Options for adding lower gearing for bike with Shimano 105 drivetrain

Question

I have a 2015 Salsa Vaya 2 with a Shimano 105 drivetrain. It has a Shimano 105 Triple front derailleur with a 30/42/52t crankset. In the back it has an 11-30T 10-speed cassette (installed for me by the LBS instead of the stock 11-28T one). I was told at the time that I can't get a lower-geared cassette on this bike.

Now I'd like to get into some light touring, and want to lower the gearing for climbing with load. What are my options? I see some 105 cassettes with larger big cogs (e.g. 11-34 11-speed). Can I just drop one in? Do I need a different rear derailleur, a new shifter, or any other parts to ensure things work?

Answer 1

There are a couple of parameters you need to pay attention to:

1. The rear derailleur's wrap capacity (how much chain it can wrap up)
2. The biggest gear the rear derailleur can fit under.

With your current setup, your derailleur needs to wrap 41 teeth of chain. It looks like you've got this derailleur, which can wrap 37 teeth and fit under a 32-tooth gear. So you're already beyond capacity in terms of wrap, but if you don't cross-chain, it's probably not a big deal. You could probably get away with a 34-tooth bottom gear by adjusting the B screw on the derailleur (the one pointing straight back, under the hanger) to push the derailleur down.

The current generation of 105 medium-cage derailleurs is designed to fit under a 34-tooth bottom gear and handle 39 teeth of wrap.

Answer 2

Sounds like you're at the limits of what your bike can go to in terms of low gearing.

Other things to try are more into technique:

• try pacing your climbs better. With a large load you will have a longer time up any given grade, so also develop your endurance to sustain an approximate effort at a lower average output for the duration.
• try lessening the grade by taking uphill corners relatively wide. Avoid the inside of a hairpin bend - some of those can be extreme. Just be aware of other road traffic. If there's no traffic you can also reduce the effective grade by wiggling back and forth across the grade, though this means more turns and can't be safe with traffic.
• lighten your load - look at the heaviest things you're taking and see what you can do to make them lighter. Can you camp under a fly not a full tent? Do you need canned food or can you go with dehydrated? Or can you buy food at the destination? Do you need to carry a cooker?
• go a flatter route with touring, its not about the speed. You don't have to take the fastest direct route. Consider taking a longer route with less elevation change, or takes longer to rise.

The best answer in my opinion, is to simply get out there and ride it. If you end up walking the steepest parts, well its still type2 fun and you'll get up it. Just allow yourself as much daylight as possible. Wear flat shoes, not clipless, or at least take some with you.

Answer 3

There are several options for lower gears. Unless you want to replace most of your drivetrain you should stick with 9 speed components. Your shifters and derailluers will only work with 9 spd.

Something that might not be obvious is that with small gears, small changes make a much bigger difference. The diffence between 24t and 26t in the front is nearly 10%. It's about getting a gear that allows you to go up the climbs w/o going into the red zone.

The first and easiest is to replace the 30t inner ring with a 26t one. I'd also suggest going to 39/50 chainrings. You will need some kind of chain catcher to avoid dropping the chain and upshifting from 26 to the current 42 will not be as smooth as shimano normal. 26/39/50 will be much smoother.

Another crank option in the front is to switch to a 110 BCD triple and the standard 24/36/48 touring setup. Since you've already spend some $$ on upgrading the rear cassette, this would be my recommended solution. I think you'll enjoy the range of gears this gives you much more, this is the crankset that bike should have come with out of the box.

Second is switching to a 12-36 or 11-34 9 speed rear cassette. There are two options to shift this properly.

1. Get a 9 speed MTB long cage rear derailleur, this will work fine with your 9 spd 105 brifters. Shimano still sells 9spd MTB gear as replacement parts.

2. Buy a Wolftooth roadlink, this will allow your current rear mech to shift an 11-34 ( I haven't tried the 12-36 with this combo.)

Answer 4

You have 9 speed shifters, you're constrained to a 9 speed cassette.

Your 30:30 combo is 27.0 gear inches now. a 32 tooth would give you 25.3 gear inches, and a 34 tooth would give 23.8 gear inches.

(High gears are 73.6, 103.1, 127.6 gear inches assuming 11 tooth)

If you want to spend up and fit an internally-geared hub with a tensioner, this will let you use your front mech still.

A Shimano Alfine 11 will give ranges in gear inches from

• 21.3 to 87 on the 30 tooth
• 29.9 to 122 on the 42 tooth
• 37.0 to 151 on the 52 tooth chainring, when using a 20 tooth rear drive cog.

Downside, this is not a cheap solution. Or you could go a Rohloff for even greater costs which would be 11.3 to 60 gear inches on the 30 tooth, through to 19.6 to 103 on the 52 tooth.