[Joe]

I know you're telling fibs.....I hope

[vet 180]

atari4x4 wrote:

vet 180 wrote:

atari4x4 wrote:

Gwagensteve wrote:

I would expect a 215/80 to outperform a 245 in most off road situations. Interestingly when I joined the Vic suzuki club in 1993, there were a couple of kiwis in the club that swore by 215 80, and ran them on their big cars. I’d never seen them up to that point and have basically never seen them since. Good find though, assuming you can get the construction/tread pattern you’re looking for.

This is the specs on the Toyo Open Country, my only concern is the load rating & all of the tyres in that size have a huge load rating.

Diameter : 30.4”
Width : 8.5”
Rim Range : 5.5-7”
Measured Rim : 6”
Tread Depth : 15.8/32”
Load Range : E - 10 ply
Max Load : 2680/2470 lbs
Max psi : 80 psi
Max Speed : 99 mph
Weight : 39 lbs

The two things i dont like about them are the stiffness and the extra weight. When i searched for my tall and skinny's i managed to find SL rating (despite actully being able to carry more than the LT equivalent) that was light and deformed amazing. With the non agressive AT pattern I ran the the sipping a ability to deform is what made the tire capable.

Problem is in the size you want they will all be hard as rock with a lot of plys as they are tires designed for the duel real wheel 1 ton trucks in the states.

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I've been cross referencing the shit out of tyre specs the last couple of days, and I don't think it's going to be as bad as everyone make it out to be.

As an example I was checking the specs above to a BFG Ko2 in a 245/75r16 & the Ko2 in the common maximum size that people put on NGV's has higher load rating & the same ply rating as the 215/85r16, the 245/75r16 weighs 21.9 kg vs 17kgs for the 215/85r16.

Diameter : 30.4"
Width : 9.8"
Rim Range : 6.5-8"
Measured Rim : 7"
Tread Depth : 15/32"
Load Range : E - 10 ply
Max Load : 3042/2778 lbs
Max psi : 80 psi
Max Speed : 112 mph
Weight : 48.4 lbs

The Ko2 only come in one spec in 245/75r16
LT245/75R16
120/116S E RWL

Well the info you have written sudgests that
The 245 is also a load range E. Therefore the 215 you want would be a better tire and also lighter. Seems a no brainer

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[atari4x4]

235/60r18 vs 215/85r16 (29.1"x9.3"r18 vs 30.4"x8.5"r16)

[alien]

^^ What's the weight difference?

[atari4x4]

Will have to weigh them, but according to the specs the new wheel/tyre combo is 28.1kgs

[atari4x4]

alien wrote:

^^ What's the weight difference?

25.1kgs vs 28.1kgs
235/60r18 vs 215/85r16 (29.1"x9.3"r18 vs 30.4"x8.5"r16)

[alien]

That's not bad considering how much extra rubber you added!

[atari4x4]

Kind of happy with how they look at 12psi, should work ok offroad

36psi


12psi

[Jack]

G’day guys.
Has anyone one had experience with xl7 16inch alloys and how much they weigh in comparison to a 15x7 steel rim??
I’m currently looking into my tyre options, my rust repairs turned guard cut has given me a little more room that expected .
So naturally I’m gonna have to fill those arches now. I was leaning towards some 33x10.5 km3’s ,but considering going to a 16inch wheel to try and get as narrow as I can and maybe save some weight.

[Gwagensteve]

I don't have one to hand, but weight difference will be minimal. I expect the alloy will be slightly heavier.

Going to 16" rims on the basis of lower weight is dubious. a 16" rim is significantly heavier than a comparable 15" rim, and most 16" tyres are load range E, meaning they're heavier (as they have more steel in them)

I you want narrow, you'll want a 7.50 16 (these are available in quite a few tasty tread patterns) but a 7.50 isn't happy on a 7"rim, they're better on a 6" rim.

[Jack]

Thanks for the reply.
Weight saving wasn’t the main reason behind looking into 16’s just a thought I had.
My main reason is trying to get skinny’s, I currently have 30x9.5’s and I don’t really want to go wider.
I didn’t even think of the rims being too narrow for 7.5r16’s which I have been leaning towards in a km3, they look good.
Im a tad confused with the load ratings, I keep reading the 16’s are range E and the 15’s are range C. but on the bf website it’s a number rating and the 7.5r16’s are 116 and the 33x10.5’s are 114 which doesn’t seem all that different. Considering the 16’s are lighter and closer the size i would ultimately like to end up with, it seems negligible. Am I missing something here?

I did have my heart set ons some utv 32x10r15’s but there a little cost prohibitive, I’m not going to be spending $450-600 a tyre anytime soon.

