Inverted Portal Axle for Neocity Bus

CASE Study #3

Independent Front Suspension and Rear Inverted Portal Axle
for Neocity Bus Family


The case analyzes BRIST’s contribution to Neocity Bus. Scope of supply included both front and rear axles. In front, BMC used off-the-shelf independent front suspension of BRIST. However, in rear, they requested a new development: An inverted portal axle for 19.5″ rim size.

BMC is one of the leading automotive companies based in Turkey. They produce various vehicles such as buses, trucks, pickups and defense applications.

With their multinational Turkish-Qatari shareholder structure, BMC has been active in both domestic and international markets.

Design Challenges

There were 2 main challenges in this project.

First challenge was to develop a drive axle to fit in various engine options on a common LF bus platform. Drive axle should fit all 1) cylinder diesel, 2) cylinder diesel and 3) CNG engine option.

And the second challenge was the integration of BRIST independent axle into the same platform.

Our Solution

BRIST solution provided couple of advantages. First, new radial air brakes enabled a maximized corridor width. Second, BMC achieved a lower axle weight, since the design was specifically developed for 19.5″ rim-size. Third, newly developed main beam provided enlarged ground clearance.

All in all, inverted portal axle was engineered at lowest silhouette possible for BMC unique enquiry.

With its unique input angle (75°); the rear portal axle did not only enable BMC to fit in the tight volume allocated at the rear compartment, but also optimized the layout for 3 different engine options.

Our Value Add to BMC

Until BRIST portal axle, available 19.5″ portal axles in the market were only cut-off versions from 22.5″ portal axle. Thus, they have always been oversize axles in terms of load, cost and efficiency.

With BRIST products, BMC achieved a lighter and better solution, since it was a specific portal axle design for 19.5″ rim-size.

Furthermore, they have also received Best Design Award of Busworld 2017 with Neocity Bus Family.

Vehicle & Products

Independent Front Suspension and Inverted Portal Axles

BMC Neocity has received Busworld Best Design Label in 2017