Tree-climbing gear for my gravel bike?

[BumbleBeeDave]

On my Lynskey Pro GR I’m currently running a Shimano GRX 31-48 crank on the front with the rest of the group eight-year old Ultegra 6800 11-speed with 11-36 on the back. I’m a spinner, and this 31-36 combo is just not low enough for me.

The Ultegra needs to be replaced anyway, as it's eight years old and has seen a lot of miles, plus my left brake lever (hydraulic) is not working really well any more. I want new stuff.

I’m planning to replace the rest of the Ultegra with mechanical GRX and keep the current crankset, if possible, given that I just bought it a few months ago. But the lowest I can get with the two ring GRX group is that same 31-36 combo.

Is anyone here running a mullet setup with a bigger cog in the back for lower gearing? If so, what parts are you using and how reliably does this setup work? I’d like to run at least a 42 cog in the back and possibly higher.

Also, I know a one ring setup would let me run a 40 front and something ridiculously big in the back for lower gearing. But what are the disadvantages–if any–of only having 11 active gears instead of the 22 with the two-ring setup? Too big a jump between gears? If you ride this setup has that been a problem for you?

Any comments/advice appreciated! I don’t want to get this all bought and built up and find it doesn’t do what I need/want.

BBD

[EB]

As far as I know, the furthest that you can stretch this is with a Wolf Tooth RoadLink, but that won't get you farther than an 11-40 cassette in 11 speed. Lowest ratio with your small ring would be 31/40 = 0.775. This is pretty low!

I've been in your shoes, and I switched to 1x12 systems, which provide access to 10-50, 10-51, and 10-52 cassettes depending on whether you are using GRX or SRAM flavors. This will give you the stump-pulling gear that you're after without sacrificing too much top end and with reasonable ratio gaps. Chainring choice of course terrain and geography-dependent. A 40 tooth chainring on a 10-51 gives you a low gear of 0.78, very similar to the 31/40 possible with a RoadLink on your current setup. Going to a 38T chainring gets you to 0.74, which is lower.

Caveat that I do not ride in big packs anymore, nor do mind the gearing gaps while riding solo - if either of these two things are important to your riding, 1x may or may not be for you. Otherwise, that's my recommended route.

[truth]

Originally Posted by BumbleBeeDave

On my Lynskey Pro GR I’m currently running a Shimano GRX 31-48 crank on the front with the rest of the group eight-year old Ultegra 6800 11-speed with 11-36 on the back. I’m a spinner, and this 31-36 combo is just not low enough for me.

The Ultegra needs to be replaced anyway, as it's eight years old and has seen a lot of miles, plus my left brake lever (hydraulic) is not working really well any more. I want new stuff.

I’m planning to replace the rest of the Ultegra with mechanical GRX and keep the current crankset, if possible, given that I just bought it a few months ago. But the lowest I can get with the two ring GRX group is that same 31-36 combo.

Is anyone here running a mullet setup with a bigger cog in the back for lower gearing? If so, what parts are you using and how reliably does this setup work? I’d like to run at least a 42 cog in the back and possibly higher.

Also, I know a one ring setup would let me run a 40 front and something ridiculously big in the back for lower gearing. But what are the disadvantages–if any–of only having 11 active gears instead of the 22 with the two-ring setup? Too big a jump between gears? If you ride this setup has that been a problem for you?

Any comments/advice appreciated! I don’t want to get this all bought and built up and find it doesn’t do what I need/want.

BBD

I've done 40 and 42 with Ultegra and Ultegra RX RDs. It works, the shifting's not 100% crisp.

What 11 speed 11-36 cassette do you use?

[BumbleBeeDave]

Originally Posted by truth

I've done 40 and 42 with Ultegra and Ultegra RX RDs. It works, the shifting's not 100% crisp.

What 11 speed 11-36 cassette do you use?

Not sure what exact part number.

[cgolvin]

Nothing to offer on the specific components you've got, but on what follows, I do.

Originally Posted by BumbleBeeDave

Also, I know a one ring setup would let me run a 40 front and something ridiculously big in the back for lower gearing. But what are the disadvantages–if any–of only having 11 active gears instead of the 22 with the two-ring setup? Too big a jump between gears? If you ride this setup has that been a problem for you?

I ended up going 1x on my allroad bike, using Ekar, with a 38 chainring and a 9-42 cassette. While not quite as low as your 31-36, it's a plenty low gear for anything I encounter. The tradeoffs are the big (6 tooth) jumps to the final two cogs and the not-quite-big-enough 38-9 big gear while descending. The smaller portion of the cassette has 1 and 2 tooth jumps so it's no problem finding a good cadence on the flats, I just accept that when climbing steeper things I'll make do with a less than perfect cadence, no problem.

