Joy of joys, I've got myself back into a vRS after selling my MkII six and a half years ago. Loving it, but at present it has four odd (but tread-rich, at least) tyres that I'll want to swap at some point. Including one budget one, FFS. 

 

My question is whether anyone still on here (it's a lot quieter than it used to be) has any experience of swapping the standard 225/40 tyres for 235/40s, purely for a bit of extra rim protection. Is it worth the extra cost? Does it actually protect the rim or not? Pic shows the 225.

Can’t comment on the 235s however I’ve just replaced a worn pair of 225/40 Michelin PS5s with Goodyear Eagle F1 Asym 6s (currently £35 off for 2 and £70 for 4 at ATS) and both have a thicker section of rubber that runs around the circumference of the alloy to give some extra protection. I think most premium brands do.
 

Never had any issues running the standard tyre size with the 18” Gemini alloy other than when the wife took the car out for the first time and properly had a go at curbing it! I don’t think any amount of protection would have helped in that scenario.

Wives, eh? Thanks for the response, I'll maybe risk the standard size in that case. Halfords have a very tempting deal on Premium Contact 7s (just over £100 a corner), or otherwise something on an ATS deal.

1 hour ago, CookieMonster87 said:

other than when the wife took the car out for the first time and properly had a go at curbing it!

 

Definitely related to Mrs Gaz 🙄

205/50R17 fitted to 6J rims would offer a lot of rim protection because the sidewalls bulge out by about 15.8mm each side. However, on the VRS these are really meant as a winter tyre size. The Scout's 225/50R17 tyre size offers a similar 15.6mm of sidewall bulge each side on its 7J rim width.

 

What is happening, is that once you get up to a 50 or higher aspect ratio tyre (ie. 50, 55, 60, 65, etc.) the sidewalls tend to bulge out from the rim a lot more than the 45 or lower aspect ratio tyres (45, 40, 35, etc.).

 

Bear in mind in the chart below that according to ETRTO 235/40R18 and 235/35R19 need at least an 8J rim width, ie. 7.5J is undersize for these tyre sizes. 

 

Amount sidewalls bulge out each side of rim (the bigger the number, the more rim protection from kerbing damage)

205/50R17 fitted to 6J rim 15.8mm

225/50R17 fitted to 7J rim 15.6mm (Scout tyre size)

205/50R17 fitted to 6.5J rim 12.45mm

225/45R17 fitted to 7J rim 8.6mm

235/40R18 fitted to 7.5J rim 7.25mm (non-standard tyre size) (undersize rim width, ie. not ETRTO approved)

235/35R19 fitted to 7.5J rim 7.25mm (non=standard tyre size) (undersize rim width, ie. not ETRTO approved)

225/45R17 fitted to 7.5J rim 5.25mm

225/40R18 fitted to 7.5J rim 4.75mm

225/35R19 fitted to 7.5J rim 4.75mm

 

6Jx17 ET48 5/112 57.1 alloy rim CRYSTAL (from Octavia MK3)

https://eshop.skoda-auto.cz/cs_CZ/alu-kola/c/alloyWheels?sort=priceAsc&q=%3AscoreDesc%3AcarType%3AOctavia%2BIII%2B%282017%2B%29%3ArimDiameter%3A17%22#

 

Edited 7 October, 20241 yr by Carlston

Struggling to understand the relevance of most of that to the OP question 🤔 

10 hours ago, SC03OTT said:

Struggling to understand the relevance of most of that to the OP question

 

Quote from OP...

 

"My question is whether anyone has any experience of swapping the standard 225/40 tyres for 235/40s, purely for a bit of extra rim protection. Does it actually protect the rim or not?"

 

In summary, the answer is yes but not by much.

 

To put the numbers into context, at least 15mm of tyre sidewall bulge will give good rim protection and at least 18mm of tyre sidewall bulge will give excellent rim protection.

 

For example a 215/60R16 fitted to a 6.5J rim (eg. Superb MK3) gives good rim protection because it has over 15mm of tyre sidewall bulge and a 215/60R16 fitted to a 6J rim (eg. Karoq front wheel drive) gives excellent rim protection because it has over 18mm of tyre sidewall bulge.

 

Here's another couple of interesting examples where there may be only a 1" difference in the diameter of the wheels, but when it comes to rim protection the difference couldn't be more stark.

 

Amount of tyre sidewall bulge on Karoq 4x4 (18" and 19" wheels)

225/50R18 fitted to 7J rim (over 15mm, so good rim protection from kerbing damage)

225/45R19 fitted to 8J rim (less than 3mm, so almost zero rim protection from kerbing damage)

 

Amount of tyre sidewall bulge on Kodiaq MK1 (19" and 20" wheels)

235/50R19 fitted to 7J rim (over 18mm, so excellent rim protection from kerbing damage)

235/45R20 fitted to 8J rim (less than 6mm, so almost zero rim protection from kerbing damage)

 

Edited 8 October, 20241 yr by Carlston

On 07/10/2024 at 20:04, CookieMonster87 said:

Can’t comment on the 235s however I’ve just replaced a worn pair of 225/40 Michelin PS5s with Goodyear Eagle F1 Asym 6s (currently £35 off for 2 and £70 for 4 at ATS) and both have a thicker section of rubber that runs around the circumference of the alloy to give some extra protection. I think most premium brands do.
 

Never had any issues running the standard tyre size with the 18” Gemini alloy other than when the wife took the car out for the first time and properly had a go at curbing it! I don’t think any amount of protection would have helped in that scenario.

 

My Assy 6s did an excellent job of protecting my wheels from an errant kerb yesterday. Was expecting the worst but there's just a black rubber mark on the rim.

+protection -looks

I'm running Goodyear Eagle F1 Asymmetric 6s on the front of mine. They have much better rim protection than the Yokohamas that are on the rear (and were on the car when I got it). When ATS have an offer on I've found their prices very competitive - I think I paid about £170 for the pair of Goodyears fitted.

 

There wouldn't be a huge amount extra sidewall by switching to 235/40s. I haven't looked at the price difference. I'm intending to stick with 225/40s all round on mine.

Edited 26 October, 20241 yr by petrolbloke