bike rack fuel economy

[joker]

Hi

I have a 1990 318is and am driving to France (700 miles) on holiday in early June.

I desperately want to take a couple of bikes but am worried about the effect on fuel economy and performance, particularly as fuel is so expensive now and I want to maintain a good 85 or 90 on the French autoroutes.

Any help would be appreciated.

Cheers

[Bob_S]

it will effect it slightly 3-4mpg max