Compact (50/34) with 11-34

Hi,
I have a canyon grail and I would like to swap the current Shimano 11-32 cassette for the newer Shimano 11-34. For a 1-1 ratio in the small ring. As far as I know, the only potential issue is the bigger jump in gears.

I live in a hilly area, mostly doing climbs in road and gravel. But also enjoy the big ring in the flats or going down. Would preferably change just the cassette and not the drivetrain. The additional 34 would help me in some challenging gravel climbs.

3 questions:

  • Is this issue of bigger jump in gears just a personal “feeling” preference?..Or it has real practical implications?. How would I know if I is an issue for me before trying?

  • Would I be able to keep the 11-32 cassette in my trainer?

  • I wonder if ppl in this forum have experience with this specific change and if there’re any other particular issues I should be aware of.

Thanks!

I run this set up and love this combo on my aspero.

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My road bike came with Ultegra 6800 11-32 and I swap over to an 11-34 when I travel to CO. I need the 34 on the long steep climbs. I have an 11-28 on my trainer. No issue at all - derailleur and chain work with all just fine.

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I just changed to the 11-34 as well for the steep punchy climbs I ride nearly every day, I want to be able to spin a higher cadence at 8-10% climbs

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I switched from 11-28 to 11-32 in early 2016, and then a year+ ago switched to 11-34. Been running 11-34 since then. The original 11-28 is on my Kickr 2017. No issues with the original Ultegra 6800 derailleurs, or with the 8000 series derailleurs now on my bike.

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Yep I have that combo and works great. I have a few 10-20% climbs on my commute to work and every gear helps

Also I have a 32 on the trainer with no issues

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Good to know on the trainer!

I went the opposite direction by accident when my local shop replaced my 11-34 with an 11-32 and I didn’t realize it until I got home. I didn’t change the cassette on my trainer, and I don’t notice the smaller jumps between gears at all.

I also live in a hilly area and I miss my 34.

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I’d be really surprised if you could feel a difference in the larger jumps. There are only 2 shifts along the cassette that will be any different anyway; all others will retain the exact same gap.

In general, I don’t always understand the desire to retain such small gear jumps at the expense of losing total gear range. Outside of flat time trials, I’ve never wanted it. In fact, in crits and some XC courses, I often find myself preferring bigger jumps. These are basically a bunch of corners and reaccelerations. When I have a tighter spaced cassette block, I find myself spinning up the gear, then grabbing two shifts before hitting it again. I prefer a 32t cassette for crits because sometimes this leads to a bigger jump and I only need to upshift one gear.

Sorry for the rant - just speaking out against a common ‘complaint.’

In related news - if your bike currently has a GRX or Ultegra RX cassette, you can actually fit a 40t cassette, even though Shimano claims only 34t would work. Swapping from the 40t on the wheel over to 32t on the trainer shouldn’t be a big deal. In theory, the b screw adjustment would be too tight on the 32t (assuming it was set properly for the 40t), but I doubt you’d notice any issue with indoor riding.

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I live where it’s flat so no need to tolerate the jumps everyday but I swap to 11/34 if going to the mountains, the jumps don’t bother me near as much as grinding too big a gear uphill would.

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I think you should also consider SRAM’s 11-36 cassette. Not only does it have more range, but unlike the Shimano cassette the first three gears are spaced 1 cog apart, which makes a difference. On my mountain bike the only time I can negatively feel a large jump is when I shift from 13-tooth cog to my 11-tooth cog (the 2nd smallest to the smallest). Shimano’s 11-34 cassette has the same large jumps, and I don’t think this seems like a pleasant cassette to use on a road bike.

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In terms of gear ratio, a 1-tooth step in the 11-13T range is roughly equivalent to a 3-4T step in the 34T range.

Close gearing is much more important on flat routes than in hilly, up-and-down ones where large changes in slope, speed and cadence are the norm. The best solution to handle both is to have two cassettes, and an RD (and chain length) than can handle either.

