Leaf Suspension Tech - Planning for my 04' Tundra

rickashay

Explorer
Hey guys/gals,

I'm starting to consider rear suspension options for my 04' Tundra. For those that aren't aware, it's a SOA leaf spring with the inverted rear shackle design which hangs outward of the rear frame rails. This thread is primarily to gain knowledge on upgrade options based on others experience and knowledge in the matter. I am considering the arguments for my Tundra but in theory the tech is universal to all rear leaf design suspension systems so Tacoma, Pickup, old 4Runner knowledge is also welcomed. I know Expo may not be the typical source for Tech-Talk in this regard but I think some other members may also find this discussion interesting, with common uses in mind.

As some of you know, the Tundra aftermarket scene is lacking at best. Why there is no bolt-on options from OME, All-Pro, etc. I am not sure but I do hope that as the vehicle gains more popularity in the offroad community, more options will begin to appear. This leaves me to my current predicament - the rear suspension needs to be addressed but the "bolt-on" options scarcely exist, leaving me to come up with my own game plan.

My goals for the new system are as follows:
- Increased weight capacity: RTT, Bedcage, camping gear, fully armored vehicle. Guesstimate ~500lbs of extra weight in the bed with the RTT, cage, and gear.
- Increased travel: Mainly I want more droop, while gaining a slight increase in uptravel, definitely not losing any from current. (will get actual measurements today)

Current REAR Suspension:
- Wheelers 3-leaf Progressive AAL w/overload
- Bilstein 5100 shocks for 0-2" lift

Comments:Truck rides like a stock Tundra. I achieved 1-1.5" of lift with this setup although admittedly I do not have measurements to prove. Eyeballing this one. Height is OK and ride is good. Weight capacity is OK and travel is pretty terrible. Currently at bump, my 35's are kissing the upper fender edge, meaning any more uptravel and trimming will be required into the bedside, although I will confirm today if a fender roll may allow the tire to sneak inside the fender more.



Option 1 - Deaver makes a G57 bolt-on leaf pack, ~$650. It is one of the only full leaf packs available as a "production model Tundra leaf pack". It is a 10 or 8 pack unit (I'd have to confirm) and claims to offer 1.5" of rear lift over stock and increased travel. I am assuming the travel numbers come from an increased amount of arch in the pack, although I can't seem to find how many more inches of arch it has over stock, "+X". The small amount of information I have found says the pack works great but is not very good for any type of load carrying capacity, seeing as how it was designed with the baja scene in mind. I would probably keep the stock hangers in place with this setup but need to do some shock relocation to increase travel further.

Option 2 - Custom pack. Alcan and Deaver will both build custom packs, ~$800+. They can tune them to your liking and build any amount of extra arch into the pack. Weight capacity would be where I design it to be which is a huge plus, but I'm just not sure how much increasing arch numbers contributes to overall travel? Uptravel vs. droop? Custom shock mounting would probably make this setup more optimal.

Option 3 - The good old Chevy 63's. A common swap for older yotas. Chevy 1/2 ton 63" leafs, ~$150. These leafs are known to ride ultra smooth and provide a lot of additional flex. The leafs come in two versions 2WD - 3-leaf + overload or 4WD 4 leaf + overload. Junk yard leafs and from my research typically will lift 2-3" with the swap alone. I've heard mixed comments regarding weight capacity but they were a true 1/2 ton leaf so they should do ok. Bonus on the cost side but the downfall is you need to fabricate a new front spring hanger forward of OE mount and rear shackle has to be flipped. Ruffstuff makes custom shackle flips here: http://www.ruffstuffspecialties.com/catalog/UNFLIP.html and also Chevy 63" full DIY kits here: http://www.ruffstuffspecialties.com/catalog/R1799.html. I figure by the time it's all fabbed on and bolted up, I would be into this swap including leafs for around $800 including reworking of the shock mounts for more travel. I would have the ability to change shackle length to slightly alter the produced lift height to my desire.

Option 4 - Deaver SUA setup, ~$1500+. This would relocate the spring back under the axle housing. Rear hangers would need to be custom built. Bedcage for extended length shocks would also need to be custom built. Mucho travel gains, in both uptravel and droop. Pretty much the ultimate but I expect once you throw fabwork, custom shocks, and leafs into the mix this is a $3000+ option and full LT. Also losing bedspace to accommodate the cage. Pretty much, not even considering this, but wanted to state it as an option.

Let's hear some feedback, experience, and opinions below. I will update this post for my specific case as I get some measurements for my factory setup today as I plan to pull the rear shocks and full cycle and measure the suspension. Regarding travel I don't really have room (tire clearance wise) to improve uptravel so my gains are going to be in droop. I would like to have a balance of uptravel and droop but I would rather keep the cutting wheel away from the bedsides if possible. More droop is typically the ideal setup for crawling where more uptravel is desired for high speed stuff. I definitely do more slow trails than anything. BUT doing lots of overland style travel means it needs to be "happy" on those rough gravel roads. I think keeping current uptravel constant with more droop may be ideal.. but thats why this thread is here....
 

rickashay

Explorer
Current Suspension Measurements - measurements taken from top of axle housing to bump stop strike plate.

