J-McKech

Im curious to understand these terms. In a couple of posts in the recent past we have talked about SRAM having 1:1 ratio while Shimano has 2:1 and people needing to replace shifter pods and what not. Also, we talked about Shimano's rederailuer being rapidrise. So what all does this mean?

Maelstrom 

Rapid rise is simple ass backward. You push on the THUMB deraileur to make the gears HARDER....normal and what makes sense, does the opposite. Its all done for durability...but, in my durnken state, screw durability...give me something that makes sense. You never need to grab a handfull of gears going down as most people are braking too much anyways...you always need to grab a handfull of gear going up (easier gears) if you don't know the trail...

Rapid rise is built for xc guys who study trails and know them, it is NOT build for people who ride anything and everything...(especially dhillers and freeriders...RR is just a dumb system. It doesn't work for everyone. Shimano should pull their heads out of hteir corporate non riding butts and create both, equally. Neither system is perfect, both systems are correct...)

Raiyn

Rapid rise means that the derailiuer works backwards when you release cable the derailieur climbs into a lower gear. Shimano shifters need to pull twice as much cable to effect a shift than SRAM does
The only thing that should be Rapid Rise is yeast

PWRDbyTRD

wait...haha you mean to tell me that I will have to push to go into a harder gear?

Raiyn

With the new Shi*No yes, with your new Sram hell no

Maelstrom 

yes

PWRDbyTRD

wait wait..ok I just got my SRAM stuff..it's sitting on my desk. I have to use the thumb lever or the index finger level to move to a smaller cog?

J-McKech

I think they are saying with the sram you would pull the index finger to move to a smaller cog, while on shimano you would push the thumb lever.

Raiyn

SRAM is both thumb levers

khuon

The ratios are actuation ratios meaning that in a SRAM system a pull of the cable of a certain length produces an exact linear equivalent movement of the derailleur. In a Shimano system, you need to pull twice as much cable.

Rapid-Rise is Shimano's term for what is more generically known as a low-normal derailleur. Traditional derailleurs operate in a high-normal mode which means the spring is setup so that if there is no tension on the cable, the derailleur will want to proceed towards the higher gear ratio (smaller cog). In a low-normal derailleur, in the absence of cable tension, the derailleur will want to travel in the opposite direction towards the lower gear ratio (bigger cog).

PWRDbyTRD

which lever moves you UP the cogs

khuon

Here's what I posted in another thread about Rapid-Rise.

Rapid-Rise sucks in many ways, IMHO. For the non-XC racer who hasn't had a chance to go over and preview every trail/course, the Rapid-Rise introduces many annoyances beyond just having to rethink which direction to shift. The first is that you have to click your way in the downshift direction one gear at a time. This can really make or break clearing an obstacle or setting up a line or maintaining your speed/cadence when climbing a hill that's surprised you. Another thing is the gate-lag which means that you have to rotate through a certain arc before the shift actually happens regardless of when you initiated the shift from the shifters... and this happens on the downshift. Also, this gate-lag is more apparent when you're moving slowly. That is the rate at which you can shift is dependent on how fast the rear wheel is moving. Additionally, you can compound the problem when trying to force a shift. You can force the shift with traditional derailleurs no-problem but if you do it with Rapid-Rise and miss the gate then you succumb to the lag. Also, another problem with Rapid-Rise is that it is more prone to mis-shifting in the downshift direction when the cables or mechanism gets gunked up. Basically, Rapid-Rise favours upshifting but does so by sacrificing downshift performance. And as most MTBers can testify, it's usually more critical to hit the downshift than the upshift unless you're on a well-known trail in an XC race.

HDTVKSS

so tell me this, is shimano still making non rapir rise shifters ( AFAIK XTR is still availiable in non rapid rise....) the double thumb movement on SRAM doesnt sound to appealing either...

khuon

Someone correct me if I'm wrong but I don't think Shimano is still manufacturing the RD-M952 which was the last XTR-level high-normal rear derailleur. This is from the older M95x line of XTR components. The RD-M96x series of derailleurs of the current M96x line only come in Rapid-Rise.

skunkty14

The paddle in the left of the picture, or the lower paddle as the shifter is mounted on the bike.

