art car suspension

[mnjlovell]

is it necessary? We are modifying an existing art car that we picked up this year. its a golf cart based chassis and the existing suspension cant really handle the weight we would like to be able to put on it (6-8 people).

I know there are a lot of golf cart based art cars out there. what can be done (inexpensively) to increase the load capacity.

Hazmatt

[Jackass]

What's the make of the cart? Some offer heavier duty springs, otherwise you can block it out but that may end up cracking the frame or suspension if overloaded too much.

[mnjlovell]

its a mid 90's EZ-GO.

I dont plan on running an insane amount of weight on it. I am thinking of blocking it out; and reinforcing the frame/axle/suspension arms if needed.

[gyre]

Ask the factory and the cart forums.

Every vehicle has different weak points.

How much weight has been added already?
Ultimately you are limited by the drivetrain.

Springs, shocks are easy.
Remember wheel bearings too.
Tires, wheels.
Find out how far you can take it and if that will be enough.

[Jackass]

its a mid 90's EZ-GO.

I dont plan on running an insane amount of weight on it. I am thinking of blocking it out; and reinforcing the frame/axle/suspension arms if needed.

They do make heavier leafsprings for the front and back on those.

[trilobyte]

I'm giving this a nudge over to the Preparation -> Transportation board, since that's a better fit for general purpose questions about design and construction. The year-specific MV board is better suited to posting info/progress reports on fully formed planned and announced vehicles.

As for the question at hand, I don't know that there are any requirements per se (though go to the Mutant Vehicles section of the main site, read everything twice, then contact the DMV to be sure).

[gyre]

MVs are required to be safe at the speeds they will be used.

[motskyroonmatick]

If it has leaf springs and they are the stackable type then you could consider adding single or multiple leafs to what you have. Many times the axles I have seen have a U bolt set up that could accommodate an extra spring or 2 stock. Adding just one leaf on each corner might have a dramatically positive effect on carrying capacity. You might be able to make you own leaf springs out of something you find off of a junked small car. I think blocking the axle is a bad idea. If you have to go that route make a soft block out of rubber with a top of hard flexible foam to lesson the shock loads transferred to the axle. My guess is mounting the block as far outboard as possible on the axle would be the best.

A properly tuned golf cart is easy to maintain 5 mph or less with. I've done extended periods at a walking pace with Golficus Carticus and it does just fine. I had to adjust all the throttle linkages and governor linkage back to stock to get to that point. If necessary a shorter belt can be put on and that will prevent the driven clutch from reaching it's maximum diameter thus reducing over all speed. This is assuming it is a gas powered cart.

Good luck and let us know how it goes.

[ranger magnum]

Your gonna want suspension. You can air down the tires, but you run the risk of popping the bead.

Best solution is to run airbags. You could splurge and get an onboard compressor. Smittybilt offers a 5 gallon airtank with compressor for about $500. The upside is you can also plumb in pnuematic accessories.

[Captain Goddammit]

Another good option for an overloaded mutant vehicle chassis is to add another axle.
As a mutant vehicle driver myself, I can tell you that even thorough you have a predetermined passenger limit, at times it will be exceeded, and your tires become the ultimate limit.
I've had too many passengers aboard and blown tires... and they were 14" passenger car tires. Golf cart tires are pretty wimpy. Bring spares!

[gyre]

Your gonna want suspension. You can air down the tires, but you run the risk of popping the bead.

If you are talking about lowering air pressure, this reduces weight capacity.

There are heavy duty tires down to 13".

[gyre]

High performance tires have higher weight capacity, but low profiles compromise this.
Don't go below 60.

On a budget, used V rated or higher tires may be a good bet.
Check the specs.

Good trailer tires will be 70 or 80 ratio usually.
Name brands may only be available by mail order.

[Elliot]

Additional thoughts:

By my observations, regarding tires in the automobile spectrum, perhaps Light Truck tires would be better than high-speed-rated tires.

High-performance passenger- and sport-car tires are rated for maximum safe speed, identified by a letter preceding the routine "R" for "radial". The further out in the alphabet, the faster the tire may be safely driven. "VR" is quite fast. "ZR" is even faster, somewhere north of 150 MPH.

Tire identification works as follows:
Let's use the tires on your little commuter car as example; P185/60R15.
P = passenger car tire.
185 = width of the tire in millimeters.
60 = height of the side-wall in percentage of the width, known as "profile".
R = radial construction tire -- all cars and light trucks these days.
15 = diameter of the rim.

I went out in the garage and looked at my brother's sports car. It has the very latest super-duper extra-expensive "two-hundred-mile-n-hour" ZR-rated tires; 275/40ZR17. But the weight rating does not impress me -- only 1,650 pounds. Yes, ridiculously low profile, as Gyre pointed out.

