Mickey T MTZ's are dodgy on Highway

[me3@neuralfibre.com]

I just got a set of 285/75/16 MTZ's fitted to the live axle 100 Series Cruiser. It's got 2" OME lift kit w/ caster correction bushes, good nick OME shocks and OME damper. Front end has winch and 30kg of extra battery weight, so settled OK. Prevous tyres were Cooper AT's 265/75/16 pretty worn. Done about 300,000km I reckon (damn things wouldn't wear out, they came with the car and I am a cheapskate).

The MTZ's turn, stop fine on bitchumen. They are excellent (so far) off road.

Now for the problem. They drive a straight line like a truck with a dodgy steering box. I am forever catching them. They follow every line like a dog follows a smell. The correction is not instantaneous, but needs "overcorrection" to bring them back online, feels like the steering box is worn. Running 32PSI and a full load on board including roof racks, kids etc.

I used to run 42psi, but these at 42 are dangerous. At 32 they are fatigueing, but manageable. Don;t look back to check on the kids, you could end up 1/2 into the other oncoming lane.

HELP: Are they just like this, or are there any tips. I didn't get hte alignment checked as it was fine with the coopers. I'll do that, but am after feedback from others on how you have found them, specifaclly relating to straight line stability. The BF Muddies I had on the surf were not like this. It's not a minor change, this is really bad. I'm going to drop them to 28PIS to see if it will track better.

Thanx
Paul

[nottie]

Have them on the miss pajero and dont have a problem in the world with them. Has reguler wheel alignments and rotations and are inflated to about 35/37 psi. Maybe you have gone right past the sweet point in the psi level when you droped them.
To be honest they are about the best alround tire i have had on a 4by. Followed 2nd by the goodyear MTRs they wouldnt wear out but got really noisy the older they got.

[DIDZ]

Mate, are the front tyres 'Heal & Toeing' At all, Meaning is the tread pattern even all through the tires?? Had front tires heal & toe & drove exactly as you explained.. Front shocks were my Problem..

[choppa1978]

mate i have these on my gu in a 315/75-16 mtz and let me tell u they are the worst on road tyre i have ever had, i put them on 2 days before my melbourne trip REGRET it now im always fitting the wheel to drive straight

[cozzav8]

i have them in 305/70/R16 on my 79 series, deadset no problems, travel dead straight i let go of the wheel and it keeps going straight, they are about 75% wearing evenly and everything

[bogged]

mate i have these on my gu in a 315/75-16 mtz and let me tell u they are the worst on road tyre i have ever had, i put them on 2 days before my melbourne trip REGRET it now im always fitting the wheel to drive straight

What did you have before?

[rvh96]

I have 315/75/16s on both my patrols (2005 gu coil cab ,2006 gu1v 3.0l wagon) and i recon they are the best mud tyre ive driven on road, track dead straight ,steer and brake well and reasonably quiet.I think you may have alignment problems fitting new tyres can aggravate an alignment problem. I run 36psi in mine

[LOCKEE]

How old are the castor bushes and shocks?

Who did the alignment and does it hold alignment?

My 2c.

[TWISTY]

Never had dramas on my old 4runner with 315/70/R17 (35x12.5) MTZs........I do have wandering problems on the 40 with them fitted...but thats all due to its castor being out.

[zagan]

Check out the steering arm bushes, could be worn out.

You'll have feathering along the edges of the tires, if the aliment or bushes are worn out.

[me3@neuralfibre.com]

The 300,000km old cooper AT's that just came off it were worn evenly. No cupping or anything else. Front wears outside slightly more due to cornering. It's had one wheel alignment in 30,000km and still feels the same.
No wear in anything I can find, and the behaviour only appeared when the new tyres went on.

The MTZ's have only done 2500km so far, to early to see wear. Have the rest of Tassie and back to BNE to wear them in some more.

Paul

[InSanE]

i have done a few thousand klm on my lifted gq with 35x12.5x15 mtz and had no problems at all, they are the best mud tyre i have ever owned.

[92mav]

ive done about 25000kms on my 30 12.5 x15 MTZ's and i think they the best tyre i have had on my 5 inch lifted patrol. used to tow every day and i have run them at everything from 16 to 35 psi on the hyway up to 110 km ph and never had a problem. Check your suspension i suspect the problem may be there, as quite often when fitting new tyres we are all often to quick to blame the new tyres when the problem is else were.

