Yet another gearing thread... ooof i know

[ridethecliche]

Woo! Another gearing thread!

So I'm trying to make a Giant TCX Advanced SX frameset (Cross bike) function as a do everything bike, i.e. road and gravel, and I'm at a bit of a loss when it comes to properly gearing things.

The current setup is an 'old school' 2x11 shimano hydraulic setup with RS685 levers and RS785 brakes. Currently has an ultegra RD and a 105 FD with 11-32 cassettes. I swapped rings on the ultegra cranksets rings to 46/34 which has been awesome, but I caved and bought a GRX 46/30 crankset to get more low end.

I guess my question is about cassettes. I'll post a link that I've been looking at a bunch in terms of options. Link: https://road.cc/content/feature/how-..._tabs=0&page=1

According to the link, it's feasible to run an 11-40 cassette with a stock shadow ultegra/105 rear derailleur. That sounds like it might be great for gravel use but crummy for road use.

I have two sets of wheels for this, one running slightly knobby gravel tires and the other currently running road tires. Would it make more sense to swap them both to the SRAM 11-36 or to swap the road setup to 11-36 and the gravel setup to 11-40 and set the chain for the gravel setup?

With the change in crankset to 46/30, I basically get one more gear out of the 11-32. With the swap to 11-36, I'd get 2 more lower gears... With 11-40 I'd have 3 more.

I'm a bit reticent to do something that's going to be more likely to break everything, so part of me is debating if the 11-40 is even worth consideration.

Anyone have any feedback for what you've done that works? Sorry for the long winded post but...

[raisinberry777]

11-40 is going to be very low - are you doing loaded packing in hilly areas?

With a 46/30, the 11-36 should be sufficient for most hilly off-road riding if you're only carrying small loads (i.e. no camping/cooking gear). In any event, the chain should be set for the cassette with the smallest gearing.

[Alistair]

I’m running a 33/46 crankset with either 10-33 (road) or 10-36 (gravel) cassettes. Works great here on the East coast.

The bike had a 30-43 which was too low. I have that spider/ring combo in my parts bin just in case I go somewhere I need the range, or bike-packing, but usually use my maintain bike for those rides.

I doubt I’d bother with anything lower than the 36 since you have the 30t small ring. Unless you’re planning g to be heavily loaded or seriously under-biking.

[tellyho]

I have the GRX crank with 11-36. For me, that "2 more teeth" in the rear is really all I need for climbing.

In an extreme example, I have a 26/46 x 11-28 setup on my fast gravel bike that really is a double 1x. Plenty of low for trails, plenty of high for asphalt.

[ridethecliche]

Originally Posted by raisinberry777

11-40 is going to be very low - are you doing loaded packing in hilly areas?

With a 46/30, the 11-36 should be sufficient for most hilly off-road riding if you're only carrying small loads (i.e. no camping/cooking gear). In any event, the chain should be set for the cassette with the smallest gearing.

Smallest gearing as in the one with the smallest 'big' cog right? So if I have an 11-32 and an 11-36, it should stay set for an 11-32?

I'm not doing much loaded touring (or any honestly), but that's the long goal. I just want to have the option of staying seated in certain parts of the rides I'm doing.

I honestly feel like just that 30 ring is going to make a huge difference, but I really want to put on a new chain when I go to install the crankset and would rather just swap cassettes all at the same time.

Originally Posted by Alistair

I’m running a 33/46 crankset with either 10-33 (road) or 10-36 (gravel) cassettes. Works great here on the East coast.

The bike had a 30-43 which was too low. I have that spider/ring combo in my parts bin just in case I go somewhere I need the range, or bike-packing, but usually use my maintain bike for those rides.

I doubt I’d bother with anything lower than the 36 since you have the 30t small ring. Unless you’re planning g to be heavily loaded or seriously under-biking.

That's really helpful advice. I'm honestly wondering if I might have to sway the big ring to a 48 for dual duty use... Not sure how a 48/30 would work but might be worth a shot.

