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Michelin's 225 - 40 - 18 considerably cheaper than the 205mm wide version but struggling to decide on which - the car was allegedly designed and engineered to run on 205's so wary of upsetting the 'balance' of the car. The wider tyre provides a bigger contact patch so more grip in the dry but presumably more chance of aqua planning in the wet plus with the deeper aspect ratio will provide more protection against potholes but the extra grip in the dry may increase the torque steer plus although very marginal, increase the unsprung weight at each corner.

Probably over thinking but any help will be much appreciated.
 

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Your widening the cars track by 40mm 20mm each side so it will follow the camber in the road more potentially making it harder to drive.

Also your putting 225 tyres on rims designed for 205 tyres which could cause the wider tyres to flex again upsetting the handling.

I'm guessing you bought the car because you like the way it handles and does the money saved on the tyres matter more than the handling of the car.
 

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According to this table I've found for ideal tyre widths 205s are the minimum you should fit on 7.5 width rims.
215 or 225s are ideal. Plenty seem to be fitting 225s at the minute rightly or wrongly.

Rim width Minimum tyre width Ideal tyre width Maximum tyre width

5,0 Inches 155 mm 165 or 175 mm 185 mm

5,5 Inches 165 mm 175 or 185 mm 195 mm

6,0 Inches 175 mm 185 or 195 mm 205 mm

6,5 Inches 185 mm 195 or 205 mm 215 mm

7,0 Inches 195 mm 205 or 215 mm 225 mm

7,5 Inches 205 mm 215 or 225 mm 235 mm

8,0 Inches 215 mm 225 or 235 mm 245 mm

https://www.tyres-pneus-online.co.uk/tyre-equivalence-advice.html

Also, aren't you widening the track by 10mm a side, 10mm wider inside the tyre and 10mm on the the outer from the centre line of the tyre?
 

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Just for kicks,
205/40-18 225/40-18 Difference

Diameter inches (mm) 24.46 (621.2) 25.09 (637.2) 0.63 (16) 2.6%
Width inches (mm) 8.07 (205) 8.86 (225) 0.79 (20) 9.8%
Circum. inches (mm) 76.83 (1951.56) 78.81 (2001.82) 1.98 (50.27) 2.6%
Sidewall Height inches (mm) 3.23 (82) 3.54 (90) 0.31 (8) 9.8%
Revolutions per mile (km) 824.65 (512.41) 803.94 (499.54) -20.71 (-12.87) -2.5%
 

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I'm guessing you've done thousands of miles with them then just to give a realistic opinion then?

Just because something fits doesn't make it the best option if your doing real mileage in a car.
I said I put them on earlier in the week.....but alrighty then.

I didn't say it was the best option, I stated I put 225s on my car and I have no issues with them, other than the speedo is actually accurate now.

My first post on here btw, just trying to be helpful.....
 

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Your widening the cars track by 40mm 20mm each side so it will follow the camber in the road more potentially making it harder to drive.

Also your putting 225 tyres on rims designed for 205 tyres which could cause the wider tyres to flex again upsetting the handling.

I'm guessing you bought the car because you like the way it handles and does the money saved on the tyres matter more than the handling of the car.
No, you're widening it by 20mm overall as the 20mm per tyre is across the entire tyre, so 10mm each side per tyre.

Also, wider tyres will not not tramline as much as skinnier tyres.
 

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Just to add my 2 pence worth, I've recently fitted new wheels and tyre to my mk6. There a 7j wheel and replaced a 7j wheel, I opted to fit 195's this time instead of the 205's that were fitted to my car on the previous set of wheels. After a fair few miles of driving in mixed weather conditions I can't believe the change in reduced grip. I knew the tyres would fit, I knew they were on the smaller side of tyre for the wheel.

im guessing what I'm trying to get at is they have a recommended tyre size for a particular size wheel for a reason, will I be sticking to it once I get through the current set that I have fitted now? Definitely.
 

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I said I put them on earlier in the week.....but alrighty then.

I didn't say it was the best option, I stated I put 225s on my car and I have no issues with them, other than the speedo is actually accurate now.

My first post on here btw, just trying to be helpful.....
Will be interested in your views over the next few weeks you run them against the 205s Vintage. Cheers
 

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Will be interested in your views over the next few weeks you run them against the 205s Vintage. Cheers
Sure, but I only got the car two weeks ago and it had the 17" wheels with 205s that needed replacing. I used the chance to buy the perf 18" wheels. The link earlier was what I looked at in relation to wheel widths. 205 is the min for 7.5j. Recommended is 215 or 225, so the 225 made sense to me. The car really struggled with the cold damp roads here for first two weeks and new tyres have cured that, but no idea how new 205s would have done. They also look better imo.
 
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