Sway in Hi-Top Van Conversions

[yamsack]

Hey all,<br>I was reading one of the threads here and <b>4x4tour</b> mentioned how his hi-top van tended to have swaying problems while driving.&nbsp; Is this generally a problem for all hi-top vans?&nbsp; Additionally, what other problems are there in hi-top vans?<br><br>Up to this point, I was settled on getting a hi-top van conversion to prevent having to stoop in the van.&nbsp; However, perhaps there may be more problems than it's worth in having a hi-top van.&nbsp; Thanks all.<br><br>

 

[user 423]

&nbsp;&nbsp;&nbsp;&nbsp; Well, there's a lot of variation out there.&nbsp; The extended hi-top (2' rise) I drove a few years ago was pretty heavy and with new KYB shocks it seemed OK most of the time unless the wind was really blowing. Actually, a regular extended van may get blown around a bit in heavy crossswinds, let alone a hi-top. Then a hi-top on a regular length van would be in between, I guess. Some of the newer vans have longer wheel bases and that probably helps with stability. Driving slower would help also if it got hairy...lol.<br><br>&nbsp;&nbsp;&nbsp; You'd want to keep the weight down low....tools, batteries,fluids,etc. A tight frontend is important also. Some of the tops are a little more aerodynamic than others, so that could make some difference. I also have seen some older vans that had dropped floors (on one side) that you could stand in with just a low-level top. <br>

 

[stude53]

