Established since 1976
Established since 1976
By Lee Pang Seng
TYRE development also focuses on regional needs, especially where demand is big enough, and Bridgestone is mindful of that. This was clearly demonstrated in the latest version of its flagship tyre Turanza, the T005A.
Most would think that the model it is supposedly derived from, the T005, would be similar in tread pattern and performance characteristics. But it isn’t and one would be astonished to see how different they are in the tread pattern.
The Turanza T005A that was introduced to the Malaysian market recently was designed and developed to meet the general preference of premium and luxury car owners in the Asean region. Hence, the ‘A’ is part of its name but it is also sold in Korea, India and Hong Kong.
The T005 is generally meant for European and other markets where the tyre performance demands are different. That explains why the T005 is selected as an OE (Original Equipment) fitting for the Lexus LS and Audi A7 Sportback.
While we are on the name, the Turanza T005A was introduced to replace the Turanza GR100. This would stump most on the model progression for this Bridgestone flagship tyre but there is a reason for this.
Tyre development is often conducted at more than one R&D centre and the facility that comes up with the best results would usually be adopted for the updated model. As each centre works on different development platforms, it explains why the model name is different. However, Bridgestone acknowledges that this might confuse its customers and a more consistent model name might be looked into for future products.
The promotional pitch for the Turanza T005A is ‘Comfort Above All’ that covers quieter, safer and smoother performance. This underlines the way tyres are viewed generally in the Asean region. After all, with cars becoming quieter to drive, it wouldn’t do to have noisy tyres to ruin the peace.
Although roads in the region have improved, there are still areas that have less desirable road surfaces. There is also the question of road maintenance where rapid surface deterioration is not matched by the frequency of repairs, leading to less than smooth drives.
While Bridgestone believes that the Turanza T005A would meet the needs of car owners in handling such situations nicely, its wet grip and handling performance are just as good. We could testify to that after experiencing the high performance standards of the new Turanza at Bridgestone’s proving ground in Thailand.
Tyre Perspective
Before we delve into that, let’s look at the respective features of the Turanza T005A that were improved to raise the level of performance. The quieter aspect looks into the optimised pitch variation across the tyre tread surface and high-angle sipes (water channels).
The angle of the sipes on the three middle rows of tread and contact line are adjusted at specific degrees so that it would soften the impact of the tyre tread on the road. Thus, the pattern noise is reduced.
Similarly, applying different and randomised pitch variation to every tread block on the inside shoulder, centre and outside shoulder led to the tone of each block being varied. This was found to dampen pattern noise as well.
Bridgestone trials at the Thai proving ground established that this newly applied technology reduced the sound level as measured from inside the car at being almost a decibel lower when running over rough and smooth surfaces compared to the Turanza GR100. The difference in noise level was greater over rough surfaces.
The safer aspect saw an optimised tyre-to-road contact design, chamfering of the sipes on the outer shoulder of the tyre and the use of a new compound. What Bridgestone has done in the first area is to optimise the contact pressure distribution and contact shape to boost wet grip performance.
The Turanza GR100 has a rectangular contact patch on the road that is seen as not fully consistent although it covers a bigger area. With the Turanza T005A, there is a roundish road contact area that Bridgestone says offers consistent pressure for better road grip.
In the second aspect, the sipe edges are rounded to prevent deformation and ensure flat contact between the tyre and road. This is said to improve braking performance. That is because without chamfering, the edge curves inward and causes floating while with chamfering, there is flat contact with the road.
The new compound combines silica and polymer through the application of Bridgestone’s Nano Pro-Tech. This improves wet performance. Bridgestone says with the normal silica compound, wet performance is enjoyed but bad silica dispersion affects other performance areas such as wear. The Nano Pro-Tech Special Agent could disperse each silica compound evenly to raise wet performance without affecting other areas of tyre performance.
Trials done at the Thai proving ground showed that the T005A stopped two metres shorter on wet road surfaces compared to the GR100 when braking from 80km/h. A demonstration of this improvement was shown during our visit there using two Toyota Camry 2.0G, one fitted with the T005A and the other with the GR100.
