Sponsored

Maximum speed in 4H ?

rcadden

Well-Known Member
First Name
Ricky
Joined
May 4, 2021
Threads
85
Messages
2,646
Reaction score
5,580
Location
Fort Worth, TX
Vehicle(s)
2021 Hydro Blue Sahara Altitude
Build Thread
Link
Occupation
Marketing
Clubs
 
4WD =/= AWD.

So. many. people. get these two things confused (I did at one point, as well).

They are very much not the same.
Sponsored

 

TheRaven

Well-Known Member
First Name
Kevin
Joined
Oct 22, 2020
Threads
5
Messages
1,458
Reaction score
1,958
Location
Reading, Pennsylvania
Vehicle(s)
2021 JLU 80th
Occupation
Electrical, Mechanical, and Aerospace Engineering.
There was another thread on this a couple years ago and there was wide agreement that the answer to this question is "somewhere around 40mph". The reason is not that the mechanical system is limited in some way, it's that if you are able to safely surpass 40mph, you don't need 4WD. If you choose to surpass "somewhere around 40mph" in 2wd and end up losing traction and going off the road, it's not because you were in 2wd...it's because you were going too fast.
 

mwilk012

Well-Known Member
Joined
Mar 10, 2018
Threads
14
Messages
8,926
Reaction score
8,754
Location
Oklahoma
Vehicle(s)
2018 Ocean Blue JLU Rubicon
Occupation
Service
4WD =/= AWD.

So. many. people. get these two things confused (I did at one point, as well).

They are very much not the same.
ehh, itā€™s a pretty arbitrary distinction. Part time 4wd and full time 4wd are better descriptors for the options we have on our Jeeps, but AWD isnā€™t wrong either.
 

AcesandEights

Well-Known Member
First Name
Aces
Joined
Aug 19, 2021
Threads
29
Messages
3,224
Reaction score
6,239
Location
So. Oregon
Vehicle(s)
2022 Jeep Rubicon 2D, with extra guacamole
Occupation
I'm often occupied, by many things, often at the same time
...'bout a hundred dollars.
 

AcesandEights

Well-Known Member
First Name
Aces
Joined
Aug 19, 2021
Threads
29
Messages
3,224
Reaction score
6,239
Location
So. Oregon
Vehicle(s)
2022 Jeep Rubicon 2D, with extra guacamole
Occupation
I'm often occupied, by many things, often at the same time
How fast can you go in 4H if you remove the rear driveshaft?
 

Sponsored

Tredsdert

Well-Known Member
First Name
Greg
Joined
Aug 4, 2020
Threads
70
Messages
3,100
Reaction score
5,326
Location
North Texas
Vehicle(s)
2020 Subaru Forester, 2021 Jeep Wrangler
Build Thread
Link
Occupation
Beer Distribution
Thats really not a very good idea. Water on the road isnā€™t a good reason to be in 4WD.
You should check out my build thread, I'm full of great ideas!!
Jeep Wrangler JL Maximum speed in 4H ? friends-joey-tribbian
 

Alan_Hepburn

Well-Known Member
First Name
Alan
Joined
Dec 15, 2021
Threads
6
Messages
150
Reaction score
218
Location
San Jose, Ca USA
Vehicle(s)
2020 JT Sport S, 2022 JLU Sport S
Here's a tip..... If you're in a hurry to get to Tahoe and you're driving on a snowy highway 50, leave a lot earlier so that you get there in one piece, and you won't kill anyone else with wreck less driving.
It won't be "wreckless" driving if an accident is involved - quite the opposite! :CWL:
 

MrMischief

Well-Known Member
Joined
Apr 25, 2019
Threads
43
Messages
633
Reaction score
1,865
Location
Colorado
Vehicle(s)
JL Rubicon
Thats really not a very good idea. Water on the road isnā€™t a good reason to be in 4WD.
Do know their Jeep? Could be on drag slicks. Would be perfectly reasonable to be in 4x4 on wet roads then. As long as your'e going straight enough, or there is enough slip between the tire and the ground, 4 hi can be used in any condition at any speed.
 

MrMischief

Well-Known Member
Joined
Apr 25, 2019
Threads
43
Messages
633
Reaction score
1,865
Location
Colorado
Vehicle(s)
JL Rubicon
there was wide agreement that the answer to this question is "somewhere around 40mph". The reason is not that the mechanical system is limited in some way, it's that if you are able to safely surpass 40mph, you don't need 4WD. If you choose to surpass "somewhere around 40mph" in 2wd and end up losing traction and going off the road, it's not because you were in 2wd...it's because you were going too fast.
meh that's the problem with statements like "wide agreement". You're essentially taking a poll and most people seem to live in cities, on the coast, where conditions seem to be consistent. I'll throw my Jeep in and out of 4hi with the cruise set at 80 without giving it a second thought. Just depends on what I see coming. I-25 in Wyoming in the winter is frequently clear during the day, except for the wet patches from snow blowing across. When the sun goes down that freezes into black ice for a car length or two. Just enough for a two door jeep to get sideways enough to be scary. "Slow down to 40" you'd probably say. That's fine but it may be 50+ miles before you come to that again, and everyone else is running at the 80 mph limit or faster.

People should do what is appropriate for their situation. Often that 40 mph thingy is probably right in Denver otherwise you're bouncing off the 10,000 other cars on your commute. But those aren't hard fast rules and depending on where a person lives it may not even be a decent guideline.
 

