t sound too dificult. And yes, I think the guy who builds them only does them for 74 BCD.
http://mgagnon.net/velo/pedalier4.en.shtml

If you want closer spacing just lower your top gear. I can't believe the amount of people who think a touring bike need 110 inch gear inch high or more. Pedaling downhill at high speed just does not make sense to me.

Definitely an option, but... I use my top gear a lot (112 gear inches). It would be a rare day that I didn't use my high gear.

The majority of the time I like to spin 80-100 rpm, but sometimes not. Sometimes it feels good to be turning 50-60 rpms for a change of pace. Also on downhills sometimes I like to pedal and go real fast, others I like to be able to keep the legs warmed up by pedaling lightly at a slowish cadence against minimal resistance. Both require a pretty high gear.

I can see your point and your uses for that high a gear. Like anything it's a trade-off. If you choose to have a very low and very high gear it's going to mean bigger jumps, although the younger set is a bit spoiled. On my 1st long tour in 76 I had a double chainwheel and 5 speed cog (remember 10 speeds?). As triples were very hard to find and an extremely expensive conversion I had to get tighter gears by severely cutting my top gear. I ran a 48/38 and 16/28- that's an 81 gear inch high gear and 36 inch low! (Obviously I was in great shape to do that with 35lbs of gear. Back then a typical touring freewheel was 14-17-22-28-32!

Yep I am plenty old enough to remember 10 speeds.

What ever you do it is a trade off and I can see where someone would go to a much lower high gear to get smaller gaps. I personally would really miss it if I didn't have a gear of at least 100 inches or so.

I would like an 11-speed cluster on the crankset and an 11-speed cluster on the back, driving a 14-speed Rohloff hub. I can't do the math in my head but that would be enough, for now.

Meanwhile, Kent Peterson wrote a rant about gearing on his blog this week, which I think is relevant:

http://kentsbike.blogspot.com/2009/0...ring-rant.html

Never? As people age, their muscles don't deliver the same power over time as they did when they were younger. I don't think it's only a matter of conditioning. I'm in reasonably good shape, but I have noticed a difference, since my late-40s, in my ability to climb long, steep hills. It's tougher now. But easier to cope having switched from 24-34T.

22-34T is my lowest gear right now, and it's adequate for most hills; but not nearly low enough for the very long 18% or 20% slope I attempted a couple of years ago. I would like to try a 20-tooth granny, or even a 17 or 18.

According to Michel Gagnon's web site, the quad isn't compatible with STI shifters... and if that's true, there is no quad in my future! I am hoping to be able to swap the 22T for something smaller.

I agree, never say never, as they say. There were some hills in the Ozarks that I could have used a lower gear or two. I have also always believed that it it more effective to ride up a hill than walk, and safer too.

You may not need anything lower than a 22-34 but don't decide for the rest of us. A 104/64 mm BCD crankset can easily handle an 18 tooth inner ring...if someone made one:rolleyes: However somewhere along the line someone decided that those would be silly and limited our choices. Why? Because nobody (read: no one in our racing teams) needs anything lower. If they needed anything lower they could just walk, right?

I've mounted a quad on a mountain bike and it did work. Set up was a bit difficult because of the need for further inward swing on the derailer and the shifter can't be indexed. While you won't use it everyday, there are times when it could come in handy. Climbing out of Clarkston, WA comes to mind as well as Iceberg Pass on Trail Ridge Road.

As for falling over because it's too slow, most people can learn to trackstand. That's zero momentum while still balancing on the bike. 2 to 3 mph forward momentum is more than enough to keep the bike upright. Even at that speed, riding a bike is far more efficient than walking. And pedaling a heavy bike is certainly easier than pushing the bike up the hill by walking.

Fair enough. But I thought 22t was the smallest you could run on a 64, and 20t the smallest for a 58.

They's a gunna start making 11 or 12 by 36 cassettes soon for 1x9 mountain bike and CX market, so one will soon be able to run one of those to get a lower gear. Shimano's gunna offer them in Deore and XT level.

I still wouldn't run four rings on a touring bike. I figure when I'm tired enough to need it, balancing at that slow speed would be tough and I'd rather work out different muscles, even if it does take more total energy. But I am kicking around this design for a luxuriantly hoboesque touring tricycle, and a quad ring would be purrrfect for that.

Dude needs to update his design though. Suntour freewheel cogs--what the hell are those? He's all sold out of the 16 and 17s, so you can't even get the lowest gears theoretically possible anymore. We need a version now that takes hyperglide cogs. And could someone please explain to me how a mere circlip and wavy washer is adeqate to hold the ring on?

We used them back in 1990-91 when we toured the Indian subcontinent and they did work quite well. I ended up hitting a rock and bending mine, rendering it useless, but John used his quite a bit. You do go very, very slowly, but he could balance OK with it.

I don´t know the technical side of putting them on - a friend of John´s was the guy who desinged them so they worked together to get them on the bikes and I had nothing to do with it.

Boone rings makes - or made - a 20 tooth ring for 64mm inner. I have 20 tooth for 58mm and have had as low as 18 in the past. Avid even made an adapter for a while that would allow your to change a 110/74 to a 20 tooth inner ring. I think I even have one on an old crank around here.

I'll agree on the Quadtamer, however. It's the same product I used 15 years ago and finding the cogs for it might be difficult. However, I doubt that he sells many of them a year.

Modern 36t cassettes on the way? Cool- hope they make a version for 7 and 8 speed. And if they really have to, I suppose they could always knock those silly 11 and 12 tooth sprockets off the outside to make room- not like anybody needs those anyway. Hell, if you`re shooting along at 30+ MPH, you might as well drive.