[locusjag]

There is an optimum ratio of the car's wheelbase to its width. This also contributes to its handling abilities. I wish any automobile engineers here would give out what that optimum ratio is. I heard about it in passing from an automobile engineer myself.

[tirumalavoleti]

For India, there should be enough sidewall. No questions and No arguments.

One big pot hole, the sidewall tears apart on low profile tires.


All the manufacturers going for low side profile is a pity situation.

I have Honda city with 16 inch wheels with very less side wall. The side wall got crack on the third day of car delivery. Felt very sad and show room does not replace as its damage.

Tried to swap to R15 from lower variants but could not get any. Hence upgraded to 195 width which added 5mm more sidewall. The ride is better and worry from side wall vulnerability.

For me handling comes with better tuned suspension, proper length/width ratio (Unlike the abused sub 4 mtr SUV models)

Sorry to say: It makes no sense in India for providing low side wall

[Altocumulus]

I am all for comfort however hate bodyroll. I would do what it takes to get a good balance. I would also add grip to it as well. Both by cars have upgraded tyres, changed on the day of the delivery to ensure there is a balance between ride, handling and grip. Atleast as much is possible keeping the warranty intact.

[BlackPearl]

Voted for "Any, It largely depends upon the car." I would like taller sidewalls and better ride quality in a 4x4 SUV, but better handling in a hatchback/sedan. Taller sidewalls in SUVs are better for off-roading and I would easily compromise on handling for peace of mind.

[Kosfactor]

In the Indian context , aren't they the same thing? The better riding car also happens to have better road grip on uneven roads.

The stiffer sprung vehicles in general feel skittish on less than perfect roads.

Back in the days people who drive a lancer for the first time in the questionable Kerala highways will shake their head in disbelief - what a road grip! I guess they meant ride and handling in one word.

[hridaygandhi]

Although I would love to have a better handling car, it simply does not make sense on Indian roads. I am more careful driving my BMW X1 than my Honda Jazz on our roads, despite the former having a higher ground clearance, purely because of the low profile tires.

In the second month of purchase, the X1's tire gave way on a "normal" (according to Indian conditions) pothole, when it crashed through it at 60 kmph in the middle of the night. Not to mention the cost of replacing larger tires, reliability is definitely more important for me.

[ButterRider 7]

Voted for big wheels and lower profile tyres as, apart from doing wonders for the looks of your car, low profile tyres offer greatly improved levels of handling and grip, especially in the dry. Your car will also brake much better, with a wider contact patch (the area of the tyre in contact with the road) that provides greater traction than a conventional tyre. Low profile tyres will benefit your car's cornering characteristics by being able to handle greater cornering forces (CF), and steering performance sees a marked improvement as well.

[venkyhere]

Originally Posted by ButterRider 7

Voted for big wheels and lower profile tyres as, apart from doing wonders for the looks of your car, low profile tyres offer greatly improved levels of handling and grip, especially in the dry. Your car will also brake much better, with a wider contact patch (the area of the tyre in contact with the road) that provides greater traction than a conventional tyre. Low profile tyres will benefit your car's cornering characteristics by being able to handle greater cornering forces (CF), and steering performance sees a marked improvement as well.

while the science and tech that actually mathematically models tyre grip is closely guarded by the industry (unlikely to find much authentic info) , it is generally understood correctly (out of experience rather than from the math) that wider tyres means more grip. However, contrary to widespread belief, that is not because wider tyres increase the contact patch area. They don't, strictly.

From simple high school physics we can deduce that :
weight pressing on tyre from top = reaction force from the ground upwards = area of tyre contact patch x air pressure inside tyre + tensile resistance force offered by the tyre's sidewall.

Consider a 185/55/15 tyre and another 225/45/15 tyre, made from the same compound. Both have crudely identical same sidewall height (0.5mm difference). If the above equation is applied to both these tyres, we can eliminate the difference from sidewall tensile resistance. That means, inadvertently, the area of contact patch has to be same, if both tyres are filled with the same air pressure and mounted on the same car.

So what's different between the 185 tyre and 225 tyre in this scenario, if the area of contact patch is same ?
The aspect ratio or shape of the contact patch rectangle (if you can call it a rectangle) is different. The 185 tyre one would be more 'squarish' and the 225 tyre one would be more 'rectanglish'. The latter is the desirable thing, when cornering, and that is why wider tyres immediately feel better on the steering. The more rectangle the shape is, the better the lateral grip on offer, for the same amount of lateral load change that happens between left and right tyres.

[S15]

I think the trend has now gotten a little out of hand.

That creta, in particular is hideous. And that Thar with 24 inchers.

[krishnaprasadgg]

Originally Posted by S15

I think the trend has now gotten a little out of hand.

That creta, in particular is hideous. And that Thar with 24 inchers.

I wonder what kind of havoc it unleashes on the diff and other components and I guess the odo reading and speed sensors might go for a toss maybe? That might mess up ABS ESP and other assisted system too right?

Cheers
Krishna

[venkyhere]

as JamesMay would put it , about the creta, thar and fortuner in the post above :

- They've un-invented the purpose of a rubber tyre ; might as well have bullock cart wheels from the 18th century

[humyum]

Voted for tall tyres and regular wheels.

When I had got white alloys for my Swift Diesel 12 years back, I resisted the temptation and got 14 inchers instead of 15 or 16. The tyre size too was 185-70-R14 and still is the same on black steel rims.

We are a roadtrip family. We quickly decide on a place, star the car and scoot. I have taken the Swift to Leh as well as inside the core area of Gir which has no roads to some silky smooth highways of Rajasthan. For me this is my suv, this is my hatchback and this is my cross over. I know it could turn better with say a 60 profile and 195 or 205 width tyre, but with the power and handling of the Swift coupled with my ambition, adhesion has never been an issue with the softer Michelins.

Looks for me are less important than purpose

[Thad E Ginathom]

Originally Posted by S15

... And that Thar with 24 inchers.

Ridiculous. The "natural" OTT tyre upgrade for a tough vehicle would not be a skimpy thing with no room for air (taking the technology back centuries, as venkyhere rightly says) but something more like miniature tractor wheels.

[GTO]

Driving inside Lonavla, enjoying the lovely weather with the windows down and I hear a loud POP & HISS. Immediately knew its a tyre gone. The CBU S-Class comes with a horrid low profile tyre setup on 20 inch rims! Thankfully, the CKD will be coming with 18-inchers. When I was swapping the tyres, I noticed that the jack has been used on this brand new car. Clearly, someone else also faced the same problem. Imagine, this was within a nearby hill station on rough roads (not even a pothole). A car I'd love to go to Goa in, but sadly, these 20-inch wheel variants wouldn't be up to the task. Wait for the CKD with 18s, guys.

Even worse was driving all the back at 80 - 90 kmph! Because the S-Class has a staggered setup, you have 3 different tyre sizes when using the spare. Completely messes up any expectation of handling.

[jagzrk]

So, I am in a dilemma about upsizing tyres on XUV300 W8O which currently has 215/55 R17 on 6.5J alloys. Already have had an incident of tyre burst due to bad roads and absolutely not a fan of lower profiles tyres.

The 6.5J rim leaves absolutely no room for upsizing but anyway all I want to do is increase the sidewall height. The only possible size seems to be a downsize to 205/60 R17 with a 1.42% difference. The other option 215/60 R17 has a 3.22% difference.

Has anyone driven with such difference in tyre upsize? Do suspension systems and electronics get affected due to this change in circumference?

It seems both of these sizes vary the contact patch size significantly, one skewed in vertical direction and another horizontal. How much does this matter to the car suspension & electronics?