1:1 Sram v 1:2 Shimano activation ratio
- Thread starter jungle
- Start date
basically the cables in a sram system moves twice the distance a shimano system would on each shift. so that means less force for each shift, its more precise and there is more room for error. thats why pll talk about it staying perfect for longer.
dhkid said:
That didn't make much sense.
I feel it has more to do with the way the derailleurs and shifters are designed than the accuation ratio. The shifters click back really fast and feel crisp and they shift quickly. The derailleurs have a stiffer spring in them than the shimanos and add to that crisp quick shifting feel. And the sram derailleurs don't explode and leave dents in your chainstays.
I agree that I like SRAM much more, but exploding Shimano's leaving dents in your chainstay?!? Did you switch out lube for nitroglycerin?
bballe336 said:
dhkid said:
SRAM's ESP design uses a 1:1 ratio. This means that for each millimeter of cable moved in the shifter, an equal millimeter will be moved in the derailleur. Conversely, Shimano uses a 1:2 ratio for it's shifting systems. This means that for every one millimeter of movement in the cable there will be two millimeters of corresponding movement in the rear derailleur.
Your shifter cable is somewhat elastic and stretches (both during a shift and over time), housing wears, etc. These factors can contribute to your shifting going out of whack.
A 1:2 ratio means that every distortion of the cable results in 2x the amount of corresponding derailleur deflection.
In practical terms, this means that if one were to compare 2 freshly tuned derailleurs systems---one 1:1, the other 1:2---you would notice no difference. Given equal amount of wear and use, however, the 1:2 system will mis-shift sooner as the effects of cable strech make more of an impact on the position of the derailleur.
Also, (and this may not matter to many people), 1:1 systems are easier to tune, and work more reliably for longer cable runs.
I have only had good experiances with SRAM, and only bad experiances with Shimano.
I don't know if its just luck, or if its the activation ratio, but i'm definantly sticking with SRAM!
I don't know if its just luck, or if its the activation ratio, but i'm definantly sticking with SRAM!
IronDad said:
No. No they're not. If a derrailleur is a certain amount out, you need to move twice the cable to correct it, so your barrel adjusters are less effective than on a Shimano system. This problem is compounded by the fact that Sram insist on omitting the barrel adjuster on some rear mechs, leaving you with half the adjustment to do twice the work.
I agree that 2:1 is a good idea in terms of staying sweet for longer, but it's not without it's shortcomings.
You've got it backwards. The barrel adjusters are even more precise and more effective for fine tuning as they are pulling less cable at the derrailleur/shifter.big-ted said:
It just means you have to not be lazy and use a friggin allen key when setting it up the first time. Oh wait...you have to anyways.
touché...Transcend said:
It depends on your point of view I suppose. Personally, I'd rather have a greater range of adjustment than greater "precision" as you put it. I'm more than capable of making fractions of turns with my fingers.
In addition to some of the other information out there;
Shimano has a 1.7:1 ratio, sram is around 1.1 to 1.2:1, their marketing department isn't exactly fair with this feature.
Shimano's ratio also means shorter pushes with the levers for shifts, although this can be compensated for in the shifter, it will add weight and complexity when you're trying to shorten the lever throw of a "1:1" system.
Which system stays in adjustment longer or is better is also not cut and dry, the tolerance of the detents within the shifter plays a huge role. The old gripshift SRT stuff was absolutely terrible, and the detents would wear out quickly, which is why they went to 1.1:1, that allowed more room for error with their plastic detents. This is not so much an issue any more, but a high percision system could still be 2:1, and still stay in adjustment longer, just depending on the percision of the detents and the material they are made out of (for wear).
Shimano has a 1.7:1 ratio, sram is around 1.1 to 1.2:1, their marketing department isn't exactly fair with this feature.
Shimano's ratio also means shorter pushes with the levers for shifts, although this can be compensated for in the shifter, it will add weight and complexity when you're trying to shorten the lever throw of a "1:1" system.
Which system stays in adjustment longer or is better is also not cut and dry, the tolerance of the detents within the shifter plays a huge role. The old gripshift SRT stuff was absolutely terrible, and the detents would wear out quickly, which is why they went to 1.1:1, that allowed more room for error with their plastic detents. This is not so much an issue any more, but a high percision system could still be 2:1, and still stay in adjustment longer, just depending on the percision of the detents and the material they are made out of (for wear).
