Question about front vs rear track width for LT suspension

Hi guys,

I'm new to the whole LT scene (coming from years of east coast rock crawling in Jeeps), and I have a potentially really dumb question - I've read thru the LT "intro" threads and a few other threads, and I was wondering if it is normal to widen the front track and leave the rear at stock width? A lot of threads talk about how to build the rear suspension with spring under axle leafs, big shock hoops, etc, but I haven't seen anyone mention what to do about widening the rear track width to match the front. So is it normal to have a smaller rear track?

 

Let me preface this by saying I'm not long traveled.

It's my best understanding that you do not need to widen the rear axle for long travel. You're looking to increase down travel and on a solid axle you can do that as much as the drive shaft will allow you. With independent (front) suspension you cannot just push the arms farther down, you have to push them OUT to achieve the increased travel.

 

That's my understanding as well. In the rear your front leaf spring mount is fixed, and your rear mount is on a shackle (movable joint). When the leaf spring compresses it gets longer to the rear of the vehicle. Alternatively, with the front, when the springs are compressed, the tires move outward from the centerline of the vehicle. Increasing track width on the front gives you more travel as there is a longer "pendulum". Increasing track width on the rear doesn't give you any gains.

 

That's a much better and more educated way of putting it than I did.

Although I would disagree with the track width not giving any gains. It depends on what kind of gains you want. Downtravel? Nah. Flex? Definitely. Primarily because you turn your solid axle into 1 long suspension "arm" (geometrically...) when you flex.

I'd say wider rear track width gives no down travel gains in the traditional "long travel" usage sense. Maybe I'm being overly critical?

 

I don't think he was asking about suspension. Just asking why widening the rear track width to match the front isn't talked about as much? Like how would it drive down the road with the front being 2 or 3.5 inches wider per side then the rear??

 

Like a more "trapezoid" shaped truck? Have you noticed they make "trikes" with 2 wheels on the front end? If the rear was wider than the front the tendency to roll is actually higher. You're more stable with a wider front end as the brakes will apply to the outside corner of a turn and the longer arms will stabilize the ride.

Also: he wouldn't have this question if he fully understood WHY you extend the arms to long travel. PVT Pablo's description of the rear shackle is another thing to really "get" in order for the reasoning to make sense as well.

 

I don't really know what he's truly asking. But was just more so throwing out ideas to his question.

 

Well, the engineering explains why rear track width is not increased with rear long travel. I assume people don't worry about rear track width matching the front because it brings nothing to the table in terms of performance. A cheap way to widen rear track would be to put on wheel spacers, but that in turn increases stress by providing a longer lever. A more reliable way to increase rear track is a longer axle, but I don't think that juice is worth the squeeze as a entire new differential, axle and axle housing along with all the fabrication for it would be some $$$.

 

It does cost lots of money for a fabbed axle. I got quoted from diamond axle just over 5k for a 69 Wms to Wms full floater with a land cruiser 9.5 diff arb locker disk brakes axle 4340 axle shafts and hubs. Not much "gain" other then it's the same as the front width and a lot stronger.

 

Thanks for all of the replies guys. The explanation of having to go wider with the front control arms in order to get more travel makes sense, and that's something I didn't even think about. I should have been a little more detailed with my question, but I was curious if the truck handling is thrown off due to the difference in track width (front to back). I could see the wider front track making the truck more stable as the truck goes over rough terrain, but I assume the truck would have more oversteer with the narrow rear track. When I was younger I used to race shifter karts and a kart called a micro champ, both of which did not have suspensions, so I would adjust rear track width to control over and understeer. If I shortened the rear track by a 1/4-1/2" it would make a significant difference in handling. So now you guys know where my question is coming from haha.

Dan

 

When comparing our LT Toyota's with a LT Ford where the Ford doesn't need to increase front track width to gain suspension travel and the front and rear track width is the same. The Ford's in our group don't get the "wander" effect when going down a rutted or narrow 2-track road. In a narrow 2-track the wider front Toyota's tend to grab the outer edge of the burm and it can cause a wander feel. If the outer edge of both front and rear tires grab the dirt the same it tends to not make the truck wander.

 

ah, that's interesting about the rutted roads. Again, something I would never have thought about!

 

I'm long traveled +2 in the front and to get close to matching the width in the rear I run 1.25" spacers in the rear. Looking down the side of the truck it looks pretty close to matching the front. Wider is better for sidehills and just looks better IMO.

 

Installed the All Pro LT last week and have a few miles on it. They said it would push each side out 2". After we put some time on it and it settled out, Straight edges on both sides, my front came out exactly 3" wider than the back. It didn't seem to affect handling going down the road. All Pro has wheel centric spacers in 1.5" that I'll be putting on next weekend. I have no idea if they're made for serious off roading but I haven't found any info that they aren't. I got them mostly for the aesthetics, just to square up the front and the back. My only prob now is they don't make a flare for the 16 Taco yet so like today, there's quite a bit of mud flyin all over the truck.

 

I'd bet that's weight and alignment at play. A (presumably?) Ford F-150/Raptor (strongly doubting it's a Ranger...) is a lot heavier, probably with larger tires, etc.