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Discussion Starter · #1 · (Edited)
How to get ~14" of travel out of the rear of a Tacoma w/o coming through the bed!


We just finished dialing in the custom rear setup we've been designing for the past few months. We originally designed this kit to work on our project '89 4Runner with a coil-over long-travel front end and 3.4L conversion but it will also work on ANY Toyota truck from 84-2004 with a leaf-sprung rear end including Tacomas. We wanted something that would not come into the bed of the truck and compromise the true utilitarian nature of the vehicle.


In order to achieve our goals we knew that some compromises would have to be made such as placing the lower shock mounts slightly below the axle, so we designed the lower mounts to have integrated skid-plates and double-shear mounting so that they could be dragged over and bashed against rocks all day long w/o incident. We also mounted them as far outboard as was possible for better vehicle stability in corners and to hide them in the triangle between the inside bottom of the tire and the axle housing where they are less likely to get hung up on obstacles. In fact with a spring-under these mounts sit at about the same height as the bottom of the spring pack.



For the upper mounts, we pierced the frame rails just in front of the factory rear cross-member and welded in a 1.75" diameter piece of .120" wall HREW mild steel tube and welded on two sets of custom water-jet cut tabs. We designed the tabs to wrap around just more than 50% of the diameter of the tube to better distribute loads. Unlike the factory mounts, these are double-shear for improved strength. The upper mounts are clocked up as far as can be to still allow clearance for the remote reservoir hoses just below the underside of the bed. The lower mounts are rotated down so that the shock shaft just clears the axle tube on full extension (droop). This design uses 12" stroke shocks, an 8-leaf Deaver Tacoma length spring pack and some custom 4.5" shackles to get almost 14" of usable vertical wheel travel. In keeping with the concept of retaining full use of the bed for cargo, we also designed everything to work around a 33" tire mounted in the factory spare location! The remote reservoirs mount to the new cross-member and are rotated up so they lay flat with the factory rear cross-member. The tire is removed in these pics to show detail but rest assured it fits very well with a few inches of clearance on all sides. We also relocated the factory rubber bump-stops to the u-bolt plate on our custom u-bolt flip kit.

We just mobbed the truck in Baja and it works super nice in all conditions. We ran well over 100 miles of trails ranging from the Baja 250 race course whoop section to the heavily rain damaged trail into Mikes Sky Ranch and then out the back side over to the pacific coast. After some serious "testing" ;) we broke the upper mounts but that was my fault because when I installed the swivel 90º's on the shocks, I accidentally slightly overfilled the shocks (wrong piston depth, oops!) so they were hydro-locking a few inches before full compression. Since the bump-stops weren't being contacted the stress was getting placed on the upper mounts and it sheared the cross bar we welded in to the frame. The prototype design crossbar was .090 HREW so since we were redoing that part anyway we decided to jump up to .120 wall just to be extra safe. We also used a longer tube and pierced both the inner and outer frame rail instead of just the inner for even more strength. I'm sure if I hadn't over filled the shocks that the original setup would have held up fine but we figured why not make it even better since it wasn't much more work.

We might be looking into installing this same setup on a Tacoma to possibly codevelop a kit with an aftermarket parts company in the near future. We MIGHT (big might) be looking for volunteers in case any of you are interested in something like this. We would like to do this to a NICE, tastefully built truck that already has a mid-travel front setup (ie: Donahoe's w/uni-ball arms etc.) and 33" tires. No big body lifts please! IF we decide to do this, the volunteer would only be responsible for the cost of materials including water-jet cut parts, 12" stroke Racerunner shocks (remote res. or not), Deaver leafs (7 or 8 leaf bolt-in Taco pack or triple AAL) and Deaver u-bolts totaling probably about ~$1,000. :welder: / labor would be about one full day. Send me a PM with pictures and a description of your rig. If we decide to go ahead we'll select whomever we feel has the most appropriate truck to showcase this potential product.

We are not looking to sell this (or any) product directly as that is not what we do, but if there is enough interest we would like to possibly consider co-branding it with an existing manufacturer (in fact we already have one in mind and they're interested!) since we feel it is has great potential and there is currently nothing out there like this. We'd hate to see a great design only get used on one vehicle!
 

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You didn't have any issues bottoming out the shock? Looks like a nifty setup, but not enough shaft on the shock exposed. If it didn't bottom out, great! Nice work.
 

