I need some Derailleur advice.

PB Forum :: Mechanics' Lounge
I need some Derailleur advice.
Author Message
flag ajax-ripper
Posted: Jan 18, 2009 at 20:07 Quote
davemud wrote:
odin333 wrote:
trekliuid10 wrote:


Try it some time and then let us all know how it worked out for youBook

if your running a shimano shifter on an SRAM derailleur it would jump two gears every one shift. opposite for SRAM shifter on shimano derailleur, one click would put the derailleur inbetween gears, two clicks would change it one gear. its not like it implodes on itself, it just doesn't work out.

Its true Shimano doesn't make a Sram compatible shifter. Sram does as I mentioned before make Shimano compatible shifters:

MRX Comp Grip shift
TRX Trigger
Attack Gripshift
Attack Trigger
Rocket Trigger

As well as some comfort/city bike dual shifters.
and any friction shifter and you can run either shifter brand on a suntour duro derailleur
as seen here

it's a shame they got discontinued. they were the ultamate back up. you buy 3 for 60 bucks bring them to whistler if a buddy blows a r/d you pop that one on because it doesnt matter what shifter you have.(one side of the bolt is 1:1 the other is 2:1)
flag davemud
Posted: Jan 18, 2009 at 23:24 Quote
The Suntour Duo is a great idea but I wonder how well they work in either mode. Before index shifting Suntour XC Pro was the best MTB component group. Suntour however could not get their index shifting to work as well as Shimano and got wiped off the map by Shimano then Sram.
flag schwimble
Posted: Jan 19, 2009 at 10:19 Quote
why dont you keep things simple, and cheap..er. my suggestion, seen as you seem hell bent on spending money, would be to go with an XT or saint mech in a short cage model. ie a shimano "shadow" mech. these mechs have a direct cable routing, like sram, so theres much less chance of the cable being broken from a stick or bush etc. these obviously have a much lower profile too, so there is less chance of them breaking off rocks etc. plus they dontflop around like other shimano mechs.
flag davemud
Posted: Jan 19, 2009 at 13:57 Quote
I chuckle when I see things like "don't flop around like other shimano mechs". Since most times its not the derailer itself its the set up, a tripple crank when a double will do and/or the chain is too long and/or stretched and/or the B tension screw is incorrectly set and/or all of the above plus the rider errors listed below.

Far far more common than any of those though is the rider chooses the wrong gear for a rough section. If you don't want the chain slapping around you need to be running in the biggest front ring you can and biggest rear cog combo you can. Doing so takes up most of the slack and reduces how much the chain slaps around.

After gear selection, line selection and riding finess also contribute to how much your chain slaps around. The smoother you ride the less of a thrashing your bike, derailer and chain take.
flag w-e-w
Posted: Jan 19, 2009 at 15:07 Quote
davemud wrote:
I chuckle when I see things like "don't flop around like other shimano mechs". Since most times its not the derailer itself its the set up, a tripple crank when a double will do and/or the chain is too long and/or stretched and/or the B tension screw is incorrectly set and/or all of the above plus the rider errors listed below.

Far far more common than any of those though is the rider chooses the wrong gear for a rough section. If you don't want the chain slapping around you need to be running in the biggest front ring you can and biggest rear cog combo you can. Doing so takes up most of the slack and reduces how much the chain slaps around.

After gear selection, line selection and riding finess also contribute to how much your chain slaps around. The smoother you ride the less of a thrashing your bike, derailer and chain take.

Yeah... all of that and the tiny little detail that traditional Shimano der's pivot at the hanger while Sram are fixed.

I say "traditional" because I understand that the new Shimano "Shadow" der's are also fixed at the hanger, although I haven't checked them out myself. I wonder where they got that brilliant idea??

It's pretty common for traditional Shimano der's to have problems with the cable at the barrel adjuster or with the barrel adjuster itself. It's true that you can mitigate the issue with proper set-up, line selection, and general awesomeness... or you can just eliminate the issue completely with a der. that is fixed at the hanger... like all the top-end DH / FR der's now.
flag schwimble
Posted: Jan 20, 2009 at 8:01 Quote
davemud wrote:
I chuckle when I see things like "don't flop around like other shimano mechs". Since most times its not the derailer itself its the set up, a tripple crank when a double will do and/or the chain is too long and/or stretched and/or the B tension screw is incorrectly set and/or all of the above plus the rider errors listed below.

Far far more common than any of those though is the rider chooses the wrong gear for a rough section. If you don't want the chain slapping around you need to be running in the biggest front ring you can and biggest rear cog combo you can. Doing so takes up most of the slack and reduces how much the chain slaps around.

After gear selection, line selection and riding finess also contribute to how much your chain slaps around. The smoother you ride the less of a thrashing your bike, derailer and chain take.

you miss my point about the flopping around, all other shimano mechs are hinged (yea i know, wrong word) at the hanger. this means the cable, and the outer are being flexed all over the place the bike bumps around, whether its set up correctly. this inturn leads to the chain flopping around more than on the new shadow mechs, or sram mechs. i think it also leads to the outer cable cracking at the barrel adjuster too.
flag davemud
Posted: Jan 20, 2009 at 10:29 Quote
Once again, proper set up, proper gear selection and proper line selection reduce the issue to a non-issue. Pretty much every casing I've ever seen kinked at the back of a traditional derailer was too short and/or worn to the point it needed to be replaced anyway.

