Which 520 rear sprocket?

Hi all,

I ordered a 520 conversion kit with a steel 16T front sprocket, DID520erv3 and an extra hard coated aluminium Vortex rear sprocket.
Yesterday I received an email that Vortex doesn't make the extra hard coated sprockets anymore but I could get the Vortex Cat5 sprocket (ugly!) instead since it's the same price, they don't offer a different 520 40T rear sprocket for the SD.
Does anyone know how the Cat5 sprockets hold up compared to the PTFE coated ones or even better, know a company who delivers a good quality aluminium or lightweight steel rear sprocket?

Also, is there anyone who can confirm the SD and RC8 rear sprockets are the same? This would make my search easier since there are a lot more sprockets for the RC8 available.

Yep they are the same ...I fitted my mates RC8 back sprocket to my SD


......why are you going for 520....unless you are racing?

Looks like an Aprillia (RSV4 etc) sprocket has the same dimensions as the KTM's, there are more sprockets available for those but I'd like some confirmation on that one too if someone could give me that.

Wieres in Germany

They hold up nearly like a steel chainwheel when greased properly

Power wont stretch a chain, only bad adjustment. The DID ERV3 is a superbike spec chain. A superduke is only tickling it. The GP1 guys with 200bph are using ERV's for over a season with barely any stretching.

RC8 rears fit. Or you can just get your sprocket supplier to machine a 525. Talon make rears pretty quicky and you can spec any colous you want.

Thanks for the replies, I've contacted the Supersprox importer over here and he needed the sprocket sizes because there wasn't a 520 sprocket in their system. Hopefully they'll be able to supply one for around 60 euros because one sprocket would probably outlast the chain.

For anyone on SD.net searching for the measurements, check this link:
http://www.wieres.de/Shop/1790-40-AU

I use a 520 + Vortex aluminium sprocket on my '05 GSXR1K track bike. No issues. Saved a ton of weight. Just bought a 520 for my SD.