222 drive train issues

[Alfredo Campanini]

Hi Patrick,
I agree that the suspension travel can be not enough, but I think that the main responsible is the central diff.
The greater part of the off road vehicles has the possibility to block the central diff, because it is the first weak point of the transmission.
The solution would be a blocking central differential, but I think that it is very difficult to make in 1/6 scale.
If somebody know how it work .....

[Patrick O'Donnell]

Hello Ad and Alfredo,
Yes I understand about having the centre diff fixed, but if all the wheels could be kept on the ground then I think that the diffing-out problem will be much reduced. If the suspension could be made just a little bit softer I think all the wheels would stand a better chance of keeping in contact with the ground.
I seem to remember Vince Abbott saying that he added alot of extra ballast to his 222? and I think this would in effect make the suspension softer.

[Alfredo Campanini]

You are right Patrick,
a good performance start from suspension.
Me too I remember that Vince (someone says that he is in Bahamas, for a long time) told he added an extra ballast of about 6 Kg.
But if one of our problems is the hard springs, maybe Mark is able to offer an option of softer springs.

[Ad Wouterse]

Hello Afredo,

There are two ways that are most used to block differentials.
The first way is welding. On both outgoing bevel gears some of the spaces between the "teeth"are filled with welding material. On 2 or 4 spots (depending on the number of spin gears, in our case 4) the "teeth" remain untouched. Here you can find a series of pitures showing the procedure http://www.island4x4.com/4x4tech/axle/weldeddiff1/ .

The second way is the use of a "spool" . Basically this is a bracket with 2 or 4 extensions which is pushed over the spin gears, thus creating the same effect as the welding. Unfortunately I have no picture at hand at this moment.

As Mark mentioned earlier, blocking a diff will create strong loads on the drive train under certain driving conditions (e.g. high speed sharp turns). Although such a condition is unlikely to occur with a 222, this matter kept me busy. Therefore I decided to figure out a way to block the centre diff, while maintaining a possiblity for the diff to slip under extreme loads.
The basic idea is a mix of the clutch of a car and the spring loaded principle of a servo saver. I have made several drawings and I am quite positive that it might work. The problem I am facing now is to find the right material to build a prototype in 1:6.
I will keep you posted on my progress.

[Alvin McCall]

I am sure there are many ways to help or cure the wheel hop problem , the silicone fluid thickness is one. If a wheel hops or lifts then keeping power to the ones on the ground will drive it over or out of the wheel lift issue and you will not have to redesign the suspension.

[Ad Wouterse]

Hello Alvin,

Keeping power to the wheels on the ground is what we are trying to achieve. Now all power goes to the wheel that is lifted.

[Allan Richards]

It sounds to me that one has to loose traction on only one wheel for power to be lost to all the remaining wheels. Removing or blocking the centre diff would mean that at least two wheels, one on the front axle and one on the rear axle, would have to loose traction to stop the vehicle. Thus I would say that locking the centre diff could cure 90% of the problem.

I feel that sticking loads of ballast in the vehicle may not be the best way to go as this will put more and continuous stress on the drive train and drain battery life. I would only consider doing this if the vehicle is clearly under scale weight and is bouncing all over the place and not looking right on the ground. From what I've seen the 22 does not behave in this way.

[Patrick O'Donnell]

Allan,
Yes I agree about the not adding of extra ballast as I think that the sdkfz 222 is already the heaviest armoured vehicle for its size.

[Jan_Donadoni]

Hello, just wondering. If actually the 222 is mounting the same differential of the Hobao Hyper7-8, than it means that it is working with a differential built for a 4-5kg car. So using "tuned" differentials for the same model should not being too destructive for the mechanism. After all we would use it on a heavier vehicle, but going much slower than the r-c off road car. Also we would avoid continuos stress in accelerating and decelarating, ad all the jumps associated with buggy racing.

[Raymond Glover]

Hi - I was wondering if anyone has locked all the differentials on the 222, and if it caused any malfunctions?

Ray Glover
Killeen/Ft Hood TX USA