JPSC Forum

Its been about a year now since I purchased some used 888's from Jeff and they got me through last years motoring as planned. They have a few miles left in them (or one track day at the most) but I want to get a new set in a month or two to replace them as I really like them. I also want to replace my now dated wheels (revolution 4 spokes) with something a little more modern and it makes sense to do it at the same time

I really want to stick to a 6x13 wheel (any bigger will stick out at the rear) which counts out 99% of what is being made these days. However I can get Caterham 8 spokes of Compomotive CXR in the right size....both of which I quite like

As I am a tight a**e I am now looking for an 'economic' set of Caterham 8 spokes. Only set I can find come with Avon CR500 tyres and the seller doesn't want to sell the rims separately. Am I right in thinking the CR500 will not be as good as the 888 in dry road and track driving? Can't see much of a second hand value in the CR500 tyres which says a lot if I want to get them and sell them straight on!

I have used both and last year sprinted with the CR500s. Fantastic wet and dry (use correct pressure)came second in the championship. 888s are about the same as far as I am concerned.

Just found out they are 175/55/13 and my current tyres are 185/60/13. Not much difference but it will knock 6-7mph off my top speed at Brands Hatch which is already slow

Yet more food for thought.

You need to actually at the rolling circumference on the manufactures website. Avon tyres always are larger than they say on the label....my ZZR 215/50 13 are closer to 230 section.

http://www.toyo.co.uk/tire/pattern/proxes-r888

http://www.avonmotorsport.com/road-lega ... ance/cr500

jeffw wrote:You need to actually at the rolling circumference on the manufactures website. Avon tyres always are larger than they say on the label....my ZZR 215/50 13 are closer to 230 section.

http://www.toyo.co.uk/tire/pattern/proxes-r888

http://www.avonmotorsport.com/road-lega ... ance/cr500

Even using the figures on the manufactures website it still reduces my top speed from circa 114mph to 109mph....I have plans to improve my top speed (new cams sitting on the shelf give me a little more power but more importantly 1k higher up the rev range ) but that is still 12 months away as I don't have time to rebuild the engine just yet. Can I live with the lower speed until I wear these tyres out?????

CR500s are quite expensive. What rev limit have you got on the engine? I'm not even sure I know what engine you have.

My car has a 2lt Fiat Twin Cam on twin 40DCOE. Safe to 7,250rpm with my current pistons and flywheel but then with my current cams power drops off after 5,700rpm so I am fighting a losing battle after that

I have some Abarth aftermarket cams on the shelf (rare as rocking horse poo), can't remember the exact profile off the top of my head but the peak power is about 1,000rpm higher than my current engine

Are you hitting the limiter at Brands then?

jeffw wrote:Are you hitting the limiter at Brands then?

No, currently don't have one fitted but it won't go much past 6,000rpm unless you find a very step and long hill!

With the new cam I get a) 20% more power and b) peak power is at 6,750rpm. Theoretical maximum speed is then 129mph with the toyos But as we all no the Striker has the aerodynamics of a house brick so not sure it could ever hit that without more power which I don't want (gearbox, axle, diff, axle links etc then all become weak points)

I wouldn't worry too much about the CR500 sizes then....At Brand Indy you will be lucky to see 100-110 mph with that much power.