[SDminitrucker]

I have read through all old threads regarding the shimano 105 rear derailer on downhill bikes. Here are my questions.

1. If i get the shimano 105 rear derailer, do i need to get a road cassette in rear also?



2. Will it shift between the 11-34 rear gears i currently have.


3. DO you guys have a bettter suggestions for replacing my beaten to **** rear XT derailer. I want one that tucks up and is strong.



Thanks for the help,
GIanni

 

[mobius]

No, yes, SRAM? or XT mid cage.

 

[ChrisRobin]

1) No, you don't need a road cassette in back...but the max Shimano will tell you to run is 28t. You can get away with 30.

2) I don't know if it'll shift to your 34T cog...install it and try in a bike stand. If it does shift, it'll be mighty tight!!!

3) 105 derailleurs aren't the strongest around...no derailleur is bombproof anyway.

I think you can get mid-length cage 105 derailleur which are meant for road bikes with 3 chainrings in front.

 

[SDminitrucker]

I'm only running two chainrings in the front.

Do you guys have any other rear derailers to suggests that are shimanos? Since the rest of my components are shimano.

 

[mobius]

XT Mid cage.

I ran a 105 short cage on a 32T rear and 36Front and it worked. I think DßR used it with a 34T rear and it was fine but tight.

 

[DßR]

if you have 2 chainrings in front and a 11-34 it most likely won't be able to take up the chain slack in the small-small combos. You should stay out of those anyway though, unless you're bike-retarded. M is right, I ran a 105 shortcage with a 22-36 and an 11-34 and it could hit all the gears but you couldn't really do small-small combos, like I said.

Try an XT mid-cage or something if you want to use the "useless" combos, it works fine.

 

[MikeD]

if you have 2 chainrings in front and a 11-34 it most likely won't be able to take up the chain slack in the small-small combos. You should stay out of those anyway though, unless you're bike-retarded. M is right, I ran a 105 shortcage with a 22-36 and an 11-34 and it could hit all the gears but you couldn't really do small-small combos, like I said.

Try an XT mid-cage or something if you want to use the "useless" combos, it works fine.

Yep. The cage won't be able to handle your gear spread, and might not handle the 34t cog, either. I ran ss-cage roadie derailleurs on a 36/22 11-30 combo, though.

MD

 

[SDminitrucker]

Yea i'm runnign 11-34 and 22/38 up front and i rarely go into the small gear combos. I guess i'll give the 105 a try. With that short cage will i have to run a longer chain?

 

[MikeD]

Yea i'm runnign 11-34 and 22/38 up front and i rarely go into the small gear combos. I guess i'll give the 105 a try. With that short cage will i have to run a longer chain?

Shorter chain, actually.

When you set it up, set the chain length for your big-big ring/cog combo. Then, fidn out at what gear combos the derailleur returns completely to its rest position with the chain entirely slack. Don't ride in those combos, obviously.

I don't like setting things up like this, because you're bound to shift into the wrong combos at some semi-critical time when you're hallucenating from fatigue...

MD

 

[seismic]

I run a Ultra Shortcage Ultegra Rear der. (shorter arm than normal road der) and an 11-34 casset...NEVER any problems at all !!!!!!!!!!!!! And I like it a lot better than my old XT !!

 

[ChrisRobin]

The XT short cage is probably one of the best choices.

 

[SDminitrucker]

FOr the price i'd pay for the ultegra i'd rather get an xt. But i like the 105 cuz its cheaper, and chances are sicne i'm still leanring to ride smoother i'mg onna bash the **** out of it again, so a cheaper derailer would be the better choice

 

[seismic]

The spring in the Ultegra is much firmer than the XT !! I think the Ultegra is WAY better than an XT...IMO !

 

[MikeD]

For MTB use, though, I think the 105 is just as good as an Ultegra...the Ultegra has better longevity on a road bike, but given the abuse it'll take on a DH bike, I'm sure the lifespan is the same, and the operation is identical within that shorter lifespan.

MD

 

[seismic]

Well, - coming from the road to Dh I would say that Ultegra and DA shift somewhat better than a 105...but that is just my feeling maybe

 

[SDminitrucker]

i agree that the ultegra and xt would be better choices, but i am looking for a small cage derailer that tucks out of the way, and also fits a freshman college students budget, espeically when they are picking up a Super T in the next few weeks.

 

[ride]

buy a 105. They work good enough. they're solid, short cage, and cheap.

 

[Bacardi]

I beat a 105 derailler for about 6 months of rocky trails, and a couple of weekend trips to Northstar.

Put something squishy (piece of tube folded over, furniture foot pad) on the bottom of the chainstay where the derailler would hit when fully extended forward. This helps extend its life some.

 

[lanman]

105's are very nice for DH/all other crap riding, I have been using one for a year. It can take a beating cuz it's tucked up there. I used an Ultegra cassette and I think the highest cog is at 28 or so. I'm going to a Sram X-9 mid cage which is a short cage for a wider spread and I have heard nothing but good reviews for SRAM stuff, it looks very well made

 

[dirtyamerican]

I through on an old 105 onto my Scream, with a single ring up front and 11-34(?) on back, works great also.

 

[SDminitrucker]

A local shop has the 105 shortcage for 35 ish bucks and i think i'm gonna go pick it up tomorrow. Its cheaper some places online by about 10 bucks but they are all backordered, and they i'd have eto pay shipping. SO 35 bucks seems reasonable. I'll let you know how it turns out, especially with my new e.13 DRS chain guide i put on today.

