[trrk]

Hi Alfa_Kilo,

> a narrower replacement could be seriously dangerous.

I would agree with you that it could be dangerous.

> If you want a higher profile tyre for the sake of ride, then you may go in for 13 > inch rims and 175/75 tyres.

That would entail changing the rims also!

[trrk]

Hi,

> What tyre pressure are you running ?

I am following the manual in that.

> If the ride is too jumpy, try going down 1-2 PSI and see if its any better.

I would try that.

[trrk]

Hi Busa,

> The right downsize will be 175/70/14 and not 165/80/14

Did you mean 175/70R13? I know that 165/80R14 is not a correct downsize.

> Also if your getting better FE, that can be attributed to the speedo error.

As I could do testing on the City only for a measly 60 kms, I could not try much for fuel efficiency. I had to put them on the Marina as it needed new front tyres for a trip and they are on it now.

The fuel efficiency if checked without adjusting for the speedo error would actually suffer.

[trrk]

Hi Prajesh,

> U can get 185/65-14 if your main objective is to improve the ride quality.

OK. But I definitely did not want to increase the width on my CVT as it couold affect mileage.

For the present, I am not changing the tyres of my CVT. The narrower tyres are on my Marina.

How I wish the PCDs of Marina and City were the same! Swapping and testing would have been easy.

[rks]

Originally Posted by trrk

Right now they are doing duty in my Marina. It had a long distance run with my driver and he did not find anything amiss. Yesterday I did use it for 60 kms on a route that I take regularly take. Even in the Marina, it does make a difference the way the front tyres react to the road surface. I did try an emergency braking at 60kph and the car tracked true and the braking was as efficient as with the original spec tyres. Wet conditions are yet to be faced. These are going to be the Marina's front tyres as it needed new tyres anyway.

So you are using different size tyres in the front and rear of the Marina? I dont think that is advisable either. Especially since your downsize is apparently not the correct one, and so your rear tyres will now have different rolling radius (or OD) and ground clearance. I don't think that is good for the suspension or handling. Plus the wider (grippier) tyres in the rear could cause understeer in your car since the front tyres will not match the grip of the rear tyres as the tyres wear out. If want to downsize, you should do so for all tyres and not just the front ones. Anyway, keep a watch on the braking and handling as the tyres wear out and in wet conditions.

The load rating should be fine as these are the OEM tyres for the Swift. Ride does improve.

Isn't the Marina is a heavier car than the Swift?. The question is what is the load rating of the stock tyres on the Marina. As per most tyre sites, the load rating of upsized/downsized tyres should at least be the same as that on the stock tyres supplied by the manufacturer. When you go for a tyre upsize, this is usually not a concern as wider tyres will normally have a higher load rating. But when your tyres are downsized, you need to make sure that the load rating of the downsized tyres does not come down to below acceptable levels (maybe a slight decrease below that of the stock tyres would be OK, I am not too sure of this).

What would be the maximum width of alloy wheels that I can go for with the 168/80R14 tyres.

I think you mean 165/80 R14. For Indigo Marina my understanding is that the stock size wheels are 5J X 14". For 165/80 R14, you could go up to 5.5J. Higher than that is not advisable under Indian road conditions. With wider rims the braking/handling will improve, and ride quality may come down marginally. I am having 5J alloys on 155/70 R13 tyres, which is the maximum allowed width for that size.

[trrk]

Hi rks,

> If want to downsize, you should do so for all tyres and not just the front
> ones. Anyway, keep a watch on the braking and handling as the tyres wear > out and in wet conditions.

Usually I don't do such things. But I bought those tyres to test them and if I don't use them they will be a waste. I will keep a watch on the above things.

> The question is what is the load rating of the stock tyres on the Marina. As > per most tyre sites, the load rating of upsized/downsized tyres should at
> least be the same as that on the stock tyres supplied by the manufacturer.

I will check the load rating. The Marina is about 100kgs heavier.

> I think you mean 165/80 R14. For Indigo Marina my understanding is that
> the stock size wheels are 5J X 14". For 165/80 R14, you could go up to
> 5.5J.

Yes, I meant 165/80R14. The Marina alloy rims are also 5". The City has a 6" wide alloy.

[trrk]

Hi rks,

> Isn't the Marina is a heavier car than the Swift?. The question is what is
> the load rating of the stock tyres on the Marina. As per most tyre sites, the
> load rating of upsized/downsized tyres should at least be the same as that
> on the stock tyres supplied by the manufacturer.

