Inv4drZm's Build Thread
- Thread starter Inv4drZm
- Start date
Here's the data:
Same bump height for all arms fully stuffing a 35" tire up to the stock fender, but more droop for the longer arms. Unless otherwise specified degrees are toe-in at each tire. Double the numbers for total toe. Stock geometry spindle and rack position stayed the same. Assuming .5* toe in each tire at ride height.
My analysis: Bump numbers are all the same and close to ride-height toe. The more downtravel you have the worse the LC200 rack bumpsteer is. And for the love of Toyota don't put a clevis on a LC200 rack without optimizing the rack position and spindle geometry.
(With a 35" tire, 1* is equal to .6" of bumpsteer. My rookie guess is that under 1* to 1.5* or .6" to .9" is optimal for all driving conditions.)
I ordered from best to worst:
Thanks for getting this laid out, it certainly does help get the visual for the various setups.
I can see this being a huge issue (possibly?) for high-speed desert guys like you mentioned. I have no concerns going with the LT arms and LC200 rack since it looks like on the street it's quite similar to stock, certainly not all too awfully worse.. if I had to guess.. (with absolutely 0 test data to back this up) I would say I would say that I would be very surprised if I saw more than 2 inches of down travel up front during street driving.. my biggest down travel up front on the street comes from taking off on the stoplight if I hammer down, or if I'm cornering REALLY hard (which the TK1 Sway bar in the rear REALLY helped out recently). Obviously I would expect tire wear to be worsened quite a bit if the toe-in is changing drastically with one side approaching near full bump, and the other approaching near full droop (this would be super hard to do with regular street driving on an LT set up?). For rock crawling applications I have no concerns about what each tire is doing as far as toe. I'm never in a full droop or full bump with both wheels at the same time, and in the instances where either is at an extreme, I'm usually lifting a tire, or at least unloading quite a bit of weight off of it.
As far as the clevis.. I can see that being really handy.. but with the numbers that you get with it on top of the additional cost of getting the clevis I would probably lean towards just fabricating my own outer tierod and leaving the inner as is.. that way the factory boot can stay on with no issues as well.
At the end of the day I guess it could also be possible to cut the rack down a bit? Though at that point I would kind of wish I just went with a Tundra rack to cut down to begin with lol.
I don't think my build thread gets much traffic but does anyone think there is a market for fabricated spindles using the factory mounting points? In the $1500 range.
Good option for those with standard LT kits that need more strength.
Sourcing unbent spindles on Ebay:$300
Spindle gussets and double shear tabs: $150
Paying a welder: $250
Total: $700 for alternative
Unfortunately need at least 10 people interested in order to make it work financially.
Like this but for the factory style UCA:
Are you looking to try to get 10 total between factory mount & the modified mount? If I had to guess I would say the 4th gen market would be tough to do..I would imagine you could get 10 folks onboard for a weld-it-yourself LT Arms that use the factory spindle a lot quicker than 10 people to get on onboard for an upgraded spindle.. but I could be wrong. I don't know how many 4th gen guys currently are even on a non-factory spindle outside of just doing the gusset weld-kit and calling it a day.
Inv4drZm
Senior Member
The toe-in bumpsteer from the wider racks starts to kick in just after ride height. So throughout bump it stays consistent but just as the tire starts to droop from ride height the short tie rod starts to pull the tire inward.
I heard you can't easily modify the LC200 rack, the rack ends are a different design than the Tundra rack and not as easily shortened.
Inv4drZm
Senior Member
I believe these spindles would fit any Toyota that is willing to convert to outer heim tie rods ends. So not just 4th gens.
Inv4drZm
Senior Member
If I did group buys it would be feasible to change the hole specs per customer request. But they could be drilled out and retapped fairly easily by anyone with a vice if I made them all m12s.
I thought about making it so some nice Wilwoods would bolt on but those are expensive.
4RunnerAquasport
Senior Member
Hey Mason,Here's the data:
Same bump height for all arms fully stuffing a 35" tire up to the stock fender, but more droop for the longer arms. Unless otherwise specified degrees are toe-in at each tire. Double the numbers for total toe. Stock geometry spindle and rack position stayed the same. Assuming .5* toe in each tire at ride height.
My analysis: Bump numbers are all the same and close to ride-height toe. The more downtravel you have the worse the LC200 rack bumpsteer is. And for the love of Toyota don't put a clevis on a LC200 rack without optimizing the rack position and spindle geometry.
(With a 35" tire, 1* is equal to .6" of bumpsteer. My rookie guess is that under 1* to 1.5* or .6" to .9" is optimal for all driving conditions.)
