The unsprung mass of a wheel offers a trade-off between a wheel's bump-following ability and its vibration isolation. Bumps and surface imperfections in the road cause tire compression, inducing a force on the unsprung mass. The unsprung mass then reacts to this force with movement of its own. The motion amplitude for short bumps is inversely proportional to the weight. A lighter wheel which readily rebounds from road bumps will have more grip and more constant grip when tracking over an imperfect road. For this reason, lighter wheels are sought especially for high-performance applications. However, the lighter wheel will soak up less vibration. The irregularities of the road surface will transfer to the cabin through the suspension and hence ride quality and road noise are worse. For longer bumps that the wheels follow, greater unsprung mass causes more energy to be absorbed by the wheels and makes the ride worse.

 

Sprung weight is the mass of those parts supported by the suspension.

Unsprung is the rest; wheels, tyres, brakes, chain etc. Changing the unsprung weight has no direct effect on springing (as it's not supported) but reducing it can make a big difference to the ease with which a bike can change direction.

For example, lighter wheels produce smaller gyroscopic forces.

Lighter tires, tubes, rotors, hubs, spokes, rims and sprockets reduce the gyroscopic effect of the spinning wheels. With less gyro, the bike steers lighter, handles better and accelerates harder. This is something that even the most oblivious test rider can feel.

If you are interested in reducing unsprung weight, you should know that some kinds of unsprung weight are worse than others. For example, the further away from the swingarm pivot the weight is located, the faster and farther it moves and the quicker it’s forced to change direction. You need to concentrate on lessening unsprung weight that is at the furthest end of the fulcrum arm. Conversely, the closer the weight is to the swingarm pivot, the less it affects suspension performance.

When you put your bike on a weight-reduction plan, it is important that you remember the 6-to-1 rule. It is said that a 1 kilo reduction in unsprung weight is equal to a 6 kilo reduction in sprung weight. Thus, if you’re going to spend money on lightweight hardware, concentrate on unsprung weight.

 

The zx7r wheels are heavy! You can buy aftermarkter wheels but they are expensive and hard to find.

An easy ad cheap mod is to get a zx6r wheel form the G/J series (98-00 or 00-02).

they have the same axle size en rotor offset.

You will lose your speedo!

 

zx7r wheel: 5,3 kg (wheel incl bearings)

zx6r wheel: 4,5 kg (wheel incl bearings)

That's an easy 0,8 kg reduced!

 

To make them fit, U will need other spacers.

You can buy them here:

https://www.projection-components.co.uk/zx6r-gj-front-wheel-spacers-for-zx7r-front-end-124-p.asp

zx7r spacers en speedo pick up: 255gr

zx6r alu wheels spacers: 55gr

That's another 200gr reduced

Total: 1 kilo!

 

You also get rid of the speedo cable wich is 200 gr but that is not unsprung weight...

 

You want to reduce more?

Replace the OEM breakdisc with aftermarket ones

OEM disc: 1,8 kilo

...... : ..... kilo

Less weight en more braking power!

 

Bolt these disc on your zx6r wheel with titanium bolts and you save another 80gr

 

Titanium bolts: 70gr (10 pieces)

OEM bolts: 150 gr (10 pieces)

 

Keep in mind that you can save some extra weight with the 4 pot mod

Nissin 4 pot brake caliper: 950gr each

Brake pads:  CL: 219 gr per set

 

 

zx6r spacers in alu: 55gr per set

zx7r spacer en speedo pick up: 255gr

speedo kabel: 201gr

 

 

 

 

 

 

 

zx6r j model, zzr600 (05-08) zx9r (00- 03) have the same front wheel.

98-99 zx9r uses a 20mm axle! stay away from that year

96-03 zx7r uses a 25mm front and rear axle

 

02-03 zx9r uses 320mm rotors like the 96-03 zx7r.

they bolt right on