Ghostrider911

I was out riding the other day and noticed that if I selected rear gears 1-3, the gear shifter would hit the spokes. I got around this by staying in gears 4 and higher to get home. As you can see in the photo below, the spokes will come in contact with gear shifter in lower gears. It doesn't look like there's enough room between the wheel and the shifter. What happened and do I have to move the wheel over to make more room for the shifter? Also, the smaller gear which is circled in green broke such that half of the gear is missing (probably the spoke took it off). How do I go about fixing it? It looks like the bolt holding it in place can be removed, and it looks like a hex bolt. Would that be standardized and if so what size would I need?

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Also, it looks like a screw fell out of the back of the gear shifter (green arrow). Any idea what the screw does and how should I fix?

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shouldberiding

You're missing one of your limit screws. That's what prevents cable pull/spring tension from pulling the derailleur to far one way or another and throwing the chain.

Also, it looks like your derailleur hanger is WAY bent. I mean, a LOT. That'll need to be replaced. It's contributing to the issue because it's bent inwards towards the spokes.

I'd hesitate riding that wheel until you get it checked out by a bike mechanic.

Monster Pete

Yeah, looks like the derailleur's taken quite a whack at some point. I agree with getting the wheel checked out. At the same time, see if the bent hanger can be straightened out. If the derailleur's not bent, and you can get hold of a replacement screw, it should be fine, otherwise head to either the bike shop or dump and get a replacement.

Sixty Fiver

Your hangar appears to have quite the bend in it... if your bike has a removable hangar this will need to be replaced and if it is an integrated hangar on a steel bike it can be straightened.

Ghostrider911

Yeh, it probably is too far bent -- it caught the spoke and locked up the rear wheel...I was going about 5 mph up hill at the time. It looks like I can replace the whole part with not too much difficulty:



I think I just have to take off the big aluminum bolt...think it requires a hex driver. How much would that part cost? I assume it's generic. If it's $30 or less, I'd probably just buy a new shifter. Bike is a Mongoose MGX-D50i. Consensus seems to be that the wheel does not need to be moved, correct?

Update: Apparently the derailer sucks: https://www.mtbr.com/cat/drivetrain/d...16_116crx.aspx

So now I'm leaning towards replacing it. How do I find one that's compatible with my bike?

DannoXYZ 

No, you cannot just replace the derailleur because the frame is bent. The part that the derailleur bolts into is called the "derailleur hanger". Some bikes have a soft replaceable hanger. It does not appear that your bike has one. So it can be manually bent back. To really do a proper job, you need an alignment tool to verify that the hanger is vertical and in-plane with the frame fore & aft. Check out this link:

https://www.downtube.com/Adjustment_I...illeur_Hanger/



BTW - the shifters are on the handlebars.

waldowales

This looks like a case where a trip to the local bike shop would be the wisest course of action. Let them explain the problem and the nomenclature as they repair it, so you'll be better prepared if it happens again. Do-it-yourself is a wonderful thing, but in this case, trying to go ahead without professional help will likely result in further damage.