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Discussion Starter · #4 ·
We blueprinted everything in Autocad before hand, the shock does not bottom on either end of the stroke. The pictures are at ride height and there is about 5-6" of available compression stroke and another 6-7" or so for droop. Add about 5-10% on top of that for leverage to get travel numbers.
 

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Discussion Starter · #7 ·
A cantilever setup is quite a bit more complicated for only marginally, and debatably better results. A cantilever setup uses triangle shaped links (think: bicycle cantilever brake) that pivot and are attached to the axle housing on one end via a rod and attached to a horizontally (more or less) mounted shock on the other end. Cantilever setups place shocks at an angle they were never designed to operate at (horizontal, 90º) and with a side-load on the shocks, the seals and bushings wear out much faster than a shock oriented normally (vertical or close to it). This is not a big issue for a race truck but for a daily driver it is annoying to say the least.

The additional moving parts make for a more complicated design and more fab time as well. The advantage is that you can design the links to increase the leverage ratio allowing you to use a shorter shock to get more travel. If we were trying to get closer to 20" out of it then maybe a cantilever setup would have been an option but that would have also meant ditching the spare more than likely which goes against one of our main goals with the design and overall direction of this project vehicle.

Hopefully that clears it up... :)
 

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SEAN_at_TLT said:
A cantilever setup is quite a bit more complicated for only marginally, and debatably better results. A cantilever setup uses triangle shaped links (think: bicycle cantilever brake) that pivot and are attached to the axle housing on one end via a rod and attached to a horizontally (more or less) mounted shock on the other end. Cantilever setups place shocks at an angle they were never designed to operate at (horizontal, 90º) and with a side-load on the shocks, the seals and bushings wear out much faster than a shock oriented normally (vertical or close to it). This is not a big issue for a race truck but for a daily driver it is annoying to say the least.

The additional moving parts make for a more complicated design and more fab time as well. The advantage is that you can design the links to increase the leverage ratio allowing you to use a shorter shock to get more travel. If we were trying to get closer to 20" out of it then maybe a cantilever setup would have been an option but that would have also meant ditching the spare more than likely which goes against one of our main goals with the design and overall direction of this project vehicle.

Hopefully that clears it up... :)
just out of curiosity, if one of the upper mounts (driver side) were slightly inwards relative to the bottom mounts, while the passenger side was correct, would that cause the truck to not be stable at high speeds? i have this problem bc i messed up on my upper mount.
 

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not sure if you saw the thread in the suspension section, but my buddy just finished his cantilever setup good for 17" travel
 

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SEAN_at_TLT said:
A cantilever setup is quite a bit more complicated for only marginally, and debatably better results. A cantilever setup uses triangle shaped links (think: bicycle cantilever brake) that pivot and are attached to the axle housing on one end via a rod and attached to a horizontally (more or less) mounted shock on the other end. Cantilever setups place shocks at an angle they were never designed to operate at (horizontal, 90º) and with a side-load on the shocks, the seals and bushings wear out much faster than a shock oriented normally (vertical or close to it). This is not a big issue for a race truck but for a daily driver it is annoying to say the least.

The additional moving parts make for a more complicated design and more fab time as well. The advantage is that you can design the links to increase the leverage ratio allowing you to use a shorter shock to get more travel. If we were trying to get closer to 20" out of it then maybe a cantilever setup would have been an option but that would have also meant ditching the spare more than likely which goes against one of our main goals with the design and overall direction of this project vehicle.

Hopefully that clears it up... :)
Yep, that does help clear it up. So what's the best set up for a daily driver that gets offroaded hard every so often? I'd like as much travel as possible. I don't have the confidence to go welding stuff (or even let someone else) to my axle and frame, but if the benefits were really that much better over a stock bolt in application, I might be willing to be adventurous (nothing like a SAS, but pretty major for my book).
 

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Sorry to take a step backwards guys, but I've got to clear a few things up.

First of all, the shock mounts that we blueprinted cycle 13" of vertical wheel travel, not 14"+ as the title of the thread indicates. This is a good compromise for anyone who is looking for maximum wheel travel, performance and ride quality without cutting through the bed.

