Sprinter-Forum    
 

Go Back   Sprinter-Forum > Sprinter-Based RV's & Conversions > Sprinter-Based RV Brands > Leisure Travel Vans > Unity


Reply
 
Thread Tools Display Modes
Old 10-15-2016, 12:34 AM   #1
kmay
2013 Unity MB
 
Join Date: Sep 2016
Location: Mississippi
Posts: 192
Thanks: 50
Thanked 105 Times in 62 Posts
Default Suspension upgrades to improve handling in gusty winds

Hello all,

I have been following the sway bar and air suspension discussions with interest. I started this Sprinter journey from a variety of info sources, one of which was the Advance RV web site. So "they" say air suspension is an important upgrade to improve handling in high crosswinds as well as eliminating the wandering from big rig bow waves and the turbulent air in their wake. I don't know if it is true or false, whether there are other alternatives and which would give one the most return on investment. I am not even sure suspension can resolve aerodynamics of a box.

First two days of our maiden voyage were beset with high winds and it took much of the joy away. In light wind, I was very happy with the suspension. I can modify driving enough to limit time in turbulence from the big rigs. I don't mind the rocking over big transitions, it seems constrained as well as a gentle reminder, this ain't a SL coupe. So I wonder if I need top shelf upgrades. Maybe just a little something to take the edge off the worst stuff.

Would someone drop a link to RV laden sprinter suspension 101? I have some car and light truck suspension experience but am unsure if any of that would apply here as we were always looking for less roll and consistent tire contact.

What would be the best suspension upgrades to improve performance in the aforementioned crosswind/turbulence?

What would help but not cost as much? I am asking for a value kit to compare against the best. Maybe a rear stabilizer kit, larger bounce stops and a front steering dampner?

Thanks,
kmay is offline   Reply With Quote
The Following 3 Users Say Thank You to kmay For This Useful Post:
chadww (06-03-2017), Smitty550 (04-29-2018), suekurtz (06-21-2018)
Old 10-15-2016, 01:31 AM   #2
NevadaBlue
 
NevadaBlue's Avatar
 
Join Date: Sep 2016
Location: Nevada, USA
Posts: 235
Thanks: 247
Thanked 53 Times in 46 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

This will be interesting. My van will be 4x4 and the build list says it comes with some 'heavy duty' suspension parts. The machine is already a 2500 and I have found from experience that too heavy of a suspension can be worse than too light. I worked in mining all my career and we found that in general transportation use, heavy suspension beat the pickup trucks to death quicker.
Watching from here with interest.
NevadaBlue is offline   Reply With Quote
The Following 3 Users Say Thank You to NevadaBlue For This Useful Post:
Digor6 (01-18-2017), Old Crows (11-29-2016), suekurtz (06-21-2018)
Old 10-15-2016, 02:18 AM   #3
calbiker
 
Join Date: Aug 2008
Location: Santa Barbara
Posts: 1,809
Thanks: 249
Thanked 804 Times in 536 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

In order of best bang for buck:

1. Fox shocks modified for MHs. Get them from Agile Offroad.
2. Bigger sway bar.
3. Added leaf spring: Supersprings A-11.

A bigger bump stop will do nothing. Fox shocks are your best bet.
calbiker is offline   Reply With Quote
The Following 3 Users Say Thank You to calbiker For This Useful Post:
Bucker (12-03-2017), kmay (10-15-2016), RVMike1 (12-10-2016)
Old 10-15-2016, 02:19 AM   #4
Old Crows
Calypso 2014 View Profile
 
Old Crows's Avatar
 
Join Date: Aug 2010
Location: Texas
Posts: 3,617
Thanks: 8,551
Thanked 1,890 Times in 1,195 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

Well, not knowing your year and model.... presume a Class C RV.

First.... BEFORE you do anything..... look at the tire pressure placard on the driver's side door sill. Do not set your TPs any higher than the suggested pressure for MAX Gross Vehicle Weight Rating. If you know you are a little 'lighter' you may back off a couple PSI. What you want is flexibility in the tire side walls.

The least expensive fix are SUMO SOLOs. Front and rear, although you could get buy with just the rear set up. That's what I have done. And, they kill the rocking side to side in all but exceptional situations. IMHO, you really don't want to increase the roll stiffness with a larger 'sway/roll' bar.

The next 'cheapest' thing you can do is to SLOW DOWN in strong winds. Faster you go, the more force that is generated on the high sides, front and rear of the RV. It already has a high center of gravity so it doesn't need any help to make it unstable.
__________________
"Calypso" 2014 Winnebago View Profile
"Mariah" 2010 FourWinds Ventura
"Globemaster III" 2005 Trail Lite C-17 Hybrid Travel Trailer

Old Crows is offline   Reply With Quote
The Following 3 Users Say Thank You to Old Crows For This Useful Post:
bsemion (04-10-2017), drmoreau (12-13-2017), SneakyAnarchistVanCamper (12-22-2017)
Old 10-15-2016, 02:27 AM   #5
Ovrlnd_Trvlr
On A Journey
 
