Tyres again... 255/85R16 on a defender 90?

[Toxic_Avenger]

I'm after info regarding tyre sizing for my 2012 90.Would love to hear from those who have 'been there / done that'. I'm looking ton fit a 255/85/R16 (33") tyre to the 90.

Details regarding my vehicle below:

Stock height (no lift), original suspension with 35,000km on the ODO.
Bullbar, winch and rear bar- contributes to extra weight, suspension sag
Dual finish alloys- 16"x7" IIRC (unsure of offset, but +35 rings a bell?)
I want a larger diameter M/T tyre to replace an aging and very chipped set of 235/85R16 Goodyear wrangler MT's that have been on the vehicle since new


The factory 235/85R16 work well, but I'm often left scrubbing the diff in a few of the ruts and tracks I drive, moreso at lower tyre pressures.
I'm not in a position to lift the vehicle yet, but am looking for something that is a little bigger.
Not sure whether to lean towards a skinny tyre or a fat tyre... my thoughts are lean towards the narrow. Not sure about the trade off of tyre diameter vs tread width in relation to accelleration / handling, but keen to know more.

From what I read in countless hours of searching is that the 90's have a different (smaller) rear spring diameter and top bracket, making more room for wider tyres (at the same rim offset) than the 110's or 130's. I've heard whisperings of some potential loss of steering lock at a 33" tyre size, but not sure if the limiting factor is tyre height or tyre width...


Keen on the BFG Mud Terrain T/A KM2's in 255/85/R16. ie a 33"x 10" on a dual finish alloy rim.
Has this combo been done before? Any feedback?

[cuppabillytea]

I'm keeping an eye on this Mitch. I'll be up for new ones soon myself. So far I''m leaning toward standard Conti ATs. They've served well so far. However I can see why you'd be looking for a bit more clearance.
The size you're thinking of is going to make it vague in the tar though.

[Vern]

Not to be rude, but there is so much info on that Tyre size on here! Have you tried using the search function?

[Toxic_Avenger]

I like the idea of a mud tyre, they might be a bit more noisy and not as good on road as an AT/HT, but on the other hand, my wrangler's have never let me down when I've needed them. Except for that time I'd sunk to the diffs in slimey mud- hence the hope for larger diameter rubber!

Can anyone explain what the biggest contributing factor is with handling changes with a tyre? Does larger width cause it to be vague, or is it the diameter, or just the sheer extra rubber and weight have to be spun by the engine that makes the vehicle sluggish?
One thing I've read is that 255/85/R16 will bring the speedo up to pretty much accurate

On width... wouldn't larger contact patch would be better for low traction conditions off road, but likewise the narrower tyre puts more concentrated pressure on the ground like for mud snow etc?

[Toxic_Avenger]

Yes I've searched, and a clear answer for my example was not found. I actually forgot to add my bibliography to my first post- sorry

The good oil has lots of broken links, and info that is not specific to the 90. Most posts are from 2005! Most posts don't even discern between the model on which said tyres fit.

My line of questioning is particularly focused at a stock suspension puma 90 which is carrying a bit of extra weight. This vehicle has the dual finish alloy wheels (different offset to the steelies), and I particularly want a larger diameter wheel for predominantly offroad use- a MT tyre.

I'd consult the opinions of a professional, but out of the 2 places I called yesterday, one of them said 'there's no such thing as a 255/85R16' :eek:. It's a larger investment that will be with me for many years, so want to get it right.

[cuppabillytea]

Hi Mitch. The reason I think it would be a little more vague is the little extra hight you would be putting on your side walls. I imagine that the shorter wheel base of the 90 would make it quicker steering which in turn would accentuate any vagueness.
I was toying with the idea of going wider but not necessarily higher. Thanks for being my Guinea Pig. :p

[D90 orkney]

After doing similar research I was under the assumption that you can go 265/75/16 with no rubbing and no lift.

