Simplicity Broadmoor 728 XC

I’m pretty sure Johnathon ram ags the first year and the actually did really good for what they were. What about these?

https://www.amazon.com/Kenda-K472-Bias-Tire-22x11-00-10/dp/B00D6OIGYO

I run a similar tire on the AMF and was really impressed, slightly shorter lugs but very flexible and gripped logs and such well, unlike the bar tires I used in the past, shorter bars might be good for getting the rear to slide around turns also

Ps they have those for about 125 a pair on eBay

Thanks for the link @creepycrawler. I may go with something like that.

Here’s a couple mock up pictures. Just getting a really rough idea of how it’s all gonna end up.

Cool, I really like the seat, should help keep ya in place

Really getting the engine and trans close.

Is that an onan or briggs opposed?

Thanks, yeah that seat is super light weight. It’s a tad flimsy but I think it’ll work. Only $15 so you can’t beat that. The engine has to be about that far back to allow clearance for the front wheels steering and suspension. I had the same problem with the rs design. In the case of the rs I had planned on putting the engine dead center and fitting it up between the front wheels. But the rs was gonna be 42” outside width and now I’m down to 36”. Also I’m lining the belts up for direct drive without a jackshaft, so the engine has to be way over to the left side. But I think it’s still going to be an inch or two farther forward than the engine on the adventure edition. I’m sticking with close to the same wheelbase as before.

The engine is a Briggs opposed but the orange one you see is my bare test fit block. It’s got no internals and all the tins that would stick out are on. It’s even got a fake starter made from exhaust pipe. Much lighter to pick up and move around.

My 1” keyed billets came for the rear hubs. They’ll get welded to the white hubs as an extension.

Got a steering column/gears from my sears suburban parts frame. The sears steering in the adventure edition has held up great the whole time I've had it. Not overly heavy weight wise and rugged enough to take a pretty good beating. Also the gearing is about right for fairly quick steering. I can't speak for other brands but I think it's like 3/4 turn in each direction to full lock. I need to make a hub to adapt an aftermarket steering wheel on though, both for this build and the adventure edition. I'm out of original sears wheels to use...

With the opposed there, are you going to need to move the steering column back or will the opposed be mounted where the head is in the same place as the side of the block of the 8 horse was? Hope I phrased that right. This seems like it is going to be a wheelie machine there!

You could weld a craftsman steering shaft to it. Really easy to find those wheels, many options that fit the same hub so when ya find one ya like you can stick with it. Slick splined aluminum hub too that will act as an engineered seal point. It’ll go before the box will, so it’ll help that box last in the event it sees a large shock

I plan on just putting the engine as far forward as I can without it being in the way of the front wheels. Then the steering column will be as far forward as possible. An issue I have with the adventure edition on rough ground is that when you wanna stand up on the running boards, the steering wheel is a little bit in the way and too close to you. I'd like to move it forward at least a couple inches. I don't want to lengthen the wheel base because if I do, it's gonna hurt the turn radius. So I wanna keep it about the same as the adventure edition which is pretty much stock sears suburban. I think it will all turn out fairly close though. I may keep the steering column a little more upright than it was, as long as it's not uncomfortable to hold the steering wheel like that. The engine is actually gonna be a couple inches (at least) lower to the ground than the adventure edition, so I don't think it should be a total wheelie machine but we'll see. I think it's good to have a semi light front for getting over stuff but it's a trade off for hill climbing. Everything is a trade off really. So you gotta try to get it where it's gonna work decent for everything. I'm measuring all the dimensions from the adventure edition and then tweaking them a bit. For example, measuring how far forward the crank shaft center is from the rear axle and how far off the ground it is. Where your feet are gonna end up and how high the seat is from the running boards.

Do you have pictures of the body you are going to use?

I actually planned on making fiberglass copies of the hood, grill, and rear fender to save weight. But I don't know if I will have that much time or not before the Top Tractor Challenge in august. I may use the actual metal parts either off the tractor in this picture or I have another one with the same hood and fender. I also have the fender from the adventure edition which wasn't used in that build. Either way, this is the style hood ect that will be on the tractor. I may even use a metal original grill but fiberglass hood and fender. It depends on how it all works out.

I'd say you should use as much origional steel as possible, just to keep it more origional. But fiberglass would save you weight, so that is more of a technical aspect. I just hope it turns out good for you. I love the old simplicity and allis tractors.

Are you planning on putting lights on it? Wouldn’t need them for the competition, but would be great to have at haspin if you wanted to do more with it than just compete. Maybe something that’s easy just to unplug and unbolt for the competition?

