9 replies to this topic

[Colakurt]

I would like to fit some 13" wheels to my MPI mini from 96. But I just can't figure out what the ET Offset should be, in order to make the wheels fit my mini.

The wheels I would like to fit, is a set of 13" rims that is 6" wide and with 175/50-13 tires. The ones i got on now is a set of 12" rims that is 4.5" wide with 145/70-12 tires with an offset at +35.

I got the standard non-sportspack plastic wheel arches on now, but I'm planing on fitting a set of Wood & Pickett fiberglass arches instead.

So how do I figure out how small a ET my wheels can have, before the tires begins to scrape against the wheel arches and fenders?

Would a set of 6X13 Ultralite wheels with an offset at +10 fit my car with the new WP arches?

[Jakeclubby]

i think they should be fine but get a second opinion....

[Dan]

You won't be able to use Wood and Picketts without a lot of work. Wood and Pickett arches are mounted to the wheel arch lip, you will have to cut that away and reshape it to allow 13" rims to fit. You would have to fill the inside of the W&P with something to allow you to bond mounting points into it to fit through the wing, unless there is a W&P copy out there that mount differently. There is no way to be able to fit 13" rims of any size or offset to a disc braked car without trimming the body AFAIK.

[Colakurt]

What about some 12"?
I can see that a lot of people use them with the Wood and Pickett arches. Does anyone know the offset of the Wood and Pickets own 5" rims? cause then i should be able to calculate, which wheel sizes that would fit?

[Dan]

Yes 12" rims fit with W&P arches.

[freshairmini]

you could use fibreglass to modify the W&P arches to mount differently. Not sure how easy it would be tho.

[Colakurt]

Would I need some steering rack limiters when i fit the superlight 6X12 rims with A539 tyres? or am i going to be ok without them?

[ado15]

The clearance issue is actually to do with the offset, or rather the position of the outside edge of the tyre. There is no radial size difference between 12" and 13" tyres used on a Mini. i.e. the 175/50x13, 165/60x12 and 145/70x12 are all basically the same rolling diameter. Even the 10" tyres are only about 10mm smaller diameter.

The issue occurs when the steering is turned. The wheels move in an arc and, hence, forwards or backwards in the arch. The outside edge of the tyre gets close to the arch as it moves forward in the arch (RHS moves forward as you steer left & visa versa).

The same problem would happen if you fit whopping spacers behind your standard wheels. Basically, the further out the outside edge of the wheel is, the greater the problem.

The lock stops on the SportsPack are needed because the factory wheels are rather 'inset' and touch the inner arch at full lock with a standard rack. Most aftermarket wheels are more 'offset', so don't run into this issue. Instead it's the problem outlined above.

[Dan]

There is a diametric difference, but mainly due to the construction of the tyre. The lower the profile of a tyre, the squarer the shoulder profile is. This is why some tyres will rub and others don't, and it can't just be defined by tyre size because different manufacturers build them differently. A squarer tyre will have a larger diameter closer to the outside edge. To sort out the tyre clearance, you just have to fit the ones you want and see if they clear.

You shouldn't need rack limiters with any 12" rims.

[dave1293gt]

Dan is quite correct. I had 175/50/13 bf goodrich on my old mk2 fiesta.
When i needed new ones i upped size to 195/45/13 conti's and gained clearence. These were on 7x13 rims