Since my last Moab trip in April when I wanted to test out the new tires and especially the drivetrain I have been tweaking the suspension just a bit as I had a very slight interference issue in the rear and a more major interference issue in the front.
If you remember from a previous post, the front was contacting the front bumper upon full stuff and turned full lock in either direction. I cut the front bumper a few weeks back to gain some clearance and then played with my bumpstops on the front to get me as much compression as I could without contacting anything. I think I'm there. I ended up trimming the front bumpstops down 1/2" to a total of 3" tall bumpstops in the front after trimming the front bumper as I had plenty of clearance.
In the rear I also had a little more clearance upon full stuff so I opted to remove about 1/2" of bump stop from the rear as well to get those 37's up a little closer to the fender as well as the rear bumper. The areas at the front of the rear wheelwells where I heated and recontoured the inner fender are providing ample clearance now.
From my experience for running dunes/desert or high speeds the 50/50 droop/uptravel ratio is a good target. For trails and rocks I like to shoot for closer to 60/40 droop/uptravel but have a few guys that prefer to be closer to 70/30 droop/uptravel. Although a slightly lower COG seems to be what everyone seeks these day, many times a low COG just isn't practical and still be able to clear obstacles without dragging over them. So unfortunately a low COG does negatively affect breakover angle so it becomes a balancing act of less belly clearance vs. the tippy-ness of more lift, so I try to get around that 60/40 droop/uptravel ratio measured from ride-height and then balance that low COG and lift height. I should also mention that my Jeep is not strictly a rock-crawler but a do-all Jeep so I want it to have great pavement manners from winding two-lane country roads to interstates to mountain passes yet still flex decent and wheel great off-road. Obviously if I were building a more specific car for rock-crawling or high speed desert racing those ratios would be different and I would want a lot more overall travel and possibly even go with coilovers to get that increased travel. Also worth noting that I wanted a "sleeper" if you will, meaning something that when the average person looks at my Jeep they simply say "oh that's like every other 4-door Jeep on 37's", yet to the experienced eye one will spend hours looking at all of the small details and the fact that I didn't sway from the OEM lines.
This is why I have kept the OEM fenders and didn't hack and cut up my body. I'm not a huge fan of flat fenders nor cutting and hacking up the wheelwells for a daily driver as I want this to look just as nice in 10-15 years as it does now. I also didn't want to add wheel adapters and space them out an additional 1.5", but it did cost me a little bit of travel by keeping my wheel backspacing at 4.5". Again, if I were building a more focused or specific car for desert racing or rock crawling I obviously would have done things differently.
I increased my suspension travel slightly from OEM specs of 8 inches of travel. I have slightly longer Fox 2.0 shocks installed but I also went one step further and installed limiting straps several years ago as I don't like the shocks to be either my bump stops OR my limiting straps as that is hard on shocks. I had also ripped off the upper control arm brackets from my rear axle a few years ago due to having so much flex so I opted to install some limiting straps and eliminate some of those stresses at the cost of overall travel.
I currently think I have it dialed in perfectly but won't know for certain until I am able to get it off road next month. In the front I have 10 inches of total travel, 5.75" of droop and 4.25" uptravel which nets me a 58/42 droop/uptravel ratio. I can now turn my front tires to full lock at full stuff and clear my front bumper by about 1/2" at the tightest point. In the rear I have 9" of total travel with 5..5" of droop and 3.5" of uptravel netting me a 61/39 droop/uptravel ratio.
I don't have any pictures of the front end stuffed when I tested it a few weeks ago but here are a few pictures of my rear at droop and full stuff including the tightest point. I took these this morning on the way to work and after I took 1/2" of rear bumpstop out as I had some clearance left. I think this is about perfect where I want to be.
Drooped out nearly to the max. as my limiting strap was not completely stretched yet.
Full stuff up against the jounce stop. I think a hard stuff could maybe get it another 1/4” but that’s about it and I have clearance for that.
The tightest point at full stuff and again, I “think” I have built in a little cushion for another 1/4” if needs be such as a hard stuff.
Mike
