Proffitts 4-Link - OOPS (1 Viewer)

[Mikesta]

I think its an oops. I have 33" tires on my cruiser now (just rollers) and plan to run 37's.

I think we tacked the links in too far back. The instructions say for STOCK axle placement to remove the crossmember. Otherwise it isn't needed.

Can someone look at these pictures and tell me where I went wrong? I think I relocated my axle 1' back instead of the 6" kit I ordered.

I like it back there.... but don't know if it would work... doh!

With 36's or 37's I'd be able to back up a wall.

I called proffitts and they are moving this week! DOH!

 

[nckrsamford]

it will work as long as you get your drive shaft lengthened and you will have to radial your fenders, most likely competition style.

 

[nckrsamford]

also, what are you going to use as suspension( coilovers, coils, 1/4 eliptical? depending on all of them you may have clearance issues. the frame rails of the fj go from narrow to wide if you look at the front of the frame to the rear. if you run coilovers you may have to notch out the outside of the frame and then reinforce it or run them from inside the frame rails from a cage xmember. coils and buckets you shouldnt have too much trouble with and also the same with 1/4 eliptical. just on the last two check your backspacing and tire clearance of the frame

 

[Senor Aguas]

Call Proffitts and ask them (show them the picture). Then tell us where you went wrong.

 

[zornff]

Did you specify your desired wheelbase ? How long are your links ? In the stock location the bolt that goes through the inner link bracket goes into the hole where the x-member is if you remove it. Thats where i mounted mine originally, the control arms were 36" overall (- heim), this and front spring flip gave me 105" wb. I'm running 1/4 elliptical so the frame wheel well location was not an issue, But i did have to comp cut the tub. HTH.

BTW, Proffitts is moving to a new location and might be hard to reach for a bit.

Mike

 

[Sputnik40]

I can only comment from observing what a friend has on his 40 - and his looks to be almost that far back. He doesn't have much of a rear wheel well after clearancing - and I think he might of even had to cut off the ends of the rear cross member, but he's running 40" tires.

One problem he had was that due to the rear steer with the lowers mounted on the outside rails - his coil buckets rubbed the tires under articulation - he'd already welded them in (doh). I'd flex it out to see where the tires will be before finalizing anything. Will be a nice wheelbase.

 

[mookie]

leave it long, being able to back up a wall is a good thing!

 

[rusty_tlc]

Won't the axle move forward when you get the springs installed?

 

[Mace]

Won't the axle move forward when you get the springs installed?

not really, the axle will stay where it currently is. the overall travel will have a bit of arc to it, but it will not make that much of a difference at all.

 

[Mikesta]

also, what are you going to use as suspension( coilovers, coils, 1/4 eliptical? depending on all of them you may have clearance issues. the frame rails of the fj go from narrow to wide if you look at the front of the frame to the rear. if you run coilovers you may have to notch out the outside of the frame and then reinforce it or run them from inside the frame rails from a cage xmember. coils and buckets you shouldnt have too much trouble with and also the same with 1/4 eliptical. just on the last two check your backspacing and tire clearance of the frame

Coils

Call Proffitts and ask them (show them the picture). Then tell us where you went wrong.

Doh, I did yesterday before I posted here. CLOSED for the move. I'll definitely do this though before running the beads though. When I talked to them they said I could maybe push it back an inch from the 6" back desired possition... so thats why I ask. It looks to be a foot back. I like it at a foot though....

Did you specify your desired wheelbase ? How long are your links ? In the stock location the bolt that goes through the inner link bracket goes into the hole where the x-member is if you remove it. Thats where i mounted mine originally, the control arms were 36" overall (- heim), this and front spring flip gave me 105" wb.

Mike

I ordered my links to put me 6" back from stock. The instructions say to cut out that cross member only if you remain stock and thats as close forward as I can get it. Maybe they sent me the wrong control arms... if so, I'm stoked!

I can only comment from observing what a friend has on his 40 - and his looks to be almost that far back. He doesn't have much of a rear wheel well after clearancing - and I think he might of even had to cut off the ends of the rear cross member, but he's running 40" tires.

