best 2.5" lift for less than $1000

wayoflife

wayoflife

Administrator
Staff member
cody0707 said:
Took a step away from this thread for awhile and came back and reread it. I am with these two guys who I quoted. I had no idea and I do apologize Eddie. So now that I realized I am ignorant to tire size I guess I need to get that squared away before I worry about lift size.

I had thought a 315/70R17 was equivelent to a 35x12.50. Am I correct in that you are saying a 315/70R17 is actually equal to a 37x12.50? If This isn't correct I am going to have to ask if you would please dumb it down for me. Here is my new interpretation of what I think you are telling me:

315/70R17 = 37x12.50
305/70R17 = 35x12.50???
285/70R17 = 34x??

And so on?

I think this gets confusing due to tire calculators telling you what the actual metric tire measures out to and the standard 33x12.50 has been read that the tire is a 33" tall tire instead of being a actual 32.

I think I'm starting to confuse myself.
Click to expand...

:cheesy: It's all good my friend and yes, I think you are finally getting it. When you convert a metric tire into inches, you are getting the actual size in inches. You need to take this actual size and compare it to its equivalent advertised inch tire to know what will work with what lift. If you have a metric tire that your calculator says it has an actual size of 35", you are going to want a lift that will accommodate an advertised 37" tire as it will have an actual size of 35".

Where it gets confusing is in the ratio, particularly the 2nd number as that is a percent measurement. For instance, a 255/75R17 means that you have a tread width of 255mm and then the sidewall height is 75% of that. In other words, depending on what wheel size you are running and what percent is stated (70 or a 75), that will change the ultimate tire size height. Also, 255 is only about 10" wide, 285 is about 11", a 305 is about 12 and a 315 is about 12.50". :crazyeyes:

Having said that, here is a general list of metric to equivalent advertised inch size tires:

315/75R17 = +/- 37x12.50
305/70R17 = +/- 35x12.00
285/75R17 = +/- 35x11.00
265/70R17 = +/- 33x10.50
255/75R17 = +/- 32x10.00

Again, figuring out metric tires is a ratio so these are close approximations based on ACTUAL measurement that I have done over the years. I hope that makes sense.
 
M

MarkW13

New member
cody0707 said:
Took a step away from this thread for awhile and came back and reread it. I am with these two guys who I quoted. I had no idea and I do apologize Eddie. So now that I realized I am ignorant to tire size I guess I need to get that squared away before I worry about lift size.

I had thought a 315/70R17 was equivelent to a 35x12.50. Am I correct in that you are saying a 315/70R17 is actually equal to a 37x12.50? If This isn't correct I am going to have to ask if you would please dumb it down for me. Here is my new interpretation of what I think you are telling me:

315/70R17 = 37x12.50
305/70R17 = 35x12.50???
285/70R17 = 34x??

And so on?

To where my inturpritation was:

315/70R17 = 35x12.50
305/70R17 = 34x12.50
285/70R17 = 33x12

I think this gets confusing due to tire calculators telling you what the actual metric tire measures out to and the standard 33x12.50 has been read that the tire is a 33" tall tire instead of being a actual 32.

I think I'm starting to confuse myself.
Click to expand...

I'm not sure I want to enter the tire size debate, but here I go.

I have been looking at manufacturers tire sizes not as marked or as mounted and measured, but as the diameter they say is measured. Most 35's measured from the manufacturer are stating 35.2 to 34.6. 315's are consistently showing 34.8.

As I understand a 35, 35.2, 34.8 will all lose actual measured height when mounted and loaded with the weight of your jeep given air pressure is in a normal road operating range the tape measure will show from ground to tread edge about 33.5 ish.

I expect that the same 35 will be even shorter at trail pressure (10-12 psi) probably dropping an additional inch or more. That being said an advertised 37 is really probably no more than 34" from ground to tread edge at trail pressure.

Is this correct, or am I in left field?
 
RMC2

RMC2

Caught the Bug
OP, If you are trying to do this all on a budget, you may want to consider the smaller end of the tire spectrum and a true 2" lift. Something that also matches your existing gears. 2dr look ok on a smaller tire more than a 4dr anyway (imo). I did not say better, but ok. If you are really trail riding, you will not need so much in a lift or tire.
 
C

cody0707

New member
wayoflife said:
:cheesy: It's all good my friend and yes, I think you are finally getting it. When you convert a metric tire into inches, you are getting the actual size in inches. You need to take this actual size and compare it to its equivalent advertised inch tire to know what will work with what lift. If you have a metric tire that your calculator says it has an actual size of 35", you are going to want a lift that will accommodate an advertised 37" tire as it will have an actual size of 35".

