Debating on 18" vs 17" & Sport Select

[monkeyhanger]

Is there a photo of one with 18s to compare?
The arches still look a bit empty with the 17s.

Pictures of Monkeyhanger’s red GTI+ on 18” Brescia’s at the link below (5th post down on page 7). This is before he got new tyres fitted, so it’s on the factory fitted Bridgestone tyres;

viewtopic.php?f=71&t=70453&start=90

Whether the GTI has 17” or 18” wheels, with the factory fitted tyres (Bridgestone Turanza on 18” wheels or Michelin Primacy on 17” wheels), the arch gap will essentially be virtually the same because the overall diameter and circumference of the wheel+tyre changes very little, which means the ride height also changes very little;

18” Factory fit Brescia alloys (7.5Jx18” ET51) and 215/40 R18 tyres - diameter; 629.2mm, circumference; 1,976.7mm

17 Factory fit Parker alloys (7.5Jx17” ET51) and 215/45 R17 tyres - diameter; 625.3mm, circumference; 1,964.4mm

Difference in ride height between the two; 1.95mm.

You’d need to lower the car if you wanted a reduced arch gap.

Now I have my Michelins on(225/40 R18), the diameter has increased by 8mm, effectively filling the arches further than standard 18" Brescias on 215/50 R18 tyres by 4mm. My Polo GTI+ sits very high on its springs when compared to my Golf R.

[monkeyhanger]

Oooh, the 18s do look nice....

Shhhss now Yes they look the part! I also like to believe that VW engineers designed and tuned the suspension with the 17" alloys, why else would they be the standard fit? Im probably singing for the choir here

Not sure they'd design the suspension specifically for the 17" wheels - I wonder what the unsprung weight differences are between the 2 wheels with their respective tyres? The extra rubber on a 215/45 R17 tyre may be approximately the same weight as the extra alloy in the 18" wheel. The differences are likely to be marginal - still plenty of sidewall in both tyres - not as if it's some super slim tyred 20" wheel where the tyre looks like it is painted on.

[phillos]

Oooh, the 18s do look nice....

Shhhss now Yes they look the part! I also like to believe that VW engineers designed and tuned the suspension with the 17" alloys, why else would they be the standard fit? Im probably singing for the choir here

Not sure they'd design the suspension specifically for the 17" wheels - I wonder what the unsprung weight differences are between the 2 wheels with their respective tyres? The extra rubber on a 215/45 R17 tyre may be approximately the same weight as the extra alloy in the 18" wheel. The differences are likely to be marginal - still plenty of sidewall in both tyres - not as if it's some super slim tyred 20" wheel where the tyre looks like it is painted on.

I know it has a negative impact on the WLTP rating opting for the 18s. Largest I've had on cars is 17", and with 215/45s im still a little scared accidentally hitting potholes. 18s would scare me even more.

[Andy Beats]

It's not so much the wheel size that increases pothole risk, it's the profile of the tyre.
They're the 'barrier' between road and wheel.
My Alpina BMW had 19s with 30 profile tyres, they got damaged far too many times for my liking - I had at least 4 repairs to the wheels.
But my wife's Sportage has 19s with much higher profiles and I don't maniacally avoid potholes in it like I did the BMW.