GRX vs Ultegra?

I’m getting ready to buy or build a new gravel bike. I’ve used old Ultegra 10 speed and current Tiagra 10 speed on cyclocross and gravel bikes and have been satisfied with the performance. I’m trying to decide if I should grab one of several 2019 bikes built with ultegra that are now on close out or hold out for a GRX800 build.

As best I can tell the key differences with GRX compared to Ultegra gravel builds:

- GRX shifters have a different shape, textured hoods, and different pivot for better leverage when braking
- GRX cranksets can run smaller than 34t chainrings
- GRX rear dereailluers have different capacity (but both Ultegra RX and GRX have clutch mechanism)

Any other differences that might push me toward GRX?

Hey,
Had similar problem before. I also was between ultegra and grx. I could get over the look of grx levers,, so sent for ultegra levers and grx rear derailleur with 11-42 cassette. Works good. So only thing is - does your riding benefit from that braking pivot thing 

GRX front derailleurs have a 46mm chain line and therefore require a matching crankset with 2.5mm offset that will increase your Q factor with 2x3mm. This enables frame builders to flare out the chain stays in order to support wider tires. A bit like boost did for MTB frames. I’m however not sure there are any existing gravel frames on sale right now that need this additional offset.

If your frame allows it (99.9% chance) you can of course always decide to use a regular 2x compact 46/30 crankset with an Ultegra front derailleur in combination with GRX shifters and GRX rear derailleur, both for mechanical and Di2 shifting.

The 817/812 rear derailleurs support up to 42T where Ultegra maxes out at 34T similar to the 815/810. If you want a 1x set up then going for the 817 GRX is highly recommended.

A lot comes down to how much you want to spend. Ultegra shifters and derailleurs with another brand of 46/30 crank will be cheaper and you don't sacrifice compatibility with other brands of drivetrain parts. The 8000 series Ultegra shifters have a much better shape than the horrid RS785 levers. One thing I've never found with any disc brake is the need for more leverage, so I question whether there's any real value to that GRX change.

I just ordered an RX805 rear derailleur for my existing gravel rig. I have no intention of ever going 1x, so it has more than enough capacity for my needs and I'm looking forward to the real benefits of the clutch.

bnystrom wrote:...the horrid RS785 levers.

Why are they terrible? I was under the impression these are closest to the GRX shifters in shape with the raised hoods and all. I’m actually planning to use them in my GRX Di2 build as I have them laying around and I was looking forward to their modulating breaking capacity...

Haha ok thanks for the honest reply, at least I won’t be surprised when they indeed suck as much as you indicate.

I'm happy to steer people away from this junk. If the 8000-Series Di2 and GRX levers weren't so expensive, I'd upgrade to them. For now, I'll suffer with what I have and gripe about them.

Another question: Is it possible to upgrade groups like TIAGRA, 105, ULTEGRA by adding some GRX parts? Is there compatibility between them? 

Gabriel wrote:
Hello. I'm new here. Sorry for my bad English. Are the RS785 STI´s the SHIMANO 105?

No, they're Di2/disc brake levers that were/are typically sold with Ultegra derailleurs.

bnystrom wrote:
No, they're Di2/disc brake levers that were/are typically sold with Ultegra derailleurs.

Thanks for the clarification.

So from tiagra 4700, which is 10 speed, you can add grx and other 11 speed road stuff and it will be compatible. 4700 has same cable pull as 105/ultegra/grx ,just that it has 1 gear less. Grx cranks have different chainline, so you will need also grx front der. , If you want to run 2x at the front.

They also sell these together with Di2 Alfine 11s hubs for touring bikes.

As long as you’re not mixing 10s & 11s and road & offroad you can pretty much mix up all three group sets you mention with GRX.

Friends, but in short? Is GRX much better than ULTEGRA and other ROAD groups currently used at Gravel's? Like I said, the Shimano 105 group is VERY good !! I don't realize the need for something better for amateur cyclists like most of us.

GRX 800 is on par with Ultegra regarding material usage and weight, 600 with 105 and 400 with Tiagra. Main advantage of GRX over the road group sets is better grip on the shifterhoods and the clutch on the rear derailleur that will control the chain a lot better on bumpy trails. This clutch was introduced with Ultegra RX 1-2y ago but I think that’s now phased out since the introduction of GRX.

Thijsvanderwal wrote:
Why are they terrible?

They aren't. It's okay to have preferences on the shape, but I'm in the camp of them being my favorite shape ever. I have big hands and those levers are my absolute favorite. It's a shame you need to have a few Y wires if you want to use the bar end junction box, but otherwise I have no problem with them.

