bonsai171

Hi,

I recently bought an Apex 1 Salsa Warbird, and would like to put some lower gearing on it. The low gear is 27 gear inches, and I'm thinking low 20's would be better. I ride in very hilly areas, some of the grades are 10-15%. The only way I can see to do this is to switch to sram eagle, which would mean swapping the entire drivetrain. It looks like sram gx eagle would work, but I want to make sure. They make a non-boost crankset, which would mean a 45 mm chainline (which is good for my 142 mm rear wheel). The cassette would be a sunrace 11-50, since it is a hg interface (gx is sram xd). I will have to run a 12 speed shifter with a Paul 31.8mm adapter, and the original brake levers and calipers would stay the same. Does it sound like this will work? Only potential downside I can think of is the different q factor of the crankset (running the Apex 1 crankset now). Thoughts?

Dave

shoota 

Any reason you can’t just put a smaller chainring on?

bonsai171

Im currently running a 42 tooth chainring. The smallest possible chainring is a 40 on the Apex crankset. That would decrease the gear inches from 27 to 26. Not much of a difference. Would have to change the crankset at the very least to make a significant difference in gearing.

​​​Dave

trailangel

No mention here of 11 speed or 12 speed. I'm guessing 11 speed. Hey, just put on a new cassette 11-46 or 11-50...... you are the one to see if it will work... rear DR can handle it.
Isn't SRAm eagle 12 speed with a 10 tooth cog on the rear? Now you are changing shifters and the rear freehub or even the rear hub itself.

Or, like said above, put on a smaller chainring if you can.


And if I might speak frankly....if I can't do it with a 1 to 1 gearing or just the next step lower... mid 20s or upper 20s gear inch, I get off and walk. I have no shame in saying so. I walk and enjoy the view for 20 minutes or so then get back on and do some more riding.

HTupolev

The most minimal change that would create a substantial difference would be to try throwing an 11-50 11-speed cassette on the bike with a longer chain and see if it just works, and if not, toss a hanger extender at it. That will most likely produce something satisfactory. The drawback being that if it doesn't work, you're out some cash.

​​​​​Why is this a common response to gearing bottom-out? With any other solvable mechanical or fit issue that might force someone to get off their bike, you almost never see people recommending that the rider just deal with it.

trailangel

Hey, I'm just saying this is what I do, I'm not recommending the OP deal with it the way I do.

Never before have I seen so many bikes with such low gearing. 46...50... on the rear, I thought those would be for the front. And yet riders still want lower gears. .... and then want at least a 115 gear inch for downhill.

DeadGrandpa

I'm not sure if it will fit your BB, but I know that a SRAM Force crankset has a direct bolt on chainring. I bought a 32T chainring to swap out the 42T that came on the bike, and another chain that is 5 full links shorter to go with the swap. For use in the mountains. The cassette is an e-13 brand, 9-46 teeth. Seems like a solution, but maybe not the least expensive.

Bob the Mech

So you are floating the idea of converting from Apex 1 to Eagle GX (the NX range is $250 less than the GX and does the same thing by the way). Egale is the MTB groupo, 12sp rear shifter is flat bar mounted.

So you will not be replacing your Apex 1 11 speed shifter with a 12 speed SRAM road shifter. You will be adding the flat bar Eagle 12 speed shifter to the set up and disconecting / removing the gear cable from the Apex 1 shifter and fitting an Eagle rear mech to use the Sunrace 11-50 12 speed cassette...I am I right so far...?

Or you could replace the the 42 tooth chain ring with a 40 tooth and see if that works for you. Cost wise and time wise, an easier first step soloution...

Just worked out quickly these values:

C' Ring/ Cassette cog

42T/ 42T on 700c with 47c tyres = low 28.2"
42T/ 42T on 650b with 56c tyres = low 27.4"

40T/ 42T on 700c with 47c tyres = low 26.86"
40T/ 42T on 650b with 56c tyres = low 26.1"

42T/ 50T on 700c with 47c tyres = low 23.69"
42T/ 50T on 650b with 56c tyres = low 23.02"

40T/ 50T on 700c with 47c tyres = low 22.56"
40T/ 50T on 650b with 56c tyres = low 21.92"

These low gear values will get even lower if you run tyre sizes under 47c...

As a note:
40T/ 11T on 700c with 47c tyres = high 104.36"....which means you will start to spin out before hitting 30 mph with your legs hammering out 120 rpm...

So yes get the Sunrace 11-50 cassette in 11 speed to match your Apex 1 shifters. Get the CSMX80, CSMS7, CSMS8 or CSMX8 (11,13,15,18,21,24,28,32,36,42,50). Some of these models are even available as 11-51, 11-46 or 12-51. Then get the Sram X-Sync Asymmetric Apex 1 40 tooth chain ring...Job done. No need to change any thing else...

Only issue I can see is the Apex 1 rear mech is officially rated to a MAX 42 tooth cassette cog. It may work...but no promises... If not some thing like SunRace SP570 Rear Derailleur Extended Link or the Wolf Tooth Direct Mount Roadlink is required.

HTupolev

Bicycles have historically often had very badly inadequate bottom-end gearing. Being forced to get off and walk is far beyond the failure point; being forced 20, 30, 40% below your self-selected cadence can have large repercussions for both power output and fatigue. Not caring about that sort of thing is comparable to not caring that somebody duct-taped a 10kg weight to your bike.

The size of the rear cog by itself also doesn't tell you how low the gear is. The OP's gravel bike has a 42-tooth chainring, and can only go a couple teeth lower on their current cranks; my gravel bike only has an 11-32 cassette, but because of its 24-tooth small ring, my lowest gear is considerably lower than an 11-50 would offer on the OP's bike (.75 ratio versus .82).