I have 285/75/16 with 30mm spacers on sawtooth rims and 2 inch lift. I plan to take spacers off and go -25 with steel rims soon. I feel the extra width is great off road keeping rock walls and the such away from my panels. Also my turning circle improved with the offset

[D90 orkney]

Give Andrew at LRA a call. They are normally very helpful and know there stuff

[Toxic_Avenger]

After doing similar research I was under the assumption that you can go 265/75/16 with no rubbing and no lift.

I have 285/75/16 with 30mm spacers on sawtooth rims and 2 inch lift. I plan to take spacers off and go -25 with steel rims soon. I feel the extra width is great off road keeping rock walls and the such away from my panels. Also my turning circle improved with the offset

Stands to reason- the stock rubber is 235/85/R16 - 31.7".
265/75/R16 is a 31.6" (but 30mm wider than stock- 15mm wider each side of the rim bead).
So you are saying that an additional width increase of 30mm is about the limit on a 90 before you start running into clearance issues on the sawtooth alloys?

I'm not really keen on spacers. I'd more likely than not run stock sized rubber before going the spacer route.

Does anyone have any feedback of tyre clearance within the wheel well running 33's? Is the general idea (on a 90) that tyre width is a limiting factor or tyre height?

[D90 orkney]

Stands to reason- the stock rubber is 235/85/R16 - 31.7".
265/75/R16 is a 31.6" (but 30mm wider than stock- 15mm wider each side of the rim bead).
So you are saying that an additional width increase of 30mm is about the limit on a 90 before you start running into clearance issues on the sawtooth alloys?

I'm not really keen on spacers. I'd more likely than not run stock sized rubber before going the spacer route.

Does anyone have any feedback of tyre clearance within the wheel well running 33's? Is the general idea (on a 90) that tyre width is a limiting factor or tyre height?

From my understanding, I wanted 285 so to not hit bump stops and clear everything I read that 30mm spacers were needed or -25 offset rims. I'm not keen on the spacers either but it was a means to an end at the time.

I also understand that 265 was the most you could run on a 90 stock. I don't think 75 or 85 will make much of a difference

[noyakfat]

I would love to help, Mitch, but I have a 110 not a 90, so have no knowledge or experience of the 90 tolerances.

However, I have been running 265/75R16 since new, on King steel wheels 16x7 with zero offset. I find the vehicle runs straight and true, not "vague" in any way. I keep a regular check on pressures, do a rotation and balance every 5,000 km and a wheel alignment every 10,000 km.

My Hankook Dynapro M/T's have lots of tread left after 37,000 km and I've been very happy with them. My 110 is my daily driver to and from work and gets off road regularly onto the stoney roads of the Brindabellas.

I am also interested in the 255/85R16 as a possible replacement when the Hankooks eventually die.

Sorry I couldn't help with any real relevance to your enquiry, but I'm also watching with interest.

Cheers,
Nige

[Black 110]

I'm after info regarding tyre sizing for my 2012 90.Would love to hear from those who have 'been there / done that'. I'm looking ton fit a 255/85/R16 (33") tyre to the 90.

Details regarding my vehicle below:

Stock height (no lift), original suspension with 35,000km on the ODO.
Bullbar, winch and rear bar- contributes to extra weight, suspension sag
Dual finish alloys- 16"x7" IIRC (unsure of offset, but +35 rings a bell?)
I want a larger diameter M/T tyre to replace an aging and very chipped set of 235/85R16 Goodyear wrangler MT's that have been on the vehicle since new


The factory 235/85R16 work well, but I'm often left scrubbing the diff in a few of the ruts and tracks I drive, moreso at lower tyre pressures.
I'm not in a position to lift the vehicle yet, but am looking for something that is a little bigger.
Not sure whether to lean towards a skinny tyre or a fat tyre... my thoughts are lean towards the narrow. Not sure about the trade off of tyre diameter vs tread width in relation to accelleration / handling, but keen to know more.

From what I read in countless hours of searching is that the 90's have a different (smaller) rear spring diameter and top bracket, making more room for wider tyres (at the same rim offset) than the 110's or 130's. I've heard whisperings of some potential loss of steering lock at a 33" tyre size, but not sure if the limiting factor is tyre height or tyre width...


