Hi Everyone,

I have a 2019 Škoda Karoq 1.6 TDI Style DSG that has crossed 85.000 km and I am looking to upgrade tires. I currently have 215 50 R18's, however would really like to upgrade to 215 55 R18's as there are many more options to choose from for less money and more importantly would provide for a more comfortable ride. I do not believe clearance would be an issue as it seems like there is plenty of room for the extra 5% of sidewall however I see the recommendations of going with a 55 sidewall are with a 205 55 R17. Does anyone have experience in going with this size tire and if so what are the pros and cons? Would you recommend it? (I do not want to purchase 17 inch wheels). Thanks in advance.

I put the two dimensions in a tyre size calculator, and the increase in diameter comes out at 22mm, an increase of 3.27%. This is above the recommended maximum increase of 2%

 

 

I have the same car, with the same size of standard tyres. I'm running 235/50x18 on it on different wheels, they are 1/2 inch wider than the standard wheels. The ride is much better on the current wheels. There is no problems with clearances.

It's quite common for car owners to keep the rims that they have and either go up in width by one size (ie. 10mm) or in aspect ratio by one size (ie. 5%).

 

Going up one size

215/50R18 standard size

225/50R18 one size up in width

215/55R18 one size up in aspect ratio

 

The Karoq's 18" rim specification is 7Jx18 ET45 5/112 57.1

 

As you can see in the chart below, 225/50R18 has a 1.5% bigger outside diameter compared to 215/50R18 and 215/55R18 has a 3.2% bigger outside diameter compared to 215/50R18.

 

Outside diameter of tyres

215/50R18 672.2mm

225/50R18 682.2mm (1.5% bigger outside diameter compared to 215/50R18)

215/55R18 693.7mm (3.2% bigger outside diameter compared to 215/50R18)

 

As you can see in the chart below all three of these tyre sizes fit the Karoq's 7J rim width. The reason the 7.0 is highlighted is because a 7" rim width is standard for all three of these tyre sizes.

 

ETRTO approved rim widths for passenger car tyres

215/50R18 6.0-7.0-7.5
215/55R18 6.0-7.0-7.5
225/50R18 6.0-7.0-8.0

 

Example of 215/55R18 tyre size...

 

Continental AllSeasonContact 2 215/55R18 95T (Euro label B B 70dB) (3PMSF symbol, ie. winter rated) (all season tyre)

https://www.camskill.co.uk/m141b0s11740p220584/Continental_Tyres_All_Season_Car_Continental_Conti_All_Season_Contact_2_215_55_R18_95T_TL_Fuel_Eff_%3A_B_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_70dB

 

According to wikipedia, the Karoq 1.6TDI (manual and automatic gearbox) has a top speed of 188km/h (117mph), so T speed rated tyres are sufficient because these are rated up to 190km/h (118mph).

 

Edited 22 June, 20241 yr by Carlston