tandemnh

I just bought a 2004 C'dale R2000 Triple (never riden) and I have replaced the cassette with a 12x30. Per their add and Sheldon Brown, "This cassette will index with any Shimano-type 9-speed shifter and any rear derailer."

Well I installed it tonight and spun it while in the bike stand. Seems to be a bit rough at the rear derailier. Do I need a long arm derailier or do I need to play around witht he adjustment screw?

I did not buy their recommendation of a chain, "We recommend the SRAM PC-951 chain for use with this cassette." Would this chain be better than the original chain that came with the bike (remember no miles)?

I ride a lot of hills so I am determine to try riding this year with the option of a 30x30. I know a bit over the top, but that's my goal to get over the top faster and with out nearly the effort.

So what should I be trying?

motobecane69

what RD is on there now would help us for starters but at 30 teeth, yes you probably should be using a long cage deraileur. try turning the Bscrew all the way in for starters.

tandemnh

Yes that might hav helped. It has an Ultegra drive train all parts.

Could it be that maybe a longer chain would do the trick? I just thought since it has a 12/23 and I've bumped it up to a 12/30, maybe to start with a few more links would be a wise first step?

motobecane69

you may need chain links but if you put it on the small chainring upfront you'll have plenty of chain to test if it will shift onto that big cog in the back. If it does, thats half the battle. you have to be careful trying to shift it to the big/big because you can break the deraileur off and lodge it in your wheels. I know your not supposed to run it in the big big combo but if you ever let someone borrow your bike who is less experienced or if you simply accidentally do it, you don't want to mangle your bike.

There is a good chance an ultegra GS RD will solve your problems. Where did you get the bike from? if it was from a shop, they might swap the RD for you. in the short term you could put on any shimano MTB RD. I had an acera on the back of my bike for awhile while i hunted down an ultegra GS

desertdork

If it's a stock triple drivetrain, then it should already have a long-cage Ultegra RD (GS) on it. While he might be able to get the derailleur to handle the 30t cog, he's still exceeding the chainwrap capacity by several teeth. A long-cage mtb RD (SGS) is the most workable solution; however, switching out the inner chainring for a 28 or 26 would have been much cheaper in the long run.

tandemnh

I'll plan to research both options today. Derailier and inner chain ring.

JonathanGennick 

You almost certainly need a longer chain, unless the original was overly long to begin with. To size a chain, I loop the chain over the big ring and big cog, without going through the derailers. Then I add a full link (inner + outer) to be safe. That gives the shortest reasonable chain length.

You can do some simple math to check whether your rear derailler has the right cage length:

(large cog teeth + large ring teeth) - (small cog teeth + small ring teeth) = important number

Then look on shimano.com for the maximum tooth count that your rear derailleur can take up. Make sure the derailleur can handle the number of teeth you computed using the above math. What a derailler can handle depends upon cage size.

SmallieBiggs

This is a common mistake - long cage road derailleurs have the same max. cog size as short cage. THerefore, the solution you propose will make no difference.

mbusha

There are two separate issues here -- Max cog size and chain wrap. I think the OPs setup is pushing the limits on both.

Assuming a 53-39-30 crank gives a chain wrap of (53-30) + (30-12) = 41. I think the current specifications for the Ultegra GS rear derailleur are 39teeth, so you're pushing that. While I've not tried it, I'm told you can typically push two teeth beyond the specification here, so there's a possibility the defailleur would work. Another option to help with this problem would be to run a 50 or possibly 52 tooth big chainring (although, I don't know if shimano makes a 50 tooth chainring in 130BCD).

The issue that SmallieBiggs is referring to is a separate problem. The length of the cage just determines how much chain slack the derailleur is able to take up, and has nothing to do with the largest compatible cog size. Shimano lists the max cog size as 28T for both the GS and SS. That being said, I've managed to get an older 105 derailleur that also had a max cogsize of 28T to work with a 32 tooth cog by adjusting the B-screw all the way. Shifting in/out of the biggest cogs wasn't smooth, but for 30T it should work in a pinch.

