[cheap_deal]

it all depends on the right line into a corner and also the right line out of the corner. at a junction you wont be able to follow the racing line (if you do u will end up in oncoming traffic or the pan walla at the corner). best to goto a track and find out the limits of your car

[Shan2nu]

Turning speeds depend on a lot of factors. It's impossible for me to sit here and tell you what speeds you should be carrying into a corner.

You'l have to figure it out on your own. The fact that your car understeers, means that you're entering the corner way faster than what the tyres can handle. Slow down a bit on the entry.

The best way around a corner is when you have neutral steer.

Shan2nu

[rks]

@satishfaction, your posts set off warning bells in my head that you are heading for trouble. As Shan2nu pointed out, turning speeds depend on a lot of factors. Just because somebody took turns at 100+ kmph in a Matiz, don't assume that *you* can take *every* turn at 100 kmph in *your* Matiz. Always drive within your comfort zone -- with experience, you will become more comfortable taking corners as your driving skills improve and you get to know your car better.

Another thing that alarms me is that you say you have swapped your tyres from your 2001 Santro. This means that both the Santro (which you are selling off) and your Matiz have the wrong size tyres. Further, your tyres are already at least 5 years old. So it is time to change your tyres anyway. I also don't see how anyone in his right mind would even think of buying a Santro with 145/70 R 13 tyres. So I would say, swap back (if you haven't already sold off your Santro) and go for new tyres in your Matiz.

If your intention was to throw your car into corners, you should have thought about your tyre upsize more carefully. 155/70 R 13 is not the correct upsize for 145/70 R 13 -- especially considering that you do not have power steering. You should have gone for a lower profile (you can check the correct upsize at the carbibles website or elsewhere) -- this would have improved handling plus the lower weight of the tyres would have helped in steering. Secondly, you should have gone for tubeless tyres, assuming your stock rims are not too rusted or bent -- this makes a world of difference to your cornering, plus the lower weight due to lack of tubes would have helped with your steering. And alloys are recommended too, provided you choose them carefully to match the stock rim specifications -- the lighter alloys would also have helped improve your steering response.

I went from my stock tubed S322 tyres to the tubeless S322 of the same size (155/70 R 13) in my Santro on stock rims and found that I can take the corners at much higher speeds with no noise from the tyres. I didn't consider an upsize because the stock rims are 4J and you need at least 4.5J for the next upsize (165/65 R 13). The grip is vastly superior with the tubeless tyres, and really there is no need at all for an upsize in the Santro as far as grip is concerned. I would guess that the same holds of the Matiz as well. Your tyre pressures also matter. If you want to corner at high speeds, I would recommend that you set your tyre pressures 3-4 Psi above the manufacturer's recommendation -- this will help in cornering plus improve the life of the tyres.

[rahul_intlad]

@rks While upsizing the stock matiz tyres[145/70/R13] to the 155/65/R13 will there be a significant loss in ground clearance.

@shan2nu Thanks a lot reducing the tyre pressure seems to work,but will it affect the tyres.I will get the tie rod checked during my next service which is not very far away.

@kinetik Thanks

[Shan2nu]

@shan2nu Thanks a lot reducing the tyre pressure seems to work,but will it affect the tyres.I will get the tie rod checked during my next service which is not very far away.

Keep a close watch on tyre wear. If you see any unusual wear, increase the pressure. The fact that you car feels more composed with this setup shouldn't really affect the tyres.

Shan2nu

[rks]

@rahul_intlad, the sidewall heights are 145*0.7=101.5 mm and 155*0.65=100.75 mm. So the difference is less than an mm and should cause no problems. Whereas with 155/70, the sidewall height is 108.5 mm, an increase of 7 mm, which can only worsen the handling. It is always advisable to keep the ride height as close as possible to the manufacturer's value. Undoubtedly 155/65 R13 is the correct upsize, as per the carbibles website.

[rahul_intlad]

Makes me feel all the more stupid ,that I upsized without researching well.

@rks thanks will keep in mind in future.

@shan2nu thanks again

[satishfaction]

Originally Posted by Shan2nu

The fact that your car understeers, means that you're entering the corner way faster than what the tyres can handle. Shan2nu

Shan2nu, Thanks for the tip. After the first fiasco I have drastically reduced the speeds at which I take the turns.
The thing that I want to understand is how the same car with same tyres and at same speed perform differently at different gears? 60+ KPMH turn in 4th/5th gear the car looses control and at 70-80KMPH turn in 3rd gear the car is very composed. Is it only perception ?(I hope not as I have experienced this many times)

[satishfaction]

Originally Posted by rks

Further, your tyres are already at least 5 years old. So it is time to change your tyres anyway. I also don't see how anyone in his right mind would even think of buying a Santro with 145/70 R 13 tyres. So I would say, swap back (if you haven't already sold off your Santro) and go for new tyres in your Matiz.

RKS, This might be boring but a little background history is.. I had a 2001 Santro on which I have got 155/70/R13 fitted in 2005 (An year old till date and clocked 10000KM till now). These tyres were swapped to my Matiz and the Santro was sold off after understanding the buyer will get new set of shoes immediately for the Santro.
I understand after reading all the posts that 155/70/R13 is not the right upgrade but before doing that I checked some Indian car website (carindia or indiacar something like that) which quoted that this upsize is ok!
Since I already have these tyres, I have to live with them. Also, the problem that I am quoting is not a generic one and the car is very stable and smooth on straight lines and eats corners if driven into. It is an issue only when I push it around the corner, the stability goes for a toss.
IMHO, tyres could be one reason but suspension and gear/torque at the conrer might be important too. I would like to understand that side of the story.. Hope the post is not too long

[satishfaction]

Originally Posted by Shan2nu

Turning speeds depend on a lot of factors. It's impossible for me to sit here and tell you what speeds you should be carrying into a corner.
Shan2nu

Okie.. Let me put it this way.. There is a way to measure the quickness (0-60KPMH in X sec) and Fast'ness'(Top Speed X KMPH) but how to quantify the handling of the car?
PS: No offence meant to any one, I would like to have a car which would top may be 120KMPH only but can handle corners in a nice and composed manner. Hope I am not the only who has such strong focus on handling.

