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Ways of limiting a 9sp derailleur for a 6sp cassette

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csermonet

Monkey
Mar 5, 2010
942
127
I have an x9 9sp rear derailleur and just built a 6sp cassette and am having difficulty limiting the rear derailleur. I bought a longer limit screw and installed it in place of the low limit screw. When fully turned in to keep it from shifting into 3rd gear(which is nonexistant) it binds on part of the knuckle and wont let the derailleur shift up at all. From the looks of it, it looks near impossible to make an x9 work with a 6sp cassette. Am i going about it the wrong way? Am i replacing the wrong limit screw? Suggestions are welcome!
 
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- seb

- seb

Turbo Monkey
Apr 10, 2002
2,924
1
UK
I can't offer any help with sram, but in case it's useful to you or anyone else, I can tell you that with a longer limit screw I've been able to adjust my Dura-Ace 7800 mech all the way down to the 5-speed that I'm currently running.
 
Freeridin'

Freeridin'

Monkey
Oct 23, 2006
316
2
Colorado
Space your cassette inward one gear width. Dial in your high limit and dial out your low limit. Should be enough to stop the binding.

Or grind down where the screw hits...presumably the tab where the original limit screw sits.
 
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- seb

- seb

Turbo Monkey
Apr 10, 2002
2,924
1
UK
Freeridin' said:
Space your cassette inward one gear width. Dial in your high limit and dial out your low limit. Should be enough to stop the binding.
Click to expand...
Not as easy as it sounds, as most people want to run an 11t cog, and they sit on the end of your freehub unless you do some extensive dremelling. You'll also need to ensure that the spacer you use has an outer diameter small enough that it won't foul the chain when on the smallest cog.
 
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csermonet

Monkey
Mar 5, 2010
942
127
Im using a cheap shimano cassette, same one ive had for a while now. The cassette is a bunch of individual cogs with a spacer between each one. the whole assembly is held together by a screw and when you back it out, you can remove, replace, do whatever you want with each individual cog. I took the 3 low gears out and replaced them with extra cassette spacers i got at my lbs. Not sure if my description sounds like it, but it was a very easy process. almost free to do.

as far as the limit screw binding on the "knuckle", maybe i used the wrong word. when i screw the limit screw all the way in, it gets caught on the side of the tab that the original limit screw came in contact with. If i dremel the tab down, it looks as if the "knuckle" or "parallelogram" or whatever you want to call it, will still come in contact with the limit screw much too soon and keep it from shifting all the way up. I might try spacing it in one gear width
 
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csermonet

Monkey
Mar 5, 2010
942
127
image.jpgimage.jpg

The first pic you can kind of see how I made it. The 2nd one shows where the limit screw is giving me trouble
 
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Bill in Houston

Chimp
Jan 4, 2013
97
0
csermonet said:
Im using a cheap shimano cassette, same one ive had for a while now. The cassette is a bunch of individual cogs with a spacer between each one. the whole assembly is held together by a screw and when you back it out, you can remove, replace, do whatever you want with each individual cog.
Click to expand...
figure out where the derailleur DOES want to shift to, and put the cogs there.
 
C

csermonet

Monkey
Mar 5, 2010
942
127
I think if I spaced it back one width it might work, problem is my last gear is 11t. Any other solution?
 
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C

csermonet

Monkey
Mar 5, 2010
942
127
Isn't the point of it to keep the derailleur tracking as close to the cassette as possible without touching or affecting shifting?
 
no skid marks

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
How weird. I just deleted my three year old or more photo yesterday of my set up with an XO mech.
Yeah forget the limit screws, they fowl on the mech when it's going to the other extreme.
You make a spacer to stop the cable from being able to pull mech up, So a spacer between where the cable outer stops, and cable inner ends. So you can't shift that far. Maybe even a pipe on cable might work. It's a fiddly job. But can be done. I used a modified eraser zip tied on. It wasn't perfect, and if you pushed hard on shifter button it'd shift of mech. But you could feel it unless shifting in anger. Wood might be easiest to work with. Hope that all made sense.
There might be somewhere else easier to limit the travel on the parallel plates or something. Just get a gearbox bike, that's what I did.
 
jonKranked

jonKranked

Detective Dookie
Nov 10, 2005
85,981
24,535
media blackout
its to adjust the derailler angle to give it proper clearance, and should be adjusted when in the largest (diameter) gear. since you've changed that, i'd recommend starting with the b-screw before getting the dremel out.
 
no skid marks

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
jonKranked said:
its to adjust the derailler angle to give it proper clearance, and should be adjusted when in the largest (diameter) gear. since you've changed that, i'd recommend starting with the b-screw before getting the dremel out.
Click to expand...
Huh?
He's trying to stop it over shifting off the shorter cassette right?
He just need s to figure a way to mechanically block it like I suggested. No dremeling, accept for some wood maybe. I'm going to bed, I'm tired, I'm probably missing something, probably shoulda read whole thread, but people ramble on so much, oh, there's my irony. Night folks.
 
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Banshee Rider

Turbo Monkey
Jul 31, 2003
1,452
10
I ran this set up in like 2008. If I recall, I ended up running the 12T as my smallest cog and replaced the 11T cog with 2 singlespeed cog spacers. This effectively shifted the entire cassette in enough that the L limit screw wasn't bottoming out on the body and preventing full range of movement. The set up worked well, and was light as well. Then I stopped caring about weight and PITA measures to lose it. I just run normal cassettes now. It's sweet.
 
