What size tyres can I upgrade to with my BT-50

Patriot

Administrator
Hello,

My 2013 BT-50 has 265/65R17 tyres and I am wondering want size I can go to and what do people recommend. Am I right in thinking that it is a 30.5" tyre. Can it handle 33s and is that a good choice. I will get a 2" lift, but don't want to go too crazy!

Thanks

James
 

mac_man_luke

Well-Known Member
265/70R17 is a decent step up and is legal in a lot of states - a common upgrade for rangers/bts.
Best option if towing 1.5T or more often.

285/70R17 aka 33" is the best option for capability and fits no problems @ stock height and stock rims although 2" looks better. Not 100% legal in most states but is in some.
Power and economy are not affected too much but you can really feel it if you tow anything heavy.

Iv got 33s on mine and i wouldn't go back.
Actually considering a set of 35s for play tyres but they require a fair bit more modding to fit them.

1614414_674893812569588_542328947_o.jpg
 
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T M Goldie

New Member
I'm in the position of getting new tyres soon and I have 15 inch rims by 8, only have 31's at the mo and reckon that 33's would be a good option if they will fit on those rims, will get a 2inch lift too when I can afford it. Not sure of the legalities in Queensland though?
 

Croozer

Well-Known Member
I think a really good base would be for you mate is 2 inch lift and 33inch pro-comp all terrains. No bigger lift or tyres than that as other mods will have to be done.
That will get you anywhere you need and want to go and give good clearance all round.

Also if you are going to put front bar, side rails and rear bar, your lift you put in will have to deal with the extra weight.

People get a rig put a lift in and tyres on and realise later when they put bar work on there lift drops as they didn't allow for the extra weight.
 

SMOKEYR50

New Member
265/70R17 is a decent step up and is legal in a lot of states - a common upgrade for rangers/bts.

Best option if towing 1.5T or more often.



285/70R17 aka 33" is the best option for capability and fits no problems @ stock height and stock rims although 2" looks better. Not 100% legal in most states but is in some.

Power and economy are not affected too much but you can really feel it if you tow anything heavy.



Iv got 33s on mine and i wouldn't go back.

Actually considering a set of 35s for play tyres but they require a fair bit more modding to fit them.



1614414_674893812569588_542328947_o.jpg




Great looking rig.
 

Patriot

Administrator
You know this legal thing keeps cropping up. We should get all the information together in a sticky.
 

Croozer

Well-Known Member
You know this legal thing keeps cropping up. We should get all the information together in a sticky.


This could be a great idea James!
The only thing that really scares me is no one will want to go interstate after its all said and done :eek:

All the rules are crazy from state to state!

A classic example is my lift in Vic! All right my tyres are a little bit extreme and not really legal for road use but my lift is illegal and as far as I'm concerned it shouldn't be!
When I did my 3inch suspension lift I asked around everywhere I could about Vic laws. I was told a rule of thumb was 2 inch suspension and 2 inch body lift witch is 4 inch in total!
I don't like body lifts as they put to much strain on components body mounts and changes centre of gravity witch makes you top heavy and more susceptible to roll over.
In conclusion I only really have a 3inch lift that's safer than a 4 inch body and suspension, its still not legal! :rolleyes:
I also feel it has a lot to do how you drive around built up areas and small country towns. I have not been even looked at yet! Touch wood. :D But if I was a bit of a led foot and didn't respect the local laws I would of been pinged and put off the road long ago. Its a very fine line!

Might be a idea to try and grab the laws for this from each state and post it up as you said in a sticky!
 

BarKer

Well-Known Member
They are laws, every state has got its own regulatory body which supplies authorative advice, if it was up to me I would just point members their way.. You know it is a can of worms you will be opening up..
 

phs

Well-Known Member
Apparently in Victoria james your bt50 with 285 75 16 ( 32.8" ) is 5.08mm over the maximum allowable 50mm

that's if you can confirm your door jam reads 265 65 17
 

p76rangie

Active Member
Apparently in Victoria james your bt50 with 285 75 16 ( 32.8" ) is 5.08mm over the maximum allowable 50mm
This is where people have to be careful about reading standards. ALWAYS read the definitions in the standards.
Your tyre placard does not state a tyre diameter, it only states a tyre size. As already highlighted in another thread, the actual tyre diameter for a given size can vary from manufacturer to manufacturer and for different tread patterns from the same manufacturer.

The actual diameter of a tyre for a given size within the ADRs is specified as a range of diameters. The range relates to the sectional diameter of the tyre. In the above example of a 285/75/16, the calculated section diameter is the overall calculated tyre size (32.8inches) less the size of the rim of 16 inches or 16.8 inches. The standard allows a tyre size to vary from this calculated diameter by 4% variances less than the calculated diameter to 8% above. So it can be 4% of 16.8 inches smaller or 8% of 16.8 larger.

So when a manufacturer specifies a 285/75/16 tyre, he is stating that it must be a tyre between 32.1 inches (32.8-.07) to 34.1 inches (32.8+1.3). So by the standard, you can go 50mm larger than 34.1 inches.

