Changing trailer studs

Changing the studs out is relatively straight forward, but a bit dirty.

Take the wheel off, and if there is room behind the hub hold a large lump of metal next to the back of the stud to adsorb some of the impact and knock the stud out with a hammer. Put the new stud in from the back, wiggle it a bit to get the splines into the marks left from the old one, put a stack of washers on the threaded and then use a wheel nut to pull the stud through the hub.

On a drum/disc its basically the same, you just have to get the drum/disk off first.

If you can get nuts to fit the trailer studs, stick them in a bag and stash them somewhere safe, then that will be the cheapest and easiest solution.
Standardising the studs front to rear would be the better option, but if you want to run steel wheels with the alloy option, then you will still need the bag of nuts.
Standardising the wheels front to rear will leave you with 1 nut type for the lot, but $$.

For the price of a dozen studs and work involved, you'll probably find it cheaper and easier to just buy a whole new hub and bearing. I've found that a hub with bearings isn't much more than just buying the bearings alone. And while your fiddling around with them at least you know the bearings are good.

Tony

Suitcase
I have a Dmax which is same as the Colorado which were made after the RA7 Rodeo. All the same and are METRIC. Toyota uses metric too.
Your van., made by an Aussie and has probably fitted Imperial studs to the hub.
The thread dia and pitch of thread, the coarseness or fineness, may be different to the Prado metric.
Matching the wheel stud threads is MUCH harder to do than carrying a few spare wheel nuts, just in case. Not worth changing the studs. As long as they hold the wheels on is all that matters, you never see them while driving and passers by can't tell.
As long as the thread is long enough I would not bother to try and change them.
If in good condition they will be seated tight in the hub anyway, replacements are not as tight if similar knurling/splines to OE are used.
Will replacement Prado or similar, fit securely into your hub. Lots of people just buy some, they look close, and force them in, ie press fit.

With alloy wheel, the nuts must suit of course, but as long as you have 1 dia of stud as the thread engagement you are legal. The Isuzu,RA7 is deceptive because with the nuts which suit the alloys wheel seem to not have enough thread through the nut, but if measured there is more than 1 thread dia engagement. Can't get any stronger or more holding power/clamping force.

A bit of confusion in your ask as the studs and the wheels really have nothing to do with each other.
Do you know exactly what thread the van studs are using?

If you get onto this mob they will answer all your questions and supply you with nuts or studs if you require them.

Speedy wheels

if you are getting those alloys then you have to change the nuts anyway.
In that case I'd change the studs as well, otherwise why bother?

Hubs can be expensive so I'd just do the studs (which are cheap) assuming you are mechanical and have the tools.

OK - all this is good info.
I know that the current van stud and the Prado are different because I cant put the nut from one on the other - the van stud is slightly larger in diameter. The Prado alloys nuts are the washer type ones.
So - next question - possibly can be answered by the wheel shop people. If I go ahead and get these Prado alloy wheels, will I be able to find a set of nuts to put them onto the van studs - whatever type of thread it has?

cheers

Thanks for all the info people. I've got some homework to do.
cheers

Suitcase - the sites listed below are full of trailer component information ..

Martins Trailer Parts - catalogue

Spinny Things

Toyota Landcruiser and Prado wheel, tyre, and general engineering specifications ..

Wheel-size.com - Toyota

I'm inclined to go with the suggestion that the easiest and cheapest changeover is to buy complete new hubs with the Prado wheel studs.

Cheers, Ron.

Just an off topic note. I had a mate who used to get drunk and we would regularly have to carry him home and put him to bed. We called him suitcase as we reckon he should have had a handle implanted on his back so he was easier to carry.

Has anyone these nuts?

1/2 unf wheel nuts to suit Prado mags
232536160525 See this item on eBay
$30 a set of 5

https://m.ebay.com.au/itm/1-2-UNF-Chrome-Forged-Wheel-Nuts-to-suit-Toyota-Alloy-Wheels-/232536160525