Bicycle Mechanics - whats the difference between medium cage and long on rear derailer

i'm looking to buy a new rear derailer and ran in-to the option for long or medium cage what the difference and what is recommended for 2003 hardrock pro

thanx

well from what I been readin seems a med cage covers 28 or 30 teeth
and long cage overs 32 and up

Shorter the cage=The quicker the shift is going to be. It has noting to relate to what the amount of teeth a cog on cogset has. If it did, me and many others would be in big trouble for using short caged deraillieurs on larger cassettes.

thanx for the help but it seems my wife wants me to take it to the shop .

Shorter the cage=The quicker the shift is going to be. It has noting to relate to what the amount of teeth a cog on cogset has. If it did, me and many others would be in big trouble for using short caged deraillieurs on larger cassettes.Well,the quicker shifting is problematic,and cage length IS. about wrap capacity

i'm looking to buy a new rear derailer and ran in-to the option for long or medium cage what the difference and what is recommended for 2003 hardrock pro

thanxCage length is about wrap capacity.For just one expampe, a shimano 9 speed medium wraps 33 teeth and the long wraps 45.

What I was trying to say that the myth about having to use a long cage on a larger cogset is false. Even with a long cage on a larger cogset, the wrap capacity is about the same as a short cage. The less wrap, the quicker the shift you will get. The difference in between the amount of wrap capacity in a long and short cage is in all actuality insignificant. You still have plenty of chain on the cog for it to work effectively. Since 100percent Marine does about the same kind of riding I do, a major advantage to running a shorter caged deraillieur is that it gives you more clearance when you are in the rough stuff..

With any 9 speed cogset, you always count everything on the 9th gear the smallest cog in size on the back. Shifting is out of whack get it to the 9th gear on the back and adjust from there. I am also 100% sure there won't be 45 teeth on the smallest cog on the back.

What .......... a major advantage to running a shorter caged deraillieur is that it gives you more clearance when you are in the rough stuff.. I can buy that part. But if your chainring/cogset has enough teeeth difference to suggest a long cage,and you opt for a short one,then you will likely forego some small cogs when in the small ring.I also know that wrap spec is conservative and you can often get away with more. I also use short cage on all my road triples, even tho the 'book' says you need a long cage.

With any 9 speed cogset, you always count everything on the 9th gear the smallest cog in size on the back. Shifting is out of whack get it to the 9th gear on the back and adjust from there. I am also 100% sure there won't be 45 teeth on the smallest cog on the back.What??

I always thought the cage length was about chain capacity - if you have a triple and a wide range rear the difference in chain length between the extreme combinations is much more than that of a double with a 12-21 cassette. Hence the longer arm and more chain for the former setup.

well maybe I'm wrong but then how come I havent seen a short or med cage rear derailes rated for 34 teeth but I have for long cage

well maybe I'm wrong but then how come I havent seen a short or med cage rear derailes rated for 34 teeth but I have for long cage You have been checking the wrong references.Try a shimano catalogue.And remember, road derailers regardless of chage length have a smaller large cog capacity than MTB RD.

I always thought the cage length was about chain capacity - if you have a triple and a wide range rear the difference in chain length between the extreme combinations is much more than that of a double with a 12-21 cassette. Hence the longer arm and more chain for the former setup. That's what wrap capacity is. Stated in teeth. (Large ring - small ring) + (large cog - small cog = how much wrap capacity you need. Stated capacity is also usually conservative,and can be fudged even more by staying out of the smaller cogs when in the granny ring.

Man, there's a lot of misinformation going on here!

Rear derailleurs have two significant capacities, largest rear cog and chain wrap capacity. They are two entirely different things.

Shimano mountain bike derailleurs are rated for 34 tooth large cogs regardless of cage length. Shimano mountain bike derailleurs are rated for 27 teeth regardless of cage length.