Ride height: 9 3/4"
With shocks in place at full droop: 12 5/8"

IMG_0168.jpg by RickaShay24, on Flickr

With shocks removed at full droop: 14 1/4"

Full compression (bumpstop just touching strike plate, no bumpstop compression): 5 3/4"

IMG_0164-2.jpg by RickaShay24, on Flickr

Tires just before bump - you can actually see where the tires are cleaning the paint off on the edge of the fender when it's full compressed.

IMG_0166.jpg by RickaShay24, on Flickr

Doesn't get much tighter than this:

IMG_0157.jpg by RickaShay24, on Flickr

This means I cycle a mere 8.5" of rear travel - This number is pretty conservative as I was ultimately measuring from just behind the drums. The wheel will leverage more travel realistically but I doubt my wheel sees more than 10" or rear travel.
This 8.5" would be broken down with approx. 4" of uptravel and 4.5 of droop. I'm good with the 4" of up, but definitely disappointed with the droop. In retrospect though, the shocks are limiting droop by 1 5/8" which would probably equate to 2-2.5" at the wheel.
 
Last edited:

toyotech

Expedition Leader
Good info. I currently have a block in the rear of mine from pervious owner. I need to see what size it is. I want to get rid of it but want the lift it have from the replacement. Wheelers 3 leaf looks like a good option for me. Could you measure from bottom of your fender to center of axle? So I can compare it to mine even tho I have a topper on. I'm gonna remove it for paint when weather permits. Thanks. Keep an eye on this thread.

Wonder why we can use tacoma leafs or the lengths different?? If so. We can use any tacoma leaf lift kit and remove the main leaf for ours so it still bolts up??


Sent from my iPad using Tapatalk
 

rickashay

Explorer
Good info. I currently have a block in the rear of mine from pervious owner. I need to see what size it is. I want to get rid of it but want the lift it have from the replacement. Wheelers 3 leaf looks like a good option for me. Could you measure from bottom of your fender to center of axle? So I can compare it to mine even tho I have a topper on. I'm gonna remove it for paint when weather permits. Thanks. Keep an eye on this thread.

Wonder why we can use tacoma leafs or the lengths different?? If so. We can use any tacoma leaf lift kit and remove the main leaf for ours so it still bolts up??


Sent from my iPad using Tapatalk

I'll get the axle to fender measurement for you next time I'm in the garage, not a problem. My Wheelers pack rides excellent and does just fine with weight. It is definitely a good option for those that just want some lift while keeping everything else constant. I'm chasing a little more flex so thats where things get interesting I guess. My 3 leaf pack will be out soon if you want to work something out in the next couple months.

Interesting thought on the Tacoma stuff. 1st gen Tacos have a regular shackle design, and I'm pretty sure our leafs are longer. Building a hybrid pack could definitely be an option but I wouldn't want to buy a All Pro Expo or OME pack just to rip it apart and find out it wont work. I'm kind of leaning towards the Chevy's but I need to do more research. I know Dyogim is running them on his SAS'd Tundra and really likes them. He's sitting pretty high but he's also running a longer shackle, Chevy "lift" springs, and a block and he said he's at around 5-6" of lift. I think with a regular 63" pack and a shorter shackle I would net 2-3" lift.
 

mtnkid85

Adventurer
Stock leafs are 2-1/4" wide. Chevies are 2-1/2" wide. I forgot to measure length of stock leafs.

I thought they might be 2.25", same as the Tacoma widths.

I've used the chevys on an older 4runner and really liked the ride/flex they provided, but I was wondering about using Tundra springs for my current Tacoma.
One thing about the 63" chevys is they are LONG. I suppose on Tundra they would fit in a little better, but the packaging on smaller vehicles is a little ridiculous.
 

Blender

Adventurer
I'll throw in some cloudy info to tide you guys over until I can duplicate rickashay's measurement scheme.
-G57 10 leaf spring pack is 2.5" thick iirc. Not compatible with stock overload spring.
-current hub to fender measurements: 22.75" with short shocks installed.
-shock length required at factory mounting locations: 15.5-25.75" assuming stock stud/Heim mounting style. Compressed length should probably be a little shorter to allows stock bumps to deform.
 

Climbermac

Observer
rickashay, you are in almost the same place I am. I am running the exact same rear end save that I have a pair of Firestone airbags (to add carrying capacity) with Daystar cradles (to not limit travel). I'm not sure how old your 3 leaf pack is but mine are pretty shot. I have to run 30 or 40psi in the bags to keep the ride height balanced with the front. Without the bags I can barely tell the AAL pack is there. As you noticed the shocks are also limiting the droop. My rear dropped another 3"+ when I disconnected the shocks on the lift last time I had it up to work on it. I know Toyota somewhat uses the shocks as a "limit strap" but we can just install an actual strap and run shocks with enough stroke to use the full flex of the suspension. I am aiming for just that: Alcan springs built to settle to my desired lift (I'm still working on that number) longer shocks to allow full cycle and a limit strap to keep the driveline together. I also talked to a crawler friend of mine about keeping my airbags to act as overload and a kind of air bumpstop. I can't seem to track down a good rear shock yet, I will want to get the new springs on and settled so I can be sure of the max travel before I source the final shock setup.
 

rickashay

Explorer
Sub'd. Looking for rear springs myself

Glad to finally see some bites and hopefully you find some useful tech in here!