One problem he had was that due to the rear steer with the lowers mounted on the outside rails - his coil buckets rubbed the tires under articulation - he'd already welded them in (doh). I'd flex it out to see where the tires will be before finalizing anything. Will be a nice wheelbase.

Good stuff! Thanks

leave it long, being able to back up a wall is a good thing!

buhhhh yea!

not really, the axle will stay where it currently is. the overall travel will have a bit of arc to it, but it will not make that much of a difference at all.

Do you think the ARC will burn through drivelines? Tcases?

 

[nckrsamford]

i read your build post and it doesnt seem like you know what kinda of powertrain you will be using, you might want to figure that out first so you can get the length of your engine, tranny, and t-case so you will know how long your drive shaft might be. after you have that figured out then you can deal with the arc travel of your axle. i say this because if you are going to use a slip yoke you are going to be limited to the travel of the yoke in an up and down travel, pretty much the same thing with a fixed yoke but some dont move as freely and some work more freely depending on u joints, cv joints, ect.... but with coils a friend of mine used angle iron to make coil bucket extensions off of the axle and installed the frame coil mount on the inside of the frame and he had plenty of articulation and clearance.

 

[Tapage]

Do you think the ARC will burn through drivelines? Tcases?

nope .. anycase as much suspension travel, you need to end in a limit .. limiting strap. There you will take a measurement for your shocks and probable will need a long travel slip yoke to handle the suspension travel on your DS

 

[hicruise55]

Sounds like your not trusting me... Are you afaid of all that travel/departure angle??? Just giving you a hard time Mike!

Like I said on the other post, we cycled the suspension and there was no binding... I think the only issue would be (as stated) the pinion angle, which we took that pipe, use it as a driveline and pointed it to the "ballpark" area. I say "ballpark" being a rather standard location? If u run something like a toybox or 203 planatary ect... its gona change that measurement drastically. I would personally run a Orion... but if you use that splitcase you would be ok too, remember you have quite a bit of adjustability in the hiems- which I adjusted to the middle of adjustment before tacking. With that wheelbase your driveline is going to get longer (good) but I would still definetly use a CV driveline. I do like the idea of possiby inboarding the springs a little by building a crossmember on the frame for the buckets? Other than that... the mounts are in good spots, ie strong part of the frame, angles, ect... It looks AWESOME to me! I'd run it and like I said... i'll trade you my running 40 Aaron

 

[notaf-ingjeep]

Sounds like your not trusting me... Are you afaid of all that travel/departure angle??? Just giving you a hard time Mike!

Like I said on the other post, we cycled the suspension and there was no binding... I think the only issue would be (as stated) the pinion angle, which we took that pipe, use it as a driveline and pointed it to the "ballpark" area. I say "ballpark" being a rather standard location? If u run something like a toybox or 203 planatary ect... its gona change that measurement drastically. I would personally run a Orion... but if you use that splitcase you would be ok too, remember you have quite a bit of adjustability in the hiems- which I adjusted to the middle of adjustment before tacking. With that wheelbase your driveline is going to get longer (good) but I would still definetly use a CV driveline. I do like the idea of possiby inboarding the springs a little by building a crossmember on the frame for the buckets? Other than that... the mounts are in good spots, ie strong part of the frame, angles, ect... It looks AWESOME to me! I'd run it and like I said... i'll trade you my running 40 Aaron

