4000lb with 60/40 F/R weight distribution (wild guess, especially for fully loaded car) gives the front 2400 lb.
One front tire needs to support 1200 lb. Approximation.
5000 total 4 tire capacity = 1250 lb per tire
Now 1250 vs 1200 does not look like much safety buffer.
Krzyś
PS One would need real numbers to come up with needed load index.