Spider carts Grand Daddy build

LightningTeg

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Awesome build. I've purchased the plans and reviewed them, and I'm getting ready to buy parts to build one of these for my 8 year old. Hoping to have some of the basics sitting under the tree like wheels/tires, axle parts, steering, etc... to get us started.

I'm curious about a few things:

* Do you ever wish you had reverse (I'm considering adding a forward/reverse gear box as well as a torque converter)
* I'm considering going with 20x10-10 wheels/tires rather than the 18x9.5-8., Do you think I'd run into problems with steering (maybe easily modded by lengthing the nose and extending the arms further out)? I may also go with a 22"x7" tire up front on a 12" 4on4 trailer rim, and also planning to update the spindles to the 3/4" ones from BMI.
* Did you buy your spindles or build them yourself?
* I saw that you widened the chassis cab area, would you also consider lengthening it? (I doubt I'll be able to drive this thing at 5'11" 250, but I'd like my wife at 5'8"/125 to be able to ride in it comfortably).
* Is it possible (and are you willing) to share the plans you drew up?
Yes, I am not sure what route Im going to go. I may grab a box out of an ATV or something that can handle the power
You will have a harder time turning at low speeds the larger the wheel
The spindles are from BMI karts. Get the 3/4" version and buy the sealed bearings!
Not for me I'm 5'3" LOL
I can send you STP files

What size tires and rim did you go with? looking to start this myself next week, just bought the plans and the square steel
18x9.5-8 with knobby tires
 

Beep

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Yes, I am not sure what route Im going to go. I may grab a box out of an ATV or something that can handle the power
You will have a harder time turning at low speeds the larger the wheel
The spindles are from BMI karts. Get the 3/4" version and buy the sealed bearings!
Not for me I'm 5'3" LOL
I can send you STP files


18x9.5-8 with knobby tires
Ok great thanks! so are you saying you used 3/4 bore 4x4 for the front? i was trying to find those, ill keep looking. What did you use for the rear axle itself and also the rear hubs if you don't mind, and thanks for the info!!
 

Beep

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So i found the axle and spindles. They should be here this weekend. The only trouble i am having is finding the bushings. They should be 5/8 ID x 1in OD x 2in length, correct? where is everyone finding these? Ebay wants $20 a piece....
 

LightningTeg

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Beep

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The bushings for the A-Arms, for the front suspension, the 1" tube to connect the upper and lower control arms to the frame.
 

LightningTeg

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Meh you dont need bushings there. Just run a 5/8 bolt, drill and tap the tube for a grease zerk and call it a day.

I havent run any on mine and its still solid. I meant to do the grease zerks but I am lazy.
 

LightningTeg

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Also, Ive found many in the ~$4-5 range

 

Beep

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ok thanks, I dug through their site a little more and found the correct size.
 

Jrivera98

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Hey everyone! New to forum, but I find myself here researching things often so figured I would start a build thread.

Started this project 3 months ago. I've always wanted a go kart / off road buggy when I was a kid but my dad would never let me have one because he didn't want me tearing up the lawn lol. Now I'm almost 30 and have the space to do what I want!

Did some digging and found the spider carts granddaddy plans and determined that was a good route. The plans themselves are OK, but as an engineer I felt the drawings / work instructions were lacking. I ended up modeling the entire thing and making it a bit wider to accommodate the car seats I got from a parts car. Most of the frame is MIGed although I decided to TIG the A arms to get some practice and because TIG forces one to take the extra time to get it right.

So far I've got quite a bit of the frame done. I just started cutting pieces for what I call the "rear module" that carries the engine and rear axle.

Which brings me to my first question:

Based on my model, I'm going to need a 52" L axle. I'm not sure where to get one that long and whether I should get a Solid/Tubular axle and AL or Steel. The plans call out for a 1-1/4" axle for the 10hp engine the author used. I plan on using a Predator 420cc (15hp/18trq) and probably doing some performance upgrades. What do you guys suggest for axle?

Heres some pics!





















Quick question what angles did you cut when doing the side rails next to the seats. I know the last part that measures 34 inches but I'm stuck on that! Thanks
 

redflash

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on my arachnid ( single seat) i built the mazda miata differential as shown on you tube...it gives me the rear end for turning corners without having to drift the outside tire. it cost me about $100 to build, but it gives me a real differential out back...very compact and not very heavy.

