rumatt

I ride routes that have a lot of rolling hills with steep climbs - 15-20% grade sections is not uncommon. I found a new route with a steep gravel section that broke my sprit. Muscling up is just not fun with my 50/34 compact crank.

I'm ready for mountain bike gearing ranges. What are my options for low, low gearing that won't totally suck on the road?

If I go Shimano 2x it seems the lowest I can go is 30 front, 34 rear. There's no way to run a larger cassette with Shimano 2x? (likely di2. I'm sick of trimming front derailleurs)

Shimano 1x my option seems to be 11-42. With a small chainring that's super low, but that's a narrow range. This can't be used in 2x right?

Apparently with sram 1x I can do 10-50 with wireless electronic shifting. Not sure if the gaps will drive me crazy. I'm not a cadence nazi, but I have my limits.

Im curious to hear people's experiences. Thanks!

tangerineowl

After a year or so of tweaking a climbing setup I have settled on 40/24 with 12/28. 10sp Sram road/mtb mix.

On the flats I tend to sit around the middle of the cassette which I like. The three most used middle cogs (and higher) have 1-tooth jumps.

Prefer having a cassette with minimal jumps.

One I run out of gears on a steep downhill I just coast.

The times I do a light bikepacking ride, that 28t is just enough for me.

rumatt

Sweet. What 40/24 crank do you have? I hadn't considered going below 46/30.

tangerineowl

Easton EC90SL arms, with Race Face 104/64bcd 2x spider. Chinook rings.

Easton has the same in the cheaper alu EA90 crank. Wanted a narrow q-factor (not mtb).

princo

Although unsupported, some people have successfully managed to run an 11-40 SLX cassette with no modifications with the latest 2x Ultegra R8000 and 105 R7000.
https://www.road.cc/content/feature/2...ike-adventures
You can also see that they installed a 46-30 crankset for a final low gear of 30/40.

rumatt

Interesting!

So basically a 1x road crank + a 2x spider designed for mountain biking.

Do you know what kind of chain line that creates? Did you use the boost or normal spider?

tangerineowl

Not sure if technically 2x or 1x crank (You'll see online the standard 2x Easton ring sizes that come with this crank). Normal spider. 68mm shell.

I have to do more reading on understanding chainline setup better, I'm afraid. Did tweak the small ring poz with a spacer so I could drop into smallest cog without chain hitting large ring (don't do that often though). Minimal drivetrain noise to speak of; runs fine for me.

mstateglfr 

Why not just use a 46/30 crank with an 11-36 cassette?

24/28 with 40mm tires is 23.77 gear inches.
30/36 with 40mm tires is 22.94 gear inches.

This would give you a 46t ring to still use for flat/rolling/downhill riding.
An Ultegra GX or a 105 rear derailleur thats mid-cage(GS) can handle this setup as its 40t total capacity.

tangerineowl

Because if I were in the big ring on the flats I would be in the second half of the cassette where the jumps are bigger around the two/three main cogs I'd be.

With my setup I can stay in the big ring quite a lot with slight cog jumps. Dump into small at steeper stuff and when casually exploring off road.

I'm fine with coasting once gears run out. Any faster and I will miss that interesting thing over that way 🙂

xroadcharlie

I have the Shimano 7 speed 14/34 Megarange freewheel on my Giant Sedona and a 28/38/48 chainring. My first thought was the 24 -- 34 freewheel step was a waste of a cog. WAY too much of a gap.

Then I realized why Shimano came up with this. This is the best way to properly space the 6 most important gears I use and still have a super low gear (21 gear inches) with just 7 speeds with either the 28/38/48 triple chainring my bike came with or a 46/30 double chainring.

I don't know if a freewheel will work with your bike. Perhaps someone makes a cassette with the same principle as Shimano's Megarange. You might be able to assemble one yourself or adapt one. It has it's merits if we want a wide range and all but 1 gear properly spaced when we only have 6 - 8 gears to work with on the back.

hermanchauw

The simplest one size fits all would be 22-32-44 front. 44x11 gives 108 gear inch. Plenty. If you don't like to use the 11t, you can go for bigger 28-38-48 or anything in between. Some tourists use 22-36-48.

For 2x with 64/104mm bcd, the smallest is 22 front.

11-42 can be used with 2x or 3x. I haven't done it but there are people who do. 28-38-48x11-42.

I had used 22-32-44x11-32. Top photo.
Now using 26-38x11-40. Bottom photo.

rumatt

Thanks. What 64/104 bcd crank do you have there? Trying to figure out what my options are.

hermanchauw

Interesting. My high gear in regular use was 44x13, giving 91.4 gear inch. Now using 38x11 top gear, giving 93.3 gear inch.

hermanchauw

These are Suntour XCR. Any standard mtb triple cranks can do. Even newer ones like 58/94mm bcd ones. But older square taper would be more flexible as you can easily adjust the chainline.

rumatt

So I'm just realizing that my old XT mountain bike cranks have the same spindle length and will fit? Holy crap I didn't know that. I'll experiment with some of them later today to see if it works.

Some say tiny chain rings don't work with will normal derailleurs because the diameter doesn't match the arc of the derailleur. If that's true, a 46/30 crank with an 11-40 cassette might be the ticket. I just hate the idea if the rear not shifting perfectly.

hermanchauw

It will fit. Just need to adjust the chainline, if they are different.

mstateglfr 

I was asking the OP why they don't just use a 46/30 with an 11-36, but fair enough. Your explanation makes sense.

rumatt

Well I mounted the XT crank with 42/26 chainrings. I can go smaller than 42 because I can't lower the derailleur any further without it hitting the chainstay.

I got it to shift just fine, however the spindle is just a smidge too long. Dammit. I guess I need spacers or a different BB? Hrmpf.

Pic below shows the gap with the crank arm fully on.

rumatt

I already have an 11-34, so 2 more doesn't do all that much.

I could also do 11-40. But I figured if I have to swap the crank anyway I might as well not mess an unsupported cassette range. Although enough people are saying it works well maybe that's a non-issue.

mstateglfr 

2 more on the back and 4 less on the front = lower GI than the other combo mentioned earlier.

Take it or don't, there is no wrong approach to making gearing work.

hermanchauw

Definitely needs a spacer.

Elvo

I have a 48/32 with 11-36 in the back. Works great

wsteve464

[QUOTE=rumatt;21520829]Well I mounted the XT crank with 42/26 chainrings. I can go smaller than 42 because I can't lower the derailleur any further without it hitting the chainstay.

I got it to shift just fine, however the spindle is just a smidge too long. Dammit. I guess I need spacers or a different BB? Hrmpf.

Pic below shows the gap with the crank arm fully on.

QUOTE]

MTB cranks use a 73 mm wide bottom bracket road cranks use a 68mm wide BB. you can probably buy them on line 2.5 mm each. Or buy a new BSA bottom bracket that comes with the spacers. With out seeing the clearance you have you can probaly install an mtb front derailleur that has a shorter arm and a smaller radius to be able to go with smaller chain rings.

aaronmcd

My new gravel bike is 1x11-42. That range is wider than my road race bike with 50-34x11-28. I prefer the larger gaps between shifts. The difference is only a few RPM, and I'm not racing. I can slow down or speed up or change my gearing and be within 2% of optimal everything. I prefer the large jumps in shifting because it's easier to quickly shift when the terrain changes, and dirt terrain can change suddenly and drastically.

Happy Feet

My fat bike came stock 36/22 with a 10 speed 11-36. SRAM X5 long cage derailer.
I swapped the cassette out for an 11-40 without modification.