straight line braking with ball difs

[Tamiya Learner]

id="size6">id="blue">id="Arial Black">All my cars with ball difs seem to throw the back end out when braking is there a cure for this?[:I][][]

[fastboy]

are the cars 2 wheel drive or 4 wheel drive?

if they are 4 wheel drive do they have a one way fitted?

the braking should still be as good on ball diffs as geared diffs,a 4 wheel drive should lock all 4 wheels under hard braking unless its got a 1 way bearing fitted to the front which means you will only get braking on the rear wheels.

dave

[Tamiya Learner]

All have front oneways fitted, should I go back to normal ball difs on the front to cure this or tighten up the difs on the rear?

[terry.sc]

The back end stepping out under braking is a characteristic of using a front one way. The one way in the front means the front wheels disengage during braking, so all braking is done with the rear wheels only. To run with a one way in the front you compensate by either not nraking too much or making sure you only brake in a straight line. On the race track a front one way is used on fast, flowing tracks that do not require much braking. For a tight track with heavy braking a front diff or solid spool is used to make sure all 4 wheels are braking.

[raemin]

Always break in straight lines with a one way: a car should not flip when braking in straight lines even with a one way. If so chances are that you have a "tweaked" chassis: more grip on the left when the car turn left and vice versa. If your tires are matched and you do not have tons of traction additive in one side :9 chances are that ride height is uneven. In order identify this issue, just slightly lift (ideally with a strig attached to the center of the shock tower(*) ) the car untill the wheels starts to dettach from the ground (sorry for the poor english). Chances are that one wheel will leave the ground earlier than the over one. If so, just adjust spring preload untill both wheels behave evenly.

Hope this helps,

Raoul

(*) this will actually replicate actual mass transfer during breaking.

[raemin]

Last but not least if your chassis looks good you can try to reduce rear ride height, which will add more grip to the rear while breaking (cf. reduced mass transfer).

[Tamiya Learner]

Hi all

Thanks for all the info most enlightening

Ill start with the ride height and work through if all else fails then its back to normal ball dif at the front for my club racing

Many thanks once again

Malky

[sosidge]

Go back to the ball diff first - it'll make a much bigger difference than messing about with low ride heights. If you drop the ride height you'll just end up catching the back of the car on the track, and that will mess up the handling more.

[raemin]

quote:Originally posted by sosidge

Go back to the ball diff first - it'll make a much bigger difference

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id="quote">id="quote"> Correct but when I have two options I always go first for the cheaper one...

quote:If you drop the ride height you'll just end up catching the back of the car on the track

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id="quote">id="quote"> An alternative is to slightly raise the front / slightly lower the rear.

I would advise you to first restore factory settings and make the straight line breaking acid test: if you car fails then you have a tweaked chassis and should correct that first (I remember a small debris that was afecting suspension travel just made me mad for days before I found what was going on). Once your car breaks properly in straight line if you still experience problem (WHILe CORNERING) it is time to adjust front / rear ride heigh. If there is more than a 30% difference in front / rear ride height your in the wrong way and should look for another fix (and ultimately to remove the one way).

Many would argue against this but at least you have a plan and a few fix to try: just make one change at a time and be patient, a one way is really worth it once you get used to it, would be a pity to remove it in order to "hide" a bad setup.

[Tamiya Learner]

Hi raemin

thanks I think I will do what you said and just have the patience to work throught the pos solutions and maybe save some pennies Ha Ha after all it was the top flight club boys who advised me to go oneways for better control etc []