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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 208

United Kingdom 
285 265 and Offset
I saw the thread on how to measure off set which I will later.

What is the most sensible amount of offset before it affects handling?

285 tyres, do they degrade handling at all? I'am looking at putting Insa Turbo Special Tracks on as the current wheel/tyre combo I run is awful.

I drove it at the weekend and reminded me I need to change.

I forget I had a set of 16" steels tucked away so now going to put some tyres on them.

currently the 33 13.5 15 grab every camber and rut at low speed and pull me about badly. Plus they have large off set.

So looking to put the right wheel / tyre combo on. I tried some 235/85/16 and drove fine but it looked awfuly because I have a lift and challenge wings, hence wanting to go as large as sensible.

So nearly ordered 265/75/16 as they are cheap and fit...but tempted by 285/75/16.

I have read the threads.. and more threads...and googled things but ned to confirm before I order them.
Post #573056 24th Oct 2016 10:01am
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
Offset doesn't really affect the handling that much, it just affects how far (or not) things stick out. It does affect the steering lock, the stability and the amount of mud up your doors. For the most neutral handling you want the centre of the tyre around the pivot point of the steering and that's also kindest on the bearings but I don't think anyone really worries too much about that.

Suspension lift, particularly if done badly, will significantly affect the handling. Obviously you're raising the centre of gravity and also changing the steering geometry.
Tyre width will affect handling, with wider tyres it will tend to wander more and be harder to steer. Wider tyres also have a higher rolling resistance (on and off road).

Whatever you do, if you're using Special Tracks the handling is going to be pretty awful, I've got a friend with them and you can hear him coming from miles off too. What are you actually going to be using the vehicle for? If it's just a quarry basher then great but I'd think twice before putting them on a general purpose Land Rover.

Another tyre size that might be worth considering is 255/85R16 which is the same height as the 285s but a bit narrower. That's about a 33" tall, 10" wide tyre. BFG, Maxxis and a few others do mud tyres that size that will all be more manageable on the road than Insa Turbos. Again the narrower ones might look silly in large arches though.
Post #573075 24th Oct 2016 10:42am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17428

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
You might want to have a read of the quote below, taken from a discussion on wheel spacers (http://www.defender2.net/forum/topic9013.html). Whilst it is about spacers, it does shed some light on the intricacies of steering geometery.

Bear in mind that all spacers do, geometrically speaking, is change the offset.

285s do and will feel different to 265s, but probably not hugely different. Generally fitting wider tyres, or otherwise altering the scrub radius, will make the vehicle more "skittish", prone to "tramlining", and suceptible to other road-surface-defect-induced odd behaviours.


blackwolf wrote:
As stated above, wheel spacers won't affect your wheelbearings any more or any less than wheels with an equivalent changed offset. It is just another of those urban legends that they will.

Unless you opt for a very thick spacer or hugely different offset wheel, the increased loadings on the suspension components should be negligible.

The only aspect of the steering geometry that will be affected is the 'scrub radius', which is a function of the steering axis inclination and camber angle. The scrub radius is the distance between the point at which a line drawn through the centres of the top and bottom swivel pins instersects with the ground, and the line along which a plane through the rotational centre of the tyre intersects with the ground (which is generally outboard of the steering axis interstection point).

The scrub radius will increase if the tyre is moved outwards, either by use of a spacer or by use of a wheel with reduced (ie "more negative") offset. However, the scrub radius will decrease is a larger diameter tyre is fitted without changing the offset, since the act of raising the axle further from the ground will move the intersection point of the steering axis and ground plane outwards. Fitting a wider tyre of the same diameter to a wheel of the same offset won't affect the scrub radius at all, since the increase in tyre with is shared equally on either side of the rim.

The result of this is that fitting spacers and larger tyres will actually affect the steering geometry less than fitting spacers without fitting larger tyres.

The effect of increasing the scrub radius is that the vehicle will be more affected by changes and irregularities in the road surface; for eample, it may be more prone to 'tramlining' in lorry-ruts on motorways, more prone to a wobble when crossing white lines; that sort of thing. When I bought my 07 DC it had 285/75s already fitted on standard Boosts without spacers, and I fitted 30mm spacers as soon as I reasonably could (principally because the turning circle was unbelievable!). I found that the steering performance and handling improved afterwards.

