Just for information:

I bought some renthal sprockets for a 428 chain, and compared the weight to the steel sprockets, wow!

Renthal front 18 tooth - 175g
Steel front 19 tooth - 220g

Renthal rear 47 tooth - 303g
Steel rear 45 tooth - 768g

Total saving with renthal sprockets 510 - over half a kilo.
The 428 chain is also approx 250g lighter than the equivalent 520 chain.

Obviously, the aluminium sprocket will wear quicker and the chain will wear quicker too. But thats quite a weight saving if you're racing.

If your racing then yes definately
For the road I'd say the best combination is alloy rear and steel front as the front has the drive and more pressure per tooth. this is generally whats supplied anyway.

Is it Stealth that do an alloy carrier with steel toothed rear ????

Sorry, I wasn't clear, it is a steel renthal front - just a little lighter. And an alloy rear - much lighter :)

hi, new here, just aqcuired fzr400 3tj year 1990, is the standard sprockets gearing 19 front and 45 rear? thanks in advance, any info/reply are much appreciated.