no steering = wreck

[my65stang]

http://i701.photobucket.com/albums/ww11/my65stang/wreck002.jpg

Here it is 6.5 hp, custom exhaust, clutch, 48 tooth rear sprocket,



I took it for a maden voyage. I couldnt wait to get all the non important stuff hooked up such as throttle and brakes. i just used the turtle rabbit lever to control the speed. It was a hell of a lot faster then i thought it would be. I'd guess 30mph. But what i found out trying to make my first turn. it didnt turn i hit the curb at 10-15mph. The front end just hydo-planed, the front tires would'nt bite and the pavement was dry. It would just push the front tires.


Why?
Not enough weight in front?
Front to long?
Not enough caster?

My plan is to shorten the front 2-3" to add more front nose weight. add more caster. I also pull the 6.5hp and i put in the old 3.5hp. way to fast for my kids to drive.

what else should i try?

besides throttle control and brakes.


http://i701.photobucket.com/albums/ww11/my65stang/wreck004.jpg

[Fudd]

I suspect it was the angle of the dangle. In other words your steering column is at too much of a rake where the tie rods connect. I'm no suspension expert but my guess is with the set up you have you need a differential type rear axle. Try doing a google and type in ackerman principle. The ackerman is a formula taken from the center of the rear axle and an imaginary line (use string) that goes out to each spindle. I think too that your tie rods need to be paralell to the front axle. hope this helps. Other than that it is a cool ride.

[my65stang]

So shortening the front end and the wheel base should help?

[my65stang]

So if i draw a V from the center of the rear axle forward, those lines should line up with my spindles?

How do you get them to line up that way?
find the angle then weld them?

i'll check the ackerman angle tomorrow.

[Snakester]

Hey Stang, Fudd pretty much nailed your problem...The live axle on a short wheelbase like this will make it feel like the front wheels just won't turn. Kinda like a Bulldozer...A differential axle will solve that. You do need to keep the tie rods parallel to the front axle like Fudd said...In your set up , with the end of the steering shaft behind the front axle you are not getting the same turn on the wheels as you are on the steering wheel. When I was Racing Karts and building Kart Chassis , I always mounted the lower end of the steering on the front axle or just behind the axle to get it in line with the spindles , and the pitman arm worked like the steering arms on the spindles. Check out TS Racing's Site and look at the Designs of the high end frames...Notice that the front axles all have a bend to the rear...This is to help high speed control...Some are longer than others. You can learn a lot from just studying these frame designs. Good Luck with your project!:cheers: Snakester...Don't forget a KILL SWITCH !!!

[my65stang]

I see a lot of karts or bar stool racer built with live axles. I really don't want to spend a hundred bucks on a new axle setup.

So if i shorten the front and move the front axle back in line more with the steering so my tie-rods run parallel. And re-weld the front spindles slightly back at angle, try to do the ackerman principle, how much would this help?

Do i need to widen the front axle to the width of the rear? Right now the front end is 3" narrower then the rear.

I also pulled the 6.5hp out and I'm putting the 3.5 briggs in its place to slow it down (this is suppose to be for my kids) I'll build my self something else with the 6.5hp.

this is definitely a learning process

[CritterBuddy]

You guys are right on with what you are suggesting but there is one other factor you also have to consider. Because of the design of the vehicle there is not enough weight on the front end. By all means you can do everything that has been suggested and it will help but the lack of weight on the front end will still be a problem. The easiest fix is to simply remove the square key from one of the rear wheels and make it a dead axle drive (one wheel drive).

[RED]

My 2p...........2 things at fault..Steering column angle to the tie rods.Also the live rearend. The rearend can be relatively easily fixed. Leave 1 wheel driving ,and make the opposite hub freewheel. I do this on all my wagons ,and havent had a problem. Ive used 2 methods..1 is to build a hub with bushes in it ,so that it rotates freely ,OR 2, just build a hub using a steel tube that fits snugly over the axle,and run it metal to metal with poss a grease nipple or maybe a oil hole built in .When you think about it ,for the use that these things get,and the amount of times the free hub will rotate independantly of the axle ,it should be OK.Its lasted a long time on one of my wagons ,with no sign of excesive wear.Hope this helps.
BTW .......Disclaimer to all the above..................
and PS DONT get too impatient about a test run before brakes AND steering are checked on the bench ,AND at slow speeds!!
PPS I dont think just removing the key way is a good idea,as it looks like your Kart hubs are poss aluminium (easy wear) and the wheel offset is quite high,leading to a lot of leverage /wear. Tey to use a hub which allows the wheel to be mounted more central to it ,therefore spreading out the load...once again ,just my cautious 2p...!

[c.schulz]

I would move the axle back a couple inches so that the tie rod is at an equal length to pitman arm(Even for and aft). Then change the angle of the king pin to 10* so that you will not get so much sliding from the front tire. With more king pin angle it will make the tire bite harder but your steering will be a lttle harder also.
If you go with the removed key on the axle be sure to have axle clamps on both sides of the loose wheel and give it some grease as to not gaulle the surfaces.

