Retrobike Forum Index

It is currently Sun Dec 04, 2016 5:26 am

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Thu Feb 28, 2013 4:39 pm 
Karma Queen / Cake Meisterin
Karma Queen / Cake Meisterin
User avatar

Joined: Thu Jul 27, 2006 10:02 pm
Posts: 6736
Location: North Yorkshire
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


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 4:49 pm 
Old School Hero
User avatar

Joined: Sat Dec 16, 2006 11:24 pm
Posts: 191
Location: Netherlands
[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.
Image

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.
Image


[/wiki]

addition: Rapid rise derailleurs seem also to be prefered in combination with Shimano dual control levers (the brifters).


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 4:54 pm 
P.o.T.M. Winner / MacRetro Rider
P.o.T.M. Winner / MacRetro Rider
User avatar

Joined: Fri Jan 23, 2009 1:03 am
Posts: 5502
Location: In the foothills of the foothills of The Cairngorm Massif :D
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.


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 5:10 pm 
Old School Grand Master
User avatar

Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
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 8)


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 8:53 pm 
Gold Trader
Gold Trader

Joined: Wed Feb 04, 2009 9:40 pm
Posts: 2157
Location: Nottingham
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.


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 10:18 pm 
Old School Grand Master
User avatar

Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
...FWIW the indexing with the SJS 'thumbies' is very precise 8)


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 10:44 pm 
Gold Trader
Gold Trader

Joined: Wed Feb 04, 2009 9:40 pm
Posts: 2157
Location: Nottingham
Sorry, I didn't mean to imply that DON'T also work well with indexing!


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 10:49 pm 
Old School Grand Master
User avatar

Joined: Sun Sep 05, 2010 1:10 am
Posts: 4756
Location: Heathfield, East Sussex
...ditto; all I meant was the SJS 'thumbies' are a good match to the mech. 8)


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 11:06 pm 
eBay Outing Master
User avatar

Joined: Sat Nov 21, 2009 3:53 pm
Posts: 8000
I'm just glad someone asked the question, up until then I thought it was something to do with viagra


Top
 Profile  
 
PostPosted: Thu Feb 28, 2013 11:41 pm 
Retro Guru
User avatar

Joined: Thu May 03, 2012 7:13 pm
Posts: 2574
Location: The Cock Inn, Tillett, Herts
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.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 15 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: Carsen80, Majestic-12 [Bot] and 14 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group