Let us brake down the facts. The classic ini.
The current speed for the APC is 35.
Bikes have even 40.
The NOD buggy and Humm-vee have only 30.
I find this weird, most of the lighter vehicles have lower speed and are wheeled.
A tracked vehicle should be the slower one, or make up with a higher cost.
Most tracked vehicles have 18 or 12. With the exception of the Stealth tank, which is 30.
Infantry range from 6 to 10 with their speeds. They need micro to dodge the speed of 18. Any higher speeds require a lot of anticipation.
And groups of tanks already have no problem crushing infantry.
We all know that roads have a positive effect on vehicle speeds. The wheeled gain more than the tracked.
They will be on par, on roads.
There for, I suggest to have the APC a movement speed of 24/25. Making it faster than any other tracked vehicle. With the exception of a Stealth Tank.
If it proves to be to slow against certain defences. Slowly add speed until it reaches 30.
If you made other changes on speeds in the community balance, by logic, the speed for the APC could be different too.