I don't understand the upset with the hoods either. I replaced mine this year after a full 3 seasons just because they were getting worn. They weren't stretched on my ride. I always spray rubbing alcohol in the hoods and on the lever before sliding the hoods (effortlessly) into place. They dry on their own. It's the best way I have found to install hoods on any road levers.

The gripes with bleeding is odd too. There's one single bolt holding the cover on. Then there's the single bolt for the reservoir that you take out to put your cup in. Shouldn't be difficult for somebody with 45 years of experience. I can't imagine the newest versions (which I haven't worked on) have any less fasteners to do a bleed.

Everything works as it should. They are a great shape for my hands. Maybe they won't be for yours. I get that they are pretty polarizing after years and years of mechanical hoods that weren't very big. My mechanical levers have felt too small ever since getting two hydro bikes.

Thanks dangle, it seems hood preference is as personal as other bike touch points like saddles & shoes. I’m coming from Dura Ace 7900 shifters and the 785’s don’t seem to be a lot bigger while have better texture on the hood and being higher and steeper will surely help with steep bumpy declines.

The 685s and 785s are definitely bigger than the 7900. The shape of the newest Ultegra DI2 hydro levers is really nice too (in a more tapered towards the front way). The price difference for those 8070s is just too much when you can find 785s with calipers under $250 without too much searching.

dangle wrote:
They aren't. It's okay to have preferences on the shape, but I'm in the camp of them being my favorite shape ever. I have big hands and those levers are my absolute favorite. It's a shame you need to have a few Y wires if you want to use the bar end junction box, but otherwise I have no problem with them.

I also have fairly large hands and I hate the shape, so I guess we'll have to agree to disagree on that. I've got Campy on my road bikes and I find that even their older 10 speed levers are vastly superior in comfort to anything Shimano has made, with the possible exception of GRX, which I haven't wrapped my mitts around yet.

I don't understand the upset with the hoods either. I replaced mine this year after a full 3 seasons just because they were getting worn. They weren't stretched on my ride. I always spray rubbing alcohol in the hoods and on the lever before sliding the hoods (effortlessly) into place. They dry on their own. It's the best way I have found to install hoods on any road levers.

Sliding the hoods on and off the levers is not the issue. It's getting the stupid rubber pegs in their holes and getting them to stay there. Mine pop out constantly and the hoods are also loose where they fit over the top of the levers. The base of the hoods where they meet the bars needs to be significantly larger, like most other levers on the market, including newer Shimano designs. There's a reason that these levers were quickly replaced by Shimano and you can find them on sale cheap everywhere.

The gripes with bleeding is odd too. There's one single bolt holding the cover on. Then there's the single bolt for the reservoir that you take out to put your cup in. Shouldn't be difficult for somebody with 45 years of experience. I can't imagine the newest versions (which I haven't worked on) have any less fasteners to do a bleed.

The bleeding process itself is no big deal; it's no more difficult than any other bleeding procedure I've done and the cup system is a nice idea. The issue is the tiny, easy to lose screws, but honestly, it's just an annoyance that wouldn't be an issue if the levers didn't have other aggravating problems.

Everything works as it should.

Really? Have you tried adjusting the engagement point? It's worthless. I've had Shimano Techs at a 'cross event work on them and even they admitted that they couldn't do anything with them. They bled them multiple times and there was no difference.

They are a great shape for my hands. Maybe they won't be for yours.

I agree that there's always going to be personal preferences. If the RS785s work for you, that's great. I'll gladly sell you mine!

I get that they are pretty polarizing after years and years of mechanical hoods that weren't very big. My mechanical levers have felt too small ever since getting two hydro bikes.

I'm curious, what other brands of levers have you used? Both Sram and Campy have larger, more comfortable levers/hoods and have for quite some time. Come to think of it, even the 10-speed Dura-Ace levers that came on my first 'cross bike were a better shape. They're on my girlfriend's road bike now and she likes them, but she has tiny hands.

I know that this next statement is bound to infuriate the Shimano faithful, but I would never use mechanical Shimano on an off-road bike. On the aforementioned 'cross bike, while descending a muddy hill on a wet day, the brake levers pivoted inward (as when shifting) and slipped out of my hands. I was able to re-grab them and was none the worse for wear, but there was no way I was going to risk that happening again and replaced the drivetrain with Campy. The only reason I have Shimano on my gravel bike - other that that it came with it and I bought it at a deep discount - is that the Di2 levers don't pivot to shift, so the potential problem is eliminated.