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BF Goodrich 7.5R KM3

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Lee MN View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2019 at 6:05pm
Originally posted by masscj2a masscj2a wrote:

 Well aired mine down to 15 psi and plan to run them at this pressure for the duration. Road manners have softened up a bit more. I still think for a ten ply tire, they ride very soft. No so much in the above 30 psi range, but down low, it's working for me. Drove them about 50 miles tonight on an ice cream run. Took it off road for a short spin and that has improved as well at 15. This is not any high value science testing, this is seat of the pants, Hill Billy science. Went up wet rocks on a pretty good grade with mixed wet mud. Damn things never slipped.  Again I didn't bring the GoPro, because I told the little woman it was an ice cream run........oh with a short cut...😁i


Mark, so in your opinion does the 50 lbs weight of the tire effect street performance greatly ?, lug the engine more than your last tire ?

Lee
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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 3:31am
Lee, I was running 29 inch tires with 50 lbs of pressure, so a fair comparison is next to impossible. But with that said, I'm running a brand new rebuilt F head, that's not completely broken in yet, but.....on flat paved roads, performance is pretty good. (Not sure, pretty good is an exact science) but very acceptable to me. I'm impressed with the acceleration and handling. Is it more of a load? Probably, but for me, an acceptable cost for the on road and off road overall performance. I have 538 gears as well. Not sure that helps you, but if you wanted to come take the Jeep out for a drive, come on over. Even the uphill grades are a little better because the added height has helped by keeping me in second gear, instead of shifting into third and bogging down. Now I can comfortably go up in second at 35 mph. I know that makes little to any sense, but prior, this Hill held me to 30 mph in third, with the constant down shift to second to build speed back up.

Edited by masscj2a - 09 Sep. 2019 at 3:37am
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
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steelyard Blues Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 6:19am
Lee,
When I got mine, she had 235-75-15's on her with a split rim. I went back to stock rims and tires. I noticed a huge difference in acceleration and stopping effort in reducing the rotating mass. I believe there was a 25 pound per wheel weight difference. So, 100 pounds less mass.
 
Micah
1947 CJ2A 106327, Engine J109205, Tub 97077. Luzon Red

https://www.thecj2apage.com/forums/steelyard-blues_topic41024_post397981.html?KW=micah+movie#397981

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 11:59am
Thanks for the responses! I’d love to go out east and take a drive but the plane ticket would pay for the tires I’m looking for 3 Willy’s truck rims to complete my set and will most likely pull the trigger before spring Jeep season starts. This past weekend I was doing pre-winter shop/shed cleaning and scaled a few different tires/rims,

1) 6.00x16 ND on a stock Willy’s 4.5” rim = 43 lbs
2) LT235-75R-15 on a 7” wagon wheel = 49 lbs. (current combo)

Lee
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spinnas Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 3:52pm
Originally posted by masscj2a masscj2a wrote:

Spinnas, are you running that 6+5 air pressure on the streets (paved) or just off road ?


I recently lowered to that pressure to get a little more sidewall give offroad and try to soften up the tires some. I was previously at 8-9psi which it did great on road at that pressure. I'll probably only run 5-6psi offroad or with limited road driving cause you can feel the difference in rolling resistance with just that slight drop in psi. My dad has the same tires on his 3A and he runs 7 all around all the time no matter what.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steelyard Blues Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 4:23pm
Lee,
Those truck rims must be a lot lighter than my split rims. I found my old post. I got 45 pounds for stock and 70 for the 235-75-15s
 
Micah
1947 CJ2A 106327, Engine J109205, Tub 97077. Luzon Red

https://www.thecj2apage.com/forums/steelyard-blues_topic41024_post397981.html?KW=micah+movie#397981

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Post Options Post Options   Thanks (0) Thanks(0)   Quote masscj2a Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep. 2019 at 6:13pm
Yeh, I'm looking to do what your dad is doing. Just get them to an all around acceptable pressure and leave em there.
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: 22 July 2021 at 11:04am
Finally got around to mounting the BFG KM3’s onto KH 5” heavy duty wheels, in prep for my next build.
They are exactly 31.5 inch tall OAH.


Sadly these are just too stiff to mount the tires by hand or maybe I just don’t weigh enough ?



