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Discussion Starter #1
Hey all,

When looking at a stock 2D JK rubicon sitting next to a stock TJ rubicon it appears as though the ground clearance to the frame rails and to the transfer case skid was less on the JK, is this true or are my eyes deceiving me? I have seen some images floating around the interwebs that compare angles but none seem to give hard measurements from the ground. Ground clearance specs. that I could find only give numbers for "Min. ground clearance" which would be to the differential housing.

Does anyone have any actual measurements taken on level ground for clearance from the ground to a frame rail and ground to the transfer case skid for both a stock JK and a stock TJ preferrably with the same sized tires?

Thanks,
Shawn
 

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Found these online. Referrence from Rockcrawler.com











JK

Clearances P225/75R16 P245/75R16 P255/75R17 P255/70R18 LT255/75R17
Approach Angle Degree 40.8 42.0 43.8 44.6 44.3
Breakover Angle Degree 21.8 23.1 24.9 25.5 25.4
Departure Angle Degree 37.4 38.7 40.3 40.6 40.4
Front Axle to Ground (inches) 9.1 9.6 10.3 10.6 10.5
Rear Axle to Ground (inches) 8.8 9.4 10.1 10.3 10.2


TJ:

Wheelbase = 93.4"
Overall length = 155.4"
Overall width = 66.7"
Overall height (soft top) = 70.8"
Track width = 57.8 - 58.5"
Turning diameter = 33.5'-36'
Curb weight = 3,092-3,832 lbs

Cargo capacity = 55.7 cu ft.
Fuel capacity = 15 - 19 gal (19 gal became standard during the 99 model year)
Towing capacity = 1,000 lbs 4cyl / 2,000 lbs 6 cyl

Ground clearance (at axle) = 8.7"-9.2" front / 8.6"-9.1" rear

Approach angle = 42.2*
Departure angle = 31.5*
Breakover angle = 22.3*
 

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Discussion Starter #3
@Rics1997 - Thanks for the reply but I have already seen this and it was what I was referring to in the original post. All this tells you is approach, departure, breakover angle and distance from the ground to the differential housing.

I want a distance measurement from the ground to the bottom of a frame rail or to the bottom of the transfer case skid on a TJ and JK
 

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I don't think you can really call what you're talking about as "ground clearance"... It's just more of the distance from a fixed point to the ground.

If its really relevant, just go to a jeep dealer with a tape and measure it. It would be easy enough to do so. :)
 

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Discussion Starter #5
The very definition of ground clearance is the amount of distance from the ground to the vehicles chassis. In this case I don't really care about the distance to the bottom of the differential housing which is normally reported for the ground clearance value but rather the frame and more specifically the transfer case skid because on the JK it seems to be quite low and more vulnerable to trail damage and hanging the vehicle up when "breaking over" an obstacle as compared to a TJ or YJ or CJ for that matter.

Basically does the frame on a JK sit lower than the heritage models TJ, YJ, CJ in stock trim?
 

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The breakover angles have nothing to do with the differentials, but where you are going to hit on the belly of the Jeep when you are breaking over a hill. The better the angle the higher the slope you can make without scraping under your Jeep.

The differential is only taken into consideration for the axle to ground clearances.
 

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Discussion Starter #10
@Joe - You are restating the obvious...I never said breakover angles had anything to do with the differential housing. What I did say is that the value typically reported by manufacturers for vehicle ground clearance is the distance from the ground to the bottom of the differential housing because that is typically the minimum clearance value.

When I was talking about "breaking over" an obstacle I meant something like a rock not a hill....for example if the frame rails are located lower relative to the axles then by crawling over a rock you have a better chance of smacking the rock with your frame when your wheel comes down off of it and the same with the transfer case.

Obviously I am aware that the breakover angle combined with the belly clearance contributes to how "steep" of a hill you can drive over without getting hung up, but I am more concerned with the height of obstacles I can drive over without hitting my chassis.

Can anyone here provide me these distance measurements?

Thanks,
Shawn
 

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Hey all,

When looking at a stock 2D JK rubicon sitting next to a stock TJ rubicon it appears as though the ground clearance to the frame rails and to the transfer case skid was less on the JK, is this true or are my eyes deceiving me? I have seen some images floating around the interwebs that compare angles but none seem to give hard measurements from the ground. Ground clearance specs. that I could find only give numbers for "Min. ground clearance" which would be to the differential housing.

Does anyone have any actual measurements taken on level ground for clearance from the ground to a frame rail and ground to the transfer case skid for both a stock JK and a stock TJ preferrably with the same sized tires?