Brad

[mud4b]

my 35 on 17 do exactly the same thing, i have just lifted the 80 though and did have problems with caster and a snapped panhard mount, all this is fixed now and it has had a wheel alignment but still will not drive straight at all.

i have also done the front wheel bearings so its not that..not sure what pressure is in mine as i have not checked it but whatever fourbys put in them when they were fitted is still what is in them.

ill see how they go though as i have not driven on them too much.

cheers mark

[sierrajim]

How old are the castor bushes and shocks?

Who did the alignment and does it hold alignment?

My 2c.

Also:

Tyre pressure, have you tried anything between 32 and 42psi?

Correct rim width?

300,000km out of a set of Coopers??

[it works]

I had the same problem with them tracking (following any rut they could find) and i had 1 tyre pealing lugs off i put up with it for 3,000klm i tried lots of things to fix it and even talked to mt about it and got fobed off so i sold them and lost $600 and bought some bf,s and it drive,s good now.

[bogged]

on my 30 12.5 x15 MTZ's and i think they the best tyre i have had on my 5 inch lifted patrol.

Massive 30's with a 5inch lift, PLease post photos, that would be piss funny to see!

[Ryano]

Are they running like this without the load? Have you got a fair bit of gear on the back? Trailer or anything?
This can happen (floaty feel) if you've got a fair bit of gear over the back. Is it on uneven bitumen roads? Get the alignment checked with the weight on board as it will affect the toe setting which can also contribute to the floaty feel. When you get back you may need to get the W/A reset with the usual load onboard.
Being a more aggressive pattern with a squarer shoulder than the Cooper A/T they are a little more susceptible to following truck ruts which can feel a bit like that aswell.
Loaded cold pressure I'd be running probably 38PSI Rear and 35PSI front (If its a reasonable sized load). Having the angle body ply in them, you don't need to run them quite as high as the A/T.

Hope it helps,
Ryano

[STUMPY]

I have done 7000kms on 315x75x16's on my 80 and i'm over the moon with them. quiet onroad and awesome offroad.

[me3@neuralfibre.com]

Further update

Dropped them to 28PSI and is better, not great, but better. I have never run a road tyre this low, and they drive like they are still at 34. They look it too. My gauge is a good one, and I checked it with another gauge. Normally at under 30 I would feel chronic understeer, these seem fine. I'll see how they go at that. Will be monitoring edges for rolling and tyre temps when I stop.

I have tried it with light load (all crap sitting at campsite) and fully loaded, no difference.

Toe won't change with cruiser live axle as suspension moves, only Jeeps do that. You will however get bump steer.

I did try 41, 35, 32. 41psi was simply dangerous on the highway with the MTZ's. I used to run 44 in the Coopers for Brisbane, wasn't great on highway though. Stopped them wearing the edges on corners, held them very square.

Paul

[nottie]

All should read back thru all the posts and see if you get the same result as what i have!

Its a TOYOTA thing

[Suspension Stuff]

I wasn't impressed but maybe I had too much pressure in mine. I know you have to drop the pressure heaps before you start to see any bagging and that is with a 3 tonne Cruiser.

I wish I saw this thread before I drove to Perth via the big rock and back to Brisbane via that Great Ocean Road with 2 tonne of caravan on the back. It made for a scarey trip.

Shane

[RUFF]

If you got 300,000ks out of 1 set of tyres why would you buy a different brand? I find it very hard to beleive its possible to get 300,000ks out of any tire

[Bingham]

73 000km on mine, being 33 equivelents on the patrol and wrapped. will get 80 out of rears and could get 90 out of fronts which is fairly sensational i would say... not bad hey ryano thats even with my driving style!

only drama is bout 60 they started to get a bit noisy.

ate the plenty hiway up 7700 km road trip last month and on a reps car permanantly running hiways with occasional mud sand rock.

so i would look closer at the pressures etc and how your using rubber before writing them off permanantly and factor in i have run a huge range of muddys so think im in a reasnoble position to comment.

[rvh96]

If you got 300,000ks out of 1 set of tyres why would you buy a different brand? I find it very hard to beleive its possible to get 300,000ks out of any tire

thats because it isnt possible, shit you'd be pushing to get that out of the cruiser

[sniper]

hmmmmmm, I was thinking of getting these.........now im a little off put

[bogged]

If you got 300,000ks out of 1 set of tyres why would you buy a different brand? I find it very hard to beleive its possible to get 300,000ks out of any tire

thats because it isnt possible, shit you'd be pushing to get that out of the cruiser

[zagan]

hmmmmmm, I was thinking of getting these.........now im a little off put

I still want a set of these.

