Crosskart build. Is this allowed here?

Even with all of the other cars and projects in the shop and warehouse, I've wanted to own and drive a crosskart for over a decade. I've admired them for their simplicity, performance and ability to be a Swiss Army knife and do-it-all as a toy. They can be run at an auto-x, a hillclimb, rally-x and even a track day, so one toy and so much fun. A year or so ago I was doing a bunch of late-night interwebs surfing and came across 2 different sets of plans that one can buy to build one's own crosskart. In a moment of weakness, I bought both sets! After printing out 100's of pages and sorting them in binders, they sat in a file cabinet until last week. 

 

While making an order for a bunch of rollbar tubing, I had another moment of weakness and pulled out the plans to see how much more tubing I will need for the frame jig, frame itself and building suspension arms. A few days later a truck pulls up with LOTS of steel onboard and after it was put away, I needed to seriously think whether this is something that I want to do now or in the future. Well, since I'm my own worst enemy, have no self control and a self-admitted automotive addict, I pulled out the binders and sat around for a few hours studying both sets of plans. Care to guess what happened next? Yep, it started..........

First was pulling down a bunch of square tubing and cutting everything to length. This is to build the jig which will locate the frame tubes and allow more precision than just trying to weld tubes which aren't clamped to something rigid. I built the jig on my fixture table to ensure everything is level, square, parallel and plumb. Once the jig is done and done right, I can always build another chassis if I want or need to. It came out great and verified that building the fixture table a few weeks ago was the right thing to have in the shop.

These were the first pictures of the jig.

Awesome! I've frequently fantasized about a crosskart for the same reasons as you. I'll be following with interest!

Yeah! Following

Which one of the two guides are you following? Or is this a mix and match between the two?

Single seater? twin? Which engine?

Subscribed :D

I looked at both and will "vaguely" be following the plans. The plans are more for a fun-kart using anything from a HF Predator up thru decent size motorcycle motors. Most opting for -600cc power plants and the spool rear chain drive. Mine will be a bit different. I purchased most of an old FSAE car a year or so ago and have been holding onto the parts for a future project and this seems like the right time to finally use them. I will be using both the front and rear uprights, hubs and brakes. Also, the chain-drive center section has a TRE differential which should make a HUGE difference in auto-x versus a spool/welded rear-end. The frame will be much more substantial than the plans call for as I will be adding tubes where I feel necessary. It should be a fun build and move along at a decent pace for the next few weeks. 
 

Here's a picture of all the FSAE stuff. 

Very cool.

I won't be using any of the suspension arms as they are too light duty for what I'm building. I will utilize the pedals, wheels, shift cables, clutch cable and steering wheel/quick release. 

Single seat and bigger HP I'm hoping.

lotusseven7 (Forum Supporter) said:

I won't be using any of the suspension arms as they are too light duty for what I'm building. 

I was just about to comment on this, based on the usual use cases for crosskarts that could admitedly differ from your plans - but you coverd it already :)

Yesterday was a good day. Propulsion unit secured!

lotusseven7 (Forum Supporter) said:

I won't be using any of the suspension arms as they are too light duty for what I'm building. I will utilize the pedals, wheels, shift cables, clutch cable and steering wheel/quick release. 

Good.  Depending on the skills of the FSAE team, those are disposable. 

Our lightest car we built a dozen sets of them, had them heat hardened to raise the spring rate, then after so many runs we'd swap em and cut the old ones so they couldn't be reused.  The uprights that year were also designed with a fatigue limit.

Just saying, be careful.

I'm pretty sure we'd watch a build thread of a baby if one was put up here. Come to think of it, we may have had one. 

This is freakin sweet!  There's been a pair of cross karts for sale on marketplace locally for $50k each.   Thats silly.  Looking forward to your build!

Mr_Asa said:

lotusseven7 (Forum Supporter) said:

I won't be using any of the suspension arms as they are too light duty for what I'm building. I will utilize the pedals, wheels, shift cables, clutch cable and steering wheel/quick release. 

Good.  Depending on the skills of the FSAE team, those are disposable. 

Our lightest car we built a dozen sets of them, had them heat hardened to raise the spring rate, then after so many runs we'd swap em and cut the old ones so they couldn't be reused.  The uprights that year were also designed with a fatigue limit.

Just saying, be careful.

I have the whole front-end off of a Yamaha YFZ450R(a-arms, uprights, hubs, rotors and calipers) that I bought years ago. I'll have to take a look and see if it may be a better choice for this first build attempt. 

Crosskarts are allowed at track days?

That looks easy enough!

The chain drive spool and rear axles look plenty beefy to use if they are long enough. 

And a single rear brake saves both unsprung and rotating weight, the best kind!

lotusseven7 (Forum Supporter) said:

That looks easy enough!

Wow does that look fun!

trigun7469 said:

Crosskarts are allowed at track days?

There is at least one track which allows 'em... presumably this place based on the banners and such: https://nyst.com/

Lots of chassis progress over the last few days and starting to look like something. What that something is, is questionable still.

My that has progressed quickly.  Super neat!

600cc racers when only used on paved tracks somehow evolve into these:

Great progress!  Also... shop envy.    

If it's as quick as an F600, I'll be very happy.

Mr_Asa said:

lotusseven7 (Forum Supporter) said:

I won't be using any of the suspension arms as they are too light duty for what I'm building. I will utilize the pedals, wheels, shift cables, clutch cable and steering wheel/quick release. 

Good.  Depending on the skills of the FSAE team, those are disposable. 

Our lightest car we built a dozen sets of them, had them heat hardened to raise the spring rate, then after so many runs we'd swap em and cut the old ones so they couldn't be reused.  The uprights that year were also designed with a fatigue limit.

Just saying, be careful.

The front uprights/hubs/brakes look well designed and built. Those are likely being used. The rear uprights will need some reinforcing and will also be used. The center section is going to get disassembled and gone through to see just what it is and will also be used. If I do use these pieces, I'll just have to make front and rear upper and lower a-arms and rear toe link. Wheels too of course.
 

If it's not - we riot. Love this!