Newbie Kart

It depends on the person, but I like Toad's kart (which you won't unlock until later in the game). I usually take bowser Jr. And the red koopa in a team and take the koopa kart with 4 acceleration and 2 speed (if I remeber correctly). Once I got the Toad kart, then I started using that one.

At the beginning of the game I used the Koopa Kart for small racers, and someitmes the Waluigi one if I decided to use mediums for a change. I never used large karts.

After that, I just used the Toad Kart once I unlocked it. I found it to be the most useful.

NEVER USE MEDIUM KARTS!!!THEY R TOO UNRELIABLE, only use heavy for like 50cc, and anything else light karts, I would suggest this:
Heavy:bowser and baby mario in bowser kart
Light:(note, this is for when you just start)baby bowser and baby luigi in the little mario buggy(u can exchange baby bowser with baby mario)

Toad and Baby Mario in Toad Cart it is relly easy to handle and it is very vast with a high excelleration speed

Some cars that are fast-light cars are toad's,koopa tropas,and bowser junior's. Fast-medium carts are waluigi's,mario's,and birdo's.fast-heavy carts usually depend on your people. EX:Bowser and toad,toadette,baby mario,or baby luigi on bowsers kart.donkey kong could be with them too.same as pirahna pipes and boo pipes and warios. Best for turning are light:diddy kong's.Medium:yoshi's. Heavy:Bowser's.Hope this helps.