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JohnnyC

Monkey
Feb 10, 2006
399
1
Rotorua, New Zealand
Fit a bmx cable knarp to the exposed section of cable at the derailleur, shift in to the biggest cog, slide the knarp up and tighten the grub screw. It won't be able to pull the cable through any further if you tried to shift
 
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csermonet

Monkey
Mar 5, 2010
942
127
No skid marks and johnnyc ---

That's the method I needed to know. Will commence limit screw removal and find something to clamp on the cable. Very simple wonder why it's not more known? Thanks for the tip!
 
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csermonet

Monkey
Mar 5, 2010
942
127
I used the eraser with a zip tie, it works with enough stopping force that downshifting too far shouldn't be much of a problem. Albeit a bit crude. Never heard of a bmx knarp that Johnny suggested. I googled it and just had the local shop that stocks bmx bikes order a pair, since they don't keep them in stock apparently.

Oh and johnkranked, my b limit screw is backed out all the way so the derailleur is already tracking as close as possible.

Banshee rider, what made you go back to normal? I'm not running 1st, 2nd, and 3rd because I don't use them. If coming into a hard braking section and 4th is the lowest I need, I figured it would be much easier to shift to 4th and not into too low of a gear. That was the main draw for me, so being able to limit the derailleur or shifter pull was crucial. Weight savings is just an added benefit, albeit a very small savings. If i werre to list pros/cons of it, the cool/trick/custom factor is higher up on the pro list than the weight savings. Can't really think of any cons but I haven't ridden with it yet, so I'm curious why you went back.
 
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csermonet

Monkey
Mar 5, 2010
942
127
I have an electrical fitting kit, and in it I found a suitable electrical fitting that the shift cable could slide through. It's used for a ground wire I believe, or a small positive/negative stud, it has a hole where you can put a small bolt/screw through it to mount it to your ground or power source, and a barrel where you can put a small wire through and clamp it. I snipped the bolt hole off with some snips and slid the shifter cable through the barrel and clamped it with the proper wire stripper and clamping tool. Works much better than the eraser, with no slippage at all. Still am going to pick up the knarps at the end of the week, but this is a solid option for someone who needs a quick and easy solution.
 
Dogboy

Dogboy

Turbo Monkey
Apr 12, 2004
3,209
584
Durham, NC
csermonet said:
Can't really think of any cons but I haven't ridden with it yet, so I'm curious why you went back.
Click to expand...
I would consider the distinct possibility that you push the eraser out of the way and overshift a con. Also, the knarp will bite into your shift wire and possibly compromise it. That too would be a con. But, it may turn out that either option works great and you won't have any issues. Can't see the appeal personally.
 
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csermonet

Monkey
Mar 5, 2010
942
127
Dogboy - I wasn't satisfied with the eraser, couldn't get it as secure as I'd like. See above picture. The fitting I used could possibly damage it, but if you use the correct tool to clamp it and don't use too much or too little force, the cable should and won't shear. And seeing as knarps are designed for the specific task at hand, if installed properly I don't see how it could cause damage or fail. Your skepticism is welcome though. Just curious why you can't see the appeal, do you have a dedicated DH bike that you do not pedal up hill at all? Granted I am no World Cup racer, the appeal is great enough that many of the top guys do this same thing and it is no secret. This isn't exactly a mod that only a World Cup racer could benefit from though, unlike suspension valving and things of that nature.
 
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csermonet

Monkey
Mar 5, 2010
942
127
fred.r said:
Every cable on a bike gets clamped down on to anchor it.
Click to expand...
There's always going to be some one to rain on another's parade :p I've seen cruder attempts at clamping cables on Walmart bike brakes and derailleurs, knarps and even my ghetto engineering electrical fitting will work just fine.
 
MinorThreat

MinorThreat

Turbo Monkey
Nov 15, 2005
1,630
41
Nine Mile Falls, WA
Maybe I am missing something or maybe I just did not read thoroughly enough - - but isn't it possible to just lengthen you cable to where, when your shifter is downshifted to 1, you've only downshifted the cassette to 4? That should give you positions 4-9. If you click an extra upshift, you get a little extra cable slack to remember to take back up, but that's it. Right?
 
C

csermonet

Monkey
Mar 5, 2010
942
127
MinorThreat said:
Maybe I am missing something or maybe I just did not read thoroughly enough - - but isn't it possible to just lengthen you cable to where, when your shifter is downshifted to 1, you've only downshifted the cassette to 4? That should give you positions 4-9. If you click an extra upshift, you get a little extra cable slack to remember to take back up, but that's it. Right?
Click to expand...
I tried that, I couldn't get the shifting to work properly. With the cable stop method, I'm still using the proper indexing and won't over-shift or under-shift , and won't damage anything but maybe a $2 shifter cable
 
- seb

- seb

Turbo Monkey
Apr 10, 2002
2,924
1
UK
You could also try a rigid sleeve over the exposed bit of cable, carefully trimmed through trial and error to exactly the right length.. Wouldn't need to clamp it to the cable, it'd just sit there loose until you reached the biggest cog.
 
no skid marks

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
The blue sleeve pictured looks good, so does the carp, not that I know what it is, guessing just a grub screw type set up the squashes onto the cable. Lots of things you could use for this.
Using the single speed sprocket and 12 tooth cassette is a good idea if you need it for good chain line.
I was doing the mech limiting things when running a 5 or 6 speed cassette on a single speed hub.
 
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csermonet

Monkey
Mar 5, 2010
942
127
The knarp is basically a barrel that the cable can slide through with a set screw that pinches the cable. Yeah when someone told me I could limit the cable I knew it would be relatively easy to ghetto engineer a temporary solution. Thanks for all the advice everyone
 
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