I did try to use as much actual simplicity parts as possible on the adventure edition and I thought about doing something similar with this build, using part of the simplicity frame. But I can have a much lighter and lower frame by making it custom, so I’m pretty much just going for performance on this one. Like modern stock cars or rally cars ect, they look like the model car they are supposed to be, but there aren’t many similarities with their construction. I do plan on having lights though yeah. A couple of LED headlights and a tail light. I plan on running a tiny kubota alternator with a belt because the ARC flywheel doesn’t have any charging system magnets.

Fixed the rear hub issue by welding these collars to the bmi karts hubs. They have two allen bolts over the keyway but I’ll also add a threaded hole on the side to help keep the wheel on. I’ll drill a divet in the 633 axles where the bolt goes. The welds turned out decent enough for me. I slid them over a 1” keyed shaft with a key installed to keep them lined up during welding.

I'd be proud of that weld, if I were you! That's some nice work!

Thanks, I didn't bother to V it in before welding, but I think it'll be strong enough for what it is. Had the welder set up pretty hot so it should be pretty good. I'm probably gonna start working on the frame pretty soon.

Added 5/16” threaded holes to the rear hubs. Threaded the holes themselves but welded the nut on in addition so it hada couple extra threads to hold onto. I didn’t like the idea of those small lock bolts only being on the key.


Started on the frame. The front part currently stops about at the front of the engine. After the wishbone is done on the front axle, I’ll run the frame up to hold the shocks. The battery will probably end up in front of the engine too.

The original 633 that came out of the adventure edition on the bench. This one has the flipped gear lock but is being taken apart to be properly welded. The blue 633 in the xc frame will also get locked. Don’t know which I’ll use yet but the black one has already seen some off road use (3 haspins)

The little adapter plate that connects the sears transmission into the suburban frame happens to have the perfect bend to fit the top of the trans. So it made sense to use that vs making a new one. I cut part of it away to save unnecessary weight. Ran 1” box steel up and over the trans to meet the bracket. I also set a stock high/low shifter in place just so I don’t forget that it has to go somewhere. Just like on the rs build, I plan on running a structure up and over the engine. The entire frame will be a sort of cage. The hood will probably sit right on top of that. Need to get some pulleys and then I can weld on the engine mount plate. Trying to be careful not to put in anything that doesn’t absolutely have to go there. It needs to be rugged but you don’t wanna go overboard when you don’t have to. Steering is gonna be a bit tight but we’ll see where that’s gotta go with the engine soon enough.

mr.modified wrote:

I actually planned on making fiberglass copies of the hood, grill, and rear fender to save weight. But I don't know if I will have that much time or not before the Top Tractor Challenge in august. I may use the actual metal parts either off the tractor in this picture or I have another one with the same hood and fender. I also have the fender from the adventure edition which wasn't used in that build. Either way, this is the style hood ect that will be on the tractor. I may even use a metal original grill but fiberglass hood and fender. It depends on how it all works out.

I think this is a great idea on keeping the weight down! I've seen guys make fiberglass Wheel Horse RJ hoods before and they look really good and once you paint it, it'll look like its factory and nobody will be able to tell its fiberglass. Heck, I didnt know you had a cardboard hood on the adventure edition until you mentioned it!

Thanks. Yeah the cardboard hood actually looked a lot better than I thought it would. It's super light weight though.

I decided to buy some of these tires after all for the rears. Same size as the other tires, 18 x 8.50 x 10. I may also get a tire groover and add a few seips for hard surfaces and rocks ect. Generally I think they'll be better over all but time will tell. I can do some testing. I have steel rims the same size that I can mount the other ones on too.

Lawn Trac R-1's! Whatever that is, but it sounds cool. "yeah man, I got the lawn trac R1's...."

R1s, if you were curious is basically the technical term for the old-school farm tractor tires. They are designed solely for the purpose of performance in loose dirt and mud so I think for your purposes they are an excellent choice.  Hope that helps.

Interesting, I didn't know that. Still sounds cool tho. I was thinking that on hard edges and things, such as some of the rock ledges that are in the TTC, they may not do as good as the knobs. If you imagine a line across the tread of the tire, there's always rubber in contact as it spins. I guess technically there is with the knobs too with how they're staggered, but with the ag tread it never can get to a point where it has something to grab onto. That's where I was thinking putting a few extra cuts in the tread with a tire groover might be a good idea. I'd kinda hate to hack up new tires like that though. They would definitely do better in loose stuff or mud than the knobs I think. Those knobs are just gonna pack up. As far as looks go the ag treads will give it more of a tractor look vs a go kart look, which I really wanna stay away from. It's bad enough the front and rear tires are the same size.

I'm thinking the ramp you flipped backwards would be a challenge maybe especially wet with those tires?