Options were a bit limited since I was looking for a 165mm crankset. I could still get the bikingreen rings and convert a 165 ultegra crank I have to 48/31. Do you think that would be a better option? I'm not opposed to selling the GRX cranks I bought... I'm sure I wouldn't lose much if any money on them. I was just worried about the bikingreen rings having meh shifting but they've been reviewed pretty well on here so maybe I have nothing to worry about.

Originally Posted by tellyho

I have the GRX crank with 11-36. For me, that "2 more teeth" in the rear is really all I need for climbing.

In an extreme example, I have a 26/46 x 11-28 setup on my fast gravel bike that really is a double 1x. Plenty of low for trails, plenty of high foar asphalt.

Holy heck, that works with your FD?

Do you think something like 48/31 would be better for a dual duty bike?

[Alistair]

46x10 is plenty high gear for me. It does get used but really only on fast descents on group rides. 46x11 would probably be good enough but SRAM is all in on the 10t cog.

46x11 on 38mm tires is a hair over 30mph at 90rpm.

[ridethecliche]

Originally Posted by Alistair

46x10 is plenty high gear for me. It does get used but really only on fast descents on group rides. 46x11 would probably be good enough but SRAM is all in on the 10t cog.

46x11 on 38mm tires is a hair over 30mph at 90rpm.

Yeah, I think the 48 would net me maybe 1.5mph? I can spin at 120rpm for a few if I really have to...

I also looked at my current setup. The bikingreen rings might make the chainline a bit sketchy since I already have a couple of small spacers between the bb and the crank to move things out given the NDS power meter. I have like maybe 1cm of clearance between the big ring and the chainstay and that would drop a bit with the inboard movement of the bikingreen rings.

Bummer because using the ultegra setup would save more than a quarter pound, but that's hardly what matters most here! I'm actually going to be using a 105 or DA NDS arm with the grx crank for the powermeter which is going to be kind of hilarious haha.

Would the chain length here be set for the 11-36 or 11-32 cassette with the same cranks? 11-36 right?

I'd consider moving both setups to the same cassette but 30-36 on the road seems a bit mental and I'd likely miss some of the in between cogs.

[tellyho]

Originally Posted by ridethecliche

Holy heck, that works with your FD?

Do you think something like 48/31 would be better for a dual duty bike?

I was as surprised as you. It was a bit of a break-all-the-rules build, including crimping 853 chainstays to fit 650b. But the 26/46 shifts absolutely fine with a DA FD from the 10 speed era. I have a chain catcher on there just in case, but I ride gravel on the bike with no issues. Upshifts are not lightning fast but always get there.

Unless you're planning on climbing big hills, I think the GRX crank (either the 600 level 46/30 or 800 level 48/31) would be fine with an 11-32 cassette, giving you smaller gaps between gears.

[ridethecliche]

Originally Posted by tellyho

I was as surprised as you. It was a bit of a break-all-the-rules build, including crimping 853 chainstays to fit 650b. But the 26/46 shifts absolutely fine with a DA FD from the 10 speed era. I have a chain catcher on there just in case, but I ride gravel on the bike with no issues. Upshifts are not lightning fast but always get there.

Unless you're planning on climbing big hills, I think the GRX crank (either the 600 level 46/30 or 800 level 48/31) would be fine with an 11-32 cassette, giving you smaller gaps between gears.

Thank you!

I just ordered 2 x 11-36 cassettes for gravel use and will use the 11-32 for the road! Looking forward to having that low gear sorted. This is going to be fun!

[merlinmurph]

Late to the party....but I have what you're getting

46/30 GRX crank
11-32 for road wheels
11-36 for gravel

Suits me fine, but I am on the older side. Gearing is so personal....