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As percentages, yes, but that is forgetting about the different roles inertia and body position play: when you are riding fast, you are either on the flats or going downhill. So your range of preferred cadence moves up and the range of acceptable cadence narrows. Conversely, when you climb, your preferred cadence slows and more importantly, the range of acceptable cadences broadens (compared to your top gears).

That’s why a 17 % jump at the top-end of the cassette feels very different from a 17 % jump at the climby end of things. This is why IMHO Shimano’s 11-34 cassette has not-so-great ratios for a road bike. In fact, I really don’t get who this is good for: for roadies the lack of 1-tooth jumps is an issue, so IMHO SRAM’s 11-36 is IMHO better. And if you are ok with 2-tooth jumps at the top end, I’d want to have more range, e. g. Shimano’s 11-40 cassette. I see a lot of people who need way easier climbing gears, and I don‘t see a reason why they shouldn‘t try a 11-40 cassette.

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I can see your argument for XC racing, and crits (and actually agree with it for CX racing), but for long rolling or windy road or gravel rides, particularly solo or in a small group, I’ll take the small jumps in the rear to maintain comfy cadence ranges for longer periods of the time.

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I’m thinking this 11-34 could be good for me. The current 11-32 works 98% of the time. But in steep ( > 15% ) gravel climbs I need another gear. Specifically, there’s this gravel climb where it’s all good 5-10% the first 80% and then the last mile or so is brutal 15%-25% of gravel, where you are also dealing with the adherence of the surface. Most people do it on Mountain Bike or they have Gravel Specific Gear…I want to keep my compact and try the smallest change that could help me in these particular climbs.

IMHO SRAM‘s 11-36 cassette has better gearing, though, even if you could make do with a 34-tooth cog. Have a look at the gear jumps of the two cassettes. The 11-36 still behaves like a road cassette with 1-cog jumps at the top and identical gears compared to other SRAM cassettes. Shimano‘s 11-34 cassette has its tightest gearing in the soft climbing range, so it will feel very different from an 11-32 cassette.

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But, is this even an option for me?..namely, can I use this cassette in conjunction with all the rest of Shimano components?. H

Yes, 11-speed components from SRAM are fully compatible with Shimano.

I run a SRAM 11-32 cassette on rear wheel even though my bike that is equipped with a mix of Ultegra and 105. I prefer SRAM‘s gearing. This works perfectly. I use my old Shimano cassette on my trainer.

Officially, Shimano supports only 34 teeth with their rear derailleurs, but AFAIK will accept the 11-36 cassette just fine. Should you need more than 36 teeth, then you need to get a Wolftooth extender. Then you can fit e. g. a Shimano 11-40 or 11-42 11-speed mountain bike cassette as well.

SRAM‘s 11-36 cassette has identical gearing to its 11-32 cassette, it just takes out the 14-tooth cog and puts a 36-tooth cog at the end. And likewise, its 11-32 cassette is identical in gearing to its 11-28 cassette, you just trade a 16-tooth cog for a 32-tooth cog.

Thanks @OreoCookie for the link to the gear calculator and the information you shared. The 11/36 sounds appealing as I’m 71 years old and some of the steeper hills here in SW Washinton are getting a little tougher to get up these days especially the 12 to 19
% ones. I’m running 50/34 - 11/32 gearing presently. If I go to SRAM’s 11/36 cassette can anyone tell me or share a link to calculate how many additional links I need to add to my chain? I have a Di2 RD-M8050-GS rear derailleur and my chain has 110 links. And can my GS rear derailleur handle this large casette (36 teeth).

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With a Wolftooth extender for absolutely sure. Without one, according to anecdotal evidence yes, you can.

If you get the very cheap Wolftooth extender, you can also put in even larger cassettes, e. g. an 11-40 or 11-42 cassette. Cycling should be fun, and grinding uphill in a gear that’s way too tall isn’t fun.

I’d probably get a new chain just to be on the safe side. I reckon you could get by with your old chain, but I don’t see a reason to skimp on that. Park Tool has a great video that explains how to size chains.

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