Viper STX live axle conversion / Help

[fodio]

Hi everyone! I'm new in this forum and I need your help.

I built a Viper STX using the MXK.COM plan. It is single drive with a sprocket/drum brake, so only one tyre brakes and it is a real safety issue.

I use the go kart in the back yard and driveway. In the grass the traction is terrible (as expected for a single drive).

I think it should be converted to live axle, it will fix the traction in the grass (I hope it won't impact too much in hard surfaces) and also will solve the braking issue.

It has Azusa Tri Star 6" wheels with 5/8 bearings, so I need to find the best way to connect them to live axle. Does anyone know about a hub / flanger for this purpose?

My initial plan is to buy a 1" rod (1020 steel) and take it to a precision shop for key way and threads. I'll use pillow block bearing to attach the axle to the chassis.

I would like to use the sprocket/drum brake (some sort of flanger with key way will be required)

I live in Costa Rica, so don't I have good access to parts at decent prices.

As you can see I need your help. I'll really appreciate your ideas, advice and honest opinions to convert the Viper STX to live axle.

Kind regards,


Felipe.

 

[Russ2251]

Good little yard kart. Had mine several years now.
Weighs only 98lbs. total.
Dead axle is part of the fun. Can make square turns!

 

[rmm727]

They sell Tri Stars that are for 1" axles.

 

[fodio]

I ordered some parts from AZUSA, they should arrive to Costa Rica by Sep 20...

I'll try to post some before/after pictures...

 

[OzFab]

I think it should be converted to live axle, it will fix the traction in the grass (I hope it won't impact too much in hard surfaces) and also will solve the braking issue.

You should be more worried that a live axle conversion will have a massive impact on the steering

 

[zbuck]

Most 1" 1020 round wether cold/hot rolled will not be to size (O.D.), it will under. Best to buy 1 1/8 and have it turned to 1". Also you will have to know your keyway size. I also noticed the 5/8,s bearing size, are those front or rear wheels?

 

[landuse]

Most 1" 1020 round wether cold/hot rolled will not be to size (O.D.), it will under. Best to buy 1 1/8 and have it turned to 1". Also you will have to know your keyway size. I also noticed the 5/8,s bearing size, are those front or rear wheels?

What?

 

[rmm727]

^ This

hot rolled will be bigger than 1" due to mill scale. cold rolled should be about right on 1". Given the tolerances of Azusa parts, I wouldn't be surprised if either one fit. Keyway for 1" is 1/4"

 

[fodio]

You should be more worried that a live axle conversion will have a massive impact on the steering

Yes, I know but I use the kart in the back yard and it gets stucked in the grass and gravel. I hope an improvement in traction.

I'll post results when the parts arrive.

 

[fodio]

Most 1" 1020 round wether cold/hot rolled will not be to size (O.D.), it will under. Best to buy 1 1/8 and have it turned to 1". Also you will have to know your keyway size. I also noticed the 5/8,s bearing size, are those front or rear wheels?

The 4 wheels are 5/8" with bearings. I ordered from AZUSA parts to convert 2 of them to live axle (half wheel with keyway and 3/4 bearing), a sprocket hub and 1" axle. Parts should arrive by Sep 22. I'll buy pillow block bearing here in Costa Rica.

I'll post pictures before and after the modification.

 

[fodio]

^ This

hot rolled will be bigger than 1" due to mill scale. cold rolled should be about right on 1". Given the tolerances of Azusa parts, I wouldn't be surprised if either one fit. Keyway for 1" is 1/4"

It is cheaper to buy the axle from AZUSA than 1020 + precision shop charges (at least here in Costa Rica)

 

[OzFab]

Helpful Tip: See the button next to the "Quote" button, the one with "+ on it? That's the multiquote button; when you want to quote a number of posts, use that on all but the last post (at which point you use the "Quote" button) as opposed to making 3 or 4 consecutive posts...

 

[rmm727]

It is cheaper to buy the axle from AZUSA than 1020 + precision shop charges (at least here in Costa Rica)

I believe it.

 

[Poboy kartman]

Yes, I know but I use the kart in the back yard and it gets stucked in the grass and gravel. I hope an improvement in traction.

I'll post results when the parts arrive.

Ummmmmm....yeah. ...why didn't you just post that up in the first place. .....you don't need a new axle......you need new tires.......

I hope you have a big backyard. .......

ARRRGH.......

 

[fodio]

Ummmmmm....yeah. ...why didn't you just post that up in the first place. .....you don't need a new axle......you need new tires.......

I hope you have a big backyard. .......

ARRRGH.......

Not clear with your comment. As far as I know my initial post/question gives enough details about the traction and braking issues.

I'm really interested in learning as much as possible about building karts. Do you think that bigger tires will solve the breaking/traction issue? If so, could you please explain why?

 

[OzFab]

Do you think that bigger tires will solve the breaking/traction issue? If so, could you please explain why?

Using a larger tyre will affect the drive ratio so, you will end up with less initial torque, meaning, it will be less likely to break traction...

Likewise, the larger size of the tyre will also affect braking... for the opposite reason: A larger tyre will be more difficult for the brakes to stop &, therefore, will be less likely to "lock up"; be aware that, as a result, on hard surfaces, braking will take a bit longer...

 

[landuse]

What he said /\

 

[fodio]

Using a larger tyre will affect the drive ratio so, you will end up with less initial torque, meaning, it will be less likely to break traction...

Likewise, the larger size of the tyre will also affect braking... for the opposite reason: A larger tyre will be more difficult for the brakes to stop &, therefore, will be less likely to "lock up"; be aware that, as a result, on hard surfaces, braking will take a bit longer...

Thanks for the explanation!

I understand how tyre diameter and width impact traction and breaking.

In your experience, it is possible to build a single drive kart that breaks fine and has not traction problems when used "off road" (grass and gravel surfaces).?

 

[firemanjim]

Only if it's one fat mud tire in the back....Even that would have limits.... For off road, you really need a live axle. There is just no comparison......
EDIT I love to drive my daughters one wheel wonder on the streets. It leaves black marks everywhere I go. I use the typical 410/3.50-4 Knobby tires. I can ride in short grass with out loosing much traction. But gravel, mud,and wet pavement (my favorite place to play) will leave you spinning a tire.....

 

[Half-breeder]

IMO... go Live axle w/ good sized wheels(13"-15")... and a TC, geared at around 5.5:1-5:1... 'should' break traction fine, upon turning... and speaking of turning... start your homework on Camber/Caster/Ackermann... itll be handy when tryin to turn on pavement. Just remember to equate the 'rake' you'll have w/ the larger wheels in back.

Not sure your braking idea(s), but a mechanical disk setup would work very well for such a light kart, IMO.