Originally Posted by bonsai171

As stated in the original post, it will mostly be used for gravel, and some bikepacking. If I had to put numbers to it, the gravel would be maybe 90%, and 10% bikepacking. That being said, we live in a semi-rural part of Georgia. In our backyard is access to some chunkier gravel riding/singletrack. It would be fairly easy to do 60-80 miles of riding (with a decent % being gravel) just leaving from our front door. Terrain is moderately hilly-most rides consist of at least 2000 ft climbing, sometimes as much as 4000 ft. Going further north into the Cohutta mountains would mean even more gravel and more climbing 10-15% climbs aren't that unusual there. Could easily climb 6,000-10000 ft there. There is a climb in the Cohuttas I did last year which took over an hour to complete, and 30 min just to descend! Haven't seen too many bikes that come stock with enough gears, and the ones they have seem to be more for regular gravel (higher gearing). This is why I'm planning to build something. The more expensive bikes tend to be 1X systems too, which for me, is a negative.




Dave

Originally Posted by bonsai171

Looks like the min low sprocket is 40t (not 36t).

https://bike.shimano.com/en-NZ/produ.../RD-RX812.html

Back to the drawing board.

Originally Posted by wsteve464

I believe you can use an MTB Di2 rear derailleur with GRX components and it goes up to 42 teeth on the rear with no problem.

Originally Posted by bonsai171

Looks like the DI2 GRX derailleur would work too. Unfortunately the derailleurs cost a small forture. Had another idea. There is an SLX crankset with 38T/28T (SLX FC-M7000-2) which will work with a 11-42 cassette. That combo would yield ~17-18 gear inches. Is there a front derailleur, rear derailleur, and set of hydraulic STI shifters that would work this this combo? Could be a winner.

Dave

Originally Posted by TimothyH

Additional GRX information...

https://www.youtube.com/watch?v=D79XP74K6KA

Originally Posted by bonsai171

The dropper post sounds interesting, but I always thought of it as more of a single track thing. Maybe it would be good for going over washboarded gravel?

Been thinking about the whole drivetrain dilemma too. Might even be better to go 1x the way GRX is now. Would it be possible to change the chainring on a grx crankset to a 32 t narrow wide chainring and then use a 11-42 cassette? Think the gearing would actually work as far as getting sub 20 gear inches. c'mon shimano, you're not making this easy :-p

Dave

Originally Posted by bonsai171

I'm in the beginning stages of planning the next gravel bike. It will be used for multi-surface rides and eventually bikepacking, but I also have a dedicated road bike for regular road duty. Been looking at building up a bike from scratch, and need some help deciding between a GRX groupset and a 105/Ultegra mix. I would like a clutch rear derailleur, so that will be either Ultegra or GRX. The big question is whether GRX would be worth it (suspecting it will cost more than a 105/Ultegra mix) or if I can save a few bucks and skip GRX.

So far I speced out a Niner RLT 9 steel with a GRX groupset (46/30 crankset, and 11-36T cassette) which came out to 3k. Also found Excel sports has a Niner RLT 9 RDO already built with Ultegra for 3K. Haven't really decided on a budget for this bike yet, but some input would be appreciated on whether to go with GRX or 105/Ultegra. Maybe some other frames to look at would be helpful (also saw the Jamis Renegade which might work but is a similar price to the Niner RLT 9 steel frame).

Dave

Originally Posted by Metieval

hope you didn't do anything yet....

this is exciting!

https://gravelcyclist.com/bicycle-te...learance-more/

Originally Posted by Metieval

hope you didn't do anything yet....

this is exciting!

https://gravelcyclist.com/bicycle-te...learance-more/

Originally Posted by bonsai171

Saw that a few minutes ago! Looks like the biggest change is the max tire clearance of 50mm. I recently switched my old 30lb bike from 2 inch knobby tires down to 1.75" semi-slicks, and noticed a big difference in speed. The tradeoff here is in comfort a little on washboarded roads. Tempted to put the 2 inchers back on lol. Maybe if they had just the right tire pressure?? It is a bit like driving a tank. Don't worry too much about line choice with those lol. I would like to find the perfect balance of comfort vs. Speed, esp for those longer rides that include some single track. The only thing I can think to do is mess around with tire pressure on the 2.0s and leave it, (or leave the semi-slicks on) or set the pressure high on the 2.0s and drop it for the single track, and then bump it back up.

