420 Chain for 66cc bike

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,688
You have many different chains to choose from and many reasonable reasons for choosing them. None of these reasons are it's breaking strength under tension. ☝😾

Rant begins! 😝🍺
You can run nine speed derailleur chain with your tandem mountain bike with two muscle dudes stomping uphill in lowest gear and it'll be strong enough. You can run the same piddly little nine speed derailleur chain on your little China Girl too. I do!
You can run 3/16" narrow bmx racing/ single speed chain or 1/8" standard bmx freestyle chain on a highly modded brand name 69cc bicycle engine and it'll be strong enough, many of our members do this.
Use any chain you like but it's pointless to debate about what is the strongest size chain between a #415 and #41 because its completely irrelevant. They're both massively overkill, strength wise. 😤

Quality is relevant. The width of your sprockets and whether you want to alter that is relevant. The clearance with other bike parts like stays and the clutch cam housing "sprocket cover" is relevant. The resilience in malfunction situations, as completely distinct from the chain's "strength" or breaking strain as designed, is relevant. Cool motorcycle look is as relevant as you want it to be. The lateral stiffness is definitely relevant, God knows my nine speed derailleur chain is not laterally stiff lol its like an epileptic eel! 🤭
We have plenty of variables to debate that affect how well / strongly / reliably our bikes drivetrains run. Quality clearly matters looking at the previous post. 😖

Also rant continues! 🤪🍺
What is this about a chain lasting years on a sprocket? Special chain that doesn't wear, or wear the sprocket?
I mean there's different ideas of what "runs", depending on how low your standards are. Someone else's idea of "running" could be completely different from my own. 

Sorry that was a bit of a rant. I saw a spider and tried to swat it with a fin (I know) and I missed and jumped off the ladder and hurt my toe. 🍺🤫

The point was there somewhere..
Chain wears sprockets, and with sprockets, and from sprockets. The crappy eccentric or alloy sprockets we have, too! Everything is bound to wear quickly.
You can run the chains and sprockets in sequence to extend the lifetime of your drive train parts. You just have to check wear and rotate parts when you're doing the routine maintenance.
Some people do run the same one set of chain and sprockets together until the chain skips no matter how much you tension it. That's the lowest amount of maintenance you can do but also the lowest miles per dollar before failure or unacceptably poor running. I do that with my electric bike that has the motor in the hub!
I believe we can get more miles of smooth running for each $ spent by rotating parts. See what wears more and use more of them. Chain, definitely. Idk what the alloy sprockets are like as I use bicycle parts.
I hope you would look at these things when you are maintaining your bike, that you would not actually literally leave the chain on the engine sprocket for the last few thousand miles and never see the sprocket uncovered and cleaned so you can inspect it, even if you run only one set of drive train parts at a time.
 
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Vikingimike01

Active Member
Joined
Jul 1, 2018
Messages
955
I bought cheap KMC chain for my 6 speed shifter kart with the modded engine that has the tuning exhaust lmfao guys these engines are putting out 2hp stock, why would you need so strong chain? Are you going to a race with a 20+hp engine, and a 12 speed dual clutch???

You know what's two horsepowers? It's not much. One horse can output 15HP for a small amount of time when sprinting. The top guys in bicycle racing put out almost one horsepower for 10+ minutes. You? Maybe that for one second. Go to your lowest gear on your normal mountain bike, and start pedalling up a mountain as hard as you can. It should be easy to pedal. I'll guess you make that almost 1 horsepower for a very brief time. Your chain? Do this 10 times. Do this 100 times. Do this a thousand times. It will be OK. Guys, stop worrying about your chain. But I do know one thing, if the stock, cheap, sh**ty chinese 415 chain works, why wouldn't a quality or even a medium quality BMX or any other chain not??

2 horsepowers is around 1491 newton meters / second. Let's round that up to 1500, because, why not. The cheapest KMC chain I could find, wich I'm not even sure what size it is, has a breakage point of 9316 newton meters / second. What does that mean?? It means, you have nothing to worry about. Means, it can handle 2 horsepowers. 6x2 horsepowers. Although, that would really be pushing breakage point. Just don't worry. It was a quick google search, if I could do it in 10 minutes, who doesn't really know much stuff about physics, or all this chain stuff, if you know what you are looking for you can do it in less time.
 

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
670
I bought cheap KMC chain for my 6 speed shifter kart with the modded engine that has the tuning exhaust lmfao guys these engines are putting out 2hp stock, why would you need so strong chain? Are you going to a race with a 20+hp engine, and a 12 speed dual clutch???

You know what's two horsepowers? It's not much. One horse can output 15HP for a small amount of time when sprinting. The top guys in bicycle racing put out almost one horsepower for 10+ minutes. You? Maybe that for one second. Go to your lowest gear on your normal mountain bike, and start pedalling up a mountain as hard as you can. It should be easy to pedal. I'll guess you make that almost 1 horsepower for a very brief time. Your chain? Do this 10 times. Do this 100 times. Do this a thousand times. It will be OK. Guys, stop worrying about your chain. But I do know one thing, if the stock, cheap, sh**ty chinese 415 chain works, why wouldn't a quality or even a medium quality BMX or any other chain not??

2 horsepowers is around 1491 newton meters / second. Let's round that up to 1500, because, why not. The cheapest KMC chain I could find, wich I'm not even sure what size it is, has a breakage point of 9316 newton meters / second. What does that mean?? It means, you have nothing to worry about. Means, it can handle 2 horsepowers. 6x2 horsepowers. Although, that would really be pushing breakage point. Just don't worry. It was a quick google search, if I could do it in 10 minutes, who doesn't really know much stuff about physics, or all this chain stuff, if you know what you are looking for you can do it in less time.
Not everyone is using a stock chinagirl, but I get what you are trying to say. 415 chain works great if you use a quality one, but the stock kit chain is garbage. #41 is stronger, lighter, and cheaper than a 415 chain while being compatible with the same roller distance so for most builds IMO there is no reason to use anything else...it works on our same sprockets (unlike 35 and 420 which both need different sprockets), has better chainstay clearance, and is easier to find than 415 in many places. #35 chain is similar strength to #41 and even lighter, an even better choice if starting from scratch, but you need new sprockets front and rear which doesn't justify the extra cost if you just are looking to replace a prematurely broken chain and keep your low miles sprockets.

FWIW Scotto is one of the most well known and experienced 4stroke builders and has made a ton of nasty 212 bikes and he has stated that every one has used standard #41 chain.
 
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