My pickup-truck is a different story. These tires have no speed rating at all. (Technically they are rated somewhere in the middle of the alphabet, but nobody cares since sensible people do not drive a pickup-truck particularly fast.) Instead, these tires are built for heavy loads, and are identified by the letters "LT" for Light Truck, at the beginning of the identification number; LT225/75R16. These tires are rated for 2680 pounds.

Finally, trailer tires. Many of these are of pre-radial construction, since the old-school design is stiffer and thus keeps the trailer more stable behind you. Pre-radial tires are known as Diagonal, or Bias Ply.

So here I have some ST205/75D15. I don't know what the S stands for, but the T stands for Trailer. And D for Diagonal. Strangely enough, these are weight rated for only 1820 pounds. But trailer tires come in many flavors. I have others who are so old-school (though brand new) that they do not even have modern identification numbers. They even take weird rims. But they are rated for 2790 pounds. Although that's not much more than my Light Truck tires.

Of course, I am comparing apples and oranges here -- various sizes that I just happen to have handy. But you can find specifications for every tire on Earth on the interweb.

Bottom line, so far as it goes, for tires in sizes for automobiles and up, I'm thinking Light Truck -- and heavy truck, of course. And for dawg's sake, use fairly new ones.

Oh.... Golf cart tires? All right, let's go back outside, this time to the barn. And... the tiny tires on Lady Sophia do not even have a weight rating. They are not even allowed for highway use. And they have a maximum inflation pressure of 22 PSI, which is deep in pipsqueak territory.

The tires on Millicent The Bus are 295/75R22.5 and can carry 6175 pounds. Yes, these are 18-wheeler tires.

Carry on!

[gyre]

Good point about truck tires.
I didn't mention them because they are, on average, very poorly made and in high demand used.
Hard to find even usable tires of that type used.
Overpriced new, but a good choice if they fit and you can afford them.

V rated name brand tires are built very well and typically resist ozone rot better than most.
The very thick sidewalls and higher quality rubber will make an older tire take more weight than an older standard tire.
And they are common these days.
They do make models for heavier european cars that will handle considerable weight.
The issue is fitment though.

A note about tire ratios.
They are ratios, meaning that a 275/40 has a different sidewall than a 195/40.
Looking up tires for someone can involve a lot of math, as you can go up and down, changing ratios to adapt them.
Lower profile reduces load capacity.
You can go oversize by quite a bit, especially on a slow speed car.
There are also speed rated truck tires too.
Sadly rare also.
Those would make the best choice, followed by high profile performance tires.
If you're buying used, don't underestimate the age factor on standard grade tires.

Usually performance tires are made of softer rubber to begin with, so they are more functional as they age.
Tires have a lifespan rating which is more indicative of softness than wear factors.
Sometimes you can get fresh speed rated tires which are worn.
The tread is not a factor in many cases, though heat cycling may compromise performance.
Tires actually grip better with lower tread, except in rain.
Tread may not be a factor at all in a mutant only application.

If mixing brands, look carefully at actual dimensions, as they may vary from one to another for the same size.
Tire rack lists full specs as do tire companies.
This is critical on driven axles.

Trailers. I was able to find a 13" for my trailer that would carry a stunning amount of weight.
I'm told that trailer tires are made for towing stability, so may not be the ideal choice for a driven vehicle.
That may just be code for bias construction, but they tell me that they handle far better on a trailer than car or truck tires.

[dragonpilot]

Whatever you decide to do please give me a ride. Too often have I stood in the Deep Playa at midnight with my thumb out only to have the MV drive right by and stop just a short distance away to pick up a blond topless lady wearing silver platform boots and a gold-lame (accent mark over the "e") thong...

What's a guy gotta do?

[Captain Goddammit]

Hey did you guys read the OP's question? It's a golf cart, not a Corvette or F-250! None of the tire discussion here applies at all to his application. He's not gonna put Pirelli P-Zeros on it!
If I had a golf cart based mutant vehicle that was gonna be heavily (over) loaded, I'd look at adding an extra tag axle, and/or making sure I had a few spare tires. Use new or fresh tires and inflate them maybe a little higher than they say to. You'll be fine.

[Elliot]

Hey did you guys read the OP's question? It's a golf cart,...

Why yes, now that you mention it....

Oh.... Golf cart tires? All right, let's go back outside, this time to the barn. And... the tiny tires on Lady Sophia do not even have a weight rating. They are not even allowed for highway use. And they have a maximum inflation pressure of 22 PSI, which is deep in pipsqueak territory.

But what's a little... uh... tread drift among friends.

[theCryptofishist]

*crawls out of thread*

[Captain Goddammit]

But what's a little... uh... tread drift among friends.

