The Finished product
Before jumping to a bit more story and the thought process, here's how it all ended.
 |  |
Choosing the right tyre
It was not very tough to decide the brand of the tyre. Google listed www.team-bhp.com forums, and there were plenty of posts on it. Unanimous choice was Michelin for the driving comfort, though there were some cons that it is not 100% made for bad indian roads. Hey but we have lot of 4-laned tolled roads now, and as most of the fuel would be burnt there, I decided to go in for Michelin straightaway.
I had to do a thorough research to find the right upsize for my i10. Courtesy lots of Tyre size calculators online, I was able to list down these options:
Original Tyre Size
| Tyre code | Diameter | Circumference | Difference |
|---|---|---|---|
| 155/80 R13 | 578 mm | 1816 mm | 0 % |
Upsize Options
| Tyre code | Diameter | Circumference | Difference |
|---|---|---|---|
| 175/65 R13 | 558 mm | 1753 mm | -3.55 % |
| 185/65 R13 | 571 mm | 1794 mm | -1.3 % |
| 165/70 R13 | 561 mm | 1762 mm | -2.94 % |
| 175/70 R13 | 575 mm | 1806 mm | -0.52 % |
| 185/70 R13 | 589 mm | 1850 mm | 1.9 % |
| 155/75 R13 | 563 mm | 1769 mm | -2.68 % |
| 165/75 R13 | 578 mm | 1816 mm | -0.09 % |
| 175/75 R13 | 593 mm | 1863 mm | 2.51 % |
| 155/80 R13 | 578 mm | 1816 mm | 0 % |
| 165/80 R13 | 594 mm | 1866 mm | 2.77 % |
| 175/60 R14 | 566 mm | 1778 mm | -2.18 % |
| 185/60 R14 | 578 mm | 1816 mm | -0.1 % |
| 155/65 R14 | 557 mm | 1750 mm | -3.65 % |
| 165/65 R14 | 570 mm | 1791 mm | -1.4 % |
| 175/65 R14 | 583 mm | 1832 mm | 0.85 % |
| 185/65 R14 | 596 mm | 1872 mm | 3.1 % |
| 155/70 R14 | 573 mm | 1800 mm | -0.97 % |
| 165/70 R14 | 587 mm | 1844 mm | 1.45 % |
| 175/70 R14 | 601 mm | 1888 mm | 3.87 % |
| 155/75 R14 | 588 mm | 1847 mm | 1.71 % |
RIM Size & Width
I had a tough time to decide whether to go for a R13 or R14 dia Rim. R14 would decrease the profile, making the ride bit rough. If I had maintained the profile, then I had to endure few scratches on the body when riding on speed humps. Greater RIM Dia would increase the visual appearance, but that could lead to a not so good ride quality. Hence, I decided to go with R13 Rims only.
Then, I had to choose the RIM Width that is appropriate for the new tyre's width. I've covered those in detail in the upcoming sections.
Deciding on Tyre Size
I had to choose a tyre size such that the overall difference in circumference should be less than +-2%. While increasing the diameter could have increased the profile for a comfortable ride quality on smooth roads, it would have scrapped few coatings from the wheel cavity, and damaged the front mud-flaps on sharp turns. Decreasing the diameter could have adverse effects on the ground clearance. Esp. on indian roads with sewage mini bridges, converted to massive speed humps, you need to maintain (as far as possible) the original ground clearance.
155 was ruled out, so I had to choose from 165 to 185. Ideally there was only a choice between 185 and 175, as 165 too seemed apparently small. The visual appeal from 175 was much more than 165, so the options were narrowed down to 175 or 185.
While 185 would give a better look, I know I have to compromise a bit more on mileage. Moreover, there was the concern of the tyre protruding out of the body awkwardly which could result in a mismatch in looks vs size. Moreover, there was a concern on team-bhp, that on few i10s, 185/60 R14 had touched the inner wheel cavity on bumpy roads. One of my friend had 185/60 R13 on his i10, sporting the Yokohama A-Drives that looked classy. But, I figured out that it has decreased the circumference by -81.68mm that is -4.5% difference. But, he seems to be pretty happy with his tyres and ground clearance. I still was not able to make the choice between 185 & 175. Unfortunately or I would say fortunately (as it narrowed down the options available) Michelin did not have 180/70 R13, so I decided on 175/70 R13 finally.
I also found out that the 175/70 R13 tyre had a speed rating of H (i.e. upto 210 kmph). With the realization that I could experience more stability on highways, I knew I am making a wise decision.
Choosing Alloys over Stock Rims
Another choice to make, was whether to mount the tyre on the stock rim or whether to go for alloys. Remember that if you increase the width of your tyre, you need wider Rims to accomodate them, else you would experience the sidewall strain, that can cause a cushioned ride and shorter tyre life. The recommended RIM Width for 175" wide tyres are 5J to 6J. So, 5.5 would be the ideal width. This was one of the most important factors to opt for alloy wheels during tyre upsizes.
So, having convinced myself that it makes sense to spend extra bucks to get a rich look, I decided to go for new alloy rims that could get me a wider Rims (good enough to mount 175 or even 185) and having more stable ride quality and increased tyre life.
I had a red-lip design in mind, to go with the body colour of my i10, but at the same time had other factors to consider such as strength of the casting, width of the spokes, number of spokes, etc. It was a contentious decision to opt for more spoke width, than the visually appealing red-lip design. So, I chose this design, that I would call "The violent Sudarshan Chakra", for it looks gorgeously violent !!!
I also had to go for a change in bolts to new chrome bolts, as it would match with the alloy looks, and provides better safety for tyres, in case, I had to park my car at a public garage for a longer period. The new chrome bolts come with a unique lock key, that would fit with the stock toolkit to fasten or unfasten.
The Numbers
New Tyre Size: 175/70 R13 (Stock: 155/80 R13)
Brand: Michelin (Stock: Bridgestone)
Speed Rating: H (Stock: S)
Alloy Wheel: CP Wheels
Rim Width: 5.5J (Stock: 4.5J)
Cost: Ask me!
Links to Tyre size calculators
http://www.alloywheels.com/tyrecalc.asp
http://www.miata.net/garage/tirecalcold.html
http://www.tyrestore.in/upsizing.htm
Links to Alloy Wheel manufacturers Web-site
http://www.auraalloywheels.com/
http://www.alloywheels.in/
http://www.evoalloywheels.com/index.html
http://www.acealloywheel.com/
http://www.alloywheelsindia.com/
http://www.apollotyres.com/acelerewheelz/index.htm
http://platiindia.com/aboutus.php5
http://www.neowheels.com/
http://www.mahalaxmiauto.com/products/index/alloy-wheels_413.html
http://www.aez-wheels.com/257_EN
http://www.lensowheel.com/
http://www.lexani.com/
http://www.limitedalloy.com/
http://photoshop-car-mods.blogspot.com/2009/05/add-alloy-wheels-in-photoshop.html
http://alloywheelsdirect.wolfrace.com/
http://www.speedywheels.com/
http://www.bestalloywheelsandtyres.com/alloy-wheels-and-tyre-packages/
http://www.skyalloywheels.com/
http://www.poweralloywheel.com/
http://chinesealloywheels.cn/?page_id=4&category=3
Michelin Logo
 |  |
OEM Michelin Tyre Pics
 |  |  |
Some Alloy wheels designs that I considered
 |  |  |
Pics Shot during Fitting
 |  |