Da Flash
 

LightningTeg

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Quick question what angles did you cut when doing the side rails next to the seats. I know the last part that measures 34 inches but I'm stuck on that! Thanks

Honestly cant remember. It was more of a guess and check thing. The right side came out like poo and the Left side looks good lol.

on my arachnid ( single seat) i built the mazda miata differential as shown on you tube...it gives me the rear end for turning corners without having to drift the outside tire. it cost me about $100 to build, but it gives me a real differential out back...very compact and not very heavy.

Da Flash

Hmm thats cool. Definitely interesting in building another rear module for IRS and possibly gearbox, but not right now.
 

ideafija

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friend, I will do the same !!! It's great and many congratulations because I saw the video and it looks great !!, is it possible that you can share the source file to know the measurements? (ideafija at gmail dot com)
 

Warrior

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Hola estimado soy Jorge de argentina y tambien sueño con armar un grandaddy go kart para mi hijo de 7 años. Quisiera saber si alguien de ustedes me podría hacer el favor de pasarme el plano del chasis con todas sus medidas. Gracias. Cuando comience a armario les mandaré fotos. Saludos
 

miniblazinbmx

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Steel....1-1/4" will do... Need to get a key shaft of that length..
I might advise against those cheap shocks. I got them for our kart and they couldn’t cut the added weight. We’re under 400 lbs everything included easily. They have a heavy duty version on bmikarts, or Amazon, but I didn’t get those at first. We’re going gas charged now with a longer stroke to correct alignment. Just a heads up bc under weight and load these wouldn’t work for a our Yerfdog resto. Which is significantly lighter than yours probably.

This build looks sick. Can’t wait to see it finished.!
 

Tonyzsi

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Wow, awesome cart!! I wish I had your skills and tools. Is your gas tank still mounted in it's stock location? It looks like it's raised to me and that's what I'm trying to do with mine. I've built 2" "C" brackets out of 3/4" x 1/8" steel flat bar to mount the tank up a little, but they keep cracking where I heated and bent them. Thinking of going with a 1 1/2" flat bar for more strength, but wanted to see if you did something else. Thanks.
 

MTScott

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Yes, I am not sure what route Im going to go. I may grab a box out of an ATV or something that can handle the power
You will have a harder time turning at low speeds the larger the wheel
The spindles are from BMI karts. Get the 3/4" version and buy the sealed bearings!
Not for me I'm 5'3" LOL
I can send you STP files


18x9.5-8 with knobby tires

I know this is a year later, but I'm finally getting after this build. I have the base tacked together, and all the parts cut for the upper frame rail.

I hear what you're saying about tires. I've decided on going with a 21x7, on a 10x6 wheel. I'd prefer 10x5, but can't seem to find it for a 4on4 bolt pattern. I expect/hope that the narrower "rounded" tire will steer just as well (if not better) as the 18x9.50 tire. This is also a common size set. So, it'll be 20x10-10 rear, and 21x7-10 front.

Another question, for anyone.... The plans call for the 12x5 mount plate (which BMI designates for the predator 212cc):
https://www.bmikarts.com/12-x-5-Motor-Mount-Plate_p_1119.html

However, I've purchased the predator 420cc, and bmi sells a different mount plate designated for that at 14x8:
https://www.bmikarts.com/14-x-8-Motor-Mount-Plate-for-13HP-Engines_p_10462.html

I assume the plate I need to start with is the 14x8? Or does it matter? Are the mount holes/slots the same?

I'm considering lengthening the axle/motor subframe by 2", as I've seen posts in which guys had trouble with the engine running into the cage from.
 

miniblazinbmx

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I know this is a year later, but I'm finally getting after this build. I have the base tacked together, and all the parts cut for the upper frame rail.

I hear what you're saying about tires. I've decided on going with a 21x7, on a 10x6 wheel. I'd prefer 10x5, but can't seem to find it for a 4on4 bolt pattern. I expect/hope that the narrower "rounded" tire will steer just as well (if not better) as the 18x9.50 tire. This is also a common size set. So, it'll be 20x10-10 rear, and 21x7-10 front.

Another question, for anyone.... The plans call for the 12x5 mount plate (which BMI designates for the predator 212cc):
https://www.bmikarts.com/12-x-5-Motor-Mount-Plate_p_1119.html

However, I've purchased the predator 420cc, and bmi sells a different mount plate designated for that at 14x8:
https://www.bmikarts.com/14-x-8-Motor-Mount-Plate-for-13HP-Engines_p_10462.html

I assume the plate I need to start with is the 14x8? Or does it matter? Are the mount holes/slots the same?

I'm considering lengthening the axle/motor subframe by 2, as I've seen posts in which guys had trouble with the engine running into the cage from.
the 420 has a diff mounting bolt pattern.
 
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