CDN M101, 33" Tires and SOA -- or NOT?

[greentruck]

I'm thinking a little ahead as my new wider fenders are fabricated. Our CDN M101 is already set-up with 6x5.5 hubs and is currently running some old 28" Goodyears on FJ60 rims.

I measure 3 1/2" between the bottom of the bumpstop and the top of the spring, but realize that a hard bump could give a bit more travel depending on how much the bumpstop rubber compresses.

There is currently 6 1/2" from the top of the 28" tires to the underside of the fender. So I calculate this gives about 3" of minimum clearance to the fender bottom with the current tires and suspension, depending on compression of the bumpstop.

Eventually, we plan to run 33" BFG MTs on our 80 and do the same on the trailer. This means that the tires will use up most, if not all of the 3" under-fender clearance that the current suspension provides on top of the tire.

So this would be darn close to using all the extra clearance under the fenders in stock configuration with the axle on top of the spring. The wider fenders will be smooth, all new metal from the body to the outside lip, where they will have a 1" angle welded on to stiffen them. There will be nothing to snag underneath where the tire can potentially contact the taller tire.

Has anyone run this particular configuration that has experience? Should I go with ahead and plan on a preemptive spring-over-axle? Or should I just see how it goes, because it's unlikely to be more than minimal contact in any case? I actually prefer to keep the lower center-of-gravity in the stick configuration, given the sidehills we encounter.

I ask, because we head over the passes in Colorado where this is likely to first get really tested. I'd hate to get somewhere where I'd have to make a 250 mile detour or, worse, get stuck with tire damage just to get off the trail. I kind of doubt the worst case scenario, but figured I'd ask...and get some opinions;p

 

[Panzer]

Mike,
Heres my 0.02,
I have a CDN101 that I pull behind my 80. I have taken the 101, in the full stock configuration on my last three CO trips. (Every year for 2 weeks first part of August) Call it a total of 30 days of offroad expedition tripping all over the SW CO named trails. Loved it, and loved it low and stock.
I recently picked up a pair of 80 wheels and mounted the best 2 of my old 80 tires (315's), I swapped the hubs out using the Northern Tool hubs that match Toyota lug pattern. To mount these to my trailer and clear the stock fenders I did the SOA swap. basically it works out to about a 5 inch lift. It pulls fine and looks ok but I don't like it, too tall for Colorado trails, too tippy in my opinion. One of my traveling companions uses a 416 that is SOA on 35s and he hasnt flipped it yet but too close too often for my comfort.
I plan on switching back to SUA, doing a 1-2 inch shackle lift and modifying fenders to bring the CG back lower. I am also going to switch from the current 315 tire (35") down to a 255 (33").
Matching my trucks 315s is nice in theory but in reality the difference in rolling resistance and weight is worth more than the untility of matching all the wheels and tires. Truck has its spare, the trailer has its spare, if I get real worried I'll opt to carry a spare spare for the truck.

The stock wheels and tires on a 101 are roughly 30" tall. The OEM wheels have a huge backspace which is why the tires are full covered in the stock configuration. With aftermarket wheels the tires will stick out quite a bit but it sounds like you have that plan covered by building your own new fenders.

Since your planning on 33 tires and doing your own fenders I think that you could definitely go no lift and have no problems by simply mounting your new fenders a little higher than the OEM ones.
In fact other than the width/tire coverage problem you could most likely run no lift (or a small shackle lift) with the 33 tires you want by trimming the lowest square part from the stock fenders and still be ok. I dont have the pics on this computer but I will try to get some pic of my set up posted tonight along with the pics of my fender trimming.
Any other Qs just ask.
Hope this helps,
CAS

 

[d0ubledown]

im running 295s, a SO on 80 wheels. its a bit tall, but not overly tippy or top heavy. ive also taken it out with SO & stock wheels & tires. put it this way, the SO costs nothing, and is easy to put back to stock...so theres no reason you cant try both.

