How low is to low?? rockwells

Eddyj · Jan 10, 2014

I'm building my first tube chassis with rockwells. My goal was to keep it low. I built from the middle out. So now I'm building around the axles at full bump. My question is right now my axle centerline is 5 inches above belly. But I can go another 5 if I wanted to. So at full bump how much higher then the belly should I go?
I would like to know what patooyee's buggy is and maybe a little feed back from him.

patooyee · Jan 10, 2014

Re:

At full bump my axle tubes are about 7-10" above belly. A lot depends on wheelbase, tire size and intended use. I am still learning how to drive around my belly. It's super stable on steep hills and side hills but hangs me up a lot in rock gardens and sharp break overs. I find I basically have to jump the sharp break overs and power over rock gardens which I didn't used to have to do. I'm 120" long with 44" rubber. I don't recall my belly height right now but can measure tomorrow. I can say I wouldn't want to be any lower. I built the buggy at 50/50 suspension travel but have since preloaded my springs about 2" both to get up a little higher and to have more shock to absorb the jumps, something I am starting to enjoy more and learning to drive.

I also didn't build my belly plates stout enough. I am already having to redo them.

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Eddyj · Jan 10, 2014

Wheelbase is 122. Tires 42. Belly looks like between 20-22. Its just a weekend hell raiser, not going full retard, just all around rig to beat on and not have to repair every week.

Nuts · Jan 10, 2014

22" belly,68.5" highest point, shocks are about 40-60 up front and 50-50 rear, on 44s and about 118" wheelbase. Any lower and the driveshafts would go up to the axles.

Eddyj · Jan 11, 2014

Is there a Subframe under that or just a flat floor?

Nuts · Jan 11, 2014

Theres a frame, its two 1 3/4 tubes set 3/4' apart so they are about 4.25" top to bottom, and that's 2' under the "rocker" tube

Elliott · Jan 11, 2014

A lot of that has to do with how you want your driveshafts to run.and how low you want to set your motor.i set mine to where my front shaft is pretty much straight.23" of belly on 44's

The-Boss · Jan 11, 2014

I set my current build with the belly about 4 in below axle center line at full bump. The front driveshaft is angled up pretty good and the rear is straight. Belly is about 22 at bump on 54s.

Nuts · Jan 11, 2014

As long as the driveshafts don't bind it doesn't matter if they go up or down.

patooyee · Jan 11, 2014

OK, at the shop, got some measurements.

14" belly, 65" to the top of the cage. The cage could have been lower. I gave myself about 4" of space between helmet and roof inside when I built it but my seat has settled a good 4" since it was new and now I can barely see over the dash.

My belly could also be a little higher because my t-case isn't clocked. I did that because I am using the deep trans pan and with it the t-case doesn't hang any lower than the trans. I also left space underneath the seat for the passengers' asses to sink into, as that is how a suspension seat is designed. I actually have a few components that are probably bigger in dimension than some others. I use the truck oil pan as well as a truck intake which makes my engine a good 6" taller than the people using car stuff. All of this "bigness" results in loss of clearance in spots but I was going for complete drive train reliability over clearance.

The bottom of my front axle is 18", so that means the front axle sits 4" above the belly at ride height. There's 8" of up travel so that means my axle is 12" above the belly at full compression.

At ride height my front drive shaft travels up to my pinion at an angle of 12*.

And just to sum up, this is too low for my wheelbase and tire size IMO. I want to shorten my wheelbase 2 - 4 inches someday. Its kind of difficult though because my driveshaft comes so close to my thermostat housing on up travel that I had to get rid of the housing and just replace it with a flat plate. (No more t-stat.) My steering is behind my axle and it travels up in front of the crankshaft, clearing by 1/2". If I do shorten it up someday ti will probably have to be in the rear.

patooyee · Jan 11, 2014

The-Boss said:
I set my current build with the belly about 4 in below axle center line at full bump. The front driveshaft is angled up pretty good and the rear is straight. Belly is about 22 at bump on 54s.

By "current build" does that mean you have actually done something to that thing? Bringing it to AOP at the end of the month??? Or do you really mean "current planned build?"

crawlin85cj · Jan 11, 2014

Simple formula that has worked for me over and over again.

20" belly
14" front shocks set half shaft
14"-16" rear shocks set half shaft
114" wheelbase

That combo works and works really well for all around use. I like a little less wheelbase to race on with a 39" tire, around 110"

Roof height depends on how tight you cram the belly to the tcase, seats to the tcase and how much headroom you need. The tighter it's packaged the tougher it is to service. The flatter the lower links are at static ride height the better my buggies have handled and climbed vertical walls.

My $.02

The-Boss · Jan 11, 2014

patooyee said:
By "current build" does that mean you have actually done something to that thing? Bringing it to AOP at the end of the month??? Or do you really mean "current planned build?"

Little work done. Long way from hitting the trail as slow as I work. But yea I finally got back on it. She looks different than when you saw it last. Will be taking old faithful to AOP.

Eddyj · Jan 12, 2014

Looks like I'm going to set axle center line 10 inches above belly skid at full bump. I can always raise it if I don't like it that low but at least ill have the choice to go low. I'll have to do a 2 piece drive shaft, but looks like I can do 5 in above with a single shaft. So ill probably start with that and do the 2 piece later.

Elliott · Jan 12, 2014

Patoyee, am I reading it right that at full compression your belly is 6" off the ground???

patooyee · Jan 12, 2014

Re:

It's been since I built it that I measured that and I've since forgot the measurement but just from recollection that sounds about right. The thread title asks how low is too low, my answer is that is too low.

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Elliott · Jan 12, 2014

I bet that thing is almost impossible to roll

Humpy · Jan 12, 2014

115-120" wb Should b around 22-24 " belly in my opinion to be able to not get hung up but still b low enough and stable still... My current is 116. Wb and 22 belly and. 71" to top of cab... Sits good for a truggy

patooyee · Jan 12, 2014

Re: Re: Re: How low is to low?? **rockwells**

Elliott said:
I bet that thing is almost impossible to roll

I have not been able to do so yet. Been sideways on several places where I have seen others roll before. I'm actually surprised how little the belly does hang me up. I thought it would be undriveable. It's not. Some stuff just isn't worth it anymore though. Like the ugly at mm. I have to launch that so hard to clear the belly now that I'd just rather not try. Like I said, I've added an inch or two of height since building it and I want to shorten it up a tad eventually but that is all. I prefer how it is now to my last rig which was still pretty low for rockwell rigs.

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crawlin85cj · Jan 12, 2014

Humpy said:
115-120" wb Should b around 22-24 " belly in my opinion to be able to not get hung up but still b low enough and stable still... My current is 116. Wb and 22 belly and. 71" to top of cab... Sits good for a truggy

Legit formula right there