IllinoisGWrider

I'm new here and i hope this is the right place to post this, I apologize if it is not

but i recently bought a second hand (hardly used) mountain bike from a friend and it's been working great...up until today (about a week in to owning it). I was heading out to my usual trail, about half way down my block I slip a gear, at the end of the block my lock ring completely comes loose.

I walked the bike back home removed the rear wheel, set my sprockets back in place, tighten the lock ring and go back to try it out, I change gears and the lock ring pops off again.

I was wondering what the problem might be and if it can be fixed, any help would be greatly appreciated, the bike is a Honda trail pilot

below are two pictures of my rear assembly if it helps

https://i12.photobucket.com/albums/a2...4-09190906.jpg

https://i12.photobucket.com/albums/a2...4-09191926.jpg

FBinNY 

That's not a typical cassette hub, but is a freewheel which uses a lockring to hold the sprockets on the freewheel body. There aren't that many of these around, which means that finding the right tool to engage the lock rings inner splines difficult. The lockring needs to be seriously tight so it can't come loose. You might also benefit from using some Locktite to keep the lockring in place, but if you go that route, make sure the ring and freewheel threads are clean (really clean) and dry.

IllinoisGWrider

Thanks for the tip, I think we have some locktite around the house somewhere. Would you know of anything else that might cause this problem?

FBinNY 

Freewheel and cassettes lockrings don't have much reason to get loose since serious reverse torque on the sprockets isn't possible. I suspect it was never tightened properly to start. It's possible it was the cross threaded and felt tight when it wasn't, or that the threads are stripped or damaged and it cannot be tightened. Either way, at this point, I wouldn't worry about the past, and just fix it and ride.

If the thread is OK get it as tight as possible. Of you don't have the right tool, try driving it around and setting it with an old screwdriver or dull chisel against the internal splines and/or use Locktite to keep it there.

onespeedbiker

That DNP freewheel is pretty low on the food chain. Looking through some other posts, that silver ring has a bad habit of stripping/popping off. Unfortunately you may find that even if you manage to tighten the lockring, there will be a good chance it will just pop off again. My recommendation is remove the entire freewheel and replace with a Shimano 7 speed (the 13-28 runs about $14), which is a really well made freewheel at a very low cost. Some of the DNP freewheels take a standard Shimano Park FR-1 tool for removal, others take a DNP tool. The tool I'm talking about would not tighten the lockring, it would loosen the freewheel from the hub using the splines that surround the axle. If this is what you want to do, you could probably even do it without the tool. Sheldon Brown gives these directions to disassemble the freewheel and then removing it with a vice or pipe wrench https://sheldonbrown.com/freewheels.html#disassembly. Then just screw on the new Shimano freewheel, which will tighten itself as you ride.

IllinoisGWrider

Thanks for the advice both of you, if the freewheel has a rep for loosening no matter what I'll probably end up picking up a new one, I'm stuck shopping at walmart since the only bike shop near me doesn't have anything cheaper then 60 dollars, would this set be okay? https://www.walmart.com/ip/Shimano-Freewheel/13012509

IllinoisGWrider

and I maybe a totally bike newbie, but isnt this a freehub and not a freewheel?

juls

You are right-I've never seen a freewheel with a lock ring (EXCEPT MAILLARD) That is a freehub.

Airburst

You've never been to my bike co-op, we had about 5 of them kicking around at one point. Fairly new, fairly cheap ones as I recall.

To the OP. That is a freewheel doing a darn good impression of a freehub, but it's still a freewheel. It's certainly rather confusing.

onespeedbiker

This a freewheel body; some came with lockrings..

IthaDan 

Yeah, NO.

That's what a freewheel looks like when you take the cogs off. You might have to take the locknut off the axle to get a tool in there, but there's a keyed round hole the freewheel tool would slide in. After that you're just driving the bus at the bench vice to get the freewheel emancipated.

IllinoisGWrider

Thanks a lot for clearing that up you guys, I guess all that's left is to order the new freewheel, I take it I'd need a 13-28T so im thinking about picking up this one https://www.amazon.com/Shimano-MF-HG3...pr_product_top