ive seen some with 33's & SU, and it seems to work OK. the suspensions in these things dont really articulate or move, unless you have 1000s of lbs of weight in it. we use it for camp gear, probably 1600-1800lbs gross, with the trailer itself about 1100 of that. try it out both ways.

im sure a SU lift can be done easily. wonder if a block setup might even be plausible...or a simple shackle lift.

ive taken mine through some mild stuff, some off camber, no issues. another reason i wanted to SO it was so it sits level with the truck, and i can actually see it with the lid on. i cant stand towing something i cant see behind me. i dont use a receiver hitch, got the pintle bolted directly to the oem location, and with my 4" lift & 315s...it sits pretty high. just recently put the lunette ring up top. should be nice n level now...

 

[Brentbba]

I haven't had my M101 CDN out on the trail yet. Got it in December and repainting it slowly. It's got the SOA and running on 255/85/16's (35's). It does sit high.

In these two pics, you can see the clearance of the SOA on these tires. There's 9" clearance from the bottom of the fender to the top of the tire. The fenders have been extended out from the body about 3" to cover the tire, but it's the original fender. The trailer top rail sits a full 50" off the ground with the SOA.

I can only say it towed very easily empty the 200 or so miles home when I picked it up.

Let me know if you want any other pics or measurements.

 

[Panzer]

im sure a SU lift can be done easily. wonder if a block setup might even be plausible...or a simple shackle lift.

A shackle lift should be easy. 1 inch longer shackles are at Northern Tool for $4.95 per pair or if your like me you have random parts from 4-5 old leaf spring lifts laying around the garage you can test various shackles until you get the lift you want.
I said should be easy because that was my original intent until I tried to get the original shackles and pins off the trailer. 2 hours later I decided that SOA was going to be faster than fighting the shackles. (I had a departure deadline for a camping trip)

 

[greentruck]

CAS,
Darn, I forgot all about tires being as wide as they are tall??!!!???

Thanks for kicking off discussion on this and I can clearly see that more heads are better than my brain. I was all worried about vertical travel and forgot all about accommodating the width of the tire. But I'm good. It's just about exactly 35" between the two end tabs and even in stock configuration the widest part of the tire through the axle center should always be below the minimum measurement. So I dodged that bullet and the new fenders will still work.

Brent,
Your pictures illustrate the relationship of the SOA suspension and mounted tire to the fender very nicely. I'm curious to know how much you've gained with your SOA. Is it basically the same 5" that Panzer gained? And if you measured down 5" from the front and back lips of the fender, how much clearance do you have to the tire?

Sonny,
From what you and others have said, I'd agree that the suspension gets relatively little movement on these in stock configuration. Eventually, I want to have an onboard water tank and will probably carry some fuel, but the biggest other item will be a RTT.

Thanks everyone for helping start to thinking this through. Panzer's experience in SW Colorado is exactly what I'm building for, so I can understand his misgivings about the SOA route and he knows why I'm asking. Serious switchbacks and elevation changes and the worst of it is often what you want to go over to set up a new base camp so you want to bring the trailer with, rather than return to it at the end of the day.

It does look like it's worth trying to squeeze the 33" tires under the trailer with the suspension in stock form. The fender can be adjusted to gain an inch of so, if needed. More than that is probably not needed.

The truck's pintle hitch is mounted to the rear bumper four-bolt OEN hitch point. The lunette is currently in the upper-most hole on the trailer. And I am more interested in what works right than in getting the exact same wheels all round, but I'm feeling pretty good about getting it looking good now.