Hahaha ok good point

[Bounce530]

Best solution is to run airbags. You could splurge and get an onboard compressor. Smittybilt offers a 5 gallon airtank with compressor for about $500. The upside is you can also plumb in pnuematic accessories.

Airbagit.com has bags/comps/tanks for alot cheaper.

[junglesmacks]

Best solution is to run airbags. You could splurge and get an onboard compressor. Smittybilt offers a 5 gallon airtank with compressor for about $500. The upside is you can also plumb in pnuematic accessories.

Airbagit.com has bags/comps/tanks for alot cheaper.

Speaking of which, Bounce..

You have the best personalized license plate associated with said air bags.. ever. Ever.

[Bounce530]

Thanks!

[Elliot]

I think I know her.

[Znobyzom]

For the OP.
I will be blunt. You picked the wrong platform for the type of MV you are building. I Don’t even need details on the build. Lets do some math. Golf cart designed to carry two people with clubs. 2 people x300lbs each+250lbs for clubs = 850 lbs. lets say 1200 lbs just cuz it’s the best Golf cart ever.
Now with the parameters you set. 6-8 people including the driver ? lets go on the low side. 5 people + driver. Lets say you only let on people averaging 150lbs.~ 900 lbs + added structure weight go light say 1200 lbs or more. So on the light side 2100 lbs.
….. people with a 250 lbs average. You are up to 2700 lbs close to 3000 lbs. on a golf cart made for two people.
Sorry but I would find a new platform for this build. If you are just finding out now after you built it….. it can’t carry the weight… now what do we do?. Next time Plan first….. don’t build blind. For weight carrying in this build I would use the cart for pulling a trailer moving people and the weight to the trailer. Gear down the Golf cart for more low end torque . And hope the drive train doesn’t break out in deep playa…...bring tow truck money with you. Good luck~

Mozy Fucking Bonz~

[Elliot]

Blunt is good. We all need such reality checks from time to time. I scrapped an MV I was well along with when I realized I had bitten over more than I could chew. Always a great learning experience.

We had a discussion on this board a while ago about the theoretical ideal MV chassis. Of course, many MVs are built from scratch, but so far as ready-made chassis go.... There seemed to be reasonable consensus that a 4x4 pickup chassis should do well. It would have automatic transmission. And it would have manually locking front hubs so you could drive around in Low Range -- Playa speed -- without dragging the brakes, yet not scrub the front tires much. Just a thought.


Edit: Average golfers at 300 pounds.

[Znobyzom]

Yeah.....big golfers.... I was trying to be nice with 1200 pounds of load capacity. A two-person golf cart may have more of a weight limit of about 600 pounds with a load capacity of 800 pounds. hope this helps. watch out for playa snakes~~~~~~~>

[oscillator]

Ever consider gender reassignment? Now *that* would be radical self-reliance.

...to pick up a blond topless lady wearing silver platform boots and a gold-lame (accent mark over the "e") thong...

What's a guy gotta do?

[theCryptofishist]

Ever consider gender reassignment? Now *that* would be radical self-reliance.

...to pick up a blond topless lady wearing silver platform boots and a gold-lame (accent mark over the "e") thong...

What's a guy gotta do?

Only if you use that "Suture Self" and have do it yourself surgery.

[moltensteelman]

If the golf cart has 8"x 7" rims you can mount snowmobile trailer tires on them. The tires are 18.5 x 8.5 x 8 and are available in load range B (770lbs) or load range C (940lbs). These are high speed highway tires with stiff side walls and available new from most tire stores for about $50 each. Air pressure rating is 35 psi. At 5 mph they can handle some overloading without risk of a blowout. Coil over shocks can be easily added to the susspension to hold extra weight and should be fairly cheap at motorcycle wreaking yards or you can get the cheap dune buggy front coil over shocks. If you go with blocks there are many susspension stops made from polyerethane that are designed for a certain amount of compression, check off road and dune buggy shops. If the golf cart is electric it helps to upgrade the speed controller to a 400-450 amp controller to give the motor extra torque, or a 600 amp speed controller if your upgrading the motor and wireing. I've seen aftermarket golf cart motors from 4 to 16 hp. If the golf cart is gas powered with a centrifugal force belt drive it may slip the belt with the extra weight esspecially when it gets playa on the belt. 6 to 8 people is really pushing the capabilities of a golf cart.

[Elliot]

...snowmobile trailer tires on them. The tires are 18.5 x 8.5 x 8...

Yeehah! My golf cart tires are 18 x 8.50 x 8. Don't know if the OP's tires might be different, but this sounds entirely realistic indeed. My local tire shop will think I've gone off the deep end when I ask him for anything related to snow!