My Audio system (KENWOOD - KDC X889) can measure G-forces. Can this be of any use to measure the handling? (I might be sounding ignorant, but I need to know!)

[Shan2nu]

Shan2nu, Thanks for the tip. After the first fiasco I have drastically reduced the speeds at which I take the turns.
The thing that I want to understand is how the same car with same tyres and at same speed perform differently at different gears? 60+ KPMH turn in 4th/5th gear the car looses control and at 70-80KMPH turn in 3rd gear the car is very composed. Is it only perception ?(I hope not as I have experienced this many times)

Thats bcos as you shift down the gears, theres far more engine braking at a given speed. So, even though you're not using the brakes, the cars speed around the corner is governed by engine braking.

At 70kmph in 5th the engine would be revving at around 2000 rpm but in 2nd, the same engine would have to revv at 4000+ rpm.

This provides more torque at the wheel and the higher engine resistance sees to it that the car doesn't wander off it's intended line. All said and done, if you exceed the capabilities of the your cars traction, you'll still go off, no matter what gear you're in.

Okie.. Let me put it this way.. There is a way to measure the quickness (0-60KPMH in X sec) and Fast'ness'(Top Speed X KMPH) but how to quantify the handling of the car?
PS: No offence meant to any one, I would like to have a car which would top may be 120KMPH only but can handle corners in a nice and composed manner. Hope I am not the only who has such strong focus on handling.

My Audio system (KENWOOD - KDC X889) can measure G-forces. Can this be of any use to measure the handling? (I might be sounding ignorant, but I need to know!)

It's impossible to give a generalised estimate of what speed your car can carry around a corner.

Cornering Gs vary with traction,vehicle weight, suspension setup etc.

No tyre will give you the same traction throughout the day. Filling up your fuel tank increases the weight of your car. This too will affect cornering forces and handling characteristics.

No car in this world car maintain the same cornering capabilities over a peroid of a few 100 kms (not even an F1 car).

Ever wondered why qualifying lap times are better than race lap times? Thats bcos a qualifying car uses the least amount of fuel (to reduce weight) and makes the best of what traction is available.

Using a G meter will give you the G forces your car can handle at that point of time. You might do better or worse on a diff day and time.

Shan2nu

[rks]

Originally Posted by satishfaction

RKS, This might be boring but a little background history is.. I had a 2001 Santro on which I have got 155/70/R13 fitted in 2005 (An year old till date and clocked 10000KM till now). These tyres were swapped to my Matiz and the Santro was sold off after understanding the buyer will get new set of shoes immediately for the Santro.
I understand after reading all the posts that 155/70/R13 is not the right upgrade but before doing that I checked some Indian car website (carindia or indiacar something like that) which quoted that this upsize is ok!
Since I already have these tyres, I have to live with them.

All I can say here is that if I were a prospective buyer of your Santro, I wouldn't have agreed to the deal. Because there is no way for me to test-drive your car and come to any valid conclusion with 145/70 R13 tyres on it. The Santro will be a total disaster with these tyres. I would also be worried about how many kms you have driven the Santro with the under-sized tyres and what damage that may have caused. Anyway, as you say, the deal is done and you have to look ahead.

Also, the problem that I am quoting is not a generic one and the car is very stable and smooth on straight lines and eats corners if driven into. It is an issue only when I push it around the corner, the stability goes for a toss.
IMHO, tyres could be one reason but suspension and gear/torque at the conrer might be important too. I would like to understand that side of the story..

The tyres are a very important aspect if you want to do high-speed cornering. Why did you sell your Santro and go for a Matiz? The Santro is a newer generation car and its high-speed handling and cornering should definitely be superior. Have you never tried to push your Santro the way you are attempting with the Matiz?

[satishfaction]

Originally Posted by rks

Why did you sell your Santro and go for a Matiz? The Santro is a newer generation car and its high-speed handling and cornering should definitely be superior. Have you never tried to push your Santro the way you are attempting with the Matiz?

The reasoning is simple. I have both the cars since 2001. I needed money immediately and the decision was easy that I would fetch almost double if I sell Santro vis a vis Matiz. Also, Matiz was bought brand new at almost 4.5lakhs and did only 30000 till date. Where as Santro was bought in second hand in 2001 and now I got half of it on third sale. Also, it did 60000KMS till date.
Matiz is intended to be the second car till the time we buy our first car (Given the low mileage and very good engine). It is not meant to be driven for performance. Sadly, till the time, I get another car for my self, Matiz is facing the music!
I tried doing similar things with Santro too, and it was ok though couple of times on tight corners the outer wheels on the corner (left/right) used to go in air couple of inches.

[Su-47]

No offence meant to either of you, but I cant help but say:

satishfaction: Take it a little easy man! Please take incremental steps before you try WRC stuff on roads. Don't hurt yourself or someone else.

rks: Are speeds of 160 on a Santro routine stuff for you? Sounds insane! Please be careful, and if possible please try to bring it down.

Drive safe!
Su-47

[satishfaction]

Originally Posted by Su-47

satishfaction: Take it a little easy man! Please take incremental steps before you try WRC stuff on roads. Don't hurt yourself or someone else.
Su-47

None taken buddy! Hope your Matiz is rocking after your new set of shoes!! I will keep your tip on mind while driving..