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Technical The pros and cons of a locked rear from those who have or want to

Discussion in 'The Hokey Ass Message Board' started by porknbeaner, Nov 24, 2015.

  1. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    I agree with what your saying, but not your conclusion. The consequences of the "snap oversteer" in the wet will be FAR WORSE with a locked rear than a limited slip, and I base that on first hand experience. Do you have any experience driving cars with higher rear roll resistance(slapper bars/Cal-Tracs/ladder bars/split rear bones) lockers and limited slips in the rain? I do. If a limited slip equipped car gets loose in the wet, it will slip one tire, and be much easier to control than the car with a locker, based on first-hand experience. And no, your 50/50, 100hp cortina doesn't count here.
    Once the car with the locked rear starts to go, it will go hard and sudden, and it will be much harder to bring back into line than the car with the limited slip. Tell, you what Keryzll, if you ever get over here, I'll drive you to a nice big parking lot with nothing to hit, and you can see how well your road-racing theory applies. I'll bring a camera, it'll be a big hit on you-tube. I'm not gonna continue the pissing match. Keryzll can tell all you guys how safe the locker is on a wet road based on his experience driving his cortina, and yall can test his theory on your nose heavy, 400hp hot rods. Post video.
    Got the t-shirt. Honestly, never should have responded to this on the open forum, and Benno never should have posted the question on the HAMB.
    If you look through this thread, and discount the 4X4 experience, we have half a dozen guys with EXPERIENCE running lockers and spools in nose heavy, hot rod type cars and the consensus is pretty consistant, except for one guy, who is basing his conclusions on driving a Cortina on the street, and a corvette on road-racing circuits. Draw your own conclusions.
    Last edited: Nov 28, 2015
  2. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    One more comment here, one thing that Kerynzell says that I DO agree with, the imbalance between front and rear roll stiffness is a factor, and as I mentioned in an earlier post, my gut feeling is that the Cal-tracs may be may be exacerbating the wet weather squirrelyness as compared to slapper bars, because they have more initial roll resistance early in the suspensions motion than slapper bars. In other words, they are acting like a REAL stiff sway bar. Of course early ford rear split bones would be about the worst case scenario in this regard.
  3. slammed
    Joined: Jun 10, 2004
    Posts: 8,161


    Take the time to see the same names back slapping each other over & over on thread after thread. Patterns and habits shall become crystal clear. Egos fed.
    H380 likes this.
  4. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,000


    That's called a locker. If it is open then locks up it is either a posi or a limited slip depending on who you are talking to.

    That is why I chuckle when I hear about someone saying that they spun one with a spool in the set. A spool by nature won't pull you around either will a locker because you have both wheels digging equally all the time (well most of the time with a locker). What will spin you quicker than anything else is one wheel spinning then all at once the other trying to grab. One wheel dragging is what sets you into a spin, or with a locker or spool one tire at a lower pressure than the other. Unequal traction is a killer with any rear.

    That only really works with people who have an ego to stroke. perhaps that is why I seldom get a back slapping, not that I don't have an ego but no one gains any brownie points by stroking it. LOL I do occasionally get a back of the head slapping, but I usually deserve it.
  5. manicmachanic
    Joined: Sep 19, 2006
    Posts: 366

    from Berwyn, IL

    Spools on street cars? A real nono. Ask Bob Stange, he'll tell you. I ran a '62 Cat on the street w/88 and 462 4/speed, 10.5 RaceMasters. The only thing that saved my ass were the slicks!
  6. Avgas
    Joined: Dec 31, 2007
    Posts: 281


    I run a T bucket with a 5.14 -1 gear set, 18" of rubber each side with Hallcraft spindle mounts, its hard on the car an roundabouts, chirps the tires on corners but is positive when you plunge the gas pedal. Maxi spool in my 34 coupe 3.9 final drive, 8.20 wide whites, very drivable with such a small contact patch, done 50 000 miles on this rear! next build V8 Halibrand with a mini spool! I prefers to drive a car that feels like a hot rod rather than a street rod!
  7. seb fontana
    Joined: Sep 1, 2005
    Posts: 5,864

    seb fontana
    from ct

    Quick Performance has spools for 9" for $68..Mini's for $16.50...:D
  8. hinklejd
    Joined: Jan 20, 2010
    Posts: 145

    from Amarillo

    I've had a locker in my DD for the last 118,000 miles (same vehicle) and between that and the open that was in there before, I'll take the relatively harsh operation of the locker any day. The locker makes it much more predictable - although throttle steering in long corners (like cloverleaf corners) is much more pronounced. Between this and a 102,000 in another DD with a limited slip (same vehicle) the LS gives smoother operation. But like was said, the LS lets one tire slip and gradually applies power to the tire that's not moving. This is reverse operation from the locker, where both tires turn together until friction (rotational delta) causes the differential to unlock. If I wanted to go fast in a straight line I'd absolutely prefer a spool, but then I'm a fan of turning at some point, or LS it is.

