How do you hold your lipos down in a 3905 Maxx

They are awesome can hold a wheelie down the street ...alot more torque ...run cool never got over 98 in foot tall grass bogging it down esc was 110...lol....I just got my replacement bellcranks and I will shoot vid and gps it ....highly reccomend it for 99 bucks ...top speed I'd guess 40 give or take few mph ....gps will tell the truth...