Ovrlnd_Trvlr's Avatar
 
Join Date: Feb 2016
Location: Lake Superior North
Posts: 328
Thanks: 128
Thanked 75 Times in 60 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

Has anyone here put a set of Timbrens on? I have liked them on other vehicles.
Ovrlnd_Trvlr is offline   Reply With Quote
Old 10-15-2016, 01:18 PM   #6
Denis4x4
2013 Unity TB
 
Denis4x4's Avatar
 
Join Date: Aug 2013
Location: Durango CO
Posts: 445
Thanks: 29
Thanked 282 Times in 152 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

Put Sumo Solos on last year and very pleased with how they perform. Best bang for the buck in my opinion.
__________________
If you don't go first class, your heirs will!
Denis4x4 is offline   Reply With Quote
Old 10-15-2016, 02:50 PM   #7
calbiker
 
Join Date: Aug 2008
Location: Santa Barbara
Posts: 1,809
Thanks: 249
Thanked 804 Times in 536 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

I don't see how Timbrens or Sumos improve handling in gusty conditions. These "rubber" springs do not get compressed when the rig leans slightly from wind push. The springs are not engaged.

You can do a simple test. Push against the side of the vehicle to get it rocking. It will rock at a 1 sec period. The ease at which it rocks is directly proportional to the amount the vehicle gets pushed off its line from wind. I've done the tests and recorded the data. These springs do not help. They have other fine attributes, but they don't help in gusty conditions.

Install the Fox shocks or the S-11 springs and you'll see a reduction of oscillations when pushing against the side of the vehicle.
calbiker is offline   Reply With Quote
Old 10-15-2016, 03:05 PM   #8
Midwestdrifter
 
Join Date: Sep 2013
Location: Ozarks, Waiting for His Van
Posts: 5,387
Thanks: 1,033
Thanked 3,778 Times in 2,272 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

My van (while not a unity) is lifted, top heavy, and weighs just under 9K lbs. Fox shocks made an enormous difference is wind buffeting and handling overall.
__________________
2004 T1N | Overland Conversion in Process Completed...For now... | 101,000 118,XXX 137,078 150,000 miles | 140" | High Roof | My Build Thread
Another Random Blog | http://VagariesAbound.blogspot.com
Midwestdrifter is online now   Reply With Quote
The Following User Says Thank You to Midwestdrifter For This Useful Post:
born2trek (09-30-2017)
Old 11-29-2016, 12:50 AM   #9
ablock
 
Join Date: Aug 2016
Location: Marin County
Posts: 453
Thanks: 58
Thanked 171 Times in 110 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

Did the Fox shocks and Sumo Springs bump stop installs yesterday on our 2016 chassis.

The Sumo Springs were super easy. You do have to jack up each wheel, but after that the job is cake: you could complete it in 5 minutes and have time for coffee. Snap out the old bump stops, push the forward tongue of the Sumo Spring into the slot, rotate the new stop upward until the aft tongue folds itself into place, done.

The shocks were a little more work. First of all, I think I read that the required somewhere socket is 19mm; it's 21mm. Once you have the tools ready (a 50-200 ft-lb ratcheting torque wrench will give you right range), the right side shock is pretty easy. The only challenge is that the modified Fox shocks are so well damped you can't change their length by hand. So you install the upper bolt first, then work the lower shock mount into place. Next, jack up the wheel until the length between the shock mounts matches the shock (i.e., when the holes line up). It took one or two raise/lower cycles to get right but it wasn't frustrating.

The left side is a bit more difficult. On our 2016 there is a linkage for a suspension length sensor (for the ESC?) that is attached to a pin that goes through the upper shock mount. You have to remove the pin to replace the shock ... but the pin is blocked by the sensor mount. The sensor mount is held in place by two 9mm nuts on studs threaded into the frame. Once you remove the nuts the sensor can be removed, but it remains connected by a fragile-looking cable. Removing the small ball end connector from the sensor linkage makes it easier to access the shock bolt. You will need a 21mm open-end wrench to keep the pin from spinning when you tighten the upper shock nut — hold it steady using the flats machined into the pin. Also, you'll need a 4" extension on your torque wrench to clear the tire.

After you reinstall the sensor, the lower mount is easy but requires the same dance with the jack.

The whole project took about 2.5 hours and was definitely worth it. Ride is significantly improved all around: coming out of driveways, cornering, and on the freeway.

Hope that helps someone.
ablock is offline   Reply With Quote
The Following 2 Users Say Thank You to ablock For This Useful Post:
GLHGLH (02-19-2017), kmay (11-30-2016)
Old 11-29-2016, 01:26 AM   #10
calbiker
 
Join Date: Aug 2008
Location: Santa Barbara
Posts: 1,809
Thanks: 249
Thanked 804 Times in 536 Posts
Default Re: Suspension upgrades to improve handling in gusty winds

There is a simpler method to install the lower Fox mounting. The shock has 200 lbs of nitrogen. That makes the shock expand slowly. First install the top bolt. Then wait until the bottom bolt aligns as the shock expands.
calbiker is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 03:40 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.