Keen on the BFG Mud Terrain T/A KM2's in 255/85/R16. ie a 33"x 10" on a dual finish alloy rim.
Has this combo been done before? Any feedback?

Hey mate,

This has been done before, and the short answer is yes, you should not any clearance issues.
I was so very close to doing the exact combo on my 110. I stopped short however.
I spend a lot of time out bush. 255/85x16 is one of the hardest sizes to get consistently. No one carries this size out bush. If you are intending on a lot of remote travel, the most common sizes you will be able to get if you happen to have a tyre failure are: 265/75x16 and 285/75x16.
So I ended up going with a set of 16x8 Kings Steel Wheels in 0 offset with 285/75x16 BFG KM2s.
Am I happy with them?
I wouldn't change the combo for anything else. The steering response is improved, the wider wheel track from 0 offset wheels gives a mush more confident feedback and feel when on all surfaces.
One more thing to consider, go Land Rover HD front springs, that's the setup I have on my front end, and I love it.

In reference to your question regarding skinny vs fat tyres; it depends on where you are driving mostly. If you are doing more mud driving, skinny tyres are actually better, as they cut down onto the hard surface underneath. If you are doing more sand driving, fat is the way to go, bigger footprint when you drop air pressures, and allows the tyres to sit on top of the sand.
Overall, tyre size is relevant to where you drive most commonly.

Believe it or not, the 235/85x16 is a very good compromise, as is the 255/85x16. If I didn't go bush as often as I do, then I would have fitted the 255/85x16. If you do go this way, be aware that you will be very limited to brands, and it is quite common for there to be very limited stock in Australia from time to time.

Good luck with your choice, it's not an easy one!

Here's a recent pic...

[Toxic_Avenger]

I thought I'd go old-school and do some testing to see what the limitations of the 90 are when it comes to flex...

Took a drive out to a roadside quarry / gravel storage area ond drove the closest thing I could get to:

https://www.aulro.com/afvb/

https://www.aulro.com/afvb/

http://www.aulro.com/afvb/attachment.php?attachmentid=110819&stc=1&d=1467447523

I didn't take an accurate measurements, but eyeballing it gave the following measures (Dodgy science alert! Take measurements as a guide only):

So what you all see above is stock suspension, probably a little bit sagged / worn, but with factory sway bars and everything else intact.

What I observed:
The Diff tubes are about 35-50mm off the bump stops on the compressed corners.

On face value, what I can see at this level of compression is about 20mm space between the inner sidewalls and the coil spring brackets at this level of compression. This appears to be the limiting factor for tyre fitment on a 90. This means that going wider tyre treads will pose issues with the tyre fitment. This could be overcome with wheel spacers, or different offset rims.

From what I can see, the tire tread at the 12 o'clock position, has plenty of room before it impacts the inner guards at the amount of flex pictured (not yet on bump stops).

Clearance to the flares is off by heaps. You'd need to run some pretty wide rubber to start having issues in this area at my offset without spacers, but you'd run into issues in other areas before that...

What I expect would happen when on the bump stops:
If we suppose that the the bump stops were to compress that remaining 35-50mm and bottom out against the axle tubes, then this would bring the tread of the tyre say 2 inches closer to the innder guard- leaving approx 35mm or so to the top inner guards.

There appears to be plenty of room at the front and rear of the tyres (ie the 9 and 3 o'clock positions of the wheel).

I can't really guess what would happen in regards to the inner tyre sidewall and the coil spring bracket when on the bump stops... but I believe we'd be pushing it fine within anything much wider than a 255 width tyre using the dual finish alloys. As it stands there is approx 20mm to the coil spring bracket when running a 235 tyre. Bump this up to a 255 (and have an additional 20mm width- ie 10mm per side of the rim bead), and you will be marginally closer. This distance seems to be fairly consistent front and rear.
The biggest concern with this is that the wheels camber in (gain negative camber relative to the body) when under compression, so while the body of the vehicle is pushed away by the compressing coil to some extent, the clearances will, I believe, get closer as suspension compression increases.


If I find some time tomorrow, I might put it on the flat and jack it until I reach the bump stops. Might even remove the sway bars for giggles...