This is by the latter ADRs. The older ADRs actually state no maximum diameter for a specific size, only a minimum, so theoretically you can go as large as you like within the modification rules.
 

phs

Well-Known Member
This is where people have to be careful about reading standards. ALWAYS read the definitions in the standards.
Your tyre placard does not state a tyre diameter, it only states a tyre size. As already highlighted in another thread, the actual tyre diameter for a given size can vary from manufacturer to manufacturer and for different tread patterns from the same manufacturer.

The actual diameter of a tyre for a given size within the ADRs is specified as a range of diameters. The range relates to the sectional diameter of the tyre. In the above example of a 285/75/16, the calculated section diameter is the overall calculated tyre size (32.8inches) less the size of the rim of 16 inches or 16.8 inches. The standard allows a tyre size to vary from this calculated diameter by 4% variances less than the calculated diameter to 8% above. So it can be 4% of 16.8 inches smaller or 8% of 16.8 larger.

So when a manufacturer specifies a 285/75/16 tyre, he is stating that it must be a tyre between 32.1 inches (32.8-.07) to 34.1 inches (32.8+1.3). So by the standard, you can go 50mm larger than 34.1 inches.

This is by the latter ADRs. The older ADRs actually state no maximum diameter for a specific size, only a minimum, so theoretically you can go as large as you like within the modification rules.


So your saying with type placard of 285/75r16. You can legally run a 36" tyre in Victoria ?

I have read and discussed the Victorian rules reguards tyre sizes to death with a lot of people.

This is definitely a new approach.

The best we have come up with is the best tyre placard size for that model, ie, not badge

Ie. 70 series landcruiser workmate runs a much bigger OD tyre than the GX or GXL
So it's debatable weather you could use that as it's the interpretation on the wording which as far as I'm concerned fairly open with " model " as the key word to interpret

model") is a particular brand of vehicle sold under a marque by a manufacturer, usually within a range of models, usually of different sizes or capabilities. From an engineering point of view, a particular car model is usually defined and/or constrained by the use of a particular car chassis/bodywork

I would be happy to debate me using the workmate tyre size as my Std on my GX

Can't say I have ever heard of your theroy wish it were true but I'm not getting any of it from the law and how it is worded .
 

p76rangie

Active Member
Can't say I have ever heard of your theroy wish it were true but I'm not getting any of it from the law and how it is worded .
Just to show I can admit when I get it wrong. It is only 4% bigger for radial road tyres and 3% smaller. But for tyres like snow tyres you can go bigger by a further 1%. So that would make it 5% larger. It is only where the manufacturer has listed a "Diagonal and Bias belted' tyres that you can go 8% bigger on.

These are the actual rules within the standard:

6.1.5. Tyre outer-diameter specifications
The outer-diameter of a tyre must not be outside the values Dmin and Dmax obtained from the following formulae:
Dmin = d + (2H . a)
Dmax = d + (2H . b)

where:
6.1.5.1. for sizes listed in Annex 5, and for tyres identified by the "tyre to rim fitment configuration" (see para. 3.1.10.) symbol "A", the nominal section height H is equal to:
H = 0.5 (D-d), for references see paragraph 6.1.2.
6.1.5.2. for other sizes, not listed in Annex 5, "H" and "d" are as defined in paragraph 6.1.2.1,
6.1.5.3. Coefficients "a" and "b" are respectively:
6.1.5.3.1. Coefficient "a" = 0.97
6.1.5.3.2. Coefficient "b" Radial, Run flat tyre for ordinary (road type) tyres 1.04, Diagonal and Bias Belted 1.08
6.1.5.4. for snow tyres the overall diameter (Dmax) established in conformity with the above may be exceeded by 1 per cent.


It should also be noted that these rules do not apply to a 4WD which has light truck tyres specified:
3.4 This vehicle standard does not apply to the tyres fitted to the following categories:
3.4.1 MB, MC, MD or NA when fitted with light truck tyres,


Other definitions you need:
6.1.2. Outer diameter of a tyre
6.1.2.1. The outer diameter of a tyre shall be calculated by the following formula:
D = d + 2H


where:
D is the outer diameter expressed in mm
d is the conventional number defined in paragraph 2.17.1.3. above, expressed in mm, 5/
H is the nominal section height in mm, equal to:
H = 0.01S1.Ra,
S1 is the nominal section width in mm, and
Ra is the nominal aspect ratio,
all as shown on the side wall of the tyre in the tyre-size designation in conformity with the requirements of paragraph 3.4. above.
 
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ian.c

Well-Known Member
I'm in the position of getting new tyres soon and I have 15 inch rims by 8, only have 31's at the mo and reckon that 33's would be a good option if they will fit on those rims, will get a 2inch lift too when I can afford it. Not sure of the legalities in Queensland though?
33s are fine on 15×8 rims I've been running 33×12.5×15s on the landcruiser for years on those rims with no problems, cant go too high with air pressure being 15s but the tyres do belly out nicely for driving very soft sand, higher profile also takes a bit more sting out of bumps especially with leaf springs.
EDIT Just noticed the date on the post I was replying to, anyway 33s are fine on 15×8s
 
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