Tread Beyond Roads

Our new series on off-road modifications kicks off with a look at wheels and tyres

BEING IN THE BUSINESS OF MODIFYING vehicles for off-road application presents one with an opportunity of meeting people from diverse backgrounds, age groups and professions. The shared interest among most enthusiasts is an unflinching desire of owning and driving a vehicle, which gives them the ability to undertake journeys beyond conventional roads. While satiating this desire of off-roading, as is the case with most vehicles, the owners are also desirous of making their vehicles unique and an extension of their own style.

Some of these individuals are first-time owners of off-road vehicles and are clueless about their own abilities and their vehicle’s off-road capabilities. So if you are on a path that leads you and your vehicle off-road, it is always great to start with understanding your vehicle’s limitations before undertaking any serious modifications.

If you have a stock off-road vehicle, the first thing that I would advise you to do, is to take your vehicle to the trail and gain some off-road driving experience, preferably along with experienced drivers. This experience will help you make a better assessment of how far you want to go down the road of modifications. The journey down this road can be, and generally is, a very long and expensive one. One modification leads to another, and before you know it the ‘plain jane’ off-road vehicle becomes a trail-munching monster. Having said so, I must also confess, the journey down this road is most gratifying and involving, one which will build memories. In most cases, stock off-roaders are capable enough to tackle most trails with consummate ease. If you are ready to push yourself to go beyond the trails, then you should first begin with the very essential.

My recommendation is to start with tyres, as most manufacturers compromise on these and shod their vehicles with Highway Terrain (H/T) tyres. If you are the adventerous type, then go for All Terrain (A/T) tyres, as these offer a good mix of off-road capability and on-road ride. For more serious off-roading, aggressive tread Mud Terrain (M/T) tyres are the way forward. The caveat here is while M/T tyres look great; they are rather uncomfortable and noisy on road, and also don’t handle very well on wet tarmac. So be very sure what tyres you are choosing and the consequences thereof.

If you are changing tyres, upsizing for better ground clearance is an option that you should actively consider. While upsizing, remember that tyres are an integral part of the drivetrain and cannot be randomly upsized to any size of your choice. There are several parameters that need to be considered while upsizing the tyres, with final drive ratio being the most important one. For the same gear ratio, as the overall diameter of the tyre increases, the effective gearing gets taller, resulting in slower acceleration and overall performance drops, making the vehicle rather sluggish. Therefore, beyond a point, if you increase the size of the tyre too much, you would need to lower the gear ratio. From my experience, most stock vehicles can handle 5 per cent to 6 per cent increase in the overall tyre diameter without having to change the gear ratios.

While on the topic of tyres, it is but natural that one would explore the options available for wheels. In my opinion, changing rims probably ranks among the top three options that new vehicle owners evaluate along with in-car entertainment (ICE)/ in-car infotainment (ICI) and tyres. And rightly too, as a good set of wheels has the most apparent impact on the overall look of the vehicle. But again, selection of wheels has more to do with application than with aesthetics.

There are three very important parameters that one needs to be aware of: the diameter of the wheel that needs to match that of the tyre selected; width of the wheel that should typically be 70 – 80 per cent of the tyre width; and the wheel should have proper offset/back spacing. The last parameter is where most people make an error. Though for proper handling and steering it is preferable to keep the wheel offset close to stock, but for accommodating larger (wider) tyres, one has to consider using negative offset wheels to ensure the tyres don’t foul with the vehicle components. Getting the correct offset wheels requires careful measurement of the existing tyre/wheel fitment and calculations. This is where we start sharpening our pencils.

With proper selection of tyres and wheels, one of the most significant modifications to your off-road vehicle has been accomplished. Well done, for the journey has just begun. From here we would go to addressing suspension related modifications and the requisite protection that needs to be in place as you go on to attempt tougher trails. Tread safely and responsibly! ⌧