Turanza gets better
Bridgestone Asia Pacific held a tyre testing session in Thailand recently to burnish the credentials of its latest Turanza series.
BRIDGESTONE might have switched its branding focus from top-ranked motor sports to an environmentally “green” image but it has not altered its status as a reputable and respected tyre maker globally with a strong range of products.
The Turanza is its top range tyre, aimed at the premium class of cars, and the latest evolvement was introduced recently as the T005A.
Changes in current automotive development trends require ancillary components that form part of the automotive chain to keep pace and the tyre is an essential part of that combination.
Based on that target, Bridgestone has come up with a new Turanza that it says provides a quieter, safer and more comfortable ride performance.
To give the regional media a first-hand experience of the improved Turanza T005A, we were assembled at Bridgestone’s proving ground near Bangkok.
This was conducted via four routines but only one enabled the experience to be gained from the driver’s seat; we were ‘chauffeured driven’ for the three others.
The logic behind this assessment was that we could focus on the Turanza’s new qualities while being driven rather than to drive and feel.
As the Turanza is a premium tyre that is suitable for like-status and luxury vehicles, gauging its performance parameters from a passenger’s perspective makes good sense.
The safer performance was arrived at with an optimised contact design, chamfering and new compound; the first refers to the contact pressure distribution and contact shape with the road to improve wet road performance.
Chamfering is applied to the sipe edges on the tyre shoulder, which are rounded to prevent deformation and provide a flat contact area on the road to improve braking performance.
Item three sees a combination of two compounds – silica and polymer – through the application of Bridgestone’s Nano Pro-Tech approach to improve wet performance.
The braking performance between new and old Turanzas is a shorter stopping distance of more than 2m on wet road surfaces for the T005A; this was demonstrated by the Bridgestone staff over a simulated wet road section before the impression routines.
For a quieter performance, Bridgestone introduced high-angle sipes and optimised pitch variation for the tyre tread pattern.
The sipes involved are on the three pattern ribs to the centre of the tyre; the approach is to soften the impact of the tyre on the road and improve pattern noise.
In the second aspect, random and different pitch variation is applied to every tread block so that the tone of each block is varied, thereby reducing pattern noise.
Bridgestone’s tests revealed that the tyre noise generated is reduced by more than one decibel when running over rough surfaces (at 60kph) and smooth surfaces (100kph).
To achieve a smoother performance, the tyre’s contact design is optimised and the sidewall is reinforced for a more sturdy profile.
By optimising the contact design, road contact shape and pressure distribution are better to keep balance between damping and shock at a high level.
With a stiffer sidewall, there is less damping or flexing and this improves ride comfort; however, Bridgestone says this does not apply to tyres with lower aspect ratios.
Our first routine of the day was on ‘Comfort and Silence’ in which we were to observe the difference between the new and the old, the Turanza GR100.
Why does the preceding tyre bears a different name from the new Turanza?
The name follows the different stages of tyre development as well as the place where the development was mostly done.
Apparently, Bridgestone realises the oddity and might toe a singular name for future Turanza models to avoid confusing customers.
Back to the tyre impression sessions; the routine involved two Toyota Camry 2.0G, one with the new Turanza and the other the predecessor (tyre size was common at 215/55 R17).
We were driven over a course twice that had different road surfaces in each of the Camrys and the general consensus was on a quieter running Turanza T005A; for us, it was clearer over the coarse surfaces than the smoother ones, although it was supposed to be the other way round.
Session two was conducted in two BMW 520d for some high speed driving around the 2km-plus oval in which a lane change was made at 140kph followed by a tyre pattern noise observation from 60kph to100kph.
Again the BMW with the Turanza T005A did the 140kph lane change comfortably against a slightly more tail-happy one for the car running on the GR100.
We could also quite clearly discern the lower pattern noise between the two tyres shod to the respective Bimmer.
The third session was wet handling in the Camry 2.0G with the new Turanza T005A on a damp circuitous course; the speed we were driven at was between 60kph and 120kph.
Apart from revelling in the confident manner in which the Camry was driven through the wet course without losing traction, we also came away impressed at how dynamically strong this Toyota sedan was.
Our drive impression was in the Camry through a gymkhana course, beginning with a braking session, a lane change manoeuvre and a slalom section.
We were left to our own on the speed but to a maximum of 70kph; however, we felt the braking experience could be better done with a marker at which we were to brake.
Instead we were told to brake as and when we feel the need to and have the Camry stopped within a designated box.
This confused us a bit as to the basis for comparison; we chose instead to brake when we hit 70kph and see where the Toyota would stop for the respective tyre.
Doing so confirmed that the Camry with the Turanza T005A came to a standstill further from the designated box than the one with GR100.
Likewise, we felt more in control driving through the lane change and slalom on the T005A Camry, confirming its better grip performance.
The Turanza T005A is available here in 16-inch to 21-inch range – 215/55 R16 to 255/35 R21 – and are imported from Thailand, Indonesia and Japan (based on the sizes that are made in the respective country).
Bridgestone Malaysia says the recommended retail price starts from RM437 for the smallest size Turanza T005A to RM1,864 for the 21-inch tyre, which is suitable for the Mercedes-Benz S-Class and BMW 7 Series.