Are GRX Di2 shifters worth extra $400 over R785/6870 Di2?

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disq
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Location: Richmond UK
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by disq

If we're weighing shifters ourselves, we need to take into account if there's any mineral oil in the chamber or not... A brand new GRX shifter set comes pre-filled with mineral oil (you literally pull the yellow plugs, shorten and connect the also filled hoses and go... no bleeding necessary) so I'm guessing the weight would differ between a completely empty shifter versus a filled one.

szazbo
Posts: 114
Joined: Mon Sep 18, 2006 6:26 am

by szazbo

disq wrote:
Wed Apr 28, 2021 8:51 pm
If we're weighing shifters ourselves, we need to take into account if there's any mineral oil in the chamber or not... A brand new GRX shifter set comes pre-filled with mineral oil (you literally pull the yellow plugs, shorten and connect the also filled hoses and go... no bleeding necessary) so I'm guessing the weight would differ between a completely empty shifter versus a filled one.
Well in theory you can just plug and play, but I have always found air in the system and required bleeding to get a firm feeling lever. I would also predict that you could not weigh the minimal amount of mineral oil that the entire system holds

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disq
Posts: 38
Joined: Tue Apr 13, 2021 9:22 pm
Location: Richmond UK
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by disq

szazbo wrote:
Wed Apr 28, 2021 9:56 pm
disq wrote:
Wed Apr 28, 2021 8:51 pm
If we're weighing shifters ourselves, we need to take into account if there's any mineral oil in the chamber or not... A brand new GRX shifter set comes pre-filled with mineral oil (you literally pull the yellow plugs, shorten and connect the also filled hoses and go... no bleeding necessary) so I'm guessing the weight would differ between a completely empty shifter versus a filled one.
Well in theory you can just plug and play, but I have always found air in the system and required bleeding to get a firm feeling lever. I would also predict that you could not weigh the minimal amount of mineral oil that the entire system holds
I was able to plug and play and the lever is firm, of course making sure not to spill any oil once I shortened the hose etc. The hoses came connected to the callipers and they were pre-filled with a cap on, just like the levers. In fact I can't get the lever to be this firm in my mechanical Ultegra (R8020) bike.

OnTheRivet
Posts: 732
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by OnTheRivet

disq wrote:
Wed Apr 28, 2021 8:51 pm
If we're weighing shifters ourselves, we need to take into account if there's any mineral oil in the chamber or not... A brand new GRX shifter set comes pre-filled with mineral oil (you literally pull the yellow plugs, shorten and connect the also filled hoses and go... no bleeding necessary) so I'm guessing the weight would differ between a completely empty shifter versus a filled one.
You need to bleed them. You always need to bleed them.

disq
Posts: 38
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by disq

OnTheRivet wrote:
Thu Apr 29, 2021 6:55 pm
disq wrote:
Wed Apr 28, 2021 8:51 pm
Do this
You need to bleed them. You always need to bleed them.
RX815 Manual page 96 says:

7. Remove lever stopper
8. Check pad etc
9. Operate the brake lever several times and check that the brake pads grip the disc brake rotor and that the lever becomes stiff.
If the lever does not become stiff, refer to “Adding mineral oil and bleeding air” and bleed the air from the system.

The levers I had went stiff on the first try (both front and rear), so didn't need to add oil/bleed. Granted I was very careful with the hoses and the positioning of the levers (hydro port "looking up" during insertion) and didn't spill any. About 500kms in so far, steep descents and everything, no issues.
So that's possible.

Js2
Posts: 194
Joined: Mon May 08, 2017 6:55 pm

by Js2

I find GRX Di2 levers really good for Off-road, definitely worth it if its in your budget despite being heavier than its Ultegra Di2 Hydro counterparts.

The brake feel and ergonomic is superb to me when things get rough. Out on the road i prefer the smaller shifters hoods. I believe te GRX Di2 Shifters have a longer reach too on the top part compared to the Ultegra/Dura Ace variant.

tjvirden
Posts: 540
Joined: Sun Nov 22, 2020 9:21 pm

by tjvirden

I'm using the GRX Di2 levers on a bike that sees 85/15 tarmac/"gravel".
I find them superb whenever I'm out of the saddle and I'd describe them as different to R8070/R9170 otherwise. The aero hoods position requires that you change how you position your fingers and the angle of the wrist, but in some ways the shifting actually becomes even easier because of that. It'll come down to personal preference.
R8070 levers are about 12g less per side.

Edit: The GRX Di2 extra buttons are fine without gloves, but I think the Ultegra/Dura Ace extra button is better overall.

LanceLegstrong
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Joined: Fri Sep 13, 2019 1:35 pm

by LanceLegstrong

tjvirden wrote:
Fri May 28, 2021 3:19 pm
I'm using the GRX Di2 levers on a bike that sees 85/15 tarmac/"gravel".
I find them superb whenever I'm out of the saddle and I'd describe them as different to R8070/R9170 otherwise. The aero hoods position requires that you change how you position your fingers and the angle of the wrist, but in some ways the shifting actually becomes even easier because of that. It'll come down to personal preference.
R8070 levers are about 12g less per side.

Edit: The GRX Di2 extra buttons are fine without gloves, but I think the Ultegra/Dura Ace extra button is better overall.
I went from the 785 to the GRX Di2 on my CX bike and they're amazing. So much more control and braking power from the hoods. But I totally agree the Ultegra/Dura-Ace top button is so much better than the GRX button. I hate the GRX side button. Only flaw from my view.
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kroem
Posts: 435
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by kroem

I like GRX so much I went with them for my road build.
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Current
Waltly Gravel (stolen... and found!)
P-X Spitfire Ti
Fairlight Strael

Old
Canyon Ultimate SLX 6.7kg (crashed)
Tantan GR039 7.2kg (sold)

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