Question about what size tires and wheels I can run on original thunder kart

[ingrams21]

Hey guys new to the group but long story short we have rebuilt my old thunder kart pics are attached. My son is wanting to add larger tires to this kart for off road use and I am wondering what size tires should I get the original tires on this kart are :
Front 4.10/3.50-4
Rear 13x5x6

the wheels or rims on it connect through the tire and bolt. So it’s not like a single rim. Would the Amazon tires attached work for the rear? If they do what size should I go with for the fronts keep in mind the fronts are 4’s not 6’s

 

[ingrams21]

These are the shaft measurements

 

[Denny]

Unfortunately with using a centrifugal clutch you can not. Without significant rework to the rear of the kart you are limited to the smaller sized tires.

 

[Hellion]

You're describing split rims. You'll need inner tubes for those.

For bearings, they are usually just a press-fit into the hubs. You may not need the type you showed us, as that black ring is designed to prevent it from going too deep into the hub but they will still work. Usually a go kart hub has an inner ledge where the bearing is seated flush against. If your hubs lack this "ledge" then the rings are necessary.
Be aware that most bearings like these can be repacked. If the ones you have now are noisy, you can pry the rubber seal out carefully (don't damage it) and slather some bearing grease in there and reassemble. It should work well unless the bearings are rusty, pitted and too far gone. Most people think they are disposable, but they can be maintained.

Denny is right. With monster tires, you will just burn out the clutch because they will be too big for the gear ratio. You will finally need a TAV / Torq-A-Verter. But a clutch and some road tires are fine for pavement.

The ideal gear ratio for a 13″ tire is 6:1, (Gear ratio = teeth in axle sprocket / teeth in the clutch sprocket), if you want larger tires then you’ll need to decrease the ratio accordingly but it will affect your speed. You should read this thread:

https://www.diygokarts.com/community/threads/drive-ratios-for-dummies-gearing.26445/

 

[Hellion]

Assuming the Scamazon tires fit the rear rims, it would be ideal for the front tires to match the rear tires; a matching set like most passenger cars.
You'll need new 6" rims for the front.

That's what I would do for parts commonality and aesthetic appeal.

 

[JimD]

All the advice is very good you are getting. A picture of what the rear axle that the drive tire is on right now will explain better why you have to stick with tires very close to what you have right now. If memory serves me correct, it is not a live axle but a bolt welded to the frame that the drive tire is rotating around on, called a stub axle. Unless you are going to do some major redesign to the kart which is certainly possible. You will get great advice on how to redesign the kart to add the axle and you will learn how to weld.

 

[Hellion]

Right Jim. A "one-wheel peel" limits the options -- not to say the OP couldn't custom weld new stubs on either side of the kart. One-wheel go karts are not ideal for off road because as soon as the drive wheel finds itself in a rut or a depression all it will do is spin that wheel uselessly.

If that was my kart I'd be happy with what it is and run it as-is. The OP can always look for another more viable go kart or one of those newfangled ATV buggies with full suspension.

 

[ingrams21]

ok I am revisiting this post. so if all i wanted to do was add a 2" taller tire keeping the same width and stock wheels I have what size front and rear should I go with I am clueless to these : Front ( 4.10/ 3.50-4) & Rear (13x5x6) I added a larger engine and I am positive it will push 2in taller tires with ease. I do want to add a more aggressive tire though something with Treads at least. Its not so much mud riding but more in the yard and right now it spins out with the cheap All Terrain tires I got him. thanks again.

 

[JimD]

You got a "positive attitude" going so that is a plus. The other thing going for you is you are ONLY turning one wheel so getting a bigger "knobby tire" will help you get the bite but still be ready to keep swapping the rear tires since only the left side is going to get the abuse. I think the gearing you have right now is a 10 on the clutch and a 60 on the axle. The diameter of the 60 tooth rear sprocket is 7.38" try it and if the clutch is getting HOT get yourself an 84 tooth axle sprocket which is 10.25" in diameter which will help get you going easier if you are in a hilly region. You can use your old sprocket as the template for drilling the holes to match up to your wheel.