One huge advantage with SRAM is the way the cable is routed through the rear derauilleur, eliminates that big loop of cable housing of the Shimano set up. Less chance of getting that caught up in something.
It just seems that on all the DH bikes I have had, the SRAM works better.
It just seems that on all the DH bikes I have had, the SRAM works better.
DIRTWRKS said:
Very true. That loop on the shimano setup is far more likely to catch on something than the SRAM routing.
Furthermore as others have stated. The 1:1 ratio is less likely to mis shift due to the cable/housing being out of adjustment. It is also less likely to mis shift when the suspension compresses due to the housing being bent.
Heres my way of explaining it... Using a cable and housing as a way to transfer motion has its drawbacks (cable stretch, flex). The cable flexes when it is under a high tension. The shimano system puts more tension on the cable, and doesnt pull as much per shift. SRAM uses more pull distance, and less tension on the cable per shift, less affected by cable flex. The SRAM system puts the leverage at the derailluer, not at the shifter like Shimano does. The "Shimano Loop" also creates alot of friction compared to SRAM's straight shot routing.
i never realized that haha. but now i just have one more reason to like SRAM 10X better than shimano.DIRTWRKS said:
There's always the avid rollamajig to eliminate the 'shimano loop'
I run SRAM, but I just like the word rollamajig too much to miss a chance to mention it
I run SRAM, but I just like the word rollamajig too much to miss a chance to mention it
At least you just said that to use the word.. because rollermajigs are still useless compared to the Sram system.Darkreaper said:There's always the avid rollamajig to eliminate the 'shimano loop'
I run SRAM, but I just like the word rollamajig too much to miss a chance to mention it
True, but still...
SRAM >> Rollamajig > Shimano loop
SRAM >> Rollamajig > Shimano loop
Has anyone ever actually done this? Wtf would you snag it on? You'd have to be riding through shrubberies to catch the thing.DIRTWRKS said:
If you're not a hack about setting up cable housing, you don't have a big huge loop. It really doesn't have to stick off the frame very far. If you are a big hamfisted mechanic and put a big f'in loop of housing sticking off your frame, that YOUR fault, not Shimano's.
I think SRAM's cable routing system is superior, but people just like to fling poo at Shimano because they're a huge company. It's pretty rad that there are two great shifting systems to choose from.
Darkreaper said:
It's funny seeing as how avid is sram, and sram had to develop something to help with shimano's little issue.
I've destroyed 3 XT deraillers this way, so yeah... to say the least.Smelly said:
There's still a little bit more to it than is being talked about.
Everyone who has a SRAM derailer (which is a functional copy of the Sachs stuff) should twist it backwards where the bolt goes into the derailer hanger, and then let it go. Notice how it SLAMS into it's stop. All that force is being absorbed by the derailer due to the design, and yes it keeps the chain from moving much and allows for a non-moving/no-loop cable interface, but I don't think shimano would ever make a similer design. The shimano derailer moves back and forth easily, and all of those stresses are being dissipated, instead of transfered right into the knuckle area or derailer bolt area of the derailer.
This might not be a big deal for some, but every broken sram derailer has always been in this area, and they've all had the same basic design. I'd chaulk up the failures that I've had to this fundamental difference between the two derailers.
There's definitely good things about the sram system, 1:1.1 for whatever purpose the originally designed it, can allow for more precision and may not go out of adjustment as easily. There's also things about it that may not be as good as the competition, so when it comes down to it, you have a choice and either side has some advantages and disadvantages.
Everyone who has a SRAM derailer (which is a functional copy of the Sachs stuff) should twist it backwards where the bolt goes into the derailer hanger, and then let it go. Notice how it SLAMS into it's stop. All that force is being absorbed by the derailer due to the design, and yes it keeps the chain from moving much and allows for a non-moving/no-loop cable interface, but I don't think shimano would ever make a similer design. The shimano derailer moves back and forth easily, and all of those stresses are being dissipated, instead of transfered right into the knuckle area or derailer bolt area of the derailer.
This might not be a big deal for some, but every broken sram derailer has always been in this area, and they've all had the same basic design. I'd chaulk up the failures that I've had to this fundamental difference between the two derailers.
There's definitely good things about the sram system, 1:1.1 for whatever purpose the originally designed it, can allow for more precision and may not go out of adjustment as easily. There's also things about it that may not be as good as the competition, so when it comes down to it, you have a choice and either side has some advantages and disadvantages.