It looks sick to me as well! It is a little different than what I've built, the uppers are a little narrow at the frame, and lowers a little wider. But your axle is in about the same place as mine I haven't got a precise mesurement on my wheel base, but it is roughly 102.5". Just exactly what I wanted, with 35" tires! But I would have been just as happy if it were a few inches longer. There isn't a whole lot more frame than that that though, my tires are almost flush with my stock tail lights mounts, but not quite. I may have to change it alll back there because I will likely rub. If you want my opinion, a 4-link suspension is serious buisness. A lot of work, and a lot of hassle, to build, tune and maintain, especialy compared to leafs. If You want to go through all of that, you'd better get serious about it, and don't f--k around. By that I mean stretch the s*** out of your wheel base!!!! I've had a built cruiser since I was 17 years old. The biggest problem I've had off road in all of those years was it's too short. I been soo close to rolling her right over backwards more times than I can count on a 95" wheel base. Saved by my winch cable is all I can say. Now I didn't by a kit, I built everything other than the heims from scratch. If what you've bought will no longer work, as far as spring mounts or what ever. Get a little creative, if you know where it belongs and was designed to be placed. Build something like a new crossmember or what ever it takes to get it where it needs to be now. I don't know anything about the profit kit but it should be pretty easy to make work. It would suck soo bad to build it and then decide you want more. I really like the idea of over kill, you can find a way to make it street leagalish later. Looks like you have plenty more to do though, good luck.

 

[Mikesta]

It looks sick to me as well! It is a little different than what I've built, the uppers are a little narrow at the frame, and lowers a little wider. But your axle is in about the same place as mine I haven't got a precise mesurement on my wheel base, but it is roughly 102.5". Just exactly what I wanted, with 35" tires! But I would have been just as happy if it were a few inches longer. There isn't a whole lot more frame than that that though, my tires are almost flush with my stock tail lights mounts, but not quite. I may have to change it alll back there because I will likely rub. If you want my opinion, a 4-link suspension is serious buisness. A lot of work, and a lot of hassle, to build, tune and maintain, especialy compared to leafs. If You want to go through all of that, you'd better get serious about it, and don't f--k around. By that I mean stretch the s*** out of your wheel base!!!! I've had a built cruiser since I was 17 years old. The biggest problem I've had off road in all of those years was it's too short. I been soo close to rolling her right over backwards more times than I can count on a 95" wheel base. Saved by my winch cable is all I can say. Now I didn't by a kit, I built everything other than the heims from scratch. If what you've bought will no longer work, as far as spring mounts or what ever. Get a little creative, if you know where it belongs and was designed to be placed. Build something like a new crossmember or what ever it takes to get it where it needs to be now. I don't know anything about the profit kit but it should be pretty easy to make work. It would suck soo bad to build it and then decide you want more. I really like the idea of over kill, you can find a way to make it street leagalish later. Looks like you have plenty more to do though, good luck.

Great read. Honestly have read it about 4 times. I love the kit so far. And agree... overkill is rad. I don't want to run anything less than 36" meats so I may need to add a snap on bumper or something, definitely being creative. I need to look up the Washington state laws for height and all that junk. Now that Aaron helped with this, I feel the rest is all down hill. And in regards to your rework. A cutoff wheel cuts through welds pretty quick. I'm still going to run it by the guys who created it.

1. I don't have the lower control arms in the recommended place. Flush with the bottom of the frame. We ground down the crossmember flush with the frame and used that hole, so its about an inch higher.
2. The Upper crossmembers are supposed to have 1/8" gap between the mounts... we welded them in at about 1/2". I'm sure its not a huge deal, but want to find out what could cause issues. I'm pretty sure it wont.
3. I want to make sure Aarons welds are Kosher. The guy says he can't weld. Well the dude can weld. Not only that but he is a master welder. Learning a ton from him on this build. Its great to have friends like him. I think he should bring that pig over with the rooftop tent and camp in the back yard for a few days.
4. I want to make sure the placement of the upper control arm brackets are in the right place.

Check out the chia build for some purist junk.

 

[hicruise55]

The project is coming along nicely, and thanks for the compliments I dont know about "master though?lol). Let me know when you wana burn those welds in or need any other help Aaron

BTW, I have a driveshaft guy that can get new parts if you cant source one used!

 

[Mace]

the lowers being an inch higher will change the suspension geometry..

 

[bustanutley]

the lowers being an inch higher will change the suspension geometry..

In a large way no less..

 

[BellyDoc]

Maybe this is a moot point because you had the frame set up at ride height and the links positioned relative to that when you were designing but I don't see that here. I just see a frame and an axle being put together. In particular, I don't see the powertrain anywhere. Although the heims are "adjustable", you don't want to run them out a lot, so the lengths of the links aren't going to be a major variable.