The 12" remote reservoir RaceRunner shocks are only stroking about 11" to get that 13" of wheel travel (there's about 1/2" of shock shaft travel left on compression/rebound). At full compression, they are angled back about 45 degrees. The valving is effectively getting softer as the suspension compresses, which is not desirable, but it's a better setup than angling the shocks in towards the center of the vehicle at the upper mounts. For even more effective dampening, you could compensate for the shock angle with position-sensitive bypass shocks.

Our shock mounts will work with any leaf-springs, but we replaced the '89 4Runner's stock 47" long leaf-springs with an 8-leaf bolt-in replacement 55" long Tacoma-pack from Deaver. Matt at Total Chaos has built similar shock mounts for Nicole's Toyota pickup and Andy's Tacoma using 62" Deaver's and Fox bypass shocks.

We relocated the front spring mounts and shckle hangers to keep the stock wheelbase and correct suspension geometry. We also removed the stock bump-stop contact pads from the framerails to allow for additional compression travel. At full compression the springs are between 1.5-2" of negative arch (about the maximum that Deaver reccomends) and at full extension, the springs are in free arch, but the individual leafs are not pulling apart. We replaced the stock U-bolt plates/lower shock mounts and rectangular U-bolts with a flip kit and then welded the stock rubber bumpstop to the new U-bolt plate on top of the spring-pack.

This particular truck clears 33x10.5" MT's on 15x8" wheels with 4.5" of backspacing. We'll have to roll the lip on the bedside to eliminate a slight rub on the outer tread blocks on FULL compression, but that's about it. In order to fit larger tires without limiting wheel travel, the inner wheelwell would need to be modified in addition to trimming the bedsides or using fiberglass bedsides.

I designed these shock mounts specifically for our '89 4Runner, so I can only say that they will work on any Toyota pickup or leaf-sprung 4Runner from '84-95.5. I'm sure the design can be applied to a Tacoma with similar results, but we haven't done it yet.

It's likely that some version of this kit will be available for sale soon (including a Tacoma-specific version), but it will not be through Trails Less Traveled. Keau just called me this morning and told me that Demello is offering a similar kit using Bilstein's 7100 short-body shocks. And I'm sorry, but we are NOT looking for any volunteers or trucks to use for prototyping. We're not a fabrication shop or a suspension manufacturer and we can't assume the liability that comes with working on other peoples vehicles.

Look for a full tech-article on this topic in an upcoming issue of Off-Road magazine. We'll include lots of information about how to cycle your suspension to determine proper shock placement and talk about how we worked with Creative Cutting Services to water-jet cut all of the parts that we designed. This is a great resource for the home-fabricator that wants to get professional-quality results.

If anyone wants to experiment with this type of setup in the meantime, we'll help out in any way that we can with measurements and pictures, etc. Like Sean said, we'd hate to see a great design only get used on one vehicle.
 

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I didn't read the whole post sorry I'm tired, but did you use 62in deavers for this set up? and it looks like a older toyota?

I have a regular tacoma length deaver set with a 2.5in shakle and the most I can get out of mine is 13.5in of bump to bump travel. the springs just want go down anymore?

I'm only useing about 12in ofa 14in shaft if that of my shock shaft and I even need to mount the lower mounts up a little because it bumps out abou .1in before the shock does and I want it to be about .5in.

I thought about pulling the clips on my spring clips but I really don't want too loose spring strength.

One last question what length shakle are you running?
 

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Jason-
We're using Deaver's bolt-in 8-Leaf Tacoma pack on an '89 4Runner with 4.5" shackles. We just moved the spring mounts and shackle hangers. The setup is only designed to cycle 13" of vertical wheel travel. I came onto this thread a few posts down to correct some misinformation (like 14"+). You're right-on about the springs max-ing out at about 13.5". We're stroking about 11" of our 12" shocks. I like that your shock mounts don't drop below the axle-housing, but our mounts had to allow for a longer collapsed eye-to-eye length (2.5" RR Racerunners) than you need with short-bodied 7100's. We could either use a shorter shock and lose wheel travel, lay the shocks over on more of and angle and lose effective damping, or build longer shock mounts.
 

