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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?

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    Not an answer because I’m not sure it works, but: Couldn’t you change the chainrings? The 30 teeth chainring has a 74mm bolt circle diameter for which the smallest chainring would be 24 teeth. You’d have to change the largest chainring as well to be within rear derailleur capacity. If you are okay with e.g. an 48 teeth large chainring it could work just fine. – Michael May 11 at 5:27
  • A gearing that goes below 1:1 (30ring and 30cog) will make restarting uphill rather wobbly because of the high cadence needed to attain enough speed for stability. – Carel May 11 at 8:12
  • You need to clarify the question for a precise answer. You say it has a 9 speed cassette but your link to the spec indicates 10 speed 5700, while 2015 bikes could have 11 speed, since this came out in 2014. However I don't think 5800 series come with triple front gearing. Hence the conflicting answers already written, under different assumptions. And the right answer depends on how many cogs on cassette, so you will have to edit a clarification and add photos of the actual bike – Swifty May 11 at 8:29
  • @Swifty you're right, I had a mistake in my post: my cassette has 10 cogs, not 9. What specific bike parts would you like to see the pictures of? – Macondo2Seattle May 12 at 3:22
  • @Carel: Lots of MTBs have gearing ratios far below 1:1. 32 teeth cassette and 24 teeth chainring is quite common. Or even 36 teeth cassette and 22 teeth chainring. At 60rpm the later would give you ~5km/h (or ~8km/h at 100rpm). – Michael May 12 at 8:33
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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.

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  • What about an MTB rear derailleur? Or a smaller large chainring? Though it doesn’t change the fact that a 9 speed 11–34 cassette would have very large gear steps. – Michael May 11 at 5:03
  • An MTB rear derailleur won't work out of the box due to differences in cable-pull ratios, although there are adapters that can translate. A smaller big ring isn't a bad idea, but doesn't solve the problem of this derailleurs max sprocket size. – Adam Rice May 11 at 13:15
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    A 9 speed MTB derailluer will work just fine with 9 speed 105 shifters. – Fred the Magic Wonder Dog May 11 at 13:43
  • I stand corrected! – Adam Rice May 11 at 16:00
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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.

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    It took me a surprisingly long time to realise that pedalling uphill at 65rpm is actually a viable option. I love to spin at 95rpm and it takes a conscious effort to take it slow and easy when I run out of gears. – Michael May 11 at 7:01
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    For touring MTB-style clipless pedals and shoes are the best option anyway because they allow walking on otherwise unrideable sections. – Carel May 11 at 8:16
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    @Criggie Thanks for the answer! This is solid advice. – Macondo2Seattle May 12 at 3:32
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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.)

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  • Thanks for the answer. I realized there was a mistake in my post: the cassette has 10 cogs, not 9. So If I go down the route of replacing the crankset with a 24/36/48 triple, can I keep the front derailleur? Sounds like it'd also require shortening the chain, is that right? – Macondo2Seattle May 12 at 3:30
  • Yes, the front derailluer only cares about double or triple. If you went really small with an MTB triple you might have problems, but 52 down to 48 should be fine.Unfortunately, 10 speed is where everything gets complicated between mtb and road. – Fred the Magic Wonder Dog May 13 at 0:28
  • @FredtheMagicWonderDog 10 speed is where everything gets complicated between mtb and road Not for 105. 5700 was the last 10-speed 105, and it's the "old" 10-speed that works with 9-speed MTB derailleurs. 5800 is 11-speed with the "new" pull ratios. – Andrew Henle Jul 1 at 9:37
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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.

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    Would the Alfine still be in the allowed torque range? I recall that the spec was quite picky about the gear ratio. – Michael May 11 at 5:00
  • @Michael good point - Shimano's suggestion is "not to exceed a ratio of 1.9:1" between chainring and cog. So that would be a max 38 tooth chainring on a 20 tooth cog, or ~35 on an 18. Personally I have 26/38/52 chainrings with an 18 tooth cog, and that's 2.88:1 which is much higher than specced. I ride the big ring 99% of the time, and only get to the middle ring when on a steep climb. I've done a 13% 4km grade in the middle ring (okay it was only 4.5 km/h !) – Criggie May 11 at 5:38
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    Wouldn't that be the other way round? A smaller gear ratio should put a higher torque onto the drivetrain. It's like using a longer lever: Your crank arm travels more, while the rear sprocket moves less. – NoirDesir May 12 at 17:40
  • @NoirDesir the shimano limit is about high gears, so a big chainring and a smaller rear cog. The chainring should be no more than 1.9x the tooth count of the cog, so my 18 tooth should be no more than 35 teeth, but I have a 52, technically out of spec. Works fine for me, for over 10,000 km. – Criggie May 12 at 21:45

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