Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Straight Axle VS IFS, please explain difference-

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudNurI, Jan 5, 2002.

  1. MudNurI

    MudNurI 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,113
    Likes Received:
    0
    Location:
    VT
    Okay DON"T tell me which one is better for what reason and why you think the other kind sucks- what I am asking is what is the actual DIFFERENCE in the two ??? You guys are all set on what you prefer---but mechanically WHAT is the difference? I know IFS stands for independent "front"?? Suspension- but what does that mean?

    sorry for the ignorance!

    thanks guys!
    Brandy

    LOVING the new Duramax!!!
     
  2. anatomiczero

    anatomiczero 1/2 ton status

    Joined:
    Jun 26, 2001
    Posts:
    418
    Likes Received:
    0
    Location:
    Washington
    Think of a front wheel drive car, looks the same to me.

    ----------------------------------
    soon to have a blazer/jimmy
     
  3. MudNurI

    MudNurI 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,113
    Likes Received:
    0
    Location:
    VT
    I figured that much- but mechanically -- basically WHY did they "invent" it, what is it suppose to accomplish- etc...

    thanks!
    Brandy

    LOVING the new Duramax!!!
     
  4. TorkDSR

    TorkDSR 1/2 ton status

    Joined:
    Sep 1, 2001
    Posts:
    1,258
    Likes Received:
    0
    Location:
    bucks co pa
    well, there have been books on the subject, but ill give you the short and sweet

    in a straight axle, the axle is straightwith the pumpkin in the middle between two solid axle tubes with the axles riding in them.

    on the Independent front suspension there is these droopy things(upper and lower a arms) that come down from the "pumpkin" which is located up higher than the rest of the stuff, so these two flimsey falh shafts run from the pumpkin down to the wheel hubs. the ifs allows fora much more subptly smooth ride. the solid axle allows for more articulation because when one wheell is forced up the other one droops down, the whole axle kinda pivots about its imaginary center


    and thats my description

    "I DIDNT just fall for some sick joke did i"?

    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  5. TorkDSR

    TorkDSR 1/2 ton status

    Joined:
    Sep 1, 2001
    Posts:
    1,258
    Likes Received:
    0
    Location:
    bucks co pa
    OFF road it accomplishes little, but for highway poundin posers its the "sh it" comfort i guess is the answer

    beligerence doesn't justify intelligence.
    <font color=blue>wheelers hate posers.</font color=blue>
    <font color=red>79k15/400/700r4/205/38.5</font color=red>
     
  6. MudNurI

    MudNurI 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,113
    Likes Received:
    0
    Location:
    VT
    THANK YOU no you did NOT fall for some sick joke- I seriousley could not figure out what all the "bickering" was about which was better- I know the new trucks ride better, but thought there must be a reason etc... THANK YOU!

    --Brandy

    LOVING the new Duramax!!!
     
  7. 88jimmyoungowner

    88jimmyoungowner 1/2 ton status

    Joined:
    Nov 20, 2001
    Posts:
    425
    Likes Received:
    0
    Location:
    georgia-rome
    believe me, IFS drives amasing on the street. But my one experience off orad, they dont pull as well. i drive the jimmy in twon, and i feel every bump. I feel nothing on a IFS. each wheel can move on its own. there is not as much flex, but more comfort. That is just my experience on them, i dont know much diference.

    16, 88 jimmy, kearning, but still need help
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    I am sure that a straight axle'd truck could ride just as good or better than an IFS truck if it had the right spring pack up front.

    IFS isn't the only reason new trucks ride better. The rear springs have progressive rated spring packs which are longer and have less leaves. I believe this is a big step in the right direction for ride quality as well.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  9. RockyRider13

    RockyRider13 1/2 ton status

    Joined:
    Jul 11, 2001
    Posts:
    102
    Likes Received:
    0
    Location:
    Kansas
    Here are the hard core facts

    IFS gives a better on-roadride because of un-sprung weight (weight below the springs). It is able to adapt to the terrain faster. Another advantage is having each wheel independant of each other. IFS can hurt you off-road because of reliability and articulation. IFS is prefered on some off-road situaton for stability at high speeds. like desert racing.