I ordered from best to worst:
I may have missed something, and I'm probably reaching a little here. Your numbers have a +4.5" Control arm factored in. Could the DK +3.5" arms be a little more forgiving in the BS figures? Or most likely worse w the 200 rack?
I also have the 200 OTEs I could experiment with, or am I way off base w my thinking?
All things aside I'm impressed with your drawings and would love to learn some CAD, and my geometry skills could use a hell of a lotta work.
Thanks
Inv4drZm
Senior Member
I would say its similar to the +4.5" arm numbers, maybe a little worse.
I think the bumpsteer really just depends on how much downtravel you are getting. 12.5" of travel is good for a +3.5" kit, but low for a +4.5". The numbers above are for my +4.5" arms at 12.5" of travel, but they should be capable of 15" of travel.
Anything you can do to shorten the tie rod mounting surface or pivot points will help. Either by machining down the mounting surface of the tie rod ends or machining down the rack ends if possible and installing a tie rod with a shorter bolt or threading the rack deeper.
Speaking of travel, I was going to design my own coilover top hats to mount the shocks a hair above the coil bucket to maximize travel. But I found Fox already makes a top hat for their IFP Toyota shocks that does just this. I got the part number from Fox just need to find them in stock from a distributor or backorder them.
206-06-085 – mount adaptor
214-39-125-2 - spacers
018-04-014-A – bolt
4RunnerAquasport
Senior Member
That Top Hat is a great idea.I would say its similar to the +4.5" arm numbers, maybe a little worse.
I think the bumpsteer really just depends on how much downtravel you are getting. 12.5" of travel is good for a +3.5" kit, but low for a +4.5". The numbers above are for my +4.5" arms at 12.5" of travel, but they should be capable of 15" of travel.
Anything you can do to shorten the tie rod mounting surface or pivot points will help. Either by machining down the mounting surface of the tie rod ends or machining down the rack ends if possible and installing a tie rod with a shorter bolt or threading the rack deeper.
Speaking of travel, I was going to design my own coilover top hats to mount the shocks a hair above the coil bucket to maximize travel. But I found Fox already makes a top hat for their IFP Toyota shocks that does just this. I got the part number from Fox just need to find them in stock from a distributor or backorder them.
206-06-085 – mount adaptor
214-39-125-2 - spacers
018-04-014-A – bolt
I just measured the two OTEs, the 200 is 1.1" shorter than the Tundra. I will have to rig up a good way to measure toe thru the cycle and play around with them a little bit.
I have a fab guy w a good CNC machine, so maybe I can machine and adapt a little.
Figuring out a reliable measurement system for that much travel, will be a challenge.
The shock therapy guys have aluminum plates they bolt to the spindles and use a fork lift to cycle the suspension. Dont have that luxury....
Whats crazy is Devon says he doesnt notice much BS on the FJ at all w the Tundra OTEs.
Although I might be pushing the top speed on my rig to where it could get exponentially worse and send me on a death roll lol.
Inv4drZm
Senior Member
Ah you said outer tie rod ends. I was reading it as inner tie rods. Outers don't effect bumpsteer at all. They don't effect the pivot point distance.
For bumpsteer you simply need to know the distance between tie rod 'ball joint' pivot points or heim pivot points if you have heims. Nothing about the tie rod between those two points matter.
To reduce bumpsteer with a wider than factory rack you need the lengthen the distance between these two points.
4RunnerAquasport
Senior Member
Ah I figured I was looking at this in the wrong way. So the basikbiker tundra rack mod is really the only way to achieve the longer pivot point distance.
Well I do think my placement will be a tiny bit further forward in the frame than the OEM rack, hopefully adding a little length in the equation. But, too much positive caster could negate that measurement.
And Wishbone already took a 200 apart and didnt like what he found as far as modifying it.
Well I keep hoping for a solution to this lol....
Won't know until I get on the cycle and start pedaling SMH.
so we're talking about the inner pivot point of the control arms in relation to where the rack pivot point is, correct? Hence with the wider rack the inner point of the rack is pushed further away from where it should be, effectively shortening the arc length as the suspension cycles. This is the reason it doesn't matter at all what length LCA/UCA combo is, since the relation between these two distances will remain a constant proportion. I'm assuming that is more or less in line the reason of bump steer with the wider racks, correct?
if so... can we entertain the absolutely crazy idea of moving the subframe pick-up points outward??
would this, at least in theory, work? Or am I missing something completely here?
if so... can we entertain the absolutely crazy idea of moving the subframe pick-up points outward??
would this, at least in theory, work? Or am I missing something completely here?
y=mx+b
New member
so we're talking about the inner pivot point of the control arms in relation to where the rack pivot point is, correct? Hence with the wider rack the inner point of the rack is pushed further away from where it should be, effectively shortening the arc length as the suspension cycles. This is the reason it doesn't matter at all what length LCA/UCA combo is, since the relation between these two distances will remain a constant proportion. I'm assuming that is more or less in line the reason of bump steer with the wider racks, correct?
if so... can we entertain the absolutely crazy idea of moving the subframe pick-up points outward??