Shimano rear derailleurs, both mountain and road come in two cage lengths. Mountain derailleurs will wrap up either 33 or 45 teeth of chain and road derailleurs will wrap up either 29 or 37 teeth of chain. I can't subjectively feel any difference in shifting crispness due to cage length. I can't see why there would be any difference because the parallelgrams, that do the shifting, are the same.

Campy is a little different. Medium cage Campy derailleurs will handle a slightly larger rear cog as well as wrap up more chain than the comperable short cage version.

Campy is a little different. Medium cage Campy derailleurs will handle a slightly larger rear cog as well as wrap up more chain than the comperable short cage version. The campy medium is more in the spec than anything. The short will handle the large 29 just as well in almost every current application.I have some older frames with with a short hanger where that might not be the case.

Man, there's a lot of misinformation going on here!

Rear derailleurs have two significant capacities, largest rear cog and chain wrap capacity. They are two entirely different things.

Shimano mountain bike derailleurs are rated for 34 tooth large cogs regardless of cage length. Shimano mountain bike derailleurs are rated for 27 teeth regardless of cage length.

Shimano rear derailleurs, both mountain and road come in two cage lengths. Mountain derailleurs will wrap up either 33 or 45 teeth of chain and road derailleurs will wrap up either 29 or 37 teeth of chain. I can't subjectively feel any difference in shifting crispness due to cage length. I can't see why there would be any difference because the parallelgrams, that do the shifting, are the same.

Campy is a little different. Medium cage Campy derailleurs will handle a slightly larger rear cog as well as wrap up more chain than the comperable short cage version.

Basically I've covered it, but forgot to separate wrap capacity and large rear cog. It's been about 6 months since I had to go through numbers for deraillieur size and all of that, so obviously I was rusty in that area. Usually when I figure out what I like, I won't change and will just get what is needed. The last time I had to go though this stuff was back in December with the switch over to sram. So yes, I screwed someparts up due to rustyness.

Oh and I just looked through one of the books [i[Zinn and The Art of Mountain Bike Maintenance[/i] under the transmition and under section called cable tension adjustment. It says Biggest front smallest rear.(Doesn't have to do with the quoted message.

ok so you all are say for best resualts I need what a MTB read rerailer on my Road bike ?
rear cassette is 14-17-21-26-32 and Front Chainrings are 52/39
it gives me a nice ratio range from 32 to 100 :)

No, 100 percent is a mountain biker if I remember and he was asking about the mtb drivetrain.

No, 100 percent is a mountain biker if I remember and he was asking about the mtb drivetrain.What??

Oh and I just looked through one of the books [i[Zinn and The Art of Mountain Bike Maintenance[/i] under the transmition and under section called cable tension adjustment. It says Biggest front smallest rear.(Doesn't have to do with the quoted message. What??

ok so you all are say for best resualts I need what a MTB read rerailer on my Road bike ?
rear cassette is 14-17-21-26-32 and Front Chainrings are 52/39
it gives me a nice ratio range from 32 to 100 :)
Yeah, a mtb will handle the 32 with no issues and a medium cage will handle all the chain wrap you are dealing with. There use to be old road derailers that would handle 36 and 38 big rear cogs,but they are hard to find and only work with friction.

Maybee we should actually answer the question he(100 Percent Marine) initially asked what deraillieur size would be recommended, then another came in assuming that the road transmition is the same thing as a mountain bike transmition. The theory is the same but the tech is in completely opposite(Well now with shimano bringing the rapid rise stuff over to mountain from road, which has blurred the lines.) directions. The tech in mtb transmitions has been designed starting at a 38 down to 32. Road bikes go from 32 down if I remember. Eventually it will all be the same. Yes a mtb can handle a 32.

To answer 100%'s question it doesn't really matter, it all depends on how hard you want to pedal.

To answer 100%'s question it doesn't really matter, it all depends on how hard you want to pedal.I don't think so. If his wrap requirtments dictate a long,then that's what he should get.