 

[Greg_B]

I would echo CAS comments. My time with the trailer on the trail is not as extensive, however it has confirmed for me a few things at this point.

a) I want to stay SUA. Will move the fenders up to accommodate a max 35" size tire.

b) I will to maintain a narrow axle width, relative to the tow vehicle. Threading the needle on narrow trails and the combination of short trailer tongue and narrow axle width lets you forget the trailer is there: get the vehicle through, and the trailer will stay inside those lines.

c) At this point the stock tongue length will be maintained. Pain to back up, but off road makes up for that.

d) I will go with trailer brakes at some point, which means a new axle, matched to the the Toy lug-nut pattern. See (b) for max width it will be.

e) I had it twisted up pretty good a few times, and was running the stock sized tire. There was never really a clearance issue (did bang up some trailer lights I had thrown on, but thats a location problem easy to solve when new fenders are built).

So my vote for running 33's would be stay SUA, and raise the fenders to accommodate.

hth's

gb

 

[greentruck]

Greg,
More good advice. Thanks!

a) I'm pretty sure that I can use the stock fender mounting points with a 33" tire, but it will be close. Sticky mud would be a problem with the limited clearance, I suspect. 35" will go, but I may want to lift the skirts on the 33" up there just to get the extra clearance with them. We'll see.

b) I was thinking about a taller replacement near to stock width, but then it's no good as a second spare and that's all antique stuff pretty much anyway. But the good news is that the trailer track width is 63", while the 80's is 74". It won't be like OEM in relative narrowness, but I agree that there's no need for it being any wider than it will be with 16x8 FJ wheels on it.

c) Yeah, I was thinking the same way, mostly because I don't want to engineer something longer. But I plan to do some checking of clearances just to see how close things end up. This has me wondering if there are longer lunette castings that will fit our CDN M101? That would be easy, if it's possible, for me to do.

d) The M101 uses a parking brake that is the same set-up as a Dexter 10"x 2 1/4" electric drum. I think I saw some old threads about that, but probably can be done regardless.

e) Yeah that's why I plan to do some preliminary testing in c) above.

I'm no good in reverse until I've gotten good and crossed up a couple of times when starting a trip

 

[Panzer]

Better late than never with the pics.
1st is truck and trailer combo. I had to move my pintle ring to the lower hole to level it out. This now interferes with the tire carrier swing arm. I hope with the new springs on the 80 and flipping the trailer back to SUA with a shackle lift and smaller tires that I can get everything to back to level and be in the top hole on the trailer.
2nd shot shows how far out the tires stick with the OEM fenders. As has been posted elsewhere, all it takes is one rock getting flung forward and you could lose the rear window of the cruiser.
3rd shot shows the fenders up close with the square bottom removed.
Compare my fenders to Brentbba's pic posted earlier in this thread.

 

[greentruck]

Panzer,
Never too late to help.

My new fenders are still at the shop, but getting close. Basically 5" wider on each side than the military ones. Your rearview pic demonstrates how those non-standard rims really call for some help with keeping the road on the road.

Your rig is set up pretty much how ours probably will be. Hardtop a la eLeBlanc with RTT. But with a SUA you'll be able to see over the trailer I think. That is one thing I'm trying to get, as well as the all important low center of gravity for Colorado trails. Not so good for stump-jumping but less nervous in the clouds.

 

[d0ubledown]

hey panzer, curious as to why after the spring over your axle seems to have shifted rearwards? or is it just angle of the pic?

 

[Panzer]

Mike,
When it was low and the RTT was off of it I couldn't see the trailer at all. Not in any of the 3 mirrors, which makes backing it up a giant PITA. Low with the RTT on it it was perfect, I could just see the top flat of the RTT.
As far as clearance, SUA with tires matching your cruiser the trailer will have more clearance since it doesn't have a pumpkin. The only contact I ever had on the trailer when it was OEM was dropping off ledges or driving thru ditches. When the rear of the truck would drop off the trailer foot scraped the ground a couple of times and the rear of the trailer slightly scraped as it dropped off the ledge or into the hole. Never hung up and no damage I could just hear it.

DD,
In the first pic it is angle of the photo + the shadow makes it look that way.
You can see in the 3rd pic that it is more or less centered but it really is an inch or so aft of center relative to the box length. If you look at brentbba's pics you'll see the axle in the same place.