    Both LS and locker have their place and appropriate installation application. The LS is smoother in operation yet gives up some traction when the one tire first breaks loose - the locker is significantly more harsh in operation but keeps both tires operating together.
  9. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284


    Well you pretty well much have repeated what I was explaining.
    A spool will only aggravate an already understeering car.[which can be dialled out with suspension tuning]
    Oversteer is too much rear roll stiffness , and drag race ladder bar suspension is the worst culprit.

    Put your car in a carpark or what I prefer "a skidpad" and you nightmare can be remedied with suspension / tyre mods [without removing the spool]

    By the way a Lotus Cortina has more than 100hp that you're trying to downplay. And on the track we are at the absolute limit of adhesion [if we're not, some hotshoe is and he's passing us]
    A race car would never be unpredictable with traction on the street because it would never be driven to a "conservative side of having an accident"
  10. langy
    Joined: Apr 27, 2006
    Posts: 5,735

    Member Emeritus

    I had the same issues with the strange spool in my Willys, also noticed steering was heavier, I changed to an Eaton truetrac and it's so much better.
    The spool and damp road wasn't a great combination !!!
  11. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    Well no, I haven't "repeated what you are explaining", I have agreed with some of what you have said, and if you had been actually reading what I said in earlier posts, I said it before you got around to it (see post 45 for front bias/high polar moment of inertia, and post 54 for reference to rear roll resistance re: Cal-Tracs being part of the problem). What I disagree with is your conclusion that a locker has no negative effect on wet weather handling in a high hp, nose heavy vehicle, relative to a limited slip.
    Well, my "nightmare" as you put it can be mitigated, not remedied and I am well aware of how to to do it. Surely someone with your road-race background isn't trying to say that a vehicle with a 58% front bias and an exceedingly high polar moment of inertia can be cured of evil transitional characteristics with sway bars and shock tuning?
    The cure comes at the cost of ruining the cars straightline dry weather performance on the street and at the track, and that is not a trade-off I have any interest in making, especially in light of the fact that I will be tossing dead-hook at the track out the window for cornering/transitional characteristics that will still only rate as on the downhill side of mediocre at best.
    Road-race guys always seem to operate on the assumption that drag race suspension set-up isn't set-up at all, and that drag race guys have their cars set up the way they do because they don't KNOW how enough about suspension set-up to make them "handle" in the traditional sense of the word, nothing could be further from the truth. I have been involved with some very successful autocross cars, and grew up in a road-race family, drag race style suspension set-up is no less sophisticated, its focused on different and more focused goals.
    I stand by my original statement. In a typical hot rod type car with a pronounced front weight bias and lots of power, a locker or god forbid, spool (which is even locked up throttle off, and gonna be REALLY spooky) is a real handful in the wet, and a limited slip will be more manageable in the wet. The limited slip will get "loose" just as easily, but once it does, it will slip one wheel, and it wont continue to come around on you with the same violence as the locker will.
    If you still doubt this, you need some seat time in high powered, front end heavy, live rear axle vehicles in the wet. God knows, I have a TON of it, and pretty much everyone else that is posting on this thread, and has that same experience is saying the same thing.
    Dry surface, straight line, I will take the locker every time.
    Last edited: Nov 29, 2015
  12. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140


