Narrow 34" tires
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
He means that the truck is lifted so that the bottom of the body is higher than the tops of the tires...its too tall.
Like viewed from the side...you can see under the truck from the tops of the tires, down.
Like viewed from the side...you can see under the truck from the tops of the tires, down.
JK Super Freak
Joined: Nov 2007
Posts: 1,259
Likes: 0
From: Massachusett
I found a state by state calculation for max lift and wheel height. Here is the URL, Please remove if this is against any rules...
http://www.offroaders.com/info/tech-.../lift-laws.htm
For Mass :
Get out your calculator: The maximum allowable mechanical lift (as well as what's acceptable in terms of bigger rubber) can be determined by this formula:
Maximum Lift = Wheelbase x Wheel Track / 2200
For example, if you did that formula and came up with 2 inches, then a 2-inch lift and a 2-inch increase in tire size is allowable, equaling a total lift of 4 inches over stock.
http://www.offroaders.com/info/tech-.../lift-laws.htm
For Mass :
Get out your calculator: The maximum allowable mechanical lift (as well as what's acceptable in terms of bigger rubber) can be determined by this formula:
Maximum Lift = Wheelbase x Wheel Track / 2200
For example, if you did that formula and came up with 2 inches, then a 2-inch lift and a 2-inch increase in tire size is allowable, equaling a total lift of 4 inches over stock.
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
Those poor SWB bastards, they don't stand a chance.
:(
2.68" max lift.
Lets see, Throw some 35's on there, 3" taller diameter than 30's...that's 1.5" of lift...Got damn near 1.16" left.
Hmmm....maybe a set of 33's for a 0.5" lift, and a 2.5" BB?
:(
2.68" max lift.
Lets see, Throw some 35's on there, 3" taller diameter than 30's...that's 1.5" of lift...Got damn near 1.16" left.
Hmmm....maybe a set of 33's for a 0.5" lift, and a 2.5" BB?
Last edited by TEEJ; Dec 10, 2007 at 06:02 PM.
Thread Starter
JK Enthusiast
Joined: Sep 2006
Posts: 121
Likes: 1
You need to get a copy of 540 CMR 6.00 authorized by M.G.L. c.90, s 7P
My Dodge Ram gets questioned every year during inspection because it came from the factory with rear blocks between the axle and sprig.
Of course, there are always places that don't bother you no matter what you have.
The fact is the law and regulations and if you violate it and there is an accident, your insurance company can use the violation as a reason to not honor your claim.
Basically, you get the following:
You may increase the wheel track by 4" max.
Using the wheelbase and track, run the following formula:
(WheelBase in INCHES * Track in INCHES) / 2200
ALL FRACTIONS ARE REMOVED. No rounding allowed.
The number you get from the formula is used as follows:
1) MAXIMUM Mechanical lift. (Suspention, Chassis, or Body Lift.)
2) MAXIMUM Tire size increase over OEM Maximum tire offering.
And then here is the place that idiot lawmakers contradict themselves:
"The maximum combined mechanical and tire lift shall be no greater than the sum of the maximum mechanical lift and increased tire size calculated for the particular vehicle."
So, which is it? Tire size = OEM+Formula or Tire Lift = Formula?
The next paragraph then creates an example which is different again claiming that a 65" wide and 105" long vehicle would allow a door height change of only 4".
So, who knows what the actual intent is. The way I read it is use the formula to set lift and tire size increase. However, you can argue that your total lift as measured from the door would be double the formula as a "Tire lift" would allow a tire size increase of almost double the formula result.
This is where the One Inch "Fudge Factor" exists. Since the CMR isn't clear, so long as you are in the 'ballpark' it isn't worth the court's time to argue.
Here is the entire CMR for your reading:
540 CMR: REGISTRY OF MOTOR VEHICLES
540 CMR 6.00: ALTERATION OF MOTOR VEHICLE HEIGHT
Section
6.01: Purpose
6.02: Scope and Applicability
6.03: Definitions
6.04: General Requirements
6.05: Maximum Combined Mechanical and Tire Lift
6.06: Violations
6.01: Purpose
(1) The purpose of 540 CMR 6.00 is to provide rules and regulations for altering the height of four wheel drive motor vehicles by elevating or lowering the chassis or body more than two inches above or below the original manufacturer's height.
6.02: Scope and Applicability
(1) 540 CMR 6.00 is adopted by the Registrar of Motor Vehicles under the authority of M.G.L. c.90 s. 31 and pursuant to the provisions of M.G.L. c.90, s 7P to regulate alterations to the height of four wheel drive vehicles with an original manufacturer's gross vehicle weight rating of not over 10,000 operated on any way as defined in M.G.L. c. 90, s. 1.