[MLD]

Mitch I can't comment on the D90 and 255/85 Spring hanger rubbing problem. Without knowing your offset of your rim the ideal for a 255/85 is a zero offset. Returns steering lock to the same as 235/85 if not better. Fits inside the flares and visually fills the flares and wider stance for better stability off road.

While it's correct to say a 255/85 is as rare as hens teeth in the city and worse in the country I've taken my spare tyre to more towns than I've hot dinners. They essentially go on holidays with me. The BFG km2 is a great tyre. I'm on my third set and yet to have a broken bead or flat tyre even with much abuse. Carry a second spare if you must and take it on a holiday when you go on long trips.

The MT82 gearbox is low enough geared to carry the extra ratio of the 255/85 and yes it corrects the ODO.

Do it, with the 255/85 you will appreciate the extra height and appreciate not having to turn the extra width of the 285/75. Wider tyres sap power, increase fuel burn.

MLD

[Tombie]

They fit fine mate. And they're not that rare.

[Tombie]

No rubbing at all on Spring hangers with a 90

[strangy]

Regarding tyre size availability "outbush"
Very little is available in any size let alone brand, off the shelf.
The concept of "outbush" is widely romanticised and if you genuinely find yourself "outbush" (having prepared well) in need of a tyre of any description, you will be lucky to have a choice of 2nd hand, barely usable, or retread.
Popular/typical sizes are whatever happens to be in demand.
When heading into town for business, many roadhouses on the favourite tracks buy a few 2nd hand 75% ish worn tyres to sell to hapless travellers.
If you can find a brand "x" tyre to match your brand, or importantly size "y" tyre to match your size, outside of a town without a retailer, you are simply lucky.
Even the major suppliers in Alice cant be counted on to supply on the spot.

Just get the size you want and carry a second spare if genuinely heading remote.
Whatever tyre size you are running, it is an inconvenience if you need one in the middle of nowhere.

[Toxic_Avenger]

Sage advice Strangy.
This is pretty much the story of my life living in Tamworth. Half the reason things take me so long is that the things I want are not in the town I am in.

[Tombie]

Sage advice Strangy.

This is pretty much the story of my life living in Tamworth. Half the reason things take me so long is that the things I want are not in the town I am in.



You will insist on living in "Land Cruiser country" [emoji48][emoji6]

[Sirocco]

I reckon they would rub off-road with stock springs.

I have been running 255/85 on wolf rims for the last 8 years but always had a 2" lift with no issues what so ever.

The issue of availability is a moot point, we're in Australia, as Strangy said, it's just an inconvenience. The main thing putting people off is options. BFG MT KM2, Maxxis Bighorn MT and that is it. Cooper use to do the ST Maxx but stopped making them. Even though many LR and G wagon guys run this size, they are not popular.

In terms of stability I doubt you would notice any difference. A wider tyre isn't more effective in sand as when you air down the footprint elongates, not widens. 255-285 is only 3cm. Not worth worrying about, not a deciding factor.

I have been through 2 full sets, both original and KM2 and on my 3rd now. Even my trailer has them.

G

[Tombie]

How do you figure they'd run with stock springs and not 2" springs?

(This is a loaded question btw)

[Tombie]

If you're going 255-85 I'd suggest getting Ozzy Tyres to get the Toyo Open Country MT in for you...

[Sirocco]

How do you figure they'd run with stock springs and not 2" springs?

(This is a loaded question btw)

Just on full flex, they would stuff into the arches. They are an unassumingly big tyre. I run 2" and never had a rub on full flex even when dislocating springs.

G

[Tombie]

Just on full flex, they would stuff into the arches. They are an unassumingly big tyre. I run 2" and never had a rub on full flex even when dislocating springs.



G



A 2" (or any other) lift doesn't change range of motion... Only static ride height.

They will both stuff to the same point (the bump stop)

[Sirocco]

A 2" (or any other) lift doesn't change range of motion... Only static ride height.

They will both stuff to the same point (the bump stop)



If you run the same bump stops then you do have more motion. A lift physically increases the distance between axle and chassis.

