Effects of a broken rear derailleur pulley tooth...
Although I was being very careful last night while installing a new rear derailleur cable and shifters on one of my tandems, I managed to break one of the teeth on the top rear derailleur pulley on a new SRAM X.9 rear derailleur. I know these pulleys are available for replacement (looks like $17 - $20 for a pair), but I am wondering if this is a "must fix now" type of repair to avoid more damage or if things will function properly for now with one missing tooth on the top pulley? Shifting seems to work fine in the work stand, but that's the work stand - and not real riding.
Any thoughts? I do have two pulleys from a SRAM ESP 7 rear derailleur, but I imagine they might not fit or work with the new X.9.
Have never broken a pulley in 29+ years of riding as a duo, but have worn out pulleys.
Most pulleys are interchangeable, although not all.
If it works on the workstand try it on the road with stoker aboard. If it's no bother shifting, use it as is, although we suspect it'll do some skipping; contact the dealer/company and explain your dilemma. The last thing they need is bad publicity; bet you'll get a new pulley!
Pedal on TWOgether!
The only things I have ever seen that would foul a rear derailleur involved chain derailment on contact with the bottom pulley, specifically, twisted link which would jam before getting on, and then skip on the drive cogs, and too much chain (don't use the small/small combinations, duhhh....). Modern derailleurs tend to work properly even when the chain is slack.
It seems to me that with the short distances to the bottom pulley and to the cassette and with other rollers in contact with the pulley, that nothing bad can happen. The chain will always line up with the pulley properly, and the other rollers will keep any pitch variability from being an issue by keeping the timing right. There is a slim chance that some of your shifts will be a tiny bit late, because that one missing tooth will keep the derailleur jockey pulley from applying lateral pressure to shift, but a half-inch of chain travel later, that won't be an issue. Seems to me it would take a real expert (like princess-and-the-pea) to notice the difference. I think you're okay.