6.03: Definitions
Four Wheel Drive Motor Vehicles: Any vehicle that is capable of providing torque to all four wheels.
Mechanical Lift: Modification to the chassis, suspension or body by any means exclusive of tires, rims, and load, affecting the height of four wheel drive motor vehicles.
Original Equipment: Any items of motor vehicle equipment, including tires, which are installed in or on a motor vehicle, or available by option for the particular vehicle from the original manufacturer at the time of its delivery to the first purchaser.
Original Manufacturer: Any person engaged in the manufacture or assembly of motor vehicles for delivery to the first purchaser.
Original Manufacturer's Height: The highest distance inclusive of the largest tires and highest suspension available as standard or optional equipment for the particular vehicle from the original manufacturer. The distance shall be measured between the lowest edge of the center line of the operator's door, or to the lowest point where the door would meet the body on vehicles without doors, or to the lowest point on the floor panel directly below the operator's position on vehicles designed without doors, and the level surface on which the unladen vehicle rests, as determined by the Registrar.
Reconstructed Motor Vehicle: Any four wheel drive motor vehicle constructed or ass3embled principally with used parts or components.
Wheel Base: The shortest distance between the center of the front and rear axles.
Wheel Track: The shortest distance between the centers of the tire treads on the same axle. On vehicles having different axle widths, the measurement shall be made on the widest one.
6.04: General Requirements
(1) No motor vehicle shall be altered or modified in any way that may cause the vehicle body or chassis to come in contact with the roadway, expose the fuel tank to damage from collision, or cause the tires to come in contact with the body, chassis, or steering components under normal operation. The horizontal plane, front to rear, shall not differ more than two inches.
(2) Alterations or modifications to the original braking, steering, or suspension system, which result in the impairment of the safe operation of the motor vehicle, are prohibited. All replacement parts and equipment used shall be designed and capable to perform the function or purpose for which it is intended and shall be equal or greater in strength and durability than the original parts provided by the original manufacturer.
(3) The wheel track may be increased by the use of tires and rims for a maximum total increase of four inches beyond the original manufacturer's specification. The use of spacers to increase the wheel track is prohibited. Fractions shall be excluded in all measurements and final calculations.
6.05 Maximum Combined Mechanical and Tire Lift
(1) The maximum mechanical lift for four wheel drive motor vehicles shall be calculated by multiplying the wheel base times the wheel track, and dividing the product by a safety factor of 2200:
i.e., 92" w/b x 58" w/t = 5336/2200 = 2" (maximum mechanical lift).
The outside diameter of the largest tire size available from the original manufacturer as standard or optional equipment for the particular motor vehicle may also be increased up to an amount equal to the maximum mechanical lift calculated.
(2) The maximum combined mechanical and tire lift shall be no greater than the sum of the maximum mechanical lift and increased tire size calculated for the particular vehicle.
(3) Reconstructed motor vehicles shall be limited to the maximum combined lift allowed for the particular chassis used, in accordance with the applicable provisions of 540 CMR 6.05 (1) and (2), i.e. a vehicle having a 65" track, 105" wheel base, and an original manufacturer's door height of 21" is allowed a maximum combined lift of four inches above the original manufacturer's door height. Accordingly, the lower edge of the door, door edge line or floor panel, as stipulated in the general requirements of 540 CMR 6.00, of any unladen body mounted on such chassis may not exceed 25" above the level surface upon which the vehicle rests.
(4) In doubtful cases, or in any case where the original manufacturer's specified height is not known or available, or where a motor vehicle is assembled without using a particular body and/or chassis (i.e. homemade), the Registrar shall determine the allowable maximum height and may issue a permit authorizing the operation thereof.
(5) The Registrar shall periodically provide the specifications of the approved maximum altered heights.
6.06: Violations
(1) Due to the slight variances in production tolerances, violations must be in excess of one inch beyond the Registrar's specifications of approved maximum altered heights.
(2) The Registrar, in accordance with the provisions of M.G.L. c. 90, s22, shall suspend the registration of any motor vehicle equipped, altered or modified in violation of 540 CMR 6.00, and shall refuse to register any motor vehicle that the Registrar has reason to believe is equipped, altered or modified in violation of 540 CMR 6.00.
REGULATORY AUTHORITY
540 CMR 6.00: M.G.L. c.90, ss1, 7P and 31
540 CMR 6.00: ALTERATION OF MOTOR VEHICLE HEIGHT
Section
6.01: Purpose
6.02: Scope and Applicability
6.03: Definitions
6.04: General Requirements
6.05: Maximum Combined Mechanical and Tire Lift
6.06: Violations
6.01: Purpose
(1) The purpose of 540 CMR 6.00 is to provide rules and regulations for altering the height of four wheel drive motor vehicles by elevating or lowering the chassis or body more than two inches above or below the original manufacturer's height.
