Frame Materials Strength

[jamyers]

I'm planning on building a mini "Bucket T" roadster, using the engine, suspension, and steering from an old Chinese atv and a bunch of odds/ends laying around the shop. It'll have a ladder frame, a fake 'radiator' that's actually the front shock upper mounts, then a clone of a Honda Rebel 250cc twin-cylinder engine, then the body (an oversized "Cozy Coupe"), then the rear axle (which has a differential and reverse box.

By my layout drawings, I'm looking at a 7-foot wheelbase, with independent front suspension and the rear axle bolted solid to the frame.

Question is, will 2 lengths of 1" x 2" steel rectangular tubing be strong enough? Or maybe 3" or 4"

 

[jamyers]

No ideas? I've looked all over the interwebs, but can't find anything showing strength of materials info that isn't engineer-greek-speak.

 

[mckutzy]

On end... it should be plenty....
Whats the thickness??

 

[jamyers]

.075", looks like 14 gauge. ASTM A513 is printed on it.

 

[itsid]

tough question.

short answer: sure!
long answer: depends on the cross bracing and exact layout as well as weight and intended use

you can find calculators on the internet to calculate bending forces and charts to compare those to,
but frankly.. in this case eyeballing it will do just fine.

take a look at your everyday yard kart see how they're made (roughly 1" round tube with 5ft wheelbase)
and you'll certainly can guess your way from there

'sid

 

[Kartorbust]

A genuine Honda CMX250 (234cc) is about 16hp and 13.28lb/ft of torque. Engine weighs about 86lbs (not sure if this is dressed or long block). 1" tubing should be enough. The size of tubing you are looking at will be more than plenty. Though you could get away with 1 1/4" square tube and 14ga thick and be plenty strong.