TheRaven

Well-Known Member
First Name
Kevin
Joined
Oct 22, 2020
Threads
5
Messages
1,458
Reaction score
1,958
Location
Reading, Pennsylvania
Vehicle(s)
2021 JLU 80th
Occupation
Electrical, Mechanical, and Aerospace Engineering.
meh that's the problem with statements like "wide agreement". You're essentially taking a poll and most people seem to live in cities, on the coast, where conditions seem to be consistent. I'll throw my Jeep in and out of 4hi with the cruise set at 80 without giving it a second thought. Just depends on what I see coming. I-25 in Wyoming in the winter is frequently clear during the day, except for the wet patches from snow blowing across. When the sun goes down that freezes into black ice for a car length or two. Just enough for a two door jeep to get sideways enough to be scary. "Slow down to 40" you'd probably say. That's fine but it may be 50+ miles before you come to that again, and everyone else is running at the 80 mph limit or faster.

People should do what is appropriate for their situation. Often that 40 mph thingy is probably right in Denver otherwise you're bouncing off the 10,000 other cars on your commute. But those aren't hard fast rules and depending on where a person lives it may not even be a decent guideline.
Problem is, 4wd does nothing for you at 80mph. I don't blame you for not wanting to drive 40mph on a highway that's 95% dry...but if you see an ice patch coming up while cruising along at 80mph throwing it in 4wd is doing nothing but taking your attention away from the impending challenge.
 

Sponsored

MrMischief

Well-Known Member
Joined
Apr 25, 2019
Threads
43
Messages
633
Reaction score
1,865
Location
Colorado
Vehicle(s)
JL Rubicon
Problem is, 4wd does nothing for you at 80mph. I don't blame you for not wanting to drive 40mph on a highway that's 95% dry...but if you see an ice patch coming up while cruising along at 80mph throwing it in 4wd is doing nothing but taking your attention away from the impending challenge.
The JL you're probably right thanks to the electronic aids. My TJ would spin up the rear tires and go sideways when in 2wd. In 4 hi the tires seemed less likely to spin and when it did it understeered going mostly straight rather than the back stepping out.

But if 4x4 really did nothing at higher speeds, then why were 4 wheel drive F1 cars a thing, and seemed to be very strong in the wet. The Ferguson P99 immediately comes to mind, winning Oulton Park in the wet.
 
Last edited:

Rustynail11

Well-Known Member
First Name
Scott
Joined
Mar 7, 2022
Threads
31
Messages
730
Reaction score
1,097
Location
Mansfield, TX
Vehicle(s)
2022 Wrangler JLU Rubicon
Drive to the conditions of the road! Roads in Dallas/Ft Worth are a big sheet of ice today. Just had to get my wife to the hospital for work and my average speed was probably 35 mph mostly in 2H but did go in to 4H for one steep/high overpass. There were idiots passing me like I was standing still. It was satisfying when I came over a hill and saw one of those idiots spun out facing the wrong way crashed in to the concrete divider.
 

TheRaven

Well-Known Member
First Name
Kevin
Joined
Oct 22, 2020
Threads
5
Messages
1,458
Reaction score
1,958
Location
Reading, Pennsylvania
Vehicle(s)
2021 JLU 80th
Occupation
Electrical, Mechanical, and Aerospace Engineering.
But if 4x4 really did nothing at higher speeds, then why were 4 wheel drive F1 cars a thing, and seemed to be very strong in the wet. The Ferguson P99 immediately comes to mind, winning Oulton Park in the wet.
F1 cars have to continually decelerate and accelerate for turns, and they need to take those turns on the absolute ragged edge of grip. You're talking about driving a solid axle box 80mph in a straight line. Having all four wheels powered did zilch for those F1 cars at 200mph on the back straight...but it made a big difference when the driver mashed the throttle at the apex of the turn before the straight.

Basically the case for AWD race cars is totally different than the case for your 4wd Jeep. 4wd is for additional traction during acceleration whether in a straight line or turning. It is not going to do anything for you when your tires have already lost all traction and you're sliding sideways on ice or snow. The last thing you want to do is subject your front tires to more stress by adding power. You want to stay off the gas and steer in the direction you want to go in order to give your tires a fighting chance of saving you.
 

Shibadog

Well-Known Member
Joined
Dec 28, 2021
Threads
16
Messages
1,903
Reaction score
3,117
Location
Bowling Green, Ky
Vehicle(s)
2020 Wrangler Sport S hardtop
Occupation
Safety &Fire Protection Engineer (Retired)
Drive to the conditions of the road! Roads in Dallas/Ft Worth are a big sheet of ice today. Just had to get my wife to the hospital for work and my average speed was probably 35 mph mostly in 2H but did go in to 4H for one steep/high overpass. There were idiots passing me like I was standing still. It was satisfying when I came over a hill and saw one of those idiots spun out facing the wrong way crashed in to the concrete divider.
And Iā€™ll bet some of these clowns were in ā€œ4wdā€šŸ˜. Iā€™ve said for decades that if youā€™ll put it in 4H in the snow and then drive like it was a 2wd rig you can go anywhere.
 

dumpsterRatz

Member
First Name
Dumpster
Joined
Dec 11, 2022
Threads
3
Messages
10
Reaction score
10
Location
socal
Vehicle(s)
JLU
Ive been using 4h for heavy rain a lot more lately. without it my JLU loses traction and the rear steps out when hitting small puddles.

OP got an earful from jeepers reminding him what's safe. the answer is definitely as fast as you'll need. 4h was comfortably moving along at 75mph for me in rain.
Sponsored

 
 



Top