Chris
http://img.photobucket.com/albums/v347/cschulz/wreck004.jpg
http://img.photobucket.com/albums/v347/cschulz/aa.jpg

[c.schulz]

Also you may want to add a jackshaft to slow the gearing down. This what I did with my kids go kart. The slowest gearing I could get w/o a j/shaft calculated out at 17MPH. Add the jack shaft and it went down to 7mph. After they were good drivers then I added more gear and speed.
Chris
http://www.compgoparts.com/TechnicalResources/

[my65stang]

well i cut the front end and shortened it. the front axle now sits directly in front of the steering shaft. next is to weld the front spindles back on tilted back more.
I bought my front spindles as a complete kit. So to get a correct ackerman angle ill have to cut were the tie-rod mounts are welded on and tweak them to angle in more.?????????

[c.schulz]

All sounds good.

Chris

[Ironfist104]

Just get one end of yur axle machined down to fit a front wheel hub....works like majik.

[c.schulz]

Just get one end of yur axle machined down to fit a front wheel hub....works like majik.3

Thats a realy good idea. Surprised know one has mentioned it before.:cheers:


Chris

[Ironfist104]

actually it was mentioned....here

http://barflyracers.com/showthread.php?t=670&page=2

[my65stang]

The front axle was moved back to the steering shaft 4".
the spindles were tilted back.
the tierods shortened and now run more parrallel
i cut were the tie rod mounts to the spindles and re welded them at more of a angle.
i widened the front end 1"
i switched to a smaller motor (for now)
So the back overall width is 33" wide and the front is 32" wide and axle to axle is now 33".
http://i701.photobucket.com/albums/ww11/my65stang/newfrt002.jpg
I like the idea of running a 5/8" front wheel hub on the rear axle. that will be next if the above doesnt work.
http://i701.photobucket.com/albums/ww11/my65stang/newfrt001.jpg
Well these pics dont show the angle very well. try again later.

[my65stang]

:angry: Well today i tried it out with the old 3hp briggs with a reducer. Didn't work not enough rpms with the reducer to engage the clutch. (someone told me it wouldn't work but i had to try to know for sure) So i put the 6.5 hp clone motor back in. Still no throtle or brakes. Well after all the changes to the front steering it maybe improved it 10-20%. So then i tried removing the key way to one of the rear wheels, and i zip tied a smaller key way to keep the wheel from moving to much. that improved the steering probally 50% at slow speeds, i still have to slow way down and lean forward to get the front tires to grab, but once they do it turns in about a 6' radius.
So back to the drawing board any other ideas?
:cussing: :cussing:

[RED]

Have I got this wrong???...........Using a front hub on one end of the rear axle = machine down the axle(to 17mm?) or are there larger id bearings on some fronts? If axle is machined to 17mm,wont the smaller diam be a lot weaker ,and therefore try to bend,considering the weight of the driver is at the backend? We machined the axle to fit rear wheels with a small diam bearing on a Kart we built at work. Had loads of probs with the ends bending .

[RED]

Stang ...try more camber on the fronts.

[Ironfist104]

Have I got this wrong???...........Using a front hub on one end of the rear axle = machine down the axle(to 17mm?) or are there larger id bearings on some fronts? If axle is machined to 17mm,wont the smaller diam be a lot weaker ,and therefore try to bend,considering the weight of the driver is at the backend? We machined the axle to fit rear wheels with a small diam bearing on a Kart we built at work. Had loads of probs with the ends bending .

K well you could go to you local bearing shop and find one with a bigger center....

But I dont think it will make too much a difference you would have to hit something prettty hard to bend that...

? 17mm= 5/8"....

[my65stang]

http://i701.photobucket.com/albums/ww11/my65stang/abc001.jpg
http://i701.photobucket.com/albums/ww11/my65stang/abc002.jpg

Well at slow speeds steering is okay, but going fast its hard to keep it straight. (This is with one rear key removed )

[Ironfist104]

If it har to control at hight speed It ither ur alignment is of toe in toe out or You dont have enough caster. Caster is a major thing and just by looking at you photos you dont have very much of it. On my wagon I havejust a bit over 1/8" of toe in and 14 deg. of caster and 0 ackerman. On my barstool I have 1/8" toe in, 15 deg of caster I can actually let go of the steering wheel and it drives strait and again 0 ackerman.

[my65stang]

http://i701.photobucket.com/albums/ww11/my65stang/a001.jpg?t=1235102892

Well i found another motor a 3hp briggs for $35. i installed it and it runs great. i put the key back in the rear axle, so both wheels are turning again.

It handles a little better with the smaller motor due to less torq.

[Fudd]

After viewing you original photo your problem is way to much weight to the rear. Just for fun take some ratchet straps and secure one or two cinder blocks on the front. Something else and old cart racer told me to do (and it worked) was instead of toe in go with a toe out. and for god sake get some brakes on that baby. Keep us posted . Your gettin close!:cool_dude:

[Ironfist104]

Have a look at my frame in the pics I posted . You'll see the I pushed back my rear axle. so I'm sitting in front of it not on top...thats a big thing too just like the previous guy said all yur weight is on or behind u'r rear axle...that why I didn't go with the wagon works frame it designed sorta like yours.... Anyway dont like to say this but ya might have to start your drivetrain over...:bigcry: :bigcry:

Here's Mine....

http://barflyracers.com/showthread.php?t=670

[koolaid89]

You could also opt for shorter front tires or taller rears to build in some chassis rake and move weight forward.