Tyre and rim sizes

[Graham King]

Folks, am looking to buy a new set of tyres and was planning to go up to 205 R13 from the current 185 on the back. Doing a bit of searching most sites say these are too big for my current 6" rims but too small for 8" rims. As these are both the standard Caterham rim sizes and Yokos and Toyos are only available in these sizes others must be running on one of these combinations.

 

So do the 205's fit on the 6" rims, 8" rims, both or neither properly?

 

Thanks.

 

Graham.

[7 wonders of the world]

A 6" rim will happily seat a 185/60x13 on the front with an 8" taking a 205/60x13 at the rear

[Graham King]

Thanks 7wow, will the 205 sit on a 6" at the rear or does it require the 8". Wondering really if I need to buy 8" wheels at the moment or can use the 6" for a while?

[Gordon C]

Quoting 7 wonders of the world: 

A 6" rim will happily seat a 185/60x13 on the front with an 8" taking a 205/60x13 at the rear

 

Graham, the way i read that is..........

 

6" will happily take 185/60/13

&

8" will happily take 205/60/13

[Nick Chan]

I had a car with 205 tyres on 6" rims that fitted and drove fine

[skeetsy]

As with Nick, I had an Opel Manta which I ran on 205 60 13's on 6" rims and apart from them being Firestone's which were a right handful in the wet, they were fine.

 

I have 205 60 13's on my 8" rears and there is a little bit of tyre stretch, but it's nothing too extreme like some of the VW boy racers....

 

http://images25.fotosik.pl/129/7d3ee08d6c7bdcba.jpg

 

All the best

 

Richard

[6speedmanual]

Graham, what are your reasons to "upgrade" to wider?

Both myself and another R400 owner local have found "downgrade" rears to same as fronts to bring very satisfying results.

 

Peter

[Graham King]

Thanks for all the responses folks.

 

Nick, thanks for confirming that 205's will fit on 6" wheels

 

Peter, good question actually, for road I guess the real answer is aesthetics as I like the look of cars on 8" rears. I also do the occasional trackday and on track I do find the current 185's can be overwhelmed at times (I have 210BHP). What made you change back to 6" from 8"?

 

Graham.

[zetec]

Buy 7" rims like I did- looks good & tyre sits correct on the road

[6speedmanual]

Quoting Graham King: 

Thanks for all the responses folks.

 

Nick, thanks for confirming that 205's will fit on 6" wheels

 

Peter, good question actually, for road I guess the real answer is aesthetics as I like the look of cars on 8" rears. I also do the occasional trackday and on track I do find the current 185's can be overwhelmed at times (I have 210BHP). What made you change back to 6" from 8"?

 

Graham.

 

I retain the option of 8" / 205 on the rear. However for road and probably track too 175 or 185 alround gives better balance, adjustability, finesse, fun.

 

With the narrower tyres you can really feel the rear suspension working. One notable difference is it is easy to feel the effects of the outer rear tyre being overwhelmed by load transfer from the ARB.

Disconnect a drop link and the improved grip from the job being more fairly shared by both rear tyres is obvious. Note that with bigger rear tyres this load transfer is still taking place, so which is better? One fat tyre working hard and one lazy, or two both working nicely in range?

The transition point near breakaway is also slightly more predictable and has a wider 'transition' zone between gripping and sliding. Therefore it is more accessible and entertaining an area in which to play/drive.

One possible downside is that running narrow tyres at the rear significantly reduces their life to aboout 2/3 that of the front. With 175/205, they seem quite closely matched.

 

It's a really easy and cheap chassis mod which will access a huge change in feel.

 

If you go for the, erhemm, "upgrade", please detail back on this thread your findings and ARB adjustments you feel appropriate with the fatties on.

 

Note to BenF: Anything to add?

 

Peter