Shimano GRX ?
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Thread: Shimano GRX ?

  1. #1
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    Shimano GRX ?

    I was looking at some Jamis bikes on their website, since my LBS is now a Jamis dealership. Several of their road bikes were equipped with Shimano GRX components. I had never heard of it, and from what I could decipher, the GRX signifies "gravel". I didn't see any of the usual DuraAce/Ultegra/105 stuff.

    Anyone familiar with the GRX components? Any good?
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    The main difference is you can get cranksets that are 46/30T and 48/31T. The chainline is about 3mm more outboard, to give a bit more clearance. The brake levers are claimed to be an ergonomic improvement over Ultegra, for those who ride the hoods a lot, and brake from that position. The 46/30T crankset is supposed to be approximately 105-level, and the 48/31T is at Ultegra level. I have the 46/30T crankset and the quality is indistinguishable (to me) to that of my 50/34T Ultegra crankset, so I think these designations are a bit arbitrary.

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    Do you ever spin out on the road with the 46?

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    GRX is basically the 105/Ultegra/Dura-Ace of the gravel parts. There's 800, 600, and 400 level parts respectively. I've only played with the GRX800 mechanical stuff, but it does make me drool a bit with me mish-mash of Di2 parts. The levers alone are a nice change from say R685/785.
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    It's brand spankin' new as of last year. It's really good stuff.

    While it's definitely geared towards 'gravel', it's got some great components and they are all interchangeable/compatible with other Shimano 11 speed components and there is no reason not to run it on the road. It lends itself to a wider range of gearing and larger rear cassettes, which is good for casual cyclists and folks that live in really hilly areas.

    One caveat is, you really need to keep the GRX Front Derailleur and Crankset together, as the chainline is about 2mm further outboard (to support better clearance for wider rear tires) than on the DA/Ultegra/105 components. You can probably get away with running them individually with other components, but it's best to avoid it if at all possible.

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    Quote Originally Posted by rideit View Post
    Do you ever spin out on the road with the 46?
    No, but I am slower than many people here. Compared to 50 front 11 rear, you only lose the highest gear. A 50 - 12 is about the same as a 46 - 11.

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    Quote Originally Posted by Marc View Post
    GRX is basically the 105/Ultegra/Dura-Ace of the gravel parts. There's 800, 600, and 400 level parts respectively. I've only played with the GRX800 mechanical stuff, but it does make me drool a bit with me mish-mash of Di2 parts. The levers alone are a nice change from say R685/785.
    More like Tiagra/105/Ultegra of gravel.


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    The 10 speed 400 series is pretty much Tiagra for gravel.

    The 11 speed 600 series parts are 105 level. The shifters use regular cables and the cranks are solid alloy with 46/30 rings or a 40T single.

    With the 800 series parts you get Ultegra level specs. Cables are polymer coated and the cranks have hollow arms as well as the 48/31 rings or a choice of 40T or 42T single. Rear mech is essentially the replacement for the earlier stopgap Ultegra RX800 & 805 clutched mechs. Di2 parts follow the same line as Ultegra in level.

    All of the shifters have a higher pivot point for the brake lever to assist with better control, as well as a more hooked hood to improve grip on rougher surfaces.

    Brakes are all flat mount hydraulic with the same hoses as R-Series road brakes. The 400 & 600 series share the same RX400 caliper, with the 800 series getting its own lighter caliper.

    Overall, if you're comparing the GRX offerings to their Tiagra/105/Ultegra cousins, GRX is a little heavier by virtue of its intended use. The chainsets have been optimised to accommodate wider tyres generally encountered on gravel & allroad bikes. The gearing is a little lower, again due to its intended use.



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    The other thing I would add is the 800 series gets the servo wave technology in the brakes at the shifters (the calipers are identical to Ultegra) which takes up the free travel quicker than Ultegra.

    Also the Di2 hidden buttons are moved to the inside of the shifter instead of the top of them which is so much nicer. Personally I find the top location for these can be a bit frustating having to fish around to find the right place to press to actuate them, which is not the case for the GRX Di2. I'd be the next generation of Di2 and Ultegra will move these buttons to the inside as well.

    The other thing perhaps noteworthy for GRX Di2 shifters is they have 1 accessory port for remote shifters like the Ultegra and Dura Ace Hydraulic brake shifters, not 2 ports like the mechanical brake shifters from those groupsets.

