Dirtbike for Motard with road bike tyres for Bucket track - Road tyres for 450exc

[omamari]

I have difficulty fitting in.

So I've got my 2007 KTM 450exc, which I barely ride dirt as Auckland is rubbish. So I thought I'd chuck on some road tyres. This way I can use it on the practice days of Bucket racing (and the occasional commute and thrash). Bucket track doesn't don't allow knobblies. So I want road tyres, but the main reason I was running knobblies was so I didn't have to fork out $1000+ and get a cush hub. My reasoning being the knobblies don't allow enough traction to be hard on the gear box. So 2 questions:

1. Running pure road tyres dangerous to my gearbox?

2. What the hell tyres are there? The adventure/dual tyres all seem to be focused at high capacity bikes. Currently I have dirt 140/80-18 and 90/90-21. Will any old road tyre design of these dimensions be OK to run?

I.e front http://www.motoone.co.nz/pirelli-90-90-21-scorpion-trail-54h-tyre-tyd2109090trail
Rear (150 may be a bit wide) but the gist is... http://www.motoone.co.nz/parts/tyres-558/dual-purpose-600/continental-150-70r18-70v-tl-contitrailattack-tyres-c1815070cta?sort=p.price&order=ASC&limit=100

Thanks!

[omamari]

Maybe cush is just not necessary...

http://motostrano.blogspot.com.au/2009/08/cush-drives-and-supermoto-wheels.html

...or they are all racers and often rebuild their bikes.

[mattsdakar]

Hunt down a set of road wheels for your exc to supermoto it.
I bought RGV250 wheels off trademe for $50 and $80...got some spacers machined and bob your uncle!
Have used them on a DR350, DRZ400, KTM 520exc, XR650R and now my current WR450
Bike handles fantastically, wheels pretty much fit straight in and comes with a crush drive

[clint640]

If you want some road tyres in 18" & 21" sizes I've found Bridgestone BT45's ok. Got a set on the shelf I spoon on every now & then for a track day. Reasonably priced, not $$$ sport rubber sticky but good for a thrash - you get a bit of feedback before they let go.

Cheers
Clint