Where it gets confusing is in the ratio, particularly the 2nd number as that is a percent measurement. For instance, a 255/75R17 means that you have a tread width of 255mm and then the sidewall height is 75% of that. In other words, depending on what wheel size you are running and what percent is stated (70 or a 75), that will change the ultimate tire size height. Also, 255 is only about 10" wide, 285 is about 11", a 305 is about 12 and a 315 is about 12.50". :crazyeyes:

Having said that, here is a general list of metric to equivalent advertised inch size tires:


315/75R17 = +/- 37x12.50
305/70R17 = +/- 35x12.00
285/75R17 = +/- 35x11.00
265/70R17 = +/- 33x10.50
255/75R17 = +/- 32x10.00

Again, figuring out metric tires is a ratio so these are close approximations based on ACTUAL measurement that I have done over the years. I hope that makes sense.
Click to expand...

Thanks for dumbing this down for me even more so than what you have before. I am back at the drawing board now. What would be the max size tire you would recommend with a 2.5" lift assuming the lift actually netted between 2.5" and 3" and running a D30 that has been sleeved and gusseted?

My jeep is geared for 4.56s and has the 3.6. Going by the tire chart it says I am optimally geared for a 35" tire. Is this chart based off of a true 35" or an advertised? Since I already have the gears done I think it would probably be wise to build the jeep to match the gears at this point. Thoughts?
 
Last edited:
wayoflife

wayoflife

Administrator
Staff member
MarkW13 said:
I'm not sure I want to enter the tire size debate, but here I go.

I have been looking at manufacturers tire sizes not as marked or as mounted and measured, but as the diameter they say is measured. Most 35's measured from the manufacturer are stating 35.2 to 34.6. 315's are consistently showing 34.8.

As I understand a 35, 35.2, 34.8 will all lose actual measured height when mounted and loaded with the weight of your jeep given air pressure is in a normal road operating range the tape measure will show from ground to tread edge about 33.5 ish.

I expect that the same 35 will be even shorter at trail pressure (10-12 psi) probably dropping an additional inch or more. That being said an advertised 37 is really probably no more than 34" from ground to tread edge at trail pressure.

Is this correct, or am I in left field?
Click to expand...

You would literally have to take a tire that is NOT mounted on your Jeep, inflate it to its highest possible safe psi and then measure the diameter from the highest crowned point in the center of the tread to the opposite highest crowned point on the other to get a measurement that is remotely close to what is stated on the sidewall. Of course, if you measure a tire from edge to edge (the point where the sidewall makes a 90° turn to become the tread), you will get an accurate reading of what the diameter really is and for the most part, it'll be about 2" shorter that what is stated. Having said that, it doesn't matter what the actual measurement is or at least, not when it comes to lifts. The only thing that matters is that lift kits are designed to clear a specific size tire and that size is referring to what is listed on the side wall. A 2.5" lift will clear an advertised 35" tire meaning, it will clear a tire that has an actual measurement of 33". A 285/75R17 or 305/70R17 will be a similar fit as both will have an actual height of about 33" tall. Does that make sense?
 
Warebear

Warebear

New member
cody0707 said:
I am in the planning stage for phase 2 of my Jeep and plan on adding a 2.5" lift to my 2 door sport. I have managed to keep my Jeep as possible and hope to continue doing so. Most of the trails I run here in N. FL do not require me to disconnect the swaybar so i dont need max flex. I am looking for a soft ride. my jeep is my DD and only see trails about once or twice a month.

My budget for a 2.5" is $1,000.
Click to expand...

Based on this, with not much trail action going on and a d30, man I'd stay with 265/70R16 = +/- 33x10.50. Then you won't loose too much power, if any, with the stock gears?
 
RMC2

RMC2

Caught the Bug
MarkW13 said:
I'm not sure I want to enter the tire size debate, but here I go.

I have been looking at manufacturers tire sizes not as marked or as mounted and measured, but as the diameter they say is measured. Most 35's measured from the manufacturer are stating 35.2 to 34.6. 315's are consistently showing 34.8.

As I understand a 35, 35.2, 34.8 will all lose actual measured height when mounted and loaded with the weight of your jeep given air pressure is in a normal road operating range the tape measure will show from ground to tread edge about 33.5 ish.

