Another wheels thread...sorry!

Hoping someone might be able to help. I currently have 19.5 steel rims with 265/70R19.5 tyres and the rims appear to be zero offset.

There are air bag on the rear springs and the tyre appear to just be rubbing. I am looking to change to alloy rims, but even 16x8 would need a 1 or 1.5" negative offset. I would have preferred to go to a 17x9 but that would require an even greater negative offset.

Does anyone have the same set up with alloys? I have searched Summit and Mr Wheels Deals and the eagle and Ultra rims seem to be only available in zero or -.5" offset.

Hi Nugget, i'm not sure you're measuring it correctly, or in the way they specify the rims anyway. (This is from memory from a couple of years ago, so please someone correct the detail). Usually it's measured as 'back-spacing' which is measured from the inner face of the rim to the inner face of the wheel centre. It seems you may be measuring from the middle/centre-line of the rim? If your airbags are rubbing you probably don't have enough back-spacing and therefore those wheels probably shouldn't be used as a reference (unless your airbags are larger than normal). Can someone fill us in on standard OKA back-spacing? Again from memory (without having measured again) the back-spacing was about 4"-4.5" and it was a fairly standard measurement for other vehicles and therefore quite easy to get rims...
Cheers, alister

Hi Alister, I am pretty sure it is the same thing just a different language. Some talk backspace and some talk offset...must admit I am more used to offset but if I have it right, an 8" wide rim with a 4" backspace is the same as a zero offset. An 8" rim with a 4.5" back space would be a .5" (1/2") offset

Happy to be corrected as well. Cheers

yep, agreed. from memory most of the wheels i looked at specified back-spacing rather than offset. IMO back-spacing is more useful as if you change rim width the back-spacing stays the same but the offset changes otherwise you run the risk of the tyre fowling on springs etc. My experience was that there were heaps of wheels out there with the same back-spacing as the OKA... including the suppliers you mentioned above.

Hi Nugget and welcome to the wonderful world of 'Oka'ing'

Our standard Oka 19.5's which are identified by a little stylised palm tree over a circle symbol stamped into the face of the rim are 19.5" X 7.5" with a backspace measurement of 5" and a 'front space' measurement of 3 3/4". The steel centre is 5/16" thick so I'll let you do the maths on offset calculation

We've got Airbag man 6" airbags front and rear on #413 and the clearance between the 305/70 R19.5 tyres on Mullins rims (also with 5" backspace) and the airbags is about 40mm. IMO your issue is not a rim problem but an airbag problem, they need to be moved inboard. This may require a bit of realignment of the tailpipe and is also a good opportunity to ensure that the muffler is not baffled. Replacing a baffled muffler with a straight through muffler is probably the best bang for buck 'power upgrade' you can do to an Oka.

IMO your existing 265's are a truly woeful tyre both on road and off road and should be ditched at the earliest opportunity.

Deano

nugget wrote: Hoping someone might be able to help. I currently have 19.5 steel rims with 265/70R19.5 tyres and the rims appear to be zero offset.

There are air bag on the rear springs and the tyre appear to just be rubbing. I am looking to change to alloy rims, but even 16x8 would need a 1 or 1.5" negative offset. I would have preferred to go to a 17x9 but that would require an even greater negative offset.

Does anyone have the same set up with alloys? I have searched Summit and Mr Wheels Deals and the eagle and Ultra rims seem to be only available in zero or -.5" offset.

If I could get my head around which direct offset is in relation to backspace it would help,
I did find a few Raceline brand rims that were ~3600 pound rated 17" alloys... so potential fine for a lighter vehicle more so that a loaded 8ton job.

https://www.racelinewheels.com/p-1605-935bz-defender.aspx#!lang=0https://www.racelinewheels.com/p-1605-935bz-defender.aspx#!lang=0
935BZ-79080-00 0 offset/5" back space
935BZ-79080-12 -12mm offset/ .5" backspace

The question is whether they would work?


Back to the airbags... can they move inwards at all?
What model are they?

Thanks Deano,

Think I will go with the 17x9 rims with 4.5" back space and make it work with the air bag. Thanks for heads up on the muffler...it was on the list Totally agree with your assessment of the 265's...woeful is being kind. At first we thought the steering might be a bit cactus but then I noticed the tyres were tracking any line in the road surface. To make it worse I am pretty sure the front are retreads/regrooved...very strange looking tyre indeed.

Holmz wrote:

nugget wrote: Hoping someone might be able to help. I currently have 19.5 steel rims with 265/70R19.5 tyres and the rims appear to be zero offset.

There are air bag on the rear springs and the tyre appear to just be rubbing. I am looking to change to alloy rims, but even 16x8 would need a 1 or 1.5" negative offset. I would have preferred to go to a 17x9 but that would require an even greater negative offset.

Does anyone have the same set up with alloys? I have searched Summit and Mr Wheels Deals and the eagle and Ultra rims seem to be only available in zero or -.5" offset.

If I could get my head around which direct offset is in relation to backspace it would help,
I did find a few Raceline brand rims that were ~3600 pound rated 17" alloys... so potential fine for a lighter vehicle more so that a loaded 8ton job.

https://www.racelinewheels.com/p-1605-935bz-defender.aspx#!lang=0https://www.racelinewheels.com/p-1605-935bz-defender.aspx#!lang=0
935BZ-79080-00 0 offset/5" back space
935BZ-79080-12 -12mm offset/ .5" backspace

The question is whether they would work?


Back to the airbags... can they move inwards at all?
What model are they?

