2.5" Level Kit, What Size Rear Blocks?
Senior Member
Joined: Mar 2014
Posts: 1,813
Likes: 489
From: Louisiana
Be careful ... going from a 2" to a 2.5" spacer doesn't necessarily mean you'll only gain 1/2" in the front. The way our suspensions are, the "lift" is controlled by how much the added spacer height affects the UCA - causing it to pivot down - which is what's directly controlling the amount of lift. That's why the 1.5" kits are generally about a 1.2" or 1.25" spacer ...
the "better" kit MFG's have researched, tested and KNOW pretty much exactly how thick to make each spacer to give you the RESULTING 1.5, 2 or 2.5" of lift in the front. I can only guess that some don't care as much, and just offer spacers in preset sizes, and once installed you just "get what you get".
as for the rear, that's a different story. Because it's leaf springs, and you're simply adding space between the bottom of the springs and the top of the rear axle, then it's a pretty linear deal. If you install a front kit, and see that you need 1" higher in the back ... just measure your existing blocks, and get some that are 1" taller ...
the "better" kit MFG's have researched, tested and KNOW pretty much exactly how thick to make each spacer to give you the RESULTING 1.5, 2 or 2.5" of lift in the front. I can only guess that some don't care as much, and just offer spacers in preset sizes, and once installed you just "get what you get".
as for the rear, that's a different story. Because it's leaf springs, and you're simply adding space between the bottom of the springs and the top of the rear axle, then it's a pretty linear deal. If you install a front kit, and see that you need 1" higher in the back ... just measure your existing blocks, and get some that are 1" taller ...
Thread Starter
US ARMY
Joined: May 2015
Posts: 245
Likes: 12
Be careful ... going from a 2" to a 2.5" spacer doesn't necessarily mean you'll only gain 1/2" in the front. The way our suspensions are, the "lift" is controlled by how much the added spacer height affects the UCA - causing it to pivot down - which is what's directly controlling the amount of lift. That's why the 1.5" kits are generally about a 1.2" or 1.25" spacer ...
the "better" kit MFG's have researched, tested and KNOW pretty much exactly how thick to make each spacer to give you the RESULTING 1.5, 2 or 2.5" of lift in the front. I can only guess that some don't care as much, and just offer spacers in preset sizes, and once installed you just "get what you get".
as for the rear, that's a different story. Because it's leaf springs, and you're simply adding space between the bottom of the springs and the top of the rear axle, then it's a pretty linear deal. If you install a front kit, and see that you need 1" higher in the back ... just measure your existing blocks, and get some that are 1" taller ...
the "better" kit MFG's have researched, tested and KNOW pretty much exactly how thick to make each spacer to give you the RESULTING 1.5, 2 or 2.5" of lift in the front. I can only guess that some don't care as much, and just offer spacers in preset sizes, and once installed you just "get what you get".
as for the rear, that's a different story. Because it's leaf springs, and you're simply adding space between the bottom of the springs and the top of the rear axle, then it's a pretty linear deal. If you install a front kit, and see that you need 1" higher in the back ... just measure your existing blocks, and get some that are 1" taller ...
5 Year Member
Joined: Oct 2008
Posts: 8,279
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From: Lockport, Louisiana
How close to the upper control arm on the inside? They may rub on the lower wheelwells when turning hard going in reverse up an incline...my 35's rubbed on my '04 Lariat in that spot. The side lugs may be rubbing if you have mud terrains...anytime you run 35x12's problems may develop with just a leveling kit.
Senior Member
Joined: Mar 2014
Posts: 1,813
Likes: 489
From: Louisiana
2.5" Level Kit, What Size Rear Blocks?
How close to the upper control arm on the inside? They may rub on the lower wheelwells when turning hard going in reverse up an incline...my 35's rubbed on my '04 Lariat in that spot. The side lugs may be rubbing if you have mud terrains...anytime you run 35x12's problems may develop with just a leveling kit.
If you go 35x12.50 you'll need spacers or aftermarket wheels with less offset to keep them off the control arms ... and you will need to do some trimming and/or bending to keep the tires off the bottom edges of the wheel wells.
Senior Member
Joined: Mar 2014
Posts: 1,813
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From: Louisiana
Ok ... just in the interest of more info ... Here's my 2014 FX4 ... 1.5" kit up front w/ 2" rear blocks ... 295/60r20 MT's on factory 20's (which are a +44mm offset). Here's what you get w/ that combo:
and, here's how close the tires are to the UCA's:
As you can see, there's less than 1/2" between my tires and UCA's, and that's with an 11.8" wide tire ... think about that w/ a 12.50" wide tire (and the fact that a LOT of the 12.50's are wider than 12.50 ... I think Nitto Trail Grapplers are close to 13" or more at their widest points)
So, if you are really wanting 35x12.50x20's, then going w/ a little more lift w/ help a LITTLE with clearances within the wheel well ... but not with the UCA's ... you WILL need either spacers or wheels w/ less offset (more like a +12) ... Trust me. I have a great tire guy, and he let me try out some Mastercraft MXT 35x12.50x20's on my truck first ... they rubbed the UCA's as soon as you turned the steering wheel. I put them on with my 1.25" spacers, and the were off the UCA's, but were then rubbing on the front/back of the wheel wells. I could have trimmed that up to resolve it, but they would have been stuffed so tight in there that any real articulation of the suspension would have been causing tires to rub on wheel wells - side and top... which also brings me to the fact that the 35x12.50's would have protruded a decent amount outside my fenders, which means upward articulation would cause the tire to slam into the fender - NOT good ... AND ... you'd really want some extended flares to keep rocks and crud from flying off your tires and all over the sides of your truck.
