Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Check out Ebay#4358052867. Never saw one before but I think I'm in love!

Must be Valentines day,

Marc

nibbler wrote:

It is called a Bobcat       ( skidsteer )                                             18 degrees

Boy, slap a hydro tranny on that baby and kick back and relax.

Quote from Nibbler   "A 4x4 has 4 wheels and 4 driven wheels."

Nibbler,  I believe that what you are describing there is"all wheel drive"  I just browsed your question,  so I will just give you a fast answer here, so sorry if I miss anything.

Let me try and put this in a list for build up of understanding, and there are variences to this such as limited slip being synonomus with a posi, I am not gonna distinguish there, too many keystrokes this is just general OK

-rear wheel drive car only the right rear wheel drives

-positraction rear wheel drive both rear wheels can drive , however it can vary and transfer all the power to either side, in like snow.

-Four wheel drive the standard Has a diff in the front and one in the rear. only two of the wheels drive.  usually the left front and the right rear, This is still called 4 wheel drive. Why I don't know   (this is what you described as "What is being described is a 2x4 with a funky drive train"  no it is not a funky drive train. This is what the standard four wheel drive train is and always has been since the willies jeep and the dodge power wagon, and still the most used and produced today.  

-all wheel drive same as the above 4 wheel drive except the differentials have a positraction system so a lot of time all the wheels drive or it can transfer the power to the wheels that don't slip

-front wheel drive  . almost all front wheel drive cars only have one wheel driving.  Except for the ones on the higher end models that have an option called "Traction Controll"  i.e.  a button next to the gearshift that you push to lock in the other wheel for temporary help say for starting out at a traffic light on a hill etc.  you can only use it temporarily as it will bind on dry roads around bends etc.

Ask your self this question, right after you say to yourself, what do you mean my front wheel drive  only has one of the wheels pulling?  Then why would they offer the expensive option of traction controll?  Or maybe you have a newer Jeep Grande Cherokee.  Look at how it is advertized  You can get select track,  or Quadra-Trac (ok quadra must mean 4  , in this case no, still only 1 on front and one on rear driving,when it senses a slip. (there are different variations of these over the years, no need to waste key strokes and most of them have been skunked/eliminated)      or you can get Quadra-trac2 with traction controll that transfer from the wheels that slip yada yada. (it is no different than the quadra trac sys, it only has the addition of posi units added into the differentials that is the only 4X4 system they have with four wheels driving it is equalavent to all wheel drive.  However all levels of their system are badged a 4X4. (command trac select trac quadra trak quadra trac2  quadra trac 2 with traction controll all say 4X4)  So your statement of "A 4x4 has 4 wheels and 4 driven wheels." could be summed up as that is what it should be, but it actually is not what it is .. Maybe you could call it a cliche'.   similar to the discussions you were questioning on the horsepower overstatements.

So I guees you can do as you suggested there,  don't worry about it and buy more than you need.  Pay the big money for the all wheel drive to insure you actually get what you defined as 4 wheel drive.  I don't think they will ever come out with an advertisement of an 8 wheel drive model on a four wheeled vehicle, cause that would be too obvious they are overstating their product in the first place.  But if they did I am sure their would be some who would buy it.

Buy the way am I saying all wheel drive is necessary.  No my personal preference is the standard 4X4.  no need to pay all that extra money, especially for the cost of fixing All wheel drive, and I believe it is a well known fact that 4 wheel is like 97 percent as good as all wheel drive,(must be cause that is the only kind they made for like the first 50 years of 4x4's, ) in snow and mud and dirt,  does it have a little edge in rock climbing, yes,  but I never seen anyone rock climb with an all wheel drive,  too expensive and prone to breaking in those conditions.  They are good in some high speed racing aspects though,  Subaru is famous for this oversea's races etc.    

Regards Ben07

F Y I That Cub Cadet 4x4 sold on e-bay.  They got the min bid allowed of 500 dol-lazs.

I think good deal if lived close enough for pick-up.   

Ben07 wrote:

From what I have read, the AWD (All Wheel Drive) is like for 4wd but no low range transfer case, not built as tough,  more likely to be automatically engaged, but light in overall weight too.  Like you pointed out ben07, most of us drive a one wheel wonder.  i liked your post          

                                                                18 degrees

Do you think they have a belt to link the front wheels to the rear on this snowblower?

Hi 18 degree,, sry for that long post, and as you recognized thest things are more easily answered in a conversation, preferrably over a beer, so the actual question can be answered by staying on center,  then explore the periferial things.  I know you know what I mean.  And I am no rear-end/ differential expert,  I was however good at blowing them up  .  So with that in mind I can best fast answer your question, not necessarily with the facts first but with some examples,  sry about that.  First the transfer case in your thoughts can be completely left out of the thought process at first., cause it is not directly part of the question,  yes it is part of a 4 w drive.

So here goes  you can indeed have a trans case on an all wheel drive that has 4 high and 4 low.  You can also have an all wheel drive with only the 4 high.  example Jeep G Cherokee has the full blown all wheel drive on their top complicated system and it can all go into the 4 wheel low.

Your question would be then why do some vehicles come without them. (the actual predominanent reason is they started going that direction when putting 4 w d options on front wheel predominanent vehicles  and the following.   The manufacturers and some owners know they will never need or use 4 wheel low even when taking the kids to sports practice in the winter.  So the manufacturers, like that 4 wheel ford thingy, don't put the extra expense in it for a two speed option in the transfer case. It is also very cost effective to leave out on a front wheel based car .. .. A good advertisement I read when like the Acura MDX first came out .  is they noted clearly  the vehicle was very good to get you to your hunting camp on dirt roads,  but it is not meant to be used for things that High and low transfer cases will do. cause it don't have one

I am not an expert on some of the all wheel drive things on like the BMW's and Mercedes,  I did go over a subaru, a little but they don't actually have what I would call a transfer case.  they had some kind of gismo the size of a grapefruit  underneath doin the job,  why,  cause it was obtaining it's all wheel drive from a front wheel drive not fron the standard rear drive models that then goes to 4 w d.  

