winter tires for an x3 2009

Hi I will be changing my 330xi soon for an X3 2009 with the default 17" mags.

The default tire sizes recommended are 235/55/R17.

I have a set of winter tires from my e46 sedan that are 235/45/r17.

Would they fit on the x3? Is it a good idea to reuse them?

If I understand it right the profile of the tires would be lower but they should fit, is that correct?

Are there any disadvantages/dangers to using this tires?

Thanks for the help.

They would fit, and look O.K., except the disadvantages are:

- your X3 would be sitting almost 2" lower (from a quick calculation in my head)

- your speedometer would be reading higher than it aready does (say, 10% high instead of 5%)

- acceleration slightly better, top speed slightly reduced

- not the best mod. for best snow traction (215/60-17 would have been good)

- less protection for your new wheels from potholes, etc.

The danger is that you might get high-centered on a snow drift.

Consider advertising them for sale and look into getting either 235/55's or 215/60's?
Many tire shops give good trade-in deals.

I think the difference between the 45 and 55 series sidewall would be 1 cm, so 2 cm in total height difference which is just under an inch. You probably could get by with those, but as Supercourse said, they aren't the optimum width for snow. The narrower the better for snow. As stated your speedo will be faster than actual. There is a tire calculator for speedometer correction, you just have to search on this forum and find it.

It is a 1.85" overall height difference.

See attached snapshot of a tire calculator:

I stand corrected..

Thanks guys

I guess I have to spend more money on the right tires.

I just hate that I will have to try to sell the old ones and lose money and pay another 1k for a new pair