    The rear DRs get a clutch adjustable tension to keep the chain tension when freewheeling on rough pavement to prevent chain drops and chainstay slap
    Last edited by Srode; 03-05-2020 at 04:22 AM.
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    With mechanical GRX you can also run 1X drivetrain and use the front shifter for a dropper post.

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    My big question is did Shimano sort out the cable-eating problem with these shifters?
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    Quote Originally Posted by Lombard View Post
    My big question is did Shimano sort out the cable-eating problem with these shifters?
    What cable-eating issue? As far as I can recall that was 9000 series Dura Ace.


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    I wonder how long it will be before Shimano or Pro release a Di2 actuated dropper post.


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    Quote Originally Posted by ultimobici View Post
    What cable-eating issue? As far as I can recall that was 9000 series Dura Ace.
    The cable eating problem was on both generation 5700/6700/7900 and 5800/6800/9000. I believe it still exists on 7000/8000/9100.
    "If someone needs 200 rolls of toilet paper for a 14-day quarantine, they probably should have made a doctor's appointment way before the COVID-19 outbreak." -- Unknown

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    Quote Originally Posted by Lombard View Post
    The cable eating problem was on both generation 5700/6700/7900 and 5800/6800/9000. I believe it still exists on 7000/8000/9100.
    I don't run mechanical drive trains any more, but I've run pretty much all of these in the mechanical form at some point in the past, and I honestly never had any issues with cables fraying/breaking in the lever/hoods.

    Is it really that prevalent?

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    Quote Originally Posted by Finx View Post
    I don't run mechanical drive trains any more, but I've run pretty much all of these in the mechanical form at some point in the past, and I honestly never had any issues with cables fraying/breaking in the lever/hoods.

    Is it really that prevalent?
    It is.

    Some people just can't accept that a $5 part will wear out and need to be replaced. No one questions brake pads, tires and chains but because other companies make them last longer cables seems to be really hard for people to accept they need to replace them.

  17. #17
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    Quote Originally Posted by Jay Strongbow View Post
    It is.

    Some people just can't accept that a $5 part will wear out and need to be replaced. No one questions brake pads, tires and chains but because other companies make them last longer cables seems to be really hard for people to accept they need to replace them.

    Thing with cable chewing...it isn't just a "you need to maintain your bike" problem. Last year on a gravel grinder ride, guy was on a new Salsa with R8000 Ultegra. 1 month old bike. He went from having a 22-speed bike to a 2 speed bike in the first 11 miles. And of course once the cable is chewed inside the shifter and breaks good luck getting it out.

    I don't know whether Campagnolo has magic shifters--because I've never heard of rampant cable chewing on 10/11/12s Campagnolo....of if there are that many Shimano parts on the margins oif passing QC or what.
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    Quote Originally Posted by Marc View Post
    Thing with cable chewing...it isn't just a "you need to maintain your bike" problem. Last year on a gravel grinder ride, guy was on a new Salsa with R8000 Ultegra. 1 month old bike. He went from having a 22-speed bike to a 2 speed bike in the first 11 miles. And of course once the cable is chewed inside the shifter and breaks good luck getting it out.

    I don't know whether Campagnolo has magic shifters--because I've never heard of rampant cable chewing on 10/11/12s Campagnolo....of if there are that many Shimano parts on the margins oif passing QC or what.
    yeah that's a different story. One month might be a defective shifter or cable, unless he's doing some real serious miles or insane amount of shifting.

  19. #19
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    Quote Originally Posted by Jay Strongbow View Post
    yeah that's a different story. One month might be a defective shifter or cable, unless he's doing some real serious miles or insane amount of shifting.
    I really don't consider 1500-2000 miles as "reasonable wear and tear".
    "If someone needs 200 rolls of toilet paper for a 14-day quarantine, they probably should have made a doctor's appointment way before the COVID-19 outbreak." -- Unknown

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    -- DCGriz, RBR.




  20. #20
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    Quote Originally Posted by Lombard View Post
    I really don't consider 1500-2000 miles as "reasonable wear and tear".
    If you use Shimano Cable lube they will last longer. But even without the lube, I never had one break in less than 3000 miles when I had cable shifting, normally with the lube I was changing at around 8000 miles.
    Gravel Rocks

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    Niner RLT9 (Gravel Bike)
    Niner RLT9 RDO
    BH G7 Disc
    Trek Crockett

    "The Spirit of the Party "serves always to distract the public councils and enfeeble the public administration. It agitates the community with ill-founded jealousies and false alarms, kindles the animosity of one part against another, foments occasionally riot and insurrection

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