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Drivetrain needed adjusting or something else?

661 Views 7 Replies 5 Participants Last post by cotton2us, Jul 30, 2008

cmd miler

Discussion Starter · Jul 29, 2008

Ever since a frame swap I've been having trouble dialing in my gears.

I have a Daytona 10 spd with only about 3500 miles on the cassette and 2000 on the Campy chain. The drivetrain is pretty noisy and occasionally doesn't want to go right into gear (more often at a slower cadence). In the stand I first adjust the rear limit screws, then tweak the tension with the barrel one way or the other to make it hit every gear. In the stand it shifts great -- right in. Still on rides it's causing issues.

On rides I've tried tweaking the barrel adjuster on the rear cable± 1/2 - 1 full turn and it seems like the tension is correct, yet I occasionally get the chain dropping down a gear (usually on a climb!) or not wanting to up... also before a climb.

I've cleaned the chain and use ProLink. When the shop installed the Campy chain, I don't know for certain if they reused the Campy links or not but I don't see and stiff links. I don't know that they work on many Campy groupos (none in the shop... and very few high end road bikes), but for my frame swap its who Cannondale said to go to.

Thanks

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JCavilia

· #2 · Jul 29, 2008

Shifters?

How much mileage on the levers? Sounds like it could be the shifter mechanism. The symptoms sound like tired g-springs. I don't know if that shop has the expertise to do the overhaul, but it's not really a hard job after you get the hang of it.

Some lube in the shifters might fix it up at least temporarily.

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cmd miler

Discussion Starter · #3 · Jul 29, 2008 (Edited)

Good thought. The levers have about 3500 miles of use (7yrs... I know, hey, I didn't ride the bike the first 4 yrs!). I've never done anything to them (as far as lube goes).

Update: I put the bike on the stand and shot some lube on the springs. I reset the rear limits (actually they were good as-is) and tested everything. As before all the gears lock in fine. BUT I did notice I don' always get a strong CLICK when shifting up to a larger cog. Shifting 12 to 13 especially, then its hard to shift to 14 without it going up to 15.

Perhaps the chain is ramping up to the next cog, but the shifter is locking in correctly, thus allowing the chain to drop back down?? I'm going out for another test ride.

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cmg

· #4 · Jul 29, 2008 (Edited)

here's a link of where to buy parts, Brandford bike, http://www.branfordbike.com/cgi-bin...&thispage=brake/brk05.html&ORDER_ID=117855460
a link on some instructions http://www.campyonly.com/howto/ergo_rebuild.html and http://www.nuttycyclist.co.uk/cycling/ergo-rebuild.htm Keep in mind what makes reassembly difficult is that your going to wind up the spring before re-hooking it.

Have you tried to take all the slack out of he cables before you start turning the adjusting barrels? disconnect the cable from derailluer, see if it drops the chain on the smallest cog, it should. Then turn barrels pulling them in, pull cable taunt making sure the cable ferrules are inserted all the way in adjusters and reattach to derailluer. the derailluer should not move after attachment. Take out slack by turning the adjuster at the head tube 1-1 1/2 turns, try shifting. If it stills make noise, put bike on stand in the noisest gear, adjust barrel on derailuer until upper pulley is aligned with the noisest gear and shuts up. usually the noisest gear is either 3rd from the top or 4th from the bottom. if this doesnt work it maybe that the cage on derailluer is bent. 3500 miles isn't much your shifters should be fine.

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cmd miler

Discussion Starter · #5 · Jul 29, 2008

Thanks. I'll give that a try. I built the bike up myself and it ran great. I had a frame swap and haven't been happy with it since. You suggestion is good -- start from scratch.

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Kerry Irons

· #6 · Jul 29, 2008

Pinched casing/cable?

cmd miler said:
Thanks. I'll give that a try. I built the bike up myself and it ran great. I had a frame swap and haven't been happy with it since. You suggestion is good -- start from scratch.

Since it started right after a component swap, I would look at the possibility of a pinched casing or cable, or even something so simple as the brake lever hood hanging up the shifter action.

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cmg

· #7 · Jul 30, 2008

are the cables running pararell to the down tube or do they criss cross under it? if they cross under it look there, one cable might be pulling the other.

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cotton2us

· #8 · Jul 30, 2008

Your problem most likely is a cabling issue. Had the same thing, on the stand shifted threw the gears fine, on the road sometimes delayed, more so in a upshift (towards smallest cog). It may help to understand the function of the shift- when the cable is not connected to the rear derailleur the position will be under the smallest cog . The springs in the derailleur will locate it there. When you attach a cable to it you have minimum tension on the derailleur cable. As you move to the largest cog you increase tension to overcome the derailleur springs that want to locate it back to the smallest cog. The smallest difference in friction between the cable and the housing will not give you a precise repeatable shift. IMO your shifter does not have enough miles for the g-springs or index gear to need rebuilding. If your budget is tight you can try lubing the cable housing, with tri-flow- also with a small drill using it with your hand remove any possible burrs at the ends of the cable housing hole so the cable slides easily. Clean the dirt and lube the bottom bracket cable guide as another possible area of trouble. Lastly since you mentioned a frame swap the cable housing bends may be incorrect for the new frame placement-check the park web site for more information on that issue.

http://www.sheldonbrown.com/derailer-adjustment.html

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