I was running my mower awhile ago, and I just started to think about it now. I have an unlocked diff cause I go trailing instead of mudding (flexibility and what not) ANd I was racing around my yard at about 15 MPH, and I turned and it slowed down....It actually was trying to tip over, but when it started to lean, the unlocked diff started to turn the wheel in mid-air, making the other wheel lose power and slow the tractor. Has anybody else actually though of this?
Chopperhed Moderator
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Age : 57 Join date : 2012-10-14 Points : 5057 Posts : 801 Location : Edmonton, Alberta, Canada Eh!
Ive tipped the Rally twice so far, once actually ejected me down a 3' embankment (into snow), and I had no problem flipping it over. Mostly because since I have a Vtwin I didnt want oil getting on my cylinder.
Open diffs are fine for slower speeds, and off road. If you are going over 20mph on pavement, and use the stock brakes, be prepared to crash. One tire will lock up, unlock, then the other tire will do the same, causing a violent swerving motion. I've darn near crashed one doing this, very lucky I didn't.
As far as one tire spinning in a corner, it will slow you down, quite a bit at times, if you are racing. We got very good at high speed, 2 wheel corners on the old machines with the locked diffs. They were taller and narrow, very tippy. Newer ones are lower and wider, and very rarely tip. Most of the time they slide.
Heres a video of what you can do with a locked diff, we did it at much higher speeds when racing.
The tractor will stop, the problem Stretch brought up happens when you lock them up on pavement. The open diff death-wiggle is a scary feeling.
It's funny - as often as Ive left my differentials open, and used stock brakes... I never had the death wiggle occur. Pavement or otherwise... *shrugs*
Stretch44875 Administrator
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Age : 49 Join date : 2012-04-05 Points : 5504 Posts : 959 Location : Mansfield, Ohio
The tractor will stop, the problem Stretch brought up happens when you lock them up on pavement. The open diff death-wiggle is a scary feeling.
It's funny - as often as Ive left my differentials open, and used stock brakes... I never had the death wiggle occur. Pavement or otherwise... *shrugs*
Some stock brakes don't have enough stopping power to do it. If you can skid the tires at high speed, that's when it can happen.
i plan on traveling on pavement but not locking the brakes up and skidding to a hault
Panic stops are rarely planned.
An open diff at speed on loose gravel can net you some freaky results too. I built my kids' go kart with a diff axle from an RER, and applied a hydraulic disc brake to it. If you're boogying in the loose stuff and smack the clamps, not only will it have a tendency to favour the looser side, but get this- the tire with the lesser traction will actually SPIN BACKWARDS occasionally!
To lock or not to lock? Well- in the general interest of both traction and safety, I'd say lock it if your tractor is capable of more than about 10 MPH. As far as the slowing you down in a turn thing, well- that'll sharpen your driving skills, no? LOL
Also, if you lean in to the turn, you wont have to worry about it flipping (at least as much). If I ever notice im tipping out, I just lean right in. Plus it will put more weight on the inner rear tire and allow the outer one to slip more so you can turn sharper.
Also, if you lean in to the turn, you wont have to worry about it flipping (at least as much). If I ever notice im tipping out, I just lean right in. Plus it will put more weight on the inner rear tire and allow the outer one to slip more so you can turn sharper.
Mmmm, yes, and no. One of the "tricks" to better steering with a live axle (locked) is to REMOVE weight from the inside rear tire. If that tire can slip a bit, it sort of adds a wee bit of differential action, cutting down on understeer. One of the ways that this lift is accomplished is through frame flex. With a stiff or reinforced frame, proper frontend geometry becomes more critical. The proper combination of camber, caster, and KPI all work together to create a jacking effect that effectively removes weight from the inside tire.
As far as leaning goes- yes- leaning into a turn will help keep you upright. On the other hand, you don't want to apply too much weight to that inside rear. A good balance of the two? Lean FORWARD and in. Trying to get the outside tire to slip is a near futile exercise- centrifugal force and inertia already throws the weight bias to the outside. Work with it, not against it.
Subject: 
April 2nd 2013, 6:59 pm