    Solid axle = brutaly simple design, used and abused for many years
    IFS = better stability at speed

    hope this is the end of your question

    Be a simple, a real simple man
    -Lynyrd Skynyrd
     
  10. Twiz

    Twiz 1/2 ton status

    Joined:
    Mar 8, 2001
    Posts:
    3,729
    Likes Received:
    0
    Location:
    Clearfield Ut.
    Solid axle, front suspension
    Design;
    A solid axle suspension has a locating beam cannecting both tires togather, permanatly. There is no change from tire to tire, other than steering input and pre-set steering incination angle (neg. camber-gain) *more on camber later*.
    Advantages;
    - Strength and Rigidness.
    - Camber control. The tires will remain consistant in relation to each other, regardless of tarain and body-lean.
    - Simplicity.
    - Travel. A "working" soilid axle can be made to have extream amounts of suspension movement.
    Disadvantage;
    - Heavy-unsprung weight. Un-sprung weight is weight that is carried below the suspension, like the tires for example. If a object is heavy, it will tend to stay in its path and resist a change in direction. (Like a tire over a bump)
    - Bump-steer: Bump-steer is a change in toe when the supension changes postion (toe = tire pointing in or out, from straight ahead postion) Basicly, uncontrold or un-wanted steering in-put in a solid axle design. On a soild axle suspension, there is no way to eliminate bump-steer, but it can be redused to "useable" levels (like for example, useing the ORD cross over steering sys).
    - Shimmy: Shimmy is a uncontrold vibrations of a tire. With both tires connected togather, anything that happens to one tire, will effect the other tire. If for-example, one tire is out-of-round, then it's effects will be transfered to the other tire.
    - Inability to change to uneven road surfaces. Again, anything that effects one-tire will efect the other tire. If for-examble, one tire is on a curb, and the other tire is on the street, both tires will be forced to ride on their outer (or inner) edge of the tread.

    Independted front suspension
    Design:
    Both tires are suspended independently of each other. They are not intercannected. Usualy, the tires are located by unequal length control-arms or links.
    Addvantage:
    - Flexibility of alignment. A independent suspension can be made to set the tire to any position at ride-height and be made to set the postion of the tire in-relation to suspension movement. (camber gain/loss, bump-steer/toe-in, ect...)
    - Ability to change to body body lean. As the body sways into a turn, the suspension can be made to take advantage of this movement and increace cornering force in pre-determined amounts. (neg.-camber-gain)
    - Predictability steering in-put: Again, tire alignment can be set to almost any-position, giveing the driver a feel of "total-control". (toe-in and bump-steer, neg-camber-gain ect..)
    - Lighter un-sprung weight: Less un-sprung weight will have a tendency to change to road surfaces quicker, and therefore, stay in contact with the road. (Allways a good thing)
    - Ability to change uneven road-surfaces. Same example as with the solid-axle above, but the tire can be made to stay vertical, keeping the full width of the tire tread in contact with the road surfaces.
    Disadavantages:
    - Extreamly complex: If you get it right, you win! Get it wrong, and your in a ditch.
    - Maintence: With the ability to set the tire to any given angle, also comes the ability to disturbe the alihnment and genneral wear and tear.
    - Inability to take addvantage of leverage: With both tires suspended independently, no or very little force will be transferd to the opisite tire (has more to do with articulation)
    - Less wheel travel (factory): With several links, at some point the travel of the links will be limited or the intercannecting arcs will bind, decreaseing suspension travel.

    I could go on, if you wish......

    <font color=blue>Wow Factor
    A SBC at 6000 RPM, Piston speed of 60 MPH.
    3- The intake charge reaches a speed 4 X greater than the piston.
    Thats 240 MPH.
     
  11. Twiz

    Twiz 1/2 ton status

    Joined:
    Mar 8, 2001
    Posts:
    3,729
    Likes Received:
    0
    Location:
    Clearfield Ut.
    Toe-in: From the front, both tires pointing in. The tires should be set with a little toe in, as they will be pulled to toe-out by the drag/resistance of the tire. (unless they are powered, like in a FWD)

    Camber: Tilt of the tops of the tire in (negitive) or out (positve).

