520 chain conversion

[Mickwitchy]

Hey guys,

Don't know too much about chains. I wanna get new sprockets (-1 and +2). Do I need to get a new chain as well or can I just use the stocker?

Bike has done about 4000 clicks.

And what is the 520 chain anyway?

Cheers,

Mick

[Blurr]

With that little kms you should be ok to just change sprockets. In saying that when stepping up at the back the sticker may not fit however you are dropping one at the front so all should be ok.

520 is referring to the pitch. Zx10's have a 525 pitch and the bigger 12 and maybe 14's (however not 100%) have 530.

Smaller pitch (skinnier chain) means less weight which turn into centrifugal weight when turning so meant to help handling. In saying that for road use 525's last longer generally

[Gosling1]

12's and 14's both run 530 pitch.

520 pitch better for 100% track use, but as Russ says - 525 will last longer for road use.

[Nosferatu]

If you go -1 +2 don't forget to get a SpeedoHealer, or you'll be getting overtaken by every blue rinse set on the road.

[Mickwitchy]

Thanks guys, might just get the sprockets at the moment

[BrettZZR]

Smaller chains/sprockets are lighter, and unsprung rotating mass is important if you are on the track.
They also will have a shorter life.

Some guff from the EK site:


And a quick terminology definition:


As a general rule, replace sprockets and chains together. Worn chains eat sprockets because even the slightest wear increases the pitch by a ball-hair. This means that fewer 'teeth' are pulling on the chain, eventually, only one and then the teeth actually start 'deforming'. Putting a new chain on a worn sprocket or vice-versa will result in the new becoming old rapidly.

If you want to split said ball-hairs, it is actually feasible to replace the chain only and extend the sprocket life to two ore maybe even three chains worth, but the crux is to replace the chain often enough. This is hard to predict as a modern O, X, Y, Z, blah chain has a long life followed by sudden and rapid wear. My understanding is that when one of the pins wear enough to stress the O (or X whatever) ring, and it fails to keep the lubricant in and starts rapid wear. This causes local heating and local stress. One worn pin delays taking load from the next and loads it up. So once it starts, the lubrication fails like pulling a zipper open (minds out of the gutter now guys!) If this has happened, the sprockets are more than likely buggered.

Bottom line is to be sure you catch it early enough, you need to replace the chain well early enough, and the cost saving is a bit offset by ditching a chain that just might have still had a fair life left?

[BrettZZR]

Oh, and before somebody points out that the wear life for the chains above is the same, those are the design life figures, at design load - which you could assume would be some fraction of the tensile strength.

(-8

[koyote]

Stick with std size and don't buy any cheap shit ---- you must be looking for extra grunt with that change in gearing. Have you seen the mess a chain makes . When it breaks @ ten grand in first gear it will take out the whole left side crankcase and some times the back of your leg

[koyote]

Stick with std size and don't buy any cheap shit ---- you must be looking for extra grunt with that change in gearing. Have you seen the mess a chain makes . When it breaks @ ten grand in first gear it will take out the whole left side crankcase and some times the back of your leg

[oldman]

Stick with std size and don't buy any cheap shit ---- you must be looking for extra grunt with that change in gearing. Have you seen the mess a chain makes . When it breaks @ ten grand in first gear it will take out the whole left side crankcase and some times the back of your leg

Which means stay away from Chinese shit. Their quality control sucks as they have none.
-1 +2 is quite a drop in gearing. You should calculate what the speeds in each gear will be. There is a formula for this and if your not a mathmatician somebody had a URL for a site that does it for you. Have a Jim, (Beam that is) and all will become clear.

[oldman]

Here's the formula.

Speed= RPMxFSTxTCM/PGRxGRxRSTx26,817

Speed in MPH
RPM=engine rpm
FST=front sprocket teeth, (16 or whatever)
TCM=tire circumference in mm, (about 1975 for 190-50/17)
/=divided by
PGR=primary gear ratio, (you will find this and the gear ratios in the service manual)
GR=gear ratio for the gear your in, (1st, 2nd, etc.)
RST=rear sprocket teeth, (42 or whatever)
26,817=conversion to MPH from metric mm of tire circumference
Pretty easy formula. Just use the value for tire circumference of 1975 and it will at least give you an idea of the amount of speed you will loose in each gear with your new ratios.
Just dropping one front tooth on my Z cut my top speed down 10 MPH.
Good luck and don't forget Jim, (Beam that is).

[BrettZZR]

Here's a much easier way:

X = (Fn/Fo) x (Ro/Rn)
F= front; old and new
R= rear; old and new

At the same revs:
Speed after = X x Speed before

At the same speed:
RPM after = RPM before / X

T'weezy...

(-8

[BrettZZR]

So your -1 +2 option applied to a ZZR (I don't know what your OE sprockets are) gives:

X = (16/17) x (45/47)
X = 0.9011

So at the same revs, speed would go from 100 to 90 <<< applies to km/h, mph, or if you ride a Harley, Furlongs per Eon
And at the same speed, RPM would go from say 4000 to 4439.

I made a quick tool {beware the bored engineer} with eXcel:
CLICK!
Then click <File> and then <Download>...

(-8

[Mickwitchy]

That's some very helpful info guys. Still haven't bought anything yet but I'll stay away from cheap stuff and hope for the best

[JimZXR]

Encase you're thinking of doing the conversion, SuperbikeSupply do a 520 conversion kit with whatever sprocket size you want for $250+delivery!

It's good stuff too; RK Chain and Vortex sprockets!

I used Renthal sprockets on mine but still have the altered gearing Vortex ones somewhere!