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JESSE_at_TLT said:
Jason-
We're using Deaver's bolt-in 8-Leaf Tacoma pack on an '89 4Runner with 4.5" shackles. We just moved the spring mounts and shackle hangers. The setup is only designed to cycle 13" of vertical wheel travel. I came onto this thread a few posts down to correct some misinformation (like 14"+). You're right-on about the springs max-ing out at about 13.5". We're stroking about 11" of our 12" shocks. I like that your shock mounts don't drop below the axle-housing, but our mounts had to allow for a longer collapsed eye-to-eye length (2.5" RR Racerunners) than you need with short-bodied 7100's. We could either use a shorter shock and lose wheel travel, lay the shocks over on more of and angle and lose effective damping, or build longer shock mounts.
Ok that makes more sence now. I was refering to my truck, I have 14in kings and they poke thru the bed in the center. They are not mounted super high angle "rock crawler style" but 20*x20* both directions. I actully could have run them under the bed if I went with saw-aways with there shorter bodies. As it is now the shock poke thru the center about 4-5in if that and hang off the back of the axle.

It looks like you guys did a good job! those Deaver 7leafs-9leafs are pretty flexy springs for the length! I'm serious thinking about going with a modified 62in deaver spring on top of the axle! I think I could get the use of all my shocks if I did that!

Do you have anymore pics of that 4runner? I just picked up a 87 and I think I'm going to keep it fairly stock so it retains the gas milage!
 

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Do you mean 20-degrees back and 20-degrees in towards the center of the truck at the upper mounts? Wow, I'd be concerned about controlling all of the travel that you could get out of 62's. I guess you could build some type of traction bar. The 62" Deavers that Eric custom-tuned for the rear of our long-travel Tacoma will easily cycle up to 20" of wheel travel, but we're only running 2.5x16" Racerunners with right now. Why not just go spring-under? The ground clearance isn't really an issue and it would give you room for more compression.

We just finished a 3.4L conversion in that 4Runner, so the gas mileage it better than ever. We're planning on publishing the engine-swap in installments with Off-Road magazine. We also installed Total Chaos' new 2nd gen. Caddy Kit with Swayaway coil-overs and published and article about it in Four Wheeler magazine, as a counter-point to Robin Stover's straight-axle conversion (which was a really nice setup too).
 

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SEAN_at_TLT said:
http://www.trailslesstraveled.com/media/forums/toyota/89_rear.jpg[/QUOTE]

that is a very cool setup but I'd still be worried about backing into a rock and damaging that low-hanging shock/mount. Forward is not a problem with your "skid" but reverse could bite you one day ;) Was that as close to the brakes as you could get them? What about fabbing some sort of hoop-like skid with the shock mount in the middle, protected from rocks coming or going?
 

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Hey Chris-
We were more concerned about the shock geometry than anything else. We just wanted to check the positioning. For trails and rock crawling, I think Demello's higher-clearance setup is a great solution. I guess it would be pretty easy to wrap our skid-plate further around the backside though.
Thanks for the feedback.
 

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JESSE_at_TLT said:
Hey Chris-
We were more concerned about the shock geometry than anything else. We just wanted to check the positioning. For trails and rock crawling, I think Demello's higher-clearance setup is a great solution. I guess it would be pretty easy to wrap our skid-plate further around the backside though.
Thanks for the feedback.
that's what I was picturing, some sort of wrap-around with the mount in the middle of it up and away form any harm...kind of continuing what you have so far.

did you ever get the tundra axle length figured out?
 

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JESSE_at_TLT said:
Do you mean 20-degrees back and 20-degrees in towards the center of the truck at the upper mounts? Wow, I'd be concerned about controlling all of the travel that you could get out of 62's. I guess you could build some type of traction bar. The 62" Deavers that Eric custom-tuned for the rear of our long-travel Tacoma will easily cycle up to 20" of wheel travel, but we're only running 2.5x16" Racerunners with right now. Why not just go spring-under? The ground clearance isn't really an issue and it would give you room for more compression.

We just finished a 3.4L conversion in that 4Runner, so the gas mileage it better than ever. We're planning on publishing the engine-swap in installments with Off-Road magazine. We also installed Total Chaos' new 2nd gen. Caddy Kit with Swayaway coil-overs and published and article about it in Four Wheeler magazine, as a counter-point to Robin Stover's straight-axle conversion (which was a really nice setup too).
The 62in idea is still kind of a thought. I need to talk to Scott over at deaver about it? I wouldn't think the axle would be hard to control with the right valveing and shock position? But I could be wrong?

3.4 in that 4runner would be cool! I still want to see a 4.7v put in a tacoma!
 
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