Hello, I'm a MTB noob and I just bought a used Trek Roscoe 7 (2022). Stupid me paid too much for it, without really knowing what I was doing. Anyway, I was having some shifting issues, so I decided to follow this guide to adjust my rear derailleur. Well, I can't really complete the steps in the video because my gears sometimes slip and sometimes jump a gear while going up and down, usually around the 8th, 9th and 10th gears, and I can't find a single indexing adjustment that works for all the gears. So, I started taking a closer look, and realized that not only was one cog tooth bent, but my tire appears to wobble as it rotates, and also the cassette seems to wobble back and forth as well.
I'm a bit of a DIY guy, so I don't mind spending some time to fix it, but where should I start? With so many moving parts, I'm not sure where to begin. I'm also wondering if this is beyond fixable.
I took the cassette apart and cleaned it; it's got the four largest cogs on a spider, and the remaining slot into it, with spacers in between. Then I bent the offending tooth back into place with a couple pairs of pliers. It's not perfect, but definitely better than where it was. I reassembled it and tested it. That's when I realized the axle wobbles slightly, and the tire more than slightly. You can see this at the beginning of my video. Then you can see the chain jump gears as I'm shifting up and down.
Do I just need to replace my entire wheel? Please help a noob out.
Multiple issues with rear wheel. Where to start, or am I hosed?
byu/kendaop inbikewrench
by kendaop
12 Comments
My local bike shop charges $15 to true a wheel
You can attempt this at home too, if you have any loose spokes
Can’t speak to everything but cassette wobble is perfectly normal.
Just take it to a shop.
Cables may be stretched, chain may be stretched, cassette may be worn, wheel out of true, etc.
They will inspect and fix it once, you can maintain from there.
Welcome to mountain biking.
If you have not used the barrel adjustment at the shifter to micro adjustthe cable. Then The gears that are jumpy could be caused by a bent derailleur hanger or cage. There is a special tool that one would need to straighten the hanger.
Could also be the b tension screw is not adjusted correctly
Cassettes do wobble or appear to.wobble which is different than the lock ring not being tight enough.
If it is just the tire being wobbly check to see if the bead is seated correctly, or if the rim is bent. If those are OK you can ride so long as its not rubbing the frame or replace it. Wire bead tires are cheaper than folding ones
The cups in your wheel bearings are not adjusted properly. This is causing the wheel hub to wobble on the spindle. I’m not sure exactly what kind of bearings that this wheel uses, but sometimes you can adjust them using a “Cone Wrench.” My only experience with this was an old Liv that had a 7-Speed freewheel. Good luck!
[https://www.youtube.com/watch?v=opommURFB4o](https://www.youtube.com/watch?v=opommURFB4o)
This video shows the entire disassembly and greasing, but you really only need to do the last step. If this doesn’t work you may have a problem with your free hub.
Note: You can probably confirm this by seeing if you can move the wheel yourself. Sometimes the axle itself is bent which can cause a wobble.
unless you give it a go on a lathe it will keep wobbling but its fine, also perhaps the axle could be bend a bit but also not big problems. just true the rim a bit
It’s hard to diagnose multiple issues with a shaky video and not a deep understanding of what’s going on. Bring it to a shop. Most will do a free estimate and give you a scope of work to ponder. If the cassette teeth are bent, that’s automatically a new cassette and maybe a chain if it’s as worn as you would expect to bent cassette teeth. Hub bearing tension can be adjusted. And Spoke tension can be adjusted if it’s not too far out of whack.
Sure its buckeld can u not see
Cassette wobble is normal. The amount of wobble decreases as the hub quality goes up.
First resolve the issues with the hub. Only then continue to the rim. If you cannot figure out the hub yourself, take it to a bike shop.
The wobble in the cassette is too large. It can indicate something is bent, or loose.
I would start by checking wheel movement. Since it looks from the specs that you have cartridge bearings, there should be no slack.
Once you finish with wheel movement, check that the wheel and the cassette spin freely without bindings. The cassette obviously should stop quicker due to the pawls, but there should be no bearing resistance for either.
Wheel needs truing to straighten. Skipping or slipping on the middle gears indicate a stretched chain (or the previous owner might have replaced the chainring with a smaller one without shortening the chain). I would say have a bike shop fix it for you. The bike shop near me would true the wheel for $20, replace the chain for $30 and toss in the derailleur adjustment for free, but your local bike shop might charge more. Save yourself a lot of grief and take it to a bike shop.
Hub/cassette wobble is normal, the skipping is easy fix when tuning up your derailleur. Go check out parktools YT channel for the best bike info on tuning or truing. Good luck!