OFFICIAL BUSRide Road Test: The 2014 MCI J4500
New brake, axle and suspension systems reflect MCI’s attention to technical and mechanical detail
By David Hubbard
The strategic effort by Motor Coach Industries (MCI), Des Plaines, IL, to bring its J4500 and D-model coaches closer together has been a work in progress since 2008. According to the company, its mission has been to unify the componentry and systems in terms of manufacturing
Improvements and new features of the MCI J and D models reflect MCI’s attention to technical and mechanical detail. Unlike the recent restyling of the J4500 model, these updates are not about curb appeal.
“We are out to improve both functionality and performance in both models,” says Brent Maitland, vice president, MCI Marketing and Product Planning. “By increasing the commonality of these key systems, we create efficiency in engineering, improve our manufacturing, and make parts that service easier for our customers, with the overall result
being improved reliability of our product.”
The move to ZF axle and suspension
The central focus to this significant upgrade has involved the incorporation of ZF axle and independent suspension system that promises to significantly reduce the turning radius and smooth out the ride. ZF Industries, Vernon Hills, IL, (ZF Services) or ZF North American, Northville, MI, manufactures these products in Gainesville, GA.
The company notes the key features of the ZF RL 80 E Independent Front Suspension:
• The capability of a high wheel cut of up to 60 degrees – 55 degrees in the MCI
• The manner in which the suspension upright separates the steering forces from the axle road forces allows a quicker response of the suspension and more precise steering.
• The double–wishbone design with maintenance-free rubber-metal bearings at the mounting points and wheel ends with unitized bearings reduce maintenance costs.
• The systems are lightweight and maneuverable.
MCI says it decided to move to the ZF system two years ago, which takes the MCI models from solid beam to independent suspension.
According to Maitland, the weight reduction with the new axles and suspension systems allows approximately 700 more pounds in payload.
Bendix Air Disc Brake
The new coaches offer the proven Bendix Air Disc Brake (ADB) 22 X brake system, made in the U.S. since 2005, which will also offer the additional safety of adaptive cruise control.
Maitland says this undertaking is more than just plugging the new systems into the MCI platform.
“This type of project requires engineering and testing as there are modifications to integrate the systems into the coach structure,” he says. “This is where the design and testing comes into play. We need to thoroughly understand how the changes affect the coach performance and ride dynamics.”
“The advantages of an independent suspension system are no secret to the industry,” Maitland adds. “In our application, it offers significant improvement in terms of ride quality and feel, as well as a much tighter turning radius.”
According to MCI, the current standard turning radius on the J4500 model is roughly 47 feet; 45 feet with optional rear-steering. The new J4500 with ZF is 40 feet, 11 inches.
“While the ZF axle system makes the coach significantly more maneuverable, it may require some additional training for drivers,” Maitland says. “But ultimately, they will enjoy many major advantages.”
To help prove the reliability of the systems, MCI sent the J coach to the arduous Bosch Durability Testing Facility, New Carlisle, IN, where techs put it through the equivalent of one-million miles of wear, tear and abuse over 10,000 miles of actual track mileage.
“They pounded the coach over cobblestones, chatter bumps and other features designed to stress the system,” Maitland says. “They beat it up pretty good. Also a testament to the design of our J is that we’ve used the same coach through multiple durability tests and it just kept ticking for millions of miles of real world equivalent testing.”
With these technologies already proven in other heavy-duty commercial vehicles, MCI has built 12 pilot J4500 coaches featuring the ZF and Bendix systems, nine of which are in service with MCI operators across the country for independent field testing in everyday highway conditions and normal operations.
“We are doing thorough testing and we look forward to getting detailed feedback from these companies,” he says. “For instance, a maintenance tech may notice some minor difficulty in reaching a new part or fitting that we can still address.”
Arrow Stage Lines
Arrow Stage Lines, a longstanding MCI customer headquartered in Omaha, NB, with operations in 11 locations, is one such company to test drive the new J4500. BUSRide called on Arrow Stage Lines, Kansas City, MO, for a report of its early experiences.