One thing to bear in mind with spacers, especially thin ones, is that the hub/wheel interface may not be as strong as before, and this is probably the area of most concern (and the reason why spacers are not allowed in motorsport). For the spacer to work, the spacer must be bolted to the original wheelstuds and the the wheel bolted to studs fixed in the spacer. Therefore (a) the spacer must be of adequate strength/thickness to mount the new studs securely, and (b) the spacer must be think enough to accomodate the full length of the original wheel-studs AND the thickness of the nuts holding it to the original studs within the thickness of the spacer. With thin spacers, there is relatively little material left to secure the spacer after it has been counterbored to accomodate the nut. I don't believe that any reputable manufacturer makes spacers for LRs which are less than 30mm, and this is the reason.

There is no reason why any of the nuts should ever come loose. There is another urban legend that says the nuts should be threadlocked, but this is not a good idea. If the threads are kept clean with just a hint of copper-grease, and the nuts are torqued correctly, the nuts will not loosen.

Many insurance companies will frown upon the use of spacers and it is not clear why. It may be that they are too ignorant to understand them fully, or more likely they have stats whcih show that cars with spacers fitted are more likely to be involved in accidents than those without, which is probably true in the case of the Corsa-Kiddies but not 4WDs. A specialist insurer should be OK with them.
Post #573077 24th Oct 2016 10:45am
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
And this is a classic example of why I should have just waited for an answer from blackwolf Laughing
Post #573099 24th Oct 2016 11:39am
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 208

United Kingdom 
Cupboard wrote:


Suspension lift, particularly if done badly, will significantly affect the handling. Obviously you're raising the centre of gravity and also changing the steering geometry.

Whatever you do, if you're using Special Tracks the handling is going to be pretty awful, I've got a friend with them and you can hear him coming from miles off too. What are you actually going to be using the vehicle for? If it's just a quarry basher then great but I'd think twice before putting them on a general purpose Land Rover.

Another tyre size that might be worth considering is 255/85R16 which is the same height as the 285s but a bit narrower. That's about a 33" tall, 10" wide tyre. BFG, Maxxis and a few others do mud tyres that size that will all be more manageable on the road than Insa Turbos. Again the narrower ones might look silly in large arches though.


Thanks for the Reply Cupboard,

Suspension is lifted slightly, I removed the blocks that had been added and it is better.

I've heard the Insa Turbo Special Tracks are an amazing off road tyre & I can live with road noise.

Its the handling which is important to me. I dont expect car like handling but dont want it pulling hard across road.

The tyres I have now are aggressive so don't want to loose off road performance. It is mainly green lanes and a few off road events.
Post #573151 24th Oct 2016 3:31pm
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Bps



Member Since: 14 Feb 2016
Location: Lancashire
Posts: 832

United Kingdom 
I have had issues with handling with tyres on a 10" rim and big offset. Going to a 8" rim and less offset cured all issues. Personally I wouldn't ever drive on the road on insa turbos ever. Noise, handling and wet grip were horrendous.
Post #573165 24th Oct 2016 5:28pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 208

United Kingdom 
blackwolf wrote:
You might want to have a read of the quote below, taken from a discussion on wheel spacers (http://www.defender2.net/forum/topic9013.html). Whilst it is about spacers, it does shed some light on the intricacies of steering geometery.

Bear in mind that all spacers do, geometrically speaking, is change the offset.

285s do and will feel different to 265s, but probably not hugely different. Generally fitting wider tyres, or otherwise altering the scrub radius, will make the vehicle more "skittish", prone to "tramlining", and suceptible to other road-surface-defect-induced odd behaviours.



Thanks Blackwolf.

Hopefully I have understood this correctly.

Checking the wheels I have fitted the offset is 30mm. The tyres are 13.5" wide.

From a previous thread I understand my tyres are bias ply not radial....I have not got stuck yet which is nice.

So...If I change to wheels with 0mm off set which I have should I fit 265/75/16 or 285/75/16..the 265's are certainly cheaper.

I don't want to use spacers.

The effect of scrub radius sounds like what I'am suffering
blackwolf wrote:
"more affected by changes and irregularities in the road surface; for eample, it may be more prone to 'tramlining' in lorry-ruts on motorways, more prone to a wobble when crossing white lines"


It pulls the steering with force quicker than I can react and sometimes on breaking.

I have changed wheel bearings, track rod ends, drag rod ends, new drag bar and steering bar and re-tracked it.