CVT and the Marina both have 175/65R14 tyres.

The CVT came with Bridgestone S322 tyres. The load rating is 475kgs @ 44psi. The Marina came with Bridgestone styres (must be the same ones), but were changed at the showroom itself to Apollo Aceleres (never saw the originals) which are rated at 475 kgs @ 35 psi.

The 165/80R14 JK Toronadoes are rated at 515kgs @ 35psi.

So load rating wise, the narrower tyres are Ok, I guess.

[trrk]

Hi,

After all that talk about downsizing, I forgot to add an image.

Here it is:



They are doing great so far and have covered over 3500kms.

My photographic skills are very poor and this is from my Nokia 6265.

[kpzen]

I wonder how much the torque characteristics must have changed.
If u can then please do drive another Marina with stock wheels and let us know.

[trrk]

Hi Prajesh,

>I wonder how much the torque characteristics must have changed.

You did mention that when we met in Kalpakavadi. I could not make out much of a difference in the Marina. The surge when it crosses the 1900-2000 mark is still apparent. Mileage has been also consistent.

But I did notice a change when I tried it in the front wheels of the CVT. With stock wheels if you take the foot off the accelerator, there is a small jerk when it shifts to lower gearing. This jerk was not there with the 165/80R14 tyres, the reduction of the gearing was jerk free. Acceleration etc were no different as far as I could see. Since the test was only for 60kms, I was not able to make out any apparent change in mileage.

> If u can then please do drive another Marina with stock wheels and let us
> know.

Except for shop and house I hardly step out in Alleppey. So I am not aware of much people and driving a Marina with stock wheels has to be at a dealer.

If I get a chance, I would do that.

[anarchy_99]

correct me if i am wrong...
but since in 205/50/R15 etc 50 denotes the ratio of the sidewall height to the width, therefore reducing the tire width and increasing the ratio, will not actually increase the sidewall hight, especially since the rim size remains the same and overall diameter must remain practically the same.

[trrk]

Hi folks,

A little belated update!

By the first week of August 2008, my Undersized marina completed its 10000kms without any problems.

In this eight months, it has had its share of time in different seasons and different roads. The only thing it did not have a chance is to go on a hill section other than the famous 'Kuthiran'!

It has performed well. There are no handling issues and braking has been faiult free from speeds upto 100kph.

I will have to wait for atleast another 25000 kms for the rear tyres to be worn enough to change them. Well one of them is only 33000kms old where as the other has run all the mileage until now. So the one which has run more now may force me to a tyre purchase earlier than I would have to.

With the usual JK toughness, I expect these tyres to last me more than the 35000kms the Apollo Aceleres gave me in the front axle.

[drsingh]

I'm currently driving a Fiat Linea emotion with ridiculous 225 /60/15 wheels.

Now I plan to change them and go for the suspension upgrade from the ASS.

From a better ride perspective would it be better to get 14 inch wheels /alloys and put 185/70/14 Tyres on them, or 195 section on 14 inch wheels?


Any idea about the reduction in unsprung weight when going from 15 to 14 inch wheels?

[sagarpadaki]

Originally Posted by drsingh

I'm currently driving a Fiat Linea emotion with ridiculous 225 /60/15 wheels.

Now I plan to change them and go for the suspension upgrade from the ASS.

From a better ride perspective would it be better to get 14 inch wheels /alloys and put 185/70/14 Tyres on them, or 195 section on 14 inch wheels?


Any idea about the reduction in unsprung weight when going from 15 to 14 inch wheels?

Why did you upgrade to such a wrong upsize?!

Change back to the stock spec that the current linea top end trim comes in. You will be happy with the ride. Don't change to 14 inch rims as handling will be compromised

[drsingh]

Originally Posted by sagarpadaki

Why did you upgrade to such a wrong upsize?!

Change back to the stock spec that the current linea top end trim comes in. You will be happy with the ride. Don't change to 14 inch rims as handling will be compromised

I just bought the car used ☺. This is in punjab- the land of ridiculous tyres. 14 inch wheels give me the ability to go for a wider sidewall. Hence my question.

what about reduction in unsprung weight? I will be keeping the 195 section just like the stock tyres. Just want to increase the sidewall width.

Can you explain this in some detail?