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Shimano 105 5700 rear shifter - lack of precision

lukasamdlukasamd Posts: 50
edited October 2017 in Workshop
Hello,
I have CX bike (Planet X XLS from 2014) with Shimano 105 5700 shifters and RD-5701 rear derailleur.
Used with Ultegra 6701 chain, Ultegra 6700 11-28 cassete and FSA Gossamer 46/36 cranset.

And.. I have problem with rear derailleur precision - exchanged cables twice, clean all, but it still doesn't work like should work - older ultegra 6600 shifters/derailleur from road bike were much, much better. Sometimes must pull higher gear and then go down or vice versa.. it's frustrating.

I read about similar issues in 5700 and 6700 groups and don't know what should do - try other cables (maybe Shimano PTFE?) or prepare to upgrade to 11s? Unfortunately it's high cost.

Posts

  • davesnotheredavesnothere Posts: 1,838
    Try swapping the mech hanger? If it's slightly bent might be throwing it out
    GET WHEEZY - WALNUT LUNG RACING TEAM™
  • No, I've just replaced hanger after small accident :)
    New is fine.
  • slowbikeslowbike Posts: 8,476
    I've got a problem with the bottom bracket cable guide - the cable has dug a groove into it causing it to stick on changing down.
  • I have internal cable routing, but it was also checked - everything looks good, clean etc.
  • slowbikeslowbike Posts: 8,476
    lukasamd wrote:
    I have internal cable routing, but it was also checked - everything looks good, clean etc.

    ok - internal cable routing is harder to diagnose because you can't actively get at the cable ... I found mine was a distinct difference in cable tension from the downtube to the stay - threaded a bit of outer and placed under the bottom bracket and shifting improved (now needs replacing and doing properly)

    Assuming you've got this on a stand or can put it on a turbo - remove the shifter and connect it directly to the rear mech with a short bit of outer & inner - test the shifting - if that's all fine (you may need to test with a second person using a turbo to test under load) then it's all to do with cable tension & friction ... if it isn't then it's either your shifter or your mech - could be the spring in the mech isn't strong enough to pull the cable? At which point I'd look at testing it with a different mech.
  • bobonesbobones Posts: 1,018
    There's nothing intrinsically wrong with 5700 other than its tendency to fray cables in the RH shifter so you shouldn't need to upgrade to 11 speed. I would double check that the hanger is sufficiently tightened to the frame dropout and aligned correctly (you did realign when you replaced the hanger?), test the shifting with externally routed cables to rule out snagging inside the frame. If the RD cage and spring feels sloppy then consider replacing the RD itself.
  • davidofdavidof Posts: 2,018
    11x28 is quite a big range, have you adjusted the B screw.
    That said I run my 5800 on a 13x32 and have similar problems which I've never fully sorted.
  • all 10 speed road groupsets (except tiagra 4700) lack of precision SERIOUSLY!! That is the main reason they changed the cable pull and shift ratio on 11sp and 10sp tiagra 4700. I had both ultegra 10sp and 105 10sp and for a week a set of dura ace 10sp. they all lack of precision. they pull litle for litle so everything in the cables has to be perfect. sell the 5700 shifters and deraileur and get yourself a tiagra 4700 series. you will be amazed with the precision you will find there. plus, the tiagra rd-4700 medium cage can go up to 34t large cog just for fun!
  • svettysvetty Posts: 1,904
    Likely pivots in the mech are a bit gunged up - you can't always assess this properly without stripping it down, cleaning it properly, putting fresh grease in and re-assembling.
    FFS! Harden up and grow a pair :D
  • davidofdavidof Posts: 2,018
    tsarouxaz wrote:
    all 10 speed road groupsets (except tiagra 4700) lack of precision SERIOUSLY!! That is the main reason they changed the cable pull and shift ratio on 11sp and 10sp tiagra 4700.

    I went and checked what you said and you are spot on. It seems the best upgrade from a 10sp system is to get a Tiagra rear mech and shifter. People are running 36T no problem, great if you have some extreme climbing (some places I ride would be great with those ratios: 20-25% over 2km).
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