Maybee we should actually answer the question he(100 Percent Marine) initially asked what deraillieur size would be recommended, then another came in assuming that the road transmition is the same thing as a mountain bike transmition. The theory is the same but the tech is in completely opposite(Well now with shimano bringing the rapid rise stuff over to mountain from road, which has blurred the lines.) directions. The tech in mtb transmitions has been designed starting at a 38 down to 32. Road bikes go from 32 down if I remember. Eventually it will all be the same.
What?

Maybee we should actually answer the question he(100 Percent Marine) initially asked what deraillieur size would be recommended, then another came in assuming that the road transmition is the same thing as a mountain bike transmition. The theory is the same but the tech is in completely opposite(Well now with shimano bringing the rapid rise stuff over to mountain from road, which has blurred the lines.) directions. The tech in mtb transmitions has been designed starting at a 38 down to 32. Road bikes go from 32 down if I remember. Eventually it will all be the same. Yes a mtb can handle a 32.

To answer 100%'s question it doesn't really matter, it all depends on how hard you want to pedal.

There is almost nothing in this post that makes sense to me.

There is almost nothing in this post that makes sense to me.There was nothing in it that made sense to me.

dang!!!
i wish i didnt have to drive to VA. i would have like to be here for this conversation, i just dropped it off at the shop cause my wife didnt want me messing it up and i went with the original hardware, deore XT . i crushed my set while shifting to go up thsi hill called monster, man was i POed

the bike shop guy said that it didnt really make a diff long or short accept for my pedaling.
thanx for all your help and all the good ideas about derailer technology i think i understand a bit more about my bike

the bike shop guy said that it didnt really make a diff long or short accept for my pedaling.
What?

i'm sorry i was talking about he cage issue, medium or long cage

Y'all drink to much coffee. Replace it with whatever was on there.

Man what a funny thread! For the fun I'll throw in my two cents:

1) 100%: Yep for a mountain bike it doesn't make a lot of difference... Except that if you have a 44T front chain ring and a 34T rear cassette then the SGS version (long cage) may be the right choice. A 42T front and 32T rear (more common) could be spect'ed with the SG version (medium cage). All mountain bike Ds handle up to 34T

2) Road bikes don't have short/med or long they only have double or triple combos. All road bike Ds are specked for 27T (well 9-speed ones that is). A road bike triple D can work on a double but a double D will not work on a triple drivetrain (it cannot "wrap" enough chain.

3) I've used a XTR mountain bike D on a road bike with a double setup to get a 39x32 low gear. It doesn't matter which model you use the SGS or SG but because the total difference in chain-inches is between 39x11 and 53x32 (or34) then the SG will work. If you want to use a 32T or 34T on a road bike triple then you MUST use the SGS because you are now talking about a 30x11 to 53x34.

4) If you put a mountain bike D on your road bike you may need to place a shim between the D and the dropout (a washer)... Some road bikes got thinner dropouts than mountain bikes and this may move the D inward too far to allow the spring to be effective at shifting into the smallest gear.

5) Of course now with the high-side shifting on mountain bike Ds if you use it on a road bike you will have to get use to shifting backwards.... You can still get the 952 XTR stuff...

6) I think there is an S version of the XTR but it must be really limited in wrap capacity... BTW here is a formula explanation for wrap capcacity for determing cage size...

Total Capacity = (BigRing - SmallRing) + (BigCog - Small Cog)
= (44T - 22T) + (34T - 11T)
= (22T) + (23T)
= 45T
sgs (long) = 45T, gs(medium)=33T (as per tech service instructions)

i'm sorry i was talking about he cage issue, medium or long cageStill makes no sense.How you pedal has nothing to do with it.

Man what a funny thread! For the fun I'll throw in my two cents:

1) 100%: Yep for a mountain bike it doesn't make a lot of difference... Except that if you have a 44T front chain ring and a 34T rear cassette then the SGS version (long cage) may be the right choice. A 42T front and 32T rear (more common) could be spect'ed with the SG version (medium cage). All mountain bike Ds handle up to 34T

2) Road bikes don't have short/med or long they only have double or triple combos. All road bike Ds are specked for 27T (well 9-speed ones that is). A road bike triple D can work on a double but a double D will not work on a triple drivetrain (it cannot "wrap" enough chain.