I thought they might be 2.25", same as the Tacoma widths.

I've used the chevys on an older 4runner and really liked the ride/flex they provided, but I was wondering about using Tundra springs for my current Tacoma.
One thing about the 63" chevys is they are LONG. I suppose on Tundra they would fit in a little better, but the packaging on smaller vehicles is a little ridiculous.

Yah they are pretty popular with the older crowd but undoubtedly long. The front hanger typically hangs off the frame (unless you french the hanger into the frame) but really I don't think that is that big of a deal. I mean my 4Runner and LC both had the rear lower control arm mounts that hung down excessively. The leaf mounts are substantially more low profile than those... valid points though. I need to see how long my factory Tundra leaf pack is. For some reason I remember reading they were ~60".

I'll throw in some cloudy info to tide you guys over until I can duplicate rickashay's measurement scheme.
-G57 10 leaf spring pack is 2.5" thick iirc. Not compatible with stock overload spring.
-current hub to fender measurements: 22.75" with short shocks installed.
-shock length required at factory mounting locations: 15.5-25.75" assuming stock stud/Heim mounting style. Compressed length should probably be a little shorter to allows stock bumps to deform.

Good info and I look forward to your measurements for comparison. No matter what route I go, I plan on re-doing the upper and lower shock mounts to fit a longer stroke shock in place. Then I can order eye-eye shocks and not the stupid stud design.... Hoping to cram a 12" stroke shock under the bed, but willing to lower the factory axle side mounts a little if needed. But then again, I need a leaf spring that will droop enough to allow that 12" shock to stretch.

rickashay, you are in almost the same place I am. I am running the exact same rear end save that I have a pair of Firestone airbags (to add carrying capacity) with Daystar cradles (to not limit travel). I'm not sure how old your 3 leaf pack is but mine are pretty shot. I have to run 30 or 40psi in the bags to keep the ride height balanced with the front. Without the bags I can barely tell the AAL pack is there. As you noticed the shocks are also limiting the droop. My rear dropped another 3"+ when I disconnected the shocks on the lift last time I had it up to work on it. I know Toyota somewhat uses the shocks as a "limit strap" but we can just install an actual strap and run shocks with enough stroke to use the full flex of the suspension. I am aiming for just that: Alcan springs built to settle to my desired lift (I'm still working on that number) longer shocks to allow full cycle and a limit strap to keep the driveline together. I also talked to a crawler friend of mine about keeping my airbags to act as overload and a kind of air bumpstop. I can't seem to track down a good rear shock yet, I will want to get the new springs on and settled so I can be sure of the max travel before I source the final shock setup.

Yah its a bummer that we don't really have any options for flex AND weight. I'd opt for a bolt in pack and do some shock relocation if I know I could get 12" + of travel with the factory leaf setup. However I just don't see this being possible. If I'm going to go custom, I might as well make it worth it and get the most travel I can. Alcan springs do look interesting for sure. I look forward ot hearing which direction you pursue.
 

photoman

Explorer
Find a good spring shop. Find out who works on city/state vehicles, buses, etc.

In Phoenix I took my truck to http://dunbarspring.com/ after installing my Icon Suspension. Re-arch and add a leaf to accommodate for RTT, eventual bumper build and full loaded weight- installed for <$600 out the door. On highway is better than stock and works great with the Icons off road.
 

rickashay

Explorer
Find a good spring shop. Find out who works on city/state vehicles, buses, etc.

In Phoenix I took my truck to http://dunbarspring.com/ after installing my Icon Suspension. Re-arch and add a leaf to accommodate for RTT, eventual bumper build and full loaded weight- installed for <$600 out the door. On highway is better than stock and works great with the Icons off road.

Good idea for sure. However I really would like to get into the tech of why one leaf setup will work better for flex over another. Building a custom pack to suite my weight needs isn't my issue. It's getting my weight needs while increasing flex, and how that is to be accomplished.

An example, DMZ rear shock relocation for 2nd Gen Tacos, which also use the factory inverted shackle design. Attached is a photo showing the inverted shackle and this setup at full droop. Ignore the whole spring under part as it is void in this argument.

DSC_0872.jpg


I did not photograph my Tundra at full droop but should have. The shackle angle isn't anywhere even close to this at droop, and the shocks were disconnected, so I know that wasn't my limiting factor. I don't understand how the 2nd Gen inverted shackles will rotate this much? Maybe my Tundra shackles are binding?
 

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