I am interested to see what people use on their cars with regards to spring rates and bike engined cars used for racing.

I understand we all have a different view on this but will be interesting to see

I will start my car has 275 rear with 300 front.

Those sound high. I'd be interested to know if thats common on race BECS.

Wasn't the original sugested rates 160f/130r for road use. I know there's been a general move towards higher rates (prob'as the motors have got more powerful). Mine are only road and trackday use but just for comparison, 210f/180r. I've recently swapped from 160 on the back mainly because I found when loaded with camping gear and on lumpy roads I hit the bump stops more often than I'd like.

yes they do seem high but have not driven the car yet. On my striker I also ran the same as you 210/180 and that was with a car engine in?

220F/180R

I was thinking of going to 250F/220R

You are far better off starting soft and stiffening it up slowly. Is it live axle? ? I dropped my fury rgb car down to 180 at the rear and then stiffened it to 200. Any more than that and yoh couldnt get power down at the rear. I had custom front wishbones and requirwd 350 at the front but that was a lot higher than standard. Id say you starting of far too high with those rates.

Thanks for the replays, the car has an independent rear end (for info). Looks like I have a few little jobs to do over the winter ready for next years sprinting.

If ypu want to make the front end of the fury more streamlined and generate some downforce I still have the mould for the front clam shell, basically its a nose that bokts onto a classic bonnet

When pondering the same question multiple RGB Champion and friend Tim Grey advised us "250 all round".

I hillclimb my mk3 striker and use 225 front with ARB and 180 rear with a live axle. It's to hard for rough roads but works well on the hills.

I ran 275/225 on my live axle plate LSD Striker Fireblade (420kgs - track day) nicely balanced in the dry but required aggression to overcome turn in understeer in the wet.

I'm starting with 250/180 with my open diff live axle Striker Zetec (track day only sub 550kgs - I hope).