Good lord the OEM wheels are heavy!!

[CanyonChasers]

Like, you guys all said the wheels are heavy - but good lord!!! 5.4 kg WITHOUT the rotor!?!?! Thats 12 lbs in freedom units! For just the front wheel. Are these things cast-iron instead of cast aluminum or something?!?

For comparison, my 848 front wheel was 3.2 Kg's (7lbs)

 

[kostean]

I don't know from what alloy have they exactly poured these wheels out of, but they are indeed heavy as heck even when compared with some 1000cc wheels. Regulations at ssp300 classes usually restrict the use of any other wheels aside from OEM, but I am sure on the racing track, the set of lightweight wheels would make a very notable difference on 390.

 

[Formula390]

I don't know from what alloy have they exactly poured these wheels out of, but they are indeed heavy as heck even when compared with some 1000cc wheels. Regulations at ssp300 classes usually restrict the use of any other wheels aside from OEM, but I am sure on the racing track, the set of lightweight wheels would make a very notable difference on 390.

Lighter wheels do indeed make a huge difference. Setting up the suspension is a little more tricky, but doable. Heck even going with my 415 sprockets you can drop 4.2# in unsprung reciprocal mass. There's a LOT of power and seconds off lap times to be had from lighter wheels and a lighter chain and sprockets.

 

[Karfanatik]

Lighter wheels do indeed make a huge difference. Setting up the suspension is a little more tricky, but doable. Heck even going with my 415 sprockets you can drop 4.2# in unsprung reciprocal mass. There's a LOT of power and seconds off lap times to be had from lighter wheels and a lighter chain and sprockets.

In your opinion whats a good lightweight sprocket/chain combo? Can't quite afford the wheels yet

 

[Formula390]

In your opinion whats a good lightweight sprocket/chain combo? Can't quite afford the wheels yet

Well, I make 415 sprockets, and a DID ERZ chain is the way to go.

http://formula390.com/parts.pl?D=sprockets

That'll drop 4.2# of mass.

 

[Karfanatik]

Well, I make 415 sprockets, and a DID ERZ chain is the way to go.

http://formula390.com/parts.pl?D=sprockets

That'll drop 4.2# of mass.

I'm assuming with the different size of sprocket, the # of teeth will be different than stock 520 sprockets. Stock gearing for comparison, what # of teeth front/rear should we booking looking for when converting to 415 goodies?

 

[Formula390]

I'm assuming with the different size of sprocket, the # of teeth will be different than stock 520 sprockets. Stock gearing for comparison, what # of teeth front/rear should we booking looking for when converting to 415 goodies?

Yes, gearing number of teeth changes because the pitch changes for the sprocket teeth spacing between 520 (larger) to a 415's (smaller) pitch from tooth to tooth. A 520 15T front is approximately the same as a 19T 415. To maintain the same 15:45 ratio for 520 to a 415 setup you would run a 19:57. Most go with something like a 19:55 or 19:53 for racing setups tho. It all depends on your track and your HP output tho. Every track is going to have a different optimal gearing. I also make a 20T front, which is about the equivalent of a 16T front 520. The diameter of the sprocket is the same, it's just the difference in tooth pitch that requires the larger number of teeth.

I created a large spreadsheet that has a TON of information on it for gear ratios, top speed as well as a tab which has speeds per gear, chain length, et cetera. All the info you would need can be found on it at:
https://docs.google.com/spreadsheets/d/1T42Kjs53Xbad4d_krrIw5OPAEve9NntuLEwNRPkrnOY

Mind you, this spreadsheet is all math to get those answers. Things like clutch slip, wheel spin, what your specific rev limit is (for example if your ECU is flashed you can get higher RPM or if you enable overrev on a piggyback fueling module like a PCv or Rapidbike Evo), your bikes specific power delivery for peak HP and where you shift will move the numbers some, et cetera. It's a ballpark, a good one that I've put a LOT of work into, but it's just a ballpark. It's up to you to make the best gearing choice for your bike and your racing style. I created the gearing speadsheet just as a public service document to help people with making their gearing decisions.

 

[Karfanatik]

Yes, gearing number of teeth changes because the pitch changes for the sprocket teeth spacing between 520 (larger) to a 415's (smaller) pitch from tooth to tooth. A 520 15T front is approximately the same as a 19T 415. To maintain the same 15:45 ratio for 520 to a 415 setup you would run a 19:57. Most go with something like a 19:55 or 19:53 for racing setups tho. It all depends on your track and your HP output tho. Every track is going to have a different optimal gearing. I also make a 20T front, which is about the equivalent of a 16T front 520. The diameter of the sprocket is the same, it's just the difference in tooth pitch that requires the larger number of teeth.

I created a large spreadsheet that has a TON of information on it for gear ratios, top speed as well as a tab which has speeds per gear, chain length, et cetera. All the info you would need can be found on it at:
https://docs.google.com/spreadsheets/d/1T42Kjs53Xbad4d_krrIw5OPAEve9NntuLEwNRPkrnOY

Mind you, this spreadsheet is all math to get those answers. Things like clutch slip, wheel spin, what your specific rev limit is (for example if your ECU is flashed you can get higher RPM or if you enable overrev on a piggyback fueling module like a PCv or Rapidbike Evo), your bikes specific power delivery for peak HP and where you shift will move the numbers some, et cetera. It's a ballpark, a good one that I've put a LOT of work into, but it's just a ballpark. It's up to you to make the best gearing choice for your bike and your racing style. I created the gearing speadsheet just as a public service document to help people with making their gearing decisions.

I knew I saw this spreadsheet somewhere. Appreciate the info and have some fun stuff to mull over now