    That's why I run them. Tried the rest, wasted a ton of money.
  13. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    On the subject of going fast in a straight line, and I am just throwing this out there, I remember back in the mid seventies, Don Carlton talked about testing a spool in his Colt vs a sure-grip, and I recall him saying that the sure-grip was actually a hair quicker than the spool due to its ability to compensate for variations in the track surface. Its not really pertinent to this thread, but I remember reading it at the time, and being surprised. I will take a look and see if I can find it, if I can, I'll post it here.
    On the subject of skidpad testing as a way to cure a transitional problem in a nose-heavy vehicle, I just don't get it. Skidpad testing is used for developing maximum steady state lateral grip, and has nothing directly to do with a vehicles transitional behaviour. And if you follow skidpad testing to its natural conclusion (chasing ever-increasing, steady state lateral grip) in an inherently understeering (front bias combined with high polar moment of inertia) vehicle, you are probably going to exacerbate twitchiness and unpredictability at the limit of adhesion, not improve it.
    I would also be willing to bet that an inherently understeering, nose-heavy vehicle would be quicker around a skid-pad (steady state, constant radius grip is what you are testing here) with a limited slip than it would be with a spool or locker. And skidpad testing is by no means a catch-all tool for improved handling as defined by how a car corners.
    But we are getting WAY OFF the original question of locked vs limited slip in a street driven vehicle here.
  14. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,152

    dirty old man

    The only truly "locked" rears I've had were welded spiders on dirt track cars with the old style single split 3/4 ton Ford rear axles. Even after I went to a champ QC I stayed with the welded spiders cause I was always trying to save a dollar where I could.
    For street use, my first limited slip was in a Dana 44 under a '53 Stude, sbc powered. Was outta a '57 Golden Hawk and used cone clutches, loscked really solid when you spun 1 wheel, and I did a 360* spin the first time I nailed it in the wet! Always worked well though, except once in a while it was a little stubborn to unlock after it locked.
    Bought a 31"A" hiboy as an uncompleted rolling chassis, with 9" Ford and Power Trax locker. Works well most of the time, but can sometimes squeal the inside tire on city street corner turns, and sometimes you get a bang and a jerk outta the rear when you change lanes or turn right after you have caused it to engage and lock and it unloads with some "twist" still present.
    Bought my '40 as a runner and it has an 8.8" Explorer rear with factory limited slip. Smooth as silk, but since it's a cruiser and not often driven really hard, I dunno how well it works in an unequal traction, heavy throttle situation.
    My OT '03 Sulverado/Duramax 2500HD has a unit from American Axle that is a true locker that utilizes a sort of governor to disengage it once you hit 8-10 mph. You can tell its a locker on tight city corners if you use too much throttle pulling away from a stop sign and turning sharply.
    Every one of these limited slip and lockers have had their pros and cons, but if I were to ever buy one to install in a vehicle I already had, I think I'd take a long lopk at a True Trac.
  15. Doctorterry
    Joined: Sep 12, 2015
    Posts: 671


    My dad runs a spool in his '57. It makes for fun burn outs but you'd better eat your meat and taters if your gonna turn that dude around a corner with no power steering. Of course that's coming from a scrawny kid like me
  16. stubbsrodandcustom
    Joined: Dec 28, 2010
    Posts: 1,077

    from Spring tx

    I prefer a locker myself... but have ran both.. spool does put added pressure on axle shafts.. but if your rear tires are grabbing and your trying to turn expect the front wheels to scrub... Its a matter of personal preference in my eyes.. some people like the rear hop wiggle and hearing a tire chirping in corners.. both do the same thing ultimately... but when you start factoring out the $ figure... spool is way cheaper.
  17. I run a mini spool in the 9 inch in my coupe with 28 spline axles and 4.33's. It needs as it makes pretty serious power and has a 4 speed. I abuse it regularly and I have no complaints. For the little cost, I can put up with a little hop in TIGHT corners. I will do it again.

    51farmtruck likes this.
  18. 51farmtruck
    Joined: Jul 23, 2007
    Posts: 829


    I run a spool in my 32 sedan. It runs a 9" with a strange nodular center section, spool and 35 spline axles. It has a muncie 4 speed, pete and jakes ladder bars, model a rear spring with fairly wide tires (10.5" tread). I drive it quite a bit, its been to Bonneville, numerous rain storms, drag race, all in and around my town and WA state. I beat the hell out of it every time I drive it. Sure it chirps the tires around corners (squeals on concrete) and doesn't have the absolute tightest turn radius, but I knew that going into it. I would also do it again. Just my actual first hand experience.
    slammed likes this.
  19. Beats the crap out of welding up spider gears.. which can break loose in time. I had a mini-spool in the Lincoln 9" rear under my Nova stock car.
  20. Terraizer
    Joined: Jul 18, 2006
    Posts: 456


