Oh god, is this a stupid question on rapid rise?

Alison

Retrobike Rider
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I'm not sure of the difference b/w rapid rise and non rapid rise, when to use either or what considerations need to be taken into account. I just put the mech on and hope it does the job and up to now they have, I don't think I've used rapid rise on my retrobikes, I did use a 9 speed on my husbands tourer but don't know if it was rapid rise or not.

So could I request an explanation please?

Many thanks

Alison
 
[wiki]

Derailleur Relaxed position:

High normal or top normal rear derailleurs return the chain to the smallest sprocket on the cassette when no cable tension is applied.This is the regular pattern used on most Shimano mountain, all Shimano road, and all SRAM and Campagnolo derailleurs. In this condition, spring pressure takes care of the easier change to smaller sprockets. In road racing the swiftest gear changes are required on the sprints to the finish line, hence high-normal types, which allow a quick change to a higher gear, remain the preference.
640px-SRAM_Rival_rear_derailleur_-_bottomview.jpg


Low normal or rapid rise rear derailleurs return the chain to the largest sprocket on the cassette when no cable tension is applied. While this was once a common design for rear derailleurs, it is relatively uncommon today. In mountain biking and off-road cycling, the most critical gear changes occur on uphill sections, where riders must cope with obstacles and difficult turns while pedaling under heavy load. This derailleur type provides an advantage over high normal derailleurs because gear changes to lower gears occur in the direction of the loaded spring, making these shifts easier during high load pedaling.
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[/wiki]

addition: Rapid rise derailleurs seem also to be prefered in combination with Shimano dual control levers (the brifters).
 
I've used RR on one bike only for 4 years or so. It's fine as long as you remember the gear changes are "opposite" to what you may otherwise expect on non RR mechs. Apart from that I can see little in the way of advantage/disadvantage.
 
I have an XTR Rapidrise rear mech. on my Explosif, pulled by a 9-speed SJS 'thumbié,' and it works fine...

...appearance wise there is no real difference as far as retro aesthetics are concerned :cool:
 
One would from a non-engineer's view point expect the mechanics of rapid rise/low normal to be an advantage in terms of ease of shifting (the spring is helping in moving "uphill" on the cassette). IME it DOES - and yes they work well with thumb shifters, especially non-indexed.
 
I'm just glad someone asked the question, up until then I thought it was something to do with viagra
 
They're not pushing the chain 'uphill'. Virtually all modern mechs have slant parallelogram geometry to they're pushing the chain along the imaginary cone that delineates the face of the cassette.

As such any difference was minimal, and counter intuitive to many riders as the rest of the world still ran top normal. As a consequence customers left Shimano in their droves and defected to SRAM, and it was Shimanos sudden adoption of low normal that suddenly put SRAM in the big leagues in the quality component market.

It couldn't have been that good idea because Shimmy backtracked quickly and dumped the system, but the damage was done and they've never regained their previous market share.

As for myself I don't dislike it. My XtC950 is rapid rise XTR and the gears work ok, but they're not any better than the gears on my other 7 bikes.

Not a bad idea, just an unwanted idea and 20 years too late. An answer to a question no one had asked since the 70's.
 
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