I guess that's the long way of saying that 295/60's are truly a perfect tire for our trucks with just about a 2" level ... but that's up to you to decide. It's your truck, and you need to set it up however makes you happy.
and, here's how close the tires are to the UCA's:
As you can see, there's less than 1/2" between my tires and UCA's, and that's with an 11.8" wide tire ... think about that w/ a 12.50" wide tire (and the fact that a LOT of the 12.50's are wider than 12.50 ... I think Nitto Trail Grapplers are close to 13" or more at their widest points)
So, if you are really wanting 35x12.50x20's, then going w/ a little more lift w/ help a LITTLE with clearances within the wheel well ... but not with the UCA's ... you WILL need either spacers or wheels w/ less offset (more like a +12) ... Trust me. I have a great tire guy, and he let me try out some Mastercraft MXT 35x12.50x20's on my truck first ... they rubbed the UCA's as soon as you turned the steering wheel. I put them on with my 1.25" spacers, and the were off the UCA's, but were then rubbing on the front/back of the wheel wells. I could have trimmed that up to resolve it, but they would have been stuffed so tight in there that any real articulation of the suspension would have been causing tires to rub on wheel wells - side and top... which also brings me to the fact that the 35x12.50's would have protruded a decent amount outside my fenders, which means upward articulation would cause the tire to slam into the fender - NOT good ... AND ... you'd really want some extended flares to keep rocks and crud from flying off your tires and all over the sides of your truck.
I guess that's the long way of saying that 295/60's are truly a perfect tire for our trucks with just about a 2" level ... but that's up to you to decide. It's your truck, and you need to set it up however makes you happy.
Thread Starter
US ARMY
Joined: May 2015
Posts: 245
Likes: 12
Ok ... just in the interest of more info ... Here's my 2014 FX4 ... 1.5" kit up front w/ 2" rear blocks ... 295/60r20 MT's on factory 20's (which are a +44mm offset). Here's what you get w/ that combo:
and, here's how close the tires are to the UCA's:
As you can see, there's less than 1/2" between my tires and UCA's, and that's with an 11.8" wide tire ... think about that w/ a 12.50" wide tire (and the fact that a LOT of the 12.50's are wider than 12.50 ... I think Nitto Trail Grapplers are close to 13" or more at their widest points)
So, if you are really wanting 35x12.50x20's, then going w/ a little more lift w/ help a LITTLE with clearances within the wheel well ... but not with the UCA's ... you WILL need either spacers or wheels w/ less offset (more like a +12) ... Trust me. I have a great tire guy, and he let me try out some Mastercraft MXT 35x12.50x20's on my truck first ... they rubbed the UCA's as soon as you turned the steering wheel. I put them on with my 1.25" spacers, and the were off the UCA's, but were then rubbing on the front/back of the wheel wells. I could have trimmed that up to resolve it, but they would have been stuffed so tight in there that any real articulation of the suspension would have been causing tires to rub on wheel wells - side and top... which also brings me to the fact that the 35x12.50's would have protruded a decent amount outside my fenders, which means upward articulation would cause the tire to slam into the fender - NOT good ... AND ... you'd really want some extended flares to keep rocks and crud from flying off your tires and all over the sides of your truck.
I guess that's the long way of saying that 295/60's are truly a perfect tire for our trucks with just about a 2" level ... but that's up to you to decide. It's your truck, and you need to set it up however makes you happy.
and, here's how close the tires are to the UCA's:
As you can see, there's less than 1/2" between my tires and UCA's, and that's with an 11.8" wide tire ... think about that w/ a 12.50" wide tire (and the fact that a LOT of the 12.50's are wider than 12.50 ... I think Nitto Trail Grapplers are close to 13" or more at their widest points)
So, if you are really wanting 35x12.50x20's, then going w/ a little more lift w/ help a LITTLE with clearances within the wheel well ... but not with the UCA's ... you WILL need either spacers or wheels w/ less offset (more like a +12) ... Trust me. I have a great tire guy, and he let me try out some Mastercraft MXT 35x12.50x20's on my truck first ... they rubbed the UCA's as soon as you turned the steering wheel. I put them on with my 1.25" spacers, and the were off the UCA's, but were then rubbing on the front/back of the wheel wells. I could have trimmed that up to resolve it, but they would have been stuffed so tight in there that any real articulation of the suspension would have been causing tires to rub on wheel wells - side and top... which also brings me to the fact that the 35x12.50's would have protruded a decent amount outside my fenders, which means upward articulation would cause the tire to slam into the fender - NOT good ... AND ... you'd really want some extended flares to keep rocks and crud from flying off your tires and all over the sides of your truck.
I guess that's the long way of saying that 295/60's are truly a perfect tire for our trucks with just about a 2" level ... but that's up to you to decide. It's your truck, and you need to set it up however makes you happy.