How low on ttb?

[TexasRebel]

I was doing some talking with my dad last night and we were throwing some ideas around. We thought about building my Ranger into a awd course racing truck just for the hell of it. The main problem we thought of was the ttb. My question is, how low can you get a ttb setup?

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[adsm08]

I would not try to build a TTB truck into an AWD. The problem there is that the front axle shafts use U-joints. Every AWD I have ever seen used CV joints, at least on the front.

The reason is that U-joints work best between 1-3 degrees. Less than that and they get flat spots on the needles, more than that and you put too much stress on the cross and ears. When you are steering you can have those front joints operating past 45 degrees. And the faster you are going the more pronounced the issues from stress become.

A CV joint can operate smoothly from zero degrees right up until the axle touches the cup.

Get a regular swivel for a ratchet and put it on an air tool, then operate it at an angle. Then do the same thing with a impact swivel. This will demonstrate the principles at play here perfectly.

 

[TexasRebel]

I would not try to build a TTB truck into an AWD. The problem there is that the front axle shafts use U-joints. Every AWD I have ever seen used CV joints, at least on the front.

The reason is that U-joints work best between 1-3 degrees. Less than that and they get flat spots on the needles, more than that and you put too much stress on the cross and ears. When you are steering you can have those front joints operating past 45 degrees. And the faster you are going the more pronounced the issues from stress become.

A CV joint can operate smoothly from zero degrees right up until the axle touches the cup.

Get a regular swivel for a ratchet and put it on an air tool, then operate it at an angle. Then do the same thing with a impact swivel. This will demonstrate the principles at play here perfectly.

Hmmm. I wonder what kind of setup I could get to put under it. I'm not afraid of fab work.

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[adsm08]

I think the best bet may be to just swap the body on to a 98+ frame.

 

[TexasRebel]

How about a narrowed solid axle?

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[adsm08]

Depends on the axle.

Some Jeep Dana 30s use CV shafts already, and are pretty close to the right width.

The real key is to stay away from anything with U-joints.

 

[TexasRebel]

I'll do some looking into it. It's not a definite plan yet, but it sounded different and interesting.

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[alwaysFlOoReD]

Another problem with the ttb is "jacking". When going thru esses the front end axles start climbing [ sorta best description I have ]. Kind of like scissors, if the one tire is planted the truck rolls and the opposite tire gets closer, and then you switch direction quickly and the tires haven't had a chance to spread apart yet and get even closer to each other. This raises the front end, so also the center of gravity, and makes it easier to roll....not good, ask how I know.
If I start over with a new to me ford truck, it'll be a sla front. I'm doing similar to short course offroad type racing with a 91 Ranger. Pretty much all the trucks I race against are solid axle or cherokees. It's not all bad as the ttb takes jumps good.

 

[TexasRebel]

Another problem with the ttb is "jacking". When going thru esses the front end axles start climbing [ sorta best description I have ]. Kind of like scissors, if the one tire is planted the truck rolls and the opposite tire gets closer, and then you switch direction quickly and the tires haven't had a chance to spread apart yet and get even closer to each other. This raises the front end, so also the center of gravity, and makes it easier to roll....not good, ask how I know.
If I start over with a new to me ford truck, it'll be a sla front. I'm doing similar to short course offroad type racing with a 91 Ranger. Pretty much all the trucks I race against are solid axle or cherokees. It's not all bad as the ttb takes jumps good.

I'm thinking more of road courses. Might set it up to where I could throw a couple inches of lift on it so I could do off-road racing too.

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[alwaysFlOoReD]

Well, if you look at one axle from the front, and imagine the spring as a fulcrum, you could lower the side opposite the tire and that would lower the frame if the spring and tire stayed the same. So adding a lift without the lift springs would lower the truck.

 

[TexasRebel]

Well, if you look at one axle from the front, and imagine the spring as a fulcrum, you could lower the side opposite the tire and that would lower the frame if the spring and tire stayed the same. So adding a lift without the lift springs would lower the truck.

If it came down to it, I could have 2 sets of springs for it. I wouldn't be switching them often.

Sent from my Samsung Galaxy S3 using Tapatalk.

 

[4x4junkie]

I would not try to build a TTB truck into an AWD. The problem there is that the front axle shafts use U-joints. Every AWD I have ever seen used CV joints, at least on the front.

The reason is that U-joints work best between 1-3 degrees. Less than that and they get flat spots on the needles, more than that and you put too much stress on the cross and ears. When you are steering you can have those front joints operating past 45 degrees. And the faster you are going the more pronounced the issues from stress become.

