Rear Derailleur is Hitting Spokes, HELP PLEASE

[Triskeliongirl]

OK. Last time I wanted to change a cog set, I purchased the tools from my LBS, and in showing me how to use the tools they changed it for me. Today, I did it myslef for the very first time. I think I did it correctly, but here is the problem. The bike is my husband's. He was running a 53/39 in front with a 12/23 casette in back and what looks to be a very short cage rear derailleur (all durace 9). The new casette we ordered is 12/25. First DH replaced his chain before going out of town. By mistake he made it a link shorter than the old chain. The new casette arrived today. It seemd to install smoothly (yey, my first time!), and I got the rear dearailleur adjusted so it would shift nicely (mostly all I fiddled with was the barell adjustor on the tension, or whatever that knob is that lets you make fine adjustments in the tension), but I noticed a problem when in the small front ring and large rear ring. The part of the derailleur that hangs down in back hits the spokes of the wheel. Is this because a 25 tooth cog is too large for a short cage rear derailleur, or because the chain is too short? If its the derailleur, can I even find a 9 spd durace rear derailleur anymore, and if so which one do I need (or maybe easier he could go back to a 12-23 casette, he was OK with it but on a very hilly ride last weekend one of the racer boys commented he'd be better off with a 12-25 and since it was worn and needed replacing he decided to try it. Please help, as I am supposed to have the bike ready for us to go on a ride early saturday, and he is getting back from his trip tomorrow nite.

[velogirl]

Sounds like you need a longer chain. Be careful when in the big/big combo (not recommended anyways because you're cross-chaining, but it happens, right?). Your rear derailleur could get sucked up into your cassette.

Not that I know from personal experience or anything.....



On my tour last summer, I had this happen. Needed one more link in my chain. Since I couldn't do that, we had to lock out the derailleur so I couldn't use the largest cog on the cassette.

[Triskeliongirl]

I think you are right. I researched more on the capacity of the derailleur and it should be fine. I thought it was just a link too short, but when I compare it to other bikes in the house it looks a lot too short. GRRR, after getting the derailleur so nicely adjusted I have to start over. Do you know if I can add links back just anywhere (I still have the excess chain that was removed) or should I use the starter link. DH did the chain cuz I had trouble getting the pins in and out, but maybe if I practice on the old chain first, or does it really take a lot of hand strength?

[DebW]

You can put chain links back in. Obviously you have the chain tool. You probably want it a couple links longer than the old chain. If you have a power link in this chain, remove that and start there. Otherwise break it anywhere. Starting to drive out a pin can be a bit tricky. Make sure the chain tool is really centered over a pin - you may have to back off and try this a couple times before you're perfectly centered and the pin will start moving through the near plate. It can take enough force to make your hands uncomfortable if the tool is small. As you push the pin out (this also applies to the small piece of chain you are going to reinsert), push the pin until it is almost flush with the inside plate but still sticks out to the inside a tad. This will make it easier to start reinserting. If you leave that tad bit of pin inside the plate, you'll have to bend the chain link sideways a bit to pull the chain apart. As you're driving the pin out and getting near the end, stop and pull the tool off and try to break the chain by twisting and pulling. If it won't come yet, go another 1/2 turn and try again. Do that until it comes apart.

To put in the new links, attach the new piece of chain to the long chain. If you left that tad of pin inside the plate, it will snap in. If not, you'll have to hold the chain ends together as you start driving the pin with the chaintool (it can be done, but it feels like you need at least 3 hands to do it). Start slowly (and back off and try again if necessary) and make sure the tool is really centered over the pin. Once it gets started, it should drive in easily. Stop when the pin is centered between the outer plates. Now remove the tool, but don't lose that link. The link you just drove together will normally be stiff, that is, it won't bend freely. So now you use the "stiff link" part of the chain tool. The chaintool will have 2 places to hold the chain, one at it's end which you used to drive the pin out and in, and another in the middle. The one in the middle is for stiff links. Put the chain there (if the chain pin is not perfectly centered, put the longer end by the chaintool pin). The idea is to nudge the pin of the chain so that the link (with no pressure from the tool on it's backside) spreads just a little. Bring the tool down snug against the pin and then turn it 1/8-1/4 turn. Remove the chain and see if it moves freely. If not, repeat the procedure another time or two until it does.

One caution: apparently some Shimano chains (don't know which ones or what years or if they still do this) required a new pin every time you broke the chain. Check the box that came with your chain.

If you have enough chain, it will be possible to shift into the big-big combination on the work stand. Check the L limit screw on the derailleur to make sure the derailleur doesn't go further than the inside cog. With the chain on the smallest chainring, pedal fast on the work stand and make the shift to the inside cog repeatedly. Turn the L screw until you can't make that shift, then back it off until the shift occurs comfortably. Don't turn it any further than necessary. If you find the derailleur still hitting spokes after all this, then perhaps the new cassette sits closer to the wheel than the old one. A spacer behind the cassette could fix this. Only other cause would be a bent derailleur or hanger, but unlikely since he had no problems before. Good luck.