6.02: Scope and Applicability
(1) 540 CMR 6.00 is adopted by the Registrar of Motor Vehicles under the authority of M.G.L. c.90 s. 31 and pursuant to the provisions of M.G.L. c.90, s 7P to regulate alterations to the height of four wheel drive vehicles with an original manufacturer's gross vehicle weight rating of not over 10,000 operated on any way as defined in M.G.L. c. 90, s. 1.
6.03: Definitions
Four Wheel Drive Motor Vehicles: Any vehicle that is capable of providing torque to all four wheels.
Mechanical Lift: Modification to the chassis, suspension or body by any means exclusive of tires, rims, and load, affecting the height of four wheel drive motor vehicles.
Original Equipment: Any items of motor vehicle equipment, including tires, which are installed in or on a motor vehicle, or available by option for the particular vehicle from the original manufacturer at the time of its delivery to the first purchaser.
Original Manufacturer: Any person engaged in the manufacture or assembly of motor vehicles for delivery to the first purchaser.
Original Manufacturer's Height: The highest distance inclusive of the largest tires and highest suspension available as standard or optional equipment for the particular vehicle from the original manufacturer. The distance shall be measured between the lowest edge of the center line of the operator's door, or to the lowest point where the door would meet the body on vehicles without doors, or to the lowest point on the floor panel directly below the operator's position on vehicles designed without doors, and the level surface on which the unladen vehicle rests, as determined by the Registrar.
Reconstructed Motor Vehicle: Any four wheel drive motor vehicle constructed or ass3embled principally with used parts or components.
Wheel Base: The shortest distance between the center of the front and rear axles.
Wheel Track: The shortest distance between the centers of the tire treads on the same axle. On vehicles having different axle widths, the measurement shall be made on the widest one.
6.04: General Requirements
(1) No motor vehicle shall be altered or modified in any way that may cause the vehicle body or chassis to come in contact with the roadway, expose the fuel tank to damage from collision, or cause the tires to come in contact with the body, chassis, or steering components under normal operation. The horizontal plane, front to rear, shall not differ more than two inches.
(2) Alterations or modifications to the original braking, steering, or suspension system, which result in the impairment of the safe operation of the motor vehicle, are prohibited. All replacement parts and equipment used shall be designed and capable to perform the function or purpose for which it is intended and shall be equal or greater in strength and durability than the original parts provided by the original manufacturer.
(3) The wheel track may be increased by the use of tires and rims for a maximum total increase of four inches beyond the original manufacturer's specification. The use of spacers to increase the wheel track is prohibited. Fractions shall be excluded in all measurements and final calculations.
6.05 Maximum Combined Mechanical and Tire Lift
(1) The maximum mechanical lift for four wheel drive motor vehicles shall be calculated by multiplying the wheel base times the wheel track, and dividing the product by a safety factor of 2200:
i.e., 92" w/b x 58" w/t = 5336/2200 = 2" (maximum mechanical lift).
The outside diameter of the largest tire size available from the original manufacturer as standard or optional equipment for the particular motor vehicle may also be increased up to an amount equal to the maximum mechanical lift calculated.
(2) The maximum combined mechanical and tire lift shall be no greater than the sum of the maximum mechanical lift and increased tire size calculated for the particular vehicle.
(3) Reconstructed motor vehicles shall be limited to the maximum combined lift allowed for the particular chassis used, in accordance with the applicable provisions of 540 CMR 6.05 (1) and (2), i.e. a vehicle having a 65" track, 105" wheel base, and an original manufacturer's door height of 21" is allowed a maximum combined lift of four inches above the original manufacturer's door height. Accordingly, the lower edge of the door, door edge line or floor panel, as stipulated in the general requirements of 540 CMR 6.00, of any unladen body mounted on such chassis may not exceed 25" above the level surface upon which the vehicle rests.
(4) In doubtful cases, or in any case where the original manufacturer's specified height is not known or available, or where a motor vehicle is assembled without using a particular body and/or chassis (i.e. homemade), the Registrar shall determine the allowable maximum height and may issue a permit authorizing the operation thereof.
(5) The Registrar shall periodically provide the specifications of the approved maximum altered heights.
6.06: Violations
(1) Due to the slight variances in production tolerances, violations must be in excess of one inch beyond the Registrar's specifications of approved maximum altered heights.
(2) The Registrar, in accordance with the provisions of M.G.L. c. 90, s22, shall suspend the registration of any motor vehicle equipped, altered or modified in violation of 540 CMR 6.00, and shall refuse to register any motor vehicle that the Registrar has reason to believe is equipped, altered or modified in violation of 540 CMR 6.00.