A CV joint can operate smoothly from zero degrees right up until the axle touches the cup.

Get a regular swivel for a ratchet and put it on an air tool, then operate it at an angle. Then do the same thing with a impact swivel. This will demonstrate the principles at play here perfectly.

Most domestic trucks during the 1970s had AWD (or "full-time" 4WD) with a u-jointed front axle. For sure you do feel the elliptical nature of the u-joints when you're turned sharp, but the center diff in the t-case dulls it down a good bit, especially if you have an automatic trans.

I don't see a problem with running an AWD setup on a TTB axle except for one critical point: the center u-joint on the TTB (something the '70s truck didn't have). That u-joint will have to be perfectly straight (no angle on it) at ride height. If the suspension sits at any attitude that maintains more than a degree or two angle on that joint, you will feel that as you go straight down the road at speed.
There's info about the ride height of TTB suspensions here (scroll down a ways):
http://www.therangerstation.com/Magazine/winter2008/steering_tech.htm

This means stock height will be the lowest you'll be able to get it in any practical sense. For anything lower, no doubt I would agree the SLA IFS setup lends itself a lot better.

Another problem with the ttb is "jacking". When going thru esses the front end axles start climbing [ sorta best description I have ]. Kind of like scissors, if the one tire is planted the truck rolls and the opposite tire gets closer, and then you switch direction quickly and the tires haven't had a chance to spread apart yet and get even closer to each other. This raises the front end, so also the center of gravity, and makes it easier to roll....not good, ask how I know.

I would venture a good guess that's something coming from your steering. I haven't experienced that at all on either of mine (but wow I sure did on a friend's truck not used to driving it... It had a major steering angle issue which has since been fixed).

 

[bobbywalter]

i dont see an issue with the ujoints either. as long as there is a diff action in the t case the joints are not too noticable on the pavement, many may not even notice at all...


there was a brawler that ran downriver and detroit area that was lowered a bit. they had to cable it down in the front to launch good, it was around for quite a few years. it was about like a beat down 2wd in ride height. low for a 4x4. there was that one and a s10....years later i found out both had the same group of owners and powertrains.

put a reg cab on a awd v8 explorer chassis and call it fun.

 

[alwaysFlOoReD]

@ 4x4junkie;
Perhaps, I'm always learning and wiilling to learn. This is on my race truck which is a very low buck attempt. Using a 91 rollover I put an 87 stx hirider lift on it and checked/replaced worn suspension and steering parts. At the time I rolled it I had just come thru a sweeping off camber right hander into a slightly tighter off camber left turn and immediately a hard right hairpin. I rolled at the apex of the right turn. There was no sign of a rut to catch the tire in. It was hard pack dirt that had been grass previously. I was driving at the limits of my ability and was trying to catch a competitor. I believe what happened is as I described in my previous post. I don't think it's something most people would run into as it is a fairly narrow set of circumstances that will cause jacking, namely at speed thru esses and the hairpin was the straw. If I was on pavement with sticky tires I believe the same would happen until I [hopefully] learned the limits of the truck and myself.
@ bobbywalter;
I've also thought of a ranger on the newer explorer with full independent suspension.

Richard

 

[bobbywalter]

@ 4x4junkie;
Perhaps, I'm always learning and wiilling to learn. This is on my race truck which is a very low buck attempt. Using a 91 rollover I put an 87 stx hirider lift on it and checked/replaced worn suspension and steering parts. At the time I rolled it I had just come thru a sweeping off camber right hander into a slightly tighter off camber left turn and immediately a hard right hairpin. I rolled at the apex of the right turn. There was no sign of a rut to catch the tire in. It was hard pack dirt that had been grass previously. I was driving at the limits of my ability and was trying to catch a competitor. I believe what happened is as I described in my previous post. I don't think it's something most people would run into as it is a fairly narrow set of circumstances that will cause jacking, namely at speed thru esses and the hairpin was the straw. If I was on pavement with sticky tires I believe the same would happen until I [hopefully] learned the limits of the truck and myself.
I've also thought of a ranger on the newer explorer with full independent suspension.

Richard

i prefer to run "over center". so with them scissored up and the center joint in a bind.. but you need all the clearance help you can get for shit hole muddy rutted trails. when you do that the jacking can be more pronounced but usually more predictable in my experience on the road. under center rides way better, but if you go over center the toe in radically jacks the truck.


but. if you have a k link or other improved steering over stock these problems are very minimal if there is any issues at all.