A better solution, al la motobecane69, would be to go with a MTB derailleur. Something like an XT mid-cage derailleur should do the trick with only a ~30 gram weight penalty over ultegra. I have a similar setup on my touring bike and it works great with my indexed road shifters.

I don't think the exact chain model will make any significant difference, but you will need to make sure to get the length right as JonathanGennik describes. You'll be a 2-4 links short if you up'd the cassette from 23 to 30.

cyclist2000

You increase the large rear cog size by 7 teeth, you will need to add quite a bit of chain for it to work optimally. Also look up your derailluer on shimano techdocs to determine the largest cog size and total capacity.

JonathanGennick 

@mbusha, excellent post. I had forgotten completely about the max cog size issue. Thanks for bringing that to light.

motobecane69

okay guys don't make me post photos my goddamn bike one a 50/34 with a 11/32 and the other a 52/42/32 and an 11/32 with ultegra gs RD. IF you think shimano's chain wrap capacity or max cog spec is a hard and fast number, you've obviously never worked on a bike and shouldn't be providing answers.

I will give you that if the bike did come stock with a triple than it should have come with the gs already in which case, the op probably just needs to add some links. Make sure you can shift it to all the cogs in the granny and the middle ring first Then ascertain the chain size needed by going around the big ring and the big cog and adding one link as previously mentioned.

davidad

Simplest solution would be to replace the silly 30 in the front with a 24. The shifting will take a little more thought, but it works fine. A 24-24 gives the same gear as a 30-30.

motobecane69

i don't know if that would be the simplest, you could definately encounter problems with a 28 tooth differential between your smallest and largest chainrings, FD cage may not work with that.

himespau 

Not that we don't believe you, but pics or it didn't happen. Just sayin'

tandemnh

Some great thoughts and suggestions. As a last resort I will plan to go with the MTB derailier as my C'dale tandem equiped with Ultegra has a Deore XT (maybe XTR, to lazy to run down stairs and check) rear derailier.

Up front the triple is a 52/42/30.

I think I will first look at a new chain and resizing it for the extra length needed.

What is the mechanics behind the different lengths of the arms on a rear derailier? What does the longer length do? Does it have to do with how it centers the chain out back? Does it allow for more slack take up so you can run the longer chain? What exactly does the extra length buy you? That would be very interesting to know.

I would like to see some pics of your drive train set up.

mbusha

(sorry for the long post -- I tend to be verbose at times)

Just as you speculate -- the longer derailleur cage lets it take up more chain slack.

When in the crossed big-big gear combination, there should be no slack in the chain and the derailleur arm should be pointed almost straight from the cogset to the cranks. As you switch to smaller cogs/crankrings, slack is created in the chain, which the derailleur takes up by swinging back to increase the distance between the end of the derailleur cage and the chainring until it rotates ~120 degrees from the original position. Very roughly, the amount of slack the derailleur can take up is proportional to the length of the arc traced out by the end of the cage as it rotates (admittedly, this is a simplified picture, since the relevant measurement is actually the distance from the end of the cage to the bottom of the chainring, but the geometry works out similarly). A longer cage traces out a longer arc, hence a larger chain wrap.

With a 52/30 up front, I definitely don't think the chain wrap will be much of an issue. You're only exceeding the specifications by 1 tooth, and as discussed, there's definitely some slop in the specifications, if for no other reason than that the chain length can only be changed in incriments of two links. This will make it difficult/impossible to get the derailleur at the "optimal" angle for taking up no slack in the big/big combination in every bike, so shimano needs to be conservative by ~2 links when quoting chain wrap capacity. What this does mean, however, is that the derailleur will be more picky with regards to the exact chain length as you approach/exceed the chain wrap specifications.

