Outer Limits 4x4 Board

Last week I recieved my new MT117 - 285 85 16's. They are 900mm diameter so equivalent to 35.5" and 11.2" wide. These are my actual measurements. The actual tread with is XXXX (will update this when i measure it).

http://www.silverstone.com.my/tyre_mt117.asp

MY VEHICLE:

My car, 308 MQ patrol 4sp, with 2" body and 2" spring lift, and front springs sagging a little.

WHAT I KNEW:

Before buying the tyres i did what research I could on these. They were by far the cheapest 35's I could find so this almost made the decision, however they were 16" and I didn't have any 16" wheels, but the price of the tyres and wheels was still less than 35" Cooper STT or Goodyear MTRs and these were more agressive and head more tread depth.

I have read what limited information I could find on these tyres and bascially it sounds like they have very stiff sidewalls and require lower pressures than normal to get the same buldge in the tyre. This could cause problems with the tyre slipping on the bead. Other than that, it seems they have a soft compound which may wear quickly on road but I can live with that.

There are a few deriviatives of MT117, these are obviously quite different to the extremes, however Silverstone offer a MT117 Sport which is the 285/75 16 size tyre (33") which has a more rugged looking sidewall, otherwise quite similar to what I would call the "original" MT117 I bought.

ABOUT THE TYRE:

These are Tube Type tyres and I only bought 4 (no spare) and would plan to get a old 35 or 36" tyre as a spare in the future. I grabbed a spare tube and bought some tyre irons just in case and last resort would use my old 31" tyres a spare.


The tyre is actually curved, so on road you sit on the centre band and the two inner lugs mostly. Using my infrared temperature gun this confirmed it, sitting at around 33 deg c on the inner band and down to 25 deg c on the outer lugs.

They weigh 43kgs on 16x8 steel rims, vs 34kgs of the old 31's on 15x8s. Tread depth in centre lugs, 17mm, outer lugs, 22mm.




INITIAL DRIVE,

OK, first thought, these are loud. I have a loud V8 and a even louder whiny gearbox but these do overcome the whine of the gearbox at about 60kmh. As you continue up to 80 the noise drops off and then about 100kmh youre listening to a nice hum from the tyres. Can live with this.

Pumped up to 36 psi (as the firewall states max psi, might go a bit lower to allow for heat increasing the pressure) they are very squidgy compared to 31" AT's I used to have. Around corners there is a fair bit of body roll now, it seems to roll into the corner and sit there until you roll out of the corner. It was a little unnerving at first but once you are used to it, seems ok. It does wander quite a bit, especially on bumpy roads.

At 100kmh-110kmh freeway driving seems to travel along ok, still wanders a bit and there is a bit of vibration over 100kmh, im assuming due to the difficulties balancing tyres this size. There is fair bit less noise from the engine now the car is sitting on 2700rpm at 100kmh instead of 3300rpm, which was just as the cam comes on and starts to make decent noise.

Fuel economy has increased a little, was perhaps 25-28 L/100 on road (LPG), now up to 30. I contribute this to the car now sitting off the cam, at lower revs, and being a v8 has plenty of torque to sit at these revs easily with 35.5" tyres. All in all im happy the fuel economy has not changed very much.



BEFORE OFF ROAD:

I had it on ramps to test the flex before i took it bush for a test drive and it also looks like the stock front bump stops won't need modifying to keep the tyre off the top inside of the guard. Does come close to the lip of the flare at the bottom of the guards.

All in all easy mods to fit 35's on these cars.


OFF ROAD

In the bush it scrapes a little on the front of the guard over humps and in some ruts. It just scrapes the inside of the tyre on the spring at full lock however i can live with this also. Will remove the flares and cut the guards sometime soon however it seems ok for the moment.


FIRST TRIP:

We went up through Sheepyard/Wonnagatta to Bright last weekend and I had aired down to 25PSI and once we were at the top a further 2-3psi to keep it at 25psi. Even at 25psi there is bugger all buldge in the tyre.

I got 166kms out of my first 90LT of LPG, equates to 54L/100. MOre than 1/2 the driving would be at less than 20kmh average speed and the rest 20-60kmh dirt roads.

It wasn't wet, so had no issues with traction, didnt really get to test out the tyres very much.

When I was installing the tyres, I noticed one tube wasnt in the correct position and the valve was on an angle. Now once back to the servo at Myrtleford to fill up with air and gas, we notice the tube has slipped further around and the valve cap is touching the inside of the valve hole and is jammed on.

So to cut the story short, we ended up mangling the valve and had to change the tube in the driveway of the servo. Better to happen there rather than on the track I guess. From now on I dont't think I can go less than 30PSI until I get beadlocks.

Another tyre has also slipped around a little however it is still ok to pump up.

CONCLUSION:

Lots of tread for the price. Can't air down much means won't be that useful in the snow. Should have enough traction at higher pressure for mud however be nice to air down in the mud too. My fear is that because these are thinner than your average 12.5" tyre you are at further disadvantage since you can't air down very much.

