Well, I've put this off for quite some time but I'm finally getting around to starting a thread for my buggy. First, the introduction.
One of the reasons I'm starting this thread is I'm getting ready to redo the suspension. Throughout my research I actually stumbled across the original build thread for my rig on RME! @CSR originally built this buggy and he did an awesome job! I bought this rig from him back in the spring of 2017. For those of you who have seen my buggy, it has a pretty unique suspension design and I'm a big fan of the concept, you can check out the original build thread here: https://www.rme4x4.com/threads/buggy-build-suspension-experiment.110938/.
So I grew up rock crawling with family and friends and always wanted to build a buggy. Post college I moved out to Utah, started working, and starting saving to build a rock crawler. I came across what's now my buggy on KSL; it had 90% of everything I wanted at the time and the price was reasonable, couple that with the fact that the apartment and small garage I was renting in an overly sensitive HOA at the time didn't lend itself to building a buggy I pulled the trigger. I've wheeled this up until now with fairly minimal changes, so far I've:
And another picture... (this one you can see a lot of what I'll be talking about below)
Aaaand one more.
Recently I purchased a house, and along with that house, an actual shop and no HOA! Finally getting everything settled in and as Spring is quickly approaching I want to change things up a bit on my buggy suspension wise. So throughout the original thread this things been referred to as an experiment, which it definitely is in terms of suspension. So here are my impressions of the results from this experiment. A few details related to stance and suspension geometry:
So everything above is just how I understand the various topics/theories; I've learned a ton from this forum and other forums like it and I'm definitely looking for different thoughts and opinions so if you guys have ideas I'm all ears.
One of the reasons I'm starting this thread is I'm getting ready to redo the suspension. Throughout my research I actually stumbled across the original build thread for my rig on RME! @CSR originally built this buggy and he did an awesome job! I bought this rig from him back in the spring of 2017. For those of you who have seen my buggy, it has a pretty unique suspension design and I'm a big fan of the concept, you can check out the original build thread here: https://www.rme4x4.com/threads/buggy-build-suspension-experiment.110938/.
So I grew up rock crawling with family and friends and always wanted to build a buggy. Post college I moved out to Utah, started working, and starting saving to build a rock crawler. I came across what's now my buggy on KSL; it had 90% of everything I wanted at the time and the price was reasonable, couple that with the fact that the apartment and small garage I was renting in an overly sensitive HOA at the time didn't lend itself to building a buggy I pulled the trigger. I've wheeled this up until now with fairly minimal changes, so far I've:
- Sold the 40" Pro Comp Xtreme MT's and replaced with 45" TSL SXIIs
- On about the third trip out playing around BFE I tore the sidewall of one of the 40" tires, figured it would likely happen again after reading several reviews so I got rid of them. Also, I love how low the rig sits but it was realllly low with 40's, stepping up to 45's (actually around 44") made a huge difference crawling and the drive train up until now has handled them just fine.
- Replaced the 14 bolt wheel seals
- Replaced the stock Ford Dana 60 manual locking hubs with TMR drive flanges
- Rebuilt the front skid plate as it interfered with the leading arms during articulation
- Rerouted the hydraulic steering lines
- Added wheel spacer to the back end because during full articulation the tire would rub the coil over, this also matched the front and rear track width
- Replaced the seat belts with Crow Enterprise 3" four point harnesses
- I actually 3D printed some nylon coil over reservoir mounts which turned out really cool and have been working well (I should post something on this later)
- Due to the drivers side exhaust manifold location I was burning plugs in two pretty bad so I rerouted/shielded them
- Built a hydraulic steering cooler shield as it was in line with the tire roost and at risk of me kicking it in when I got in and out
- Removed all the polycarbonate windshields as they got scratched and dirty and difficult to see through
- Built a couple ammo can tool box mounts
- Replaced the starter
- Maybe a couple other little things...
And another picture... (this one you can see a lot of what I'll be talking about below)
Aaaand one more.
Recently I purchased a house, and along with that house, an actual shop and no HOA! Finally getting everything settled in and as Spring is quickly approaching I want to change things up a bit on my buggy suspension wise. So throughout the original thread this things been referred to as an experiment, which it definitely is in terms of suspension. So here are my impressions of the results from this experiment. A few details related to stance and suspension geometry:
- Wheelbase = 120"
- Track width, outside of tire to outside of tire = 98"
- Belly height = 17.5" (only ~15.5" before I swapped tires!)
