520 chain conversion

[speedracer170]

So what is the average weight savings by switching from a 525 to a 520 chain setup? I did my swap tonight and saved about 2.28lbs including the light weight rotor swap, only 1.31lbs of saving if you just count the chain setup. just seems really low without including the rotor

Stock 525 setup weight:
Chain 114 links 65.4oz
F. sprocket 7.7oz
R. sprcoket 25oz
R. rotor 28oz

Vortex 15T sprocket 5.9oz
Driven 14T sprocket 5.7oz

520 setup weight
DID EVR3 520 chain 114 links 61.7oz
Vortex 45T sprocket 12.1oz
Vortex 14T sprocket 4.9oz
Lightweight R rotor 15.5oz

[blendedfamily]

1.3 pounds ain't bad at all though.. just because you're not dropping double digits dont mean it ain't gonna help. less rotating mass!

(I really have no idea what I'm talking about, but I've heard someone smarter than me use those words before)

[kz2zx]

Quick lesson in physics...

Force = mass x acceleration. This is straight-line motion

The equivalent in a rotating system - planet Earth rotates, for example, and so does a motorcycle wheel - is

Torque = Moment of Inertia x Rotational Acceleration

or Τ = I·α

α (alpha) is measured in degrees per second per second (or radians·s^2)

I (inertia moment) is the interesting term here. It's really the static (resting) mass of the object (wheel plus sprocket and the portion of the chain on the sprocket), times the magnitude of the square of the distance from the center of the axle to the center of the distributed mass of the rotating object.

Huh?

The more mass (heavier) the sprocket is, and the bigger the ring of the sprocket, means more mass rotating a distance away from the center of the axle. Thus the same torque from the engine has to work harder to move that mass (think of it having a lever effect working against you, not for you). Two sprockets weighing the same, but one's (thinner and) has more teeth, the larger-diameter one will take more torque to spin up to a speed.

Help or not?

[findgold]

And in the whole world.Only a very few racers, will this info and change be of any use/help..

It never hurts to remove a few pounds from your bike and rider..Or add a couple more hp.

But in the long run If you are only using 90 precent of what can be done with what you have in your bike. How much will adding more to your bike help?

Perhaps its a mind thing. You have improved your bike a little. will you still be getting 90 percent and going faster?
or just have a better/faster bike that now you can only use 88 percent of?

In other words.

More important then bike setup (horsepower and preparation) Is rider skill, to know your bike and to be at home with its strengths and shortcomings, to be able to adapt to what your bike has to offer as a race bike, and for the rider to be able to meld with his bike.

[kz2zx]

Hrm...

520 chain is easier to work with (cut, rivet). Aluminum sprockets really do make a difference over OE steel. If you're going to regear - which even some Ninjette racers do (down to 428 chain?) - it's easiest and cheapest to go with 520 over OE 525 or 530.

[findgold]

The 428 ninjette sprockets for the ninjette are hard to come by. Even getting 520 rear sprockets have to be speciai ordered for most sizes.. I have found a few 428 sprockets that will fit the ninjette but not with the tooth count that will work for either NM track. and I have all the 520 sizes that come close..One tooth on the rear can make a big difference on the ninjette.. Tho not having any top end speed is the big problem down at Arroyo' having to race LW classes with 650's
And back in the old days the Yamaha FZR400 came with 428 chain and sprockets. But everyone went to 520 for racing..

[chefboyartie]

I kind of wish all that didn't make sense.

[speedracer170]

I was just curious if anyone else knew the before and after weight of their conversion.

[findgold]

I was just curious if anyone else knew the before and after weight of their conversion.

BOY!

just look at what you started..

life, it tuff, between race weekends.

Way back in the old days you would be amazed at the trouble/expence people would go to, to remove weight from their tz250/350 brake rotors..They were very heavy..