[vet 180]

Jack wrote:

Thanks for the reply.
Weight saving wasn’t the main reason behind looking into 16’s just a thought I had.
My main reason is trying to get skinny’s, I currently have 30x9.5’s and I don’t really want to go wider.
I didn’t even think of the rims being too narrow for 7.5r16’s which I have been leaning towards in a km3, they look good.
Im a tad confused with the load ratings, I keep reading the 16’s are range E and the 15’s are range C. but on the bf website it’s a number rating and the 7.5r16’s are 116 and the 33x10.5’s are 114 which doesn’t seem all that different. Considering the 16’s are lighter and closer the size i would ultimately like to end up with, it seems negligible. Am I missing something here?

I did have my heart set ons some utv 32x10r15’s but there a little cost prohibitive, I’m not going to be spending $450-600 a tyre anytime soon.

Yeah the number and letter are not convertable. For example my old passanger (SL) rated ATs had a higher number and also lighter than a smaller LT rated tire one size down. The letter normally refers to the number of plys (even though radials are constructed differently, but still translates to how much metal is in there) and the number refers to the actual load rating of the tire.

So in KM3 radials a 32x11.5R15 is a pretty similar weight to a 235/85R16. I would imagine a 7.50 would be lighter though

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[greenzook89]

Further onto the 235/85/16 vs 33x10.5 debate.

I'm at the point of pondering bigger tyres. I have 15x7 0 offset and 16 inch XL7 Alloys to mount whatever tyres on.

I'm aware that virtually all 235/85/16 are going to be stiff 10 plys. Would a 33x10.5 be too much tyre for a 0 offset even with NT spacing/WT diffs?

Real world would I notice the difference between the 2?

[tanshi]

Dads were 33x10.5 on 8 inch 0 offset before the beadlocks went on

[Blkfxx]

greenzook89 wrote:

Would a 33x10.5 be too much tyre for a 0 offset even with NT spacing/WT diffs?

From memory I still had clearance between leaf and tyre at full lock and body/front clip mount/crossmember was getting tight when I test fitted mine. But I would have to double check because its been a while since.

[Jack]

Some of the digging I have been doing suggests pirelli scorpion 235/85’s are 6 ply rated and have a much lower load rating than the rest of brands.

[tanked]

I have ordered some tsl 30*11.5s super swampers for my Sierra from the states about 6 months ago now.. Hopefully should see them soon, I have one already and fits on the front and everything just fit and turned
https://www.4wd.com/p/super-swamper-tsl ... TSL+%2F+SX
see how we go when they get here

[Gwagensteve]

That’s an interesting choice. Reminds me of the 31 12.5 BFG’s that were pretty much specifically made for YJ wranglers.

[matt_g]

So, the time has come to replace the tyres I had optioned on my Jimny when I bought it new in 2010 (it only has ~50k km on it), after the rude shock when one of my valve stems split as I was washing the wheel.

The original tyres are BF Goodrich A/T 215 75 r15 (LT and KO are in there somewhere), and they're on the standard steel wheels.

I probably should have replaced them earlier, granted, but now looking at replacement options, there seem to be a lot of complaints online about the KO2 BFGs particularly in terms of wet weather, and then something like this stopping distance comparison:

https://alltyretests.com/kumho-road-venture-at51-test-review/

...didn't seem too complimentary of the BFGs.

The car is used pretty much exclusively as a blacktop runabout, with occasional dirt / gravel roads, and highway runs every couple of months from sunshine coast to brisbane and back. I was happy with my existing BFGs, they looked cool as hell, though mechanics would over-inflate them and you'd end up spinning the rears at traffic lights in the wet.

Those Kuhmos (AT51, or possibly the KL71) were suggested as an alternative to the BFG, which is "out of stock" until the end of the month. The price difference doesn't really bother me, it's more a wet weather / stopping distance safety concern at this point (assuming the 215/75/r15 is going to be the same overall diameter in both brands).

Any thoughts would be appreciated,

Cheers.

[pete_79]

You'll notice some vibration and road noise with the KL71s.
I had these on my Jimny and accepted their less then ideal highway manners for the advantages off road.
Great on scrambly loose shale and clay hills, but if you doing mostly bitumen driving they wouldn't be my personal recommendation.

The AT51s seam to be OK from what I hear and would suit your intended use.
Don't have any personal experience with these, other then I have a set on my camper trailer, if that counts.

[matt_g]

thanks, but i decided to go with the devil i knew, and get the new BFGs - replacing the spare is a bit of a pill (it's been under a cover the whole time, and looks factory-fresh, despite mechanics having been paid to do 5 tyre rotations at least a couple of times), but eh, peace of mind etc.

Anyone know what to do with a pristine tyre that still has the feelers / mold sprews on the lugs?

