Hello folks

ive got a set of slicks on my BEC. The rears are 200/550/13 and fronts 160/515/13. Im looking for a cheap set of used slicks but keep seeing sizes in the format of eg 7.0/20/13, Ive never seen that format before

Based on my tyre dimensions what can i fit on my rims and how do i decipher the 7.0/20/13?

N1

Multiply the first two numbers by 25.4?

As above one in inches, other in mm, width, diameter, rim size

So mine are 7.8/6.4/13 and 6.2/20/13

I know the R13 cant be changed, but can i change the width/aspect ratio?

Hi dont get your cross plys and radials mixed up

Your slicks are more than likely radials. Cross-plys tend to be measure in Imperial.

A 200 section radial is probably comparable in width to a 8.5 or 9" crossply. A 160 section is about the same as a 7" crossply.

You'd probably be looking at a 7.0/20 13 front and an 8.0/22 13 rear (or a 9.0 if you're running any more than about 200bhp).

[Edited on 24-7-12 by phelpsa]

according to Avon, crossply tyres are quoted as above, Radials are in the format we usually use.

i asked them what 8.5-23.5-15 relates to, the best they could tell me was go to a tyre shop and try a few on trial and error... really not sure why they couldn't just tell me, "yeah, 225/5-r15 should be very close" or something,
no idea if that is that close really, i'll need to work it out eventually

but its width in inches, OVERALL DIAMETER in inches (rather that 50% aspect ratio type thing), then rim diameter

Hi 7 inchs in width 20 diamiter of tyre 13 inch rim avons come in 19 /20/21/and22 we use them to change gearing for differnt hills

Hmmm...not as straight forward as i thought! Does anyone know the best place to get a set of scrubs?

remember the width is the tread width on slicks and on road cars it is the section width. Have a look at the 13" tyre sizes on the Avon Motosport website and compare radial slicks with Avon ZZR or CR500.

So will there be any issues with me having 160/535/13 on the front rather than 160/515/13?

Unless you change the ride height you will drop the front 10mm lower. Your front/rear geometry will change and hence the way the car handles - maybe better maybe worse. If you adjust the ride height back to what it was then you will alter the geometry.