Chain retention on ...
 

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Chain retention on a kid's bike

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My son has an Orbea MX24 and is getting a fair bit more adventurous. While he's building up jump sizes there are a fair few harsh landings that are causing the chain to come off. Same happening from time to time on rougher trails. Any suggestions?
Stock crank with small plastic chain helper clamped to seat tube.
Stock cranks with single ring
gx 2x10 mech, I think clutched? May not be.

My usual approach would be narrow/wide ring, but that would require new cranks.
New mech would probably have a long cage which would be a liability.

Rapidly growing out of this bike so I'd quite like a solution that's either cheap or can be transferred to a new bike.

Alternatively, N+1...


 
Posted : 15/10/2023 8:28 am
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I seem to remember we had a Stumpjumper that had a tensioner that fitted on the chainstay with 2 tie wraps and the chain ran through it. There's probably an aftermarket version

Blackspire Stinger may fit and work


 
Posted : 15/10/2023 8:42 am
zerocool and zerocool reacted
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Second the Blackspire stinger. Works well


 
Posted : 15/10/2023 8:53 am
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Good shout on the stinger! I've got one on my pumptrack bike.
Time to try and find my tapered BB tool... 😀


 
Posted : 15/10/2023 9:45 am
zerocool and zerocool reacted
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A stinger likely doesn't have enough adjustment for the small chainring but if it does, replace the roller with a jockey wheel, far smoother and quieter.

Taking a few links out of the chain will help it stop flapping about.


 
Posted : 15/10/2023 9:47 am
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I went with 1x10 conversion as I wanted to fit shorter cranks. 11-34 cassette and used zee freeride mech with clutch was pretty cheap. I found a HT2 crank on eBay of the right length but other bikes have square taper and a snail N-W ring for £10.

Will move it all over to the next bike and refit the old stuff.


 
Posted : 15/10/2023 9:59 am
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Why would you need new cranks? If they're the same as the MX20 then they're 5x110bcd which you can get NW rings for.


 
Posted : 15/10/2023 10:03 am
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You want cheap?

Take a reflector bracket and make a chain guide that zip ties to the chain stay. Works a treat.


 
Posted : 15/10/2023 10:10 am
zerocool, ads678, ads678 and 1 people reacted
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Superstar still have cheap Stinger copies for about £12 (I think). They also do upper guides and full guides if needed.


 
Posted : 15/10/2023 1:27 pm
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Short length of garden hose (20mm) 

Chain runs through

Cable tied X2 to the chain stay


 
Posted : 15/10/2023 1:41 pm
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Well blimey, thanks everyone, especially @squirrelking for making me go outside and look at the bike as opposed to a blurry library image. Looks like they're removable after all! Albeit seemingly measuring at 4x112, which can't be right, so assuming 4x110. This makes things much easier and cleaner!


 
Posted : 16/10/2023 1:30 pm
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<<New mech would probably have a long cage which would be a liability.>>

fitted a Microshift compact rear mech to mt daughters'  24" Whyte:

https://www.microshift.com/models/rd-m6195s/

Short cage and has a clutch, and match to their 11-38t cassette.


 
Posted : 16/10/2023 1:52 pm
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Do the old CX mech spring trick, take the cage stopper off and wind another rotation of tension on the mech spring and then put the stopper back on.


 
Posted : 16/10/2023 3:06 pm
 5lab
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aliexpress has a bunch of cheap kids-length cranks for those with rivited chainrings


 
Posted : 16/10/2023 3:08 pm

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