shimano gears - shoot?

[bonj2]

rapid rise rear mech not been shifting properly for a bit, then on a rocky descent at the bottom i find the top jockey wheel has fallen off. Thought the two could be related. So get a new one.

Still not shifting right. Set it up completely correctly, including setting the b-tension screw (have to back it right off as i run a 12-28), setting limit screws, then setting cable tension. But when the cable is taut enough to switch from 1 to 2, it's not slack enough to switch from 9 to 8. Slack enough to switch from 9 to 8, and it needs two index positions to switch from 1 to 2.

So put a sram one on and new sram shifter, shifts absolutely perfectly first time without even any cable tension adjustment. Shifts into each gear promptly when the shifter is in the index position for that gear.
The sram mech feels chunkier and better made. Even in detail, like the limit screws are bigger, the b tension adjuster is an actual allen key bolt rather than a screw, and the cage just feels stronger and better quality.

I'm thinking the shitmano shifter must have had it, as every other possible reason for the crap shifting has been eliminated - can't be that i'm setting it up wrong, as the sram setup works absolutely fine first time. Can't be the new mech as it's brand new. Can't be the cables as they're new(ish). so by process of elimination the shifter must have in some way had it.

my scott is now my only bike with shimano gears, and that has got a new rear mech after the old one SNAPPED clean off right through the body at the point where the limit screws go in.

these two pieces of misfortune are leading me to the general opinion that shimano gears are shite ...

 

[Globalti]

Perhaps the lower grades of Shimano aren't so good. I had an XTR rear mech, which gave me about 7 years of service on 3 MTBs in gritty wet Lancashire conditions before I judged that the parallellogram was becoming sloppy enough to inhibit grear changing. Even when slightly worn the action remained fantastically smooth.

 

[bonj2]

Perhaps the lower grades of Shimano aren't so good. I had an XTR rear mech, which gave me about 7 years of service on 3 MTBs in gritty wet Lancashire conditions before I judged that the parallellogram was becoming sloppy enough to inhibit grear changing. Even when slightly worn the action remained fantastically smooth.

maybe, but this was a Deore XT mech

 

[Joe24]

Are you sure it wasnt a fake one you got from some 'bike shop'?

 

[yello]

maybe, but this was a Deore XT mech

Surprising that. My old MTB is still running Deore XT... I have always thought it offered a good compromise between price and reliability.

 

[Globalti]

The symptoms you describe can be caused by a sticky cable, they do wear pretty fast at the curve round to the derailleur. I replace that section of outer every 6 months. Maybe the SRAM derailleur is just less sensitive to this?

Generally I don't think many cyclists will agree that Shimano kit is carp; so much of it is giving excellent daily service in terrible conditions and with no maintenance. Of course there's the snob value of rubbishing the kit that most people use while hinting darkly that you've got something more exclusive and better but that's just playground boasting translated to the web.

 

[Tim Bennet.]

I never understood the rapid rise idea though. It always more unreliable than the normal version.

 

[GrumpyGregry]

yeah it's obvious that shimano stuff is shite - must be why so many cyclists use it, even some pro's from what I've seen. bunch of know nothings obviously.

MTB'ing involves cycling in a cycle hostile environment. stuff breaks. stuff wears out, stuff goes out of adjustment. almost every component bar the frame is surely to be regarded as a consumable?

 

[02GF74]

never had a problem with shiman rear derailuers - used LX and XT.

one XT lasted 10 or more years, even with sloppy worn jopints shifted well ... but the main spring lost tension so could not get lowest geat - replaced it after it could not shift to the lowest 2 gears.

I have one bike with non shimano gears - SRAM - but these are top of the range - X.0 - have to say they shift nicer than shimano, well the rear one did until I bust it yesterday It looks to me that SRAM have a product that is at least if not surpasses shimano.

 

[Globalti]

Don't some Shimano derailleurs have an adjustment screw, which enables you to increase the spring tension? It's a big wide screw that turns an eccentric post at one end of the main spring.

 

[simon_brooke]

The reason SRAM mountain bike derailleurs work better is simple: they pull more cable for each gear change, so the tolerance doesn't need to be quite so precise. Which, when you consider that the precision is what arises out of passing a steel cable through between 0.5 and 1.5 metres of flexible sheath, matters.

The Shimano system's vulnerability to small changes in sheath length led to the change from the traditional bowden cable sheath (as we still use for brakes, but which is very slightly compressible) where the reinforcement is a tightly wound helix with wire running more or less at right angles to the run of the cable, to a very lazy spiral with the reinforcement wires running nearly parallel to the run of the cable.

This works well when new but over time the cable tends to bed down between reinforcement wires at pressure points, leading to even more sloppy and imprecise shifting.

So, if you care about precise shifting, use SRAM mechs (SRAM shifters for Shimano mechs won't solve the problem, since they pull the Shimano amount of cable), and change your cable outers frequently.

 

[peanut]

The symptoms you describe can be caused by a sticky cable, they do wear pretty fast at the curve round to the derailleur. I replace that section of outer every 6 months. Maybe the SRAM derailleur is just less sensitive to this?

.

very good point timely made my dear Raider

actually I was just about to make a post about this very point .

I have been having trouble with shifting on my 105 rear mech (nearly new) especially in the middle of the cassette where it has jumped in and out of gear and tried to climb out of gear etc. All the symptoms that Bonj described.

I oiled the mech pivots and cables reset all the settings including B screw carefully several times just like Bonj no joy.

Absolutely fed up with this because the last thing you want when climbing out the saddle is your gears slipping and jumping grrrrr

Stripped everything off the bike put it back on checked the cable alignment and noticed that the ferrule on the rear stay for the rear gear cable was bent .wtf ?
Realised on close inspection that the boss had been soldered on out of line ??

I drilled the boss inline so the ferrule on the end of the cable sat straight in line with the rear stay eliminating the sharp bend in the cable and presto perfect working gears again.

 

[swee'pea99]

My 600s have always run faultlessly...and I'm not exactly Mr Maintenance.

 

[Globalti]

The reason SRAM mountain bike derailleurs work better is simple: they pull more cable for each gear change, so the tolerance doesn't need to be quite so precise. Which, when you consider that the precision is what arises out of passing a steel cable through between 0.5 and 1.5 metres of flexible sheath, matters.

The Shimano system's vulnerability to small changes in sheath length led to the change from the traditional bowden cable sheath (as we still use for brakes, but which is very slightly compressible) where the reinforcement is a tightly wound helix with wire running more or less at right angles to the run of the cable, to a very lazy spiral with the reinforcement wires running nearly parallel to the run of the cable.

This works well when new but over time the cable tends to bed down between reinforcement wires at pressure points, leading to even more sloppy and imprecise shifting.

So, if you care about precise shifting, use SRAM mechs (SRAM shifters for Shimano mechs won't solve the problem, since they pull the Shimano amount of cable), and change your cable outers frequently.

Fascinating post thanks; I knew that but had never thought about it.

 

[bonj2]

Are you sure it wasnt a fake one you got from some 'bike shop'?

ah yeah, I got it from evans so it must be.