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BF Goodrich 7.5R KM3

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oldtime View Drop Down
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    Posted: 18 July 2019 at 3:57pm
Anyone on here have a set of these ?
Apparently this size now replaces the older 235/85/16" KM2 tires.
Besides the relatively minor KM3  upgrades it looks like they went from 9.3 wide down to 8.7 OAW !
That's another big plus for the narrow tire guys.
OAH is about the same as before.

The size specs and performance feedbacks I read look great except for that way overkill 10 ply rating which reduces potential tread flex and increases the unsprung weight.

No certainly not as cool looking as miltary tires nor as mud slinging as the NSS but much better for a daily driver that gets lots of miles under all conditions.

I consider this size of tire to be the absolute maximum for an unlifted flatfender.
Eventually I'm hoping to get a set and mount them on Kelsey Hayes 5" HD wheels.




Currently building my final F-134 powered 3B .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AKoller Quote  Post ReplyReply Direct Link To This Post Posted: 18 July 2019 at 4:21pm
I believe I saw that masscj2a ordered a set yesterday. We will all be awaiting his reports.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 18 July 2019 at 4:23pm
Yea 10 ply or even 8 ply is a non starter for me course they would have to be 15" and 29" tall. Due to my 30% OD.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 18 July 2019 at 5:28pm
Here some  interesting YouTube of the initial KM3 reviews..
Currently building my final F-134 powered 3B .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeepsterjim Quote  Post ReplyReply Direct Link To This Post Posted: 18 July 2019 at 10:00pm

Maxxis 30X9.50R15LT Tire, Bighorn - TL1852800



Anyone have or looked into this brand?

Noticing you guys go for 6 ply or higher.   WHY?   Seems awful stiff tires when wanting to air down for traction.  Maybe today's tires are engineered different and give the flex like an old style  4 ply.  

Jim
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 18 July 2019 at 11:04pm
Originally posted by jeepsterjim jeepsterjim wrote:

<h1 ="sku-display-name" itemprop="name" style="font-family: "roboto condensed", sans-serif; color: rgb76, 78, 90; -sizing: border-; line-height: 1.1; margin-right: 0px; margin-left: 0px; font-size: 24px; padding-top: 0px;">Maxxis 30X9.50R15LT Tire, Bighorn - TL1852800</h1>


Anyone have or looked into this brand?

Noticing you guys go for 6 ply or higher.   WHY?   Seems awful stiff tires when wanting to air down for traction.  Maybe today's tires are engineered different and give the flex like an old style  4 ply.  

Jim


All the industry offers in “Tall & Skinny”

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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 12:42am
mine should be here tomorrow. Probably won't be ready to let you know too much until next week. I'm on the hunt for one more KH rim. I have non KH rims, so might have to mount an odd ball. I would prefer non E rated tires, but they do not offer them in anything else. I was indeed looking for an all around tire, for both street and trail. I have bought nothing but KM2's for the last 5 or 6 Jeep's. Love em. Hoping these fill my needs on a stock 3 b. I will let you know when up and running.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rocnroll Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 4:28pm
That IS a good looking tire.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 4:32pm
Sorry bout that Chad i was editting the post. 
Very few good pics of this tire on the web but here's my favorite one so far:
Currently building my final F-134 powered 3B .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 4:54pm
There are very few tall, narrow skinny radial worth considering. 

Prior to this 7.50R-16 KM3 the narrowest were the 215/85R 16's (approx 30.5" tall) and the 235/ 85R-16's (approx 31.5" tall)
So yes this new 7.5 KM3 is now the skinniest radial available.

The KM3 is about 31.5 tall:

And the all important maximum  tread width seems to be about 6.5" maximum:
https://forum.ih8mud.com/threads/new-bfg-km3-thoughts.849861/page-7#lg=attachment1732864&slide=0


Other than this radial my favorite goes to the 235 R-16 Pirelli Mud Scorpion.
Click on tire for more views...


