I bought a set of 4 for my Ritz. Size : 165/80/R14. Here is my feedback after driving 1200 km over all type of roads/terrains

Pros (all compared to OEM JK):
1. Silent over highway speeds
2. Comfort ..Ride is smoother
3. Got the free track suite.
4. Marginal increase (may be just a feel) of height
5. Looks on the car

Cons:
1. Very bad performance on Concrete roads. The ghat section near Kollur temple towards Shimoga has around 10+ km as concrete roads and vehicle was under steering a lot. Lot of squealing noises. Tyre was very hot after the descent; all indicating a poor grip of the concrete surface.

2. No (claimed) mileage increase, but probably a bit lower.

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I just updated my stock Etios VD tyres (at 61000 km) to a new set to Yokohama earth-1 series for 5100 per tyre with spec 185/65R15 as recommended by local tyre store (checkpoint, Bodakdev, Ahmedabad). The OE fitment tyre were of spec 185/60R15 so the aspect ratio is now higher. From ride perspective based on initial drives in city, the steering has become lighter which maybe due to new set of tyres. Earlier I used to feel harsh ride which now has soften a bit and also become more silent. However due to the higher aspect ratio, there is a bit of lateral movement noticed when doing a quick turn to either side. Hope the highway behavior is not too much affected.

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It's interesting that you find the steering to be lighter after having oversized the tyres. Are you sure you're running the right pressure. In fact, the pressure may not be the same for oversized tyres unless they have the same weight rating!

I checked with the tyre shop and they asked me to put in the same air pressure of 32psi as it was with stock tyre. Also I have noticed the ride is now getting better with less lateral movement during quick steering. I had a long highway trip and I can say the road grip is good and even during hard brake the car does not skid or let the ABS kick in early. So overall I am happy with the purchase even though I would stick to stock ratings next time.

Installing tyres with diameter larger than your (OE) tyres you will also get incorrect speed reading. In this case your tyre upsize will show 3% less speed than actual eg. You will see 100km/hr on speedometer however your actual speed will be 103km/hr at 120km/hr actual 124km/hr and at 140km/hr actual 145km/hr - I know in India speed limit is not strictly followed nor fines levied however its always good to know that you are faster than what your speedometer tells you

I also find my steering to be way harder compared to stock tire even though i didnt upsize and keeping the same pressure. I took car to the tire dealer and they plainly washed their hand saying its a car issue (even though they made a claim of lighter steering before sale).

I took 2 long drives of 1200 km each within 6 weeks of tire upgrade, the harder steering caused a shoulder pain for me in both the drives (which never occurred earlier in the same routes which I cover 6+ times in an year).

I am kind of clueless on what to do now.

But I must appreciate, ride is much smoother and silent now.

automachine,
My recommendation would be to check the load ratings of the stock tyres and also the new tyres and calculate the required pressure.
Is an indicative calculation, most 185/60R15 tyres have a load rating of "84" whereas most 185/65R15 tyres have a load rating of "88".
These ratings of 84 & 88 translate to 500Kg & 560Kg Max Loads respectively.
Assuming that the max inflation pressures of both tyres is the same, the required pressure would be:

Toyota Recommended Pressure x 500 / 560

So if Toyota recommends 32 PSI for the Original tyre, accommodating for the slightly increased sidewall, you should run 29 PSI on the new 185/65R15 tyres. (32x500/560 = ~28.6PSI).

I would also encourage you to please read the post linked below:
Calculating Required Tyre Pressure

IPathan,
In reality, the speedo is normally more accurate with the larger tyre than with the stock tyre. All car manufacturers are legally required to ensure that the speedo does not under-report the speed (vehicle traveling faster than shown by the speedo). Due to this EVERY car is set to ALWAYS OVER-REPORT the speed. Although not with lab level accuracy, this is very easily tested with a smartphone that has a GPS based Speed App.
With own verification, I can confirm that the Skoda Superb & Skoda Octavia Over-Report Speed somewhere between 4-5%, a Toyota Innova by just over 4%, a BMW 5 Series by a little over 2% and a Hyundai Elantra by about 7% (yes, seven %). I have found the Mercedes to be the most accurate of the lot at just UNDER 2%.
In fact, the calibration is normally such that the error is greater at low speeds and lesser at higher speeds (yes, I've triple checked what I've typed).
For example, my Skoda shod with 235/45R18 front tyres (~5.82% larger than the stock 205/55R16 size) under-reports the actual speed by about 0.5Km/h at a speed of 80 (i.e. show 80Km/h on the Speedo while actually going about 80.5Km/h based on a GPS reading), whereas at 200Km/h on the speedo the car is actually going ~203Km/h based on a GPS reading.