    Negitive Camber Gain: An incrase in neg. camber as the suspension is compressed (IFS) or a pre-set amount when the tire (steering knuckle) is turned. On a solid-axles and IFS, a factory pre-set amount of steering-incination-angle (negitive-camber-gain) is included to the design of the suspension.
    Negitive Cambe Gain is needed because, when a vehical is in a turn, the weight of the vehical will try to keep pulling to the out-side of the turn. This would force the (outer) tire to ride on it's out-side edge, greatly reduseing traction. Negitive-camber-gain, will help keep the tire flat, with maximum cornering force.


    <font color=blue>Wow Factor
    A SBC at 6000 RPM, Piston speed of 60 MPH.
    3- The intake charge reaches a speed 4 X greater than the piston.
    Thats 240 MPH.
     
  12. MudNurI

    MudNurI 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,113
    Likes Received:
    0
    Location:
    VT
    YOU ARE THE MAN TWIZTID!!!

    thats EXACTLY what I was trying to figure out... I knew someone here would know... THANK YOU.. now carry on with your posts regarding ifs vs straight axle, cause I can join in on them now! LOL

    --Brandy

    LOVING the new Duramax!!!
     
  13. GONZO2

    GONZO2 1/2 ton status

    Joined:
    Jul 17, 2001
    Posts:
    137
    Likes Received:
    0
    Location:
    formerly Great Falls, MT now Lompoc, Ca
    alright not to try and confuse anybody, but how would a dessert runner truck ramp out? these things have like 20" of wheel travel on their suspension set ups, would this help in the ramping process?
    also if ifs is not as strong as solid axle set up, then why would one of the best "factory" off road vehicles, hummer, come with ifs? granted a hummer does not ramp the best, about mid pack when compared to any other factory 4x4. it does some great things off road with out the articulation of some hybrid rock buggy.
    another point the new dodge finally switched over to ifs and according to "dodge test drive" on speed vision now has more wheel travel than it's old solid axle truck.
    anybody want to explain any of these [confused]

    <font color=blue>85 blazer</font color=blue> 4" lift, 35" pro comp mt, locked out back
    <font color=blue>88 blazer</font color=blue>mostly stock
    <font color=blue>99 30th ann. TA</font color=blue>
    <font color=blue>79 TA</font color=blue>
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Hummer is designed that way because all of the parts at all 4 corners are interchangable. That's probably the most important reason it's IFS.

    And it doesn't ramp mid-pack. It sucks, period. It couldn't ramp 1/2 what my truck could.

    Baja suspensions work well for that application but are too expensive and therefore not practical for an every day truck. Besides, not enough people off-road to justify installing that on EVERY truck.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  15. bigjbear

    bigjbear 1 ton status Staff Member Moderator

    Joined:
    Feb 18, 2000
    Posts:
    13,973
    Likes Received:
    453
    Location:
    Marietta GA
    Sure I'd love to explain. First of all the HMMWV is NOT one of the best OHVs of all time. The were designed as a stable platform to rapidly move troops and equiptment on unimproved roadways. They do that well and it would be hard for the intended drivers to hurt themselve to much due to their stability. Even in the place it should excell due to its design (mud-no low hanging parts to drag) its weight hurts it. It ramps unbleavably bad, not middle of the pack. There is more to 4x'ing than an RTI, though. The new Dodge may have more wheel travel (in stock form) but it no longer has front articulation. This because the front wheels are no longer connected-see above. I am guessing here but a desert truck would probally ramp good but they are designed for high speed so the springs most likely are a little stiffer. Any desert racer types want to chime in?
    If you have any more questions please ask.

    Jim '80 GMC & '73 Blazer
    Body by Tellico
    <a target="_blank" href=http://www.tellicok5.rockcrawler.com>www.tellicok5.rockcrawler.com</a>
     

Share This Page