The new design improves things by making set up and gear selection more, pardon the expression, idiot proof for inexperienced people and/or less refined riders. Yes I agree it is better but no it is not necessary if you are an experienced mechanic and rider. We got along quite well for over a decade without those features.
flag w-e-w
Posted: Jan 20, 2009 at 10:38 Quote
davemud wrote:
Once again, proper set up, proper gear selection and proper line selection reduce the issue to a non-issue. Pretty much every casing I've ever seen kinked at the back of a traditional derailer was too short and/or worn to the point it needed to be replaced anyway.

The new design improves things by making set up and gear selection more, pardon the expression, idiot proof for inexperienced people and/or less refined riders. Yes I agree it is better but no it is not necessary if you are an experienced mechanic and rider. We got along quite well for over a decade without those features.

We got along just fine with cantis and fully rigid too, don't see too many of those set-ups at the races though do we? Wake up man... you're talking down to everyone here and missing the entire point.... You state the obvious like you're schooling everyone, yet you should be listening and not preaching. From the way you come off here, I wouldn't let you go near my bike with a wrench. Coincidentally, even the latest issue of Dirt Mag says that removing that pivot is the BEST thing Shimano has EVER done... but i guess all the guys at Dirt just need a Wrenching and Riding lesson from you... along with all of us here trying to point out the obvious to you.

I feel like a sucker for getting into an internet debate, but I can only listen to so much crap.
flag davemud
Posted: Jan 20, 2009 at 16:48 Quote
Funny you should make those comments.

I was just at Shimano's 2009 tech seminar today and talked to their head tech about rear derailer design including the reasons for the new Shimano design why they are different and how the Sram and Shimano derailers differ in function from each other because of their design.

Yes I do pass on my knowledge and try to inform people about various aspects of bicycle design and set up. There is a lot of misinformation and misunderstanding about bikes on this site and in this thread and I like to try and help people sort out the good info from the bad.

I'm not forcing you or anyone else to read it though.
flag w-e-w
Posted: Jan 21, 2009 at 9:23 Quote
davemud wrote:
Funny you should make those comments.

passive aggressive much?

davemud wrote:
I was just at Shimano's 2009 tech seminar today and talked to their head tech about rear derailer design including the reasons for the new Shimano design why they are different and how the Sram and Shimano derailers differ in function from each other because of their design.

...and? anything relevant to add? Does a der. with a pivot at the hanger flop around and stress the cable more than one that is fixed or not? Or was I just supposed to be impressed? Fab

davemud wrote:
Yes I do pass on my knowledge and try to inform people about various aspects of bicycle design and set up. There is a lot of misinformation and misunderstanding about bikes on this site and in this thread and I like to try and help people sort out the good info from the bad.

My bad man.. thanks for gracing these pages with your knowledge; we are all better for it. Here I thought you were bring condescending and narcacistic, but you're just trying to help out us common folk. I hope to meet you on the trail or in the shop some day so that you can further impart your insights on line selection and bike set-up. Clearly, I have much to learn.

davemud wrote:
I'm not forcing you or anyone else to read it though.

...not being forced to read what you write is like not being forced to smell a guy with bad BO... there's no real way to avoid it, and it's always offensive.

I'm done.. my apologies to everyone for stooping so low... Salute
flag JokerMachine
Posted: Jan 21, 2009 at 9:32 Quote
PinkBike needs an "eating popcorn" emoticon... this is better than a Blockbuster movie.
flag davemud
Posted: Jan 21, 2009 at 9:36 Quote
Since my handle and photo are at the top right of all my posts why not just ignore my posts when you see them? Then you don't have to be offended and those who find the info useful can receive it and the thread doesn't have to be degraded by nonsense like this.

Its a big forum, we don't all have to agree but it would be nice if we could all show each other a little respect.
flag JokerMachine
Posted: Jan 21, 2009 at 9:40 Quote
I will add this, after 2 months of using my bike with a Deore LX derailleur and the proper amount of cable housing, it was kinked at the barrel adjuster.

Oh yeah, and then the barrel adjuster snapped off, but I think that was my fault.
flag davemud
Posted: Jan 21, 2009 at 10:11 Quote
If the ferrel is one of their black plastic ones those are crap and should be replaced with a metal one. Cables and casings are critical to the precision of the system and need to be changed far more often than people think.

I did talk with the rep abut the bouncing around of the rear derailer. He mentioned what I was getting at when with the old hardtails. If you rode or ride a hardtail you do learn to use the biggest chainring and cog combo you can to take up the most chain slack and increase the spring tension in the rear derailer.

The original Shimano design does hit the chainstay on horst link bikes due to where the pivot is. There are a variety of reasons the shadow derailer was developed but it is not a copy of Srams design. The shadow is different in function from both Sram and Shimanos own design.

The original shimano derailer must pivot so it can follow the cassette and maintain a gap of about 1 mm between the cog and upper pulley wheel. The Sram is different and gets farther away from the cog as the cog gets smaller in size.

He also mentioned a video on line comparing the Sram and Shimano derailers movement. Both move but the Shimano derailer's motion maintains chain tension where as the chain tension varies with the motion of the Sram.

My comments on choosing proper line to reduce chain slap come from 30 years of riding experience, watching elite racers at downhill and XC events and reading their training tips in magazines. Pretty much all of them mention riding as smooth as possible to conserve energy, momentum and reduce punishment like chain slap to the bike.

This may seem obvious to some but we mechanics see a lot of unnecessary damage and wear and tear on bikes due to less than ideal riding practices.
flag nothingbetter
Posted: Jan 21, 2009 at 10:35 Quote
JokerMachine wrote:
PinkBike needs an "eating popcorn" emoticon... this is better than a Blockbuster movie.

BAHAHAHA! Comment of the day!

 


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