525 Vs 520 chain?

I have noticed on a few threads that people change from a 525 chain to a 520. Can anyone explain the difference please and why you would make the change

[jambo]

Less weight.

Thanks for the simple answer to my simple question. So there is nothing different in terms of longevity to the sprocket or chain?

thanks to the Mod who changed the title probably makes more sense now

[Ruffy]

520 is narrower than 525, hence having less weight as there's less material in the chain/sprockets. Note you need narrower 520 sprockets as well as the chain otherwise rapid wear of both will ensue.

For a given set of manufacturer's materials, in theory 520 will be weaker than 525 but on the SV it's unlikely to make a difference due to the relatively low power of the bike. Shoddy maintenance (cleaning/adjustment) will kill any chain more quickly.

If you buy decent stuff it's unlikely to be a problem, but I'm not sure you'd notice a real difference either. I wouldn't spend money to change until it was time to change a worn out chain/sprocket set anyway.

[embee]

First number is "eighths of an inch" pitch (distance between pin centres), second+third numbers is "eighths of an inch" sprocket thickness (nominally).

"520" means "5" eighths of an inch pitch, and "2.0" eighths of an inch sprocket thickness = 1/4" (nominally).
"525" is 5/8" pitch and "2.5" eighths thick = 5/16" nominally.

The strength comes in the sideplate and the shear of the pins, there is generally speaking no significant difference in either of these between 520/525. The big difference is in the wear area between the rollers and the sprockets.

520 is commonly used for racing purposes, I understand, and can be without the O-ring feature (= high maintenance).
525 "O-ring" is a better compromise for road use where wear/life is a significant factor.

Embee thanks for the clever answer to my simple question lol.

So just stick with the 525 is the best course of action then

Chain drives are very power sapping possibly one of the most inefficient forms of power transmission, by running a 520 chain yes less weight, gyroscopic effect and it also causes less drag you can free up a couple of ponies by running a well lubricated and ajusted chain most racers use 520 size chain us included.

Cheers for that gonna have a nosy and base it on price when I need to replace it I think

[mikerj]

Originally Posted by davegixer1300r

Chain drives are very power sapping possibly one of the most inefficient forms of power transmission,

Sorry but that's simply incorrect; a properly lubricated/adjusted roller chain is a very efficient form of mechanical power transmission. If you want to see poor efficiency look no further than a shaft drive, vastly worse than a chain.

[andrewsmith]

Unless your racing stick with 525 as they're more robust and will last longer