Marks on roof

[griebel]

I have some weird marks on my roof. They are shiny and I tried cleaning them and it makes no difference. Any ideas on where they came from and if I can get rid of them?

[garz747]

Hard to tell but looks like wear points from folding have caused the top material to glaze. There are some color dies/resto products that may be used.... Mines a coupe. Clean car BTW!

[racerbruce]

I agree with garz747,
I have similar marks on my convertible top; it appears to be related to folding when the top is down (stored); I have a few "shiny" marks that are linear in shape and it is due to where the top just barely touches the small black plastic trim piece that circles the opening just above the trunk lid; while my factory warranty was still in effect, I had these wear marks reviewed and BMW refused to adjust the top to prevent this minor wear area free from touching the referenced trim piece.

[griebel]

Ok thanks

[fiberguy]

Warning – science ahead from a retired textile guy!

If you look at top’s fabric with a strong magnifying glass, you will see many small fibers protruding from the surface of the yarns that make up the fabric. (BMW’s are normally Haartz Twillfast acrylic fabric.) In the lighter looking areas, these fibers have been worn away or packed down. This changes the specular reflectance (see Wikipedia) of those areas, just like running your finger through velvet changes its appearance. The underlying color has not changed, but the reflected light and thereby our perception of the color has.

Some fabrics, like suede, are actually run through a sanding process which changes the surface and gives them their unique appearance.

I know that this sounds crazy, but I VERY LIGHTLY use a 3000 (Yes, 3000) grit foam sanding pad occasionally on shiny spots. The result is not perfect and there are some very shiny areas that I can’t improve, but it does help the appearance for me. Getting some abraded, shiny areas is inevitable – it’s the price of enjoying the wind in your hair.

Obviously, try this on a small area in the least conspicuous place possible, since we know that replacement tops are absurdly expensive!

Oh – and never, ever leave the top down when the car is parked.

[griebel]

Thanks for the info. The only time I put the top up in for storage in winter, and to wash the car, otherwise it sits in a garage. My thought was to use the motor as little as practical. Maybe that's not the best.

[griebel]

thanks

[fiberguy]

Shiny spots in top vs. roof motor --- life's a compromise!

My philosophy on this is, since I keep the car in a garage and check/clean the drains every six months, I'll gamble on the motor holding up. It seems that water damage is the preponderant motor killer.

Now, if you want real fun - my wife's 10 year old 328i with the origami convertible top makes the ZM top look like child's play. Minor leaks go straight to the trunk and into the radio power amp causing howls and static that you can't turn off. Since her new X3 bumped the 328 from the garage, a car cover is mandatory.