Track Tac

High School Shop Kart- Steering Geometry Issues

Another thing to consider would be a freewheel hub on the brake side (rear) so that it acts like an open diff. Cons -- 1 wheel drive traction.... pros -- easier to push around and tighter turning radius (without scrub) at slow speed. If it's going to be >35mph course, that's what I'd do. [EDIT: And on a kart, 35mph will feel like 55mph if they've never been that low to the ground...]
 
I may try to keep it at 20mph for now! Well, we'll see what works, but my school district is quite lawsuite scared.
 
Ok, we made the simplest change that we could that required no drilling or irreversible procedures. Thus far it made a big difference. The turning radius was increased and the outer wheel no longer turns outward while turning. We've had the chain pop off again and I'm sure it needs to be tightened.

One thing at a time though.
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shop project! fab up a chain guide/guard for the rear sprocket.
maybe a spring loaded roller for the return side of the chain .
First everyone designs and draws them.
Chain too tight is more trouble.
 
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If your chain keeps popping off , it could be a gear or clutch issue . If you are not installing the gears correctly on the drive axle , which most have an alignment mark of sorts etched in them , then they will cause that issue . Using a lazer to align the rear sprocket with the drive sprocket also helps . Did you try and reverse your tie rods locations on the steering shaft and see what that did , as well as stacking them one top of the other with a thin shim in between the tie rod ends to see what that would do ? From the last pics I saw , I would def design or purchase a better chain guard , those chains can tear an arm up pretty good . Thank you for what you are doing , teach them well !
 
Also add a cover over the brake rotor , most sanctioning racing bodies have a rule on that . I know this is not going to be a competition machine , but safety rules should also be discussed as part of the project .
 
Only to add about brake cover.
They are intended to keep driver from contacting the rotor if the seat or strut breaks.

If looking for an example, they are generally called wolf plates. Most karting catalogs have them.
 
Lots of good suggestions above.
It appears that you seat struts do not support the back of the seat.
A real danger is that if the seat or the seat struts break (happens quite often) the seat can fall on to the brake rotor / meat saw. Serious injury is a very real possibility. I'd suggest that you mount the seat correctly and install a Wolf Plate immediately!

The chain guard is another serious issue. Here's a picture of an aluminum one that wasn't up to the task.
The chain broke and went through the chain guard and hit the driver in the bicep. It also bent the pipe to the point that it was almost touching the back of the seat. Try to imagine how that must have hurt.
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Well, We've got our steering doing MUCH better. In the long term my goal is to build more of a concession kart. Very safe, not ridiculously fast, safe... but also with certain features (like hydraulic brakes) that make it more like a real car, so kids can learn some basic principles.

I may make some sort of a cover that covers the entire rear axle, brake, and chain area.
 
Install a 2" wide flat aluminum from the rear bumper to the chain guard, that will keep the chain under the guard, nobody mentioned rear tire stagger , makes a big difference on the way it turns . Thanks for the good work
 
Jimbo said:
Lots of good suggestions above.
It appears that you seat struts do not support the back of the seat.
A real danger is that if the seat or the seat struts break (happens quite often) the seat can fall on to the brake rotor / meat saw. Serious injury is a very real possibility. I'd suggest that you mount the seat correctly and install a Wolf Plate immediately!

The chain guard is another serious issue. Here's a picture of an aluminum one that wasn't up to the task.
The chain broke and went through the chain guard and hit the driver in the bicep. It also bent the pipe to the point that it was almost touching the back of the seat. Try to imagine how that must have hurt.
Chain_guard_damage-429x571.jpg
Click to expand...

Dont believe theres an oval kart made today where there is a strut supporting the back of the seat, and been this way for years.
 
The pictures that gijoe985 posted looked to me like a plastic seat you would find in a high school classroom. It didn't look like a quality / safe racing seat. Those pictures seem to have been taken off of this post.
In my opinion (and the most important part) was the way the seat was mounted in that post looked dangerous and the brake rotor was fully exposed.
The intent of my original post was to point out what i felt was unsafe.
I agree that it would be abnormal for the rear seat struts to be mounted to the back of the seat but a "normal" go kart racing seat is usually strong enough to support the driver when the seat struts are mounted in their "normal position"
I'll try to be more accurate in the future.
 
So, the seat was a karting seat from Ebay. Or so I was told. It's definitely not a classroom seat. Those I do know well. ;)

But it is only held on with HD zip ties. Better than duct tape, right?

One of my students surprised me with his efforts to make a wolf plate. It's better than I expected.

I don't know why my pictured are gone? I put them on photobucket to share.

Lastly, though we do want to keep safe, that is a high priority, also know that we will not be racing this on a full sized track. If we ever build it, it will be a small, under 30mph, track around our shop.

