Grand Daddyish build

[TNThomas]

Hey folks new to Karts and new to welding. Im building the Grand Daddy from Spider Carts. I stretched the main cabin/frame a foot, and generally beefing everything up everywhere. The plans call for 1×1" and 1-1/4x1-1/4" 14 guage, but im using way more of the 1-1/4 for extra support. Im a big dude at 6-8 340lbs. Im primarily building this for traveling distance on groomer snowmobile trails in Idaho, and sand dunes in Idaho, Oregon, and Washington.

With that in mind im going BIG for the tires. 22x11-8 all around. I know these will be tough to steer, but ive had great success in sand with this before on different vehicles. Im also making my own beefy spindles/steering brackets with this in mind.

Im for sure doing at least a 420, or 440cc. But im slightly worried Ill be under powered when riding around with my 330lb Dad. By myself im sure the 440cc would be killer, even with my 3 year old. Should I just bite the bullet and get the 670? My wallet says no, but long term it's probably the right choice.

Two crazy ideas im still entertaining: putting an extra axle in the back for extra weight distribution on axles, extra float, and extra traction, it would be connected via sprocket to the primary axle. 6 wheels total. (Im thinking of building skis for the front in snow).

Last crazy idea is a 3rd "gunner" seat above and to the rear of the main cab, very similar to the Chenworth military buggy. Spacially this would work well with the 6 wheel idea. One thing I like about the 6 wheel 3 seater idea is that while it will cost more, it would make my buggy totally unique, allowing me to sell it for more if I ever decided.

Part of me wats to go big with 6 wheels, 670cc, 3 seats, but part of me says go standard 2 seats, 4 wheels, save money and get the 440cc. Thoughts?

Dune photo is my old beater 1999 Ford Escort. Movie theatre seats in the back.

 

[TheDADgineer]

Following! Sounds like a great build. I'm working on a similar but smaller build. Minus the 6 wheel and gunner seat More power might be nice. Especially in sand! Good luck to you, sir.

 

[fuzzy]

TNT, the build sounds awesome. I have been a lurker on this forum for a couple of years and this is my first post, and started a Granddaddy build about 1.5 years ago to work on with my daughters, now 10 and 13. I too stretched and widened the entire system and departed greatly on the roll cage, even adding a bull bar up front and made extensive use of the 1.25 tubing. Using a Predator 420 stock for now with a Chinese 40 CVT. Running 22x8x10 tires on front and 22x11x10 on rears. Starting with a 60 tooth axle sprocket, expect I need more teeth when I get it going (10 on drive). Planning on mounting motor and jackshaft this weekend.

For the steering box you make a good point. I am using one of the kits from ebay, but made my own tie rods from DOM. The rack is weak, have added hold down points to it. For the sand I would suggest looking at the Latest Rage 8" rack. If you haven't built the front suspension block yet I would suggest increasing its dimensions, but it will impact your king pin length. If you want to upgrade the a-arm attachments I would suggest looking at the Amazon for the a arm attachment that has the bushing already installed which will screw into a weld-in bung. I should have done this, but daughters poured the poly bushing from molds.

Sorry for the long windedness, but yours sounds similar. Old pic attached.

 

[TNThomas]

Thanks for the photo! I downloaded it for ideas. Yup, your stretch/widen looks very similar to mine. I really like what you did with the roll cage/steering box. It has a "cross cart" feel to it. Nice bumper too. Your whole front box looks much stronger than the build plans. Yup, I lengthened my steering box 2", widened it 2", and made A arms 1" longer. Did you make all your own mounting brackets/DOM tubing for a-arm pivots? Looks so, these are way over priced to buy online. I was thinking of just making these as well. Any pro tips would be appreciated. Yea, I bought the "Latest Rage" 11" steering rack, I am just debating how far forward to mount it.

 

[fuzzy]

Thanks, I wanted to give it more buggy feel than what the plans had. A arms were lengthened and spread some too due to the tire size. Stub axle is from a trailer kit, cut the shaft with a whole saw and welded to 1.25"OD x .625"ID DOM to make a spindle, a arm ends are 5/8" heims. Other end of arms are 1.5" pipe where we poured the polyurethane bushings. That is the end where I would have used weld bungs and pre-made attachments, but my girls learned a lot about polyurethane and hardness. Tabs welded to frame are 1/4" plate, just have a stick of 2" wide bar stock I use for everything, way overkill for a kart. Rear tab at each joint has a gusset back to frame to take rearward loads, 5/8" bolts used on a arms, 3/4" bolts used on rear swing, all castle nuts. I have a 2" diameter rod of polyurethane I cut for washers/spacers between suspension parts to soften, all coated with silicone grease.

No pro tips here, my method is lots of tacking and try again and looks at what everyone is trying here. Biggest thing about size I have found is finding coil overs that provide the load capacity I want, but stay within a decent budget. The front can travel 10" stop to stop, but I really can't find a coil over in the range I want to spend that can utilize that much.

