Wheel Offset & Rim Widths (Please Help)

[RBOOLL99]

Hi all,

I currently own a Clio rs200 RB7 that comes standard with the "interlagos" 18inch rims and I am running 225/18/40 tyres. Seeing as most Clios came standard with 17inch rims I'm unsure whether the standard offset figures still apply? Could anyone please let me know what 18inch rims I can run and what width & offsets would be suitable.

Thanks in advance

 

[tomislavp4]

You still run standard width so the standard offset still applies.

 

[NickD]

Hi all,

I currently own a Clio rs200 RB7 that comes standard with the "interlagos" 18inch rims and I am running 225/18/40 tyres. Seeing as most Clios came standard with 17inch rims I'm unsure whether the standard offset figures still apply? Could anyone please let me know what 18inch rims I can run and what width & offsets would be suitable.

Thanks in advance

Assuming everything was the same, your standard offset would be 68mm. The lowest offset recommendation for a 7.5" wheel is 45mm. Given that your wheels are probably 8" wide that would bring that back to 58, although the official recommendation is 54 given that your tyres are slightly bigger in diameter and wider than the standard 215 17.

 

[RBOOLL99]

Assuming everything was the same, your standard offset would be 68mm. The lowest offset recommendation for a 7.5" wheel is 45mm. Given that your wheels are probably 8" wide that would bring that back to 58, although the official recommendation is 54 given that your tyres are slightly bigger in diameter and wider than the standard 215 17.

So would 55 offset be the ideal offset to run? seeing as I dont want to upset the cars geometry in anyway, I'd like to get it as close as the standard set up is now.

 

[NickD]

So would 55 offset be the ideal offset to run? seeing as I dont want to upset the cars geometry in anyway, I'd like to get it as close as the standard set up is now.

I have seen some extreme variations on standard in my time. I wouldn't classify what you are suggesting as extreme. at 55 offset you will have moved the tyre contact patch 1/2" outboard. You could surmise why Renault when to all the trouble to create rear wings and bumper unique to the RS model then pushed the wheels "so far" into the arches. Maybe it was because they always planned to allow for lower offsets, maybe there was an initial plan for a bonkers mid engine V6, maybe the chassis engineers insisted that they had found the ideal set up or maybe, it was just financially easy given existing parts, time and development cost constraints. Many people on here have fitted wider spacers and different offset wheels.
I don't know where the King Pin inclination relative to the contact patch is on a Clio but assuming you are pushing the contact patch outboard of this intersection then you would perhaps have more torque steer and fidgeting over bumps through the steering which is going to be the most likely thing you would notice and as you will have increased the lever length to the spring and damper then bumps will make the suspension work harder, non of which I expect you would notice in any major way with such a small change. You also might find the rear wants to rotate less, which can be a good thing, or a bad thing depending how you want the car to drive. What I would expect you to notice far more obviously would be any sort of significant change in wheel weight. If you put heavier wheels on you will notice it in the ride and just the way the car responds. As you are already on 18 (I don't know the weight of Renault wheels) if you were to drop to 17" the resultant reduction in weight and taller tyres, everything else being the same, I expect you would particularly notice in and improvement in ride and transmission of high frequency bumps into the car.

 

[peter]

i've got an RB7 with the interlagos wheels (specs : 8X18 ET66) myself. the only aftermarket manufacturer (within my budget) i came across (when looking for some track wheels) to offer the exact same ET spec wheels, was spanish company braid. they can do an 8X18 ET66 wheel (it's called the fullrace A). in the end i settled for the 7X17 ET47 fullrace R (always wanted to go 17" for track wheels).

as stated above, ride comfort has improved (possibly due to the higher sidewall of the 17" tyre, or maybe because the 17" combo weighs 2.5KG less than the 18" combo). the 17" braid wheels stick 6mm further out than the 18" interlagos wheels, but i can't really tell the car behaves differently.

from my little research, i know that the speedline turini 8X18 came closest to the standard spec, with ET60.

evoCorse does an 18" wheel (the sport 18). according to their website, maximum ET is 54. that means the evoCorse wheel will stick out 12mm more than the interlagos. i think that's a reasonable difference, since a lot of clios run OZ ultraleggera and alleggerita 8X17 ET55 wheels without a problem. they extend a further 19mm than the standard 7.5X17 clio wheel. don't know if OZ do an 18" wheel for the clio, but if they, do prepare to pay big money for them.