Holmz. 16 X 8's with a -5 offset will fit all standard Oka's with no problems. I've run them with 315/75 R16's and 325/85 R 16's with no fouling issues on our LT. 16 X 8 with 0 offset will easily fit on the rear of all standard Oka's but may foul on the front depending on what tyres you run.

Deano

Nugget, if you're planning on running a 'lightweight' Oka ditch the airbags as they're not necessary with properly tensioned springs, you'll have a better ride and less complex suspension with fewer potential 'points of failure'. We've rear airbags which I lazily had installed to avoid retensioning the rear springs, IMO it was a mistake and I'll be removing them. A better HD solution would be to install an additional 3rd leaf that extends under the shackle pin (unlike the factory 3rd leaf) and install the LT dual shocker upgrade.

Deano

Hi Deano,

Mate I am not a fan of airbags and I was already thinking of removing them if I can get the weight down. Already have dual shocks at the rear. I plan on getting the springs re set...the front passenger looks like it is down a bit but will leave that until nearer the end of the build when I see how it all pans out with weight. What tyres were you running with the 325/85R16's??

The tyres I was running were 325/85 R16 Michelin XML's. probably the best off road tyre available in the country at 39" but bloody heavy. Ian Jones here in Melb has them and also rated steel rims to suit which is where I got mine. They're available from Michelin at vast expense ie. $1500 or so but a lot cheaper from Ian.

You may have seen them before on one of these vehicles



They look very good on the Oka, aggressive as hell they really look the part but not the best choice for highway work.

Deano

I don't see an airbag as a point of failure as if they go, so what... Drive home and install another one! i do like being able to tilt my oka for camping though, which is one of the main benefits in my view. Anyway, back to wheels...

Just Fitted
17" Rims and 37" Patriot Tyres from Truck Super Singles in Queensland
Excellent quality





David

Dean and Kaye Howells wrote: ...

Holmz. 16 X 8's with a -5 offset will fit all standard Oka's with no problems. I've run them with 315/75 R16's and 325/85 R 16's with no fouling issues on our LT. 16 X 8 with 0 offset will easily fit on the rear of all standard Oka's but may foul on the front depending on what tyres you run.

Deano

Roight, but the 17" tyre will not fit the 16" rim.
The 19.5" combo that Dean had were a 4.25" backspace (maybe 8 or 9"width???). They looked good for a truck tyre.

So I have the 265LT I think? They are 16LT, and seem a bit narrow and a bit short, but the weight is still not super light.
So I keep chin scratching on 17" and hence the link to the Raceline brand, and few if any seem like they are forged rims. But there ae more 17" tyre choices.

Dean and Kaye Howells wrote: Nugget, if you're planning on running a 'lightweight' Oka ditch the airbags as they're not necessary with properly tensioned springs, you'll have a better ride and less complex suspension with fewer potential 'points of failure'. We've rear airbags which I lazily had installed to avoid retensioning the rear springs, IMO it was a mistake and I'll be removing them. A better HD solution would be to install an additional 3rd leaf that extends under the shackle pin (unlike the factory 3rd leaf) and install the LT dual shocker upgrade.

Deano

I was thinking of getting the boilermaker to make new leaf saddles with the airbag mounts slightly in-board so that they could be added if I wanted more height... Say for some reason like getting the damper in the middle of the travel or extra gear in the tray.
... and then maybe running 5psi in it if it was 'effectively' not being used.
And I actually ordered a single one to give to the boilermaker to use for dimensions. (they were ~6.72" in diameter from memory.)

Then part #2 of that whole thought train... is what to do for shocks. There are dual Monroes, dual Billies/Koni with lighter dampening, or something else.
There are also the air shocks with ~1"or 1-1/2" shafts that nitrogenéd up to a few hundred PSI that could be used to tune the ride height... Assuming air or nitrogen is available the height gets changed only just occasionally.

As it is "a system", the damping and all the unsprung weight play together... And the fancier bypass arrangements also have a ride height factor as they are position sensitive rather than velocity sensitive.
So it is a conceptual mongrel of variables along with tyre/rim sizes to arrive at anything more than just more stroking of the beard and questions.

I still think that a 37" may be bigger than I want on a lightly loaded Phaser powered DC-Ute, and a heavy duty 12x35" seems like it could be m,ore optimal?
(...^Questions^)

17 x 9 & 16 x 8 mine spec 1800kg factory rims here in W A OKA 8 stud NT special order

8 stud $300 each

ph 0429 831040

outyonda wrote:

17 x 9 & 16 x 8 mine spec 1800kg factory rims here in W A OKA 8 stud NT special order

8 stud $300 each

ph 0429 831040

^Cool^...

What do they weigh?

Now I have to wear out the 16LT and figure out if it is 16" or 17" has better tyre sizes for me.

Hi David, mate you are talking my language now I looked at their rims but have decided to go alloys for the weight both as part of the vehicle weight and me changing a tyre after 2 shoulder recons.

How do you find the Patriots..they were my choice but I was worried they might be a bit noisy although having run MickeyT MTZ's on Defenders for 10 years I probably wouldn't notice

I recently changed from 16" to 305x70 19.5" and the air bag just rubbed sometimes. I undid the the nut at the top of the air bag where the bolt runs through the mount plate, let the air bag down then elongated the hole towards the chassis to get the bag away from the tyre. This was an emergency quick fix that has done over 10,000 km and no sign that it has rubbed on the tyre after Oka type off roading. My airbags are not the flash bellows type but the cylindrical (go cart tyre) type.