tyre profile and handling

[frankyknuckles]

in all of the performance tin tops I have owned there has always been a trend to fit larger wheels and lower profile tyres to improve the handling of the car and it seemed in most cases the upgrade was justified.

 

how does this apply to the 7? I get the impression that for road use (and track??) the common opinion seems to be that 13" rims with CR500 tyres produce better handling characteristics that 15" rims with CR500 tyres. (why else would the R500 have them?)

 

So, considering I am getting an R300, what are your opinions on 'road performance' wheel and tyre combinations?

 

go to the build diary section of Here

[Graeme Smith]

I think its to do with that a Seven is much lighter than a tintop, so saving (unsprung) weight with 13" wheels is more of a benefit than improved handling of 15" wheels.

[frankyknuckles]

so would a 13" rim be better for road driving (bumpy roads etc) and the difference between 15" and 13" on track is negligable?

 

go to the build diary section of Here

[Graham Sewell]

If that were the case, I would expect Caterham Cars to supply all road cars with 13" and track cars to have a variety. It seems that the opposite is true and has been said in the past to be because certain sectors of the car buying public cannot believe that a car can handle well on 13" wheels - hence they supply 15" wheels on some of the road going versions.

 

Low tech luddite - xflow and proud!

[martinwhitcher]

13" wheels are better because:

 

a) they are lighter.

 

b) un-sprung weight

 

c) cheaper tyres ie. yoko's from george polley 40-60 per corner 😬

 

GO FOR 13", YOU WILL NOT REGRET IT ❗

 

Martin

 

MW 51 CAT

Superlight No.171

[SteveP]

I have a set of both (also an R300), so feel as though I can comment. Firstly my 13" Minators with Bridgestone RE720, weigh about the same (although not measured) as my R300 15" rim with CR500 - if anything I'd say the 15" rim is lighter.

 

For the road, the 13" are more comfortable as there is quite a bit more profile (60) than the CR500 (45) - it is noticably more "bouncy" on the 13's

 

I run the 13" rims for sprints and personally, I don't like them as much as the 15" which I have also run at the same venue, but this might be down to the tyre more than anything - the car doesn't feel as planted on 13's as on 15's. The car seems to "squirm" around on the 13's which is most disconcerting.

 

Perhaps I'll change my mind if I get a set of 13's with some 21Rs or 32Rs or something, but right now I'm considering going the other way - list 1A on 15" rims instead.

 

The R300 rims also look fantastic (IMO only)

 

 

SteveP

[rgrigsby]

Generally 7's feel better with 13".. as a general rule of thumb, tyres make a huge difference so Bridgestone 720's vs Cr500's will give a big difference. CR500's are much much sticker.

 

This is all very suspension set-up dependant though!! a there is definetly an element of what you are used/personal preference.

 

Rob G

www.SpeedySeven.com

[eric]

Not far from the point of view of SteveP

 

O32 and 13" are bouncy

tramline some

send more stones than my road tyres

 

A539 in 195/50 15" better stability

better gearing too for touring

better comfort

 

So I keep 032 for circuit and the 15" for the road or the wet track

 

 

 

eric