I may need to swap out the slicks for some treaded tires. We've talked about doing a "rallycross" style track. (we have a lot of gravel around the shop, much less pavement outside. It could be fun... )
 
Zip ties for seat mounting?!! It should be a 5/16" bolt minimum, with a fender washer on each side of the seat to distribute force, and double nut or nylock on the seat strut side. They also make conical washers for the drivers' side that increase comfort (at least compared to an exposed bolt head.) The way the seat is mounted is the most important aspect of handling in a kart.

I'm sorry, but.....Zip ties? Parents entrust you with teaching their children about power tools and you thought ZIP TIES was a good and safe seat solution? C'mon man.... I presume you're a real shop teacher and not an internet troll, so I don't want to sound too critical, but in racing, experience is a harsh teacher. And sometimes you don't get 2nd chances, nor will your students. I'd hate to see something bad happen that was avoidable by common sense. I'd evaluate every area for potential injury, and definitely get in touch with Mark Bergfelt, preferably by phone. Good luck as your project grows...
 
Ted Hamilton said:
Zip ties for seat mounting?!! It should be a 5/16" bolt minimum, with a fender washer on each side of the seat to distribute force, and double nut or nylock on the seat strut side. They also make conical washers for the drivers' side that increase comfort (at least compared to an exposed bolt head.) The way the seat is mounted is the most important aspect of handling in a kart.

I'm sorry, but.....Zip ties? Parents entrust you with teaching their children about power tools and you thought ZIP TIES was a good and safe seat solution? C'mon man.... I presume you're a real shop teacher and not an internet troll, so I don't want to sound too critical, but in racing, experience is a harsh teacher. And sometimes you don't get 2nd chances, nor will your students. I'd hate to see something bad happen that was avoidable by common sense. I'd evaluate every area for potential injury, and definitely get in touch with Mark Bergfelt, preferably by phone. Good luck as your project grows...
Click to expand...


Yes, but they're "HD zip ties." ;)
The idea of running the kart in a gravel parking lot should have raised more than a few eyebrows as well.
Unless you're going to run full enclosed fenders on this kart, expect a trip or two to the nurse's station for an aspirin, and a phone call from the parents shortly thereafter.

As much as I love the idea of introducing kids/teens to karting and working with them as part of a school project/class, I think that you are in way over your head as their instructor, and need some on-sight help rather than just from an internet board.
You've got a lot to learn, but safety should always be your primary concern (and that of your principal, super, and school board members who have got to be cringing at the sound of their insurance underwriter.)
 
Gijoe985
Be aware that what was stated are facts that are relevant to your situation.
Safety should be your first consideration.
The fact someone else did it does not make it correct.
Name calling is not going to further your cause.
It is actually noncompliant with the rules of this site.
 
There's a fine balance on the internet between calling someone out in a manner intended to be helpful, and simply coming across as a know-it-all. I hope I didn't cross over that line. But now that I have a 6 year old in K, the reality of school safety is a little more pressing. I guess as a teacher, you have a hard balancing act between encouraging creativity and shielding from harm. I don't claim to know that balance, and I'm more risk tolerant than most... But I'm also keenly aware of the physics involved... This is a good site to gain advice from, and I think 98% of the people here are well-intentioned and simply trying to be helpful. I hope you keep posting here and finding the answers you need. Cheers, ~Ted
 
Gijoe985
I'm sure you know that there are high schools that have "shop classes" that build various types of actual race cars. I'm not sure who the drivers are but i'll bet it's not the students. I respect you for what you are trying to do! I don't want to come across as if i'm preaching. It sounds to me like you are trying to do things right. I respect you for what you are trying to do. You have a tough job. Best of luck.
Jim.
 
Ok, I guess I missed the name calling or whatever else happened in the thread. If I came across as offensive, then please understand that I am only trying to help you (Gijoe985) understand better. As I mentioned earlier in this thread, we have a local high school teacher who has been working with Margay and Briggs to put together 10 karts for their shop/tech. class. I'd suggest that you contact others (possibly in your area) who are doing something similar for some guidance.
I think we all appreciate your intentions, and to a point, I am guessing that most of us our envious that we didn't have an opportunity to participate in something like this in school as a teenager.
I don't know how far Jimbo is from your school, but he'd be an excellent mentor/advisor to have take a look at your program and help you out. I suspect his schedule is pretty full this time of the year (most engine builders are) but he's a great source of information for you to glean from. Give him a call and see what you guys can work out, even if it's just a one time visit.

Sure, this site is a wealth of information, but I am still convinced that you need some on-sight help to better identify some issues that go beyond those seen in the photos in post #23: zip tied flimsy plastic seat, seat strut location, no wolf plate, no chain guard, axle extended beyond the wheel, etc, etc.
I wish you success and safety on your venture.
 
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