What is the simplest way to lower the gearing on my touring bike?

Question

I have a 2004 Jamis Aurora with a 52/42/30 triple and an 11-32 cassette in the back. 30x32 (25.3 gear inches) being the lowest gear is frustrating for the hilly terrain where I live (e.g., 7% grade average over several miles, with higher local steepness), and so I'd like to lower my gearing.

I'd like advice on how to most simply do this. The basic problem is that replacing any given part appears to have cascading compatibility issues which may or may not be solvable, and I'm becoming confused.

I do use the full range up to 52x11 (127.6 gear inches), but only on descents that are fast anyway, so I am happy to lose the higher gears and coast instead. There is essentially no level terrain where I live.

Relevant specs (all parts stock in 2004):

• 9 speed
• Crankset: Truvativ Touro 52/42/30, 130/74mm BCD
• Front derailleur: Sora 28.6mm, clamped
• Cassette: SRAM 11-32
• Rear derailleur: Deore SGS
• Shifters: Tiagra
• Bottom bracket: TruVativ sealed cartridge, 68 x 113mm

Options that I've found so far:

1. Add a larger cog in back, such as the new Shimano 12-36 cassette. As far as I can tell, this will require a new rear derailleur and a new chain, but that's it. This makes the lowest gear 30x36 (22.5 gear inches), 12.5% lower, and the highest 52x12 (117 gear inches). A downside is the excessive size of the rear cassette.

2. Replace the crankset, for example with a 48-36-24. This makes the lowest gear 24x32 (20.3 gear inches), 25% lower, and the highest 48x11 (118 gear inches). At first glance, this one is the most appealing, but it seems to also raise the thorniest compatibility questions; the ones I'm aware of so far are (a) finding a front derailleur which is compatible with both my road shifters and the smaller large chainring (one possibility), and (b) differing chainline offsets of road and MTB cranksets.

3. Swap in a lower granny chainring, say 24 teeth, resulting in a 52/42/24 crankset. My concerns here are (a) whether my derailleur can handle the 18-tooth jump between low and middle and/or the lowness of the granny gear, (b) the awkwardly wide jump between low and middle (75%, or about 5 sprockets), and (c) retaining very high gears that are feasible only for making a fast descent faster.

4. Swap in 3 new chainrings. This seems to raise similar concerns to item 2.

Answer 1

I think everyone has provided some pretty sound advice, especially Daniel Hicks and his recommendation to go with the quickest and cost effective option by replacing your chainrings! With a 130/74 BCD, an ideal setup would be to swap in a 24/36/48 which would give you a great range at a cheap price.

The front derailleur is probably the least necessary component on your bike and, while shifting compatibility is a concern, I would recommend swapping in your new chainrings and setting everything up to test for compatibility before spending more money on a new derailleur. I have used mountain FDs on road triples and road FDs on mountain triples with a variety of indexed and non-indexed shifters and have had very little trouble over the years. Really, the only requirement is ensuring that the front derailleur is a triple and has the correct seat tube diameter/pull direction. (Your cascade of compatibility issues is something I've dealt with, but don't worry! There are lots of manufacturers who design compatibility issues into their gear, but they generally don't cater to the average touring enthusiast.)

Since you have an SGS derailleur (long-cage) you shouldn't have any issue with chain slack. For touring, the Deore SGS set up with an 11-32 is a great choice. At most, you may prefer to remove 1 or 2 links just to clean everything up. (I ride in New England on 24/38/48 x 13-32 and even with a full load I maybe walk it once a year).

When you start changing components such as your crankset you have to deal with special tools, frame clearance issues, bottom bracket fit, and Q-factor (the horizontal distance between your pedals). Mountain cranks have smaller BCDs but have much wider Q-factors which, for some people, can cause knee and hip irritation (which is exacerbated by long rides and clipless pedals). Long story short, if you are comfortable with your bikes ergonomics on long rides, leave it (or give yourself enough time to work out the bugs before attempting a 2k fully loaded).

Otherwise, take things one step at a time. If smaller chainrings don't give you enough oomph, throw on a new cassette which is quick and has few compatibility issues (12-36 is a common low touring range). More compact road cranks have a 110/74 BCD which won't help you on the low end (though, if your leg length permits a longer crank arm it might provide a very small advantage). Some mountain cranks have BCDs as low as 58mm x 20t, but I suspect that this option may be more trouble than it is worth. Some handy online gear resources include: rivbike.com, velo-orange.com, universalcycles.com, and sheldonbrown.com.

A cheaper way to ease the inherent suffering of long, steep climbs would be to trim some bike fat and touring load (a good technical and philosophical resource might be The Ultralight Backpacker by Ryel Kestenbaum or Just Ride by Grant Petersen). Some people might recommend trimming some actual fat, but we live in a world where everyone gets to ride a bike, not just 130 pound-25-year-olds. (No offense to the 25-year-old cyclists out there!)

Answer 2

The simple answer is that there is no simple answer. You have a triple, and a decent gear range on the cassette, so there is no obvious direction to go which you can use to say, "This is the right way. Do this."