 

[SDminitrucker]

Well guys i picked up the derailer today for 36 bucks and threw it on. Its not completley tuned yet but i am very happy with it and my new e.13 DRS. The only thing about the 105 is that i can only have 7 out of 9 of my rear gears cuz the pull isnt long enough. Could i have done something wrong? Anyway i cant wait to get out on some trails to see how it holds up

 

[MikeD]

Like we said, you won't have a full gear spread with this derailleur and your chainring combo, esp. combined with such a wide-range cassette.

Set your chain length (current one may be too short now) so that your derailleur is stretched forward near *but not at* its maximum reach in the big/big gear combos. Then you should have full use of your big chainring, and the granny gear should still be usable in the upper cogs. If you use the granny with the lower cogs, there will be too much chain slack. Not an ideal setup, like we mentioned earlier.

MD

 

[DßR]

The only thing about the 105 is that i can only have 7 out of 9 of my rear gears cuz the pull isnt long enough.

Would you care to be more specific? I haven't the foggiest clue what you're saying, and I do this for a living.....

 

[Ciaran]

I run a single 34t chainring up front and an 11-34 in the back and can shift easily into all my gears. When using multiple gears up front I usually shorten the chain a lot. While in the big ring you can't shift into the biggest 2 or 3 cogs. These ratios are duplicated elswhere in your gearing. You just have to have the presence of mind to know where your chain is.

 

[MikeD]

When using multiple gears up front I usually shorten the chain a lot. While in the big ring you can't shift into the biggest 2 or 3 cogs.

See, I don't like running it that way...you could potentially tweak the derailleur the hanger (or even rip it off, but that'd take a BIG effort...) if you tried hard to shift into those cogs when your 'presence of mind' was elsewhere...if you set the chain long enough to accomodate that big-big combo, you're eliminating that risk. Worst that'll happen now is your chain will be too slack in the granny gear on the lower half of the cogset.

 

[OGRipper]

When you say the "pull isn't long enough" it's not clear what you mean. Hopefully you didn't get an old 7 or 8 speed derailleur, because in that case the throw might not be wide enough (assuming you've got a 9 speed cassette and shifter.

If it's not shifting onto the biggest couple of rear cogs but you know it's the right derailleur, try turning in the pivot screw. Sometimes you need to tighten it all the way to get the upper pulley to clear the cog, if it's not right the upper pulley will just smack into the cogs.

I think we're all assuming you know how to adjust the upper and lower limit screws. If not, ask what I'm talking about.

Edit: I completely agree with Mike D on chain length, if it's too short you WILL at some point shift into the big-big combo and jam your chain. I've got my own approach though, to me, with a double, the "big-big" combo is really just like using "middle-big" on a triple, which should be available, whereas "granny-little" is pretty much useless.

 

[MikeD]

I'm guessing he means the derailleur is stretched forward to its max and won't allow him to shift to a bigger cog (ie chain's too short). Anyone else care to place a bet?

 

[OGRipper]

Mike D is prolly correct, especially when you add in the fact that the DRS will take up a little more chain. But when I first read that the derailleur was $10 less than any mail order my first thought was "Uh-oh, it's 7spd NOS."

 

[davetrump]

the only advantage of a road deraileur is the short cage... the biggest problem is that road derailleurs crap out real easy on a dh bike.... and almost all good road deraileurs are 10 speed now so they will no longer work.

for the past few seasons i have had the best luck running mtn deraileur (lx or xt, non rapidrise) with the cages removed and replaced with shorter road cages.

try your local shop o see if they have any junked road deraileurs lying around that hey use for parts and take the cage off it (it is real easy to do on shimano's)

i have had the same cage for two seasons and just buy whatever deraileur i can find and keep reusing the road cage with it.

all shimano road and mountain cages are interchangeable as long as they re not meant for 10 speed systems (except some xtr and dura ace models depending on year)....

 

[buildyourown]

the only advantage of a road deraileur is the short cage... the biggest problem is that road derailleurs crap out real easy on a dh bike.... and almost all good road deraileurs are 10 speed now so they will no longer work.

Huh? They hold up fine. At least as well as anything else I've tried. It doesn't really matter if the der was made for 10, 9, or 8 spds. They will all work. If you really want to get picky, you can still find new 8 and 9 spd ultegra and DA.

 

[SDminitrucker]

Would you care to be more specific? I haven't the foggiest clue what you're saying, and I do this for a living.....

Sorry were all not mechanics. When i was explaining the pull, i was referring to the cable pulling the derailer, which then shifts it. What it is doing now is not shifting to my two biggest cogs.

When you say the "pull isn't long enough" it's not clear what you mean. Hopefully you didn't get an old 7 or 8 speed derailleur, because in that case the throw might not be wide enough (assuming you've got a 9 speed cassette and shifter.

Thanks, i'll give that a try. Like i said i just threw it on, and barely messed with it. Maybe tonight after i finish my chem and calc i'll be able to play wiht it.

 

[SDminitrucker]

K i ****ed with it some more, and now it shifts to all 9 rear gears. Thanks for the help guys.

 

[SDminitrucker]

K another update. after doing some stair gaps drops and rdiing down countless stairs i couldnt be happier with this derailer for what i paid for it. ONly thing pissing me off now is my ****ed up sholder after my crash on saturday. Thanks again for the help, its nice to see people on a forum actually help and not flame.