Pros and Cons of a LONGER wheelbase

[LocalmotionSC]

The benefits of a short wheelbase are pretty clear (1) tighter turning radius (2) better breakover angles (3) more maneuverable, etc etc. My preference in vehicles has always been to opt for the shorter wheelbase when given an option.

However lately I have been questioning that conventional wisdom (at least as it pertains to heavier weight vehicles). What prompted this rethinking was twofold, first I was looking into two different vehicles based on the cutaway E-350 chassis, I noticed that the 158" wheelbase model has almost an extra 1000lbs of payload capacity compared to the 138" wheelbase model. Both are E-350 DRW models. The second factor that is making me think differently about wheelbase is my vague--and possibly incorrect--impression that for onroad highway handling, weight behind the rear axle can be dangerous, or at least detrimental to handling (I believe it can create a 'tail wagging the dog' effect). Finally (and most obviously) a shorter wheelbase (for a given overall length) will create more overhang and negatively effect departure angles.

I should clarify that when I'm discussing short vs long wheelbase vehicles, i'm comparing vehicles with the same overall length but different wheelbases.

So I guess the purpose of this post is to hopefully kick start a discussion about the pros and cons of shorter vs longer wheelbases, that fleshes out some of the performance, technical, and safety tradeoffs.

What are your thoughts? Have you seen any 'best practices' or ideal ratios for on or offroad vehicles? Why would Ford give a longer wheelbase vehicle a marginally higher weight rating?

 

[LocalmotionSC]

This conversation discusses some of the physics as well as first hand impressions on the matter.

 

[Bayou Boy]

On the newer Ram HDs you see the same thing. The Megacab and long bed 3500 SRW have 600# more GVWR than the short bed. 11700# and 12300# for 4th gen and 11800# and 12400# for the 2019.

I went from a 2014 short bed crew to the 2019 Megacab. It rides better on the road with less bucking. However the difference when backing a trailer is way more noticeable than I expected. And it's not like we are going from a TJ to a full size pickup.

 

[85_Ranger4x4]

It is probably a balance thing.

Or they are figuring on a bigger van doing bigger things and it is sprung differently.

 

[Bayou Boy]

It is probably a balance thing.

Or they are figuring on a bigger van doing bigger things and it is sprung differently.

I would say no to the differing springs from my experience with my two trucks. I'd bet on the same year trucks the springs would be the same part numbers between the short and long bed 3500 SRW trucks.

And living in South Louisiana with heavily jointed raised highways going both directions from my town I get a ton of testing on roads that will make a truck buck. The Megacab is night and day better than the short bed was. And that's only like a 10" difference in wheelbase on an already long truck.

 

[billiebob]

Short wheelbase, maneuverability is the big plus. Choppy ride, high speed stability are the big negatives.

Long wheelbase, smooth ride, better stability/capability on steep descents or ascents are 2 big plusses.

When you talk about the same overall length with increased overhangs, at the short wheelbase extreme you have created a low speed vehicle bordering on unsafe at speed. No doubt, no overhang, wheels at the extreme of each corner, you have the most stable platform.... all else equal.

It is all about design and balance for your needs. But a low center of gravity, low roll center should always be a priority regardless of the width, length, wheelbase plus a low moment of inertia. Regardless of the overall weight minimize the weight in front or rear overhangs.

The Ford E series vans have likely claimed more hockey player lives in Canada than anything else. 8 or more passengers and ALL that hockey gear in the excessive rear overhang creates a dangerous vehicle.... especially in winter driving conditions. I'm amazed how well they sell. GM has a far better idea with the wheelbase stretch instead of the increased rear overhang.

Safety is more about where the weight is placed.

 

[billiebob]

This is a cool video.. not quite on topic but demonstrating the need to place the weight in the correct place.

 

[billiebob]

completely off topic but is this the ultimate expedition vehicle

 

[85_Ranger4x4]

My Ranger has the most overhang a Ranger can have, the axle is centered under the 7' long bed.

There is a huge difference on how the truck rides/handles depending on how things are positioned in the bed. Not even all the things have to be moved to make a big difference.

 

[deserteagle56]

I'm amazed how well they sell. GM has a far better idea with the wheelbase stretch instead of the increased rear overhang.

No doubt the GM is more stable. At the same time, that long wheelbase makes it useless off the highway.

I have a picturesque canyon nearby that I like to visit every spring. The road in is rough and rocky with multiple stream crossings and, for lack of a better word, giant "humps" in the road. I can drive my Quigley-converted E-350 in there with no problem. I found to my dismay I cannot take my crew cab long bed Dodge pickup in there. First time I tried I grounded the transfer case hard on one of those humps as the front wheels started down the other side of the hump. Even though the E-350 and the Dodge have about the same clearance to the transfer case, the long wheelbase (poor breakover angle) of the Dodge stop me from driving that road.

 

[billiebob]

It is all about design and balance for your needs.

done

 

[Arctic Taco]

completely off topic but is this the ultimate expedition vehicle

At least the most expensive, and if you are driving on 25’ plus wide dirt and gravel roads, but not on snow it seemed.

 

[Buliwyf]

E450+ chassis cabs, aren't evil whale tail Econoline vans. Econolines are toast. That factory makes Super Duty chassis cab trucks now.

My Ram has a 10' bed. Nearly all of my cargo is at, or forward of, the rear axle. My 8' F350 was filled wall to wall. So the Ram has far more weight resting on the front tires. Front brakes stop better. People forget that saggy rear suspensions wreck a trucks ability to stop.

Longer is stable. Easy to drive on the highway. Especially gravel or snow covered highways.

Greater fuel capacity.

More cargo room.

Longer easier to shim and adjust the rear driveshaft angles. Often a carrier bearing. Amazing how often this is overlooked. Not many YJ owners left in the world?

Possibly more aerodynamic. F1 race cars are record breaking long, to reduce drag and increase top speed. Because they are stipulated to use very lame engines.

Smoother ride. Chances are that the Rams above, used stiffer springs to get that extra capacity, and nobody complained, because long trucks ride better.

 

[Bayou Boy]

Smoother ride. Chances are that the Rams above, used stiffer springs to get that extra capacity, and nobody complained, because long trucks ride better.

The axle ratings are the same on the different wheelbase Rams. More bed weight can be transfered to the front axle on the longer trucks, like you explained. That's why the GVWR is higher. It's the same springs.