Light truck wheel size upgrade

Hi guys, got a small dyna truck, 15' wheels front but anyhow it got 13' wheels down the back, just want to know if its ok to upgrade to 15' wheels? Thanks for any advices.

sure but weight rating will change. its 13 inch dualies isn't it? -also if you go to 15 where ya gonna get low profile truck tyres?

Yea, 13" to 15" would normally be a massive difference, THEN theres the diff gearing & wheel stud pattern issues

Unless you have a special reason too I wouldn't

Such vehicles are set up that way on purpose. Small diameter tires in the rear allows the flat deck or box (without wheel wells) to be installed lower to the ground for easier loading, lower cog and more height capacity before height limits are reached.

Dualies on the rear allow for enough weight capacity even with the tiny tires. Can't have dualies on the front axle, and no height issues are this location, so larger tires with a higher load rating are used. (Plus things like driver comfort, and fitting over larger front breaks factor bigger wheels & tires here.)

Wheel size is basically selected to suit the required tire size, giving a decent sidewall. (In cars aesthetics is a main consideration, less so in trucks)

General recommendation is not to change tire diameter by more than 5%. Increased beyond this, things like different ratios, spedo calibration etc. Become an issue.

As such to increase wheel you will either need to find a super narrow wheel and low profile tire combo for dualy use. Or a conversion to single rear tires with a low profile tire with really high load rating. Personally wouldn't want either unless a specific use case. Low profile tires are more prone to damage and give a worse ride.

Or you go for a much larger diameter tire on the rear and rework the suspension, headlights, deck height, different ratio to suit it. Note if the truck has absolutely or stability control It can have issues if the diameter of tires on one axle are changed.

Personally sounds like too much effort. Live with the current configuration or sell the truck and get something with the configuration you want.

here is what i have done on my mb140 i put vw amarock tyres on front drive axle. before i had desert dualers low and wide now they are narrow and tall. Benefits are the larger in diamater a tyre the longer it takes to travel 1km. old tyre was 104kph was 100k with new setup 99kph =100 now. so yippy i am finalyl saving 1km per 100 ruc while i overpaid for years on other tyres.
That would be a good reason to switch tyres so your hubometer dont rips you off no more. Needs a lot of thinking . i went to this set up because the dualers where to wide for my rear . now the tyres could fit front and rear if need be on my van.

+1 s_nz sums it up well.
the whole body is built around that size tire.
if your changing body anyway, it might be possible to change it by replacing it with the rear end off the 15" wheel version.
you would have to double check the brakes, hopefully the whole rear end will have the bigger brakes required but need to check master cylinder is suitable.
this all will require inspection and certification.
frankly, cheaper and easier to just go buy the big wheel version.

Your last line is the key point. If there is a pressing need for a different wheel size, that would be the easyist route. Numerous small trucks (incl the Dyna) are available with matching frount & rear wheel sizes. If no pressing need, enjoy the lower deck / box height.

The lower deck height is a selling point for many especially if the vehicle will be manually loaded and unloaded. Cheaper for the manufacture to ditch the Dulles, and just fit a single bigger tire on the rear axle to get the right payload ability. No need for two spare tire sizes then too.

My guess is that the OP wants same size wheel/tyres front to rear. That aint gonna happen. Even the single wheel rear setup in the Dyna is 15 front and 14 rear (very wide rear tyre) But it also has a significantly lower weight rating.

Thanks guys for the info, I will stay with my tiny 13' to save the hassle