Replica Alloy Wheels

[golfhappy]

Does any body know why the cars wheel arch gap looks bigger with the 18" wheels on? surly I would of thought it would be the opposite and the wheels would fill the arches

Going from 16's to 18's it's not surprising. You've raised the car by 2 inches. Will defo need lowering for wheels to fit the arches better. This will help improve the handling too. Getting some decent tyres will make a big difference (Goodyear eagle f1's for example). Personally I'm sure it's worth the risk putting them on the reps tho. I'd just sell the reps and get some decent genuine wheels instead. Oh and put some good tyres on!

Surely if the car was to rise the it would only be by 1 inch as from the centre of the wheel there would be an inch all the way around to give a total of 2 inches in total?

Also surely you would have lower profile tyres on the bigger rims to keep the total circumference of the wheel would be the same otherwise the speedo would be reading incorrectly? If this it true then the even tho the rim is bigger the overall size is the same so the arch gap would be the same??

Usually if you were going for smaller/larger rims you would work out that rolling radius done with the aspect ratio of the tyres...which is the width 215 and say 45 which would give an tyre would make the tyre wall height of 96mm. so from dead centre of the wheel 9" x25mm =225mm +96mm =321mm so 321 is the radius then pi r2 will give the circumference. Your right that working out this will keep the speedo accurate. Or is it pi d ? 

[dubber36]

Does any body know why the cars wheel arch gap looks bigger with the 18" wheels on? surly I would of thought it would be the opposite and the wheels would fill the arches

Going from 16's to 18's it's not surprising. You've raised the car by 2 inches.

This is not the case. With the correct size tyres, i.e. going from 205-55-16, to 225-40-18, the overall diameter of the tyre will remain the same as before. The centre of the hub will stay in the same position in relation to the ground, therefore so will the distance between the top of the tyre and the wheel arch.

What is happening is an optical illusion. Similar to putting equal portions of food on different sized plates. A pile of spag bol on a large plate will not look as much as the same amount piled up on a small plate.