Currently these are my 2 favorite narrow, skinny, radial off-road tires

BFGoodrich 7.50R-16 KM3 

31.5" OAH (actual)
6.5"  Tread width (my best approximation)
6.0" Rim width (suggested)
10 Ply Rating
50.5 Pounds (advertised)

Pirelli 235/85R-16 Mud Scorpion

31.7" OAH (advertised)
7.0"  tread width (actual)
6.5" Rim width (suggested)
6 Ply Rating
42 Pounds (actual)

The Mud Scorpion is the only 235/85R -16 size tire I've found with the 6 ply rating, and so I have a set of them.



Edited by oldtime - 19 July 2019 at 5:04pm
Currently building my final F-134 powered 3B .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spinnas Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 7:49pm
Originally posted by jeepsterjim jeepsterjim wrote:


Noticing you guys go for 6 ply or higher.   WHY?   Seems awful stiff tires when wanting to air down for traction.  Maybe today's tires are engineered different and give the flex like an old style  4 ply.  

Jim
 

Talking to a UTV guy on a run we were on, someone asked him why they run heavy truck tires on their rides. Guy said "it's our insurance policy, you flat one and you don't even know cause it still stands up, which is important cause we don't carry spares". Same principle I guess is why I run 10-ply tires on my flatty. I run them at 7-8psi on or offroad. Ripped a valve stem out on a log once and the tire just looked kinda low, "limped" it back and put another valve stem in. I've never been in a situation where the tire needed to flex more to do what I wanted. Could be just me but that's my thoughts.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeepsterjim Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 8:32pm
good posts guys

Interesting to see what tires are working these days compared to 50 yrs ago BC. LOL

Waaaaaaaaaaay back in the early and mid 60's we would buy military "implement?" 10 ply tires  from surplus stores for about $5.00 ea.  Think they came from some sorta aircraft.  Eventually  upgraded to L-50's, gates commando, Norseman, and Dessert dogs. Stopped using NDT's and Knobbies due to their grave digger tread. Not ideal in the sand.  

Jim


Edited by jeepsterjim - 19 July 2019 at 9:01pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 10:15pm
ups just dropped them off. I'll get a few pictures shortly.
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1966 CJ-6 SBC TUX
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2019 at 10:56pm
Tire Fit :
I run standard suspension and wheels on all my flatties so I want my tire diameter at maximum possible height and  tread width without any body or spring rubbing.

If front tires on a Dana 25 flat fender get any bigger than 31" tall at 6" outermost tread width you will have to reduce the steer angle down to something less than 29* which is the maximum angle  for the Rzeppa axle shafts.
At about 31.5" tall and 6.5 wide I can run 27-1/2* angles (Spicer axle shafts ) without rubbing the leaf springs.

The widest part of the rear treads begin to rub the wheelhouse at full stuff angles at about those same tire diameters and tread widths.
So even if I install thin rear wheel spacers I like to stay below 32" and 7" wide.

Tire Ply rating :
Yes all else being equal the lower the ply rating  the less they weigh then the better they will flex, but also the more they pop.

I have even seen 2 ply rated 6.00 x 16" NDT's but never tried any.
I tried 4 ply tires off the road and I had a 1" diameter branch poke a hole  straight into the sidewall.
I consider 6 ply rating as being the optimum bang for my buck.
I have also run narrow 8 ply and even the no longer available 6.50 x 16  Michelin Radial 10 ply rated Military tires. 
Myself I feel the 8 and 10 ply sidewalls are overkill.

So the 6 ply rating, the tire diameter and relatively narrow width and price are all  big reasons I bought the Pirelli Mud Scorpion radials.
I rather wished that they were narrower yet.
I plan to run those on a future build daily driver that will run ample road miles.

The 7.50R-16 KM3 tires are the exact right size for my preference.
Excepting the Simex Centipede's I believe the KM3's  have the absolute best overall world wide off-road tire reputation.
It's been said that the KM3's were designed for exceptional flex. 
So I suppose the heavy 10 ply rating may be acceptable.





