tyres mk1

[speedmachine]

hi anybody know whats the widest tyre size i can use on mk1 2000 185 ?? 13

[johnnydog]

It really depends if you want to keep the same rolling circumference as the original tyre size of 175 13, which is now labelled as 175 80 13. Keeping this the same means theoretically the speedo accuracy won't be be affected.
The 80 figure means that the height of the side wall is 80% of the width of the tyre.
A 70 profile (70% of the tyres width) means you can go wider, whilst maintaining the same tyre wall height, therefore maintaining the same rolling circumference. Equally with a 65 of 60 profile, but the wider you go, the more likely you are to get the inside tyre wall fouling on the suspension components when operating towards full lock.
In a 70 profile, the correct tyre size to maintain the exact rolling circumference of a 175 80 13 tyre is 200, but unfortunately tyres are only commonly produced in 195 or 205 widths.
In a 65 profile, a 215 width tyre gives virtually the same rolling circumference as the original tyres size, but obviously is a much wider tyre, which may cause the issues mentioned above.
There is a website on which you can play around with tyre sizes to get the correct or your preferred rolling circumference to match the original, and it gives percentage inaccuracy and speedo error at 70mph -
https://www.tyremen.co.uk/tyre-size-calculator
Hope this makes some sense and is of some help.

[Charles H]

The other thing you need to consider is the wheels. Mk1 wheels are only 4.5J, 4 1/2 inches wide. Wider tyres then have more of a tendency to 'roll' off the rim. Mk2 steel wheels are 5J and the later 'S' alloys 5.5J. Even using the Mk2 steel rims makes a huge difference.