Outer Limits 4x4 Board

Well almost at the point ready to buy bigger tyres for my jim and was thinking about going a nice skinny tyre (ie skinny swamper 34/9.5). Got a list of good and bads for skinnys, I wanted to know why there would be any other reason to stay with a fat tyre (ie over 10.5) I will be getting twin lockers.

For skinny:
More room to clear the chassis and firewall at full lock.
Less weight of the tyre means less stress on the cv's and bearings?!?!
Able to dig down in the bottom of a bog hole to hit the hard stuff.
Higher, skinny tyre will give more dif clearance and a better approach angle.
they look better in a mini

Against skinny.
Not as much traction over rocks and dirt (big difference??)
Less foot print = more track damage (which i don't think is such a big deal in a zook as say a 2.5t patrol).
Feel less stable on the road and will take longer to brake.

Anything else?

I think you will find on road will be better with a skinny due to less bump steer, but stability is the reason I went with 8 inch rims and 10.5 tyres, I needed width. Wheel spacers and skinny's would be good.

for: lighter steering

Ahh yes lighter steering, handy but too much drama with P/S .

Already have 15 / 7's pushed out about 15mm. Not sure if you can comfortable fit a 9.5 on a 8inch rim but then i could push it out past 25mm. I am not a fan of wheel spacers.

im running 31x10.5 on 7's and theyre great... running them on 8's i imagine they'd be getting cumbersome. i'd love 9.5's though, more bite on the softer stuff =)

I run 31x10.5 on a 15x8 et-24 Speedy rim. I could not be happier with mine.

With an aggressive tread pattern the steering is light and it still drives (and brakes) great on the highway. I cant fault them in the bush (big rocks, dirt, mud etc). They do not scrub anywhere (there is heaps of room at full lock). I am not against a skinny tyre either (they would probably be better in deep mud), but I am very happy with with my wide ones!

I have appreciated the extra width more than a few times now too.

I run 12.5's...On a 8" rim.

I have never driven another 4wd with thinner tyres. So i cant comment on that.

I prob have bumpsteer, but i have p/s. And strong arms from my job.
So all the problems of onroad..Just builds to Suzy's beasty character..

On a sierra there is no downside to a 9.5" tyre - it's already wider than the stock tyres anyway.

34 9.5 swampers provide amazing bite. I've been out with cars with LTB's and all sorts of other stuff and the 9.5's have way more bite.

Steve.

is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

I think all this is very much comparing apples to oranges..

Monkeys to orangutans

I like cola to rasberry.

nicbeer wrote:is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

235/85R16 is around that size (about 32x9.5) if chasing after commonly available radial tyre (i.e. BF Goodrich, Good Year etc. etc.) One of the most common sizes out there also, so not to hard to get hold of.

Then there are the odd ones like a Simex Centipede available in a 32x9.5R15 (or 16) and a JT2 comes in a 31x9.5R16 i think to. Probably something in the Interco range also

BlueSuzy wrote:I think all this is very much comparing apples to oranges..

Monkeys to orangutans

I like cola to rasberry.

not really - Two 6:1 geared, 5.12 diffed LWB sierra with twin lockers and widetrack diffs.

Both cars on the same track on the same day

One on flogged old 9/34's, one on brand new 34 10.5 LTB's.

the car on 9/34's had bite and steering control, the car on 34 10.5's had less bite and less steering control.

That's as close to a scientific test as I could imagine short of putting them on the same car.

Steve.

nicbeer wrote:is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

The 34x9.5s tend to run quite short.
It is more like a tall 32 than a 34 (from the ones I have seen)

love_mud wrote:

nicbeer wrote:is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

The 34x9.5s tend to run quite short.
It is more like a tall 32 than a 34 (from the ones I have seen)

According to the website it is more like a large 33 at 33.8inch on a 15 inch rim. Which is the similar to the rest of the interco range.

http://www.intercotire.com/tires.php?id=8&g=1

I thought they measured in the mid 33s like the 34 LTB and the 32/9.5 simex. 35in silverstones measure 33.5-34in as well.

more important than tyre size, type or width is tyre PRESSURE.

whatever you've got, if you run too high a pressure your not going to get the most grip out of the tyre.

No, I don't agree- It's not more important to have the right pressure than the right tyre.

You are correct that you never get the best out a given tyre at the wrong pressure though.

Most sierra owners run far too much air in their tyres. We did a little experiment and aired down a Q78 tyred sierra by eye - until they bagged nicely.

front- 3.5 psi
rear - 2.5 psi

Just goes to show. My 9/34's get aired to about 8 psi whenever I am offroad, 6 if it's a harder trip.

Steve.

