Question: How much spare tire can you fit under your truck?
Answer: It depends.
This post is about squeezing a large (35.4-inches) tire into the stock location on a late-model, fourth-generation, Dodge Ram Cummins pickup.
Both my Ram 2500 trucks (2014 and 2017) have had the tailpipe heat shield removed to facilitate winching a much larger tire into the factory spot. Obviously a bigger tire sits closer to the tailpipe. Only you can decide if it’s too close for you and your application. This Cooper Tires STT PRO is only about one-inch from the tailpipe; close!
For several years I have carried oversized rubber in the factory location on my fourth-generation Ram/Cummins trucks, mostly tires that were 34.8-inches tall. The 295/65R20 Cooper Discoverer STT PRO is substantially taller.
My 2017 has less room overall than my 2014, as the factory trailer hitch receiver is still in place. (It was removed on the 2014.) There are also steel plates on the inside of the frame to mount the Hillsboro 2000-Series aluminum flatbed. The 3/8-inch plates, one on each side, consume 0.75-inches.
There are advantages to choosing 35-inch or smaller tires on late-model, heavy-duty trucks instead of the popular 37-inch versions, particularly if they will fit in the factory spare location. These include, but are not limited to, not needing an additional tire carrier or pushing a truck camper further aft to fit a spare in front of the camper (which increases rear-overhang, tail-swing, and impacts weight distribution). Unless your rig is geared low—and most new vehicles have tall gearing—the taller overall gearing that results from fitting larger diameter tires is often a negative, as it results in less torque at the wheels.
Many should ask themselves if they really need the extra clearance provided by 37-inch rubber, or are they just following the crowd, and potentially making unnecessary compromises. There are positives and negatives for nearly every modification and upgrade choice. Generally we need to give something to get something. Everyone should decide for themselves if the juice is worth the squeeze.
This video introduces using Centramatic 400-409 balancers designed for DRW trucks with 16-inch wheels, on SRW pickups with 20-inch wheels. These balancers have 16-ounces of balancing media!
Article about the possible performance advantages of 20-inch wheels over 18- or 17-inch wheels on heavy outfits: 20-inch vs. 18-inch Wheels and Tires
When the Toyo Open Country C/T was initially introduced it was only available in Canada. A few years ago, when that changed, it moved to the top of my must try list. Commercial traction or hybrid designs are my favorite type of tread, and the C/T might be the best, slowest-wearing design I’ve used on any truck in several years; maybe ever.
Mount, balance, and tracking
Because the Open Country C/T is an on/off-road commercial-grade tire, there are fewer sizes offered than other Toyos like the Toyo A/ T II. However, there are still six 16-inch, seven 17-inch, five 18-inch, and seven 20-inch sizes available.
For this evaluation I mounted 35×12.50R17 on forged aluminum OEM Ram Power Wagon wheels. They required very little weight to balance, typical for Toyos, and ran smoothly down the highway at all speeds.
Initially mounted my 2014 crew cab, which has an SPC offset right ball joint to counteract treads that pull to the right, the C/T would drift just slightly to the left after a few seconds with no hands on the steering wheel, depending on the road crown. (To be perfectly clear, this is because of the offset ball joint and caster settings, not a characteristic of the tires, the C/T does not appear to pull right or left, they are neutral.) On the 2017 Ram 2500 regular cab with Hallmark flatbed camper, the C/T track perfectly straight for several seconds on flat roadways. They were a great match for the outfit, and where I decided to keep them for this evaluation.
General traction and performance
The C/Ts saw a little of most terrains, including snow, packed dirt, gravel, rock and plenty of pavement. Deep off-highway mud, snow, and deep sand were not experienced; a 10,000-pound camper outfit is less happy on these surfaces, so I only drive on them when necessary. However, with the good void-ratio and siping this tread offers, I’m confident the C/T would perform as well or better than similar commercial-traction designs.
Many modern tires perform well in moderate on-highway or off-highway snow, and this was true with the C/T. However, the mountain snowflake severe winter rating provides extra assurance in wet conditions, and I would pick the C/T over many hybrid or all-terrain designs for winter service. Obviously they are unlikely to perform as well as a dedicated winter tire, but those designs are less versatile on heavily-loaded trucks and rarely offered in larger sizes.
The Open Country C/T is quiet for the void it offers, and no louder than the Toyo R/T or A/T II Xtreme with which I am familiar in similar sizes. I’ve recommended the C/T to many of my readers, including a professional photographer and adventurer who lives in Jackson, Wyoming. He has been impressed with their snow capabilities. Another guy lives full-time in his heavy truck camper and uses them.
Wear close-ups
You can see a small amount the feathering on the outer lug sipes. For nearly 6,000 miles without a rotation, this minor visible wear was impressive and not concerning. Appropriate rotations will true-up the tread.