Rapidrise uses reversed shifter action, but you don't have to worry about that; Rapidrise is Shimano only, SRAM still uses the derailler action you are used to.

willtsmith_nwi

Actually, with Shimano it's the opposite. A 1mm pull in Shimano will produce 2mm of derailleur movement.

This design is inspired by the original trigger shifters. Little wheels inside shifting pods dictates less cable pull.

SRAM by contrast originally introduced 1:1 ESP to make their large radius grip shifters easier to build. The result was a system less sensitivie to cable slop.

Put it this way ... a 1mm snag/stretch in a Shimano line will produce a 2mm index error at the derailleur. In SRAM, 1mm of cable snag will produce 1mm of index error. Put simply, Shimano 2:1 shifting amplifies any error by a factor of two.

willtsmith_nwi

This is aimed at shutting SRAM and others out of replacement shifter market for Shimano Derailleurs. I think it's backfiring though. More people are rebelling and going SRAM.

phantomcow2

YOu use your thumb to move up. The lever that moves horizontally, it pushes out. Use your thumb to push there and your index to bring the other lever upwards to shift down. I dont know if thats how its supposed to be done but i cant see any other way

PWRDbyTRD

I just got sick of Shimanos bouncy, lagged shifting and figured I might as well try something if everyone raves about it

khuon

Thanks for the correction.

PWRDbyTRD

so why does it take 3 pushes to make it up the cogs with the shimano but only 1 with SRAM?

khuon

Don't confuse throw length on the lever with actual cable pull. The ratio there is not 1:1.

TimB

SRAM cable pull ratio is a marketing gimmick to make themselves different whereas Rapid rise or Low normal has functional benefits.

I can see nt many have actually used a Low normal derailleur. If you have you will realise that the "surprise" scenario you talk about when suddenly encountereing a hill on the course or trail is actually easiet to effect th downshift with a Low normal derailleur. Why?

you're coming down the hill take a bend and are confronte with a hill.
With a High Normal derailleur you try to force the chaina few sprockets at a time to downshift. The net result is the chain is not effectively engaged on the teeth and sufferes damage which later leads to breakge. The shift is still slow because youhav to soft pedal to make the shift work.

With a Low nrmal derailleur, the spring tension pulls the chain up agianst the shift ramps and the lower gear ratio is effecte. a few clicks and you're in a lower gears without forcing anything.
Downshifts can be jst as wuick anyways an areonly limited by how fast you can flick the release lever. The spring tension will ensure that the chain does not move too fast to risk damage or breakage.
Overall I fing a low normal (Rapid rise system) to be faster than a conventional system.

I've been using RR derailluers for 4 yrs and they are better than the ESP derailleurs i've had on my 2nd bike. Also had zero chain failures with a RR system.

serious

I have the Low Normal XT setup on my bike and I have gotten used to it with few problems. I believe that Low normal is clearly a better setup, especially for recreational riders. If you are not an old dog who needs to learn new tricks, it should be a no brainer!

For non-racers, and most of us fall in that category, downshifting is generally more important (critical) than upshifting. Low Normal allows you to do that in a controlled manner - no need to soft pedal or hesitate. Just use you thumb to click your way into lower gears. And you can pre-click while coasting!

And khuon you have it wrong. Downshifting is easy and you can downshift several gears at a time. Just push the break lever way down. So when faced with a downhill section Low Normal can get you several gears higher in a hurry.

If you are objective about the whole thing, Low Normal makes a lot of sense. If you resist re-learning to shift, you will find a 1000 problems with Low Normal - most of them related to the fact that you are not willing to re-learn gear shifting.

PWRDbyTRD

you're talking about flippies aren't you?