And remember that your 2x system doesn't really have 22 unique gears, there's plenty of overlap. I still much prefer 2x for the road but I'm finding this 1x setup works very well for mixed surface (and even for pure pavement).

[fa63]

This is the main problem for me with 1x; the jump between cogs. Some people seem not sensitive to it at all but I guess I am.

You could switch out to a Shimano 46/30 crankset in the front, and also go with a 11/40 cassette in the rear. I don't think the 6800 rear derailleur will work with that cassette without a RoadLink; people report that the newer RX or GRX derailleurs can.

Originally Posted by BumbleBeeDave

Also, I know a one ring setup would let me run a 40 front and something ridiculously big in the back for lower gearing. But what are the disadvantages–if any–of only having 11 active gears instead of the 22 with the two-ring setup? Too big a jump between gears? If you ride this setup has that been a problem for you?

[hokoman]

The white industries cranks have jumps as high as 20 teeth from the small to large. I replaced a 50/34 with a 46/30. I also have a set of cranks that are 44/24 - those are going on a bikepacking bike, so can't comment on the shifting, but can't imagine that WI would sell a terrible shifting crankset.

Something like this might work well...they offer chainrings in 2 teeth increments so you can customize. More expensive up front, but might be a better solution for lower gearing than going bigger cassette jumps.

[SlowPokePete]

Curious if the 30/46 from a FRX610 would fit your crankset....

SPP

[bikinchris]

Scratch all of that. Get a Road Link and put a cassette with a 42 tooth low gear and be done with it.

[RoosterCogset]

Get a motor, maybe it's time?

[weisan]

Originally Posted by EB

As far as I know, the furthest that you can stretch this is with a Wolf Tooth RoadLink, but that won't get you farther than an 11-40 cassette in 11 speed. Lowest ratio with your small ring would be 31/40 = 0.775. This is pretty low!

Originally Posted by truth

I've done 40 and 42 with Ultegra and Ultegra RX RDs. It works, the shifting's not 100% crisp.

Originally Posted by bikinchris

Scratch all of that. Get a Road Link and put a cassette with a 42 tooth low gear and be done with it.

I have the same consideration and was able to accomplish the objective using a roadlink, proper chain length and with a bit of fine-tuning and patience to get the shifting performance to acceptable range.

I have the following in my current lineup of bikes:

Bike #1 that serves dual duty both as gravel and road
GRX Di2 11 speed
2x
front 52/36
rear 11-42

Bike #2 also serves dual duty both as gravel and road
Ultegra Di2 11 speed
2x
front 50/34
rear 11-42

Bike #3 Pure gravel bike with monster tires
GRX Di2 11 speed
1x
front 38
rear 11-50

[Dave]

I also found that a 30/36 wasn't enough and built a 46/30 GRX crank with SRAM AXS 10-44 cassette that will produce 4.3 mph at 80 rpm. It was too low for most of my needs, but the 38 was helpful. All it takes is a wolf tooth road link and sequential mode so you don't accidentally shift to the big/big.

This May I finally wised up and bought a Cervelo Rouvida with a Fazua Ride 60 mid drive. It's 1x with a 46 chain ring and 10-44 cassette. It's got enough power that even the 46/44 low is rarely used. I switched to a 48 chain ring from garbaruk to work better at the 28 mph assist limit. I've been riding 3-4 mph faster on my regular 60 mile rides.

[Ken Robb]

I have never been able to enjoy gearing lower than 1-1. I had a 30 ring and 32 cog but I couldn't spin fast enough in that gear ride fast enough up a steep hill as fast as I could walk the bike up that hill.

I'm curious about chain wear when using a 9 tooth cog because that seems to me to require severe flexing of the chain. I suppose the cog would also wear faster but I think most riders wear out chains much faster than cogs.

[dmitrik4]

My newest garvel bike has 1x12 GRX 820 (40T / 10-51) and I haven’t found a situation it wasn’t geared for. It will climb anything and the 10T cog gives me plenty of road speed. Highly recommend

[Jaybee]

Originally Posted by truth

I've done 40 and 42 with Ultegra and Ultegra RX RDs. It works, the shifting's not 100% crisp.

What 11 speed 11-36 cassette do you use?

Same, but with the GRX RD and no special Wolf Tooth link or anything. I did flip the b-screw around to get more clearance from the 42 cog.

Just buying an 11-40 cassette and keeping your 48-31 crank is the easiest option here