Tire Size And Ground Clearance

Rider · April 27, 2015

Car model: JDM Toyota Corolla 121 2005

Tire that were installed when I'm purchasing the car was 175/70R14 . Now the car tires need replacing, and I need some advice getting a new tire set.

As for the tire information (If I read this info correctly, which I'm not sure) this indicates two main tire sizes which are 175/70R14 and 185/70R14.

I always had the problem with ground clearance with this car, I'm hoping get 185/70R14 tire set that some what increase the ground clearance.

I need advice/ clarification before purchasing this tire set. Will this tire fit to my current rim set ?

If it does, Will changing result these scenarios?

ODO meter reading
Tire rubbing

What do you guys think?

Edited April 27, 2015 by Rider

nsiva · April 27, 2015

I am not sure about Toyota 121. But these two sizes mean for front & rear tyres separately? Because, these two tyre sizes have s height difference of 0.7cm from the centre axis. Usually, manufacturers give a tyre combination with different wheel + tyre combination which result in equal whole tyre diameter. Not differing diameters.

185x70 = 185mm x 70% = tyre height (balloon size)

Rider · April 27, 2015

hmmm.. why did you come to suspect that two sizes for front & rear? couldn't if be choice of either this or that (185/175) for all four?

Edited April 27, 2015 by Rider

bycap · April 27, 2015

Following calculator shows the comparison.

https://www.tacomaworld.com/tirecalc?tires=175-70r14-185-70r14

Since you increase width of the tire only by 1cm, I don't think there will be any rubbing issue. But there is a slight change in speed and the odo.

luckey007 · April 28, 2015

Translated your sticker text using Google translator.

Says... Tire pressure[....], Tire size front and rear wheel ................... Emergency tires...............

I did not put numbers.

So according to the sticker, you can use both tire sizes. But larger size may be for alloy wheels which is wider. Then the diameter will be almost the same. When we see most of the models different tires are for different rims. Better to look in the catalogue.

Davy · April 28, 2015

70R means that the height of your sidewall is 70% of the width of your tyre. So, by going for 185/70R14, your sidewall height will change by about 5% and it will result in a slight speed 'o meter (and thereby the ODO as well) change.

1. Refer to this link to get a good idea about what kind of a change you'll be looking at:
https://www.tacomaworld.com/tirecalc?tires=175-70r14-185-70r14

2. Your tyres will not touch the wheel well because of a 7mm change.

EDIT: Nevermind... just saw the attachment and the manufacturer has indeed specified that you can use both tyre sizes. You're all good.

EDIT 2: Corrected a typo

Edited February 25, 2016 by Davy

nsiva · April 28, 2015

Rider, I think I was wrong. I now presume the 2nd tyre is an option.

Since the second size is given by manufacturer it can not go wrong (such as scraping wheel well etc.)

Only thing i though was these two tyres have different dimaters. The odometer may slighly deviate.

then only I found out this:

175*70%=122.5mm (nominal)

185*70%=129.5mm

What I thought is manufacturer should have selected a 185*65R14 tyre=>

Then, 185*65%=120.25mm (lower than the 1st size)

That is why he has given a slighly higher tyre diameter (185*70R14)

I think, you should have no problem in changing to the 2nd tyre size, as it is manufacturer recommended and already he has made calculations!

nsiva · April 28, 2015

right side of your label refers to the tyre pressure = 2.1kg/cm2 = 30psi.

If this is less also, (you dont have enough tyre pressure), your ground clearance can reduce.

Bottom refers to your spare wheel deatils. that also actually confusing. My honda car has only one clear size for everything. LOL.

Rider · April 28, 2015

thanx guys! I think Im gonna go with 185/70R14 tires set.

PreseaLover · September 19, 2015

What can be the main factors that determines the tyre size of the car? (13, 14 etc.?)

Asking because my 1500cc presea has a tyre size of 13 by default... but my friend who has the same model 1500cc presea has a factory fitted tyre size of 14... so how come the same model vehicle come with different tyre sizes?

WCW · September 21, 2015

On 9/19/2015 at 4:11 PM, PreseaLover said:
What can be the main factors that determines the tyre size of the car? (13, 14 etc.?)
Asking because my 1500cc presea has a tyre size of 13 by default... but my friend who has the same model 1500cc presea has a factory fitted tyre size of 14... so how come the same model vehicle come with different tyre sizes?

Ok, might be your car came up with standard 13"steel rims and his car offered with 14" alloys. But again wall height & rim size is the factor determining total diameter of the wheel. Just an idea!

PreseaLover · September 21, 2015

On 9/21/2015 at 4:18 PM, WCW said:
Ok, might be your car came up with standard 13"steel rims and his car offered with 14" alloys. But again wall height & rim size is the factor determining total diameter of the wheel. Just an idea!

Ah that makes sense now... your probably are right...