I understand what your saying about the stopping point though. The limiting factor being the bump stops. The lift would allow more movement/flex on the opposite wheel before the bump stop contacted the other side. With lift comes extended shocks.

As an exaggerated example, imagine running 35s on a -2" Spring (assuming they would fit), there wouldn't be much movement!

G

[karlz]

In terms of stability I doubt you would notice any difference. A wider tyre isn't more effective in sand as when you air down the footprint elongates, not widens. 255-285 is only 3cm. Not worth worrying about, not a deciding factor.



Glad you mentioned that. Many people think wider tyres are better.

[Tombie]

If you run the same bump stops then you do have more motion. A lift physically increases the distance between axle and chassis.

I understand what your saying about the stopping point though. The limiting factor being the bump stops. The lift would allow more movement/flex on the opposite wheel before the bump stop contacted the other side. With lift comes extended shocks.

As an exaggerated example, imagine running 35s on a -2" Spring (assuming they would fit), there wouldn't be much movement!

G



Incorrect - you're confusing it with Up/Down travel ratios.

Static ride height - height vehicle sits at normally
Range of motion - the arc through which the suspension can travel

A stock height vehicle that can cycle a tyre its entire R.O.M will be no worse than a vehicle that sits 2" higher Static but has the same R.O.M
The 2" higher will compress a further 2" from static but tyre will still end up at same point.
A -2" starting point will still compress to the same point also, it will have more droop though from its static height.

If a tyre doesn't fit stock, then it doesn't fit with a lift (unless - all bump stops etc have been changed to alter range of motion)

This also applies to vehicles like D3/D4 where larger tyres are fitted, in their case a suspension air failure can result in the vehicle sitting on guards & tyres before hitting bump stops. Imagine a major failure at speed dropping a tyre into a guard at 110km/h....

They never consider that scenario....

[eeyore]

If you're going 255-85 I'd suggest getting Ozzy Tyres to get the Toyo Open Country MT in for you...

I'd be pretty keen to at least price a set of these, but according to an email I had back from Toyo Australia on Friday, they don't bring 255/85 into the country and never have. Interestingly, there are a couple of Australian online tyre retailers who list them as "Sold Out". Maybe parallel imports? Is that what Ozzy Tyres do?

[Tombie]

I'd be pretty keen to at least price a set of these, but according to an email I had back from Toyo Australia on Friday, they don't bring 255/85 into the country and never have. Interestingly, there are a couple of Australian online tyre retailers who list them as "Sold Out". Maybe parallel imports? Is that what Ozzy Tyres do?



Ozzy tyres will order and provide full warranty.
They do as you have noted.

The Tyre is worth every cent!

[frantic]

Ive got/ had them on my 110 wagon for 6 years. With original sagged suspension on stock alloys they where close to touching the rear spring mount. When I lifted it and put in long travel suspension by raising shock mounts and fitting 11.5in travel shocks it rubbed on the rear spring mount. I fitted 30mm spacers effectively making the offset zero and no rub.
Also the def handled/ felt better with the bighorn 255's than the older 235 coopers. And it felt much more planted off road with the spacers, my next set are steel -25mm and probably 315.
The toyo's sound good Tombie as I'm looking to go bigger again soon, do they come in 315 at a reasonable price?

[Tombie]

Yes they cover the sizes you want...

https://www.aulro.com/afvb/images/imported/2016/07/963.jpg

On buy 3 get 1 free at the moment.
https://www.aulro.com/afvb/images/imported/2016/07/964.jpg

[jackdef90]

I just read through this thread, interested to know the answer to toxics question.

So will 255 85 16 fit without rubbing on a stock coiled 90 in my case with no sway bars or not????
Can anyone answer that question with a simple yes or no?

[cuppabillytea]

That's cheap. but he'll need one for a spare as well.

[Tombie]

Yes.. Said it before. Yes. Say it again Yes..

[Toxic_Avenger]

ARE YOU SURE?!
:p

[cuppabillytea]

I don't think he is. i detected an undertone of doubt there. :wasntme:

[Toxic_Avenger]

I think it was the ellipsis...

[cuppabillytea]

And not just one, but two.................