Winter driving and adding weight in the bed of a 4x4 pickup?

[Vulnox]

True true. I'm not so much worried about acceleration but rather want to make sure I can stop in time to avoid an accident. That being said, there are some pretty good inclines in this city and I've had bad experiences not being able to make it to the top with my RWD Charger back in the day (even with good winter tires on). Granted, this F-150 is 4WD and all but having a light back end and a lot of torque (hello fishtails!) brings back nasty memories. Hence my original question about adding weight back there.

Yeah, I think adding a bit of weight is fine. I add 200lbs. While weight hurts stopping distance, 200lbs isn't really different than having a 200lb guy in your passenger seat, heck if might be better with more weight on the rear axle like we were discussing. I think you start to see diminishing returns at 500lbs or so. That's a lot of weight and probably where the stopping gets sketchy.

I am sure someone has done the research on it, but I think you have the right idea already.

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[Lippy]

I live in NorCal and it doesn’t snow where I live, but we go up to Tahoe often, where conditions can be extreme. So I’m thinking of jetting my Pirelli ATN all seasons and getting some three peak tires, like Cooper Discoverer 4s, and just using them all year around. Not sure if I’ll put weight in the back. I’ll see how it goes.

 

[Kanuck]

I use to work for a weight scale company and carried weights in the bed. I had a 2x4 across the front and back of the wheel wells with short pieces running long side the wheel wells screwed to the front and rear pieces... If that makes any sense. Basically made a box between the wheel wells and it could not slide around.

 

[Pedaldude]

No, do NOT put it as far back as possible. You want the weight over the axle, not against the tailgate. ...Please do not follow that advice. ...Loading over the axle with result in the most rear weight with almost no weight taken off the front. This is middle school physics stuff.

Winter tires are your best friend if concerned with traction. Because just adding weight also increases your stopping distance...

You kind of get the physics of this. I will try and explain where some of your understanding is incorrect.

Static weight balance and dynamic weight balance are two different things. When the truck is at rest, there is one load on each tire that is rarely seen again as soon as you start moving.

Since each tire is the same size, each tire will ideally be tasked with an equal amount of work in the form of traction.

You can change that balance significantly without adding or removing any weight at all to the truck. Just removing the rear spacer blocks between the axle will transfer weight from the front axle onto the rear axle and improve the rear traction. Racers call this corner balancing or weight-jacking and it's done by manipulating the heights of the individual corners of the vehicle. No weight is added or subtracted, though sometimes heavier items like lead acid batteries will be relocated.

Every tire will have an ideal load and inflation pressure for delivery of maximum traction. Unfortunately, this also usually changes due to conditions. Dry traction, wet traction and ice/snow/mud can be so different; that specialized tires are created for specialized conditions, which is why winter tires can be so much more effective. Everything else being equal though, you will always have maximum traction when you are at the ideal load for each tire.

This ideal load changes dynamically along with the weight transfer of the vehicle, which is why driving smoothly in the snow and rain is so much more important and easier to notice, because of the lower available traction. Manufacturers will sometimes even publish the data and they get it from crazy amounts of testing and you may have seen the glass panels that they would put into test tracks that they used to record the tire patch on cars driving through wet surfaces in old TV commercials.

In this graph, it shows vertical load influence tractive force with diminishing returns. So while moving the weight off the front axle toward the rear may reduce the tractive force available to the front tires, it would increase the total available traction to the vehicle.

Putting weight directly over the rear axle will remove weight from the front axle the same as if you simply lowered the rear spring height without adding weight. The only way to add weight without significantly impacting the front axle weight is to add it near the center of gravity of the truck.

By adding weight behind the rear axle you can achieve the same balance as putting weight directly over the rear axle without using as much weight.

Another entirely different phenomena that you can use to your advantage by having the weight distributed behind the axle (and in front of the front axle) is to increase the moment of inertia of the vehicle and increase its resistance to spinning:

https://en.wikipedia.org/wiki/Moment_of_inertia

Since most people are driving around crew cab trucks, which already have an extra amount of weight biased toward the rear, I would expect that there wouldn't be a huge amount of difference but I am kind of curious now how much of an improvement in braking distance any of the methods mentioned would be in low traction situations.

 

[SumGuy]

Get a dedicated set of snow tires!