Thanks,
Shawn
It's most likely that your eyes are indeed deceiving you. You can't compare a "stock" JK and a "stock" TJ with the "same sized tires" because stock TJ's have smaller tires than stock JK's. Let's try some logic. JK and TJ Rubicons both have D44 axles. The JK has more clearance under the differential. That tells me the frame rails on the JK will not have less clearance, especially with 1/2" more tire clearance (32" vs. 31").
 

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It's most likely that your eyes are indeed deceiving you. You can't compare a "stock" JK and a "stock" TJ with the "same sized tires" because stock TJ's have smaller tires than stock JK's. Let's try some logic. JK and TJ Rubicons both have D44 axles. The JK has more clearance under the differential. That tells me the frame rails on the JK will not have less clearance, especially with 1/2" more tire clearance (32" vs. 31").
Logic does not belong in this thread. :rolleyes:
 

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It's most likely that your eyes are indeed deceiving you. You can't compare a "stock" JK and a "stock" TJ with the "same sized tires" because stock TJ's have smaller tires than stock JK's. Let's try some logic. JK and TJ Rubicons both have D44 axles. The JK has more clearance under the differential. That tells me the frame rails on the JK will not have less clearance, especially with 1/2" more tire clearance (32" vs. 31").
I think your conclusion is probably right, but I don't know about that logic. The frame rails can drop down pretty far, look at a GM HD truck and compare to a Ford or Dodge. That is a function of the IFS, of course, but I think it illustrates the general point that frame rail height is not *necessarily* proportional to diff clearance.
 

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Discussion Starter #15
@ daggo - The clearance under the differential housing is a function of the tire diameter and the diameter of the housing itself. It has NOTHING to do with the relationship of the frame to the ground which is what I am talking about.

The axles as long as the tires are touching the ground have an obvious fixed distance from it based on the parameters I mentioned but the relationship of the frame to the ground is based on the length of the suspension springs. If you have a longer or shorter spring you will either move the frame further or closer to the ground respectively. Its the whole premise behind the idea of a "lift kit" as we are all so familiar with.

The JK is able to fit bigger tires under it in stock configuration because the shape of the body is different from the TJ....it is slightly taller with bigger wheel well openings...this fact has nothing to do with the relative position of the frame. In fact the manufacturers have used this "illusion" on many vehicles to give them the appearance of clearance when in fact they had actually lowered the frame with respect to the axles to give a lower center of gravity and better on road characteristics...take the new gen Ford F150 for example as compared to older ones. There is not as much frame clearance but it looks really tall due to the fact that the body was made higher and the "beltline" raised.

Since I can't seem to get measurements I am not sure whether or not the frame is actually lower with respect to the axles although from a glance this is what it seems like. I suspect that what happened was that the JK frame was made lower for twofold reasons...One of which to lower the angle of the control arms (the slightly longer wheelbase also helped with this) and the other to lower the center of gravity both of which gives it the better onroad handling characteristics along with the wider track.

The new body (and frame but the general shape didnt change much) which allowed for fitment of bigger tires (32" vs. 31") increased the "reported" min. clearance value to 10" or whatever it is but that doesnt tell the whole story because the fact is if I am going over most obstacles like a large rock or a log I will put my tire on the obstacle and the 10" min clearance wont come into play because as long as the tire is in contact with the rock/log (assuming its relatively evenly shaped and near the edge of the rock) the 10" will be maintained from it (This is obviously not the case with driving down a rutted trail where the axles will actually get hung up first). Now when I drop off that rock lets say from my pass. side tire the distance from the frame to the ground will come into play as to whether or not I will impact the frame rail or not.

So even though you might have gained .5" clearance from the 32" tire vs. the 31" tire the "belly" of the jeep might be lower and thats my concern.

I know that rubi tires are different sizes from JK to TJ...if someone can provide frame/skid measurements then its easy enough to take into account the different tire sizes (basically subtract .5" from the JK to get the same measurement on the TJ).

But again this doesnt have to be limited to rubicons....it could be X, Sport, Sahara whatever.

Thanks,
Shawn
 

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RedRubi2012 said:
if someone can provide frame/skid measurements
Why can't you just go to a dealership and measure it yourself? Or maybe call Chrysler and ask them?

It's pretty obvious by now that actually just doing that is probably the best way to get the answer you seek...

Happy measuring!! :rofl:
 

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Discussion Starter #17
Because I dont have a dealership very near to me and furthermore there is no good way to approach the situation. I would probably at the least get some odd looks at the dealership or possibly get asked to leave if I wasn't looking to buy something.

