[Mac147]

Hi guys, I've been trying to install a roof rack on my 520D F10.

I bought the roof rack which can be fixed directly on the four existing female threads on top of the car. But the screw size seems to be wrong.

I've tried M6 which is slightly small, M7 to be too big. Then I tried 1/4 UNC which seems to be the right size but I can only get it in a little bit.
Next, I tried 1/4 UNF, this one worked better, but it still couldn't reach the bottom.

Does anyone know the exact size of the threads? Or does anyone know how can I find out?

[ezaircon4jc]

Originally Posted by Mac147

Hi guys, I've been trying to install a roof rack on my 520D F10.

I bought the roof rack which can be fixed directly on the four existing female threads on top of the car. But the screw size seems to be wrong.

I've tried M6 which is slightly small, M7 to be too big. Then I tried 1/4 UNC which seems to be the right size but I can only get it in a little bit.
Next, I tried 1/4 UNF, this one worked better, but it still couldn't reach the bottom.

Does anyone know the exact size of the threads? Or does anyone know how can I find out?

Did you buy the BMW rack? It should have come with a bolt to chase the threads to remove any residual paint.

[OrcaPod]

I had to look for a new bolt for OEM bmw roof rack on my 2011 528i.
the bolt with the follows specs worked:
M7 with 1.00mm step (make sure that its 1.00 mm step and not 1.25)
These are not standard bolts in North America so it was hard to find one here in Canada with proper length.

Also I almost damaged the female threads on the roof when I was trying to force the original bolt ( i didn't see that thread on original bolt was damaged a bit).
Make sure to inspect bolt's thread and try not force the bolt too hard.

[Mac147]

hi ezaircon4jc, I didn't buy a BMW rack, it's ridiculously expensive.
Bought mine from China, it worked on my friend's BMW 5 series so I sort it should be fine. I guess the BMW cars sold in China and Australia are different.

hi OrcaPod, thanks for your help. I don't think M7 works on my car, I tried them and they are obviously too large for the female threads.

I'm gonna go to a bolts store and try to get some professional advice next.

[ezaircon4jc]

Originally Posted by Mac147

hi ezaircon4jc, I didn't buy a BMW rack, it's ridiculously expensive.....

I don't know how much you paid or what you think is ridiculously expensive, but I paid $211 for my BMW base system.