Brainstorming for new build.

[JWales]

Hello! I'm new but have lurked around for awhile. I'm trying to get a few ideas together so I know where this thing is headed. I need to keep it simple and cheap.

I'm looking to do something similar to this:

My first question is bump steer, will it be a big problem on something this small? If so what do I need know to minimize it? I can't imagine the a-arms being any longer than 8" - 10", I will probably use a lower a-arm and upper single with shock that passes through. It doesn't look like it would have more than 6" of travel if that.

Next question, this thing is probably going to be about 14" - 15" wide. I was thinking to widen the rear frame out close to the axles. I plan on using 1" solid axle but i'm worried about it bending. Is it a good idea to widen it so my bearings are close to the rear wheels or am I being over cautious? I could go 14" 15" wide from front to rear like this go did.

My goal is a simple off-road kart. I need to keep cost down and utilize what I have as much as possible. I have some scrap metal, plenty of 1-1/4" square tube. I have some 6" - 10" saw blades that are bad, could these be used for things like disc brakes or sprockets. I just want to throw a few ideas around and gain some direction on my project.

Thanks!

 

[qtband]

Welcome to the forum!
I would think that the wider kart is more stable and will resist rollovers. As for the saw blade, they might be a little thin for disc brakes. I'm sure others will respond with some opinions.

 

[landuse]

Welcome to the forum

It is always better to have your axle bearings as close to the wheels as possible to prevent bending or snapping of the axle. I suppose it all depends on what type of riding you are going to do. Offroad, you will need bearings as close as you can get. On road, maybe not so much.

 

[klicky96]

Unless the teeth are completely cut off of the blades then I wouldn't use them. but, if you do cut them off and the disc is not flimsy, then I'd go through with it but test it first. And with the frame, extending the reared would be safer and wouldn't require much work to do. I would do it. What size engine and tires are you planning to put on this?

 

[r_chez_08]

I am pretty sure you can get brake discs for around $4 at bmikarts. Not worth skimping on IMO. And the saw blades will not work for sprockets.
BTW, welcome

 

[christeeezy]

I bought one of these rotors from BMI:

http://www.bmikarts.com/item/8-Brake-Rotor---Black-05706B-6557

And the quality is really great, especially considering the price!

 

[JWales]

Thanks for the welcome.
I planed on tack welding two blades together and shaping them into sprockets or disc. Obviously i'd cut off the teeth Thanks for the link. The disc are cheap, and i'd probably order it. Most of this stuff is pretty cheap. I'm thinking if I bought every component it would get pricey fast. So i'm really looking to make anything I can with in reason. Time is one thing I have.

To answer some of your questions: I plan on using anywhere from a 6 to 9hp engine. The 1" solid axle listed on bmi. I was looking at using either 4 wheeler rear tires/rims or something like this:
http://www.bmikarts.com/item/16x8-7-Rear-Tire--Rim-260042-6617

The kart that I'm basing my design off of seems to be using at least a 36" axle. I would like to use a 36" - 40" axle. I will base the size on how wide the front has to be.
Here is a rough sketch.

The idea behind keeping the frame skinny is simplicity. If I make it wide, i'll have to put contour it inward in the front so i can have room for the long a frames. I was toying around with the idea of stoping the frame before the front end and just coming out with a single bar on the bottom for the A's to reduce bumpsteer. I'm kinda worried about it, but don't know if it will even matter on something like this.
Frontend change:

The problem I have with doing a front end like this, it makes the kart longer. I wanted to put the pedals in front of the front wheels to keep the wheel base some what square and small. I'd be nice to be able to transport this thing with out a trailer lol!

Thanks again for all the ideas, keep them coming please!

And.. I will be using this off road, mainly in fields and dirt paths.