Rear mechs-mixed shifters

[dyna-ti]

I was in the LBS today,looking at x9 shifters.
Im wanting to use these with an m772 XT rear mech

Bike shop says theyre not compatible,then mumbled on about the 1.1 ,2.1 thing.

To me this sounds complete crap,
I understand sram shifter pull a different amount of cable to shimano,but it's the shifter that determins the amount of movement in the rear mech,not the rear mech itself.
You set the high/low then click away .

I would think the only things affected by actuation would be the shifter and the cassette.

Correct yeah :?

 

[barry2017]

Unfortunately, he was right. They won't work together.

Sorry. :cry:

 

[dyna-ti]

But why :?
Im looking for the full,no holds barred scientific explanation here
anybody actually tried it :?

 

[jonnyboy666]

the reason it doesn't work is the action of the parallelogram on the rear mechs between the brands. they are different lengths and/or angles which cause the mech move sideways more or less than you need depending whether you are using shimano shifter with sram mech or sram shifter with shimano mech.

edit, yes i have tried it in days gone by when the sram mechs first came out, and i have deliberately done it to show customers it doesn't work when they haven't believed me when i was working in the trade.

i don't know if sram still do it but they did do shimano compatible shifters, why not just use one of them? the only reason i don't know if they still do the attack(?) shifters is coz in all honesty i can't stand sram componentry! since i left the trade nearly 2 years ago i don't have to know about that stuff so don't bother anymore!!

shimano works and is easier to get hold off and by comparison i think it lasts longer.

my 2p.

 

[FluffyChicken]

A shifter pull an amount of cable.

The rear cassettes are ~the same width with same spacing between the cogs.

If the shifter pulls a different amount of cable through in 1 click, then there has to be another part that reacts to that amount of cable pull, yet still only move the same distance.

Hence the rear mech needs to be designed slightly differently to cope with that.

Think about it, if all things are the same other than the amount of cable it pulls.
Mentally pull 1cm then 0.75cm, then 0.5cm then 0.25cm. Now think would this work the same at the rear end (all being the same) if I pull 0.625cm, 0.625cm, 0.625cm, 0.625cm ?
Of course not, you would start and end up at the same place, but everything in between would be wrong.



This is different to the Shimano/Suntour 'Retro' talk. There the shifter pulls a different amount of cable per click, yet the mechs are pretty much the same. In this case the cassette and their spacing are different to

 

[cyfa2809]

thanks for the explanation! yes they still do attack shifters although i thought these were 1:1 actuation? you can get sram trx which arent to bad and shift 2:1, i use my trx shifter with an alivio mech and it does the job

 

[dyna-ti]

thanks for that guys.It makes better sense now

ill stick to the shimano shifters

Next problem-
why the hell does the XT m772 rear mech have a pivot bolt that swings :shock:


I dunno,bloody things are getting too modern,LBS mechanics must be getting to me,with their fancy bikes :?

Sigh

 

[Lysander]

Aye- SRAM shifters with names are Shimano compatible, numbers urnae!

 

[cyfa2809]

Aye- SRAM shifters with names are Shimano compatible, numbers urnae!

is this actually true? really? everything with a name works???

 

[Lysander]

Far as I understand it, and Dave the GrippyShifties, Ted and Albert the SRAM levers works fine mit der Shimano.......