Hi

 

Will I be ok increasing the sidewall size from 50 to 55 on a Karoq? The standard size on my wheels is 225/50/18 and I was thinking of going upto 225/55/18. Has anyone tried this? 
 

Thanks

 

Best say which Karoq you have.

 

Loads of threads with questions about Karoq tyres and info.

http://briskoda.net/forums/topic/498958-tyre-replacement-for-karoq-15tsi-2wd-21550-r18-92w-limited-choices

http://briskoda.net/forums/topic/461043-18"-all-season-tyres

http://briskoda.net/forums/topic/478835-tyre-size-question

http://briskoda.net/forums/topic/454979-wheel-and-tyre-question

Lots more in the Tyre or Wheel sections.

Edited 2 April, 20233 yr by toot

Only problem is the larger diameter which may cause the speedo to under read.  This is illegal.

Speedos can only over read and then by not more than 10%.

 

tom

Never a problem with the sizes people mention here as the speedo over reads as it is on the OE tyres when new, when inflated to ECO pressures even, maybe when Winter Tread tyre of the OE size is fitted,

so the larger diameter / circumference tyres mean the speedo might be accurate, 

& unlikely to under read unless you are going 'Monster truck looks' or some tyre sizes some want on their Yeti. 

2 hours ago, thomas5265 said:

Will I be ok increasing the sidewall size from 50 to 55.

 

The direct answer to that is no.

 

I believe the general rule is that when changing tyres sizes, you should not exceed the original diameter by 1.5%.  If you simply go from 50 to 55 on the same 225 x 18 spec, that'll give you a 3.1% change which takes you well outside the tollerances. In other words, you'd have to recalibrate the speedo if you want to go from 50 to 55 on the same 225 x 18 tyre.

 

My advice would be that whatever you may read on forums, at the end of the day you'll need to inform your insurer if you want to change tyre sizes.  In most cases they may accept or ask an additional premium for modifying from factory specs, but under no circumstances will they cover you if the modifaction makes the car illegal. 

 

 

 

9 hours ago, toot said:

Never a problem with the sizes people mention here as the speedo over reads as it is on the OE tyres when new, when inflated to ECO pressures even, maybe when Winter Tread tyre of the OE size is fitted,

so the larger diameter / circumference tyres mean the speedo might be accurate, 

& unlikely to under read unless you are going 'Monster truck looks' or some tyre sizes some want on their Yeti. 

My 16 “ winter wheels are slightly smaller than the 19” 225/45 standard tyres. Hence at a true 70 the standard tyres read 73 on speedo and winters 75.

easy enough to work out the rolling circumference and compare.

 

If you go here    https://www.wheel-size.com/calc/?wheel1=225-50-18X8ET45&wheel2=225-55-18X8ET45&fcl=50mm&scl=50mm&wcl=30mm&sr=0mm

it will  calculate everything and tell you all you could possibly want to know and more

On 02/04/2023 at 11:21, thomas5265 said:

Will I be ok increasing the sidewall size from 50 to 55 on a Karoq? The standard size on my wheels is 225/50/18 and I was thinking of going up to 225/55/18.

 

225/55R18 is almost the size of a 235/55R18 that the Kodiaq uses.

 

225/55R17 is a Karoq 4x4 tyre size, so 225/55R18 has an outside diameter 1" bigger than this.

 

If you want to go a little bigger, 235/50R18 would give a 1.5% bigger outside diameter.