Any of the options you show should work. If it were me, I'd do the first one:

Add a larger cog in back, such as the new Shimano 12-36 cassette. As far as I can tell, this will require a new rear derailleur and a new chain, but that's it. This makes the lowest gear 30x36 (22.5 gear inches), 12.5% lower, and the highest 52x12 (117 gear inches). A downside is the excessive size of the rear cassette

Size of the cassette is not much of a downside, and anything else on your list is likely to cause you headaches. The issues can be worked out, but not without a lot more detailed information about what components you have.

Of course, if it were me, I'd not feel a need for an easier gear than 25 inches per revolution, but that's a personal thing.

Answer 3

If you tour with a load, I suggest at least putting in a 22T ring up front. On loaded tour going up hill, in the rain, you have the greatest range of low gears. If present cost is a factor, this also reduces your chances of having to replace the chain.

If cost is not a problem, and you love to tour hilly country and you pack gear, the cost of a new chain, new cassette, and whatever it takes to get a 22T in front, IMO, is still pretty affordable. If your LBS has outrageous rates, they'll charge you more for labor than the approx $80USD in parts this new drivetrain will cost you.

On my Xtracycle, I run a 42-32-22/34-11 and I am frequently in 22/34 when I'm loaded up or on a hill. I might be hauling 60 extra pounds, but that 22 in front keeps me from killing myself and I rarely have to stand on my pedals.

I'm investing in a newer cargo bike, and I'm requesting it have a 9sp 42-32-22/36-11 setup. This is not a light bike, but I know I'll load it up. I could go lower if I wanted 10sp and get a 22/38T combo.

Answer 4

For touring in the high mountains I use Tiagra STIs, a Tiagra 4503 front derailleur, a Deore M530 chainset set up with 48/32/22, an XT M761 rear derailleur and an XT 11-34 cassette.

Having the FD high enough for the 48T ring means that it won't shift into the granny from the middle when in sprockets 6-9 on the rear, but otherwise this combination works fine.

I haven't found this to be a problematic restriction since if I need the granny I am probably in the lower range of the cassette already, so on a long tour I might accidently leave it in too high a sprocket say 2-3 times. Note that with a 44T ring the derailleur works fine.

So my advice would be to get an MTB chainset and BB, and move the FD down and it should work fine. Depending on the chainline of the chainset (usually 50mm for MTB versus 43-45mm for a road triple), you might need to shim out the FD on the drive side of the seat tube so that the reach is correct for the chainset.

PS: I use the 48T when trying to set my personal speed records down steep mountains, and this is just too much fun to sacrifice (currently 54.2 mph). For normal flat cruising with my preferred cadence however, the 32T middle puts the chain right in the middle of the cassette.

Answer 5

Mountain derailleurs (which fit mountain gearing) are readily available. However, mountain and road derailleurs use different indexing, so you need a shifting adapter. John Allen, the person to whom Sheldon Brown passed the torch, so to speak, states on http://www.sheldonbrown.com/drivetrain-mixing.shtml#adapters about using a JTek Shiftmate pulley for correcting cable pull.

On JTek's site, they have two varieties of Shiftmate: the standard (for mixing SRAM, Shimano, and Campagnolo RD's and shifters), and the straight one (for mixing Campangolo, SRAM road, SRAM non-road, Shimano road, and Shimano mountain).

As your shifter is Tiagra and you're correcting the front shifting, you're going to want the Shiftmate Straight #7S in order to use a mountain FD.

Bike shops and distributors stocking JTek products can be found on http://jtekengineering.com/dealers.htm.

Answer 6

I have a touring bike with a 48-34-24 chain ring combination and a older Ultegra front derailleur and it shifts quite well. If you are concerned about the front derailleur, IRD makes a front derailleur called the Alpina-D that is optimized for a 48-36-24 and works with standard Shimano shifters. (I've not used it but I've looked at it.)

Follow-up: I recently rebuilt my bike and installed and IRD Alpina-D front derailleur. The front shifting did improve. The different profile of the cage made shifting and adjustment easier.

Answer 7

The quickest and cheapest (in the $20-$30 range) way to get lower gears would be to get a 9-speed cassette with bigger sprockets. The 12-36T (Shimano HG400) gives you a 12.5% lower lowest gear and will work without any other changes. Sunrace makes a 11-40 9-speed cassette (CSM980) that should/could be compatible with your existing derailleur. That would give you a 25% lower lowest gear.

Answer 8

I'm looking at this problem myself. The 11-40 cassette is a good option, but I think you'd have trouble running it with a triple up front. 20t difference on the front with 29 on the back exceeds the capacity of most (if not all) rear derailleurs. If you stick to only two front cogs you'd be ok though. I've heard of others using the Shimano cx front derailleur for this application with 36/46 gears. Personally I'm going to try the 12-36 cassette and a smaller inner ring next, this may involve needing a rear derailleur with more capacity though. If this doesn't work I'm going to raid the mtb parts collection and go with a shiftmate. Btw, in the past I've converted an old LX front derailleur to road cable pull ratio by simply moving the cable to the other side of the clamp bolt, it worked very well but my FD only went to 42 tooth big chainring which was too low for me.