Front Chainring Issues

[CallumGNC]

I was riding my 2022 Cube Reaction Hybrid Pro today and my chain snapped. On inspection my chainring was bent too and moves a lot from side to side. No idea how this has happened but I'm wondering how to change the chainring, which one to buy (this one was fine before the damage) and also what chain would be good? Thanks

 

[Stihldog]

I was riding my 2022 Cube Reaction Hybrid Pro today and my chain snapped. On inspection my chainring was bent too and moves a lot from side to side. No idea how this has happened but I'm wondering how to change the chainring, which one to buy (this one was fine before the damage) and also what chain would be good? Thanks

Possibly an ethirteen chainring may fit. You’ll need a few tools (torque wrench, crank puller, Allen keys, castle nutt socket etc).

If your chainring became lose or was bent from an impact …your chain could break. Replace those things. Some blue loctight may be necessary also( castle nutt threads). If you’re unsure or not comfortable with this part of the drivetrain …have your lbs do the work.

Replace the bearing seal kit while you’re at it. (Easy and cheap preventative maintenance).

 

[CallumGNC]

Possibly an ethirteen chainring may fit. You’ll need a few tools (torque wrench, crank puller, Allen keys, castle nutt socket etc).

If your chainring became lose or was bent from an impact …your chain could break. Replace those things. Some blue loctight may be necessary also( castle nutt threads). If you’re unsure or not comfortable with this part of the drivetrain …have your lbs do the work.

Replace the bearing seal kit while you’re at it. (Easy and cheap preventative maintenance).

Great, thanks for the info. I think the chainring had been slightly bent after some trails recently but I hadn't noticed. I'm going to have a crack at fixing it myself once the parts and tools arrive

 

[Stihldog]

There’s some good tips and advice hidden in the forums (use the search) for your bike.


I keep these as spare’s just in case…but I service several other “Bosch” bikes as well.

 

[Montana St Alum]

What chainring did it come with (just get another) and what cassette are you running? If it's a Shimano drivetrain then a Shimano chain might be your best bet and if it's a SRAM, a SRAM chain may be better. The differences may not be particularly notable though. Using the old chain would be an easy way of sizing the new one, so don't throw it away.

 

[CallumGNC]

Soooo a couple more issues I've ran into whilst fixing my bike - the chainring I've bought is an exact copy, apart from a protruding ring which juts out toward the crank arm (see pictures of new and old chainring for comparison). It doesn't seem to cause any issues and could be an upgrade to further stop dirt getting around the base of the crank arm and motor, but what do you guys think? I've not been able to test it as yet due to...

The castle nut being pretty well knackered, I'm hoping that the part it screws on to isn't also knackered (again, see pics). Where can I find the right castle nut and castle nut socket? I've already bought a castle nut socket although it is too big, so don't want to make the same mistake again.

Cheers all

 

[Stihldog]

Soooo a couple more issues I've ran into whilst fixing my bike - the chainring I've bought is an exact copy, apart from a protruding ring which juts out toward the crank arm (see pictures of new and old chainring for comparison). It doesn't seem to cause any issues and could be an upgrade to further stop dirt getting around the base of the crank arm and motor, but what do you guys think? I've not been able to test it as yet due to...

The castle nut being pretty well knackered, I'm hoping that the part it screws on to isn't also knackered (again, see pics). Where can I find the right castle nut and castle nut socket? I've already bought a castle nut socket although it is too big, so don't want to make the same mistake again.

Cheers all View attachment 140356 View attachment 140357 View attachment 140358

Regarding new chainring; There may be a plastic washer and/or a brass “o” ring behind the the chainring. Make sure that the offset is the same as the original.

Regarding the castle nutt; it’s softer metal (alloy) and is likely designed that way on purpose. If you accidentally strip the threads on the castle nutt …replace it. The fine threads on the crank-shaft should not be damaged though. (Use your watchmaker skills here).

Regarding the bearing seal kit; I would recommend that you install one since you’re at this stage. You may have to modify a cir-clip removal wrench to remove both cir-clips. Liberally apply the “green grease” in this area. The bearing seal kit generally has grease, new seal, and new cir-clips for both sides of the crank shaft.

Torque everything back to spec. Add a small bit of blue loc-tight to the castle nutt threads if there is a problem with this part coming loose. There are some other tips and advice for the castle nutt if this happens.

Steady the bike, be careful with cleaning fluids, (don’t want to wash away bearing grease). A little bit of patience if this is your first try.

 

[CallumGNC]

Regarding new chainring; There may be a plastic washer and/or a brass “o” ring behind the the chainring. Make sure that the offset is the same as the original.

Regarding the castle nutt; it’s softer metal (alloy) and is likely designed that way on purpose. If you accidentally strip the threads on the castle nutt …replace it. The fine threads on the crank-shaft should not be damaged though. (Use your watchmaker skills here).

Regarding the bearing seal kit; I would recommend that you install one since you’re at this stage. You may have to modify a cir-clip removal wrench to remove both cir-clips. Liberally apply the “green grease” in this area. The bearing seal kit generally has grease, new seal, and new cir-clips for both sides of the crank shaft.

Torque everything back to spec. Add a small bit of blue loc-tight to the castle nutt threads if there is a problem with this part coming loose. There are some other tips and advice for the castle nutt if this happens.

Steady the bike, be careful with cleaning fluids, (don’t want to wash away bearing grease). A little bit of patience if this is your first try.

Thankyou so much for your help mate, I'm going to crack on with this at the weekend and see how it goes