My personnal thinking is this:
the guy's wheel aliment is out.
The steering bushes are worn out.
the steering dampner could be shot or getting tired, or is off aliment?
The wearing of the insides is a sign of the caster (I think) being out, the wheel is on a slant.
PSI could be different in each tire?



I've got a pull to left.

I've had an aliment done, fixed it up slightly for a while, it's gotten bad again.
The steering bushes need replacing.
I don't have a steering dampner, but the mounts are there for one so it's been removed I guess.

Before I had the aliment done, the drivers side torsion bar was set 2 inches higher then the passenger side, so I made both the same height, people say/think you should have the drivers side slightly higher to this I think f**k off, either way I don't know nor do I care.

The end result of this the torsion bars being way out of whack, basicly cost me 2 tires it scrubbed the insides of the tires within 6 months and with the steering bushes worn badly made those tires all feathered on the outside if not srubbing the outside of the tire as well.

I'm not expert, but I think this guy should goto a suspension place to get it checked over at least and get some ideas other wise he'll be needing new tires well before 300,000klms.

All I can say check your steering movement by jacking up a front wheel then pull it left to right if it's moving heaps then check out the bushes.

[me3@neuralfibre.com]

hmmmmmm, I was thinking of getting these.........now im a little off put :?

I still want a set of these.

My personnal thinking is this:
the guy's wheel aliment is out.
The steering bushes are worn out.
the steering dampner could be shot or getting tired, or is off aliment?
The wearing of the insides is a sign of the caster (I think) being out, the wheel is on a slant.
PSI could be different in each tire?



I've got a pull to left.

I've had an aliment done, fixed it up slightly for a while, it's gotten bad again.
The steering bushes need replacing.
I don't have a steering dampner, but the mounts are there for one so it's been removed I guess.

Before I had the aliment done, the drivers side torsion bar was set 2 inches higher then the passenger side, so I made both the same height, people say/think you should have the drivers side slightly higher to this I think f**k off, either way I don't know nor do I care.

The end result of this the torsion bars being way out of whack, basicly cost me 2 tires it scrubbed the insides of the tires within 6 months and with the steering bushes worn badly made those tires all feathered on the outside if not srubbing the outside of the tire as well.

I'm not expert, but I think this guy should goto a suspension place to get it checked over at least and get some ideas other wise he'll be needing new tires well before 300,000klms.

All I can say check your steering movement by jacking up a front wheel then pull it left to right if it's moving heaps then check out the bushes.

I'm the guy and
a) I have checked all steering joints and box. No play in any.

b) The damper is the same age as the shocks and they are still performing very well. I judge this with experience as an owner driver of a CAMS spec rally car. Furhter when unbolted it feels fine. I haven't dyno'd the damper, however the damper is designed to prevent oscialltion behavior. This is not an oscllation, it's tracking and poor direction holding.

c) Castor is corrected back to standard with poly correction bushes. Lift is only 2" and is OME kit.

d) Wheel bearings are near new and check fine.

e) The behavior only appeared when the new tyres went on

f) I am very tyre pressure aware. I can pick 2PSI out on the race tyres by feel only. My gauge is accurate and I know what's happening. All pressures are cold.

It's interesting

28PSI front and 34 rear has made it liveable, I am suspicous as to how they cope with wear at those pressures. They are a funny tyre. I would swear from looking and driving they are 5PSI higher than that at least. Must be carcass construction. They don't feel to push understeer as a tyre does when too low in pressure. Remember I am still on trip, so this is all with a full load of camping gear and kids for 5 weeks away. ie. Too much crap.

Finally, overall grip on and off road is still very good.

I'll get an alignment done when I get back home any update with unloaded behavior.

Paul

[Suspension Stuff]

I suspect you get good and bad ones.

As soon as I drove it out I knew there were probs. I should have taken them back straight away but I headed off around Australia just about straight away. I might have got a good set then.

Anyway just letting you know that I had identical issues to the above post.

Maybe there was a bad batch. The apprentice was probably making them wrong.

I don't think we should talk people out of getting them because it seems most people get great results from them.

If it is a continuing problem then this thread will not die quietly.