Edited by oldtime - 22 July 2021 at 11:10am
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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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeepsterjim Quote  Post ReplyReply Direct Link To This Post Posted: 22 July 2021 at 11:14am
WOW, those look great! Can't wait to hear a report on how the handle.
Jim
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill2A Quote  Post ReplyReply Direct Link To This Post Posted: 22 July 2021 at 11:21am
They look good.
Let us know how well the flex after a few months in action. Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 23 July 2021 at 8:29pm
Got the 235/85R16 Pirelli’s mounted and balanced.
I think I’m going to really like these 6 ply tires.
Much less weight required to balance them.
Mounted and fully inflated on rare set of KH 6”x16” Willy PU wheels.
However these are exactly one inch wider (9” cross section) and 1/2” shorter (31” OAH) as compared to the BFG KM3’s.
They have a nice lip that protects the rim edge from damage.



Edited by oldtime - 23 July 2021 at 8:32pm
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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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2021 at 8:21am
Wow!, both look very nice 👍🏽

Lee
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2021 at 10:46am
If you look at the outermost edge of tread on the Pirelli’s you will see that they are a 2 stage lug design.
The actual tread edges are actually rather narrow so I don’t expect any problems with these tires contacting the front leaf spring.
As I may have stated before the Pirelli’s are the only tire in this size I have seen with a 6 ply rating.
Again it’s Too bad that the KM3’s are so many (10) plies of toughness.
That said I do have experience running the 10 ply Michelin military Jeep tires.
I figure these Pirelli Scorpions to be the maximum tire width used on any of my flatfenders.


Edited by oldtime - 24 July 2021 at 10:55am
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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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pope891 Quote  Post ReplyReply Direct Link To This Post Posted: 28 July 2021 at 11:02am
I thought I would share some information about the BFG UTV tires.  These are 32x10x15 UTV KM3s on a 8.5" wide wheel.  This was taken during the Annual Vintage Jeep Trail Run in NH back in June.  PSI was about 8-10 and I was running trails, rocks, mud and roads all day.  The jeep weighs about 2,700 lbs.  Max weight load for these tires is 1,936 vs. 2,755lbs for the 7.5x16.  They were pretty plush at low speeds over rocks.  They even make a 35" now....


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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 28 July 2021 at 11:10am
How tall do they measure ?
Is that tire an 8 ply rating ?
Wonder how many actual plies ?


Edited by oldtime - 28 July 2021 at 11:11am
Currently building my final F-134 powered 3B .
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Zero aftermarket parts

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pope891 Quote  Post ReplyReply Direct Link To This Post Posted: 28 July 2021 at 11:15am
Oldtime - They are an honest 32.5" in height with 18lbs of pressure.  You will notice they have a "crown" in their tread shape as opposed to a flat tread, which is great for tire clearance on flatties with no lift.  As I understand it, they are 8 ply.  They are not DOT approved.  I'm thinking they are manufactured for lightweight UTVs, not a 2,700 lb jeep, and the sidewall softness reflect that rating.  So I won't be taking any highway off ramps at speed.

Edited by Pope891 - 28 July 2021 at 11:20am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Nothing Special Quote  Post ReplyReply Direct Link To This Post Posted: 28 July 2021 at 6:41pm
BFG load range E truck tires used to have a 3 ply sidewall (they still might, but my info is old).  That was actually more than the 2 plies of typical load range E light truck radials at the time.  I don't know about their current UTV tires, but I'd be pretty surprised if they have more plies than tires designed for a 1 ton truck.

And load range D truck tires are rated for 65 psi.  Load range D is often called "8 ply rated" (but that doesn't mean they have 8 plies, it's usually much less).  These UTV tires are rated around 44 psi, so they aren't the equivalent of a load range D truck tire (which isn't surprising either).  FWIW, load range C is 50 psi, so they are a little below that too.  They are pretty close to the 42 psi of an "XL" P-series tire.  The weight rating is pretty close to an XL P-series too, so that might be the best approximation is a car/truck tire for comparison.
Bob

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Post Options Post Options   Thanks (0) Thanks(0)   Quote EJs1950 Quote  Post ReplyReply Direct Link To This Post Posted: 17 July 2022 at 8:42am
I have been trying to decide on what tire to use.
This post mentions perelli Scorpion tires. I am 
Wondering if anyone one has been using the perelli Scorpion tires.
If so please post information about the tire clearance.
Do the perelli tires hit the leaf springs with stock 
Wheels and no spacers? Also, if in a bind has the tire hit  the tub? 
Any other relevant information will be greatly appreciated.
Thank you for your help. Jeff
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