Diff rear axle

[CobraII351]

I bought a older kart for my daughter. I pulled the old very small unknown motor (doesn't look like any Briggs or Tec motor I've ever seen). It is currently 1 wheel spin after the addition of the HF clone. I'm thinking about a rear diff from Northern Tool has anyone used one of these and with what kind of results? I've seen a mentiion of people using dual brakes on the axle after the swap, is that recommended or necessary? What about a single disk on the diff housing? Any input is appreciated.

Thanks,
Tim

 

[frederic]

Once you add a differential, you essentially have two axles and applying the brake on one axle only allows the engine to drive the other axle without issue, encouraging a spin condition as the still-driven wheel tries to rotate the kart around the braked wheel (pivot).

On a low powered kart the result might be a strong pull to the side that's braked, on a powerful kart that might result in a spinout and maybe a flip-over if the kart "trips" while trying to pivot around the braked wheel.

If you put the brake on the differential itself you still have the same condition because one axle is tied to the housing, and one is tied to the spider gears inside so you'd be braking only the wheel that's connected to the axle that's connected to the housing.

Configuring two brakes is not a big deal... if they're hydraulic you can tap the connection between the brake hose and the caliper and install a "T" fitting, then run another brake hose to the new caliper on the other side. If they're cable-driven, the easiest way to facilitate this is to run a new brake cable from the new caliper to the brake pedal so the pedal actuates both cables simultaniously. You'll have to adjust the tension of both cables so that both brakes do their job as equally as possible for even braking.

 

[CobraII351]

Ok, I understand what you are getting at with the single brake on the Diff housing. It makes sense, I just wasn't thinking about the possibility of the two wheels having different traction. I think an easy way to do a dual cable system is similar to the way a lot of parking brake setups are done on cars. With one long "U" cable pulled at the center that is a better way of getting the tension equal on each side. Just a thought.

Tim

 

[frederic]

It makes sense, I just wasn't thinking about the possibility of the two wheels having different traction.

I figured as much and this possibility may be very unlikely, but on the odd chance it might happen safer is better than sorry.

You would feel horrible if your daughter flipped over, even if she's unharmed and AOK. Trust me, I'm a father also.

You could tie the two brake cables together with a bracket to another cable that is attached to the brake pedal - certainly there's nothing wrong with that however my suggestion would require less fiddly bits and maybe as difficult as drilling a second hole in the brake pedal's cable mount. Maybe not, obviously you can see better what you have to work with.

I just try to avoid fiddly stuff as much as possible when reliability is highly important, as would be the case with brakes.

 

[CobraII351]

Yeah I know what you mean about the safety thing. I'm trying to figure out how and where to put more cage under the fiberglass body.

The brake "Fiddly stuff" depends on how you look at it. 3 cables, 3 pieces of conduit with 6 ends, 3 possible adjustment spots, and the associated hardware. Or 1 cable with 2 ends, 2 condiuts & 1 adjustment location and the hardware. It's all how you look at it I guess. But i do appriciate your input.

Right now the upgrades are all in the planning stages. Getting permission from "She Who must be obeyed" to make the purchases is the first step. Or to just make lots of smaller purchases. either way I'll get the work done slowly. I have time to get things right until the little girl can even reach the pedals. My big *** doesn't fit at all with the body on. That just for pretty and and the main reason for buying the cart is that it matches my car.

Thanks,
Tim