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Shimano left shifter won't shift up to big ring

I bought some Shimano Ultegra (ST-R8020) double hydraulic shifters in May last year. After a couple of months, I noticed an intermittent problem, when I wanted to move up to the big ring the lever wouldn't move, it felt like I'd break it if I pushed too hard. After riding a few hundred metres, it would suddenly allow me to shift up. This carried on with increased frequency until I can no longer move into the big ring.

I've changed the inner cables twice and the outers once, moved the front mech by hand to check it moves freely, checked the chain doesn't foul the chainrings, flushed the shifters out with a silicone lubricant but nothing makes a difference. If I disconnect the cable and hold the cable while moving the shifter, it appears to work so it's only when it's under load that it won't shift.

I've setup loads of front mechs on all my bikes and never had an issue like this. Has anyone had a similar problem?


  • webboowebboo Posts: 6,078
    Is it compatible with your front mech.
  • rafletcherrafletcher Posts: 1,235
    Sound like the shifter is broken. It happens. Not sure if they're rebuildable. But if they were bought new they'll still be under warranty.
  • hdowhdow Posts: 183
    Yep, had exactly the same problem with the left shifter and was unrepairable. With mine the spring driven widget that should click into the ratchet that pulls/releases the cable broke it's spring. As rafletcher says they are still under warranty (should be 2 years) so get a claim in ideally via your retailer. Worked for me. Then the right shifter did exactly the same.
    The claim may take a couple of weeks and there have been supply issues with the R8020s, both left and right. You don't say where you bought them but your local LBS may run the claim and the claim should include the cost of fitting.
  • skeetamskeetam Posts: 178
    edited January 2021
    webboo said:

    Is it compatible with your front mech.

    Yeah, both are Ultegra r80XX and 2x.

    I bought them new from and I emailed them to ask if they could help. They sent me a prepaid label and said the claim with Shimano will take at least 5 weeks. That's a long time to stay in the big ring πŸ˜‚

    Might have to buy a cheaper (105) one from somewhere and fit that 😞
  • MattFalleMattFalle Posts: 11,644
    8000 breaks all the time - mine did after 300 miles, shop said it was well known - Madison ran out for a while due to so many being returned for warranty.

    Sounds like ypurs has gone unfortunately, so warranty replacement.
    The camera down the willy isn't anything like as bad as it sounds.
  • ibr17xviiibr17xvii Posts: 1,065
    My R8000 did much the same after less than 2000 miles.

    One minute it was working the next it wasn't.

    My new one still does it now intermittently.
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