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Discussion Starter · #1 ·
On a 29"er of course. :D I know several of you on this board run SS hubs with 4 or 5 cogs. What have you found to work well in terms of getting the rear derailleur to mesh with the larger cogs being so much closer to the dropout?

I put a couple ~1mm spacers between the derailleur and hanger, which seemed to help some, but I don't want to put any more on for fear of the derailleur bolt not engaging the hanger adequately. Thoughts/ideas?
 

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Discussion Starter · #4 ·
dustintendo said:
replace the limit screws with longer ones, they use m4 screws, i just did this turning my monocog into a 2(maybe going to 3 when i get spacing figured out) speed
The stock limit screws on the SLX derailleur are actually long enough to limit it to the 4 innermost cogs; I can see where longer ones might be necessary with just 2 or 3 cogs though. I might try a longer B tension screw, but I don't even know if that would do much good with the angle the screw approaches the stop in the larger cogs (it's not even close to making contact at that point).

FWIW, I'm trying to use 21-24-28-34 cogs with (I believe) a short cage SLX derailleur. Would long cage be any better?
 

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Discussion Starter · #6 ·
Jwiffle said:
I wouldn't use washers between the der and hanger.
Why not- you think the derailleur will rip out if the threads aren't fully engaged? The easy solution would be to put a longer bolt on the derailleur and use more washers, but (with Shimano derailleurs at least) it seems to be captured pretty well and not an easy swap.

Maybe use some cassette spacers on the hub behind the cogs.
I'm not sure what you're getting at here; it's not like the cogs are just floating laterally on the cassette body. :confused: I'm doing a trial version on a hub with a full cassette body at the moment, so I do have spacers (i.e. the rest of the cassette) behind the cogs. If it seems like it will shift satisfactorily then I'll be using a wheel with a singlespeed hub that can only fit four cogs total, with no need for spacers behind them.
 

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mnt bike laws of physics
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A longer cage will not make a difference in how the cage moves when you shift...you will be better off using a short cage with the gear spread you are using.

I think you have a great idea in using a longer mounting bolt. I'm sure there is just a retainer holding the bolt on...you should try and take it off and then locate a bolt that is longer and then put washers behind the derailleur as you mentioned. It will be sticking out a little more which could be an issue for catching things and putting more stress on the hanger, but it would be the best option....maybe the only option for the gear range you plan on running to keep the deraileur off of the large cogs that will be so close to the dropouts.
 

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My pictures of a 6 speed setup using Hope Pro II SS hub, Sram X9 medium cage derailleur and a PG990 cassette (11-34). If you use 11-32 you'll have a 5 speed instead.

http://gallery.mtbr.com/showgallery.php/cat/1656

The metal ring between the dropout and derailleur is about 1mm wide.

The setup works perfectly. I love having a strong dishless wheel.

Make sure you replace the low limit screw with an M4 screw.
 

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I used a Shimano Rapid Rise M953 - worked like a charm on the hard tail. Not so much on the dually - but that was more due to the rapid rise than the 5 speed setup.

Anyway - no spacers, no other accomodations. Just cranked down on the limit screw and refined cable tension as required. Pretty clean and efficient on the hard tail.
 

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Why are you using spacers for the mounting bolt?

If you're using a Shimano der. (which it seems you are), at most you'll just need a longer limit screw. I couldn't get the sram to function properly due to the angle of engagement the limit screw makes with the stop. Shimano works fine as long as you're not using the shadow version.
 

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I may be wrong, but what I am hearing from miles e is that the upper derailleur pulley is running into the larger cog as he shifts. Is that right miles e?
If that is the case, he does need a spacer to move the derailleur back enough so that when he shifts the pulley won't swing into the cog since the derailleur was designed to engage into the larger cog at a much farther distance back from what he is proposing it to do.
 

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miles e said:
The stock limit screws on the SLX derailleur are actually long enough to limit it to the 4 innermost cogs; I can see where longer ones might be necessary with just 2 or 3 cogs though. I might try a longer B tension screw, but I don't even know if that would do much good with the angle the screw approaches the stop in the larger cogs (it's not even close to making contact at that point).

FWIW, I'm trying to use 21-24-28-34 cogs with (I believe) a short cage SLX derailleur. Would long cage be any better?
The large size of the cogs is a big part of the issue. I do not have a problem with my 12-32 5-speed after I installed a longer low limit screw (spacing the RD out may have avoided that need). My goal is to retain the gearing range. with more significant ratio changes and increased cog spacing for less fussy indexed shifting. Still fits on a Hope SS hub.

I think the best you can do is to run the B-tension screw in all the way and have the chain as short as possible.
 

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shiggy said:
I think the best you can do is to.... have the chain as short as possible.
Interesting advise. I haven't thought about that, so I checked my 3 rear Derailleurs to see for myself. They all had different results in how much the pulley was lowered when shortening the chain length.

1) Sram X-9 makes a slight difference.
2) XT Shadow makes no difference at all because the cage's pivot and the pulley's center or rotation are concetric.
3) older XTR M952 medium cage (which is the one I plan on using for my SS hub) makes a huge difference when I shortened the chain length.
 

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yogiprophet said:
Interesting advise. I haven't thought about that, so I checked my 3 rear Derailleurs to see for myself. They all had different results in how much the pulley was lowered when shortening the chain length.

1) Sram X-9 makes a slight difference.
2) XTR Shadow makes no difference at all because the cage's pivot and the pulley's center or rotation are concetric.
3) older XTR M952 medium cage (which is the one I plan on using for my SS hub) makes a huge difference when I shortened the chain length.
SRAM RDs are a bad choice for this type of setup.

1. The low limit can not be set properly

2. The jockey (top) pulley is nearly inline with the cage pivot so it relies mainly on the parallelogram to track the cassette. Great for a specific gearing. Terrible if you try something out of the norm,
 

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Discussion Starter · #18 ·
jncarpenter said:
Why are you using spacers for the mounting bolt?
Since I'm effectively moving the cassette outboard (by removing the 5 innermost cogs), I was trying to do the same with the derailleur. It did help too- without them I couldn't even get the chain in the largest cog, with them the derailleur would clear, but was still a bit too close.

I think I'm going to try a 32 tooth big cog, shorter chain, and maybe a non-Shadow derailleur per the suggestion here. Thanks all!
 

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On my 4/5 speed setups I don't try running the cogs all the way outboard on the hub. I usually have the biggest cog (32t in my case) just 1-2 spacers inboard from the "normal" position, and use more spacers than that on the outboard side. Any further outboard than that, and I usually end up with the same problem of the pulley dragging on the big cog. I do crank the B-screw in all the way and try to keep the chain as short as possible, but (at least with Shimano XT derailers) I haven't had to resort to replacing the stock B-screw or using spacers on the derailer mount itself. This probably doesn't give a perfect chainline, but I'm usually using the middle, not outer, ring anyway so the chainline is still decent in the higher gears where efficiency is more important. As it is, this system shifts flawlessly and crisply with no interference on both my Lev and my commuter rig.

I would echo the comments about SRAM derailers. Not going to work well in this application.
 

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This is a lot of great information.

I am planning on doing a similar setup on my Monocog Flight. It seems that the limit is 3 gears (I wonder if I could switch the free body?). I have a short Tiagra RD. Where can I find the m4 screws?
 
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