2018 Tundra - Suspension

I am just learning about the suspension on my Tundra and suspension in general. I have a Alu-Cabin and everything is stock as far as I know.

My weight fluctuates depending on where and what I'm doing. If I'm taking a long trip, I fill up my 50L water tank and all other camping gear. If I'm taking the dogs to the river, no water and no gear. (will be weighing when I'm in this mode)

Door Sticker:
GVWR: 3265KG / 7200LB
GAWR:

FRT: 1815KG / 4000LB
RR: 1880KG / 4150LB
w/ P275/65R18 Tires
​

I recently weighed it at a CAT scale with about half a tank of water (25L) and most camping gear:
STEER AXLE: 3540, DRIVE AXLE 4100

I'm assuming that I'm close to being overweight and need to figure out what to do.

I'm looking for resources on understanding the suspension system in general (e.g. Suspension for Dummies)and what options I should look at (and maybe some I shouldn't.)

Thanks in advance!

 

You are technically over Payload by 440 lbs, 7200-(3540+4100). You are just under on your rear axle. I don't thin a few hundred pounds over payload is the biggest sin in the world, but maybe could lighten the back end of the camper and move more gear forward off the rear axle if possible.

I would also add either air bags or sumo springs if possible to help your rear leaf springs.

 

Leaving whether or not the truck is over payload weight aside... there is nothing you can do to increase the payload of your truck. You can only enhance the suspension to better support or balance the load.

With an Alu-Cab I would suggest looking at the rear suspension first, and then the front. There are five main options for the rear:

1. Airbags
2. Sumo springs / Timbren bumpstops
3. RAS - Road Active Suspension
4. Add a leaf
5. Upgraded leaf pack designed for extra weight

You're going to find lots of opinions around here on what is the best. If you are looking for something that is adjustable based on your current load, you narrow the field down significantly to Airbags or RAS.

I personally run Airbags with Daystar bag cradles (it lets the suspension full flex without ripping the airbag) paired with an add a leaf for some lift. It's super easy to inflate or deflate the bags with either on board air or a mini pump based on what you are carrying or towing. Simple adjustability in seconds. The positive is that airbags are a tried and true system. Almost every semi truck uses them. The negative is that the suspension can be bouncy.

The other option is RAS. Lots of videos and reviews online, but it's basically adds tension to the leaf springs and holds them in a bowed position. It's adjustable with an impact gun or ratchet, but it's not something that people tend to adjust on the fly. The positive is that it is a great way to reduce squat on the truck and even out a load. They work very, very well. The negative is that it isn't really into quick adjustments.

For the front, the look for a workhorse coilover with a spring rating of at least 600 lbs. Personal opinion, but stay away from brands like King and Fox. They do very well going fast over dirt but with an Alucab you likely aren't doing that. Go stout and reliable with Elka, OME or Bilstein. I run Elkas.

Now if you want to lift at the same time, the front is easy but for the rear I would look at replacing the leaf pack and adding Airbags. The original springs can only go so far and lift blocks are not a good idea with that weight.

Depending on where you are physically located, there are lots of companies or even members here that would show you their setup and options.

Hope that gets you started. There are lots of good suspension posts on this site.

 

Thanks for your reply - very helpful.

 

Appreciated the input - great pointers!

 

Wow, that surprises me that you are at 4100 lbs on the rear axle! I'm kinda scared to get on a CAT scale, but I should do it next time I'm near one...

To give advice regarding suspension I'd need to know how you use your rig. Offroad much or not, and how rugged?

One thing mountainpete didn't mention is tires. LTs will help quite a bit with stability. Based on my experience with airbags, and then a "4 leaf and remove the overload" pack from Boise Spring, I'd recommend springs. The bags tend to be bouncy. A shock upgrade is probably in order as well... you have stock Bilsteins?

Regarding payload, there are many thousands of people way over GVWR (like 2k lbs over, seriously!) on Tundras and Tacomas, and they run them hard offroad and they usually do fine. Just make sensible upgrades to carry the load and I wouldn't worry.

 

How are Elkas reliability ? I had them on 2 (older) race quads. The first set was outstanding before they were sourcing components from China. Did not have that good of an experience on the newer ones. I know it's an apple to orange comparison

 

While I don’t put that many miles on my truck as it currently isn’t a commuter, I have had them for about 6 years with zero issues. The aluminum bodies stand up very well to corrosion.