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Techno advice

By Andy Bloot - Posted on 07 June 2007

NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.

Can anyone tell me the difference between an 11-32T and a 11-34T cassette?
And what is a top normal, and a non-rapid rise derailleur?
I've killed an LX drivetrain through lack of knowledge and Sydney sand and thinking of ebaying an XT spec. Everything is Shimano, but would consider SRAM if better for the money.
I need help.


Erm... this sounded a real easy question, but then you made it way hard by asking about rapid-rise Eye-wink

I'd spec an 11-34 cassette as I like to be in mega low granny gear for grinding up hills (the 34 over 32 teeth on the back helps here).

Having just gone from Shimano to SRAM have to say I like the SRAM, but can't comment on it's long term reliability. It wasn't that hard to adapt to, and dare I say, may be a convert. There's a bit of religious war about the two as you can imagine so will try to keep to the facts (erm... if you can call the hear-say I've stumbled across 'facts'):

SRAM have this 1:1 actuation ratio thing on the rear (both SRAM and Shimano use 1:1 on the front). AFAIK, 1:1 refers to the cable/derailleur movement: you press the shifter's leaver, it pulls 2mm of cable through the outer and the rear derailleur moves 2mm.

Shimano have 2:1 actuation which means to move the rear the same 2mm, only 1mm of cable needs to be pulled. This is supposedly more prone to dirt and stuff in the cable as the spring on the rear doesn't have to be as strong ('cos it's pulling less cable), and the adjustment has to be more accurate than on a 1:1 SRAM thing. Because the SRAM rear has stronger spring holding it in place it's meant to jump and skip about less through bumps.

I think 'rapid rise' is Shimano's way of explaining the difference, but someone will be along to do a better job on that shortly I'm sure.

I doubt there's any real performance diff that us mere mortals can appreciate on either system so shop around (T7, Phantom, eBay, etc) and pick up a nice deal on good parts. Shame, T7 had the bling (red spider) 990 cassette for 70 bucks last week or something Eye-wink

Don't forget if you are replacing the whole drive train to change front rings, chain, cassette (and sometimes even jockey wheels). Erm... which makes me think you're maybe going to keep the derailleur and all the stuff I just said was pointless. Oh well, never mind! Eye-wink

I think Rapid Rise is to do with which direction the spring is mounted on the rear derailleur. With a normal one if if you release cable it shifts the chain to a smaller cog. With a rapid rise/low normal shifter it shifts to a larger/lower gear when cable is released.

SRAM and Shimano rear derailleurs and shifters are not interchangeable as far as I am aware.

All info is good info- though I had to turn my music off to really try and understand it. My jockey wheels are cactus as well, but as I'm looking to sell the bike before years end, will keep the rear derailleur at least for the time being.
I saw that cassette on T7, and it did look blingy, but had no idea if it was what I needed.
A new 06 Deore XT 9S HG Casettes CS-M760 11-34T Sprockets is selling on ebay for around $70, but the only thing that means anything to me is the XT- and now the 34T. So many damn numbers and letters I get confused with them all.
Your help is very much appreciated.

I use 11-32 cassette as I find 11-34 just too low, count the teeth on your cassette and if you want a slight change do so.
The rapid rise rear deraileur works backwards to the normal or original deraileurs these are also called top normal because with no cable tension they will go to your top gear. Rapid rise with no cable tension will go to your lowest gear. rapid rise works great with duel control shifters, but other than that I wouldn't buy rapid rise as I think it was designed to make the duel control shifters feasible.
Sram vs shimano all good but I don't like sram cassettes for longevity (maybe?)
John Evans

So for your racer legs John go the 32 tooth
And for my puny chicken legs go the 34 maybe
How's the hand and knee by the way
Gonna have to take it easy old man
Ha- never

I'm sitting at home a lot but I'm coming back harder and faster, forcing myself to 90min a day on my exercise bikes, yes I have 2.
Riding my bike doesn't work with one hand, trust me I've tried.
And I think you better stick with 34 teeth on the back, in fact see if you can get more!! ;o)

I was wondering

Not on the back. that would be huge and you'd be going so slow you'd fall over.

44t would be a front ring. Most cranks run 22 granny gear,32 middle ring and 42 or 44 big ring. riding in thee 22 tooth granny gear and 34 tooth sprocket at the back is about walking pace if not slower.

rapid rise was made so that if you pull on the cable you go into a harder gear. Shimano claim this has several benefits. The only one I can see is that it means that it is the same as the front shift, ie push with the thumb to get a harder gear.

It then relies on spring tention when you want easier gears. Personally I think that is silly as it's when I hit a sharp hill that I want to be able to hit the lever with my thumb and go back a heap of gears at once to find an easy gear as ion rapid fire (conventional). Also if the cable is gritty and sticking in the outer I want to be able to force the change to an easier gear not be reliant on the spring tension.

As of SRAM and longevity. I've been running it for a while now. On my DH bike I have been through a X9 shifter quick than I thought I should but one my Xc bike the X9 shifters and X0 deraileur are about 2 years old and going strong. I've put an 990 cassette on about 1 year ago but that was more a matter of a bling upgrade than a needed replacement.
The gerneration front deraileur is a bit of a let down and I've gone through 1 already but I'd be interested to see how the x9 goes.

I haven't heard / seen a 11-34 T cassette only 11 - 32 and 12-34.

My Kona has 11-32 and my enduro has 12-34 and there is a huge difference, not helped by the fact that the chain rings are also different, only two on the enduro and they are bigger. I find the Kona much more "efficient" to ride, apart from the weight, the gearing just feels so much better.

As for rapid rise, I may have missed someone else saying this as I only skimmed the previous posts but my take is Shimano Rapid Rise lets you change up 2 cogs with the one push of the lever. As I said I could be wrong on both counts.

I am a shimano fan through and through and nothing will change my opinion on that, but thats all it is, my opinion. I know others are equally in favour of SRAM but I hate the stuff, doesn't last anywhere near as long and the only chain I have ever broken was an SRAM and no it wasn't that old. I got about 3 years out of the Kona drive train before I had to start swapping parts from wear, the SRAM didn't last a year.

True Rob the shimano is probably a little more fiddly but if you keep it serviced and clean it will serve you well. Take the time to learn how to set it up properly and you won't have problems. When you clean it slide the housing s along the cables and lube / clean these as well. The spring will have no probs if its kept clean.


11-34 is a common shimano cassette and the huge difference you notice must be due to the front chainrings as the difference between a 32 tooth and a 34 tooth is not a lot. On an 11-34 cassette the next gear has 30 teeth, so 32 is halfway.
Another thing I have done with front chainrings is once the middle ring is worn, is to replace it with a deore one as it's steel (and cheap) like most granny rings and lasts longer so it doesn't destroy your chains as quick.
Cheers John Evans

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