ravencr

Hey Bruce, how's the 3-link system you were working on coming along? I'm looking to do a 3-link myself, and was wondering how yours was progressing?

Chris

Mad Chemist

C'mon Bruce, that's hardly level ground, you've got two corners that are almost completely unloaded, so of course you'd expect good stuff and extension on opposite corners.

I'm not arguing that IFS doesn't flex, I'm just addressing a difference between SA and IFS. "18" of travel" on either a SA or IFS rig does not mean that they will flex the same way.

Let's not hijack this thread by another IFS vs. SAS debate....

SEAN_at_TLT

Claiming to get 25" of travel with either a bolt-on IFS or SAS is ridiculous! You guys all need to clarify that when talking travel there is both articulated and vertical to take into account. The longest travel bolt-in IFS Toyota kit (ESB Fabrications) pulls 18" of VERTICAL wheel travel. This means that each front wheel has the ability to move 18" straight up and down and since it is IFS, hypothetically that means one wheel can be as much as 18" higher than the other at the same time or they can both be fully tucked up into the wheelwell. Now with realistic spring rates it is hard to get that but it does flex very good none the less. For anyone with an SAS to claim 25" of travel then there had better be at least 25" from the top of the tire to the underneath inside of the fender and or at least 25" of clearance from the diff. to the oil pan and you better have at least 20" long shocks. An easy way to quickly estimate the travel an SAS rig is getting is to find out what stroke shocks it is using. SAS's (with shocks mounted to the axle not to a link) pretty much are a 1:1 ratio so if it has a 14" shock it is most likely getting no more than 14" of VERTICAL wheel travel. Since IFS can leverage a shock you can pull easily twice as much travel out of a shock. Total Chaos kit uses an 8" stroke shock to get 13" of travel for example. To claim that IFS is weaker due to extreme CV angles is also bogus, to get more travel out of IFS most kits simply widen the track width, this just takes the existing angles and lengthens them (not increasing them). By placing the wheel farther away from the pivots you can achieve more wheel travel. It is on the other hand completely valid to argue that there are way burlier axles and misc. components available for most live axle housings compared to wimpy CV's. CV's break and that is the downfall of IFS right now. If an easily obtainable D60 strength equivalent were available it would make this conversation mute. But in the end yes, SFA's are better for very, very low speed, very tech rock crawling. However they can compromise on road handling drastically (especially considering most SAS's are "backyard" jobs and most IFS kits are engineered, mass produced [and insured by their manufacturers]) and actually improve on road handling/high speed off road AND work very well for all but the gnarliest of gnarly trails. I say this with confidence and experience. Now a properly built 4-linked, coil-over SAS'ed 4Runner......

crawler#976

Shock travel vs. flex- two totally different concepts for sure.

For my 87' SAS'd P/U, I have 14" travel shocks up front. With bumpstops set to let the front springs arch approx 1" negative, I have 13" of usable vertical travel. The up travel is approx 6".

The rear 12" travel shocks are setup /\ and only have 4" of up travel. There are no bump stops set for the rear- the flat bed rail stops upward flex at about 8".

Combined together, the flex is outstanding- over 36" for the front, and about 30" for the rear. Stability is good too. The ride quality is outstanding- I fly over most FS roads. The front is softer than the rear, but not by much. Good shocks would make it better yet- I'm using Rauncho RSX's up front and Doeschtech's on the rear. Bilstiens would make a definate improvement.

It is not as smooth as a long travel IFS. But then again, I don't live in an area where I can drive much over 65 MPH on FS roads safely. I've hauled out at the dry lake bed at the Hammer's tho- and it eats up the whoops just fine

Cougarfreak

[QUOTE=crawler#976]Shock travel vs. flex- two totally different concepts for sure.

"For my 87' SAS'd P/U, I have 14" travel shocks up front. With bumpstops set to let the front springs arch approx 1" negative, I have 13" of usable vertical travel. The up travel is approx 6". The rear 12" travel shocks are setup /\ and only have 4" of up travel. There are no bump stops set for the rear- the flat bed rail stops upward flex at about 8". Combined together, the flex is outstanding- over 36" for the front, and about 30" for the rear."


Say what? I'm no math wiz, but when does 13" of useable travel turn into 36" of flex?... help me understand the math. how does one calculate the flex?

And 44Runner, what springs are you using to get 25" of travel? Coils or leaf? How long are your shackles if leaf?

Breezey

Cougarfreak,

It done yet?

44Runner

[QUOTE=Cougarfreak]I'm not sure why this is a hard concept. Sure 14" travel shocks will give you 14" of travel straight up and down with the axle level. When you are talking flex (articulation), the wheels are mounted well outside where the shocks are. If you have one shock fully extended and one fully compressed there is 14" of difference between where the shocks are mounted, but 25" inches where the wheels are mounted. If I had a longer axle (current is 60" WMS-WMS) it would actually give the effect of having more measured flex because the wheels would be mounted even farther out.

crawler#976

Flex is more about the combination of front and rear suspention compontents working together, and the pivot points (like front bump stops) of the axles. It's one of the biggest advantages an SA rig has over an IFS setup.