Phenomenal Longevity
As my video assessment and testimonial enthusiastically shares, I am most impressed with the slow rate-of-wear on these Toyo Open Country C/T, better than any other tread in years, maybe ever.
The 4,400 miles per 1/32 of depth is exceptional, particularly for such a heavily-loaded, diesel, truck camper outfit. Was the slow treadwear due to a higher than typical percentage of highway miles? Possibly, although my outfit is not a daily driver and routinely sees many more long-distance travel miles than city driving. Double the mileage of most tires I’ve run on diesel trucks, and still 50-percent more than other standouts is nothing short of phenomenal!
The C/Ts were removed from service only to begin another review, but I’d like to run them again soon, preferably in an 18-inch or 20-inch size with a higher load-index that’s better suited to my heavy camper. The 35×12.50R17 was chosen because I wanted a 35-inch size, and I already had the wheels. At the time I was adamantly against 20-inch tires because the shorter sidewalls offer less flex off-pavement. Though shorter, less flexible sidewalls can be a huge a positive for overall camper stability and handling. My opinion has softened, as long as the tire is tall enough that there’s adequate sidewall.
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James Langan
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My flatbed camper outfit works well, but I’m always tinkering, fine-tuning, and looking for small improvements. I’m still using and loving the TufTruck and Timbren springs, just also want to inflate these air springs again which have been sitting dormant for months.
Essentially the same Air Lift product has been on my 2006 4Runner for over a decade (they’ve been flawless, after another brand failed twice). Also on my 2014 Ram 2500 since new, including up to the Canadian Arctic Ocean a few years ago. That’s a good record, so I’ll give this one failure a pass.
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James Langan
Copyright James Langan/RoadTraveler. All Rights Reserved
Reader slangheld asked my opinion about Ram 1500 rear suspension options after seeing one of my Ram 2500 heavy-duty rear suspension post photos showing TufTruck, Timbren, and Air Lift aftermarket springs.
Question:
I’m confused, and I’ve considered all of these options for my 1500 (Ram). I’m leaning towards the Air Lift 1000 for the ease of install, maintaining unloaded ride quality, and price. Any opinions?
I asked:
Give me more info… what is your load?
Load and use details:
I’m pulling a bumper-pull camper (trailer). Tongue weight is close to 900 pounds, and I figure my 1,471-pound payload is close to the maximum. I probably take six, two-to-four hour trips per year. The truck might get another six heavy loads each year doing stuff. The rest is street or highway driving.
Reply, HD Ram 1500 springs:
There’s nothing wrong with the Air Lift 1000 drop-in springs, and I agree that the ease of installation and low price, along with retaining the soft factory ride when unloaded are pluses. Possible negatives with air suspension can include leaks, and sometimes a bouncy ride, deepening on the rest of the chassis setup and suspension. Air Lift’s Universal 1000 springs were the first heavy-duty spring upgrade to the rear of both my 2014 and 2017 Ram 2500s, worked quite well, and it’s a simple and inexpensive place to start. The pair on my 2014 crew cab have remained leak-free, however I do have a leak somewhere on my 2017. That truck has had the springs installed and removed a couple times, where the 2014 has remained plumbed.
TufTruck rear coils for my 2500 are designed to add about 500 pounds of additional carrying capacity, which is really not that much. I would love it if they made an extra-heavy-duty set for my application. Looking at TufTruck’s site I was surprised to learn that they make four different rear coil options for the late model Ram 1500s. Their variable-rate TTC-1223V is presumably their softest-riding spring when unloaded. It’s nice to have choices, and they are all quite inexpensive, from $215 to $270. Rear coil spring installation is so much easier than leaf springs. Like the Timbrens below, the TufTruck coils are never going to leak and should be maintenance-free.
The Timbren rubber auxiliary springs seem to work impressively well with my truck camper, both the DR2500D regular-duty set I installed June 2019, and the DRTT3500E severe service springs added six months later. With my heavy truck camper the Timbrens are constantly loaded, same as they were on my 2011 Toyota Tundra with a slide-in Four Wheel Camper. On trucks that only see occasional loading, Timbrens are set-up to only engage after a load is added. I’m considering putting the DR2500D springs on my 2014 crew cab that no longer hauls a truck camper, and sees more typical, mixed use. Installing the Timbrens is arguably even easier than the Air Lift 1000s. There are no airlines to run or leak, though they are more expensive and theoretically not as adjustable. Theoretically because it’s likely that you would simply inflate the Air Lift 1000 to their maximum 35 psi when loaded, and then reduce them to the minimum 5 psi when not hauling.
If I owned a Ram 1500, depending on my loads, I am guessing that I would try a pair of TufTruck coils, which I’d possibly augment with either Timbren or Air Lift 1000 auxiliary springs.
There are a lot of good options and products, but it is sometimes a crapshoot of where to start or what will work best on your outfit for your needs. Often some tinkering is required to get things exactly where you want.
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James Langan
Copyright James Langan/RoadTraveler. All Rights Reserved