 

[Hellion]

ok I am revisiting this post. so if all i wanted to do was add a 2" taller tire keeping the same width and stock wheels I have what size front and rear should I go with I am clueless to these : Front ( 4.10/ 3.50-4) & Rear (13x5x6) I added a larger engine and I am positive it will push 2in taller tires with ease. I do want to add a more aggressive tire though something with Treads at least. Its not so much mud riding but more in the yard and right now it spins out with the cheap All Terrain tires I got him. thanks again.

What 13x5x6 tires are on it now? The tires in your photo? I am curious to know if those tires are actually 13" tall even in their worn state (they are close but rarely the advertised size).

Anyway I would suggest a 15x6-6 or 15x5-6 tire as the tire 2 inches up in size, but your options are usually limited to turf saver tires or snowblower tires. Something like this perhaps: https://www.amazon.com/MaxAuto-15x5-00-6-15x5x6-Blower-Thrower/dp/B07WFJ739W/ref=sr_1_16?dib=eyJ2IjoiMSJ9.G-G8IlqtvrQVaLXpNzk6q_ecDv4oLzTmJv9XZi03FleVZ0tjJm8RM-Xrr9TL967H_DDfEzX1SRNXpookLPqlWx4pPsLZQKwEuSaT_Ycl0OAdLibNh6zZd-8LA9buaYUxbXBoskY5TJF4YfC0lsl7vdKXlJKsxgkQ4vRBE_Rh0j7rDG7CV_UzPlwObEY4GeVOGFq2sTxs1VICCG9INsy1AdTebSmBFOVBXbpNzeX6FGY.YrlwUWpYuma2HjBjzupY062No-l5XZe08WvIXMZOkRw&dib_tag=se&keywords=15+x+6+x+6+tire&qid=1739817151&sr=8-16&th=1

https://www.amazon.com/Carlisle-Sno...ire&qid=1739817312&sr=8-21&xpid=q4hjmU2rkYDz0

Personally I'd get the cheapest set of 15" Turf Saver tires I could find and use them

 

[kukrasdeluxe]

All the advice is very good you are getting. A picture of what the rear axle that the drive tire is on right now will explain better why you have to stick with tires very close to what you have right now. If memory serves me correct, it is not a live axle but a bolt welded to the frame that the drive tire is rotating around on, called a stub axle. Unless you are going to do some major redesign to the kart which is certainly possible. You will get great advice on how to redesign the kart to add the axle and you will learn how to weld.

Good advice here. A picture of the rear axle would help. If it’s a stub axle, you’ll need a major redesign to change tire size. Adding a full axle is possible but requires welding skills.

 

[JimD]

I would shop around to you find some nice knobby tires you like that are the SAME size as the ones you are replacing because the kart is a stub axle and you need the rims you have to line up for attaching your rear sprocket. You are only driving one wheel so your traction is really going to be limited. The biggest problem you have if you change anything is getting the sprocket attached to the wheel. If you want to do it correctly to have a live axle then you need to be able to weld on a plate to the frame, get some pillow block or flange bearings, buy an axle that has a keyway and threaded on the ends, (axle size go with a 1" so if you do hit any stationary object turning to sharp and hitting it with the rear tire you will not bend it, buy new tires that have a keyway that matches up with your axle but wait until you get the tires to figure out the length of axle you need, then you need a carrier for the sprocket and look closely at the brake to see if the one you have right now will slide on the new axle side because more than likely you have to replace that also. So it really turns out to be a major job and the question you have to ask yourself, do I want to take this all on or go find a different kart now that i know what I should be looking for.

 

[Hellion]

If it’s a stub axle...

It is.

It has not been expressly stated in the thread, but the dead giveaway is in photo #2. You can see the square tube "axle" running the width of the frame and it is welded in place. The right side transitions to a 5/8" stub axle which is welded onto the end of the 1" (my guess) square "axle". The same is true for the left side but it is obscured.

Adding a full axle is possible

Full live axle, aka 2-wheel drive. He could add bearing hangers that split the frame where the present axle assembly is, which would not raise up the rear of the kart like under-slung bearing hangers would, like this Rupp kart...