As you see there are various aspects of things called thus consider to be somewhat the same thing, however it that example you can see if one cones off a front predominant veh and one comes off a rear predominant thing .. the results can be called the same all wheel drive,  but how they accomplish it can be very much different.

Hope I made some sense    Re question if you like as I am sure there are lots that can field your questions better than I and I will still get in and muck it up  a little too

Thx again

Ben07

Ben07 wrote:

Ben,   I think there are a few misconceptions in your post.

-rear wheel drive     The differential shares torque EQUALLY between both rear wheels.  This leads to problems if  traction is poor.  For example if you jack one wheel off the ground torque goes to zero and the wheel spins.  This means torque is zero on the other side too and that wheel can't move at all even if the traction is good there.  Front wheel drive is basically the same except with the drive axle in front

-positraction rear wheel drive  Also called limited slip differential. This design adds a clutch pack or viscous coupling inside the differential to limit the difference in wheel speeds, overcoming the problem illustrated above.  More recently  Electronic Traction Control   does the same thing with a computer sensing each wheels speed and applying the brake to the one that's spinning faster.  There are also special off-road differentials that can be locked to inhibit the differential action completely.  

-Four wheel drive  Also called part-time four wheel drive.  This adds another differential and axle to the front, driven through a transfer case that allows the front to be disengaged. (and often allows a hi/lo range).  Disengagement is crucial because there is no differential gearing between the front and back.  This makes it very hard to turn the vehicle on pavement when engaged and causes excessive wear on the tires and drivetrain on the highway.   Torque is still shared equally left/right but not front/back.  Serious rock climbers like this system often with the full locking differentials described above.

-all wheel drive  Also called full-time four wheel drive.  Same as 4WD except a third differential gear or a viscous coupling is added between the front and back drive shafts to eliminate the problem with part-time 4WD described above.  This system can be left on all the time and no disengagement is required.  May have electronic traction control too.

Naturally there all all kinds of variations to these systems and even the manufacturers are not always consistent in their terminology.

-Bob

Bob, how you worded all of it is correct except  posi-trac is not limited slip. Limited slip is limited slip and posi-trac is posi-trac. With true posi-trac, both rear wheels share the load equally and constantly, they are locked, I used those rear ends on my off-road racer. Limited slip diff's are what you find as optional rear ends on our trucks, suv's and some cars, usually accompanied with a lower rear gear as well.

Bob I am aware of the additional applications etc and other things that complicate the issue that is why I started that post out with the following statement.  and there are variences to this such as limited slip   and I am not gonna distinguish there, too many keystrokes this is just general OK

If I would have added all the stuff about part time full hook-up  and full time viscus joints and chain slack viscus slippage etc etc.   I don't think the person would have been able to get thee general idea etc.  And yes  I am glad to see that there are those (Marshal in this case)that understand there is a difference between limited slip and full fledge posi traction.

Now for your question of jacking the car up and the power transferring. etc.  If you take a vehicle with an old fashioned rear end , no limited slip, and no posi,  just the standard ring and pinion (called a single action rear end),  you raise the right rear wheel and that car will not go anywhere  and that is the only wheel that will spin. And I stated I was leaving limited slip out of the equasion,  your disagreement assumes that limited slip is there. mine does not.

Best way to describe limited slip, is that it doesn't quite transfer power to the left side. However it will pick up some (absorbe excess thru the system) of the power if there is an excessive amount of slippage in the primary drive tire.  Here's an example  limited slip rear end   Fast start so you will put down some rubber,  only the right rear wheel will spin.  now do a real agressive fast start, as in dumping the clutch and really spinning the rear,  in this case both rear wheels will break at first, at the beginning of the burn  then the left one will stop after lets use some nunbers here.  from start of dump  both wheels will leave a tire mark for say 20 feet then left will stop leaving the rubber trail and the right one will continue marking for say another 20 feet.  Summary.  two tire marks  but the left one will be shorter..  ( I am sure you have seen these type tracks out on like country roadds where some one was doin a little excessive horsepower burn outs.  One tire line longer than the other.  Take that same vehicle on some dirt, hit he gas just enough to spin the wheels and both will spin in the dirt, hard to diffrentiate there.

Take your standard dual differential 200 hp suv out on some drive pavement and jump on it,  you may be be able to get a little chirp out of it,  get out and look and you will see the only two tires that marked are the lf and the rr.  even if they do have limited slip. 

Thanks for your key strokes on the posi units Marshall,,  and remember when you change the gear 90 w oil,  don't forget to add the posi clutch additive  which I might add the limited slip or single action don't need

Ben07

Marshall,  I recall "Positraction" is a GM name and perhaps they performs differently  than other limited slip diffs. However, the use of a clutch to prevent one wheel from spinning with respect to the other while still allowing slippage in turns is essentially the same.  I always felt the difference was more a Chevy - Ford thing than anything fundamental.  

Ben,   I thought you were saying in a conventional diff. axle only the right wheel drives.  The torque is shared equally in an ordinary diff.    The reason why the right wheel on the back axle tends to break free first  (and the left front in your SUV)  is because of drive shaft torque.   Think about it.   Under hard acceleration the drive shaft wants to twist the axle and this takes some weight off one wheel.    -Bob