The pivot of the inner CV in the diff also has to be relatively in line with the LCA pivots. There is some plunge in the inner joint to account for some misalignment between all these, but pushing all this out may lead to trouble with the inner CV.
Inv4drZm
Senior Member
so we're talking about the inner pivot point of the control arms in relation to where the rack pivot point is, correct? Hence with the wider rack the inner point of the rack is pushed further away from where it should be, effectively shortening the arc length as the suspension cycles. This is the reason it doesn't matter at all what length LCA/UCA combo is, since the relation between these two distances will remain a constant proportion. I'm assuming that is more or less in line the reason of bump steer with the wider racks, correct?
if so... can we entertain the absolutely crazy idea of moving the subframe pick-up points outward??
So far I've just talking about the tie rod pivot points and making them further apart.
But yeah the real problem is the tie rod length in relation to arm length. Like you said extending the arms won't make the tie rod pivot points shorter than the control arm pivot points so the tie rod arc will still be shorter than the control arm arc and pull the spindle inwards.
Yeah you could do a 'reverse long-travel' by extending the LCA pivots and UCA pivots from the frame but that would either reduce travel, or make your truck wider, just to avoid buying the modified tundra rack or keeping a stock rack. Not to mention a good amount of fab work needed.
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4RunnerAquasport
Senior Member
[MENTION=582805]aemravan[/MENTION] these damn engineers just keep crushing our dreams lol.
Inv4drZm
Senior Member
Inv4drZm
Senior Member
This is with the stock length rack.
<a data-flickr-embed="true" href="https://www.flickr.com/photos/152291907@N03/51999112857/in/album-72157683431797241/" title="Mzlt vid"><img src="https://live.staticflickr.com/31337/51999112857_646bdbf6ab_b.jpg" width="1024" height="576" alt="Mzlt vid"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/152291907@N03/51999112857/in/album-72157683431797241/" title="Mzlt vid"><img src="https://live.staticflickr.com/31337/51999112857_646bdbf6ab_b.jpg" width="1024" height="576" alt="Mzlt vid"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
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[MENTION=119302]4RunnerAquasport[/MENTION] the sad part is that I am an engineer.. a mechanical one with a concentration in motorsports at that.. lol. But to be fair, that was quite a while ago and my career path has taken quite a turn, more towards project management than any sort of engineering.. now I'm back to being not so bright haha.
Oh well... stop throwing out reasonable answers at me... I'm dead set on widening the pick-up points on the LCA, cutting down the lc200 rack, and living my best life. lol. Jkjk..
That's a solid point on the tundra rack.. I mean hell.. if you do the disassembly yourself, depending on what you spend on the rack and seal kit you may not be in it for all THAT much money. Just hate that I already sourced the LC200 rack and the offset bushings for it.
I don't NEED the long travel.. but I really want it.. lol. I'm not a dune racer.. and kind of am thinking that if I just don't do the clevis route (which saves me 400 bucks anyway) I could get away with living with the added bump steer since it isn't all that terrible at full bump, and decent at ride height. I'll just need to slow down more around turns so I'm not drooping the wheel down much
All in all, I keep going from "damn.. I thought I could go LT fairly reliably and cheap" to "damn it.. now its more expensive than a proven SAS swap"
Maybe what I need is just a budget LT arms with the stock, gusseted spindle and the LC200 rack once the factory one goes out.. this way I can at least somewhat reliability run 37's
Oh well... stop throwing out reasonable answers at me... I'm dead set on widening the pick-up points on the LCA, cutting down the lc200 rack, and living my best life. lol. Jkjk..
That's a solid point on the tundra rack.. I mean hell.. if you do the disassembly yourself, depending on what you spend on the rack and seal kit you may not be in it for all THAT much money. Just hate that I already sourced the LC200 rack and the offset bushings for it.
I don't NEED the long travel.. but I really want it.. lol. I'm not a dune racer.. and kind of am thinking that if I just don't do the clevis route (which saves me 400 bucks anyway) I could get away with living with the added bump steer since it isn't all that terrible at full bump, and decent at ride height. I'll just need to slow down more around turns so I'm not drooping the wheel down much
All in all, I keep going from "damn.. I thought I could go LT fairly reliably and cheap" to "damn it.. now its more expensive than a proven SAS swap"
Maybe what I need is just a budget LT arms with the stock, gusseted spindle and the LC200 rack once the factory one goes out.. this way I can at least somewhat reliability run 37's