Enjoy your ride

[ridethecliche]

Originally Posted by merlinmurph

Late to the party....but I have what you're getting

46/30 GRX crank
11-32 for road wheels
11-36 for gravel

Suits me fine, but I am on the older side. Gearing is so personal....

Enjoy your ride

I'm 34 but have back and knee issues. Starting to rehab the knee but want to have a bailout on hills because the name of the game is longevity. I've had to quit riding every time I've tried in the last 15 years since the original knee issue in college. Forced me to stop racing. I'm just trying to keep it happy for now while I start seeing pt and doing pre/rehab for it and figure out what's wrong!

Thanks for the input! I'm stoked for the versatility of this combo!

[br0qn]

Originally Posted by merlinmurph

Gearing is so personal....

and bike dependent, no?

i've been riding my voodoo (crossbike) with 44/29 rings and an XT 11-40. when setting up the drive train my priority#1 was some range while maintaining a 20" bail out gear as this bike is doing climbs on dirt but I didn't want to spin out too quick bombing pavement. this gearing has worked out great for this bike.

i've just finished building the rb-1 with 53/39 rings and a 12-26 cassette which yields like a 40" low gear...massive difference but doing the harder climb on my usual paved route which has some 13% ramps I was super surprised how I managed. The bike weight differential isn't that much, ~2 lbs or 10% . the climb was harder for sure on the rb-1 but it showed me that it is a far more efficient climber at the least. if the rb-1 was geared the same as my voodoo the bailout gear would have felt crazy low.

anyway, long winded way of saying there are so many variables to consider when talking about these things, among them is your bikes geometry

re the OP/your case - have you played with the gear inch calculator?

[TheseGoTo11]

Originally Posted by ridethecliche

I swapped rings on the ultegra cranksets rings to 46/34 which has been awesome, but I caved and bought a GRX 46/30 crankset to get more low end.

According to the link, it's feasible to run an 11-40 cassette with a stock shadow ultegra/105 rear derailleur.

Also late to the party, but wanted to share my experience. On what I consider my 'winter' bike (fenders, 35mm tires) I've got an Ultegra crank with 46/34 rings, 11-40 XT cassette and unmodified R8000 GS rear derailleur (i.e. no Roadlink, etc). This shifts wonderfully. FWIW, the lowest ratio on this is .85 vs. .83 with the 46/30, 11-36 combo. So, marginal difference in gear range. However, the 12 tooth difference between chainrings is much different than the 16 tooth difference with 46/30, which means one or no shifts required on the rear to "recover" the gear when switching rings.

[ridethecliche]

Originally Posted by br0qn

and bike dependent, no?

i've been riding my voodoo (crossbike) with 44/29 rings and an XT 11-40. when setting up the drive train my priority#1 was some range while maintaining a 20" bail out gear as this bike is doing climbs on dirt but I didn't want to spin out too quick bombing pavement. this gearing has worked out great for this bike.

re the OP/your case - have you played with the gear inch calculator?

That sounds like a pretty awesome setup!

I don't usually look at gear inches. I usually look at speed at a certain fixed rpm when switching gearing stuff. Just helps me see what the actual change will be. I'm mostly thinking from a seated pedaling perspective not a 'can i power up this' one.

Originally Posted by TheseGoTo11

Also late to the party, but wanted to share my experience. On what I consider my 'winter' bike (fenders, 35mm tires) I've got an Ultegra crank with 46/34 rings, 11-40 XT cassette and unmodified R8000 GS rear derailleur (i.e. no Roadlink, etc). This shifts wonderfully. FWIW, the lowest ratio on this is .85 vs. .83 with the 46/30, 11-36 combo. So, marginal difference in gear range. However, the 12 tooth difference between chainrings is much different than the 16 tooth difference with 46/30, which means one or no shifts required on the rear to "recover" the gear when switching rings.

Man... was this a missed opportunity then? Maybe I should have just stuck to the current setup with an 11-40 XT cassette? I think that would have gotten me most of the way there and would have required changing so much less!