Megane RS 18" vs Clio 197 17"
- Thread starter Happytart
- Start date
but you will be paying extra for bigger tyres when they wear out, if you move up to 18's, and you will loose some speed too
It stands to reason that if you change the rolling radius of your wheels and tyres, and the speedometer no longer reads correctly, that your odometer will also gradually become inaccurate. The car has to work harder with a larger diameter tyre/ wheel to accelerate at the same
Not that I know much about stuff like this but the people that have 18" wheels on here they run 215/40/18 instead of 215/45/17 which is basically the same radius? Is that correct?
Heavier wheels mean more unsprung weight whichwont help handling. I was going to buy r26r wheels then decided to go for something lighter instead
And the heavier the rim/wheel combo is the more mass moment of inertia it has (hope this is right since it is very hard to find technical expressions in normal dictionaries). The wheel form and with that the placement/distribution of mass can have effects to - the more mass is further away from the rotating axis the more mass moment of inertia it has.
The best way to demonstrate what I mean it this -the jumpers minimize their MMOI so they can spin faster - like this
Raptor6767
Gold Member
0,2-0,3s @ 1/4 mile.
I'm glad you answered that haha, I can live with that figure. I've been running 225/35/18's all round but after seeing a few others with 225/40/18 that'll be my next choice. I've decided to counteract the reduction in pace with a supercharger, hopefully I wont slow down too much.
i have 18 on and they are -1.6% smaller in diameter - therefore the gearing is actually lower - which equals faster acceleration - you could argue lower top speed - but against the wind you can maintain speed better due to lower gearing
as for the speedo "gradually" losing/gaining accuracy it will be immediate !
just one point to ponder !!!
a new tyre has 8mm of tread on it - when worn to the uk minimum it has 1.6mm left - the tyre has reduced in diameter by 6.4mm.......
as for sprung/unsprung mass - whilst true - in the real world will you really notice - its a road car not a fia homologated racing car :thumbup1:
Won't that be double though? As its a circle... You've just done that calculation for a single point on the tyre...what about the point on the opposite side of the tyre...?
and thats why the cup racers, have smaller wheels, like the old 1*2 they put 15" wheels on for the track, as its better for speed and accelleration. but as your only after looks then go for it.
your not driving on that bit
my point was that the tyre diameter changes with wear to begin with - not only that the 18 i have are only 5mm in diameter smaller than normal
new 17 tyres ..............or the difference is so small not to make a noticeable difference