I thought about going down there at night but that might be worse...what if someone saw me creeping around a Jeep at night? They may figure I am trying to sabatage the thing, or steal something from it. I don't need to go to jail to find this out.

I figured it would be much simpler for someone on this "Jeep" forum who has a JK and TJ sitting in their driveway to put a tape to the dang thing and settle it.

Thanks,
Shawn
 

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RedRubi2012 said:
Because I dont have a dealership very near to me and furthermore there is no good way to approach the situation. I would probably at the least get some odd looks at the dealership or possibly get asked to leave if I wasn't looking to buy something.

I thought about going down there at night but that might be worse...what if someone saw me creeping around a Jeep at night? They may figure I am trying to sabatage the thing, or steal something from it. I don't need to go to jail to find this out.

I figured it would be much simpler for someone on this "Jeep" forum who has a JK and TJ sitting in their driveway to put a tape to the dang thing and settle it.

Thanks,
Shawn
Why would you go to jail for measuring? What law does that fall under? Last I checked, you can't get sent to jail for far fetched assumptions.
Why would you have to go at night? Why not just go there and ask a salesman what you're trying to figure out and he will probably help you.
And if a dealership is too far... Have you tried calling Chrysler?

And yes this is a jeep forum... But owning two completely stock Jeeps being a JK and a TJ... I don't see that being all that common. If I had a TJ and a JK, one would be modded at least with tires.

Why do you need this info anyways? If its more solid than to just tickle your fancy, I'll go to a jeep dealership and just measure them for you when I'm there for my jeep club monthly meeting this week. But if its "just because", then no, I probably won't do it.
 

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Siren Assassin said:
Why would you go to jail for measuring? What law does that fall under? Last I checked, you can't get sent to jail for far fetched assumptions.
Why would you have to go at night? Why not just go there and ask a salesman what you're trying to figure out and he will probably help you.
And if a dealership is too far... Have you tried calling Chrysler?

And yes this is a jeep forum... But owning two completely stock Jeeps being a JK and a TJ... I don't see that being all that common. If I had a TJ and a JK, one would be modded at least with tires.

Why do you need this info anyways? If its more solid than to just tickle your fancy, I'll go to a jeep dealership and just measure them for you when I'm there for my jeep club monthly meeting this week. But if its "just because", then no, I probably won't do it.
I'm staring to think troll. Any "normal" person would have called and got the measurements. Just saying, I think im like the only one on the forum with a stock vehicle, but mines a yj and I do have the biggest tires on it that I can fit
 

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Discussion Starter #20
@Siren - First off my assumption is not far fetched just because you dont care about the topic. I can't believe I am catching all this flak because I ask a question about jeeps on a jeep forum. I am sorry that I insighted controversy over a simple matter that I had wished to find the answer to in the easiest fashion. I didnt want to go to a dealership and put up with all the salesman bullcrap and waste a half a day while they try to sell me a jeep just so I can get a couple measurements. This is why I would want to go at night...so I dont have to go in and talk to a salesman or anyone else that works at the dealership. It would take me 5 mins to take these measurements assuming they had a TJ and a JK sitting there if I didn't have to deal with anyone, but it would look pretty suspicious to creep around there at night possibly insighting someone to call the cops which is where the possibility of jail came from. But I can see that I have already wasted hours on this forum when it probably would have been easier to do as you suggested. I have not called Chrysler because the "customer service" people typically are not technically oriented and it would probably take much effort to get through to someone who actually knows what they are talking about. They couldn't even tell me the correct ship date for my Wrangler let alone specifications that are not normally listed in the owners manual or on build sheet or anywhere else on the internet from what I have found since searching for this for a couple days.

@Clay - Per Wikipedia "troll is someone who posts inflammatory, extraneous, or off topic messages in an online community with the intent of provoking readers into an emotional response". I'm sorry that you and siren are getting emotional over my question but thats your problem. The posting of this question is relevant to the intent of this forum and to the engineering specifications of the Jeep JK and since I am just about to recieve a new one, questions such as this are not extraneous to me and probably not to other people with stock vehicles. Funny but a comment like "I am the only one on the forum with a stock vehicle" seems like more of a loaded question to get an emotional response from me.

I don't have to install a lift kit or otherwise modify my Jeep vehicle to make me as important or relevant of a die hard Jeep enthusiast as yourselves or anyone else on this forum. And I take offense that you would just dismiss my question and try to single me out. If you don't like the question then don't respond to it.

Thanks,
Shawn
 
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