Tyre Size Comparison: 175/65R14 and 175/70R14

[amsandun]

Hi all, I know there's more than enough websites on above topic and detailed information. Still I got somethings to get clarified. 

I am to change all tyres in my Vitz as they have done 58000+ and looks so bad at the moment (2 of them are worse). Stock tyres are 165/70R14 and the stock wheel was 5Jx14 ET39. I put alloys of 6 inch width (as I remember). Now I want to put 175mm width tyres this time. Recommended alternative tyre by almost all tyre size comparison websites is 175/65-14 where the sidewall height will be reduced by nearly 2mm. (so correct me if I am wrong: overall height (clearance) is reduced by ~4mm?) 

Due to this reason many tyre shops recommend to put 175/70-14 instead saying when there's a load, it might hit the ground at some points.

Please comment your ideas and knowledge in this matter please.

this is the screenshot of the famous tyre size comparison website where it doesn't show the difference of sidewall height. (All other websites shows there is a difference)

 

[iRage]

Yes...your vehicle height will slightly reduce. Most of the time for most people this goes unnoticed as they move on to larger sized rims along with their low profile tires. 

Along with the width, your speedometer will alos be slightly off. Your tire essentially has to rotate a little bit more to achive X distance so as a result you technically shoulod lose a bit of fuel efficiency. To be honest the last tow changes are probably going ot be negligible since it is a very small change.  The lower profile means your turning will feel more crisper (as there is lesser squigy side roll from the tore's body) but you also will feel tht the ride is a bit harsher than before (less of a buffer area on the tire).

[amsandun]

On 11/15/2021 at 6:24 AM, iRage said:

Yes...your vehicle height will slightly reduce. Most of the time for most people this goes unnoticed as they move on to larger sized rims along with their low profile tires. 

Along with the width, your speedometer will alos be slightly off. Your tire essentially has to rotate a little bit more to achive X distance so as a result you technically shoulod lose a bit of fuel efficiency. To be honest the last tow changes are probably going ot be negligible since it is a very small change.  The lower profile means your turning will feel more crisper (as there is lesser squigy side roll from the tore's body) but you also will feel tht the ride is a bit harsher than before (less of a buffer area on the tire).

Thanks for the comment brother. Decided to go with 175/70R14 after considering all the facts. Got 4 Hankook Kinergy Eco2 tyres today. Gong to get them fitted within next 2,3 days after after the 5000km service.  

[Izza]

@amsandun How is your experience after upgrading to 175? Thinking of doing the same for a Vitz 1.0L myself.

[tiv]

My wife's Vitz has 195 50 R15 7JJ, I think it's ET35

2018 1L engine, there's no difference in fuel economy, or the measly pull, There's no rub either.

The car came with puny 14s

It's got heaps more grip, and is very comfortable. 

Running Nexens  

I don't understand the paranoia here, if a friend has a starlet gt around, do a test fit and see. It's a common size in the starlet gt fandom.

There are cars running 16s and 17s also In SL with 50 and 45 profiles 

Edited December 29, 2021 by tiv

[Izza]

1 hour ago, tiv said:

My wife's Vitz has 195 50 R15 7JJ, I think it's ET35

2018 1L engine, there's no difference in fuel economy, or the measly pull, There's no rub either.

The car came with puny 14s

It's got heaps more grip, and is very comfortable. 

Running Nexens 

Wow, no fuel economy & pulling power change after going for 7JJ with 195 tires? Bdw, just for my knowledge what is the average fuel econ figure you see?

 

1 hour ago, tiv said:

I don't understand the paranoia here, if a friend has a starlet gt around, do a test fit and see. It's a common size in the starlet gt fandom.

There are cars running 16s and 17s also In SL with 50 and 45 profiles 

Well I think before doing a mod its better to know the consequences. And yes, I too am thinking for fitting a used set of tires to get an idea first 👍

[tiv]

4 hours ago, Izza said:

Wow, no fuel economy & pulling power change after going for 7JJ with 195 tires? Bdw, just for my knowledge what is the average fuel econ figure you see?

 

Well I think before doing a mod its better to know the consequences. And yes, I too am thinking for fitting a used set of tires to get an idea first 👍

Car does about 12kmpl in Kandy roads and traffic, its hilly here and she drives slow so it's kinda the same before and after, also the wheels were swapped in early 2020, so no suspension issues either

[amsandun]

On 12/27/2021 at 9:38 AM, Izza said:

@amsandun How is your experience after upgrading to 175? Thinking of doing the same for a Vitz 1.0L myself.

Hi, in short, there's nothing to complain about. Plus, the car looks better too. No noticeable low fuel performance either except drains the wallet more due to increase in petrol price 😄. Feels like I got more grip.

One other thing, I hear uncomfortable road noise only when driving on the highway. On the normal roads there's not. Not sure it maybe the car, tire or the road. But when I exceed 100 km/h on highway for a bit, that noise goes away.

[Izza]

9 hours ago, amsandun said:

Hi, in short, there's nothing to complain about. Plus, the car looks better too. No noticeable low fuel performance either except drains the wallet more due to increase in petrol price 😄. Feels like I got more grip.

Nice!
Lol same concern here mate. Thankfully the Vitz is happy with 92 octane.

9 hours ago, amsandun said:

One other thing, I hear uncomfortable road noise only when driving on the highway. On the normal roads there's not. Not sure it maybe the car, tire or the road. But when I exceed 100 km/h on highway for a bit, that noise goes away.

Is it in the same stretch of highway you get this noise? I experienced a similar noise from tires few times in the highway (in a different vehicle though). Checked the tires and then noticed that in the particular stretch of highway, the carpeting has been removed and roughened for re-carpeting, hence the noise. The noise went away once the re-carpeting was done.

[amsandun]

6 hours ago, Izza said:

Thankfully the Vitz is happy with 92 octane.

ha ha  of course

[amsandun]

8 hours ago, Izza said:

Is it in the same stretch of highway you get this noise? I experienced a similar noise from tires few times in the highway (in a different vehicle though). Checked the tires and then noticed that in the particular stretch of highway, the carpeting has been removed and roughened for re-carpeting, hence the noise. The noise went away once the re-carpeting was done.

I can't say for sure, almost all along the Katunayake Highway. It's not because of the 175 tyre, that I can say.