Trailer tyre size

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gadgets

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Anyone know if the same rules apply for putting bigger tyres on a trailer as it does with cars, only a certain size increase allowed etc. Cant seem to find info anywhere on it.
 
I don't think so. I have a mate that runs 33" MTZs on his camp trailer. Looks awesome too! Bigger tyres are usually illegal because of the braking performance.
 
Given that not all trailers have to be registered I'd suggest it's a state by state thing. Our box trailer is home made so it's bigger than a standard box trailer but it also has bigger tyres than the rims came with and Vic Roads aren't interested, I'm not even sure there is a place on the rego for wheel/tyre size.
 
I imagine that if they dont stick out past the guard & are not bald then the authorities dont care much.
 
Given that not all trailers have to be registered I'd suggest it's a state by state thing. Our box trailer is home made so it's bigger than a standard box trailer but it also has bigger tyres than the rims came with and Vic Roads aren't interested, I'm not even sure there is a place on the rego for wheel/tyre size.

On the drawbar of the trailer it has a plate similar to a vin plate of a car, it states the year of manufacture ,tare weight, tyre and rim size. Im in WA.
 
I don't think so. I have a mate that runs 33" MTZs on his camp trailer. Looks awesome too! Bigger tyres are usually illegal because of the braking performance.

Bigger wheels/tyres can put pressure on axles, hub bearings etc too though ? Might be wrong?
 
Oh yeah you might have different rules there, you guys have to put the weights on commercial vehicles or vehicles over a certain weight or something. Over here only trailers of a certain size need compliance plates, our old cattle trailer needed it but our home made box trailer doesn't.
 
Krafty I suspect Vic will end up like the rest of the states with trailer rules that cover everything.

No problem until KLUNK and plod or the insurance company decides that your trailer wasn't legal.

Not registered? In NSW now, the small stuff still has to be registered, but it now longer has to be inspected each year. All they were really checking was that your lights worked and you had tyres with legal tread. they really didn't give a stuff about anything else, especially the draw bars now bowing after I stuffed up welding on angle to patch massive rust on them.

There are rules on how you must design your home built (usually in a downloadable pdf) and the regs in many states even have require stuff like the safety chain(s) meet a specific Australian Standard, including being marked as such and there is another A.S. for the shackles.
This came up recently on a camper trailer list.

AFAIK, in NSW, the manufacturer has to affix a plate specifying load, tyres, etc and you need to stick to that. Otherwise, you would have to show that the changes you made meet the built your own trailer regulations.

It is just my 2c, that there should not be any problem of changing the tyres, but you would need to ensure that it still met design requirements. The major problem would be ensuring mud guard clearances for larger tyres..

Different wheels shouldn't affect braking. Normally, you would just need to adjust the link/hitch higher to ensure the trailer was level. Stuff like type of brake (non, over ride, safety) is covered under the regulations and AFAIK varies by gross mass of the trailer.
 
Speaking of larger tyres, I wanted to put matching str mags on my trailer but they sit to close the chassis, question are those spacers legal on a trailer, I know there not legal on a vehicle, but is a trailer different
 
Considering we once asked Beaurepairs to change out the hubs on our box trailer to match the Commodore we had at the time and they fixed it by providing us with 8 washers per wheel nut so the wheels fitted the existing hubs I'm thinking rules on standard box trailers (in Vic) aren't really that strict. Also take into consideration that some smaller trailers only require registration plates so speed cameras can see them (i.e. they can have drawn plates that match the car).
 
AFAIK, in NSW, the manufacturer has to affix a plate specifying load, tyres, etc and you need to stick to that. Otherwise, you would have to show that the changes you made meet the built your own trailer regulations.

Bugga - just looked at the trailer and it's mud-covered compliance plate which states 165r14. Oh well, I'll just have to behave myself so no-one sees the LT195r14C I just put on it.
 
For NSW, this is the sort of question that you can ask on the RTA/RMS web site or telephone enquiry line. Alternatively wander past your local RTA site that does vehicle rego inspections and ask one of the guys.
 
The definitive document to reference is VSB1 available from the DOTARS website. This is the National Code of Practice for building small trailers.

Section 20 Wheels and tyres
All wheels and tyres must comply with ADRs 23 or 42 as relevant to the type of tyre used. Wheels and and tyres must be adequate for the loads they are to carry and the speeds at which they are to be towed. THe GTM of the trailer must not exceed the sum of the load ratings of its tyres.

As long as they have the load rating, fit within the guards and legal tread they are fine.

Having imported a few trailers from the US you get an understanding of the requirements for registration.

Just remember that bigger and heavier tyres will change how the trailer handles and watch you hitch height.

The area that you will get pinged for is if the trailer is over 2.5metres wide. A number of boat trailers have been brought in from the US and the importers (generally private) have got them registered. The authorities have started to take notice of this and people are getting booked for being overwide.
 

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