19.5″ Tires – Revisited

This content has been archived. It may no longer be relevant

Back in July 2016, I installed Michelin XDS2 tires on Vision 81 wheels on my truck. The tires are commercial, 19.5″ tires that have significantly higher load carrying capabilities and stability than offered by conventional passenger truck tires. To that effect, they’ve been excellent and were well worth the money. If all I ever did was tow, and rarely used my truck unloaded, or never longed to leave the pavement, they would be the perfect tire.

However, 19.5″ tires are full of downsides that have slowly become more and more apparent to me.

• They ride rough and jerk you around because they don’t absorb road anomalies. This is due to both sidewall construction (extremely stiff) and high pressure. My rear tires are almost always at or above 90PSI. If not for the Kelderman suspension, they would be unbearable for my wife and uncomfortable for me. Now they’re just somewhat uncomfortable for both of us.
• They’re loud and getting louder.
• 245 tires are narrow, which I find somewhat unappealing, and they track ruts from large trucks quite badly.
• You can’t air them down. They require something like 70PSI just to keep the bead, which is designed differently on half-size tires than passenger tires. This means you can’t reduce pressure to improve ride quality, and means you cannot air down for more traction off pavement.
• Nobody wants to work on them. This didn’t sound like a big issue, but the only places that want to work on these tires are commercial shops who don’t have the proper equipment or finesse to work on aluminum wheels without damaging them. Or at least in my experience. As they age, this does become an issue as they wear and fall out of balance. This also makes them difficult to find, if a replacement is needed.
• The tread compounds are very hard and, while they wear great, that means that you have less overall traction in lots of situations. On a slick boat ramp, for instance, I seem to have a harder time finding traction than trucks running LT tires, regardless of technique. Traction, in general, has gotten quite a bit worse over the last two years, despite a lot of tread remaining.
• They are limited to 75mph, where speed limits around here are 80-85mph.
• TPMS sensors don’t work with them – the signals cut in and out and generally don’t work.
• The selection is extremely limited compared to passenger tires, and they are far more expensive. These cost nearly $500/ea.

I’ve looked numerous times over the last year or so for a light truck wheel and tire combination that would provide the load carrying capacity I need with a decent safety margin left over. With a rear axle weight of approximately 7400lbs, that means I need a tire capacity of 3700lbs, and at least a 10% margin of safety on top of that to address my concerns. That means that each component needs to be rated for 4070lbs.

I’ve seen quite a few discussions on duramaxforum.com about Cooper Discoverer STT Pro tires lately, with good reviews referring to them as a combination of nice ride quality and road manners, good off-road capability, and towing stability. They’re a MT tire which generally would have led me to steer clear of them for towing, but enough reviews have convinced me otherwise. So starting there, I looked up the specs and found that I need a 295/70r18.

The tires are 34.49″ tall, compared to my current 33.60″ tall tires, and 12″ wide compared to my current 9.7″ tires. They’re a little under an inch taller but quite a bit wider, which means I may have to make some adjustments to my suspension to make them fit nicely. Fortunately, I have plenty of room for adjustment there. They have a load carrying capacity of 4080lbs, which is over my target of 4070lbs, though not by much.

Wheels on the other hand, were extremely difficult to find, and it took months for me to stumble across one. The majority of aftermarket 18 or 20″ 8×180 bolt pattern wheels are rated for either 3500, 3525, 3640, or 3700lbs. None of those meet my requirements. The factory 18s (which I never had, since my truck came with 20s) are assumed to be rated for the tires that come on them,  3580lbs. For the longest time, I found no options aside from the oddball 3800lbs wheel above those figures. Last night, looking again, I stumbled upon a wheel with a 4500lbs rating.

That means that the tire, if I were to go with this setup, would be the limiting factor at 4080lbs, providing me with a rear axle capacity of 8160lbs. That’s a good bit short of the 9000lbs that the 19.5″ tires provide me, but still provide a 10% margin of safety even with the heaviest load I carry, and alleviates most or all of the bullet points listed above. The wheel is definitely not one I would normally go for: it has fake beadlocks and only comes in matte black. Black as a color is great, but not on wheels. That’s a common color nowdays, but I think that black is terrible on wheels as they tend to get lost in the tires, especially in dim lighting. Second, I only want beadlocks if I actually have beadlocks – I don’t have much appreciation for fake, non-functional gear like that. Asking around, though, the consensus is that most of my friends think they will look great. And I prefer function over form, so…  I opted to go for it.

I looked all over the Internet for them, but the best deal was close to home, at Discount Tire. In fact, the wheel is backordered everywhere and that is the only place that I could even find them. I ordered them online and will have them delivered to my door, since they don’t have any in stock in Texas (nearest are in St Louis, I believe they said over the phone).

I hate that you can’t try before you buy with things like this – I’m not sure how stable or comfortable the ride will be when towing the RV, which is the ultimate test. But I did speak with someone who runs the truck, with the same size tire, in Cooper S/T Maxx form (which is similar in design, and by the same manufacturer), and a 7440lb rear axle weight on factory 18″ wheels (taking his chances with those), and he claims to be very happy with the setup.

I will have to put them on and go through a little trial period, but if all goes well I will be putting my 19.5″ set on the market to make some of my money back. They have been great for towing and provided me with a lot of confidence and peace of mind when running heavily loaded, but other options are available now that claim to address our needs without all of the gotchas. I hope these work out and I can find a new home for the 19.5s.