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Discussion Starter #1
how is ground clearance measured?

sounds like an easy questions until you try to find out what is exactly measured. so when manufacturers give the ground clearance what do they take as the lowest point of the vehicle?

Is it the differential at the axle? In case of the KL would that be the lowest part at the wheel hub? If it was the lowest part at the wheel then the ground clearance would solely depend on your wheel+tire diameter and essentially all cars with 65R17 tires should have the same maximal ground clearance. And cars with an axle and a diff should have less than a car with independent suspension.

So how do different manufacturers measure their cars? I guess approach and break over angles are probably more important than simple ground clearance.
 

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Ground clearance should be measured to the lowest point of the vehicle. In a solid axle vehicle this is normally the differential. In a independent suspension it can be just about anywhere.

And you are right about the approach and breakover angles being more important.
 

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Discussion Starter #4 (Edited)
does anybody know how Jeep actually measured the Cherokee's ground clearance? there seem to be no standard how this is done. how are subaru and toyota doing it?

to me it looks like the lowest point is this:
 

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Discussion Starter #6
My guess would be with a tape measure. It would be kind of difficult with a wooden ruler
Funny, I found the same joke in a Toyota forum for the 4Runner 2006. Even more funny it is actually easier to measure with a 10 inch ruler attached to a long stick. That way you can hold it to the various locations from a distance while kneeling next to the car. With the tape measure you have to actually have both hands there to pull it out.

On a more serious note: it seems that manufacturers measure all a bit different. And they usually don't qualify or give details. For example if they measure 8 inch next to the wheel but 11 inch in the middle of the car. This makes it very difficult to compare between cars or predict if your going to hit something or not. There is a ton of threads about this for many brands.

I guess in reality this is done by measuring it acustically. If it gives a scraping sound then it's not enough clearance. Good to have skid plates.
 
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....
to me it looks like the lowest point is this:
Assume you mean the muffler? The suspension arm holding the spring rises as the tire rolls over an obstacle.

For some, clearance is important for not bottoming out in snow/mud. That's easy to determine/measure since it's about the large flat surfaces.
 

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Assume you mean the muffler? The suspension arm holding the spring rises as the tire rolls over an obstacle.

For some, clearance is important for not bottoming out in snow/mud. That's easy to determine/measure since it's about the large flat surfaces.
Yes, if the wheel is rolling over, not next to, the obstacle...

Regarding the bottoming out on snow, stated ground clearance is kind of a hard number to qualify since powder and wet packing snow do different things. I bottomed out so hard in 2 feet of snow this winter in what I thought was powder (but it was 35 deg F so it was a little wet) that I had to shovel for a long time to get free....
 

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.... I bottomed out so hard in 2 feet of snow this winter in what I thought was powder (but it was 35 deg F so it was a little wet) that I had to shovel for a long time to get free....
Ha! Been there too. Trying to get up our 1/4 mile driveway in a minivan. Lot's of shoveling to get out. After that I started measuring clearance before buying vehicles.
 

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Discussion Starter #10
Assume you mean the muffler? The suspension arm holding the spring rises as the tire rolls over an obstacle.

For some, clearance is important for not bottoming out in snow/mud. That's easy to determine/measure since it's about the large flat surfaces.
I actually meant the suspension arm. That is about 8-9 inch off the ground although I haven't measured it yet. The muffler is much higher than 9 inch. I understand that the suspension arm moves up when the tire rolls over a rock.

However the question is what does Jeep measure when they say the ground clearance of the TH is 8.7 inch?
 

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I actually meant the suspension arm. That is about 8-9 inch off the ground although I haven't measured it yet. The muffler is much higher than 9 inch. I understand that the suspension arm moves up when the tire rolls over a rock.

However the question is what does Jeep measure when they say the ground clearance of the TH is 8.7 inch?
I like your idea about the 10 inch ruler attached to a long stick. You could measure your TH on flat ground and list all the parts that come to 8.7". Other than that, this is the only thing I can think of --> http://en.wikipedia.org/wiki/Ride_height.
 

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Ooooooooooh THREAD REVIVAL!

I always wondered about this and when I measured my TH at the lowest point on the front skid plate, it always came out to less than 8.7". The wiki article linked above has the answer - "other than those parts designed to contact the ground."

Now what I need to do is crawl under and measure from anything but a skid plate...
 

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Ooooooooooh THREAD REVIVAL!

I always wondered about this and when I measured my TH at the lowest point on the front skid plate, it always came out to less than 8.7". The wiki article linked above has the answer - "other than those parts designed to contact the ground."

Now what I need to do is crawl under and measure from anything but a skid plate...
Ummm... I think you have a bit of faulty logic there. The skid plates are not designed to "contact the ground", they are there to prevent tender whatnots from damage. A tire is designed to contact the ground.

India, of all places, actually has a standard for that: ARAI mandates new ground clearance measurement norms

The key is that most car companies, including FCA, measure ground clearance with an "unladen" vehicle, or the same weight as measured for "curb weight". That is an empty vehicle, but with all fluids necessary to operate the vehicle. Where some car companies fudge a little is whether the gas tank is full.

So, take everything out of your vehicle and try a measurement. If that doesn't work, try driving until the gas tank is empty and try again. That still might not give you what you are looking for since springs tend to sag a bit with use.

Even approach and departure angles change with load and age.
 

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Hmm true enough. I thought I had a bit of an a-ha moment there, but I see what you're saying.

With that in mind, how long are our stock suspension components supposed to last? My struts and springs are all original as far as I can see, and I've got about 145k kms on em.
 

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With that in mind, how long are our stock suspension components supposed to last? My struts and springs are all original as far as I can see, and I've got about 145k kms on em.
I know you don't have this in Canada, but if you take the Mopar Lifetime Maximum Care warranty at its word, shock/struts/springs should last the lifetime of the vehicle.

While we all know that isn't necessarily the case, they do cover them under warranty. My wife has a 2008 Jeep Commander that we just had new shock/struts replaced under the same warranty. The only charge was the $100 deductible that we have. Personally, I would think of these as wear items, but I guess FCA didn't see it that way.

The Lifetime plan for the KL covers these suspension components:

FRONT SUSPENSION: Shocks; Shock Mounts; Struts; Strut Mounts, Bushings and Bearings; Upper and Lower Control Arms; Control Arm Bushings; Thrust Arms; Upper and Lower Ball Joints; Coil Springs; Torsion Bars; Air Suspension System; Front Wheel Bearings.

REAR SUSPENSION: Rear Leaf Springs; Rear Coil Springs; Auxiliary Springs; Spring Interliner; Spring Bushing; Spring Shackle; U-Bolt Rear Spring; Spring Hanger; Axle Trac Bar; Lateral Link Arm; Shocks; Shock Mount Plate; Struts; Strut Mounting Plates; Strut Bushings; Rear Trailing Arm Assembly; Rear Torsion Arms; Rear Torsion Bars; Rear Stabilizer/Sway Bar; Rear Stabilizer/Sway Bar Link; Rear Stabilizer/Sway Bar Bushing; Rear Wheel Bearings.
 

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I say take a laser distance measure, attach to a ruler then check your distance to the wall or solid obstacle from say behind your vehicle. Start from the left front tire to right front tire(or right to left) at 1 inch increments till the measurement is closer than the obstacle. Then you would know around the exact clearance of your vehicle. Once you get close at say 8 inches all good then 9 inches it returns a closer measurement then you know your close and the laser is hitting an obstruction. Then you could fine tune exactly the height it hits at. But of course you would have to do this on a very level surface.
 
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