Have you addressed the pinion angle?

Once you finalize the frame end mounting points on the links, the pinion angle won't be highly adjustable.

One of the interesting properties of a triangluated 4 link suspension comes from the fact that from the side-view, it's either a parallelogram or some sort of trapezoid variation. If the uppers and lowers are perfectly parallel and the frame mounts are parallel to the axle mounts, then the pinion will point the same angle anywhere in the suspension's travel. If the frame end mounting points are all on the same axis, then the links will look like a triangle from the side and the pinion will point toward center point at all times (or whatever fixed angle above or below center it started at). If the frame end mounting points are MORE separated than the axle end, the pinion will swing AWAY from parallel in the same direction as the travel. On uptravel, the pinion angle will go up, and on droop, the pinion angle will go down.

Your frame end mounting points are very close together and the movement of the pinion angle will therefore approximate the behavior of the triangular side view configuration mentioned above. The pinion will basically point at a nearly fixed angle relative to the axis on which the frame ends of the links rotate. It'll basically always point to a spot near that crossmember that the links are attaching around.
Since the t-case output and the origin of the drive shaft will be forward of this crossmember, this means that the pinion angle is likely to be pointing above the drive shaft, and this will be accentuated with droop.

According to what I've read, with leaf springs you want the pinion angle to be a couple of degrees below the driveshaft angle so that with loading, it twists TOWARD perfect alignment. With a linked suspension though, you have any angle you want because you've eliminated the flexible leaf. The issues all come down to U joint or CV capabilities and strength, driveline strain and vibration, and ultimately, keeping the angles within the range that the joints are designed to operate in.

I *REALLY* recommend that you don't finalize your link positions until you're looking at the output from your transfer case at least mocked up in it's intended position. That way you won't get any nasty surprises about the pinion angle.

 

[SteelArt]

Maybe this is a moot point because you had the frame set up at ride height and the links positioned relative to that when you were designing but I don't see that here. I just see a frame and an axle being put together. In particular, I don't see the powertrain anywhere. Although the heims are "adjustable", you don't want to run them out a lot, so the lengths of the links aren't going to be a major variable.

Have you addressed the pinion angle?

Once you finalize the frame end mounting points on the links, the pinion angle won't be highly adjustable.

One of the interesting properties of a triangluated 4 link suspension comes from the fact that from the side-view, it's either a parallelogram or some sort of trapezoid variation. If the uppers and lowers are perfectly parallel and the frame mounts are parallel to the axle mounts, then the pinion will point the same angle anywhere in the suspension's travel. If the frame end mounting points are all on the same axis, then the links will look like a triangle from the side and the pinion will point toward center point at all times (or whatever fixed angle above or below center it started at). If the frame end mounting points are MORE separated than the axle end, the pinion will swing AWAY from parallel in the same direction as the travel. On uptravel, the pinion angle will go up, and on droop, the pinion angle will go down.

Your frame end mounting points are very close together and the movement of the pinion angle will therefore approximate the behavior of the triangular side view configuration mentioned above. The pinion will basically point at a nearly fixed angle relative to the axis on which the frame ends of the links rotate. It'll basically always point to a spot near that crossmember that the links are attaching around.
Since the t-case output and the origin of the drive shaft will be forward of this crossmember, this means that the pinion angle is likely to be pointing above the drive shaft, and this will be accentuated with droop.

According to what I've read, with leaf springs you want the pinion angle to be a couple of degrees below the driveshaft angle so that with loading, it twists TOWARD perfect alignment. With a linked suspension though, you have any angle you want because you've eliminated the flexible leaf. The issues all come down to U joint or CV capabilities and strength, driveline strain and vibration, and ultimately, keeping the angles within the range that the joints are designed to operate in.

I *REALLY* recommend that you don't finalize your link positions until you're looking at the output from your transfer case at least mocked up in it's intended position. That way you won't get any nasty surprises about the pinion angle.

That is very well put and clear.