[Gwagensteve]

OK, some of you will be aware I've been a huge advocate of offroad race tyres for Sierras, ever since I came across the 35 10.5 Baja T/A KR2 in the US in 2014, shortly after they were released.
The 35 10.5 KR2 was designed for class 10 buggies in the US which are lighter in weight and have ~300hp, so they don't need a heavy, wide tyre.

These tyres are well suited to Sierras for a number of reasons:

Softer compounds than LT tyres, more suited to our light cars.
Narrower widths for a given height, resulting in higher ground pressure for more ground pressure and a long footprint for directional stability.
Lighter carcass construction, so they tyres work at higher air pressure.

In 2017, they became more readily available in Australia through BN motorsports, and Gregc bought a set for his sierra, which was previously running 35 13.5 Krawlers. They've performed incredibly well in all terrains, even slick surfaces where conventional wisdom was a swamper or something similarly heavy and aggressive would be required.

I was also running 35" Krawlers*, and as part of a plan to reduce axle breakage and the bulk of the car, I was also looking for a narrower and lighter option.

I priced KR2's which I now consider a proven performer, but they're now very expensive locally. I was also looking at Tensors, which are a little more aggressive than a KR2 and appear to have a bit thicker sidewall, but they're also pretty pricey at ~$600 each.

Earlier this year I had the opportunity to get on board an order for Maxxis Roxzilla UTV/SXS race tyres. There were 32 and 35" offerings, with the option of a sticky in the 35" size, so I bit the bullet.

When I ordered them they'd just won KOH on a turbo SXS, I believe without tyre failure, which is a pretty big achievement. I've just picked mine up.

*A note on Krawlers. There's lots of sets of these in the Vic suzuki club. They were the go-to tyre for us as they were readily available second hand once everyone went to treps etc, they had a relatively soft compound and very flexible carcass by load range C standards. They were also very close to a real 35". Downsides are they are very heavy, and very wide. This means the cars get wide, and whilst they're good for stability, it also means a lot of leverage when you're jammed on a tree or bank. They're also now all ancient. Mine date from 2004-2006, so they're starting to suffer from dry cracking and they're hard.

Here's a quick rundown on the Roxzillas. All pictures are compared to a Krawler with pretty good tread depth. Both tyres are unmounted.



Both tyres are 34" tall unmounted. On a 6" rim at 15 psi, the Roxzillas measure a true 35". New Krawlers also measured pretty close to 35's on rims.


Krawler weight


Roxzilla weight


Roxzilla tread width


Krawler tread width


Krawler sidewall thickness: ~10mm
I didn't get a photo of the Roxzilla sidewall thickness, but it's ~8.5mm



I can't say I've ever seen an 8 ply nylon radial before I'll be interested to see if they flat spot. They definitely crown like a bias ply tyre when inflated.

I'm not aware of anyone running the 35's on a Sierra yet, but there's a few guys on the 32's which measure up as 33" They're performance is very good compared to comparable size swampers and Maxxis Razr.

[Brenno]

Thats a great weight Steve. For comparison, a new 265/75/16 (32" ish) BFG KM2 Mud Terrain is 24kg unmounted.

Can't wait to see how these go. I.would be interested in a 32" model if I didn't have to drive so many km to get to the tracks.

[vet 180]

Brenno wrote:

Thats a great weight Steve. For comparison, a new 265/75/16 (32" ish) BFG KM2 Mud Terrain is 24kg unmounted.

Can't wait to see how these go. I.would be interested in a 32" model if I didn't have to drive so many km to get to the tracks.

They make a sticky and a harder wearing compound

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[Gwagensteve]

vet 180 wrote:

They make a sticky and a harder wearing compound

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The "hard" compound is still very soft by LT tyre standards. If you're used to getting years out of tyres on a Sierra it's going to come as quite a surprise.

I'm accustomed to passing relatively fast wear with Gregc's KR2's but with more tread depth and more void they're going to wear fairly quick.

Also consider they're a nylon tyre rated at maximum load at 18 psi, so you'd need to keep an eye on heat on tarmac lest they fall apart.

[alien]

That's some epic weight loss!!

When I had my Simex's they'd get a flat spot overnight. First 1-2km sounded like I was flying a helicopter and the whole car had a noticeable shudder until they warmed up and rounded out. Given you don't drive yours that often it might be worth throwing stands under the diffs when you park it up (If they flatspot).

[Gwagensteve]

I’ve driven on Swampers since the early 90’s. I’m well across flat spots.

[alien]

But did you ever rock a flat top?

[greenzook89]

Steve, In your experience with them, do the KR2s flatspot?

[Gwagensteve]

I don’t believe so.