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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2019 at 4:41pm
Here are a few pictures of the new KM3's for the 3b. I guess I will start off by saying, I don't think they need to be a 10 ply tire, but it does have its good and bad points. Much stronger side walls, basically you can run out of trouble with a flat tire.  Air down to nothing and they are supposed to flex some, according to BFG. How much a tall skinny 10 ply will flex, is yet to be determined. I like the lug separation and the roundness of the tread pattern. Finding a tall skinny tire now a days for these older jeeps is kind of a task. My biggest pro for them, is I have run KM2's on everything in the last 5 or 6 Jeep projects and I am never disappointed in their off road or on road performance. Most times I didn't even air down. Lazy, Maybe, but they just worked. Maybe they worked better in some circumstances if I aired down, but when I didn't , they just worked. Last but not least, the price. I ended up paying around $150 per tire and that is including everything. No shipping, no tax. Others are costing much more, to get a tire in this range and when I say range I am including quality, proven performance and company brand. I've run swampers and found that I wanted a softer tire that made less noise on road. They worked great off road but at the sacrifice of the on road performance. And I could not find a radial from them in this price point or size. 


Now for some of the bad. In order to run these on my KH rims or any stock style rim, you MIGHT have to run a tube. The last thing I wish to do is run a tube in a 10 ply tire, on a Jeep that weighs under 3600 lbs. Just don't think I need the extra stiffness. Why do I say MIGHT have to run tubes? Well because I just went to inspect the rims I have and there is some corrosion around the stem hole, so even if I had good sealed up rivets and could get away with a tubeless mounting, now my valve stems would loose air, if they would even inflate. So, tubes and liners would be needed. Not sure that is cost effective or not, because now your adding the cost of tubes and liners.  Another point is ,  these tires are heavy, weighing in around 50 lbs each, they are a heavy weight king. Other similar  tires are coming in at aprox. ten pounds or so lighter.  The height is listed around 31.5 inches, the most I would go on a stock flattie. I have pictures of my 3b fully tucked with 245/75 R16 Eldorado tires and they do not touch or rub. We will see how the 750/16 does later, when I get them mounted. the Eldorado's do not hit the leaf springs at full lock and I am going to assume these KM3's will not as well, seeing as they are narrower than the Eldorado. 

All of this is purely hypothetical . Extensive testing will need to be done, to get exact scientific data. (yeh right, more like hill billy data) I hope to get these mounted this coming week and go out and tell you what I think. I'm really hoping for some good on road characteristics and great off road performance. Obviously there is no perfect tire out there for everything, but I think this addition to BFG's tire line could be good for us slow as you go peeps with flat fenders. We will see. 
 


Edited by masscj2a - 20 July 2019 at 4:46pm
1946 CJ2a Dauntless aka Jalopy
1946 VEC stock
1981 CJ-8 5.3 LS
1966 CJ-6 SBC TUX
1968 CJ-6 225 V6
1974 CJ-6 4.2
1967 M-416
East Coast Modified CJ's
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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2019 at 4:54pm


Edited by masscj2a - 20 July 2019 at 4:58pm
1946 CJ2a Dauntless aka Jalopy
1946 VEC stock
1981 CJ-8 5.3 LS
1966 CJ-6 SBC TUX
1968 CJ-6 225 V6
1974 CJ-6 4.2
1967 M-416
East Coast Modified CJ's
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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2019 at 5:01pm
This is last week with the Eldorado tires on, 245/75-R16's Not much of a evaluation, but right rear is off the ground about 5-6 inches, left rear is tucked and not rubbing, right front is tucked under and not hitting, left front could be lifted off the ground without too much effort. I will drive up on the same rock later when 750/16's are on. Probably going to use the same rims.
1946 CJ2a Dauntless aka Jalopy
1946 VEC stock
1981 CJ-8 5.3 LS
1966 CJ-6 SBC TUX
1968 CJ-6 225 V6
1974 CJ-6 4.2
1967 M-416
East Coast Modified CJ's
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2019 at 5:02pm
Very interesting !
How did you find them that cheap ?
I've not seen them anywhere for less than $177 each.

Maybe you could insert tubeless valve stems with silicone sealer slathered all about.
On the other hand, the tubes may allow you to run sub 6 PSI air pressure.

I don't understand why BFG made them so stiff. 
Typically the 235/85R-16 sized  tires are built in 10 PR since that size is most frequently used for trailers. 
That said I'm not sure why anyone needs a "mud" traction  tire on their trailer.
The 7.50 -16 tires are most frequently available in 8 ply rating because it's an older size that was most often used on half ton pick-ups.

Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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