I tried a quick test last night. Using a Villiger Omnium with a 1056 RD (28T wrap capacity) and 12-26 8-speed cassette, I swapped out the standard double crank (53-39) for a Shimano R700 compact (50-34), and kept the 1056 FD. This upped the chain wrap of the system from 28 (the "official" capacity) to 30 (sort of mimicking the setup motobecane69 has). It worked reasonably well, although a few minor adjustments were needed. The basic problem was that, setting the chain length correct for the big/big combination, the derailleur was just barely able to take up the slack when I shifted to small/small. This was nomainally fine (if for no other reason than I shouldn't really be using this combination), but whenever I went over a mid-sized bump, the chain would bounce up and down a bit and occassionally rub against the upper RD pulley wheel or end of the FD cage (although the latter could just be because I didn't lower the FD). I was able to improve this by playing with the b-stop to create as much tension as possible, although it didn't entirely go away (sorry, didn't take any pictures, but I can try to post some this evening). This problem looks like it would be easily fixed by shortening the chain, but then I don't think it would be long enough for the big-big combination. In order to eliminate one variable, I tried both 8 and 9 speed chains (since my drivetrain is now mixed) to the same result. Have other people had to do any adjustments when they exceed the chain wrap, or does it typically just work without problems? Now I just want to figure out if I can get this to work!

tandemnh

My front rings are actually 52/42/30 so the overall chain wrap is 40, just 1 more than the spec. of 39.

I think what I'll do this evening is to add a couple links (first check the big-big) to determine if the extra links will work. Then buy new chain if this is the fix.

Then if need be spend the money on the derailier, something with a long arm.

motobecane69

You never mentioned EXACTLY what your shifting problem was, just that it was "rough" did you get it to shift through all the cogs in the middle and small rings? Have you confirmed that you have the ultegra GS long cage RD? The only issue that would prevent you from getting it into the largest cog with the Ultegra GS was if you have a short Deraillleur hanger but even then it would probably only be a problem with a 32 tooth RD. Also note that some people change the Jockey wheels on their RD to help with shifting I belive they go to 10T jockey wheels from the 11 T standards but that is probably over thinking this issue.

For those that want a pic here you go 32 tooth cog and ultegra gs

50 tooth big ring and 32 tooth I still need to put a link or 2 into this chain but it shifts and works fine

tandemnh

I can shift through all the gears. The problem is when I'm in the 30x30 there is a rough, somewhat clickin sound as though it is not running clean though the sproket exchange as I pedal. It is as though it may not be lining up straight. I will be trying an adjustment this evening to see if I can fix it with the adjustment screws.

tandemnh

The derailier is standard length. Looks like the one in the picture. is that just the ultegra gs?

tandemnh

I figured out the problem... now who has the fix?

The upper most wheel on the RD that releases the chain to the cassette is not in parallel. The RD wheel is slightly tilted to pick up the chain from the front sproket as the chain naturally comes in at an angle.

The question is, how do you either put distance between the top RD wheel and the cassette 30 sproket or how do out space between the RD sproket and the casstte? If I hold the RD in such a fashion as the two are not in close contact the clicking goes away. and it appears to work fine.

motobecane69

have you turned the b screw in all the way? can you post a picture of it in the state you mention, your description has me confused. to answer your question to me, yes, my RD is the ultegra gs.

If i'm understandingyour description correctly, you need the b screw turned in more so that you sort of push the deraileur away and get more clearance. if the b screw is in all the way, you can try to hunt down a longer screw or even try installing the screw backwards.

tandemnh

I screwd the b screw all the way in and flipped it around, still not getting the clearance. Will stop at the bike shop today and see if I can bet a longer b screw. I'll try to get a picture on this evening.

tandemnh

Great news, the fix is in!

I replaced the "b" screw from an old MTB Deore LX RD and a 10T sproket. That's all it took with a listtle adjustment and I am as good as gold. No click run through the gears great.

Thanks to all for the input. Great that I had the parts around the garage and did not have to drop a c note to replace the RD.

Now to go by that new computer with the money saved!