 

[fuzzy]

What you did with back of your frame is a good idea, keeps the framing simple and gives you more flexibility going up. Third seat would be good, could be used as a good mobile hunting stand using some concealment blankets.

 

[TNThomas]

Huge thanks! VERY good info! Thats really smart using trailer hubs for the front! I hadn't considered that. I was going to do 3/4" dia spidles for the front, but still didn't feel confident with that. Those look to be 1", nice! Im definitely doing that. I feel that is the single weakest component of the entire build, and the the trailer hubs/spindle would solve that.

Stronger, and cheaper. I never realized you could "pour" bushings, ill have to read up on that, also good. I like going overkill as well, its just smart to make everything stronger. I got a 2" female reciever hitch I plan on welding to the front steering box so I can make a ball mount that slides in and just tow it where I want to go. Swap on trailer tires and tow it a few hundred miles.

Your roll cage modification lets the driver and passenger kick their outer leg up on the long downward angled 1-1/4 tube as well, very comfy! Build plans there is a piece that would be in the way.

What shocks are those on the front? Ive been doing alot of research on quality/price, and I think im going to try out some Monroe shocks listed below. If they are too stiff for the front ill just toss them on the back. American made, actual steel (not cast Chinese mystery metal), 14"ish long, and about $32 per, the only downside is they have about 4" of compression/rebound from the readings, but my thoughs are balloon tires will be taking up quite a bit anyways at low psi:

https://www.amazon.com/Monroe-58241...6693624#aw-udpv3-customer-reviews_feature_div

 

[TNThomas]

And it would be a great mobile hunting setup. Those are some pro tips too! Haha, I do actually plan on making some sort of rifle rest on whatever cross bar holds my steering wheel bracket. There is an old dredge mine that I long distance shoot at in Idaho, and it would be much nicer to sit than lay on rocks! Haha

 

[fuzzy]

I've added a bit more triangulation to the cage for strength in case of roll over, but still roomy. For sure too big for back of truck, plan to trailer this around. Front shocks are the 340 mm motorcycle shocks from Amazon with the reservoir, will see how they perform. Looked at a few different layouts, The bar is going across the top so I can cut its vertical connectors down until happy with the ground clearance. Can drop the front end from 3' and the front compresses about half way then rebounds to a stop. The rear shocks are the heavy go kart shocks from BMI, they won't be enough due to my geometry, too much leverage on the shock. Looked at the Monroe you referenced originally, my concern then was they would be too stiff, but not now.

 

[fuzzy]

We hunt in far south west Texas, perfect area for running this around. My thought was to make a removable deck from 1" tubing with the floor being expanded mesh. Deck would be as wide as top of cage and about 6' long, probably need a couple of kickers down to front of frame. Use tractor pins to mount to kart frame. Fix seat on swivel in middle. Have some fiber rods similar to those used in tents and drape concealment blanket, coupled with the elevation in the area it would be a nice platform.

 

[madprofessor]

You mentioned something about Monroe? Talking shocks? Here's the ones (not white, mine are black) I put on current kart, will attach pic.
Amazon.com: Monroe Shocks & Struts Max-Air MA775 Shock Absorber : Automotive
Trust me, they're not stiff until you get past about 75 psi. Then you can make them into just a pair of strong support poles.

Hate raining on a part of your unique kart idea, but I've had a dozen pages of scale drawings of a Ma Deuce (M2) for months now. Will be making a nearly exact all-steel replica to mount Rat Patrol style on current kart. You know the fixed version of those things are almost 5' long overall?
Have a genuine 50. cal. ammo can from WW2 that actually has the specific "M2" stamped in it along with ".50 CAL", the "U.S." stamp, and the braille version of "explosives" (a round ball with lit fuse). Getting that's what inspired me to do the Ma Deuce. Oh, it's hinged on the long side.

 

[madprofessor]

Seen more vehicles in exactly that old Escort's predicament than I've got fingers and toes, on our dunes and on our beaches. Been in that same predicament several times myself, even buried a Kawasaki 350 Bighorn in a dune. You anywhere near the home of sand central, Jacksonville, Florida?

 

[TNThomas]

I've added a bit more triangulation to the cage for strength in case of roll over, but still roomy. For sure too big for back of truck, plan to trailer this around. Front shocks are the 340 mm motorcycle shocks from Amazon with the reservoir, will see how they perform. Looked at a few different layouts, The bar is going across the top so I can cut its vertical connectors down until happy with the ground clearance. Can drop the front end from 3' and the front compresses about half way then rebounds to a stop. The rear shocks are the heavy go kart shocks from BMI, they won't be enough due to my geometry, too much leverage on the shock. Looked at the Monroe you referenced originally, my concern then was they would be too stiff, but not now.

