Suspension question

[hayden55]

Lowering a vehicle you plan to tow with is a bad idea. Aren't you going to be squatting anyways since you're towing a huge camper?
Although I agree with the body roll. They are awful. Maybe you can call eibach and ask if a tundra front sway bar will fit.

[Taylor95]

Originally Posted by hayden55

Lowering a vehicle you plan to tow with is a bad idea. Aren't you going to be squatting anyways since you're towing a huge camper?
Although I agree with the body roll. They are awful. Maybe you can call eibach and ask if a tundra front sway bar will fit.

I don't think it will be too bad. I only want to lower it 1-2 inches... and I will be getting a few things to help me tow like air bags and a weight distribution hitch.

[Ecky]

Maybe you already know all of this, but here's my understanding and experience:

Cutting the stock springs is an option, but I wouldn't go a full 2 inches. As the springs get shorter, the spring rate goes up, which somewhat helps offset the reduced travel, and it can be a reasonable option if you're not removing much, especially on vehicles with a lot of travel to begin with.

Swapping in a lowering spring is typically a better option because they're usually a lot stiffer, and that prevents slamming the bump stops, which is a LOT harsher than upping the spring rate. The Insight is notorious for slamming the stops in the rear, and putting in stiffer springs really improves the ride harshness. You do, however, have to live with a stiffer ride on a day to day basis.

Changing the spring rate throws off the damper tuning. Depending on how much stiffer the springs get, you may find you start to have oscillations or bouncing in the rear if you don't change the damping as well.

Coilovers are the best of both worlds because (depending on the design) you can keep the full suspension travel while also dropping the ride height, by raising or lowering the lower fork, rather than cutting travel and increasing the spring rate. Most also have adjustable damping rates so you can tune it for the springs. If you want a stiffer spring on a coilover, you can even keep the full travel by adding a helper spring that fills the gap when the vehicle is off the ground.

My experience is that, leaving the rear of the vehicle high often hurts fuel economy the most. Just as an example, the front of my car was a full inch and a third lower than the rear for a little while, and when I finally got around to reducing that to ~3/4" difference (I too keep the rear high for towing), there was a noticeable improvement in both handling and fuel economy.

[M_a_t_t]

You could just wait til you have the camper (didn't see it in this thread so I don't know the details), then put a thin board loosely attached to the bottom (using something like an F-clamp) that would represent the lowered body. Then pull the camper around hitting some bumps. If you "bottom out" the axle then the board will move. This way you can test how using a similar spring rate while only lowering it would affect it.

I've got my van lowered 2" and I tow a car trailer every once in awhile (up to 4200 lbs). The van is only rated for 5500 lbs so I'm close to the limit. Unless you are maxing your tongue weight capacity out then I think you will be fine.

[Drifter]

Originally Posted by freebeard

Is there a red or blue air bag inside the coil spring? What's #18?

It is a bump stop ("rear spring bumper" in Totota speak). I still can't post links, but...

parts (dot) toyota (dot) com/p/Toyota__/Suspension-Control-Arm-Bumper-Left--Right--Rear/63379294/483410C030 (dot) html

p/n: 48341-0C030

[Taylor95]

Originally Posted by Ecky

Maybe you already know all of this, but here's my understanding and experience:

Cutting the stock springs is an option, but I wouldn't go a full 2 inches. As the springs get shorter, the spring rate goes up, which somewhat helps offset the reduced travel, and it can be a reasonable option if you're not removing much, especially on vehicles with a lot of travel to begin with.

Swapping in a lowering spring is typically a better option because they're usually a lot stiffer, and that prevents slamming the bump stops, which is a LOT harsher than upping the spring rate. The Insight is notorious for slamming the stops in the rear, and putting in stiffer springs really improves the ride harshness. You do, however, have to live with a stiffer ride on a day to day basis.

Changing the spring rate throws off the damper tuning. Depending on how much stiffer the springs get, you may find you start to have oscillations or bouncing in the rear if you don't change the damping as well.

Coilovers are the best of both worlds because (depending on the design) you can keep the full suspension travel while also dropping the ride height, by raising or lowering the lower fork, rather than cutting travel and increasing the spring rate. Most also have adjustable damping rates so you can tune it for the springs. If you want a stiffer spring on a coilover, you can even keep the full travel by adding a helper spring that fills the gap when the vehicle is off the ground.

My experience is that, leaving the rear of the vehicle high often hurts fuel economy the most. Just as an example, the front of my car was a full inch and a third lower than the rear for a little while, and when I finally got around to reducing that to ~3/4" difference (I too keep the rear high for towing), there was a noticeable improvement in both handling and fuel economy.

I found lowering springs for the front (meant for a Tundra), but if the rear could be adjusted, that would definitely be the best solution. I have no idea if that is a feature on my car; I will need to look into that