March 10 through March 27, 2020: Finalizing Front Up-TravelWhen I fit 40s the first time I was mainly concerned with turning clearance, so I only trimmed fore and aft both tires. Now that I'm finally at the point where I'd like to start tuning the suspension, the first step is to set the up-travel
When I built my 1981 Hilux, I ran 14" shocks up front (leaf sprung). The typical design on these trucks is to only run 12s, but being in my early 20s I wanted that "mad flex, yo". It ended up being a bad decision because the up-travel was greatly limited and I discovered that when a truck is heavily loaded, up-travel is more advantageous as you can maintain a level body when it's needed the most. Having a ton of downtravel isn't always useful anyhow: Just because a tire can drop doesn't always mean it'll have weight acting on it to convert into sufficient tractive force. In contrast, the tire which is stuffed the most by definition has the highest force acting on it which is precisely when you want the suspension to work to maximize a tire's ability to use traction
Here is an old pic of my Hilux with 14s in the front. As you can see the driver front shock is nearly at it's bumpstop yet there is a large amount of clearance over the tire
Limited front up-travel will result in things like this. If there was more up-travel on that driver front tire then the body would be more level and we'd have less of a load on the passenger rear tire
There is no reason to be this sideways, or for the poor rear to be maxed out, or for this to look so difficult
Finally, perhaps not the best pic, but this is many years later where I've switched to 12" front shocks providing something like 4 or 5-inches of more up-travel at the tire when articulated. Note how level the body is despite being crossed-up. This wouldn't be possible if that driver front didn't have sufficient up-travel