<FONT size=3 face="arial, helvetica, sans-serif">I found this on a Ford Truck Site and thought it might be helpful here.</FONT><BR><FONT size=3 face="arial, helvetica, sans-serif"></FONT>&nbsp;<BR><FONT size=3 face="arial, helvetica, sans-serif"></FONT>&nbsp;<BR><P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Verdana','sans-serif'; COLOR: black; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'"><FONT face="arial, helvetica, sans-serif"><FONT size=3>HIGHTOP WIND SWAY</FONT></FONT></SPAN></P><P style="MARGIN: 0in 0in 10pt" class=MsoNormal><SPAN style="LINE-HEIGHT: 115%; FONT-FAMILY: 'Verdana','sans-serif'; COLOR: black; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'"><FONT size=3 face="arial, helvetica, sans-serif">Just had a brain storm and figured out the problem. Add E rated tires to rear axle only. Rear axle is rated at 3800 on my E-150 and my last weigh at truck scale showed almost 3800 which is almost the max rating of my tires and would be over that if fully loaded for more than a weekend trip. However my front axle was only 3000 lb. and well within the tires 3968 lb. max rating.<BR><BR>Since the front HD shocks cause a very harsh ride but the HD rear don't, you want to keep the lower rated tires in front because they can easily handle the 3000lb. weight. Now this is how I can prove what I'm telling you. If you remove your shocks from front and leave HD shocks on rear axle and go for a drive the van still drives straight down the road with no body roll because the rear shocks control that. If you put HD shocks on front your van will ride like a semi truck over every little crack in the road. That is why I switched to a med. shock up front. This will only get worse if front tires are stiff E rated with the lower weights not flexing heavier side walls. As the over loaded or almost over loaded rear tires sway back and forth the alignment between front and rear tires change causing you to counter steer based on the seat of the pants feel and drift, then after you counter steer the flex changes and loads tires the other direction so you counter steer again and the never ending cycle continues. Like driving a tractor down the road with big rear tires swaying back and forth like balloon tires. Ever watch the guy driving bouncing and trying to keep it straight the faster he drives. Add high winds causing additional loads because of the leveraged forces applied and this problem gets worse. A rear axle already loaded to the max rating with tires at the max rating then you add additional side load forces from wind or dips / bumps and something has to flex. My suspension and HD shocks are not the prob. which only leaves the tires. The E-250 had E rated tires all the way around which caused the harsh ride up front that the E-150 didnt have. Now for the good part, if your only putting E rated tires on the rear your not adding additional rotating weight to the front and since most of your braking is done with the front brakes your not reducing stopping power on the front. Your only adding rotating weight to the rear where you need it to support the heavier loads. This will still reduce MPG but only 1/2 as much and you can justify that small loss. <BR><BR>This is why empty semi trk. with box trl. doesnt sway / drift all over the road in high winds as bad as my little van does, because the tires are designed to handle much more weight. The avg. semi trk. DOT max is 80k lb. with tires max rated almost double that. max steering is 70% of rating and rear drives are about 50% of tires max. No wonder they dont sway going down the road like a van. My E-150 van tires are at the max so if I installed tires on rear which offer considerably more than I carry, this should solve the sidewall flex sway issues. The E rated would put me at 71% of the tires max and front at 76%. A semi front axle is rated at approx. 70% of the tires max so the front must not effect sway like the rear for the rear to be over rated by 20% more then DOT allows a std. semi. These are approx. # and will vary but you get the idea. <BR><BR>Bottom line: Ford is rating our E-150 van to use tires which would operate around the max or over after conversion and loading a few people inside. The conversion co. not only did not change this but put a sticker on door telling people to run 35 psi. when ford said 41 psi. No wonder the E-150 gets a bad rap for swaying and hard to drive in windy conditions. You would think after all the vans which have had this problem a conversion co. would figure it out. A simple little fix of E rated tires on rear of E-150 would have changed the way many people looked at vans because most conversions were done on 150 and not 250 so most drove them and realized they sway / drift that was the end of wanting a van. Except for us hard core van people : ) The 2004 E-150 came with standard rated tires 25/70R/16 rated at 1984 lb. ea. but the new 2010 E-150 comes with LT225/75R/16/E rated at 2680 ea. The brakes on 2004 150 were 11.72 dia. and the 2010 E150 has 13.58 to stop those heavier tires along with extra GVWR. Now get this the 2004 E350 was only rated at 300 lb. more on front suspension then 150 but around 1600 more on rear with brakes smaller then the new E-150. And yet they put the same 3042 lb. rated tires on the front 3900 lb. rated suspension. Have to keep the same tires all the way around. Still think the manufacturer knows best ? They put tires on front rated at 2184 lb. more then the suspension is rated at which adds rotating weight to the front brakes doing most of the stopping. Have to keep them all the same. Then you have a conversion co. telling people to run 35 psi in a 7000 lb. vehicle with basically car tires. I cant count the number of times I have heard people say stick to what the manufacturer specs are because that is what they pay all those engineers for and they know much more than you do. They prob. do but the follow thru seems to be the issue based on the specs. If it is cheaper to make disc brakes all in the same size for every van then go ahead but if not you dont put the same size disc on rear which adds weight you dont need. Why use a front axle rated at 5000 lb. then put suspension rated at 3900 lb. if you can reduce more weight using smaller front axle to match the suspension. On the 2007 E-150 they increased the axle rating by 1000 to 1200 lb. and went up to the E rated tires but kept the same 30mm shocks and smaller 11.72 dia. disc brakes. What was the one reason I didnt want to add E rated tires ? because of loosing stopping power from increased rotating weight. Who is designing these vans any way... I'm basing this on the ford specs sheet, maybe somebody made a mistake or maybe they had to get rid of some old parts. What other reason would there be for installing a axle GWR so much higher than suspension is rated at but back in 2004-2005 you rated suspension and axles almost the same.&nbsp;<BR><BR>Funny how the brain works... Once I sat down and wrote all this out ( it was 10 X longer than this but I deleted most after the obvious hit me. ) it was like a light bulb came on, why didnt I figure this out before ? Because vehicles come with the same tires in most cases and using the same 4 tires has been drilled into our heads. You must X rotate, etc. etc. well, not any more. I cant believe this has been right in front of me the whole time. <BR><BR>I only needed E rated on rear to solve all my problems without loosing my E-150 ride. I will have new E rated tires on rear soon and let you know. The size is almost the same and I have 30 days to return them for a full refund so what do I have to loose besides time at Sam's waiting. I'm confident this is the solution and still kicking my butt it took so long to figure out. Just in time too, I do most of my traveling this time of year.<BR></FONT><BR style="mso-special-character: line-break"><BR style="mso-special-character: line-break"></SPAN></P><BR>

 

[4x4tour]

I had the same airbags on my 94 G20, and it helped swaying a tiny bit on turns, but driving on a highway with medium windy conditions was BRUTAL.&nbsp; It was a PIA.&nbsp; Sweaty palms from puckering was a given... I think Fords are more stable, in general. <br><br>I had brand new D-rated tires on it, but maybe some narly E-rated ones (less flexible side-walls) would have worked a little better, but the best fix is to put Hellwig anti-sway bars front and rear, along with Bilsteins <br><br>I have Rancho RS9000's on my 4x4 van only because all of the center of gravity is in the drivetrain, and they are cheaper than bilsteins.&nbsp; I don't get ANY swaying&nbsp; I came home camping yesterday, driving the same windy highway and this van doesn't budge.&nbsp; It drives like a Cadillac. With the other, I felt like I was going to be blown over all the time.&nbsp; Passing a big rig on the hwy was always an experience. <br><br>So, for a 2-wheel drive van, you can go to a junkie and get some sway bars, but they will be thinner (still better than nothing),&nbsp; E-rated tires, along with GOOD heavy dampening shocks.&nbsp; If your rear sags, airbags will perk it up.&nbsp; <br><br>Here's a pic to show the g20.&nbsp; It was in MINT condition.&nbsp; I hated selling it, but....lol <br><br>

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