Mud_Muncher wrote:

love_mud wrote:

nicbeer wrote:is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

The 34x9.5s tend to run quite short.
It is more like a tall 32 than a 34 (from the ones I have seen)

According to the website it is more like a large 33 at 33.8inch on a 15 inch rim. Which is the similar to the rest of the interco range.

http://www.intercotire.com/tires.php?id=8&g=1

I measured grimbo's 34x9.5s brand new against the 285/75 bfgs on my GU (they were a true 33) the 34's were easily shorter than the BF's.

Some one else (joey from memory who put the SR20 in the blue LWB) put his 32 simex's up against the 34s and they were again considerably taller. I am sure someone who runs them can give some actual numbers.

Greg how do the 13.5in wide Krawlers go re:ground pressure? Lots of tyre, not a lot of weight?

They're awesome in the dry but on slick stuff theres nowhere ner enough gruond presssure from what I've seen.

Steve.

I have 31X10.5 simex et centerpedes on 15X8 speedy rims with -24 offset. I have no rubbage on the springs and very good stability on the road for such a high and soft sprung vehicle.

I do get a little bump steer and the odd minor death wobble and really slow speed like car parks when I hit a pothole or such but this could be from other issues.

I air down to 9 psi and in the dry I've had no dramas, the tyres don't bag alot due to their stiff nature but they conform over obstacles very well and grip awesome. I did recently have some bead sealing issues during a 12 hour very muddy fourbying trip, but I was not the only one.

It seems the ET's have a bit of a groove due to having rim protectors to allow mud and tiny rocks to work their way in and due to the low (9psi) I was running and the very long difficult trip they eventually started leaking air at the bead and i rolled one off (re-seated quite easily I might add). And had to change another for the spare ( which is a 32X11.5 bfg muddie that does not have rim protectors and hence keeps the crap out better.

So in future In the mud I will leave more pressure in the tyres (probably about 20 psi) to stop the sidewall flexing and letting foriegn matter in the bead so easily until I get some staun internal bead lockers.

But as I said, i've had no dramas holding are or rolling a tyre off a rim on numerous trips in the dry on very difficult tracks of varying surfaces with this combo. I think the issue in the mud has more to do with the design of the tyre not the size but would be less of a problem on a smaller rim of course. My next tyres will probably be simex et's in 32X10.5X15 on the same rims and they are listed as a little wider than the 31 on their website.

love_mud wrote:

Mud_Muncher wrote:

love_mud wrote:

nicbeer wrote:is there anything smaller but still has the 9-9.5 wide? around 31-32ish?

The 34x9.5s tend to run quite short.
It is more like a tall 32 than a 34 (from the ones I have seen)

According to the website it is more like a large 33 at 33.8inch on a 15 inch rim. Which is the similar to the rest of the interco range.

http://www.intercotire.com/tires.php?id=8&g=1

I measured grimbo's 34x9.5s brand new against the 285/75 bfgs on my GU (they were a true 33) the 34's were easily shorter than the BF's.

Some one else (joey from memory who put the SR20 in the blue LWB) put his 32 simex's up against the 34s and they were again considerably taller. I am sure someone who runs them can give some actual numbers.

So does anyone have the numbers on these? I need to make sure that they are a worth while upgrade over my 31's. I am pretty sure they will be .

Don't worry about the numbers. They are a worthwhile upgrade over ANY 31.

Steve.

I thought my worn 9/34's were measuring around the 33 mark but if I remember to I'll measure them.

go the skinny boggers muncher, you know you want to. They'll look sik on the jimny

Unmounted TSL 34" swamper with 100% tread measures 88cm (34") or just over. Hope thats of some help

Swampers are odd things. I had a second hand set of 33's that were well over 33inchs tall, but a mate had brand new set of 36x12.5s on his crusier that were more like 34.5's


Do Bias plys "stretch" as they age ?

love_mud wrote:


Do Bias plys "stretch" as they age ?

I have a recollection that this is the case hence the tyre bible allowing a larger variation in actual tyre size for bias ply tyres.

zookimal wrote:Greg how do the 13.5in wide Krawlers go re:ground pressure? Lots of tyre, not a lot of weight?

On Road - they are spectacular - but who cares about that right

Off Road - they are good, but not great. I'm not sure that they struggle due to ground pressure as much as they struggle due to not having the shoulder lugs of a TSL type tread - but that's going to be due to the conditions that we run down here. i.e. if we were running more rock rather than slippery rutted hill climbs, then it could be a different story.

They are now sitting on beadlocks, so where i was previously running 8psi, i will take them down to 3 or so and see what happens (if the car ever gets out of the shed again)...

Regardless - they look cool

greg wrote: if the car ever gets out of the shed again...

They are awesome in the shed....