Pretty noisy and not that nice to drive on road. It is suitable for a weekend truck such as mine. I wouldnt want to drive it every day.

Seriously considering bead locks now.

All in all, every time I look at my truck it makes me smile. Will update when I have had it in some decent mud.

QUESTIONS:

1: What can I do besides beadlocks to prevent the tube rotating with the tyre?
2: I have some standard 7.5" x 16 tubes at the moment. What are the options for heavy duty tubes?
3: What is available as patches for the tyre, incase i spike a large hole in the tyre for example, I can remove the tyre, patch it with some rubber and put a new tube in to keep goign. Where do i get such patches?

Hey Juls

I've had these tyres before on my old winch truck (Rangie) and they are the best value for money mud tyre you can buy IMHO. We ran standard tubes, offset Disco rims and regularly aired them down to below 10Psi to get sidewall bulge and the tyres were indestructable. We never experienced the tyre rotating on the rim, we never damaged a sidewall regardless of how poorly I drove and we never had any problem with them at all.

You can buy heavy duty tubes if you want them but that's up to you. The only real problem about havingjust one spare is that the tyres are directional and, as you probably already know, they aren't real good when running backwards. Particularly on road, they are all over the place when running backwards.

One thing we did do was groove the continuous centre tread (using the existing small recesses in the side as a guide. This allowed the tyre to bite far harder than they could do with the continuous centre rib.

Cheers
Simo

why do you want the tire to bulge out? that's just asking for sidewall stake's. When aired down, you want to extend your footprint! skinny tires for mud, wide for rock.

just out of curiosity, what is the actual tread depth on these?

Cheer's

Simon

Simo, thanks for your reply.

I will have to experiment with lower pressures then and keep an eye on it. At least they aren't hard to pop off the rim and reset the tube placement if it does rotate.

I had heard of people grooving the centre rib and definately something im considering..

Shakes, I guess by sidewall buldge I mean airing down to increase the contact patch.

Actual tread depth (measured with my verniers) is 17mm as Silverstone said. The outer lugs are 22mm i think, (I have it written down at home)

Simo,

Do you know what size tubes you were running?

The ones the tyre place installed for me are 7.0/7.5 x 16 however talking to my local tyre bloke he reckons they are too small.

This could be why the tyre was rotating on the rim.

Any thoughts?

I have some of these also, I run front on 14 psi and rear on 12 on a GQ.

I have spun the 2 front tyres, both at the same time while winching the ute off a big rock (both centres on it and all wheels in air) as the tyres were grabbing at the next rock.

I will be beadlocking these this week end, they are now the girls play tyres.

Very good value tyre.

why didn't you get the normal ones??

my mate has the tubeless 33's on his patrol, brilliant tyres
285/75/16 MT117Extreme's

they don't bag out on the sides, but the footprint length increases- 13PSI in mud and sand, 17PSI on rocks, 20PSI on corrugations

I have had mine around 5 years, we are thinkin of the smaller radials for drive tyres on the girls car also.

juls wrote:Simo,

Do you know what size tubes you were running?

The ones the tyre place installed for me are 7.0/7.5 x 16 however talking to my local tyre bloke he reckons they are too small.

This could be why the tyre was rotating on the rim.

Any thoughts?

Sorry mate can't remember (had too many Bundy's tonight). I recall they weren't a cheap tube but other than that, I've got nothing in the memory banks re the size ... sorry However I don't think 750x16 tubes are big enough though so you should look for bigger tubes I would think.

And to answer Shakes response re why you would air down, yep you are right. I aired them down to bag the tyre out and increase the tyre contact patch. I was competing in winch challenges that provided a large variety of surfaces from rocks to mud and when aired down to 8 or 10 psi these tyres would bag beautifully and grab hold of and climb over just about anything you could point them at. In fact they were so good at traction, I managed to roll the Rangie over backwards with these tyres fitted, but that's another story. I can tell you that regardless of how poorly or how hard I drove the vehicle I never damaged or even scratched the sidewalls on these tyres. They are seriously tough tyres IMHO.

I know other winch challenge competitors who were also using these tyres at the same time I was and they also aired down, some as low as 6 and 8 psi. I do not recall these guys damaging a sidewall either. Seriously, these tyres are tough.

Anyway, you have purchased wisely Juls IMHO, these are the best value for money extreme type tyre on the market. I cannot deny that there may be better extreme tyres on the market but they cost twice as much as the Silverstones. I would recommend you groove out the centre rib as this allows the tyre to dig in more and also allows the whole tyre to contact the road as the centre ribs can deflect/deform enough when grooved.

Just as an aside, I have also had a vehicle fitted with the MT117 Sports (or radial version whatever they are called) and these were a brilliant tyre as well. I purchased this vehicle from a mate who had them fitted new and had travelled something like 30,000 kms or more (from my pissed and failing memory) and they were still good for another 30,000. And he wasn't particularly easy in tyres. Silverstone make great value for money tyres IMHO.