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Rear end breaking out
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=11573
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Author:  Dutchy [ Sun Aug 20, 2006 10:01 am ]
Post subject:  Rear end breaking out

Since a couple of weeks I find the rear end breaking out much more easely, it happens most often in damp conditions in left hand corners between 20 and 30 MPH when putting the trottle down.
I know the CRD is quite capable to get the wheels spinning in first and second gear but I never had the back breaking out this easy before.
Could it be the limited slip dif. again? Had some problems with it before but then the whole axel was stuck at low speeds.
I checked the tyres, BFG at's with 7mm tread and 33 psi so this can not be an issue.

Any suggestions?

Author:  Jeepjeepster [ Sun Aug 20, 2006 11:56 am ]
Post subject: 

Thats normal. Just dont get on the gas so fast and wait till the jeep is striaght until you get on the gas.

Author:  PitViper [ Sun Aug 20, 2006 12:26 pm ]
Post subject: 

I get that when I leave work. The road has some dirt on it so it makes it easy to break the tires lose. I also have the LSD and it feels kinda strange when it does it.

Author:  hillcountrykj [ Sun Aug 20, 2006 1:01 pm ]
Post subject: 

Yep that is normal. it can be fun doing donuts in the middle of the road :lol:

Author:  Jeepjeepster [ Sun Aug 20, 2006 1:30 pm ]
Post subject: 

hillcountrykj wrote:
Yep that is normal. it can be fun doing donuts in the middle of the road :lol:


Yes, it can be much fun!! :D

Author:  EOD-KJ [ Sun Aug 20, 2006 3:13 pm ]
Post subject: 

yeah like everyone else is saying...its called vehicle dynamics...thats just how cars are :)

any RWD will give you some trouble if youre accelerating in the rain, while turning.....which leads to the popular sport of drifting

Author:  USPLibby [ Sun Aug 20, 2006 5:03 pm ]
Post subject: 

It's much harder to spin the tires with these: :wink:

Image

Author:  LostRenegade [ Sun Aug 20, 2006 9:18 pm ]
Post subject: 

I believe it is normal also. The LSD may make it worse. After installing the Powertrax noslip, I notice that mine slides out rather easy on ice. The first time on ice after the NOSLIP went in, I did a complete circle. I goosed the gas just a bit and boy was I amazed that I spun completely around.

Author:  InCommando [ Mon Aug 21, 2006 2:04 am ]
Post subject: 

The factory tires are really crappy in the rain. Pulling out in front of someone in the rain with the 6-spd can be an adventure if you are not careful with the skinny pedal.

Author:  05JeepKJ [ Mon Aug 21, 2006 2:29 am ]
Post subject: 

Jeepjeepster wrote:
hillcountrykj wrote:
Yep that is normal. it can be fun doing donuts in the middle of the road :lol:


Yes, it can be much fun!! :D


Its especially fun on gravel roads.

Author:  Dutchy [ Mon Aug 21, 2006 7:05 am ]
Post subject: 

Thanks for the input guys!
Have to drive more carefull around corners from now on , roads are too narrow up here to do a donut, maybe half a donut before you have a close encounter of a woolly kind. (sheep)

Author:  VTNomad [ Mon Aug 21, 2006 3:15 pm ]
Post subject:  Rear end

Wow, I thought this was a post about butt zits.

Author:  seanpr123 [ Mon Aug 21, 2006 3:32 pm ]
Post subject:  Re: Rear end

VTNomad wrote:
Wow, I thought this was a post about butt zits.


:lol:

Don't even know what to say

Author:  Jeepjeepster [ Mon Aug 21, 2006 3:52 pm ]
Post subject:  Re: Rear end

VTNomad wrote:
Wow, I thought this was a post about butt zits.


I could of went along time without picturing that in my head. :cry:

Author:  mberthia [ Wed Aug 23, 2006 11:34 pm ]
Post subject: 

Dutchy,

Does your 2003 have a limited slip differential (aka trac-lock) ?
I come from driving a 95 Cherokee with the LSD for 10 years. It never slided much in the rain.
I just got an 03 KJ last month and it does not have an LSD. Wow what a pain in the rain. I can't imagine how bad it's going to be in the snow...

Anyone upgraded to a streetable LSD? and how much for it ?

Author:  Dutchy [ Thu Aug 24, 2006 4:39 am ]
Post subject: 

Yes, my 2003 has the LSD and it can get a bit lively with snow, but having said that, at least both rear wheels are turning the same speed at low speeds and that will get you out of most situations without even using 4hi.
Many softroaders like the Freelander do not have LSD and although beiing permanent 4 wheel drive, will end up as one wheel drive in snowy conditions.
So the LSD is a curse and a blessing at the same time.

Author:  streetKJ [ Thu Aug 24, 2006 6:17 am ]
Post subject: 

Can someone rationally explain how having a limited slip differential can make driving in snowy or dirty roads more difficult than without LSD?

