I think Rob has a set of the RenaultSport 16" alloys. I see they're a little heavier but am interested to know:
- What size tyres would have been orignally used with them / recomended - is the final result the same rolling radius?
- Is the weight of wheel + similar tyre less than using original 15" Wheels?
- How is the ride affected - Is there decreased 'feel' as with using 195/50/15 instead of 185/55/15?
Looking forward to a reply, probably from Rob
I believe the Renaultsport 16 inch wheels used on tarmac used 195 50 16 tyres. This would give a rolling circumference of
1889.35 mm. The 15 inch williams wheels with 195 55 15 tyres has a rolling circumference of
1836.26 mm. Swap that to a 195 50 15 tyre and the circumference is
1809.56 mm. If they used a 195 45 16 tyre then the circumference would be
1828.09 mm.
So in reality the 16 inch tarmac wheel is probably halfway between standard 185 tyre an the 195 50 15 tyre in rolling circumference.
Weight wise, the 16 inch wheel is 8.9 kg, new with paint. A williams wheel is 7.2 kgs new with paint. I would suspect that the tyres are similar in weight. However, different brands of tyre do have weights that vary considerably. I have weighed a brand new Michelin Pilot PE2 and a brand new Kleber Dynaxer HP2 and there was a kg difference in weight per tyre. Therefore you could probably get the weight of the 16s to the same weight as the standard 15 inch wheels if you got the right tyre combination.
From another view though, you might want to look at the width of the tyres. People on other forums seem obsessed with fitting wide tyres, because they think it increases contact patch and therefore grip. I dont agree with this, as the contact patch relates to car weight (pressure), not tyre width. If the car weight stays the same the contact patch chages shape, but does not increase. More importantly however, Renault decied not to fit a wide tyre to their 7.25 inch super wide 16 inch rim, and instead fitted a narrow tyre. My guess is that they wanted to stretch the sidewall, just as the 7 inch wide williams wheels stretches the sidewall of the 185 tyre (something the 195 tyre will not be as greatly subjected to). This would have the effect of increasing sidewall rigidity. Ive driven a clio on 205 tyres on a 15x7 rim and they are aweful. The tyre moves around on the wheel and the car feels very wollowy.
As for the ride, turn in should be sharper if the sidewall flex is reduced. I would say comfort wont be too affected because we know the williams is a peach over bumps of its thin tyre wide wheel combo. Maybe Renault knew that power is only good if the tyre is in contact with the road. What do you think? Or maybe it was a lucky guess
