Which Groupset?

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  • I've never seen one so have no idea. I'd expect stuff designed for off-road to be as 'hidden' as possible.

  • https://www.reddit.com/r/gravelcycling/c­omments/e6luiw/ultegra_rx_vs_grx_rear_de­raileur_what_gives/



    Shimano GRX RD-RX815 Di2 rear derailleur is a combination of the Shimano Ultegra RX rear derailleur and a Shimano mountain bike rear derailleur. It features a slim Shadow profile and clutch mechanism but has a slightly stronger clutch compared to Ultegra RX. It is also very slightly heavier than Ultegra RX, but the overall quality matches that of Shimano Ultegra. The Shimano GRX RD-RX812 rear derailleur is 1x-specific


  • Thanks, i saw the diff capacities on the two GRX derailleurs; I'm not looking to drop the front mech so I think the 812 doesn't officially work...

    Tempted to try the 810 because what's the worst that can happen Vs buying a normal ultegra?

    That said I should probably make sure I have a frame to put it on first, hopefully the mason is still useable despite its troubles

  • Happened multiple times and you checked FD setup in between


    all I can think of is an issue with the BB (but you didn't swap that?) or the rings themselves

    The two Di2 bikes had different BBs - Rotor BSA30 on one, FSA on the other. The rings have behaved perfectly since I fitted them to the Cannondale with the mechanical DA9000 groupset - never a problem.

    is it possible to install them backwards or something? I can't remember. I think there's plenty of writing on them telling you which way to install them so unless you were drunk every time you checked? :)

    There's a fighting chance I was pissed as a fart every time I installed them, but even drunk as a newt I wouldn't fit them the wrong way round - the recesses for the chainring bolt holes would be on the wrong side of the chainring.

    Maybe you got unlucky?

    That's my conclusion - I'm just cursed. From now on, no Brommers+Praxis+Di2 combinations.

    I'll take them off you. :)

    You're too kind, but happily I still have enough bikes with mechanical shifters that I can find a home for them.

  • the next Q is whether the GRX would be more resistant to knocks!

    On the basis that I've written off two Shadow Shimano MTB RDs in crashes, I'd say any benefits will be marginal. If you crash, and lay down the bike on the ground on the drive side while still moving, I doubt any additional clearance will be much use. If you don't crash, your legs will take the impact first, and provide a useful crumple zone for the rear derailleur.

    My advice - don't crash. As usual, I am very bad at taking my own advice...

  • The new rings on my new Zayante's are right good.

    TBF Praxis shift great on pair with Shimano, it’s the cost of the ring and wearing out quickly the main issues.

  • So, the issue appeared on both BBs? They were the same size rings but did you change the height of the FD at any time? What size gap did it have over the big ring teeth?

    Given it works with mechanical fine, is there actually a measurable difference between cable and Di2 FD cages? If they are the same dimensions then it must've been something specific to the first install. If the FD dimensions are different then maybe there's a reason in that.

    Did you have the little offset middle bolt adjusted properly? I know this is sucking eggs theory but the Di2 limit screws work a bit differently to cable limits stops.

    I want to take my 10spd cable back to Oz where I don't need to change gears. The cables will last forever and I'll no longer need to buy 10spd parts.

  • My aftermarket Praxis rings seem totes durable and you'd be hard pressed to be doing more miles on them than I did in the last few years.

  • Good advice. I'll try...

    I guess that gets me back to my original question and the answer seems to be there's not much in it to choose the grx over the normal mech

  • Just for hippy because he loves the corkscrew company so much
    New campag freehub - getting ready for the 1x group with 10t cassette sprocket

  • I admire their stance on backward compatibility. If only someone still owned their hubs... ;)

  • Chris King for example has discontinued Campag freehubs for their R45 hubs.

  • Anyone looking for 10 speed groupset?

    (Sorry I know it’s spam)


  • When the fuck did Shimano FDs get so fucking difficult to adjust? What's with all the weird linkages and shit on the R8000? Fuck me. I've clearly led a sheltered life going from 7800 to Di2.

    I just spent an hour working on a neighbours bike and still the fucking thing was piss. There must be a magic starting position that changes properly and doesn't hit the cranks or the rings. I didn't find it.

  • the cable is not supposed to exit, but be tucked in

  • get campag

  • The beauty of 8000 and 9100 is never having to adjust the FD once set up properly. And you take the slack out of the cable

  • Yeah, I worked that bit out after 20 fucking tries to get everything working and once it was tucked in the arse end of the cage was hitting the crank arm and I gave up and had dinner.
    7800, it's like up/down, align with big ring, tighten off cable, fucking sorted. Why'd they add another linkage with the bumper stopper thing and OMG I didn't see the fucking barrel adjuster coz it's an aero frame argh fucksake, gimme an old Tarmac any day.

  • You say that but this is someone's bike who's FD was working and then wasn't working. I can only assume something was loose from the shop and it loosened off further during a ride.
    I thought I had it and then trying to take the tiiiiiny rub out of it and argh fuck it's too far out again.

  • Did you not round out the cheese allen head bolts as well.

  • oh yeah i forgot, the tiny allen screw is the barrel adjuster

  • Yep. Fiddly to set up at first, but ideal for bikes that don't have barrel adjusters and can't have them fitted. Here's looking at you, Cervelo RS Team.

  • all things considered, a pretty good design, cable ferrule and adjuster all in one neat place. all it takes is to read the manual, which is beyond the reach of most of us

  • No, looked like the owner had tried to though.

  • Had another go at the R8000 FD and it's better but still not perfect. Rubs inside the cage at the extremities. Turns out you need to start with it piss, not straight and once it's bolted to the braze on, then you use that stopper screw to push the arse end straight. It still barely clears the crank arm when it's clearing the chain though. Next thing to try is that cable tension screw. It didn't even look like an allen key hole on this FD, it looked like a pin but watching a vid it turns out that little bastard should be right out when you pull the cable through and then you can get the cable tighter with the 2mm cable tensioner. Not sure how much difference that will make to the actual cage position, but maybe it means it will move slightly further out with a lever throw so I can back off the H limit and then it won't be so close to the crank arm, but then again that doesn't make sense to me because the cage should be parallel anyway so it doesn't matter if the cable moves it or the limit screw moves it, right? Only one way to find out..

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Which Groupset?

Posted by Avatar for braker @braker