Gramas

Going to buy new alloys for me classic sport cant decide if i should get 17" or 18" wheels, what would sit best? dont want to have to alter anything so please advise me on what size & best fitment so dont rub or catch.

alcazar

iTrader: (2)

Either will fit with the right offset, and the right tyres, plus if you use a tyre size calculator, the speedo will read fairly accurately.

However, 17" wheels offer the best for ride, comfort and handling on a classic.

Mine rides on 17" WRX bronze wheels, with 215/40 17" Toyos Proxes T1R.

GMballistic

iTrader: (1)

I've got 17"s on my classic WRX which are perfect IMO.....with plenty of room to lower oneday too. My mate also has 17"s on his Type RA but he's eager to move upto 18"s now as he has just fitted AP Racing calipers all round (4 pot rear & 6 pot front I believe) and there too tight with 17"s near the caliper especially on the fronts. Might want to bare that in mind.
And as alcazar has mentioned you will also want to look at a tyre size calculator so that you don't mess your speed reading up too much, but I believe for 17" wheels you will need 215/40/17 tires to keep it reading accurately (as he has on his & me too )

Gramas

so 215/45/17 are not as good?

moro

iTrader: (1)

Original tire size for UK turbo is 205/50 16" which is 611mm in diameter. Closest sizes for 17" are:
215/45 - 625mm (+2.29% speedo error)
215/40 - 604mm (-1.15% speedo error)
225/40 - 612mm (+0.16% speedo error)

Note that running bigger total wheel diameter is the same as running longer gearing in gearbox, it hurts acceleration. So I vouch for 215/40.

To run 18 you will need to fit ultra-low profile tires which won't be good for comfort and handling on b-roads.

Gramas

Cheers thanks

GMballistic

iTrader: (1)

They would work fine. That's the tyre size my mate has on his car and he has not had any probs. Basically from what I gather this is how it works;

Original tyre size: 205/50/16
New upgraded tyre size: 215/40/17

With this set up your speedometer would read a small percentage under the dials reading. In other words when your speedometer states you are doing 60mph you will actually be doing 59mph.

If you increase the profile to 45 then because it is ony a small size difference the speedometer will still read a percentage off but nowhere near as bad as if you went upto say a 55 or similar. As another example with the 45 profile your speedometer reading 60mph then your actual speed may be more like 61mph. Heres a few tyre size calculators for you bud;

Tire size calculator

TYRESAVE: Tyre Size Calculator

http://www.kouki.co.uk/utilities/vis...ize-calculator

Gareth

moro

iTrader: (1)

With bigger wheels speedo will show lower speed.
Let's assume it's calibrated for, say, 100 wheel rpms = 60 mph. Bigger wheels will make less rotations to cover the same distance, so now at the same 60 mph they will make only 95 rpms and speedometer will read lower.
Bigger wheels = speedo reads lower than actual speed is and vice versa

GMballistic

iTrader: (1)

Yes I think
But what people need to remember though is the rotational size of the original tyre on the car unless I'm wrong. My classic used to have a 205/50/16 (rolling radius of 611mm) so when I put a 215/40/17 (rolling radius of 604mm) on the car although the rim is larger, the profile is less and the entire rolling radius is very similar with only a small negative percentage difference (-1.15%) in the entire rolling radius of the tyre (hence why the speedo says 60 but I'm actually only doing 59).

I've been recommended; ±2.5% is the MAXIMUM difference in diameters

moro

iTrader: (1)

By bigger wheels I was actually thinking the total diameter, sorry for not being precise enough
So we're talking the same thing with different words

BTW you can install some 205/45 15" wheels, car will pull like a rocket. Short transmission ghetto-style

GMballistic

iTrader: (1)

Yes
I'm liking the Ghetto-style idea Could be good on the drag strips if I ever do that