2023 Lexus LBX unveiled

Jul 28, 2023

In Cars, Global Car Launches, Lexus / By Paul Tan / 5 June 2023 3:21 pm / 30 comments

This is it, Lexus first ever B-segment vehicle, the Lexus LBX. Prior to this, the smallest segment that Lexus has ever played in was the C-segment, first with the hybrid-exclusive Lexus CT hatchback and more recently the Lexus UX SUV. Built on the new GA-B platform (Lexus version of TNGA-B), the Lexus LBX will go on sale sometime in Q4 2023.

The new Lexus LBX measures 4,190 mm long, 1,825 mm wide and 1,560 mm tall, with a wheelbase of 2,580 mm. It is 305 mm shorter han the Lexus UX that is 4,495 mm long. It's also 15 mm narrower than the UX, but curiously it seems to be 20 mm taller than the Lexus UX that is 1,540 mm tall. There's a choice of two alloy wheel designs, a 17 inch wrapped with 225/60R17 tyres and 18 inch with 225/55R18 tyres.

Based on press material, it appears that the new LBX will be available exclusively as a hybrid, and will be available in both front wheel drive and all wheel drive versions. Under the hood is a hybrid system based on a 3-cylinder 1.5 litre engine producing 134hp and 185 Nm. Powering the hybrid system is a NiMH battery, an all-new bi-polar unit with reduced weight and a more compact design. The choice to continue with NiMH is curious as even the DNGA Yaris Cross is now using lithium ion.

To adapt the TNGA B platform for Lexus use, techniques such as short-pitch spot welding and expanded use of structural adhesives were implemented in the appropriate areas. Additionally, the structural adhesives in areas closer to the occupants were strategically replaced with high-dampening adhesive, thereby reducing vibration in the high-frequency ranges. This significant reduction contributes to improved driving stability, ride comfort, and substantial reduction in NVH levels.

Various measures were implemented around the engine, such as optimised placement of engine mounts to minimise shock during startup, incorporating a balance shaft with the engine to dampen low RPM floor vibrations, and adding a resonator to the air cleaner hose to diminish intake noise.

For the exhaust system, a flexible pipe has been added to reduce vibration from the engine, and the main muffler capacity has been increased to lower exhaust noise. Furthermore, by adding an additional sound- absorption layer to the two-layer inner dash silencer and creating a three-layer structure, the thickness and density of the layers are optimized, thereby enhancing the sound absorption and insulation performance. 


Vibration is efficiently suppressed without the use of heavy materials by incorporating a high-dampening type of mastic sealer for a portion of the roof panel, resulting in a quieter cabin when driving or in the rain, as well as a lower center of gravity due to weight reduction. 


In addition to joint rigidity, focus was also placed on peripheral rigidity in key areas. The cowl structure connecting the front suspension towers was reworked to enhance rigidity at the load-bearing points. Reinforcement of the instrument panel structure boosted both steering column and instrument panel reinforcement rigidity. This resulted in exceptional steering response while decreasing unwanted vibrations transmitted through the steering system. 


A lightweight construction and exceptional rigidity was achieved through strategic placement of the roof reinforcement to reduce the overall thickness of the roof panel. Additionally, the use of aluminum for the hood and 2.0 GPa grade hot-stamped material for the center pillar, as well as 1.8 GPa grade hot-stamped material for the front bumper reinforcement, contribute to a high level of safety performance. The optimization of inertial characteristics, including the lowering of the center of gravity further enhances handling stability. 


The front suspension features a newly developed MacPherson strut suspension with updated suspension geometry. The large 
caster angle ensures excellent straight-line stability, suppresses toe-in changes during body roll, and minimizes understeer. This results in solid and confident linear control over vehicle posture during cornering.

A highly rigid forged aluminum knuckle is employed for the front suspension knuckle to reduce unsprung weight. In addition, the newly developed input-separation type upper support with three-point attachment contributes to both linear steering response and refined ride comfort. 


Front wheel drive versions of the LBX use a lightweight and rigid torsion beam, while AWD models use a trailing arm type 2-link double-wishbone suspension that houses the rear hybrid motor. The newly developed shock absorbers use quick reacting sliding components to ensure dampening force at very low speeds, as well as a high level of both maneuverability and ride comfort. 


Premium brands very rarely go smaller than C-segment, so it's interesting to see how Lexus will fare with the LBX. At the moment we only have the Audi A1/Q1/Q2 and various models from MINI as its competitors.