Three-Wheeler Without Omni Wheels?

Hi all, I'm in a bit of a bad spot here with my project. I have a modded toy car chassis as my base, and 2 big wheels on one axle to drive the car. After hours of trying to make a suspension myself, I decided to try having an omni wheel in the front of the car for turning, but the omni wheels I tried didnt work because they couldn't get enough traction with their plastic rollers, and rubber omnis are at least $20.00 a wheel, so that isn't an option. My problem is finding a way to make the darn thing turn, as cheap as possible, with an emphasis on speed. Here's a video of it without a front wheel:

https://www.youtube.com/watch?v=wCMie1hQXhE

And a pic:

I don't really know how to describe it, but I an thinking something like this:

http://www.nxtprograms.com/NXT2/mini_rover/index.html

but with that front wheel attached to a servo so it can turn. I am not sure how well this would work though, as the wheels in the back would be dragging a lot. Another option would be to build a rack and pinion using the servo you have in front. Ultimately, I think that would be a lot more complicated.

How about a ball like on this robot from Make? http://www.makershed.com/products/2wd-arduino-compatible-mobile-platform

Pauly: How about a ball like on this robot from Make? http://www.makershed.com/products/2wd-arduino-compatible-mobile-platform

The problem with that as I understand it is that he has one motor that drives both wheels on one axle. He needs control at the front of his robot to turn, so a passive ball bearing wouldn't work.

Yep, that's my biggest issue. Should've got a better chassis...

kind of low tech, but how about a big fat rubber band as tire tread?

I used a similar wheel to what is on the back buit smaller.

Do all 3 wheels to reduce the spinning of back wheels when torque is applied. (edit: It looks like your back tires are rubber)

I did this to my kids 6 volt jeep. The kind little kids can drive. The plastic wheels didn't get enough traction to drive in the grass. Even on pavement, if he drove into my legs, the jeep would stop and the tires would spin. I cut the tread off some old riding lawnmower tires, and forced them around the plastic jeep tires. the tires gripped well then. almost to the point of being dangerous. He had the traction to easily run an old lady completely over (he didn't BTW).... But he couldn't turn until I put rubber lawmower tread on the front wheels. He then had traction and could steer.

The hard part was cutting the tread off the old riding mower tires. Was a lot harder than I thought it would be. Rubber bands in the right size should be easy to find.

Why not put an ordinary wheel in front and turn it by a servo?

Archicbirch:
kind of low tech, but how about a big fat rubber band as tire tread?

I used a similar wheel to what is on the back buit smaller.

Do all 3 wheels to reduce the spinning of back wheels when torque is applied. (edit: It looks like your back tires are rubber)

I did this to my kids 6 volt jeep. The kind little kids can drive. The plastic wheels didn’t get enough traction to drive in the grass. Even on pavement, if he drove into my legs, the jeep would stop and the tires would spin. I cut the tread off some old riding lawnmower tires, and forced them around the plastic jeep tires. the tires gripped well then. almost to the point of being dangerous. He had the traction to easily run an old lady completely over (he didn’t BTW)… But he couldn’t turn until I put rubber lawmower tread on the front wheels. He then had traction and could steer.

The hard part was cutting the tread off the old riding mower tires. Was a lot harder than I thought it would be. Rubber bands in the right size should be easy to find.

This would work, but the omni wheels I was using didn’t have a big enough gap between the plastic and the rollers so I couldn’t.

nilton61: Why not put an ordinary wheel in front and turn it by a servo?

That might be what I'll have to do, the biggest issue now is getting it all set up and sturdy. Nothing I can't manage. I'll post pictures when I'm done which will be about... 2 weeks? Gotta love Hong Kong shipping...

EDIT: Nevermind actually, this car just isn't worth my trouble and money. Thanks to all who helped, but I think next time I'll stick with separate-motor wheels.