Check this out:
Skoda Superb with Larger Tyres

arjithin,
I'd have to agree with the tyre dealer here because there is really no reason for the same tyre size to affect the steering in a perceivable manner.
Do confirm if you have changed the wheels? I have seen people change to alloys with substantially different offsets to the original wheels which obviously causes a change in the track length and exponentially increases the load on the steering system.

No I haven't changed my wheels. I am on the stock rims.

Reading this explains why my alto showed 100km/hr while GPS showed 96km/hr on GPS, just to add to your list Elite i20 (Asta) and Verna (SX) shows +/- 1% speedometer Vs GPS. Hyundai Elantra 7% error is shocking :Shocked:

Smartphone with GPS based Speed App continuously locates your exact position and calculate how far you have travelled, then divide by the time it took for you to travel that distance, they are unable to take vertical movements into consideration, so may be less accurate if you are travelling up or down a steep hill - I always thought that was the reason of variance but now I have another impacting factor added to my knowledge base - Thanks

arjithin,
I am at a loss to explain this as I assume you have double checked the tyre pressures? Not after the car was driven but first thing in the morning when the tyres were cold? I have observed that tyres need a bit of 'recharge' during the winter as pressure drops as a function of temperature.
Else the only other possibility I can think of is a power steering or steering fluid issue.

IPathan,
I am referring to the old model Elantra which is now discontinued.

Try to get a GPS App that includes compass and altitude measurements (The logic of 'triangulation' that GPS systems are based on, provide for fairly accurate altitude measurements, without any need for an altimeter).
Albeit off topic, I use an app called "SpeedBox" by Hans Schneider that met all requirements. It displays GPS Accuracy, Current Speed (also in time lapse as a graph), Max Speed, Average Speed, Distance, Altitude, Direction, Does Data Logging at 1 second intervals (which can be exported to Excel), is capable of speaking the speed, provide speed warnings and even works in HUD mode so you can just put the phone face up on the dash!
Here is a screenshot (I have the altitude graph disabled):

@bharatsomany, many thanks on the detailed explanation. I tested with 30 psi and now the ride is much better and close to new oem tyres as I remember. Infact it is a bit better on rough surface as it absorbs the undulations and the steering feel on highway is better weighted than at 32 psi.

[quote=bharatsomany;3614494]automachine,
My recommendation would be to check the load ratings of the stock tyres and also the new tyres and calculate the required pressure.
Is an indicative calculation, most 185/60R15 tyres have a load rating of "84" whereas most 185/65R15 tyres have a load rating of "88".
These ratings of 84 & 88 translate to 500Kg & 560Kg Max Loads respectively.
Assuming that the max inflation pressures of both tyres is the same, the required pressure would be:

Toyota Recommended Pressure x 500 / 560

So if Toyota recommends 32 PSI for the Original tyre, accommodating for the slightly increased sidewall, you should run 29 PSI on the new 185/65R15 tyres. (32x500/560 = ~28.6PSI).

I would also encourage you to please read the post linked below:
Calculating Required Tyre Pressure

Bharat ---- The steering gets tighter when you increase the width of the tyres. Not when you only increase the height.

Secondly, even after going for wider tyres, the steering can become lighter. Why? Because the new tyre's rubber may be softer. Which means less friction with the road i.e less effort required to turn the steering wheel.

Sorry, the steering effort required in case of a taller tyre would also be more.
And if newer tyres would have lesser coefficient of friction,the tyre would even grip lesser but that's not the case?

I did check with few auto experts and they mentioned that as the tyres are new the tyre surface contact with road is less due to curvature of tyre and after later it would become better.