Bigger sized tyre for Punto Active
I own a Punto Mjet Active and for quite some time now, have been toiling with the idea of using bigger tyres after the current OEM JK Tornado's are worn out. This is because Punto does not have a very good Ground clearance as it has the engine guard plate which is placed low under the car and also has a long nose which poses a problem when encountering slopes. The long wheelbase, as compared to other hatches also poses a problem when moving over inclines which have a triangular head. I am a careful driver and know how to tackle huge bumps, etc. However, there are situations when all this does not help and the car gets scraped in its underbelly. I am fed up the roads and as I do not have any control on the roads and the unpredictable potholes, I feel like giving my car bigger shoes so that it does not hurt itself. I have read about the pros and cons of having higher side profile / lower side profile, fatter tyres / leaner tyres in terms of the contact patch etc.
This is what I have learnt -
Higher or more side profile - The tyres would be able to absorb more of the shocks transmitted by potholes and bad roads. Advised for Indian roads.
However, there is more chance of sidewall cut due to bad roads / pebbles / stones.
Lower or smaller side profile - The car feels as if it is riding on rails. Car is more planted & body rolling is reduced. However, the disadvantage is that tyres do not absorb much of the shocks transmitted by potholes and bad roads. Might affect the suspension setup as more shocks are transmitted to the suspension.
More contact Patch - 195 section, 205 section etc - Provides more grip to the car. Allows for more control on the car during spirited drives. However, the steering might feel havier and the mileage would get reduced due to more friction on the tyres. Looks better on cars.
Less contact Patch - 165 section, 155 section etc - Less grip on the road, lesser control during spirited drives. Steering feels lighter and mileage is not affected. Does not look too good on cars.
However, even after going through the information regarding using bigger tyres, having bigger overall diameter, I am unable to decide on what to do. This is what I understand -
1> A bigger radius tyre would increase the ground clearance by the same measure as the difference between the stock tyre radius and the bigger tyre radius
2> The car would cover mode distance with less work done by the engine. Car would be at a higher speed at a lower RPM.
3> For the same amount of diesel, the car would cover more distance. Of course, during city drives, this might not be observed as the engine would have to exert more for turning the bigger tyres. However, on highway runs, this would save on fuel. I am more of a highway guy, don't use the car much inside the city.
1> Bigger turning radius - The car would need a bigger radius to turn. For tight spots, this might pose a problem.
2> Speedometer error - The speedo would show a lesser speed when the car is travelling at a higher speed. All the functions of the tripmeter on the Punto would get affected (For example - distance covered, distance to empty, speed, mileage, etc)
3> The car would get more sluggish on bumper to bumper traffic and would sip more fuel as it needs to turn a bigger tyre.
4> As the car is riding higher now, the stability is compromised. Body roll would also increase.
5> The tyre might touch the inner walls of the wheel well when tackling bumps or when fully loaded.
From my point of view and my driving style and my highway usage, I feel that going for bigger tyres should not be a problem. For sure, the number of potholes & huge bumps is very less on highways as compared to inside cities. However, there are situations where a higher gc helps. Moreover, I am a very sedate driver. On open highways, I never stretch beyond 100 km/hr. Thus, would request everyone to pool in with their comments so that even if I don't upgrade to bigger tyres, I am able to convince myself that sticking to the stock size or a little above it, is the right decision.
Stock Tyre - 165/80/R14 Radius - 309.8 mm
Upgrade - 195/65/R15 Radius - 317.2 mm Difference in radius is +2.38 %
I am aware that it is recommended that the tire size difference while upgrading should not exceed more than 2% when upgrading from stock.
So, would it be ok if I go for Upgrade - Bridgestone B250 195/65/R15 ?