| A | B | C | D | E | F | G | H | I | ||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Designer | General Motors | Leigh Harrison | Jim Kanomata | Zeb Frady | Dan Hensley | Silver Motor Coach | Todd Sullivan | Alex Sirum | |
2 | System name | OEM | Four Bag | Quadra Bag | Southland | Hensley | Silvertone | SullyBilt | ||
3 | Year introduced | 1973 | 1995 | 2010 | 2011 | 1991, 2011 GMC | 2011 | |||
4 | Bags per side | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 2 | |
5 | Bag manufacturer | Firestone | Firestone | Firestone | Firestone | Firestone | Firestone | Firestone | ||
6 | Bag part number | 8301 | W01-358-3400 | W01-358-7325 | W01-358-9294 | W01-358-7325 | ||||
7 | Bag vendor, USA, retail | none | Leigh Harrison, generally orderable | Applied GMC, COOP, Alex Sirum, Grandview, MGM, generally orderable | Southland Motorhome Center | Applied GMC | generally orderable | Applied GMC, COOP, Alex Sirum, Grandview, MGM, generally orderable | ||
8 | Bag price w/o shipping, each (date) | n/a | $105 (Jan 2015, truckspring.com) | $98 (Jan 2015, appliedgmc.com) | $300 (May 2011) | n/a | $151 (Jan 2015, truckspring.com) | $110 (Jan 2015, truckspring.com) | ||
9 | Max height under bogie | |||||||||
10 | Min height under bogie | |||||||||
11 | Bag pressure at max height, psig | 105 | 88 | |||||||
12 | Bag pressure at normal ride height and weight, psig | 80-90 | 100-110 | 80-90 | 90 | 90-100 | 70 | 60-65 | ||
13 | Leveling range, inches: +up, -down | full: +4, -4 | reduced: +3, -4 | full: +4, -4 | reduced: +3, -4 | greatly reduced | full: +4, -4 | ~ full: +3.75, -3.5 | ||
14 | System vendor | none | Leigh Harrison | Applied GMC | Southland Motorhome Center | Dan Hensley | Applied GMC | Todd Sullivan | Alex Sirum GMC Motorhomes | |
15 | System vendors, other | GMC COOP, Alex Sirum, Grandview, MGM | ||||||||
16 | System price w/o shipping, both sides (date) | n/a | $1075 (Jan 2015) | $1598 (Jan 2015) | UNAVAILABLE? (Jan 2015) $750 (Jan 2012) | $600 (Jan 2012) | $690 (Jan 2015) | $702 (Jan 2015) ($400 galv brackets + $302 bags) | $849 (Jan 2015) | |
17 | System weight | 57 lbs | ||||||||
18 | Shipping price, ~2000mi USA | n/a | $50 | $34 + bags | ||||||
19 | Time to install, both sides | n/a | 4-6hrs | 4-6hrs | 1hr | 1hr | 1hr | 1hr | ||
20 | Ease of installation | n/a | straightforward but some difficult to access and/or high torque work | straightforward but some difficult to access and/or high torque work | simple, bolt-on | simple, bolt-on | simple, bolt-on | simple, bolt-on | ||
21 | Systems installed (date) | 12,921 (1979) | 200+ (Jun 2011) | 12 (Jun 2011) | 5 (May 2011) | 5 (Jan 2012) | ||||
22 | Design features | • should survive loss of single bag per side (2x load on remaining bag and tire!) | • should survive loss of single bag per side (2x load on remaining bag and tire!) | • can travel with bags deflated, ~2" clearance between tires and wheel wells | • bags have internal bump stop (can travel with bags deflated?) | |||||
23 | Reviews, fans | • improved handling (esp for towing) • good protection of hoses and bags from road debris | • improved handling (esp for towing) | • rides like OEM | • rides like OEM | |||||
24 | Reviews, skeptics | • firmer ride than OEM • isolated report of damage to center support under extreme road dynamics | • firmer ride than OEM | • rides like OEM | • question about side-load stresses | |||||
25 | Notes | • bags no longer manufactured • some NOS bags are still available but cost prohibitive (e.g. Cinnabar, $700/ea?) | • adapted from Harrison design with many updates (details?) | • some portion of the system is claimed to be patented, but cannot find confirmation or details • Southland is only US distributor for bag, but it is said to be common in international trucking use • website is damaged, but shows no indication of continued GMC business (Dec 2012) | • bag/cone system original on Silver MC vehicles in 1991 • repurposed for TZEs in 2011 • future availability and current bag age uncertain | • modification of Mark Grueninger design • mounting plates available in multiple materials, finishes, and colors; price is for galvanized steel • Sully does not sell air bags; order them online • Sully encourages home-fabrication of his design, plans are available | • site says "new style" air bag system in stock, no link or info (Jan 2012, Dec 2012) • link to photo gallery added (Sep 2013) • bag part number read from photo in gallery (Sep 2013) • price is for "complete system", which I interpret to mean "both sides" | |||
26 | More information | Leigh Harrison product page | Applied GMC product page | product page offline (Jan 2015) | Applied GMC product page | bdub.net/sully product page and installation instrux | Alex Sirum GMC Motorhomes photo gallery | |||
27 | installation instructions (PDF) | GMC ES presentation (PDF) | installation video | |||||||
28 | air bag data sheet 3400 (PDF) | air bag data sheet 7325 (PDF) | air bag data sheet 9294 (PDF) | air bag data sheet 7325 (PDF) | ||||||
29 | bellows data sheet 224 (PDF) | bellows data sheet 26 (PDF) | truckspring.com air bag spec sheet |