xroadcharlie

Looks like a fine choice to me. You will likely need a new rear derailleur with the extra teeth though, which might mean a new shifter as well.

This would give you a low gear of about 31 gear inches. That's about 5 mph at 55 rpm. That's pretty low and might be adequate for either short, fairly challenging hills, or longer more forgiving ones.

My comfort bike has 2 very low gears. I've tried both the 21 and 30 gear inch sprockets and found even on a short, but challenging gravel hill the 21 GI is almost too low. The 30 GI sprockets are more effective overall. If it where on a long ride on a challenging hill I would want less then 30 though. The 46/30 chainring with a 13 -36 cassette would get you about 22.5 GI. If you need lower gearing then the chainring change alone brings alone this or something close should do it.

woodcraft

Setting up a bike similar to OP (see post #21), & got Bikini Green 46/30 chainrings up & running,

with 11/36 cassette, Force medium cage RD (which I had on hand), and Roadlink.

After a few rides including a 2k climb yesterday: shifts well, 21.6 G.I. low lowers HR and improves traction in steep & loose conditions, and quality of the chainrings looks good. Didn't even have to change the chain length.

Only mis-step is that the crank has hidden bolt behind the arm, so the chain-drop stud is not behind the crank where it should be. I may get a lighter crank so will leave it, but it could be drilled out,

& doesn't seems to be a problem as is.

dpicare26

Just thought I would update. I made a few considerations based on the feedback I got here. Decided to change RD to a 9 speed Deore, and swap cassette for 11-36t (and new, longer chain). Also swapped the 32mm tires for 42mm.

The RD sounded noisy on the work stand, but on an actual ride today, was very quiet and shifted perfectly.

Thanks all for the feedback.

dpicare26

Sorry to revive an old thread, but my question does not warrant it's own thread.
I rode a season with the above setup, and it was fine for 90% of the riding that I do. I still think I want to go compact on my crankset. I've got my roadie with 52/11 where I can hammer the pedals and go fast, and I want my gravel bike to have super low range for climbing. I'm interested in doing some events like Keystone Gravel, or UnPAved, which have routes like 80 miles and 8,000 ft, or 110 miles and nearly 10K feet.
Where I get tripped up, is determining what all the verbiage about the bottom bracket compatibility means. My current crank is Shimano DA FC-7800 (which Shimano says works with 68mm and 70mm BB).

I've thrown around ideas of the Shimano GRX above, but not so sure I also want to replace the FD.

What should I be looking for as far as BB compatibility in the description? I've been looking at this FSA Crankset

mstateglfr 

That crankset needs its own BB as it is not compatible with a Shimano HT2 BB.

This is what you need based on the description, assuming your frame is PF. https://www.ebay.com/itm/265121109796

I have managed to stay away from FSA cranksets, except for square taper models, in part due to all the different BB types they use.

redlude97

One option would be the miche subcompact which works with your HT2 BB so it would be a drop in

https://road.cc/content/review/26520...ouble-chainset

dpicare26

I'd like to keep the BB for sure. It's a Chris King and it's great. I'd never even heard of an HT2 BB before. How were you able to identify it as that? Just based on the DA crank?

Edit: Just realized HT means hollowtech

dpicare26

Cheers, that's ideally what I'm looking for. How do you tell it's compatible with a HT2 BB?

redlude97

In the article

Quote:

Graff comes with either 46/30 or 48/32-toothed CNC alloy rings, and slots straight into a Shimano Hollowtech bottom bracket (it doesn't come with its own).

dpicare26

I'm having a difficult time sourcing one of these. Also was reading that some had issues with using HTII BB's and this crankset. I'm still considering a GRX and then possibly new RD.

Any other suggestions for a sub compact crank? Any caveats with using a MTB crank, like Deore 2x10?

mstateglfr 

38/28 is significantly different from a subcompact 46/30 road crankset. Also, you would need to use spacers to fit your 68mm wide bottom bracket shell, which results in the Deore crankset being set further away from the center of the bottom bracket. This will result in a front derailleur that may not index properly, in addition to possibly not fitting the smaller size rings or their more compact curve.


Based on your prior questions as well as suggesting such a different gear ratio from what you otherwise asked about, are you sure you know the chainring combo that will help you?


As for other subcompact cranksets, fsa omega and praxis alba are other options. Not sure if your bottom bracket is pressfit or threaded, it matters.
Maybe bring your bike to a local shop and ask them to source the necessary parts to make the crankset gearing smaller?

Chilepines

I have an FSA Energy modular which is similar to the Omega you are looking at. You would not be able to keep your BB - it is a 30 mm spindle. But getting an FSA BB for it is not a challenge. 46/30 seems to be the new standard for gravel drivetrains, and it makes sense to me.
The problem with Deore is chainlink - the spindle will be longer and push the chainrings outward to match the wider rear axle on MTB. Road chainline is narrower. GRX is (I think) 2.5 mm further out. You will also likely have a problem with the FD with a Deore crank.

dpicare26

I appreciate that. I am trying to learn. And yes I'm also reading 2.5mm offset for the GRX. I was also reading other threads about GRX and FD compatibility. Many people stating that their 105 or Ulterga FD's were able to accommodate 2.5mm offset, with the limit screw maxed, or near maxed out.

Where I'm getting overwhelmed is trying to understand all the different BB types. For instance, the Miche Graff mentioned above, one article states it works easily with hollowtech II BB, but directly from Graff website (as well as other european vendors), this should only be used with a Miche BB: USE ONLY WITH MICHE BOTTOM BRACKETS
EVO MAX 36x24tpi ITA 1,370x24 BSA / EVO MAX 68x46 (BB30) / Supertype 86,5x46 (BB86) / Evo Max 68x42 (BB30) / Evo Max 86,5x41 (PRESS FIT)

So yea I'm all over the place with Deore and Miche Graff and GRX, but really I just want to keep my current BB since it likely cost more than any of these cranksets alone.

I think I'm leaning toward the GRX and just hoping I don't have FD issues.

Chilepines

If you really want to keep the BB you probably need to stay with Shimano. (I can't imagine why you would let the BB drive your decisions, but everyone has their priorities!). Then I think you go with a GRX crank and GRX FD and you should have no problem. New GRX front mech is only $55. I'm running 46/30 front and 11-36 cassette, with a SRAM Rival road RD. That is a really low gear and it's unlikely you need to go as far as a 40 or 42 cassette.

bamboobike4

Seems like the simplest choice to keep that sweet Chris King BB is a compact Shimano crankset for Hollow Tech II, say a 6600/6700/6800. They are reasonably priced abundant you can run a 50/34 for a while to see how it goes. Unless you are climbing on gravel a lot, it appears that will be the improvement you need. You can always drop the 50T down a bit, but 34T is th lowest on Shimano road compacts.

A Wolftooth Roadlink may buy you 4T on the rear, not sure on that bike. It increases the cage drop by 22mm, but not the cage length.