Approved Rim Width Range for 15" 888's

[Space Cadet]

I was just on the Toyo site as considering running slightly larger 205/50/15's next rather than the OEM 195/50/15's.

The sizes & specification chart has a column marked "Approved Rim Width Range" with a minimum - ideal - maximum recommended rim width for each size of tyre.

For example, for the 195/50/15 it says 5.5 - 6 - 7 (6 being the ideal width).

Most of the Clio spec 15" wheels are 7" wide, the chart recommends a 215/50/15 is used for this width of rim: 6 - 7 - 7.5.

I know some on here recommend running the 205/50/15's but even these are recommended for a 6.5" rim: 5.5 - 6.5 - 7.5.

Bearing in mind I only really use the car on the track and that for the odd few road miles the speedo will be slightly out (an overall rolling diameter increase of 5mm), is it worth running 215/50/15's as they're 'only' 10m wider, i.e 5mm each side?
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Also, definitely considering running the harder, (is it GGG?) compound, has anyone tried these?
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[NorthloopCup]

Well considering all the racers on here now run 205's as they give extra noticeable grip, I'd say yeah it's well worth a shot with the 215/50's. the only issue you may encounter is on the rear. You will probably find you need to roll the rear arch lips or run smaller spacers (assuming you have them?)
I run 205's on a 6.5j wide rim and this is the issue I've encountered.

Can't comment on the other compound though.

 

[MG cup]

215/50/15 tyres will be bigger in every dimension compared to 205/45/16 which are well known to scrub anyway with anything more than a circa 25mm drop.

You would need the perfect offset wheel in combination with chopped/rolled arches to make that work. Iirc some of the racers still use 195 rears and 205 fronts due to scrubbing.

 

[Space Cadet]

Thanks guys.

Clearance isn't a problem I think as I've chopped the outer front arches and I don't have any inner plastic arches anymore so shouldn't be a problem there, the rears will soon be rolled anyway (don't think this will give more than 5-10mm) but could always remove or reduce the 15mm spacer.

The overall rolling diameter will only be 5mm greater so not really a problem there, I made a typo though in that the 215's would be 10mm wider each side, which as above might mean reducing the size of my spacers.

The question really was that as Toyo recommend to run a 215 tyre on a 7" rim is it therefore worth running a wider 215 or even just a 205 over the 195?​

 

[Chip-mk1]

As far as I am aware the most commonly available GG compound is the hardest and the GGG and SG compounds are both softer.

Ive found the OZ F1 seem to work well with a 205 tyre, I havent tried with a 215 though so cant comment on that.

 

[Space Cadet]

​Thanks Chip. I'm sure I'm running GG's, which are classed as Medium therefore I presumed there must be a Hard compound available. Although its not clear from what I can tell from a quick surf on t'net, like you say, the Medium's are actually the hardest compound, GGG is the Medium-Soft compound and then SG is the Super-Soft compound for hill-climbs etc.

End of that idea then!

Will have a think about the wider tires though.........

 

[Chip-mk1]

​Thanks Chip. I'm sure I'm running GG's, which are classed as Medium therefore I presumed there must be a Hard compound available. Although its not clear from what I can tell from a quick surf on t'net, like you say, the Medium's are actually the hardest compound, GGG is the Medium-Soft compound and then SG is the Super-Soft compound for hill-climbs etc.

End of that idea then!

Will have a think about the wider tires though.........

If you want firmer, buy RSR instead, they are cheaper too.

 

[Space Cadet]

​I am tempted to try another make, if only for a temporary comparison and I end up back with the 888's.

Am really happy with them in all conditions and the are just such a great tyre other than their wear rate and that they go off after about 15-22 minutes.


The same tyre but in a slightly harder compound would be perfect for me.

 

[Chip-mk1]

The same tyre but in a slightly harder compound would be perfect for me.

Slightly harder compound will mean less grip of course.

Which means the 888 would then just end up like the RSR anyway, lol.

If you are going to be dissapointed with less grip then dont waste your money trying anything harder.

 

[Space Cadet]

Thanks Chip, ok, wise words. I guess the less grip from a harder compound might be offset by the wider tire if i go down that route.

 

[Chip-mk1]

Thanks Chip, ok, wise words. I guess the less grip from a harder compound might be offset by the wider tire if i go down that route.

Actually you might find that makes it worse, you need to think about the co-efficient of friction compared to the weight on the tyre and the width of the tyre.

If you go for a harder tyre, you need more weight on it to work it hard enough, so if you go for a harder compound you might find you end up just sliding around with it not gripping.

Its about about finding the right combination its not a case of always wider=better

 

[Space Cadet]

​Hummm, ok, then perhaps same compound 888 but the wider 205 or 215 would provide the same grip but less wear??!!

 

[Chip-mk1]

​Hummm, ok, then perhaps same compound 888 but the wider 205 or 215 would provide the same grip but less wear??!!

If you are getting the tyre "go off" due to excess heat, it will probably provide more grip and longer life if you go wider.

 

[Space Cadet]

​Thanks Chip - that's sorted then, will stay with the 888's which I love but try a larger size next time. Thanks again, Mark.