used chassis scrape wear - what's too much?

S

sekart

New member
Greetings all. I recently bought a kart from someone and I just noticed there has been some scraping on the bottom of the frame / chassis right in the middle (saddle or waist) under where you sit like I'm sure happens to all karts. I'm curious though at what point should one be concerned of excessive scraping or wear?

What is the typical or minimum ride height of the chassis to the ground where you sit?


On a side note, I do completely trust the people I bought it from. There's no way they sold me junk. This is not why I'm asking these questions. I'm just trying to understand what the general consensus is and then try to find ways of protecting it more than it has been at the point's I'm referring too.

Thanks!
 
You didn't say if it was raced on dirt or asphalt. Around here our dirt tracks are so bad, that the bottom of the chassis gets beat up pretty good. A couple of the asphalt tracks we run at the kart hits the track if you go low in spots or from running off the top of the track into the grass.
 
Get a set of calipers and measure the diameter of the tube where the scraping is. Determine what the wall thickness of the tubing is. The thinner the tube wall gets, the easier it is to bend, and a course if it bends, it's even close to the ground and scrapes more. What's acceptable is up to you and your ability to drive the kart. A good welder, (I'm an ex welder so I know) could form a sheet-metal piece to weld over it.

The consequences of the scraping is going to depend on the wall thickness of the tubing. I had a friend whose euro Sprint kart with wear like that and his was almost all the way through. He hadn't noticed any difference in handling. The change in handling is such a slow process that he just got used to it and adjusted his technique in his driving. He had won races when the car was new and was still winning races when he discovered the wear.
 
Kj26 said:
You didn't say if it was raced on dirt or asphalt. Around here our dirt tracks are so bad, that the bottom of the chassis gets beat up pretty good. A couple of the asphalt tracks we run at the kart hits the track if you go low in spots or from running off the top of the track into the grass.
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This kart has only been raced on asphalt.
 
We call that phenomenon "flat spotting", and usually I try to avoid purchases where the flat spot it wider than 1/4". They now make nylon rub guards, or you can use some heater hose and hose clamps....just be sure THOSE don't wear off. :) I haven't seen too many courses where going over the curbing was the fastest, but there are some. Columbiana, OH was fastest when you hung your outside tires on the track edge (legally inside the curb) and let centripetal force hang the whole rest of the kart (and you) over the curb and grassy outfield...basically a controlled bicycling....
 
Columbiana, OH, when did you race there Ted?

What turn are your referring too? The only curb I can think about is what we use to call the bricks. About the only thing I can brag about is to this day we(my son) have/has taking some credit for his doing, the senior medium record there in boxstock. ... :)
 
alvin l nunley said:
Get a set of calipers and measure the diameter of the tube where the scraping is. Determine what the wall thickness of the tubing is. The thinner the tube wall gets, the easier it is to bend, and a course if it bends, it's even close to the ground and scrapes more. What's acceptable is up to you and your ability to drive the kart. A good welder, (I'm an ex welder so I know) could form a sheet-metal piece to weld over it.

The consequences of the scraping is going to depend on the wall thickness of the tubing. I had a friend whose euro Sprint kart with wear like that and his was almost all the way through. He hadn't noticed any difference in handling. The change in handling is such a slow process that he just got used to it and adjusted his technique in his driving. He had won races when the car was new and was still winning races when he discovered the wear.
Click to expand...

The easiest way to do it instead sheet metal would be to lay a few beads over the scraped area to actually fill it in then grind it into shape, that way it maintains the strength of the tubing instead of patching over it. Once that is done he should be able to get another 10 years or so out of it before running into this problem again, without weakening the frame rails or just throwing a patch over it
 
paulkish said:
Columbiana, OH, when did you race there Ted? What turn are your referring too? The only curb I can think about is what we use to call the bricks. About the only thing I can brag about is to this day we(my son) have/has taking some credit for his doing, the senior medium record there in boxstock. ... :)
Click to expand...

Paul -- I only tested there with my buddy, Robin Bank, who did race there -- Formula K and Formula A, 135 and 100cc karts. The turn in question is the right hander after the double left turn 1-2 complex that leads down to the "back section."

I tested there in 2000-2001, he raced there in the early 90's.
 
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