I expect that the same 35 will be even shorter at trail pressure (10-12 psi) probably dropping an additional inch or more. That being said an advertised 37 is really probably no more than 34" from ground to tread edge at trail pressure.

Is this correct, or am I in left field?
Click to expand...

No wonder I was confused on all of this. I was using what the manufacturer stated for true sizes (although I know tire pressure acounts for some of that). Oops missed Eddie's response.
 
MR.Ty

MR.Ty

Token East Coast Guy
Well all this info was enlightening. I do have one more question and i must warn you that it is silly. Say you have the same manufacturer making a 35/12.50r17 and a 305/70/17. Once mounted on a vehicle, which one ends up being bigger on average?
 
wayoflife

wayoflife

Administrator
Staff member
cody0707 said:
Thanks for dumbing this down for me even more so than what you have before. I am back at the drawing board now. What would be the max size tire you would recommend with a 2.5" lift assuming the lift actually netted between 2.5" and 3" and running a D30 that has been sleeved and gusseted?

My jeep is geared for 4.56s and has the 3.6. Going by the tire chart it says I am optimally geared for a 35" tire. Is this chart based off of a true 35" or an advertised? Since I already have the gears done I think it would probably be wise to build the jeep to match the gears at this point. Thoughts?
Click to expand...

I would recommend that you look at an advertised 35" tire and no bigger. The metric equivalent for this would be a 285/75R17 or a 305/70R17 or there about. Your 4.56 gears will be perfect for a set of advertised 35" tires. Again, the only time you need to concern yourself with "actual" tire size is when you are calibrating your speedometer.

With a set of advertised 35" tires that have an actual measurement of 33", you can safely run it with a 2.5" coil spacer lift and shock extensions for what it's worth. If it were me, this is what I would do as it can be done for less than $1000, won't require you to install a new front drive shaft and will retain the ride you have now. The PROBLEM with running a 2.5" coil lift is that MOST of them will yield way more than 3" of lift especially on a 2-door. At that height, you will have to address the issues that come with the extra height.
 
wayoflife

wayoflife

Administrator
Staff member
MR.Ty said:
Well all this info was enlightening. I do have one more question and i must warn you that it is silly. Say you have the same manufacturer making a 35/12.50r17 and a 305/70/17. Once mounted on a vehicle, which one ends up being bigger on average?
Click to expand...

35x12.50 will be a wider tire. The 305/70R17 may be a bit taller but will also be narrower.
 
JKWrang

JKWrang

New member
[ 315] / [75] R [16] = [*(Tire Width x Aspect Ratio x 2) / 2550 + Wheel Diameter*] x [*Tire Width / 25.4*] - [*Wheel Diameter] = [35] x [12.4] - [16]

This is whats on my Jeep. Measures in at around 33.5"

Just in case anyone was still confused.
 
jeeeep

jeeeep

Hooked
and now another thing to add to bag of "what????" some manufacturers offer the same tire in different load ratings and speed ratings which also changes the overall tire size. Also the wheel will affect it as well, it's marginal changes but the point is to not get too hung up on actual size and just refer to the stated size when choosing a lift.

As was mentioned earlier, if you go with a 3" coil lift you should be able to fit any tire 37 and below under just fine, of course as you get closer to the 37 it'll require some trimming.

I have a 3.5" lift running BFG 315's, plenty of clearance without rubbing when wheeling, I thought about trimming or putting on the flat fenders but with 315's IMO it'll have too much space in the wheel well and look like a roller skate.

I'll be changing to the new KO2 37" and plan to do something with the fenders, trim a little and replace the rear driveshaft...arghhhh my brain is also liking the idea of a Trail 60 but that's another thread lol

BTW, my tire spec size is 34.4" once mounted and measured for speedo calibration, they measured out at about 33
 
Last edited:
RMC2

RMC2

Caught the Bug
Warebear said:
Ha I have copied and pasted half of this thread into my notepad for future reference. Tires are stupid.
Click to expand...

I hope i didn't make your cut and post. :doh:

Now I am going to have to measure the 285/75/16 on my truck when I get to Oklahoma next week(that is where my truck and CJ7 are at) :gaah:
 
C

cody0707

New member
wayoflife said:
I would recommend that you look at an advertised 35" tire and no bigger. The metric equivalent for this would be a 285/75R17 or a 305/70R17 or there about. Your 4.56 gears will be perfect for a set of advertised 35" tires. Again, the only time you need to concern yourself with "actual" tire size is when you are calibrating your speedometer.

