help. Widening offset of wheels?

[jimb]

The boosts wheels (Puma) are +33 correct?

I will be either going the standard 235/85/16 or 265/75/16 tyres- which have almost identical circumference but 265 slightly wider.

What issues does the reducing offset create?
Options are either +25 or +15

[n plus one]

The boosts wheels (Puma) are +33 correct?

I will be either going the standard 235/85/16 or 265/75/16 tyres- which have almost identical circumference but 265 slightly wider.

What issues does the reducing offset create?
Options are either +25 or +15

Nothing, except for legal issues and (possibly) wheel bearings (if you go too wide).

I'd go ET15 - it'll give you more lock (if you tweak the stops) and a more aggressive stance.

[jimb]

Thanks.

So the wider exposes the bearings more?

How does it affect the bearings ( please talk to me like a 10 y o. )?

The 15 is further towards than the 25- so would I better off being more conservative at 25?

To check legality in qld I think it's basically tyre can protrude past flares.


So if I move from 235 to 265 = 30mm outward then if I went to 15 offset, then another 18mm outward- so total movement outwards is 48 mm.

Am I correct in my thinking? So just plum bob the flare with standard wheel to see how much is available I suppose.

[R Miller]

it doesn't expose the bearing more, just changes the load point, therefore acting as a basic lever the bearings will see more load and potentially could wear out faster,

I don't think your gonna have to much concern if your only moving the offset by 15 or so mm though

[303gunner]

To check legality in qld I think it's basically tyre can protrude past flares.

So if I move from 235 to 265 = 30mm outward then if I went to 15 offset, then another 18mm outward- so total movement outwards is 48 mm.

Am I correct in my thinking? So just plum bob the flare with standard wheel to see how much is available I suppose.
If you go to a 30mm wider tyre, the centreline of the tyre stays in the same place and the extra width is 15mm towards the chassis and 15mm towards the flare. A +15 offset rim will move the chassis side of the tyre 18mm away from the chassis (so you have an extra 3mm clearance on full lock and articulation, in theory!), while the flare side of the tyre will move out 33mm wider than stock (15mm tyre +18mm change in offset).

Under the Qld regulations, you are permitted to widen the track of a 4wd by up to 50mm (see section 4.2.11 in the NCOP below). Going to +15 offset rims will increase your track by 36mm, so is within the allowable limit. "Track" is the measurement from centreline of tyre to tyre, not outside overall width.

Light vehicle modifications (Department of Transport and Main Roads) (http://tmr.qld.gov.au/Safety/Vehicle-standards-and-modifications/Vehicle-modifications/Light-vehicle-modifications.aspx)

[jimb]

If you go to a 30mm wider tyre, the centreline of the tyre stays in the same place and the extra width is 15mm towards the chassis and 15mm towards the flare. A +15 offset rim will move the chassis side of the tyre 18mm away from the chassis (so you have an extra 3mm clearance on full lock and articulation, in theory!), while the flare side of the tyre will move out 33mm wider than stock (15mm tyre +18mm change in offset).


Thanks. Silly error. So If I am being a stickler then I would have thought
265 with 15 offset will be illegal by a few mm. (outside of tyre goes out by 33mm [18mm offset+15mm tyre]

I measured the top of the flare to the widest part of the tyre and got 29-30mm. I could probably be more accurate- but has anyone had experience with this offset and tyre size?

The other option is the offset @ 25mm, which would be fine. so outside of tyre goes out by 23mm [8 mm offset + 15 tyre]

The Flare is wider at the top than where it meets the vehicle. I assume you can take the measurement from the top of the flare?

[n plus one]

Thanks. Silly error. So If I am being a stickler then I would have thought
265 with 15 offset will be illegal by a few mm. (outside of tyre goes out by 33mm [18mm offset+15mm tyre]

I measured the top of the flare to the widest part of the tyre and got 29-30mm. I could probably be more accurate- but has anyone had experience with this offset and tyre size?

The other option is the offset @ 25mm, which would be fine. so outside of tyre goes out by 23mm [8 mm offset + 15 tyre]

The Flare is wider at the top than where it meets the vehicle. I assume you can take the measurement from the top of the flare?

No, track is a measurement between the centre of the wheels NOT the outside, Tyre width does not affect track.

If you are ok to go 50mm wider in QLD then you can go to ET8 offset wheels - assuming standard wheels are ET33. You should also note that the factory optioned heavy duty steel wheels for your vehicle were ET20.6 meaning that (with rounding) you're probably ok to go to ET-4.

Try going this way round - figure out your desired tyre size, your rim size (width)follows from this, then calc your ET based on not letting the inside edge of the tyre be any closer in to the truck than the standard size tyre on the standard width and offset rim, then figure out if your track is now too wide for the rules.

Alternatively, just go 265/75s on 7inch rims with ET15 and you'll be fine :D

For context, I ran 265/75 on the standard rim and the just scrubbed on the front radius arms and rear spring towers. I now run 7 inch ET10 wheels with 255/85 and have no issues (and 265/75 would be fine too).

[jimb]

aren't there 2 legal issues?

1. Not allowed to widen your track by more than 50mm
2. Not allowed to have tyres extending past the outside of the vehicle (flare)

I hear what your saying about track v tyre.

Dont suppose you have a photo of your rig with the 7 inch ET10 wheels with 255/85?

[jimb]

Like 303gunner said. The track width change will be legal, all I am concerned about is the tyre popping past the flare and having to extend the flares.

when you say I'll be fine with 265/75/16 with offset wheel +15- do you mean it will not protrude past the flare- because that is what I am curious about.

[n plus one]

Like 303gunner said. The track width change will be legal, all I am concerned about is the tyre popping past the flare and having to extend the flares.

when you say I'll be fine with 265/75/16 with offset wheel +15- do you mean it will not protrude past the flare- because that is what I am curious about.

There are actually a whole bunch of legal issues - including track, rolling diameter, rim width, flare coverage, load rating of wheels and so on.

Regardless, 265/75 on ET15 will be easily under the flares on a 110 - you can pretty much squeeze a 285/75 on a ET0 under the flares.

[chook73]

Sorry but isnt the track measured to the centre of the rim? Therefore a wider tyre on the same width rim as stock which changes the offset up to 50mm is perfectly legal as long as the total width, diameter or rolling radius change doesnt exceed the legal requirements....

The way I read it (VSI #9) in NSW you are allowed up to 25mm track increase or up to 26mm wider than the largest wheel recommended by the manufacturer and for the total wheel and tyre change, no more than 15mm over the largest diameter.

FYI I ran 265/75mm on a 0 offset king rim for ages and had no problems at all....

[n plus one]

Sorry but isnt the track measured to the centre of the rim? Therefore a wider tyre on the same width rim as stock which changes the offset up to 50mm is perfectly legal as long as the total width, diameter or rolling radius change doesnt exceed the legal requirements....

The way I read it (VSI #9) in NSW you are allowed up to 25mm track increase or up to 26mm wider than the largest wheel recommended by the manufacturer and for the total wheel and tyre change, no more than 15mm over the largest diameter.

FYI I ran 265/75mm on a 0 offset king rim for ages and had no problems at all....

Yep, sounds right to me.