    I have driven spool equiped rigs on the street and daily for years, both where scouts with 12.50 wide tires. One is a Scout Terra with a 121" WB and you really don't notice the spool much , the other was a Scout 2 with 100" WB and that one handled bad, it would push through corners and felt like it was lifting a front tire when pulling into a parking spot. So i would guess the wheelbase makes a difference.
  21. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,000


    Wheel base makes a difference on about anything we drive, also front to rear bias. Short wheel base vehicles are less forgiving. Even without locked rears they are a bear in the slick, they will swap ends with you real quick if you are not paying attention.
  22. Lytles Garage
    Joined: May 6, 2011
    Posts: 613

    Lytles Garage

    Have had a spool in my BBC, 4 speed, Frankland Quickchange Model A pickup for 15 years, other than breaking the Absolute JUNK Dutchman axles the first time out!! replacing them with Mark Williams QUALITY Axles, Love the way it drives!! REAL HOT RODS run Spools !! Put the HOT back into Hot Rods !!!! Chris
  23. dumprat
    Joined: Dec 27, 2006
    Posts: 2,270

    from b.c.

    I am kinda surprised nobody has mentioned roll steer or how it works with a spool or locker.
    Get it right and you never have a problem, get it wrong and it will fight you on every corner. Couple that with a parallel four link and things don't wanna turn.

    You never even notice the Detroit in my daily unless turning a corner that is more than 90degrees. Even in the rain. And that is with wide tires and 103" wheelbase.
  24. raven
    Joined: Aug 19, 2002
    Posts: 4,199


    "REAL HOT RODS run Spools !"
    I agree, no wimps here.
  25. stealthcruiser
    Joined: Dec 24, 2002
    Posts: 3,719


    Way to go, porknbeaner, ya' damn pot stirrer! :D
  26. DSCF0273.JPG You guy's crack me up..... I ran a spool for years....Street MT's and slicks..... 18'' wide. NEVER had a problem,BUT, and I mean BUT- it's how you drive and how you maneuver.....
    No- it's not an OT that you get in and go......... I never had a prob with chirping,bouncing,clanking, whatever.........
    Never tried to turn on a dime either.........
    Street driving was as seemed to me normal,despite the noise (HP barking)
    IDK what the issue is,and how people's perceptions are, BUT, there all always adjustment's to be made.....
    There's always two camps= love /hate...........
  27. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140


    I guess what it comes down to is how you plan on driving your car, and what the roads look like where you live. Do they look like a drag-strip or a road race course?

    Where I live, they look like a road race course. I may only have 200-hp, but with my tuned suspension, six-speed, and TrueTrac equipped 8.8, spinning 5.13's, I will be seven corners ahead of you when you smash into the guardrails, or wrap around a light pole, in your dragster.
  28. dudley32
    Joined: Jan 2, 2008
    Posts: 1,931


    I ran a spool in a '55 Chevy (10 bolt)... I also had 3 inch aluminum lowering blocks...tight turns and chirping tires destroyed the blocks...:rolleyes:...oh well...
  29. flamin01a
    Joined: Jul 23, 2005
    Posts: 78


    I know this sounds weird, but I credit a spool for saving my life and a 5 year old passengers life as well! While driving a friends t bucket to a rod run in Helen, Georgia, we ran into a full blown thunderstorm that was so dark, it looked like nightime. There was no rain yet, So I speeded up to outrun the rain? A lightning bolt came down and hit the top of the windshield! It blew both of my hands off the T steering wheel and knocked me out. The T went to the right side onto gravel then headed for the pine trees. Of course the spool slowed the car down immediately! My passenger was pulling on my arm and yelling. I woke up and stopped the car before it went into a pine thicket. Without that spool back there, I know we would have been into those Georgia Pines. I know this story will open another post about lightning striking a car! If so, go ahead, I have an answer.
  30. A question for Gimpy or others running trac-loc: I recently got my 10 year build avatar almost on the road. Pretty much stock suspension with a rebuilt/modified diff. I had a well-referenced shop do the wrork including change the open to a trac-loc of his choosing since I'm pretty ignorant in these matters. He went with a Yukon unit he said was pretty much a copy of the Eaton. The car is talking to me going thru slow tight turns, quiets immediatly when car is straight. I really wasn't expecting this, but is it normal? I must add I am really hard of hearing, so I'm only about 80% sure it's coming from the rear end. The car was not driven before the trac-loc was added, so I don't have a before and after reference. Thanks guys....and excuse my ignorance, that's why I come here for answers.

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