With a set of advertised 35" tires that have an actual measurement of 33", you can safely run it with a 2.5" coil spacer lift and shock extensions for what it's worth. If it were me, this is what I would do as it can be done for less than $1000, won't require you to install a new front drive shaft and will retain the ride you have now. The PROBLEM with running a 2.5" coil lift is that MOST of them will yield way more than 3" of lift especially on a 2-door. At that height, you will have to address the issues that come with the extra height.
Click to expand...


This is really confusing still. I currently have 285/75R16 Treadwright Guard dogs on my Jeep now. The only thing I have on my Jeep to aid in clearing the tires are a set of 19/59 factory springs and Rubicon takeoff shocks. The tires do not rub at all even if I disconnect my swaybar and flex it as much as possible, granted I do have flat fenders. This is what also gave me the impression I could clear 315/75R16 tires with a small lift. I know the stiffer springs gave me a small lift but I don't believe it is what a actual 2.5" lift will give me although I could be wrong. So with flat fenders and a 2.5" lift I am still incorrect in assuming I could fit 315/75R16 which according to a poster above would only measure around 1 inch larger than what I have now?

Also with the 285/75R16 tires I have. They measure 32.75 installed and actually measured using radius/3.14 and is accurate according to my GPS and a police calibrated radar (wasn't speeding, I'm a law enforcement officer and had access to one). At 70 MPH my Jeep is running right around 2650 RPMs.
 
wayoflife

wayoflife

Administrator
Staff member
cody0707 said:
This is really confusing still. I currently have 285/75R16 Treadwright Guard dogs on my Jeep now. The only thing I have on my Jeep to aid in clearing the tires are a set of 19/59 factory springs and Rubicon takeoff shocks. The tires do not rub at all even if I disconnect my swaybar and flex it as much as possible, granted I do have flat fenders.
Click to expand...

That's because you are running trimmed fenders - a point that you failed to mentioned until now.

This is what also gave me the impression I could clear 315/75R16 tires with a small lift. I know the stiffer springs gave me a small lift but I don't believe it is what a actual 2.5" lift will give me although I could be wrong. So with flat fenders and a 2.5" lift I am still incorrect in assuming I could fit 315/75R16 which according to a poster above would only measure around 1 inch larger than what I have now?
Click to expand...

With flat fenders, a 2.5" lift and appropriate bump stop extensions yes, you could probably run 315's. You'll most likely see some rubbing at a full flex but, I doubt you'll get too many opportunities to do that where you live.

Also with the 285/75R16 tires I have. They measure 32.75 installed and actually measured using radius/3.14 and is accurate according to my GPS and a police calibrated radar (wasn't speeding, I'm a law enforcement officer and had access to one). At 70 MPH my Jeep is running right around 2650 RPMs.
Click to expand...

Ummm, are we already forgetting what we've already covered here? 32.75" is almost 33" as in, what an advertised 35" will measure :rolleyes2:
 
C

cody0707

New member
wayoflife said:
That's because you are running trimmed fenders - a point that you failed to mentioned until now.



With flat fenders, a 2.5" lift and appropriate bump stop extensions yes, you could probably run 315's. You'll most likely see some rubbing at a full flex but, I doubt you'll get too many opportunities to do that where you live.



Ummm, are we already forgetting what we've already covered here? 32.75" is almost 33" as in, what an advertised 35" will measure :rolleyes2:
Click to expand...

I mentioned flat fenders in post 4 but you were trying to get me to realize my error in tire size. Ok so that clears up a lot of confusion. And yup the 32.75 comment pretty much proves your point. Thanks for the help. I think I am finally tracking what you are saying.
 
JKWrang

JKWrang

New member
wayoflife said:
Having said that, here is a general list of metric to equivalent advertised inch size tires:

315/75R17 = +/- 37x12.50
305/70R17 = +/- 35x12.00
285/75R17 = +/- 35x11.00
265/70R17 = +/- 33x10.50
255/75R17 = +/- 32x10.00.
Click to expand...

Okay so im a little confused. I have a 2.5" Teraflex coil lift with 315/75r16 Mud Grapplers and uncut stock fenders. No rub at flex.

Am i missing something? Im DEFINITELY not running 37s. I have 35s (as stated - measuring 33.5 mounted under my 4 door).

I know I have 35s because NoRoads 37" Terragrapplers are visibly larger than my tires side by side. Youngfire's 35" Terrgrapplers look the same as mine in height side by side.

According to the above posts my information is inaccurate. What am I missing?
 
You must log in or register to reply here.
Top Bottom