Not changed front radius arm bushes.

50-60mph is fine. Low speed is awful.

Would be nice if I could try many combinations before buying!

Thnaks for your advice, much appreciated. Thumbs Up
Post #573180 24th Oct 2016 7:08pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 208

United Kingdom 
Bps wrote:
I have had issues with handling with tyres on a 10" rim and big offset. Going to a 8" rim and less offset cured all issues. Personally I wouldn't ever drive on the road on insa turbos ever. Noise, handling and wet grip were horrendous.


I spotted someone the other day with deep wheels & big tyres and asked him how his handled....badly was the answer. He had cranked arms and looked setup just still did'nt drive right.
I think mine are 10" deep 30mm offset.

...I have never driven on Insa Turbos, but three people I know use them and really rate them. Two on Land Rover 90's and one a Discovery....I guess they are what they are for the price...I can live with noise but if they pull about I'm not wanting them.

I guess wet grip will be low as low area in contact with road...I drive pretty steady in it to be honest....same off road I like just crawling along through the mud without having to go hard.

I have some 0mm steels to fit just need to find the tyre. I think they are 8" wide wheels.

What size Insa's did you have?

Thanks for replying Bps, and your help.
Post #573181 24th Oct 2016 7:20pm
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Bps



Member Since: 14 Feb 2016
Location: Lancashire
Posts: 832

United Kingdom 
They were either 265 or 285 I can't remember as it was a few years back. Bias ply are not the best on the road. Are you runnning mudzillas or Treps? I'm on 35" km2's.
Post #573187 24th Oct 2016 8:09pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 208

United Kingdom 
Bps wrote:
They were either 265 or 285 I can't remember as it was a few years back. Bias ply are not the best on the road. Are you runnning mudzillas or Treps? I'm on 35" km2's.


They are Maxis Mudzillas. Seem great off road, today & yesterday I done a track nearby very sticky and big ruts and just went through in 2nd..no wheel spinning..just drove through...thats why I really like them! I hate changing wheels about though so want one wheel/tyre for all!


KM2's look nice. The Mudzillas have nice sidewall tread blocks too! Handy when its tilting over in ruts Very Happy
Post #573203 24th Oct 2016 9:09pm
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Cupboard



Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

United Kingdom 2011 Defender 110 Puma 2.4 HT Corris Grey
For green lanes I don't think you need anything more than an all terrain pattern, if the lane is bad enough to need more than that then I think you should be leaving the lane so it's not too damaged for other users and so it can recover when it dries out. Churning up public rights of way with aggressive tyres just gives the rest of us a bad name.

For off road events, depends what you're doing I guess.
I've driven past vehicles on Special Tracks with my Michelin Latitudes at pay and plays, partly because I was at fairly low tyre pressures and partly because they were driving like complete idiots. I'm not saying you should buy Latitudes, from what you've said so far I don't think they're the right tyre but my point is with a bit of not being an idiot you can get further than you might think with a less aggressive tyre.

I think I'd be going for the KM2s or some of the Cooper STT Pros. Both available in 315/75R16 and 285/75R16 or the KM2s in 255/85R16 for a skinnier tyre. Obviously the bigger you go (width or height) the worse it will handle, personally I don't think Defenders are heavy enough to warrant the wider tyres so I'd choose the 255s. Opinion is varied about whether or not you need a lift, some say definitely some say definitely not. I've had 255s with no lift but never got it properly articulated with them. I'm pretty sure BW doesn't have a lift and he uses 255s, plenty of others do too.

Insa Turbos are not general purpose tyres, they're good pay and play tyres.
Post #573457 26th Oct 2016 7:54am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17428

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
I use 255/85 KM2s on Blindos with no lift and no problems, althoughI had to trim a tiny sliver off the inside lower edges of the rear flares. Before that I ran 285/75 KM2s on Boosts with 30mm spacers, and the steering was much less predictable.

I second what Cupboard says with one tiny modification - if your tyres are any more aggressive than KM2s then stay off unsurfaced rights of way. You will simply attract unwanted criticism fro the antis and accelerate the closure of all unsurfaced vehicular rights of way.

Incidentally, the road manners of Insa Turbos are likely to be so dreadful than the offset ect is likely to be irrelevant, and their performance on wet tarmac will be marginal. I would only consider them on a vehicle which spent 90% of its time off-road on private land.
Post #573476 26th Oct 2016 9:18am
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