REGULATORY AUTHORITY
540 CMR 6.00: M.G.L. c.90, ss1, 7P and 31
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
I read that as saying that the tire size related lift can be by the same amount as the mechanical lift...so if the mechanical lift can be 2", the tires can lift you by 2" as well.
The combined lift cannot be more than the sum of the two, or 4".
If you have a 116" WB, and a 61.9" track, that's 3.26" of lift.
So the mechanical lift limit for a 4 dr JK is 3.26".
As the tires can ALSO lift the JK 3.26", over the optional 32's....that's a 38.5" tire!
The COMBINED lift could therefore be 6.5"...AND, they can't fail you unless its over 7.5".
Of course, the mechanical lift is still limited to about 4" on a practical basis (An inch over the 3.26")...and you can't FIT 38's with a 4" lift anyway....maybe 37's.
The combined lift cannot be more than the sum of the two, or 4".
If you have a 116" WB, and a 61.9" track, that's 3.26" of lift.
So the mechanical lift limit for a 4 dr JK is 3.26".
As the tires can ALSO lift the JK 3.26", over the optional 32's....that's a 38.5" tire!
The COMBINED lift could therefore be 6.5"...AND, they can't fail you unless its over 7.5".
Of course, the mechanical lift is still limited to about 4" on a practical basis (An inch over the 3.26")...and you can't FIT 38's with a 4" lift anyway....maybe 37's.
JK Super Freak
Joined: Dec 2006
Posts: 1,422
Likes: 0
From: Montreal QC, Canada
FYI - The Toyo M-55s come in LT255/85R16 - that's 33.3" by 10.4". It's a 10 ply E load rated tire that's pinned for studs. The Canadian version isn't pinned for studs though - I had to drive down to the US to pick mine up. :-) I went with some LT285/75R16s to match my summer MTs, giving me the option of using 4-season chains in the future.
js.
js.
Thread Starter
JK Enthusiast
Joined: Sep 2006
Posts: 121
Likes: 1
Hmmm. Here's one...
Toyo Tire
LT285/75R17 Open Country MT.
Overall diameter is 34.1" and width is just under 11.5" Not super narrow, but better than many of the 12+" versions, and perfect at that elusive 34" mark.
Also approved for a 7.5" wide rim, so you could use it on the factory 17" and save some $$.
Static load is 15.8", so you'll get just over an inch more daylight under a Rubicon axle.
Construction details are similar to the BFG with 3 sidewall plies.
Here is the tread:
Toyo Tire
LT285/75R17 Open Country MT.
Overall diameter is 34.1" and width is just under 11.5" Not super narrow, but better than many of the 12+" versions, and perfect at that elusive 34" mark.
Also approved for a 7.5" wide rim, so you could use it on the factory 17" and save some $$.
Static load is 15.8", so you'll get just over an inch more daylight under a Rubicon axle.
Construction details are similar to the BFG with 3 sidewall plies.
Here is the tread:
JK Enthusiast
Joined: May 2007
Posts: 237
Likes: 1
From: Saint Paul, MN
Hmmm. Here's one...
Toyo Tire
LT285/75R17 Open Country MT.
Overall diameter is 34.1" and width is just under 11.5" Not super narrow, but better than many of the 12+" versions, and perfect at that elusive 34" mark.
Also approved for a 7.5" wide rim, so you could use it on the factory 17" and save some $$.
Static load is 15.8", so you'll get just over an inch more daylight under a Rubicon axle.
Construction details are similar to the BFG with 3 sidewall plies.
Here is the tread:
Toyo Tire
LT285/75R17 Open Country MT.
Overall diameter is 34.1" and width is just under 11.5" Not super narrow, but better than many of the 12+" versions, and perfect at that elusive 34" mark.
Also approved for a 7.5" wide rim, so you could use it on the factory 17" and save some $$.
Static load is 15.8", so you'll get just over an inch more daylight under a Rubicon axle.
Construction details are similar to the BFG with 3 sidewall plies.
Here is the tread:
TEEJ has really got my gears turning over the last week with his thoughts on this, and I must admit I am strarting to come to more his side of the table. My experience on the skinnier tires has always been on lighter vehicles, such as my FJ-40, and others. The weight of the vehicle was not in the forefront of my mind, and I took for granted how much different this unlimited is to my previous off roaders. With the weight of my unlimited, I'm thinking that being closer to 10.5 inches wide just won't be enough. I'm still not wanting to be at 12.5 though, so these Toyo's seem like a great size. Just wish Toyo's weren't so stinking expensive!