No matter what you ride, how hot it looks, what pulsating performance it boasts of or what joy it gives you, the bottomline is that unless you use rubber wisely, you are bound to have an accident. And one has to take extra caution when riding motorcycles since you aren’t cocooned in a metal box that protects you in times of trouble. And hence we as journalists emphasise the quality of the rubber used on a motorcycle as it is the only piece of equipment that should be in contact with the asphalt on most occasions. Hell, most of my long term reports of my Yamaha YZF-R3 have been focused around tyres and if you read our last month’s issue, you would know that I specced out the bike with some new boots.
Well since we do voice out our opinions on your favourite rides and all things that go along with the package, TVS Tyres found it only fitting to call us in and explain what exactly goes into the making of tyres. A couple of flights from Pune and I find myself in its Madurai plant, with little inkling as to what I have in store over the next couple of days.
There is never enough rubber…
A part of the TVS Group, TVS Tyres is TVS Srichakra’s tyre division which primarily produces tyres for two and three wheelers as well as for commercial vehicles. Talking about sheer numbers, TVS Tyres produces close to 2.5 million tyres a month from its two plants in Madurai and Pantnagar, Uttarakhand. And they say that that’s not enough. The demand is ever increasing and hence they are setting up another facility in Madurai itself to meet those numbers.
Currently TVS Tyres occupies a market share of 41 per cent when it comes to supplying for OEMs, a leader of the Indian market by a good 10 per cent over the good folks in Chennai. And it does not stop only at OEMs, their after-market figures are great as well. They have over 3000 distributors and dealers that sell their tyres pan-India.
A major accolade that TVS Tyres can boast about is that all the Michelin rubber that is used on two-wheelers in the country come from their plants. So the next time you are running your Pilots or your Siracs, do remember that they are made right here in India.
Where the magic takes place
I was more or less familiar with what goes into constructing a tyre. Reading about them and being an ardent follower of MotoGP, I did get my basics on tyre construction sorted out. However, I had never been to an actual tyre manufacturing facility and to see them actually starting out from raw calendars of rubber to the finished tyre was quite enlightening. The process begins with raw rubber being heated and impurities in the raw material being removed. The semi-solid rubber is then passed through a series of rollers to be converted into sheets. The sheets are further slimmed down and conveyed onto a unit which adds the nylon fibres.
Each one of these sheets gets a special colour strip through the length of it as it colour co-ordinates to the specification of tyre that is going to be produced. So the next time you buy a brand new tyre, the coloured line, off the centre, is usually the marker for the company for them to process things smoothly. The process is finished off after cooling down the rubber and wrapping them into calendars, ready for production. Now from here, the calendars are transported off to the actual construction area.
If one knows their rubbers, tyres can be classified into two types – Radial and Bias-Ply. Radial tyres are known for their better dynamics as it allows for slip angle to be introduced. Slip angle allows the tyre to deform from its usual shape and help riders with more contact patch when the bike is leaned over. This allows riders to carry extra lean and more speed through the bends. The only downside to radials is they are slightly stiffer in ride quality. Hence, you will find most of your motorcycles up to 250cc running with Bias-Ply tyres. The tyres are softer and allow for a more pliant ride. They are also cheaper to manufacture and last longer in comparison to radials.
Once the carcass and the tread sheets have been rolled into one, the unit is sent for vulcanisation. Sealed in a metal mould, the rubber is forced to expand into the grooves of the mould that would ultimately turn out to be the tread design on the tyres. The mould contains the inscription that you usually find on the sidewall of the tyre like profile, speed rating, date of manufacture and rotation direction. These are then sent for quality control where the excess thread shavings are shaved off and then they are balanced. Finally, the tyre is ready for shipping or could be selected for rigorous testing.
TVS Tyres has been making Bias-Ply tyres for a long time. They have just started making radials under the product name of Protorq. Currently, they have just launched a 140-70/17 size to be used on the rear wheel and it is only available in the aftermarket sector. The tyre should be capable of handling motorcycles of engine cubic capacity of 150-250cc, targeting the likes of Honda CB 160 R Hornet and Suzuki Gixxer 150. They have plans to introduce a couple of sizes for the front tyre as well as one capable to handle duties on a KTM 390 Duke.
Learning To Test
The tyres that TVS does produce are extensively tested out by a group of endurance riders for longevity. However, the final stamp of approval is given by Hide Okamoto san. We were lucky to pick his brains out for a couple of hours following which we hit the test track. Instead of leaving us all out on the track for a couple of hot laps, Hide san took turns in explaining out how to evaluate tyres and what goes on behind the scene.
His job is to evaluate whether the tyre fits the description that the manufacturer gives. Good and bad goes out of one’s dictionary when he/she becomes a tyre tester. So, what does tyre testing entail. Given our limited time the sessions were curbed to four quick ones. Most tyres can do the job in a straight line. It is when the bike starts to lean over that the tyre earns its reputation. A tyre tester needs to evaluate whether the bike leans over quickly or is sluggish, whether the tyre forces the bike to run wide or in fact sharpens the turn, and lastly how stable does the motorcycle feel when leaned over. All this is tested out at relatively lower speeds of 20-25kmph. The best way to test it out is by doing a figure of eight over and over again.
The motorcycles that we tested out the tyres on were the trusty Honda Activa, the Bajaj Platina and the Honda CB Shine 125. The trick was to learn on the Activa while we were to narrate how different the Platina and the Shine behaved when carrying out the same task. It was more like a small class test to check whether we had been paying attention all this while or not.
TVS gave us an opportunity to try out their Protorq tyres, the bias-ply ones and not the radials I mentioned earlier. These too have been designed for the same audience but we tried them out on a KTM 390 Duke. I would refrain from commenting on said tyres as they were not intended for the Duke. Going forward, these tyre testing skills should come in handy when I do evaluate motorcycles.