Context: I’m new to all this stuff, got a new specialized allez sport and have taken it out for one proper ride. Found that when I’m in a high gear on my front gear and then drop the back gear to about this range I get this skipping up and down which is a nightmare to pedal on. What’s causing this and how can I avoid it? Thanks!
What’s causing my chain to skip up and down like this?
byu/throwawayboyotwo inbikewrench
by throwawayboyotwo
8 Comments
1. Your rear derailleur is adjusted wrong, but if it’s a factory new bike, then it seems a bit odd, but possible. Search youtube for videos on how to adjust rear derailleur
2. It might be that the links on your chain don’t move freely, could be a lack of lube, faulty chain (rare) or a quick link/joint pin that is too tight and doesn’t allow the chain to flex and move as it should
3.rear wheel seated inproperly, check that the rear wheel is on properly.
4.Someone who is a professional bike mechanic will come along and tell me that I’m wrong on all three and that this is a simple fix 😅
adjust the derailleur.
at this point I’m too tired of googling ‘park tool derailleur adjustment’ to copy the link but I’m sure you’ll find it
There are a ton of excellent videos on YT. l was able to adjust mine after watching several.
I find that sometimes when a bike is on the shop floor for sale people mess with the shifters without spinning the wheel which stretches the cables because the derailleur has nowhere to go. This also happens over time with new cables as you use it but usually after quite a few rides. Few turns of a barrel adjuster and you’re good to go.
Your indexing is not adjusted correctly. The derailleur is aligned too far to the inboard (hub) side. Full step through for a RD setup is below but assuming it’s not completely out of adjustment at the high and low it’s an easy fix. See that black barrel adjuster where the cable comes into the RD? Start turning that about a quarter turn clockwise until not only does it not try to shift up but you hear no noise of the chain rubbing on the next ring. Shift through all the gears except for the big and small and make sure you don’t hear any noise and if you do turn the barrel adjuster a quarter turn at a time until it stops.
If your shifting is still messed up follow the full setup guide or take it to a shop if you aren’t comfortable doing it. If you take it to a shop ask them to also check the hanger alignment for you.
[https://www.parktool.com/en-us/blog/repair-help/rear-derailleur-adjustment](https://www.parktool.com/en-us/blog/repair-help/rear-derailleur-adjustment)
How did you manage to install the derailleur pointing upwards? Does it improve aero?
Park tool has put out numerous great videos on how to index gears. If you plan on riding regularly you need to pay attention to this because it can often be fixed with a few clicks of the barrel adjustor. I can’t stand a chain that skips and it will happen as your chain/cassette/ derailleur age. If you ride full suspension, the longer the travel the more it will skip and it’s often finding the best adjustment while the bike is at sag. (I find that you really have to be on the bike when doing this right).
One thing that helped me understand this better, that is somewhat counterintuitive, but when you look at your derailleur makes complete sense, is that the lower the gear the higher the tension (specifically the spring) in the derailleur. However, clicking the barrel adjustor clockwise will fix a derailleur that sticks in the lower gear because that adjustment reduces the tension in the cable. I thought it was the opposite for so long because I always associated higher gears with higher tension, but one day I just looked at what was going on and it became immediately obvious. That being said, it’s always helpful to make sure the derailleur spring is clean and that your chain is adequately lubed when indexing.
There are hundreds of Youtube videos that explain how to adjust the rear derailleur. It’s much easier explained in videos than using words: [https://www.youtube.com/results?search_query=adjust+rear+derailleur](https://www.youtube.com/results?search_query=adjust+rear+derailleur)