Getting the most flex is kinda trial and error- changing bump stops, shock locations, moving shackle hangers or using longer or shorter shackles all effect flex. To get the most rear flex, I ended up moving the rear hanger forward 2" from it's original modified position and extended my rear shackles 1-1/2" for a total length of 8" between bolts. Rear shocks were originally in the stock positions, now they are /\ with the outer ends right at the spring pack, and the upper mounts about 4" apart in the center. It made a huge difference in how much the rear axle would rotate around.

The front flexed real well from the start- in fact, I ended up lowering my bumpstops almost 2" because the springs arched so far negative. The axle rotated so far upward, the hi-steer compontent hit the frame- not a good thing.

I was really surprised at how much the springs settled after the first few trail runs. The truck dropped almost 4" total, and that changed everything- I'd allowed about 1-1/2" when I measured shock placement, bump stops, etc.

later

smr4runner

Hey all.

Talk about a major highjack. Almost a whole page and nothing mentioned about

CougarFreaks progress.

Maybe this conversation should be moved to another thread. Just my .02

BruceTS

Ironicallly my set-up has out performed many SA rigs..... Actually the rigs that have done better, were all lifted much higher, so they had greater breakover clearance. In the sense of a purpose built rockcrawler SA will always be better, but they are very prone to rollover when sideways.

The issue of shock travel vs. wheel travel, the amount will vary between vertical and articulated. The determining factor is shock location on the axle and what angle it's mounted at. Articulate travel will always be greater, that's why 44Runner gets so much out of the front. Even though I haven't seen his rig in person, I've seen photo's of his front stuffed and drooped. The biggest problem with his rig is the rear doesn't flex that well, in fact mine flexes better than his.

Technically speaking, IFS doesn't flex at all, it has travel, but in a sense it can be made to work similar, the difference is in the amount of weight distributed between the wheels is different.

RTI ramps aren't a good determining factor on how well a rig will do, you have to take it on the trails and test it. What I have found out is the 3rd Gens have a breakover clearance problem, namely the 2 crossmembers and fuel tank. An easy fix is to SAS and lift it.

Cougarfreak

This week will see me working on the details and getting it running for this weekend... in theory. I'll keep y'all posted.

BruceTS

I did some measuring finally! this photo is with my rig fully drooped, with my limit straps preventing further drop, as for compression the top of the tire will compress all the way to the bottom lip of the fender. So I measured from the top of the tire to the bottom lip and got 15 1/2"! The only thing I can figure is because my tire size and they stick out a bit further is the reason for the higher numbers, In other words as the wheel droops it goes negative camber and under compression it has more positive camber, with the larger diameter tires and width the numbers reflect this result.

Mikronized

I really want to check your rig out at pismo.

Cougarfreak

Well that theory got shot right out the window... I am however out of the garage and driving... Sans shocks so the ride is quite bumpy. It drives like a champ though. Marlin crawler works clutch works steering works... all of the essentials are in working condition. I still have to notch the tranny Xmember, and build shock hoops to attach my shocks. Those are my evening projects for the next couple of days. I hope to have it 4x4 by this weekend so I can test it and join the Take Over crew Monday to Wednesday!!! I have a few new pics on my site so check it out.

justinh

do you think you measure more travel because your fenders have much more clearance than a factory fender or possibly the fiberglass they used to determine their numbers?

BruceTS

Actually the proper way to check travel is measuring from the center hub. The fenders has nothing to do with the way TC got thieir numbers, I was just curious what the physical travel really was, since I had never measured in that way.

Personally I would have perfered factory fenders, but the work involved in modifying them was more than I was willing to attempt. If I keep tearing up those fiberglass one's, I may just go ahead and reshape my stock one's to fit.

justinh

thats cool, i was just wondering since you were measuring droop.

Jboy

Awesome job there! I have ? about your previous setup. In this pic how long is the strap and where are the ends attached?

Cougarfreak

I have installed my King 2.5" shocks 12"stroke in all 4 corners and am going to place my air bumps this weekend. I've placed the shocks and hoops according to full droop, but when at ride height there is only about 3" of up travel for the front shocks. The air bumps i'm using have 4" of travel to them so I'll be riding on my front bumps the whole time. When I measured my travel using a floor jack and big ass ratchet strap on the front axle and a hilift at the opposite rear corner, I measured about 11.25" of total travel. I know real world wheeling is different than a couple of lifts in a garage, I guess I'm questioning my travel selection on my shocks. 14" shocks will need to go higher into the wheel well, but I'm not sure how much higher the axle will go without hitting frame/oilpan/steering. should I consider 14" shocks that I don't think i'll get full travel out of, or not worry about the up travel and love the droop and stick with my 12" strokers? I am planning on using this vehicle for the desert prerunning for a race friend of mine, and for rock crawling.

I also noticed the tail end of my YJ rear leafs i'm using in the front are sagging. (axle to front hanger of the spring flat, axle to shackle of front spring negative arch) the front of the spring has two brackets holding the spring pack where the rear only has one, which I figure is why the arch difference. Are the springs shot? I didn't see a whole lot of springs used other than 44044's and I know those are way too arched for my application, but i thought I'd throw this question out there anyway.

Cougarfreak

I don't remember the length of the straps, but Downey sent them with their 2.5" kit. I wanna say 12", but I'd call Downey to ask them for sure. The lower part of the strap just uses the bolt from the bottom of the shock, and the upper requires a tab to be welded to the frame. Mine was welded on the outside of the frame right under where the tube Xmember comes through the frame. a bolt then attaches the strap to the tab.