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I purchased Kona Rova AL 650 last year. I am riding frequently and probably put a lot of wear on the bike. As a result I broke the Rear Derailleur Shimano Claris and Hanger (picture attached below).

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These two parts are in unrepairable condition. As I did not like Claris, I want to upgrade to Shimano Tiagra (and from 8 to 10 gears). Unfortunately, my local shop and their contracted suppliers have no spare parts available (I am based in the UK) and my only option is to try to source the parts myself.

I am creating list of parts I think I need (below), however, there are some technical nuances (e.g., mounting) that are beyond me:

  • [The original part needs replacement] Kona Hanger AA
  • [The original part needs replacement] Shimano Tiagra HG500 10 Speed Cassette (11-34)
  • [The original part needs replacement] RD-4700 Tiagra 10-speed rear derailleur, GS - I found the "medium" type (GS) but I have no idea if it will fit.
  • [The original part works] Shimano Tiagra Front Derailleur - There are different mounting styles and it is difficult to see which derailleur is correct. Maybe I can get away with keeping Claris on the bike?
  • [The original part works] ] e.g.: Tiagra ST-4700 Shifter - There are different types and as they are not damaged I think that maybe I can get away with leaving Claris on?

I would appreciate if others could have a look at the list and let me know if these will fit all together/my frame/if I need something else/pay special attention to.

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  • Tiagra 4700 and Claris R2000 are effectively incompatible. You obviously can’t shift a 10s drivetrain with 8s shifters. Pick one or the other entire setup.
    – MaplePanda
    Commented Oct 5, 2021 at 6:10
  • Thanks for the comment. Can you please share example of entire setup that you think would be suitable for the bike described in my question? I am asking as even when I look at the entire line (bike.shimano.com/en-EU/product/component/tiagra-4700.html) there are many choices for each component, for example, back derailleurs come in two sizes, front in four sizes, three types of drop handlebars.
    – user61027
    Commented Oct 5, 2021 at 11:02

1 Answer 1

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There is no way to make your right 8-speed Claris STI index on any 10-speed cassette. It doesn't have the clicks.

The most minimal way of doing it would be replace the right STI and the rear derailleur, say both with Tiagra 4700 parts, and then the cassette, chain, and front derailleur. Limping the bike along with an 8-speed claris FD on a 10-speed chain is a recipe for frustration even though it can be made to sort of work. I don't think that the Claris STI will play nice with a long-armed FD like FD-4700, so if you were to only replace one STI you'd be better off getting some older 10-speed road FD that would work well with the compact cranks on your bike, like an FD-4600 or FD-5700 etc.

More sensible approach for almost everyone, especially in the era of parts shortages: Get any reasonable condition long cage (SGS) 9-speed XT, SLX, or LX you can get your hands on, for example RD-M770 or RD-M760. They will have the total capacity and large cog clearance you need for your 50/34, 11-34 drivetrain, will work perfectly with your Claris shifter on 8-speed with an 8-speed chain, and be much nicer for your bike and appropriate for someone who is outgrowing entry-level components. There is no hack or contrivance to this setup because the actuation ratio is the same as what you had, and will only work better because of being a higher precision part. Then, when the time comes, if you want to ditch your Claris STIs, get any older 10-speed set, but not ST-4700, 10-speed GRX, or any newer ones that are out then, because they use the newer different generation of 10-speed cable pull. If you got something like ST-6700, 5700, or 4600, they will all work perfectly with the higher-end 9-speed RD you buy now to shift 10-speed. Note that ST-5700 and RD-M770 are still made as legacy components (and when/if they go something else will likely take their place), so you're not necessarily locked in to buying used things.

The drawbacks with this plan are you don't get a clutch and you're using some older things, but it would be a way of incrementally upgrading the bike that would work and not be weird. If what you really want to do is take it to a whole other level and have the modern niceties, I think it's better to buy new STIs, RD, FD, chain, and casette all at once, and at that point you possibly may as well go 11-speed, depending on what you come up with for cost and availability. There's of course another piece to the whole question of if you were going to upgrade the components in one of the plans that requires switching the STIs, do you really want to stay with mechanical brakes.

Also note that when rear derailleurs bite it as shown in the picture, it's fairly uncommon for the chain to survive intact. Unless after looking through it you're very confident there are no twisted or mangled links, you should replace it along with the other parts.

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  • Old post, but for the sake of posterity: "The most minimal way of doing it would be replace the right STI and the rear derailleur" -- I was told that Shimano's 8, 9, and 10 speed (excluding 4700) would have compatible rear derailleurs as far as cable pull goes. Perhaps finding something like a 5700 shifter would be easier and/or cheaper than finding both a 4700 shifter and a compatible derailleur (4700 or perhaps the more expensive 11-spd parts)?
    – jayded-bee
    Commented Oct 25, 2022 at 10:52
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    @jayded-bee No, you can't just use fewer of the clicks. The total cable pull of an ST-5700 would be the same, but the pull per click is less than needed because it's divided by 10, not 8. Commented Oct 25, 2022 at 15:02
  • If the total cable pulled (from the smallest to largest cog) is the same between rear derailleurs, surely it is only the shifter that must be adapted to however many speeds you want to use? As I understand it, OP could have taken a 10-spd (excluding 4700) RD and mate it to any shifter?
    – jayded-bee
    Commented Oct 26, 2022 at 16:05
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    @jayded-bee I may have misunderstood. Yes, if we're talking about cheapest ways of switching this bike to a 10-speed rear end, if one happened to have access to something like a 5700 shifter and appropriate derailleur for cheaper (which then would likely be a 9-speed mountain one to handle the 11-34), that is a way to go. But it wouldn't be a pre-4700 Shimano road 10 RD you'd do that with, because none of them can handle 34t reliably. Commented Oct 26, 2022 at 17:22
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    It also bears mentioning that while for a while 4700 was the only "new pull 10 speed" group, 10-speed GRX now uses the same pull and it appears likely that all future 10-speed groups will as well. Commented Oct 26, 2022 at 17:27

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