Grow bulldog 500kg plus

Hi please how does the 500kg bulldog bonus for grow work? It doesn’t add anything to me I have it unlocked and no change in tonnage at grow… Martin

Are you at Mass limit?

I have 6999 out of 7000 as before I unlocked it

Then there’s your answer. The perk is fine. You just already have your tonnage maxed to your full mass on on your cab. Take off a movement part and lower its tonnage so that the codrivers tonnage perk will actually do something. Or drop a heavy engine on there.

Mass limit is hard limit - it can only be increased a bit by a motor.
You limit is the smaller of (tonnage OR mass limit). Wheels increase tonnage, motors tonnage/mass limit.