Large cart pulling - horse or bison

[keoki 29]

Aside from hell horses, would a pair of 5-speed horses or bisons be better to pull a large cart?

I know 4 bison's are the best for a wagon, but what about large carts?

[Cataclysm 6]

Bison are slower than horses...

[lawurm 337]

best stick with 5spd and good gear, also rare cart adds 1km to top speed.