For smoother performance, the applied technology saw to the optimised contact patch and reinforced sidewalls. The contact patch is similar to that for the safer aspect and in this case, the target was to achieve an optimised contact shape and pressure distribution to keep a balance between damping and shock at a high level.
The reinforced sidewalls approach is self-explanatory as it means making the sidewalls stiffer (except for low aspect ratios, probably 35 or so) so that there is less damping (or sidewall flexing) to improve ride comfort.
Bridgestone has recorded T005A improvements in five areas of tyre performance – dry handling, wet braking, ride comfort, quietness and wear life – over the GR100 while matching it in fuel efficiency.
Turanza T005A Experience
Apart from observing the wet braking performance, we experienced the improved performance of the latest Turanza in four disciplines. However, we only got to experience it from the driver’s seat in the last session while for the other three, we gained the insight as passengers.
As the Turanza is a tyre aimed at premium and luxury cars, Bridgestone believed that the experience would be more complete if we were to focus on the respective areas as passengers, rather than as drivers. That sounds reasonable and our first run was on a test on our ears.
We were driven in two Camry sedans, one running on the T006A and the other the GR100 (both were 215/55 R17 tyres), over two road surfaces. The speed over the rough surface section was 60km/h and the smooth one at 100km/h. We could discern the quieter ride over the rough surface better as the margin of improvement was higher, while we weren’t too sure over the smooth road.
This was followed by a ride in two BMW 520D sedans, again fitted with old and new Turanza tyres for another comparison impression. We were driven around the 2km-plus oval to gauge the dynamic balance of the Beemer through a 140km/h lane change manoeuvre and a pattern noise section at 60-100km/h to appreciate the quieter feedback.
Needless to say, the BMW 520D running on the Turanza T005A felt more planted on the road taking the sweeping curves at speeds close 160km/h while the 140km/h lane change was conducted without much drama. We could feel the rear lightening up with the GR100 BMW 520D and more rear end movement. The pattern noise section also revealed a quieter T005A against the GR100.
We like the third session the most; this was the wet grip experience with the Toyota Camry 2.0G running on the T005A. This is through a twisty course that we had driven through some years back on cars fitted with Ecopia tyres.
We could tell that the Bridgestone drivers were fully confident of the Turanza T005A when they barrelled into the first sweeping turn that tightens sharply at 120km/h. And he continued the full course of a good mix of corners and cambers at speeds we would be hard put to reach, taking in two laps in all.
The high wet grip quality of the T005A was clearly demonstrated and while we came away fully convinced about the tyre’s performance, we were also impressed by the Camry’s dynamic handling quality. If anything, the car and tyre was a good match.
We got to drive in the final session, a gymkhana comprising a dry braking routine, a lane change manoeuvre and a short slalom. Again the experience was enjoyed in two Camry sedans with old and new Turanza tyres. We were allowed to drive up to a speed of 70km/h.
The braking section was a bit confusing as we were told to try and stop within a dedicated section. That meant we have to decide at what speed to hit the brakes to stop within the box. Instead, we decided to hit the brakes when we hit 70km/h and see where the car would stop. Not surprisingly, the T005A Camry stopped further from the box than the GR100 Camry.
Again, the T005A Camry was more confident taking the lane change manoeuvre (easily above 60km/h) and the steering feedback was sharper for a quicker drive through the slalom. The new Turanza certainly ticked all the right boxes in ride comfort and overall performance.
While Bridgestone Malaysia is focusing on the Turanza T005A tyres for the market, it would also bring in limited volume of the T005 to serve the Lexus LS owners, among others. There are 21 different sizes for the T005A, ranging from 205/55 R16 to 245/40 R20. Prices range from RM437 to RM1137. These tyres are brought in from Thailand, Indonesia and Japan, based on the sizes. For more information, visit www.bridgestonetyre.com.my
