Changing from 235 40 18 to 215 45 18 pros and cons

Changing from 235 40 18 to 215 45 18 pros and cons

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Heaveho

Original Poster:

5,899 posts

186 months

Friday 20th December 2024
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Is there any disadvantage to downsizing tyres as above? The rims are 8J, 215 is the minimum that is meant to be used on this rim width. The sidewall heights are less than 3mm different between the 2 widths, so I'm guessing the aesthetics will be negligible. The decision therefore is purely on cost and ride comfort. It's not a performance vehicle, this is a combination of anthracite Focus ST line alloys onto my black 2018 Ford Connect. The tyre of choice for me would be Goodyear, and the addition of the alloys is purely to improve the appearance of a nice looking van.

I intend to see how it drives on the 235s the alloys came on, but they need replacing. I don't want to make a potentially expensive mistake, and can't see the point of running a 235 unless there's a good reason to do so.


GreenV8S

30,703 posts

296 months

Friday 20th December 2024
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It will alter the handling characteristics slightly, resulting in slightly more steering feedback, a slightly more progress break-away near the limit of grip and slightly lower peak grip in cornering. A narrower tyre on a wider rim is typically a better combination than the other way round - as the tyre deflects sideways under cornering loads the tread will tend to left the outside edge, which compensates for the body roll induced camber changes.

You'll need to ensure the tyre does actually fit the rim OK without stretching, although you seem to have covered that. You'll need to check the rolling diameter hasn't changed too much, although you seem to have covered that too. Also be aware that the rim will be slightly more vulnerable to kern strikes - no idea how much of a concern that is for this vehicle.

E-bmw

10,651 posts

164 months

Friday 20th December 2024
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Heaveho said:
The tyre of choice for me would be Goodyear,
Try being a bit more specific.

Goodyear make some excellent tyres & probably also make some cr@p ones.

MustangGT

12,808 posts

292 months

Friday 20th December 2024
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Another point to consider is whether it was offered as an option on that vehicle in the first place. Insurance companies often insist on OEM tyre sizes, you can usually swap between different OEM offerings but not non-standard options without a premium hike, if they cover it at all.

Heaveho

Original Poster:

5,899 posts

186 months

Friday 20th December 2024
quotequote all
E-bmw said:
Try being a bit more specific.

Goodyear make some excellent tyres & probably also make some cr@p ones.
Asymmetrics of whatever persuasion the numbers are up to now. 6 I think.

Heaveho

Original Poster:

5,899 posts

186 months

Friday 20th December 2024
quotequote all
GreenV8S said:
It will alter the handling characteristics slightly, resulting in slightly more steering feedback, a slightly more progress break-away near the limit of grip and slightly lower peak grip in cornering. A narrower tyre on a wider rim is typically a better combination than the other way round - as the tyre deflects sideways under cornering loads the tread will tend to left the outside edge, which compensates for the body roll induced camber changes.

You'll need to ensure the tyre does actually fit the rim OK without stretching, although you seem to have covered that. You'll need to check the rolling diameter hasn't changed too much, although you seem to have covered that too. Also be aware that the rim will be slightly more vulnerable to kern strikes - no idea how much of a concern that is for this vehicle.
Thanks for the input, that's all useful. The speedo reading will alter by 0.8%, so negligible in terms of rolling radius change. One of the reasons I like Goodyear is the rim protector, but I just generally like the feel of Eagle F1s on anything and use them on 3 of my other vehicles. It sounds like there are more pros than cons to the smaller tyre.