Correct me if I'm wrong here but isn't LSD supposed to provide increased traction to the tire with MORE grip on the road since it is taking the available power away from the tire with NO traction? Since the tire getting the increased power has grip, it would make sense to make use of that available grip to help get the car out of the area where that one (or more) tire doesnt have grip.

If you were driving on an ice rink, you should expect the wheels to slip very easily anyway since the KJ has a lot of low end torque. So say you had a non LSD KJ (open differential) and you were driving in circles on the ice in a clockwise direction (always turning right) then your rear left tire would lose grip first since it receives power and its on the outside, and so it spins at a faster rate than the inside (rear right) tire does. Since it doesnt take much effort to break traction on ice with an open differential, you would have to apply very little gas to get the car squirrly. This means that although your right rear tire has more grip than the left rear, its grip is limited to the same amount as that of the left when it loses traction, which isnt very much.

However if you had LSD, the power lost to the left rear tire spinning would be transfered by the diff to the tire with more traction (the right rear tire), and you are able to go faster until the point where the right rear tire loses traction of its own. The next logical step in going faster is to have an ALL WHEEL drive system in which there is a front, rear, and center differential. A 4 WHEEL drive system in this scenario is better than having just a rear LSD, but not better than ALL WHEEL drive.

To get a better picture of this, read up on differentials on HowStuffWorks, and look at this clip of the Prodrive P2 on Top Gear at about 2mins45seconds when Jeremy drives around in a circle with the active center differential turned off, and then with it turned on. The ACD is basically an advanced LSD which coordinates power and braking force between front and rear wheels quite actively using microprocessors that scan traction conditions at about 300 times per second. This serves to provide maximum traction and elimination of understeer and oversteer at all times in relation to fluctuations in speed.

http://auto.howstuffworks.com/differential6.htm

http://www.youtube.com/watch?v=b0hDqlASKHc

Author:  Dutchy [ Thu Aug 24, 2006 9:57 am ]
Post subject: 

LSD is great in snow and mud when you need it most as it will give traction to both rear wheels by locking up the rear axel, but the problem start when you drive at low speeds into a corner in wet conditions and when you do not expect it to happen, or when you make a tight turn at low speeds, the inner and outer rear wheels turn at the same speed, this means that the inner wheel starts slipping as it has the same speed as the outer wheel but less road to cover, result: rear ends brakes out or at least feels wobbly.

I found this out when I drove on snow in second gear 2hi, pushed the trottle a bit in a corner and without any warning the rear end was gone, I lost total controll, normally you would feel it going and you just counter steer and let go of the trottle, but there was no time.
The only car I owned which could bite you in the but like this was my 1974 VW beetle.

Author:  mberthia [ Thu Aug 24, 2006 10:28 am ]
Post subject: 

The KJ LSD is a clutch type. Would the amount of torque to overpower the clutch be too high for the rainy conditions that you describe ?

Author:  Loopkey [ Thu Aug 24, 2006 12:47 pm ]
Post subject: 

streetKJ wrote:
Can someone rationally explain how having a limited slip differential can make driving in snowy or dirty roads more difficult than without LSD?

Correct me if I'm wrong here but isn't LSD supposed to provide increased traction to the tire with MORE grip on the road since it is taking the available power away from the tire with NO traction? Since the tire getting the increased power has grip, it would make sense to make use of that available grip to help get the car out of the area where that one (or more) tire doesnt have grip.

If you were driving on an ice rink, you should expect the wheels to slip very easily anyway since the KJ has a lot of low end torque. So say you had a non LSD KJ (open differential) and you were driving in circles on the ice in a clockwise direction (always turning right) then your rear left tire would lose grip first since it receives power and its on the outside, and so it spins at a faster rate than the inside (rear right) tire does. Since it doesnt take much effort to break traction on ice with an open differential, you would have to apply very little gas to get the car squirrly. This means that although your right rear tire has more grip than the left rear, its grip is limited to the same amount as that of the left when it loses traction, which isnt very much.

However if you had LSD, the power L.O.S.T. to the left rear tire spinning would be transfered by the diff to the tire with more traction (the right rear tire), and you are able to go faster until the point where the right rear tire loses traction of its own. The next logical step in going faster is to have an ALL WHEEL drive system in which there is a front, rear, and center differential. A 4 WHEEL drive system in this scenario is better than having just a rear LSD, but not better than ALL WHEEL drive.



The situation where an open diff is easier to control than a LSD is when driving in a straight line or starting from a stop on an ice covered/slippery road. I will use the starting from a stop as an example.

Since roads are crowned a open diff will transfer all of the power to the tire with the least traction. You will spin your wheel and start slower but you will track in a straight line because the other wheel has no power and is only providing side-to-side resistance preventing the end from sliding out (Of course with enough power to the one wheel it will still slide out, it's just easier to control with an open diff). With a LSD both wheels have power to them and there is very little side-to-side resistance, the back end will slide out much easier following the crown of the road.

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