Maybe a big reason why I feel like the 2.0s are slow is the 30lb bike weight too.

Dave

Originally Posted by Bryan C.

I have an 2x system on my Giant, 46/32 FSA front and 11-40 rear. I found that set up to be pretty solid for similar terrain. If you are a strong rider that should give you a pretty good base to work from.

My opinion is just get the 105 and the rx, then spend the extra money on a nice carbon wheelset.

Originally Posted by ms_2020

Hello Bryan. It's been a year so no idea if this will reach you. If it does, I'd greatly appreciate your experience with this setup. I am planning the same for my 2020 Grade, which has the R7000GS derailleur (39T capacity) and the FSA Omega Adventure crankset. I will use the Sunrace 11-40 and change the inner ring to 32 because it reduces the chain wrap to 45T and I don't much like the 16T drop in front. My questions, if you don't mind:

- Does this require a Roadlink? If so is it the DM version?
- Does this require a 1.85mm spacer behind the cassette?
- Will a clutched derailleur (RX800 or GRX810) be necessary to deal with the slacker combinations?

Thanks a lot.

Originally Posted by ms_2020

Thanks very much for responding Bryan. I don't mind the trial and error and have a new chain ready to go. Expecting to need 116 links. The current cassette is 11-34 (11-speed road) for the R7000. The chainset is 46/30 now but like you I plan 46/32. I'm doing this to reduce the front gap to 14T and the total overcapacity to 4T. I ordered a 2mm spacer so can fix a difference in cassette size if needed, as well as a new chain so I can add 2-4 links as needed for the big-big. My main curiosity is how you ended up - successful? Are you still using 46/32 and 11-40 (with RX800?) without problems? If so, is this without a roadlink? I'm not a very experienced mechanic so just checking with others who may have the right experience and be able to help me avoid mistakes. Appreciate you getting back to me.

Originally Posted by RadDog

For me, if you are OK with a 2X then you can't beat Ultegra for the money. IMO, the reason to go GRX is for the 1X option. I prefer 1X for off road. I believe that at the 600 level the GRX quality starts getting good, I think the crank arms on the 600 are carbon (although I could be wrong). I have 2X Ultegra on my road bike and the front derailer creates problems and is just messy. However, for bike packing you may need the granny gear.

Originally Posted by RadDog

I think the crank arms on the 600 are carbon (although I could be wrong)

Originally Posted by Seattle Forrest

This is unrelated to the topic of the thread, but may be of interest to bike packers willing to spend on comfort.

https://zpacks.com/products/plexamid-tent

That's the lightest solo tent available with bug mesh etc. It's waterproof, roomy for one person, packs small, and comes in under a pound. PCT thru hikers attest to its quality and durability.

Originally Posted by TimothyH

My opinion is that the deciding factor is going to be low vs high gearing.

Assuming only Shimano supported configurations, GRX is going to support a slightly lower gear which will help when hauling tents, food and sleeping bags on hilly or mountainous terrain.

Ultegra will be higher geared for go-fast rides. Climbing the really steep stuff up in the Blue Ridge or Cohutta Mountains will be difficult however.

Going beyond Shimano supported systems, there is no doubt that I'm slower with the 46/30 ultra compact cranks than I was with Ultegra 50/34 compact road cranks but there is now way I could haul camping gear on repeated 5000 foot days without the very low gears. In fact, I don't think GRX is really low enough for bikepacking in the mountains. My low gear is 30f/42r or about 19 inches and it is nice. GRX and Ultegra are in the mid and high 20 inch range.

Once you start hauling 35 lb gear up in them hills you will likely need a very low gear.


-Tim-

Originally Posted by MichaelTapp

Hijacking this thread because I have a similar question, with a bit of a twist. The 2x GRX 810 that I ordered isn't going to be available until March. But the bike supplier said they could put Ultegra groupset on it with the grx rear cassette.

My only hesitation is the gear ratio. From what you can put together do you think I would still have an easy gear on the ultegra(with the different rear cassette) in case I am schleping gear up a mountain road? From time to time I will be doing bikepacking with gear. Overall I'll be riding 80% roads and 20% off road. Any thoughts will be well appreciated!