[DebW]

The other thing to check about chain length is that when you go into the small-small combination, there is no chain slack. So when you are about to put the chain together, put it in that combination and by hand pull the chain to where the links you plan to rivet together are in line. You should be pulling the rear derailleur jockey wheels out of their slack position and fighting tension in the derailleur spring. If you're doing that and you have enough chain to go into the big-big combination, the chain length is generally OK. Though some derailleurs will work better within some range of jockey wheel angles.

[Triskeliongirl]

Wow, you guys are great. Looking at it this morning, I am pretty sure the chain is simply too short, cuz if I hold it as if there were a few more links the rubbing stops. Also, my husband made it one link shorter than before, but since the casette is larger it probably should have been 1 link longer so it is actually now 2 links short. I will fix it after work tonite, but I am wondering if part of my problem with the chain tool I have is that I bought one that is mobile for traveling, but perhaps harder to use. Deb, can you please recommend a really good chain tool and I'll stop by my LBS and pick it up on my home from work tonite. I know in the short term I am spending more on tools than service, but in the long term its worth. I LOVE being able to keep our bikes running well.

[roadfix]

As mentioned, check chain length and adjust L limit screw. Ideally your chain should be just long enough to work with a big ring/big cog cross chain combo with the rear derailleur stretched somewhat.

[DebW]

Yes, the small chain tools are murder on your hands. They can do the job if your pain threshhold is high enough, but a larger tool is much easier. I currently use the Spin Doctor? Universal Chain Tool (http://www.performancebike.com/shop/...tegory_ID=4204) or something similar. It's not real large, but the edges are rounded and it's long where it needs to be for leverage. Costs about $9. If you want the real Cadillac, get the Park CT-3 Chain Tool for about $30.

[Triskeliongirl]

I will buy the CT-3, it looks like a dream THANKS for the rec! I have found that good tools make this stuff soooo much easier. I am using dura ace 9 spd chains. Do you know if I need to use a new pin each time with that chain? What is the best method for determining optimal chain lenth. I was told to wrap it around the largest front and rear rings, without threading through the derailleur, and I also read the pulleys should be on top of each other when in the large front ring and middle region of the casette. What method do you ladies use to get it right the first time? I also messed up my bike, and need to take out at least a link since on my bike I am getting the pulleys to hit my chain when in the small rear big front rings (even though this is a forbidden gear I think the chain is too slack as it always drops easily).

[DebW]

I was hoping someone else would answer your last questions, because I don't really know more than what I've already said. Without being familiar with your particular derailleur and cog combinations, I don't think anyone can tell you how long to make the chain, except long enough for the big-big and not too long for the small-small. As roadfix said, not longer than necessary. You can probably get it right on the first try. As far as whether you need new pins for a DuraAce 9-speed chain, ask at your LBS. I see that loosescrews.com sells DuraAce-Ultegra 9-speed chain pins in bags of 5, so maybe you do need a new one each time.

[matagi]

Yes, you do need a new pin each time you break the chain - far better to get a removable link (which makes breaking the chain a breeze), there are a few different brands out on the market.

We used one of the online calculators to work out chain length - try this one:
http://www.machinehead-software.co.u...alculator.html

Or, the other way to do it is to feed the chain around the two largest cogs (including through the derailleur) and then pull the chain tight so the derailleur arm is almost all the way up.

[roadfix]

Or, the other way to do it is to feed the chain around the two largest cogs (including through the derailleur) and then pull the chain tight so the derailleur arm is almost all the way up.

That is the method I use but I add an additional link.

[Triskeliongirl]

All fixed!! I successfully took one link out of my husband's chain and added one to my chain ALL BY MYSELF. The new chain tool made a big difference. I wasted my money on the portable one. The derailleur no longer hits the spokes on DH's chain, and is no longer too slack in the low/low combo. on mine. I was worried it would throw the indexing out but the shifts are all still great. Its also interesting to me, that I posted this query on a coed site, and all the men that responded insisted I had a bent derailleur and that I should take the bike to my LBS. This didn't make sense since the only change I made was to swap out te cogset. Yo

[roadfix]

Funny, I would have suggested checking for derailleur hanger misalignment over at the coed site too...

[Triskeliongirl]

The best was after our ride today, when DH told me that his bike has never shifted so smoothly, even after bringing it to a LBS to be professionally done. I am so stoked on doing this stuff myself, that i just bought a frame on ebay to build. This bike built up w ultegra sold for $2000 new (2003 terry isis, reynolds 853 steel), and he sold me a brand new never been built frame for $100! I had recently replaced all the parts on my 2001 classic, but then noticed the frame is starting to rust, so the plan is to transer the parts over. The guys at my LBS suggested having them do the headset though, which makes sense to me. I am also thinking to get S/S couplers installed first, to make a nice travel bike. Do you guys think I am better off with a steel or carbon fork, if I want to use it for light touring (i.e. how much weight can you carry with a carbon fork?). I have a steel fork and headset from my crashed 2001 terry classic in the same frame size that I think would fit, but how much heavier are steel forks than carbon, in general?