Ive been on the fence for a long time, but I'm going to try to get an FToy started fairly soon.

I have a general thread about buggies for trail use in the general tech forum, but I have a few very specific questions better asked here.

My main questions are regarding the frame:

Here in Michigan, all of our frames are rotten from 20 years of winter road salt. So I am planning to build a frame from new box tubing.

1) I am planning to use 2 x 3 x 0.120 wall tubing. Do you see an issue with this, integrity wise?

2) Since inboarding the rear springs is common, would I be better off building the frame itself narrower, possibly maintaining a constant width front to back?

3) Would there be value in increasing the amount of 'arch' in the front section beyond the stock amount of arch in a solid axle frame?

Last question for now:

I have 2 potential transmission to use:

L-52 (would be build into a L-52 HD, if used)
R151F

I have both transmissions, currently I'm using the L52, which I have a Marlin 21 spline MC07 (not a MC07-10) behind it.

The turbo trans obviously is stronger and better gearing, the L52 is going to gain me more rear shaft....


To put this in context, this is a build for very mixed trails(I live near Detroit), sand, snow, forests, some mud, east coast places like tellico & rausch creek, etc. On occasion, I'll have my wife and two young kids with me as well.

For parts, I have a 1985 parts truck, a 1987 5 speed turbo truck, and my 1985 wheeler which will be retired/cannibalized for this, which is an 85 22RE/L52/2.28x2.28, diamond front with pretty much all the upgrades from FROR and Bobby, hi steer, HA, IFS rear, discs, etc. So I have a very heathy supply of parts, except all 3 frames are junk, like all others I see around here.

Thanks for your feedback.

1) 2x3x.120 should be strong enough. If it takes hard hits it definitely could dent though. My stock frame has dented in a couple of spots. I ended up using some 1x1x.120 angle iron on the outside edges of the frame to re enforce it.

2) This is really personal preference. If you are going to have a lower buggy then I would say keep the frame rails further in for a little more clearance. If the buggy is going to be a little higher then it wont come into play as much. The mounts for the rear springs will be strong being under the frame rails and easier to fab, but its really up to you.

3) I would arch it as much as a stock SA frame. There are other limits that you will hit before the frame arch will limit you.

In my experience, the height of a box frame takes up too much usable room. I would go round tube if possible. Big weight difference, too.

Either go really narrow or stock width in the rear. If you go directly over inboarded springs, there won't be a good spot for the shocks. Ideally, you would want to be narrrow enough to put the shocks outside of the frame, but that might make spring mounting a little funky.

If you go with the box, just make sure you arch it high enough to clear everything at full stuff. Maybe just a little higher than the solid axle frames.

For what it's worth, the next big round of improvements to my rig would include gutting out the rest of the stock frame and going round tube.

I would definatly go with the L52HD trans. It's 6" shorter than the rest and strong. Then I would move the motor back 12".

In my experience, the height of a box frame takes up too much usable room. I would go round tube if possible. Big weight difference, too.

Either go really narrow or stock width in the rear. If you go directly over inboarded springs, there won't be a good spot for the shocks. Ideally, you would want to be narrrow enough to put the shocks outside of the frame, but that might make spring mounting a little funky.

If you go with the box, just make sure you arch it high enough to clear everything at full stuff. Maybe just a little higher than the solid axle frames.

For what it's worth, the next big round of improvements to my rig would include gutting out the rest of the stock frame and going round tube.

Thanks for the info.

I'm putting a side-profile of the solid axle frame into cad now, to figure out my design. I might actually lower the arch/rise of the rear section an inch or two, to get more/lower storage space.

I was thinking to use square/rect tube, for each of mounting things like the springs, flat belly, steering box, etc.

I didn't think rect would take up that much usable room, since I need a certain amount of vertical room for the trans/t-case/exhaust, etc to sit between the floor boards and flat belly. I coul dprobably go 2 x 2 x 0.12, though, instead of 2 x 3. There's 28 lbs difference between the two sizes for my plan.

I would think I would have room for the shocks if I put the frame right at outboarded, but I can see what you are getting at in the rear. In the front, my diamond housing is wide enough to let the shocks be mounted further outboard. The rear is an IFS, so maybe there'd be a problem, I'll have to check.

I would definatly go with the L52HD trans. It's 6" shorter than the rest and strong. Then I would move the motor back 12".

Hell yeah. You can get some good uptravel with the axle completely in front of the motor:smokin:

We just put a short dog tranny in a Toy buggy here in the shop. 4 1/2" shorter than a W56, gave enough room to push the motor back a couple more inches and add a rear disco!

I would definatly go with the L52HD trans. It's 6" shorter than the rest and strong. Then I would move the motor back 12".

Interesting, I hand't been thinking of going back more with the motor, was thinking more of the rear shaft.

Is there room to actually go more back (I haven't actually seen an FToy in the flesh..)? I was thinking it'd hit the lower windshield bar.

Hell yeah. You can get some good uptravel with the axle completely in front of the motor:smokin:

cant be done

Or, another idea I was kicking around... since its not comp, use a single dana 300 t-case with 4:1/twin sticks, behind the R151F. (Using an AX-15 tailhousing to make it work).

clockable, gearing would be OK for me to not need duals =shorter, and have front dig capability....

Thoughts?

I love my 300. You can do all sorts of cool stuff with cutting breaks and front digs. Single vs dual case depends on your wheelin style. I have duals (Toy to 300) in my buggy, and loved them at first. Now I find myself using only 1 case most of the time. Put it in double low for really technical stuff or big undercuts that might break something and idle through it. I think I am going to pull out the Toy case and just run the 300. I would put the 4 to 1's in the t case and gear down the diffs a bit more so I have the option of a low gear still.


cant be done


Oh yeah, you're right. I forgot:flipoff2:

I love my 300. You can do all sorts of cool stuff with cutting breaks and front digs. Single vs dual case depends on your wheelin style. I have duals (Toy to 300) in my buggy, and loved them at first. Now I find myself using only 1 case most of the time. Put it in double low for really technical stuff or big undercuts that might break something and idle through it. I think I am going to pull out the Toy case and just run the 300. I would put the 4 to 1's in the t case and gear down the diffs a bit more so I have the option of a low gear still.



Anything I do in MI, I don't need the 2nd case. I use it in places like Tellico or Harlan, though, but I only have stock low ranges, so compound low is only 5.2, which is enough for what I do. With the 4:1 in the D300, and lower first in the R151F, I think this will be OK for what I do, especially since the 22RE is getting a crawler cam, header, and lots of tune up(its bone stock 100k miles right now). It'd save a few more inches of drivetrain, and 30-40 lbs of weight with no doubler.