Often referred to as hubs, the upright is the large item that contains the rotating hub and its bearings, and attaches to the wishbones. Nitron are now making available the ultimate upright assembly, for the serious racer, track user or enthusiast.

One of the main problems with the Elise, Exige and other similar cars is that they are designed to run at a fairly high ride height. For track use and sometimes even road use, lowering the car not only makes it look better, but also makes it go round corners better – or rather it should. However, Lotus have optimised their suspension geometry to run at the designed ride height, and lowering the car upsets this. Cars running on stock uprights but with very low ride heights have very poor suspension geometry.

What has Nitron Racing done?

By manufacturing uprights with the hub centre raised by 25mm, the car is effectively lowered by this amount without changing any of the suspension geometry. Any more than this is limited really by the wheels and the wishbones.

Nitron Racing has spent months of design time to arrive at the optimum solution of raised hub, overall weight, increased stiffness, cooling efficiency and overall packaging of the front and rear uprights on the S2 cars (Toyota and K-series). S1 cars will become available shortly.

Design Principle

The design concept was to use the entire upright as a vented spool, as they do on F1 and Le Mans Sports Prototypes. This means that the upright itself is internally vented and allows cold air from an intake duct to be pumped around the bearing, CV joint at the rear, and then into the eye of the disc bell and out through the vanes on the disc. This air is controlled and kept within the upright itself, rather than lost and wasted. A spool design of upright is very stiff by the nature of its own shape.

Nitron Racing kept the Lotus design principle of steering arm, this is very useful for changing the camber settings without affecting the toe setting. We have increased the steering arm mounting base for additional stiffness. The arm has also been optimised for bump steer, this can be adjusted for different conditions, i.e. the Nurburgring to Silverstone, and minimises the bending load on the mounting bolt, all making the driving experience more predictable.

The front uprights take the standard AP or Alcon 4-pot caliper (the original 2-pot will no longer fit), and the rear upright has been designed to accept both the smaller AP 2-pot caliper (originally fitted to the front) or our recommendation of the 4-pot as on the front, as the Toyota-engined cars are now getting very rear heavy.

Finished Solution

The uprights are machined on a 5-axis machining centre to incredible tolerances. They start off as a huge billet of 7075-T6 aluminium and through the very latest CAD-CAM systems they are turned into the finished item. Each upright is on the CNC machine for about 8 hours. Once the upright is finished, it is sent away for hard anodising, then finished off back on the CNC machine to have its holes finish tapped and counter-bored where required.

The upright is then finally assembled with extremely sturdy Titanium stems for the wishbone bearings, and optional Titanium accessories such as caliper mounting studs. The finished item is hugely stiff yet very light. The standard S2 bearing hub pack is bolted to the upright with special bolts included in the kit, new Lotus OE bearing hub packs can be supplied if required.

Installation

To attach these uprights to standard wishbones requires the removal of the original outer ball joints and in their place a steel insert is fitted. This insert then can be fitted with a high quality spherical bearing. If you are using the Full Race T45 wishbone kit, this is not necessary as these bolt straight onto the Ti stems fitted to the uprights.

To compliment the upright, the cooling carbon pack can be fitted as mentioned above. On the front, this comprises two carbon parts per upright. A high temperature carbon disc is bolted to the outside face of the upright, which will seal the eye of the vented disc when it is fitted onto the hub. On the inner face of the upright, a carbon ‘ball’ is bolted which can be connected to a 2” ID silicon brake duct hose (not supplied in the kit). This then allows cold air form a brake duct to be pumped into the inside of the upright spool. On the rear, the idea is the same, but the carbon ‘ball’ has a hole in the centre which allows the CV joint to pass through, which also then benefits from cooling air.

This kit has been tested in the Britcar 6 hour this year and the improvement in geometry removed some of the peculiar handling they were having before with the original uprights. They also benefitted from the improved disc cooling and a reduction in the un-sprung mass.