Jerry Jones

Hi guys, not sure if this is the right place...

I had a crash yesterday, some guy stepped in front of me on the cycle lane and I landed pretty hard.

Well, the main problem now is that my rear derailleur isn't letting me select gears 4-7 (Shimano 21 speed), doesn't matter which front cog I'm on.

The landing was hard enough to twist the handle bars right round and wedge them under the frame, but their released now and the bike seemed basically fine - but some internet research led me to check the back wheel closely and it now has a slight wobble in the spin.

Does anyone have any advice about how I can repair it myself? Is it simply gear-cable tension? Or is it more like my bearing/axle is damaged?

Thanks for the help.

berner

The video shows a method of truing a wheel without the special tools a professional bike mechanic would use. You will see in the video the narrator using a metal tool as in indicator of where the wheel is off true. I use a magic marker myself which leaves a visible mark that would indicate high and low spots. Once you have marked highs and lows, spokes need to be tensioned or loosened and there is a special small wrench that fits on the spoke nipples to turn them. The video will provide a good guide to the basic idea but I would add that some patience is needed by a beginner.

There is also the possibility that the rear derailler, which moves the chain from one gear to the other may have been bent a bit, depending on which side the bike fell on. Should that be the case, even with the wheel trued perfectly, it will likely shift poorly and that will require a special tool to determine and a bike mechanic to straighten it. If so, it will not be expensive, requiring less than 10 minutes. Good luck.

Wheever

The derailler hanger got bent, I suspect. Probably a bike shop wouldn't charge you much for that. Happens often enough that I bought the tool to do it myself.

hcgaloi

If derailleur hanger is bent, you can buy Park Tool derailleur alignment for $71 on Amazon and fix it yourself.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

good luck