2015 4x4 Challenge: Going Slow

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By G.R. Whale

We know there's a lot of engineering that goes into a making a good 4x4 pickup truck, but for this Challenge we decided to focus on our two contenders' capabilities off the pavement, first looking at their "slow-go" talents and then at their "fast-go" off-road talents.

On paper, the 2015 Ram 1500 Rebel's impressive crawl ratio (1st gear multiplied by low range multiplied by axle gear) of 48.7:1 is impressive, but we don't drive on paper. While finessing our way up obstacles in 4-Low, we found the Rebel's throttle response demanded a delicate touch. It needed more restraint and sensitivity than the 2015 Toyota Tundra TRD Pro, which has a crawl ratio of 37.8:1. In fact, in certain situations when in low range, the Rebel got plenty of wheel speed but then upshifted a little early, bogged a bit, then downshifted again and repeated the cycle enough that it had one of our drivers thumb-shifting with the manual control on the steering wheel to get a smoother drive. In comparison, the Tundra's throttle response and gear-holding seemed more suited to the off-road fun we were having; it sauntered steadily in almost all climbing and sand-running situations.

During our steep downhill descents, we put both competitors in 4-Low and 1st gear and released the brake pedal to see what kind of "holding" power the transmission would create. Neither truck had a hill descent feature, so this is where we'd likely see how well the transmission's control module could predict what we needed. The Tundra slowly rolled up to 3,800 rpm, moving to an indicated 9 mph, and then leveled off on the steepest part of the long hill descent.

The Rebel, on the other hand, rolled up to 5,500 rpm on the same decline, moving at an indicated 10 mph, and continued to accelerate. Fearing an auto upshift, we applied the brakes to slow down. On our second attempt, we saw 5,800 rpms, so we braked again.

The Tundra made us feel more comfortable on steep descents, giving us more confidence. We can't say whether this is a result of the Tundra's engine construction, valve timing available from separate intake/exhaust cams, programming, torque converter or some combination thereof.

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Crawling through deep, rutted trails, the Tundra seemed to offer better suspension articulation, especially when looking at rear-axle droop. We measured more than 16 inches from fender to tire during one flex, despite a calculated payload rating that is nearly 40 percent higher than the Rebel's. However, we found the Rebel had a good limited-slip differential (our tester had only 2,400 miles on the odometer), much smoother electronic traction control, and it was less prone to rear wheel hop than the Tundra.

On moderately slippery surfaces, the Tundra's tires with their more laterally oriented tread blocking had an easier time finding something to grab, while the Rebel required more momentum in situations where the axle could not droop enough to give the tire treads enough grip.

We should note the Rebel's as-delivered tire pressures of 55/45 pounds per square inch (front/rear) were considerably higher than Tundra's 33/33, so the Tundra's tires seemed to wrap around rocky obstacles better, but that didn't hurt the ride on hard pavement. With a load capacity nearing 3,200 pounds per tire, none of the treads required anywhere near maximum pressure.

With the Rebel's air suspension lifted to its tallest off-road setting, both trucks seemed to scrape and bang obstacles similarly, with the Tundra's front tow hooks and the Rebel's bumpers and center skid plate taking the brunt of the more significant hits. Surprisingly, we never dinged any tailpipes or ripped off mud flaps.

The Rebel's big advantage in this 4x4 slow-go contest is a 5-foot tighter turning circle; you can feel the front wheels beneath your feet when navigating a tight trail. The Tundra's front tires feel like they're quite a ways out in front of you. That meant more Tundra steering input (and effort), while the Rebel's electric assist felt a touch better than Toyota's hydraulic assist.

Cars.com photos by Evan Sears

 

Overview | Fuel Economy | Test Measurements | Going Slow | Going Fast | What the Judges Said | Results

 

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Comments

The absence of the Power Wagon makes this test kinda pointless.

@ Clint

Except for the part where it clearly states that they've picked the two newest half-ton off-road entries as the test.

I've never experienced a website that has so few individuals that actually read the articles and then comprehend them. Most are just looking for their own trigger words.

The absence of the Power Wagon and Raptor make this test extremely valid, as there is relatively little market for the two extremes but a much larger market for machines that can perform all duties well, even if not the best at any one capability.

That said, I have a question on one paragraph in this specific test:
"We should note the Rebel's as-delivered tire pressures of 55/45 pounds per square inch (front/rear) were considerably higher than Tundra's 33/33, so the Tundra's tires seemed to wrap around rocky obstacles better, but that didn't hurt the ride on hard pavement."

Now, as I read this I have to wonder why, if at all, they raised the tire pressure back up to factory specs when in the high-speed test they made it clear they aired down the tires to about 25psi on both trucks. This could have had a deleterious effect on their trail handling and changed the outcome of the slow-speed test significantly.

That said, the Toyota SEEMS the better truck here in many ways, though one factor that is more important to me is the turning radius, where the Rebel proved notably superior. Both on-road and off, I've seen where a tighter turning radius simply helps in maneuvering around obstacles and onto and off of streets and highways. I'm always amazed at why anyone is willing to buy a full-sized truck when even with a three-lane-wide area to perform a U-turn (legal at some intersections where I live) a full-sized truck has to stop and back up to avoid riding up onto the curb. Meanwhile, all three of my vehicles can perform the same maneuver in less than two lanes' width.

Objectively, I'd have to give the Tundra credit for apparently better capability in many ways (tire question notwithstanding) but the Rebel takes the subjective lead for maneuvering.

Everyone take a good look at the size of the suspension components on both trucks, ball joints, steering arms,hardware, heck -even the material the lower A arm is made out of..... I know which one I have my money on!

Tire pressure and tire compound play a huge roll in off road performance. Softer tire compound and lower pressure are huge in ride and traction. That's why they make bead locks. For very low air pressure not to spin the tire off the rim.



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