So? The low gear that a rider has use for does not, by itself, tell you much about how much top-end they have use for. Even quite strong riders might make extensive use of sub-20" gears if they're tackling serious mountainous climbs; if they're also using that bike in road pacelines where someone is hammering shallow descents at 40mph and you need to keep a bit of power flowing through the pedals in the draft, that 115" gear is what's keeping you from having to spin above 120rpm.

Koyote

I’m with trailangel : if I can’t ride it with a 1:1 gear, I get off and push. I’ve tried even lower gearing, but on rough, rocky, tree-rooted trails, that has me moving so slowly that I might just bump into something and tip over.

Bob the Mech

40T/ 11T on 700c with 47c tyres = high 104.36"....Ofcourse this will be lower for smaller volume tyres...

There is the theory that if you're getting close to a walking pace while riding it's more economical to get off and walk...just like riding a fixie

MAGAIVER

The easiest way of getting more range in your bike imo would be to use a Sunrace 11-50 11 speed cassette and swap your rear derailleur cage with an MTB one or use a full MTB rear derailleur with a Jtek Shiftmat, thats the most elegant solution as well so you can keep using your double tap shifters.

bonsai171

Sounds like you have the just of what I want to do, but not quite. I'd rather run the 12 speed eagle shifter with the eagle rear derailleur than try to make the Apex shifter work with a 50t cassette. My buddy broke 2 di2 derailleurs trying to get a derailleur to exceed the spec. As it turns out, the cassette I'm running now is the 11 speed nx 11-42. Haven't heard a lot of good things about the nx drivetrains, so I'm leery or trying them. Plus the components are pretty heavy. The cassette is 529g by itself.

Dave

HTupolev

It's occasionally more economical on a fixie because you're likely very badly bottomed out at that point. As long as the gearing is reasonable and the circumstances remain reasonably rideable, it's just about always more economical (and faster) to ride.

There's also the issue of what "walking pace" means. A 42-50 ratio on 40mm 700c tires is ~4.8mph at 70rpm. 4.8mph is very brisk for a "walking pace" even for an unladen person on flat ground: for a cyclist rolling a bicycle up a super-steep gravel road, it can be an intense effort!

dsaul

Absolute Black makes a 38t oval chainring for the Apex1 crankset. https://absoluteblack.cc/sram-apex-1...s-38t-premium/

bonsai171

That looks like a good option. I might have to do one of my super hard rides with lots of climbing on the 42t to get a baseline. In the past I had 22gi (different bike). The 38t will get me pretty close to that at 24.87 (vs 27.6gi with the 42t). How do you like the oval ring vs. round?

Dave

dsaul

I'm a fan of oval chainrings for climbing, because it makes it easier for me to maintain a higher cadence. I have a 34t oval and a 48t round ring on my main gravel bike and that provides a unique insight into the difference in feel between the two. I don't notice any difference when I change from the round ring to the oval, but there is a lumpy pedaling feel when I switch back to the round ring. That feeling only lasts a few seconds, but there is a definite feeling that there are hard spots in the rotation on the round ring.

The other benefit of the oval rings is less tendency to lose traction on the rear tire when climbing loose gravel/dirt. I have a 1x drivetrain on my other gravel bike with a 40t round chainring and I definitely notice that the rear wheel breaks loose on some climbs, where it doesn't with the bike with the oval ring. I plan to put an oval ring on that bike soon.

dwmckee

Several months ago I dropped 2 teeth on my front chainring and it wa instantly like conditioning after a month of training! I was able to climp at a more sustainabel cadence and was not toast at the top. The net was I picked up speed on my overall ride as well and did not feel as cooked at the end of a ride.

scubaman

+1 for the recommendation to start with a smaller front chainring. My buddy and I just did a week of bikepacking on hilly gravel roads (up to 15%) using 36 tooth round chainring with 11 speed 11-42 cassette. We're normal riders, definitely not crazy strong, and we were both able to pedal up every hill. For future trips, we might use 34 tooth chainring and/or 11-46 cassette. If those gears weren't enough, I'd get off and push, as others have written.

The only thing we gave up with smaller front chainring is the ability to hammer downhill - which I have zero interest in doing anyway.

bonsai171

On Saturday I did a ride with 5000 ft of climbing. Some of the grades topped out at 20% It was a bit of a grind. Average cadence was 66, which is low for me. Average speed was 8.9 mph.

A typical ride is 95-100 rpm. Is there a way to figure out what chainring is needed to get me to 95-100 rpm on a ride like this? Currently running a 42.

Dave

scubaman

There might be tools that can estimate this, but they’d also need to factor for weight (bike + rider) and the rider’s power. The guides I’m aware of, such as on Wolf Tooth’s website, don’t do that.

My general recommendation is to choose a 1x chainring based on the most difficult gear you don’t want to be without. For how I ride, I don’t need my gravel/bikepacking bike to have anything harder than 36 x 11 (and I expect I’d be fine with 34 x 11 most or all the time; the friend I ride with most often has that, and he’s stronger than I am). That gives me an easiest gear of 36 x 42, and I could have 36 x 46 without changing anything on my drivetrain except the cassette.

If you need to be able to hammer down hills, or keep up in a fast pace line, and also want to be able to spin up 20 degree hills with the same bike, you might be better off with a subcompact 2x drivetrain than with 1x.

trailangel

https://www.sheldonbrown.com/gear-calc.html

fietsbob

Need a different crank set ,,, Mountain, compact, the Big chainring is the 42t.. small is 22t.

bonsai171

That's the plan. Going with something direct mount, maybe Sram force since I have a press fit gxp BB already installed on the bike.

Dave

fietsbob

Had a Mountain tamer Quad for a 4 chainring crank (to try it out, in the 80's) 46-36-26-16.. 13-28 freehub cassette..

16:28 .. that was Low..