There's a few companies making 40t and 42t replacement cogs for 10 speed cassettes. Here's one of them: OneUp Components US - 40/42T Sprocket + 16T

This is a much better option than putting a 20t or lower chain ring on, as the smaller rings up front increase chain tension, while larger ones in the rear give the same benefit of lower gear inches, but without the increased chain tension. Larger rear cogs do, however, put more stress on the cassette body and hub, so you'll definitely want a nice beefy rear hub, but a beefy rear hub is easier to manage than constantly snapping chains with a 17t chain ring.

I'm confused. No one is talking about a 17 tooth chainring. Do you mean a 17 inch gear, perhaps? Either way, I have never snapped a chain of any kind and I ride gears that are lower than 17" all the time in high torque situation (steep off road riding in rocky terrain). I also ride 20 tooth inner rings and haven't had any problem with them. I haven't had any troubles with a freehub breaking either although, given the choice, I'd rather break a chain than a hub. A chain I can fix on the side of the road but a hub is a whole different animal.

One of the earlier comments by 'Tourist in MSN' linked to a thing called "Mountain Tamer Triple adapter - LOWER GEARS for bikes of all kinds", which when you follow that link, it's a device to allow as small as a 17t chain ring to be installed. This device also allows 18, 19, 20, and higher, but it seems silly to buy such an adaptor when cranks with 20 and 22t are already available. If someone were to put this thing on, I'd guess the whole point would be to go from a 20 or 22t ring to a 17t. This would increase chain tension quite a bit, and while repairing a chain is much easier than repairing a hub, buying a decent hub means such a repair is probably never needed.

It's not possible to buy stronger 10 speed chain, while putting a bit of money into a good hub with steel parts instead of alloy, and a reliable pawl mechanism can pretty much reduce the chances of hub failure down to a level not worth worrying about. I'd rather break a chain than a hub too, but I'd rather break neither more. A decent steel (at least steel cassette body and innards) and a 20t ring up front with a 40t in back will give as low of inches as can be really used (~13") without putting more stress on either the chain or the hub than can be reliably tolerated.

A mountain bike triple mated to the cassette or freewheel of choice should give you all the gear range you would ever want or need on a touring bike.

With a modern 11-34 cassette and a 22/32/42 the gear range is 17 to 104 gear inches on a 622:38 wheel and is 17 to 98 on a 26 by 1.9... the low gear does not change as much when you change wheel sizes and anything over 100 gear inches on a touring bike is going to be pretty much useless unless you like descending at 80kmh.

With the mtb triple, changing the 42 to a 44 on the 26 inch wheel matches the top gear you would get on a road wheel.

The compact triple I have on my Cascade can run a 20 tooth granny so I mated that with a 12-32 7 speed which gives me 16 gear inches, the 44:12 gives me 95 gear inches up top and if I spin that out I'll be doing 55-60 kmh and did hit 50kmh on the flats this past weekend.

Most of us have been discussing bolt-on 20 tooth inner rings rather then the Mountain Tamer. I've used the Mountain Tamer Quad (2 chainrings) in the past and never had a problem with breaking chains nor hubs. But the Mountain Tamer requires a 5 arm crank without forged standoffs for the inner ring. That configuration is rather rare and, if CrazyLemurBoy is looking at getting a 20 tooth inner, I'm assuming that he is using a 4 bolt mountain bike crank with 104/64 BCD which is the only widely available crankset taking that small a inner ring.

The problem lies in defining a "good hub". With the exception of a few high end or boutique hubs, the vast majority of freehub bodies are already steel. Even then, the quality of the freehub doesn't vary from hub to hub all that much. They are all very good.

On the other hand, there is no such thing as a "decent" or even fair all steel hub on the market. All steel hubs are found in department store bikes and are all very bad.

Hi everyone,

Thank you all for the thoughtful responses. I am quite adept at slow speed riding.I come from an mtb background which provided awareness of slow speed rock crawling up steep grades offroad So no worries going at speeds my cycle computer cannot pickup. One thing I need to consider is my handlebar setup. I notice my road drops are much harder to handle at slow speeds than my riser MTB bars due to the width. Anyone touring on these newer alt bars and like the improved uphill handling? How about downhill? I usually climb in the hoods and descend in the drops.

More details about my setup: I'm using an Shimano FC-M430, 175 mm crank arms, with 48/36/22 chainrings. My rear cassette is a 13-34 8 speed job I constructed from a 13t lockring, 11-30 SRAM 8 speed cassette, and a 34t shimano megarange cog I stole from another cassette. 13-15-17-20-23-26-30-34. The jump from 26 to 30 is not that great, and from 30 to 34 it honestly feels very small when I want that extra oomph for getting up hill.

I have seen these 40 and 42T from One-Up and other manufacturers, but they are all specify 10 speed usage only. I know the cogs are slimmer on a 10 speed Shimano unit from 8/9.
The noted fleabay manufacturer 'mtbtools' has some larger cog as well which are built for 8/9 speed, but I am highly skeptical. I hear many reports of those rings bending under load, and I have plenty of that. Nor I am keen on the concept of it throwing a chain into my pricey rear wheel. I also hear that the manufacturer doesn't stand by the product at all. Disappointing.
I looked at the 39t from ActionTec but boy is pricey and knowing I could get 3 more teeth... leaves me wanting more. Interestingly the 20t chainring seems to be priced about the same (heat treated titanium version).

Fietsbob, I am interested in that Mtn tamer quad. I assume this is the older model no longer sold with the longer spline that can accommodate 2 cogs? Or am I mistaken.

Sounds like I need to talk with my therapist about the potential benefit of shorter crank arms. I was actually looking at getting 180 or 185 mm cranks in the hopes that would help.

All in all, great discussion everyone. Thank you for sharing your experiences in this area.

older yet, the 16t threads on.. you unscrew it with a chainwhip ,but it's small enough to unscrew the bolts between the cog teeth .

pm & we can talk off list .