- Rear 18" 2.125 ADS coil overs mounted directly to the axle, only ~4" of down travel, duel rate coils at 100#/400#
- Front 10" 2.5 ADS coil overs mounted to the leading arms ~50/50, only ~2" of down travel and only using about 8" of total travel due to limit strap, single rate coils at 400#
- It's pretty fast and rides fairly well through the rough stuff, but not as well as I think it could
- I think this has a lot to do with three things
- The valving in the front end
- The rebound is stiff and the compression is very light (you can read the thought process behind this in the original build thread). If you go too fast or hit something too hard, the shock will blow through the stroke and bottom out
- The lack of droop
- As mentioned above, I have very little down travel. Down travel is limited by the driveshafts (both front and rear) contacting the frame as well as the current coil over mounting positions
- If you go too fast through the whoops the tires can't maintain contact with the ground and it gets pretty jackhammer-ish real quick as the axle flies through the compression stroke with the light valving loading up the coil and then smacks the limit strap on the rebound
- As mentioned above, I have very little down travel. Down travel is limited by the driveshafts (both front and rear) contacting the frame as well as the current coil over mounting positions
- The rear coil combo
- From what I've learned, the 100#/400# combo is a very large spread. What I've witnessed is that often times the top coil is fully collapse (bind) and I'm riding a lot on the 400#. For comparison, the rig is weighted very evenly front to rear nearly 50/50; and I have 400# coils on the leading arm setup in the front (lots of leverage) and essentially 400# springs mounted directly to the axle in the rear (no leverage) which I think is contributing to the harshness in the back end.
- The valving in the front end
- I think this has a lot to do with three things
- Rear steer
- Not the good kind that I wish I had with such a long rig ha... So due to the tall height my axle side upper link mounting point, and the fact that both the upper and lower links are relatively flat, the roll axis of the axle (from the upper links LCP to the lower links LCP) is relatively very steep leaning forward. When the rear end articulates, you can feel the back end walk side to side. Given the geometry, i'm sure the same thing happens in the front but you just don't notice it with the steering axle.
- Down travel and belly height
- Sharp break overs destroy me. I'm not even close to being able to go up the rock pile at Moab and the son of rock pile even gives me fits (it drives me crazy). This buggy is great at steep stuff but if it has a sharp break over at the top I'm screwed. As a few RME'rs can attest after stacking rocks for 15min after I got stuck on our trip to Coyote Canyon, boulder fields aren't my cup of tea either.
- Bump stops
- The ADS coil overs have a ~1" rubber bump stop on the bottom but that's it. The addition of bump stops not only would help the ride but also would save my coil overs.
- Single Link
- The top links are really a wishbone setup, two heims at the chassis and one at the axle side. Due to the large link spacing I have at the axles the single upper heim has a lot of leverage to reduce its load, but just having a single failure point worries me. If that single heim was to break there's nothing to stop the axle from wrapping up and causing who knows what damage.
- Raise the belly height
- This buggy is very fun to drive with the CG being below the vehicle roll axis; at speed it tucks into the corners (opposite of body roll) and in off camber situations it actually leans up hill. Raising the belly height puts me at risk of losing these characteristics so I'm trying to balance the increased belly height and stability. On the other hand, I think it will help to raise the belly height for cornering because currently this thing loves to drift, raising the belly height will transfer more weight to the outside of the outside tire providing additional traction.
- My plan is to raise the belly from 17.5" to 20". Increasing my tire size ~4" provided about 2" of lift which made a hug difference, so I'd expect this ~2.5" to significantly help as well.
- Raising the belly height should also give some slope to the lower links raising the lower link LCP and reducing the amount of rear steer
- Get some droop
- The current limitation to droop is my drive shafts hitting the frame. I plan to run two piece drive shafts front and rear, remount the coil overs and target about 50/50 stroke up/down (still kicking ratios around). Again, this extra droop may lead to the CG going over the roll axis for an instant throughout the travel... but it's an experiment after all so we'll see.
- Coil overs
- Front
- Remount
- Revalve the coil overs to a more traditional valving style
- Go to a duel rate coil over setup
- Rear
- Remount
- Respring the duel rate rear for a more subtle transition/shared load
- Front
- Add bump stops
- Change over from the wishbone top link setup to two separate top links
So everything above is just how I understand the various topics/theories; I've learned a ton from this forum and other forums like it and I'm definitely looking for different thoughts and opinions so if you guys have ideas I'm all ears.
