In researching trikes a bit, I happened to stumble across a Cycle World review of a 2020 TriGlide, and noted that its rear wheels and tires were (and still are at 205/65-15 for 2024) distinctly different from those on my 2023 RG3, being 205/65-15 versus 215/45-18 on my 2023 RG3

Those triGlide tires are each 10mm = 0.39" narrower than on my RG3, and their sidewall height of 133mm is WAY higher than the 96.75mm sidewall height on my RG3.

The 15" wheels on that 2020 model year TriGlide versus the 18" wheels on my RG3, coupled with the tire size difference, nevertheless combine to result in the TriGlide's overall wheel/tire assembly being virtually identical at about 25.5" diameter compared to the 25.6 on my 2023 RG3

Obvious conclusions based on just these differences:

- The lower sidewall height on my RG3 should result in a significantly stiffer ride than on the TriGlide

- The narrower 2020 TriGlide tires result in the outside dimension between left and right outer tire sidewalls of about 51 or 52 inches, mean that it is possible (not necessarily wise) to load a 2020 TriGlide onto a 50 or 51 inch wide table motorcycle / ATV lift with side extensions to lift it, but it is NOT possible to load my 2023 RG3 onto such a lift because ITS outside dimension between left and right outer tire sidewalls is just over 54 inches!

- The wider tires on the 2023 RG3 make the RG3 look notably wider

- The 5% wider tire footprint on the RG3 probably gives it just a bit more rear tire traction for cornering

- The stiffer tire sidewalls on the RG3 probably enable it to corner just a bit more aggressively than the TriGlide, all other things being equal

- The 2023 RG3 larger 18" wheels and narrower tire sidewalls to my eye look better than the 2020 TriGlide 15" wheels and tires

When you start looking at DETAILS, you can see how HD engineers tuned BOTH the performance and appearance of the 2 models differently, to support in the case of the TriGlide a long distance touring usage, versus the RG3's "sporting" usage.

Of course there are other differences in other components as well, like the sound system, the storage capacity, the engine cooling, the body shape, and body details (compare the front and rear fenders for example!), etc. But these are much more obvious than the wheel and tire differences are to most observers and most buyers.

Then there is also the 26 psi versus 20 to 22 psi tire pressure controversy and its legitimately questionable Ford Explorer caused history, and the trikes' tire psi monitoring system not allowing changing the "target" psi, resulting in a perpetual tire psi warning light if you choose to go the 20 to 22 psi route for good reasons.

Also, hopefully you have noticed that on all trikes, and also on at least some 2-wheel HDs (my 2023 Breakout), the OEM rear tires are radial but the OEM front is bias ply.

Details, details . . .

Trikes are not as straightforward as first casual looks might imply.

Jim G

 

Good info Jim. Thanks. Told a friend who purchased a RG3 and was complaining about poor ride quality about lowering the rear tire pressure. His dealer dissuaded him from doing this saying because of the lower profile on the RG3 tires the lower pressure might allow the rim to be damaged easier than it would on a tri-glide with the taller tires with more sidewall. Sounds reasonable in theory but I am not sure in the 'real world' it would be a concern.

 

These 215/45-18R rear tires on the trike are CAR tires, in a size that is often used on cars weighing 4000 lb or more, which means 1000 lb static loadingper wheel with the car empty, maybe add 800 lb for 4 passengers in winter clothing, so 4800 lb static loading, and then you have 1200 lb per tire static, and much more than that in dynamic loading of course.

On an RG3, you have about 780 lb static load on the REAR end of the trike (about 380 lb on the front). Now let's look at an HD media photo of the RG3 for rider, passenger, and trunk loaing:



Add 400 lb for passengers: Rider is about 70% on the rear wheels = 140 lb, and pasenger is maybe 90% on the rear wheels = 180 lb.
The trunk is rated by HD for a maximum of 60 lb or so, and is 100% on the rear axle,
So we add up the total static loading on the rear axle: 780 + 140 + 180 +60 = 1160 lb.
Divide by 2 because this total rear weight is on TWO tires, so 580 lb per tire.

The cars can run at 26 psi. PLUS, after the Explorer public ifasco, the tire manufacturers and auto manufacturers now assume that the car occupants are ALSO going to ovelroad their trunk and maybe even have a roof cargo container or kayak or bicycles on the roof, and might also fill the back seat with stuff on a long trip or when moving house!

The trike's static loading is 580 lb per tire versus the car's 1200 forseeable lb plus unknown add-on weights.

And we need 26 psi just like the cars??? That's hard to believe. I think maybe someone should question that. I thuk it is possible that HD is simply applying the "26 psi minimum rule" that the tire industry fabricated to protect SUV owners who like to overload without even thinking about it.

And since Kevin at DK Custom has been running his a lot lower than 26 psi, since 2014, without apparent issues, and with excellent tire tread wear, maybe we have perhaps been misled by manufacturers eager to avoid any possibility of product liability even when a user is being stupid?

Jim G

 

Another sensible test calculation to apply is this:

The static load on each tire = 580 lb.

The recommended psi = 26

So, 580 / 26 = 22.3 square inches of tire contact with the pavement.

But the RG3 tires have a nominal width of 215mm = 8.5 inches

So, the 8.5 inch wide contact patch with the pavement becomes 22.3 / 8.5 = 2.6 inches in LENGTH.

That's a REALLY small contact patch. Remember, the cars, with each tire carring more than DOUBLE the weight being carried on the trike, at the same 26 psi pressure, have contact patches that are more than double that length. I would worry that at 26 psi, the contact patch is too small and encourages loss of traction over bumps.

Just sayin'

Jim G

 

There is a 3 video series on Trike Heights, and how they are affected by the different wheels and tires. The first in the series can be seen below.

AND below that is a video on the ridiculous Government intervention in PSI on the Trikes. Here is a LINK to what the PSI should be, and Why, according to the company that designed the Harley Trikes.

To throw in, for good measure, here is a LINK to how height of the rear of the trike affects rake and trail, and how that affects the Trikes handling.







Kevin