Ground Clearance

[naj]

Kpzen Sir,
Good day to you.
Thank you for explaining the tyre terminology with calculations.All doubts cleared.

Also can you please tell me by how much one can increase the rim size say from 13 inch to 14 to 15 taking into account that the tyres wont touch the wheel arches ?How to decide on that and gain max ground clearance for a given car.

Naj

[tsk1979]

Naj, this link has a handy calculator.
You can also use the article in advice section
Car Bibles : The Wheel and Tyre Bible Page 1 of 2

[sushrutha]

Stock Tire - 175/70R13 -------------Tire 1 - 175/65R14
Section Width: 6.88 in 175 mm ----Section Width: 6.88 in 175 mm

Rim Diameter: 13 in 330.2 mm ----Rim Diameter: 14 in 355.6 mm

Rim Width Range: 4.5 - 6 in ----Rim Width Range: 4.5 - 6 in

Overall Diameter: 22.64 in 575.05 mm ----Overall Diameter: 22.95 in 582.93 mm

Sidewall Height: 4.82 in 122.42 mm ----Sidewall Height: 4.47 in 113.53 mm

Radius: 11.32 in 287.52 mm ----Radius: 11.47 in 291.33 mm

Circumference: 71.12 in 1806.4 mm ----Circumference: 72.09 in 1831.0 mm

Revs per Mile: 918.7 ----Revs per Mile: 906.3

Actual Speed: 60 mph 100 km/h ----Speedometer1: 59.1 mph 98.6 km/h

Speedometer Difference: - Speedometer Difference: 1.368% too slow
Diameter Difference: - Diameter Difference: 1.36%
courtesy
Tire Size Calculator - tire & wheel plus sizing

[dharmana]

I got a Maruti SX4 Zxi recently. I don't like the high ground clearance(ride height) and want to lower the suspension a little bit(around 15mm) to make the car look more aggressive and sporty. I want to know if lowering kits are available in India or if not where do I need to go to get it done. Something like shorter suspension springs etc would be fine. I know I can decrease the ground clearance a bit by using low profile tyres but I want to lower the ride height by reducing the wheel well height. I would like to know if any sport suspension kits like lowering springs and matching shock absorbers are available in India and also if they are specific to the car model you own. Any names of reputed brands available in India would be a help.
For example the SX4 Sedan which was launched in America uses sport suspensions to bring the ride height down by around 10mm compared to the SX4 crossover which sits a little higher than the sedan. Any decrease in ground clearance of 10-25mm would be commendable as I might further lower the car in the future by going for lower profile tyres. Also does anyone know if this is a simple job which can be done in any automotive garage shop or if this is a complicated process and is done in only big cities like Bangalore, Chennai etc?

[itwasntme]

Check with BHPian Turboindia (Peter) or at Pete's Automotive Products Pvt Limited

He maybe able to help.

[Ram]

Suspension lowering is merely an word-of-mouth term for it, dharmana!

It is no doubt a complicated process. And it comes with a high probability of writing-off the design and relegating a worthy car to the wild and wacky thread!

Granted there are east Los Angeles low-rider clubs that tinker with this sort of thing, but bear in mind ...

...that they use bolt-on, factory-made, after-market components that have gone through rigorous engineering design by real automobile/aircraft designers.
Often, these are designed to exceed the specifications of the OEM components they are substituting.

And the base platforms modded by these clubs are strong X-frame 1963-67 rear-wheel-drive Chevrolet Impalas -- not bottom of the food-chain Japanese econoboxes, which were never purposed for longevity, anyway!

In the process details are:
Detailed study of the engineering drawings -- the tolerances -- suspension travel -- danger of bottoming out -- fabrication of custom suspension components -- guarantees, to handle the stresses you will put on the crate -- okaying by regulatory bodies ...

A very good strategy for you could be to import the lowering kit meant for the Suzuki SX4 sedan (USA or Canadian version).

You have to work with a qualified professional (let's call him an automotive architect) who designs cars for a living. Very few such people are found in India, to the best of my knowledge and will be fairly expensive.

They will have access to a great deal of expensive equipment, and a very well equipped factory with static and dynamic measurement instruments.

Your expenses can end up, somewhat more than simply importing a readymade production-line Corvette or Porsche or Italian sports job, for instance.

Beware of desi cosmetic modifiers (so called screwdriver street mechanics) who can't even take accurate measurements, nor make drawings worthy of marks in a qualified professor's scrutiny, leave alone handle automotive design software. They are invariably mentally-challenged as far as appreciating the safety and handling consequences of their tinkering.

Bear in mind that the final outcome may not pass professional inspection.

It's the difference between going to a super-specialty cardiac surgeon and going to a beachside masseur or witch-doctor, for crying out loud.

Ram