Which tyre profile?

Diagro · 13 Oct 2015 at 23:25

Hey

So i have sourced some RX8 Alloys for cheap.
Being 18" i cannot reuse my tyres, which tbh is good as they suck.

I fancy some Rainsport 3's. I used these before on my old car and loved them, perfect for our weather and I felt safe.

But I am unsure which profile to match with the alloys.

They do 225/45/18, also 225/40/18.
I know the 45 profile would give a better ride quality, but by how much? and is it worth the extra outlay.

See the below for a price on them. Its £90 cheaper to get the 225/40/18! Smashing price of £54 each.

In my view, these tyres fit the bill, and are what i am after. I want a tyre that performs the best in the wet and still give very good grip in the dry. from my own experience and many others i can say that they do indeed fulfil that.
So No "them crap tyres there, here buy these at £100 a tyre!"

Havana_UK · 13 Oct 2015 at 23:35

It depends on what the stock tyres are, as you'll need to maintain as close a rolling radius as possible or it will affect gearing & speedo accuracy. What's the stock tyre/wheel size?

bJN · 13 Oct 2015 at 23:39

Just a pointer as to why there is such a big difference in price - you have two different load/speed ratings there, which will probably affect the tyre make-up slightly.

As for what size, I'd just stick with whatever is recommended for the RX8 alloys from actual RX8 owners, which I think is 225,45,18.

Havana_UK · 13 Oct 2015 at 23:54

So, just a quick look on Google suggest that your standard wheels & tyres and 205/50/17. If this is the case, then you should choose the 225/40/18, as your rolling radius and tyre circumference will be unchanged.

Diagro · 13 Oct 2015 at 23:57

Havana_UK said:
So, just a quick look on Google suggest that your standard wheels & tyres and 205/50/17. If this is the case, then you should choose the 225/40/18, as your rolling radius and tyre circumference will be unchanged.

Oh I see.
Intresting, looking like 225/40 then.
Lucky for me they are cheaper

Thanks all!

red eye · 14 Oct 2015 at 08:14

Roughly for each size up up in dia or width drop a size in profile
For a more accurate there are calculators on the web just google tyre size calculator

robj20 · 14 Oct 2015 at 08:31

Pretty sure the standard alloy was 18" and a 225/45/18 was fitted. Its what both of mine had.

Diagro · 14 Oct 2015 at 08:41

robj20 said:
Pretty sure the standard alloy was 18" and a 225/45/18 was fitted. Its what both of mine had.

Mine is on 17" alloys. 205/50/17. Just checked.

Just placed the tyres in the basket for the 225/40/18's

Now i just need to collect the RX8 alloys and get them Powdercoated over in Brum