Team-BHP - disproportionate Tyres?

Hi,
I would be buying the swift vxi and am thinking of going for a tyre upgrade. I may do this immediately if I get a good offer on the new stock tyres or would do it a little later after saving up some dough. In any case, I have this idea in mind and I would like to get the opinions of tyre gurus about this.

What I would like to do, is that I wish to go for two different sizes for the front and the rear, like in the muscle cars of yore. I would like to keep the front rims at 14" and might even leave the standard tyres on. But at the back, I would like to go for wider tyres, on at least a 15" rim. How does this sound? So that would make a 165/80 14" or 185/70 14"(better) on the front and maybe a 215/55 15" or wider at the rear.

I know this would lead to (definitely) problem such as, what to do in case of a puncture (other than carry 2 sets of spares), but would it cause issues with braking and stability and any other thing critical? Also, has any such thing been done before on any Indian car, and if yes, then what is your opinion on such a mod?

Thanks,
kuku

Quote:

Originally Posted by herculesksp (Post 341483)

What I would like to do, is that I wish to go for two different sizes for the front and the rear, like in the muscle cars of yore. I would like to keep the front rims at 14" and might even leave the standard tyres on. But at the back, I would like to go for wider tyres, on at least a 15" rim. How does this sound? So that would make a 165/80 14" or 185/70 14"(better) on the front and maybe a 215/55 15" or wider at the rear.

No no no you can't do that. The reason those old muscle cars had wider tyres at the back was because they were Rear-Wheel Drive (RWD) and they needed the extra grip at the back with the monstrous outputs those huge V8's used to put out. Your Swift is Front-Wheel Drive & puts out a measly 87 bhp so you certainly don't need the sizes you mentioned.

Also by putting wider tyres at any one end of the car you are creating a situation where one end of the car has more grip than the other & in fast turns, curves etc, this can lead to bad consequences. For example if you mount wider tyres on the front wheels & thinner at the back then in a fast corner the rear could lose grip and result in unintentional oversteer! Which is not easy to control I might add & might result in a crash/injury etc.

Also there would be problems in case of a puncture etc. which you have already mentioned. Braking can also get effected with the car not stopping in a straight line due to the car being tuned for equal size tyres all around & you would be disturbing that by introducing more grip at one end & less at the other.

In FWD vehicles it is best to mount all four tyres of the same size. This coupled with the fact that our cars are not very powerful meets the requirements perfectly.

Recommended upsizes for the Swift are in the 14" & 15" sizes but if you want you can also go upto 17". AS for specific sizes & suggestions please use the search function as Swift tyre sizes have been suggested in many threads before.

Herculesksp,
It's not advised to install disproportionate tyres, the main reason is you would end up having 2 spare tyres. More over as Raghav suggested it's for power transfer the old muscle cars had disproportionate tyres and nothing more. You car would look lil slopy have to get your suspension modified all this at the cost of safety.
Speedometer,
You do get different J's with the same rim size and PCD. Check out the league and other Alloy websites for more information.
Thanks,
Mega