Ah, very smart with the vertical attachments. That opens up your options quite a bit for the front. And good thing beefing the roll cage up too. Might as well if the top deck is used for hunting, win-win. After thinking more, if I do end up doing a third seat, ill just bolt it to the roof, similar to what you are saying, but probably lower. Those rotating captains chairs are pretty slick though! Im going to do the 670 and 6 wheel setup, thats still on though!

 

[TNThomas]

Seen more vehicles in exactly that old Escort's predicament than I've got fingers and toes, on our dunes and on our beaches. Been in that same predicament several times myself, even buried a Kawasaki 350 Bighorn in a dune. You anywhere near the home of sand central, Jacksonville, Florida?

Thanks for the info on those Monroe shocks, ill take a look. Are they "Too stiff" at/above that psi mark? I couldn't be further from Florida, haha, WA state. That photo is from an old dried up lake bed from the last ice age. Place called Christmas Valley Sand Dunes in south-central Oregon. Central, Southern, and Eastern Oregon are fantastic for offroading, absolutely nobody out there. Still the wild west as far as I'm concerned:

 

[madprofessor]

Ahh, Oregon! Took the long drive up there from Sacto a couple of times for shroom hunting. You're right, nobody but shroom people out there.

Are they "Too stiff" at/above that psi mark?

Never really experimented with the psi after seeing how stiff they could be made to get, beyond what I was after in stiffness. I can tell you if the psi is lowered from there, you have infinite adjustability on how soft, how much rebound, how much compression speed, all of that you want to reach. With the shrader valve mounted right there on top of shock tower, feeding both shocks, I can make changes in seconds.

Front shocks are the 340 mm motorcycle shocks from Amazon with the reservoir,

Before you ever put a load on those shocks, rub in some Nevr-Seez lube into the adjustment threads top to bottom and all the way around. You'll be amazed how wide the range of adjustment is on those, massive amount. I have the 420mm version in a very unique diminishing resistance cantilever setup I designed, pics below. Mine compress to 15.5", extend to 25.75", and yours should have a ton of travel also.
EDIT: Oops! That closed/open measurement is what my air shocks can do up front. The 420mm coilovers in the pics below have a nice long travel in them though, see 3rd pic when frame was being designed to see swingarm traveled up and sitting on 2 milk crates and a toolbox.

 

[TNThomas]

TNT, the build sounds awesome. I have been a lurker on this forum for a couple of years and this is my first post, and started a Granddaddy build about 1.5 years ago to work on with my daughters, now 10 and 13. I too stretched and widened the entire system and departed greatly on the roll cage, even adding a bull bar up front and made extensive use of the 1.25 tubing. Using a Predator 420 stock for now with a Chinese 40 CVT. Running 22x8x10 tires on front and 22x11x10 on rears. Starting with a 60 tooth axle sprocket, expect I need more teeth when I get it going (10 on drive). Planning on mounting motor and jackshaft this weekend.

For the steering box you make a good point. I am using one of the kits from ebay, but made my own tie rods from DOM. The rack is weak, have added hold down points to it. For the sand I would suggest looking at the Latest Rage 8" rack. If you haven't built the front suspension block yet I would suggest increasing its dimensions, but it will impact your king pin length. If you want to upgrade the a-arm attachments I would suggest looking at the Amazon for the a arm attachment that has the bushing already installed which will screw into a weld-in bung. I should have done this, but daughters poured the poly bushing from molds.

Sorry for the long windedness, but yours sounds similar. Old pic attached.View attachment 128315

Hey Fuzzy, I have decided to partially mimic your front suspension/roll bar mods. Thanks for the photo upload, ive probably spent over an 2 hours looking at it. Thanks for the photo!

 

[TNThomas]

Working in the roll bar.

 

[fuzzy]

Your welds look really good.
I like the idea of going the 670. Starting off you wouldn't have to mod it any and still have plenty of go. I haven't looked at the CVTs available for that hp range. Xpeedingrods is where I bought my knock-off comet 40. They have replacement CVTs for the production UTVs.

Didn't work any on the project this weekend, went to see Chris Stapleton.

 

[TNThomas]

Thanks! I went a little wider with the front of the roll cage than yours, and tried to make my roof "rack" as big as possible. Yea, that was my thoughts with the 670. From my research a series 40 will work with the 670cc, but you will burn belts up REALLY fast. A better option is the knock off Comet 780 cvt. Rated for 20+hp, and the gear ratios are apparently right on the money for engagement @RPM range, you can get replacement springs to adjust this range, and the belt is bigger/wider than the series 40.

The Comet 94c apparently would work too, but its truely designed for the high rpm range that snowmobile engines kick out. A bit higher than what the 670 does.

Sounds fun! That guy is awesome.

 

[TNThomas]

Had to put the build on hold for a few months as we are buying a new house, and selling our old one. But, I was lucky enough to get a new in box Predator 670 for $600 yesterday off the second hand market! The gentleman I bought from was a similar minded gearhead. He gave me a good idea on using a flywheel and starter for a reverse setup! "Push - button" reverse.