 

[KartRacer25]

My 2 cents (recovering New Englander in SoCal):
1. Get good tires, E rated are heavy. I think the OEM Hankooks are decent in the dry otherwise great for a dumpster fire.
2. I ordered spray in liner and retractable cover, also to add weight to rear. LineX is heavier than OEM. You may also get factory bed divider that might fit with swing out boxes, I think someone did this here. I also put my heavy recovery gear in a giant duffle bag I ordered on Amazon and strapped in front of bed. Tools under back seat. A local race shop can bolt on some cheep lead plates too, just must be done safely. And they should have 4 scales to balance the truck out. Or put lead dive weights in boxes, I recommend the soft pellet bags. Also shocks can help rear hop and twist.
Like Pedaldude said too removing block will reduce some rake and add balance to the force. You can also do a chalk test in dry and stager the pressures to perfect the contact patch and balance 4 corners. Then sign up for 5 day O'Neil Rally course in winter, that's were our special forces train. https://teamoneil.com/
There are civilian Canadian version available, Ontario etc.
Practice at and over the limits accelerating, turning and braking, with your truck in a wet then snow then ice filled parking lot, very helpful and at the least very fun.

All good gear/training to get that also help rear end etc.
Then go enjoy, drive like a pro and help others who get stuck.

 

[RidingHighNCO]

If you want to add weight to the rear axle, put it as far back as possible to take advantage of leverage. If anyone has any doubts, stand on the rear bumper and measure how much the distance from the ground and trailer hitch is, then stand between the wheel wells and take the same measurement.

I drove my first truck in Northeast winters until it rusted into oblivion, it was a 4x4 and was perfectly fine without any ballast but once I was on a road with slick mud and couldn't get enough traction to move forward without spinning my inside rear wheel. I grabbed a 90-100 pound flat boulder and placed it on the open tailgate and it was just enough to get traction so I could get to pavement.

I've only driven twice in Montreal during winter and the roads get pretty bad, I think that some ballast might be a good idea, since you're going to want as much of a traction advantage as possible.

Unless you have the AC power outlets, there are ribbed pockets to slide 2X lumber into as dividers, which should hold a few sandbags as long as they are snug.

Here are some pictures that I found with a quick search:

If you have the outlets in the way, there are also screw out and ratcheting cargo bars for securing stuff in empty beds:

Good luck and enjoy your truck!

Technically you are creating a pivot around your rear axial and even so it’s small you are reducing load at your front axial. The best location for added mass in your truck bed is directly over the rear axial.

 

[Pedaldude]

Technically you are creating a pivot around your rear axial and even so it’s small you are reducing load at your front axial. The best location for added mass in your truck bed is directly over the rear axial.

Read post #19, the tire doesn't care where the weight is coming from to an extent. Placing the weight in the bed behind the rear axle creates a lever arm, so that you don't need to add as much weight. Since the front and rear axles are both sprung; depending on suspension geometry and spring rates, the truck will pivot around a virtual point between the two axles.

Even adding weight to the bed directly over the rear axle will transfer weight off the front axle.

Even lowering the rear suspension without adding any weight will transfer weight from the front axle to the rear axle.

The only way to add weight directly to the rear axle without redistributing weight from the front axle is by adding the weight directly to unsprung mass of the rear axle housing.

Redistributing weight from the front axle isn't a bad thing on a pickup truck, as there's already too much weight on the front axle.

Having equal weight distribution between front and rear axles is important because the traction available to the tires is not linear with vertical load.

 

[Stubblejumper]

Having driven pickups for 45 years, where we do get real winter, as in -40, where tires get very hard, I don't add weight, good tires are the best improvement you can make to the vehicle, but proper driving techniques , are what really matters.

 

[notabot]

However, is adding weight useful or recommended when driving a 4x4 which is going to be driven all winter in 4Auto (AWD basically)?

Nope. Weighting the bed is just a huge bandaid for 2WD and part time 4WD pickups.

AWD for the win! Leave the bed free for stuff and don't carry around unnecessary weight.

 

[BigBluegen14]

Don't have any experience (yet) but lots of good info here. Also nice to meet a fellow MTL F150 owner.

 

[Kanuck]

Don't have any experience (yet) but lots of good info here. Also nice to meet a fellow MTL F150 owner.

Welcome..where you out of?

 

[BigBluegen14]

Welcome..where you out of?

Montreal like the OP. Should get my rig towards the end of Nov. Just in time to learn how to drive a pickup in Canadian winter haha. ?

 

[blkZ28spt]

This will be my very first winter driving a pickup truck. I have a 2021 F-150 Platinum (4x4 with 4Auto as well) and live in Montreal. We have real winters up here, I'll tell you that much.

I understand the logic behind adding weight to the back of a 2WD pickup truck in the winter to help the rear wheels get traction. It all makes sense. However, is adding weight useful or recommended when driving a 4x4 which is going to be driven all winter in 4Auto (AWD basically), or 4Hi in the worst conditions? Would doing so be helpful or detrimental (or make no difference at all other than hurt fuel economy)?

Put it in 4-Auto, if it's bad change drive modes to the appropriate one, use good tires (3 peak mountain snowflake minimum), you'll be golden

 

[Kliza]

Fully agree, I only added weight when I was drive 2WD.

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