3) I've used a XTR mountain bike D on a road bike with a double setup to get a 39x32 low gear. It doesn't matter which model you use the SGS or SG but because the total difference in chain-inches is between 39x11 and 53x32 (or34) then the SG will work. If you want to use a 32T or 34T on a road bike triple then you MUST use the SGS because you are now talking about a 30x11 to 53x34.

4) If you put a mountain bike D on your road bike you may need to place a shim between the D and the dropout (a washer)... Some road bikes got thinner dropouts than mountain bikes and this may move the D inward too far to allow the spring to be effective at shifting into the smallest gear.

5) Of course now with the high-side shifting on mountain bike Ds if you use it on a road bike you will have to get use to shifting backwards.... You can still get the 952 XTR stuff...

6) I think there is an S version of the XTR but it must be really limited in wrap capacity... BTW here is a formula explanation for wrap capcacity for determing cage size...

Total Capacity = (BigRing - SmallRing) + (BigCog - Small Cog)
= (44T - 22T) + (34T - 11T)
= (22T) + (23T)
= 45T
sgs (long) = 45T, gs(medium)=33T (as per tech service instructions)1) You don't have a very clear concept of the difference between large cog capacity and chain reap capacity. It's been explained several times. why is the concept so difficult? Your 42 with a 11x32 casette is 41 teeth of wrap.That is long cage territory. 2) road bikes do have s,m and long cage derailers. They also have 29t large cogs. At least campy did the last time I checked. A SC with a triple will certainly wrap enough chain,depending on the chainring and cog spread.I have a SC DA 8 speed that wraps everything on a 52/39/30 and a 13x23 casette. I'm exceeding spec wrp capacity and it still wraps it all. 5) there are plenty of MTB RD that are not low normal...6) Shimano only list 2 cage lengths for the XTR.

I tried to sum it all up but at the end, I actually answered the question It didn't matter.

Not only was I incredibly rusty in this, but I also had my mind on more important things than a drive train.

I actually answered the question It didn't matter.

Not only was I incredibly rusty in this, but I also had my mind on more important things than a drive train.It does matter. Bonus points for a creative excuse. :o

It does matter. Bonus points for a creative excuse. :o Would you not be thinking straight if you found out someone close to you isn't going to be around too much longer?

1) You don't have a very clear concept of the difference between large cog capacity and chain reap capacity. It's been explained several times. why is the concept so difficult? Your 42 with a 11x32 casette is 41 teeth of wrap.That is long cage territory.

Errors are possible... Use the equation provided please.

I think my concept is clear. If it were not then my chain would be getting stuck when I shifted into big-ring-big-casette or the chain would be rubbing the cage in small-small. Or the B-adjust would be hosed.



2) road bikes do have s,m and long cage derailers. They also have 29t large cogs. At least campy did the last time I checked. A SC with a triple will certainly wrap enough chain,depending on the chainring and cog spread.I have a SC DA 8 speed that wraps everything on a 52/39/30 and a 13x23 casette. I'm exceeding spec wrp capacity and it still wraps it all.

Assumed Shimano first off... And common 8-9 speed and that is rare these days to find anything other than the stock shop stuff... Sure Suntour made stuff like that but thread did not say "my 1985 mountain bike"



5) there are plenty of MTB RD that are not low normal...

Yes this is true. But the comment was about trying to find an XTR rear D that was low-normal in a world where Shimano limits your choices (mail order shops only sell latest Shimano stuff these days... Try getting 9-speed Dura-Ace non-triple stuff instead of 10-speed DA stuff).




6) Shimano only list 2 cage lengths for the XTR.

Yep I wasn't sure about that. I thougth I'd found an S version at one time but perhaps that was 8-speed or 7-speed stuff.