Hi. I'm pretty new to fixing bikes. I recently bought a bike for my kid that is our project bike and his bike to use after we're done with it. We've replaced the brake pads, brake lines, shifters (the twist handle kind), shifting lines, and trued the wheels. We can't figure out why the back gears will hop off the last big gear and off the cassette. I think maybe the derailleur is bent, plus one of the H/L adjuster screws was bent and I straightened it and am able to use it now, but regardless I can't get the last gear to work because it just goes too far in. Attached are some photos. Tires are too wide for me to get a straight shot. Please and thanks. If any more photos are needed that I can get, please let me know and I'll try to get them.
by Hows-It-Goin-Buddy
4 Comments
Oh and I forgot to mention it’s a 7 speed rear derailleur. If I need a new one, what would you recommend buying? I’m a bit confused because there are so many options, and many don’t have the closed circle hole to use and instead have like an open slot.
Thank you!
Take a large crescent wrench and get the jaws close together and bend it back. It should be vertical when viewed from behind. A large pair of pliers might work too.
https://preview.redd.it/35cx3dqjohjf1.png?width=39&format=png&auto=webp&s=038af4b8cb45a7215c06da082324a152f0e04c6f
This part is what’s bent, the derailleur hanger. Take the bike into a shop/coop, and they’ll be able to straighten it out or order a new one in for you.
The hanger is bent, maybe the rear d smidge but most of your issue is the hanger. Make sure you tighten the mounting bolts for the hanger before straightening the hanger itself.