Shimano Gravel Derailleurs: GRX & Ultegra RX Compared
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- เผยแพร่เมื่อ 18 ก.ย. 2024
- #Shimano #GRX #UltegraRX #GravelGears
After I scratched up my GRX 812 derailleur a few months ago I went on a search to see what other Shimano gravel derailleurs are available on the market today. This led me down a Shimano GRX rabbit hole where I discovered all the little details that distinguish the Shimano GRX rear derailleur models from each other. During my search, I also ran into the Ultegra RX range of derailleurs, the predecessor to the GRX derailleurs. With so many options available, all the small differences tend to get a bit confusing. That’s why I decided to get all the information condensed into one video to allow for easier comparisons. My hope is that this information can help save you some time when trying to figure out which derailleur is best for your gravel bike.
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Bike Components Mentioned:
GRX 810 Rear Derailleur: amzn.to/32SCD3G
GRX 812 Rear Derailleur: amzn.to/37OpjfT
GRX 817 Rear Derailleur: amzn.to/2WPsZuv
Ultegra RX 800 Rear Derailleur: amzn.to/32NDC53
Ultegra RX 805 Rear Derailleur: amzn.to/2CNgpW3
11-34T Shimano Ultegra (HG800) Cassette: amzn.to/3jBJzYC
11-34T Shimano 105 (HG700) Cassette: amzn.to/2CMVTVn
11-40T Shimano XTR (CSM 9000) Cassette: amzn.to/32PGFtl
11-40T Shimano XT (CSM 8000) Cassette: amzn.to/30HB3Pj
11-42T Shimano SLX (CSM 7000) Cassette: amzn.to/35BaITf
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The grx 810 can go up to 40t unofficially, just adjust the b tension screw. If you get the wolftooth goatlink and longer b screw you could get it up to 46t.
Thanks for the comment. I figured that there must be a few handy hacks that can help push the limits of these derailleurs. I guess another option might be to fit the Gabaruk pulley arm, which in combination with your b-crew hack could really improve the 810’s range.
Hey, thanks for the video... I have a Specialized Diverge with 105 groupset and I would like to replace the rear derailleur with GRX RX812 (also with M5100 11-42 cassette). My crankset is a Praxis 32-46 and the shifters are 105 2x11. Do you think that I would work fine?
Very clearly explained. Thanks!
Good video there Freddy!
Great! Thanks!
Very informative vid. TQ. I am a newbie. Thinking of upgrade. GRX series were designed for dropped bar. But my bike is flat bar. My question, will GRX RX812 Derailleur able to be matched and worked well with Deore XT shifter?
Glad that the video was informative. Unfortunately this is one of the major limitations with Shimano products. MTB and Road components don't mix well. GRX derailleurs are basically classified as "road" and works perfectly well with road shifters (Ultegra, 105 etc), but not with MTB (Deore XT) shifters. The cable pull is different between road and mtb shifters. Wolf Tooth does make a tanpan product (bit.ly/3BxHCop) that allows you to adapt road shifters to a mtb derailleur, but not vice versa.
You can use Flatbar Tiagra Shifters, there is a Trigger version with the cable pull specified for road derailleurs
Thank you for the video. I have a question: do you know whether the GRX81x 0series rear derailleur is compatible with the Ultegra (I believe, 8000-series) shifters? Thank you.
So glad that you found the video helpful. If I'm not mistaking then the GRX derailleurs should be compatible with all Shimano 11 Spd road shifters. I've definitely see plenty of riders who group the Ultegra and GRX components together. The MTB components (XT/XTR derailleurs) + Road shifters are however not compatible, I believe the cable pull is different.
@@MountainRoadRide Thank you lots for the reply! ☺️🙌🏻
How big chainring i can run on grx812 gs 11/42 casset?
Excellent vid, thanks and greetings from Brazil! So, apparently, due to limitations on the total capacity of the GRX rear derraileurs it would be impossible to run a configuration such as a supercompact cranckset with 30/46 teeth and a big cassette at the rear with 11/42 teeth, right? Because that would correspond to a "capacity" of 47 whereas the maximum capacity of the GRX 810 derraileur is of 40, right?
Greetings! Yes, technically that setup should not be run. That said, Shimano will always be conservative when they state the capacity of their groupsets, just to be on the safe side. I’ve seen people run a 30/46 crankset with a 11/40 cassette using a 810 grx derailleur, but that might be pushing your luck. What you can do however is make use of a 3rd party derailleur cage arm to extend your derailleur’s reach. Garbaruk components sells a nice cage arm option. Something to look into...
Hi, my Belgian Ridley Kanzo Adventure is fitted with the GRX shift§brake levers, front Shimano GRX 11s42T, derailleur Shimano RX Ultegra, casette shimano 11s34T....how do you rate this setup?? I ride mostly on road / gravel, no spectacular offroad... Thx and grtz from Belgium.
Sounds like a great setup. The only thing to think about is the gear ratios. The 42T(front)/34T(rear) combo doesn’t give you a very easy gear for climbing. If you don’t ride a lot of hills then the setup should work fine. If you need more climbing gears then you might have to extend the gear range. Here is a helpful tool for gear ratio analysis: www.bikecalc.com/gear_ratios
I don't really get the min and max, I run my 1x mechanical grx with a 11-36 cassette when riding outdoors and an 11-25 on the turbo trainer and it handles it no problem, in fact i've had more trouble trying to run a 11-46 cassette.
Yes I guess they'll always list the specifications to be a bit more conservative. It really just comes down to how much strain you want to place on the b-screw when you adjust it for the different size cassettes.
hi, can i use a 11-46 cassete with ultegra rx8000? thanks a lot¡!
Out of the box the Ultegra Rx 8000 can’t shift through an 11-46 range. The Rx 8000 is build for an 11-34 cassette, but some riders claim that they have been able to push it to an 11-36. You can use the Wolftooth Roadlink (bit.ly/3JLjRxs) and push the range to 11-40. One way to get it to work with an 11-46 cassette is to use something like the Garbaruk cage arm (www.garbaruk.com/rear-derailleur-cage-for-shimano-grx-11-speed.html?category=15)
@@MountainRoadRide many many thanx. could be other option setup a rear derailleur XTR 11v with shift levers Ultegra RX8000? I would like to setup a "gravel bike" from my mountain bike. Thanks¡!
will ultegra rx or grx will be compatible with 11-46 cog
I think the 46 cog might be a bit out of reach for the grx derailleur’s cage. You can however use something like the Garbaruk rear derailleur cage arm to extend the range of your grx derailleur - even up to 50cog capacity.
GRX - another way to make Millennials think their getting something special when road or mountain gear works just as well
Ultegra RX is discontinued and GRX is basically r8000 with a clutch system. Mountain RD can't be used on road shifters so tell me, how can you have clutch system on poor roads and off-road without GRX?