4WD Tyre weight; how do they compare?
It’s time to start looking at new tyres for our Dmax, and I’ve started doing a bit of research into the individual tyre weights on a particular tyre size, and the results are quite interesting.
Our Bridgestone Dueler 697‘s are about 60 – 70% worn, but with a trip through the Pilbara coming up in the next few months and a giant tyre shortage in Australia, I think its a good idea to get them on order now, and swap them out prior to leaving.
That, and our novated lease is coming to an end, and I’d much rather purchase the tyres through that, than pay out of my own cash.
Why does tyre weight matter?
In an ideal world, you’d have a tyre that weighs next to nothing with good wear and puncture resistance properties. Unfortunately this doesn’t exist, so you need to look for something that is going to suit you best.
The heavier your tyres, the more fuel you’ll use, the heavier your unsprung weight (and therefore the harder your suspension works) and the more annoying they are to change when you get a flat.
Obviously this is in conjunction with the wheel weight, and you can have hugely heavy 80 series Land Cruiser steel rims, or light weight, solid aluminium wheels that can save you a huge chunk of weight.
Rotational weight does a couple of things. You’ll have a harder time getting going, keeping the same speed and your brakes will have to work harder to pull your vehicle up. In the grand scheme of things I don’t expect too many people to look at tyre weights, but I thought it was fascinating.
For us, we have a bit of additional weight available, but I’m conscious of the increase in fuel consumption and load on the vehicle.
Going from a Toyo Open Country AT2 to a Toyo RT for example is 12% extra rotational weight, or about 10.4kg that comes off our GVM. In terms of work though, you are looking at about the same as adding 42kg of gear into the vehicle and keeping it there full time.
Tyre weights on a 265/75/16 tyre
Going on from the above, we are chasing a 265/75/16 tyre. This is the chosen tyre size for us as it gives us some much needed clearance without totally destroying our fuel economy, torque and power.
Below are some tyre specifications for different tyres in that size:
Toyo AT2 21.4kg, 10 ply rating, 2 carcass plies, 12.7mm tread depth, load rating 123R or 1550kg each.
Toyo RT 24kg, 10 ply, 3 carcass plies, 13mm tread depth, load rating 123Q or 1550kg each.
Toyo MT 26.4kg, 15mm tread depth, load rating 123Q or 1550kg
Bridgestone Dueler 697 LT 12mm tread depth, load rating 123 (1550kg), weight unknown
BFG K02 24.3kg, 11.9mm tread depth, load rating 123Q or 1550kg,
BFG KM3 26.95kg, 14.3mm tread depth, load rating 123Q or 1550kg
Achilles Desert Hawk XMT LT Load rating 1550kg 13.95mm tread. Weight unknown
How much difference is there?
If you look at the Toyo tyre range, you’ll see the difference between the AT2 and Mud Terrain is 5kg per tyre, or that the mud terrain is 23% heavier.
If you run 5 tyres, that’s an extra 25kg of weight, and then if you’ve gone to heavier, aftermarket rims its no wonder your fuel economy changes. If you go up in tyre size, the weight increase is even more, and all of these little things add up to a substantial change in vehicle performance and handling.
So, is 5kg per tyre worth it? Well, that depends on what sort of terrain you want to drive on. We’ve done a post on Mud terrain tyres vs All Terrain tyres, and whilst mud terrains do have some benefits, many people might not ever have a real need for them.
Everything adds up
If you go from a stock wheel and tyre combination (highway terrain and alloy wheel) to a larger mud terrain and aftermarket rim, you are going to add a substantial amount of weight.
A normal tyre (Toyo Open Country U/T – Highway terrain in 245/70/16) is around 15.5kg, which means going to a mud terrain in 265/75/16 is an extra 11kg per tyre.
Double that for a heavy duty steel wheel, and you’ve just added 110kg of extra weight to your 4WD, just from swapping tyres and rims over! For some 4WD’s, that’s nearly 20% of your payload gone, and you’ve hardly changed anything, at least on the surface.
This weight change hurts your GVM, axle weights, payload, fuel economy, braking, acceleration and makes your suspension work harder off road, so choose wisely.
Suitable tyres, with a light weight, decent wheel is the way to go; don’t sacrifice on quality to save weight, but keep it as light as possible too.
After having a big blowout on our camper trailer, I’ve opted for two new Toyo RT’s on the camper trailer, and we’ll run the Bridgestones for one more trip, and then likely upgrade them to Toyo RT’s as well.