Dave Zibro, a seasoned driver of nearly every sort of commercial vehicle for most of his life, was the first of four Arrow Stage drivers to take the J out on the road for charter service.
He transported the Columbia High School Choir on a six-day trip from Kansas City, MO, to Nashville, TN, which he says presented a tremendous opportunity to experience handling and maneuverability in assorted weather from clear skies to wind and rain.
“I noticed a difference on the very first turn out of our yard,” Zibro says. “At that point I was not aware of the steer tag axle, but I felt the difference immediately in that quicker turn with less tail swing. For the rest of the trip I couldn’t ask for the steering and handling to be any better. It’s a wonderful ride.”
Recognizing this is a new model J, Zibro says he is anxious to see how its holds up after 40,000 miles. Considering its performance on the Bosch test track, he should have no complaints.
“I especially like how the front seems to turn shorter than previous MCIs I have driven,” he says. “With the rear axle steer providing greater maneuverability, I was able to get into so many places that would be much more difficult without the steer tag.”
MCI says the tighter turning capability with the help of the rear steer feature should reduce tire wear.
During one of the choir performances, Zibro conducted his own informal test in the parking lot to get a better sense of the tighter turning radius.
“I simply lined up the coach up with the painted lines and made a sharp left U-turn,” he says. “I didn’t take and accurate measure, but the radius was considerably less than anything I had experienced in our other coaches. Maneuvering in traffic around town and in parking lots was a pleasure because it was so easy. I was very glad to have this coach in Nashville for the week.”
One of Zibro’s additional responsibilities is to test-drive various coaches in the Arrow Stage fleet and keep copious notes on what he finds needing attention.
“I have found nothing to make note of,” he says. “This coach is a dream to drive.”
While charter customers may not be cognizant of the technology and componentry responsible for the easier handling and smoother ride, Arrow Stage Vice President of Sales Chuck Gunnels believes it contributes to their improved rider experience.
“Coach passengers are certainly aware of how their driver is performing,” he says. “If he is not having to back up as often in tight situations, and the ride goes generally uninterrupted, they feel more secure and are more at ease.”
Arrow Stage Line Director of Maintenance Wade Freeman says that in the time Arrow Stage has had possession of the pilot coach, he has not seen or heard anyone reporting a mechanical issue.
“Generally, the set up on this new J4500 is much preferable over previous models, particularly the Bendix brake system,” he says. “I particularly like the use of unitized wheel hubs on the steer and tag axles. They can be easily changed out in the event of wheel-bearing issues.”
Service requires replacing only the bearings rather than the entire hub, and there is one common rotor part rather than two.
“We strongly believe that the fundamental design of the bearings and wheel ends are going to keep out significantly more contaminates,” Maitland says. “They are more reliable, which owners will appreciate.”
Several recent features that followed onto the ZF are also worth noting.
The new air suspension system introduced on the J4500 allows the coach a high-low functionality it did not have previously, and gives the coach full front-rise capability.
Maitland says the fundamental design of the independent suspension system allows one inch lower kneeling, while the more efficient air system introduced on previous MCI coaches responds faster to lowering and rising
Bendix Brake ADB System
According to Maitland, the Bendix ADB system will feel more like automobile brakes.
“We feel these brakes should be an easier adjustment for new coach drivers used to an automotive feel,” Maitland says. “The actual brake performance is roughly the same, but the stopping distance is way less than FMVSS standards.”
MCI says it is moving to include the Bendix Wingman System, which offers adaptive cruise control, as well as collision mitigation.
“These functions are becoming more common in the automotive market,” Maitland says. “We think this is a very important safety feature that we can bring to MCI coaches.”
The Bendix adaptive cruise control detects a coach’s position behind other vehicles and automatically reduces the throttle or applies the brakes to maintain safe following distances.
It is also billed as improving the functionality of cruise control and fuel economy.
Coaches are in testing with the Bendix System, and when MCI determines it is ready, the system can be retrofitted into the new ZF-fitted pilot coaches for customer feedback.