HELP ON TIRE SIZE..., For 17's and 18's rims Options

[charming6gmoz]

I need help in getting the right fit of tires for the current rims I have.



A few days ago one of my front rims crack really bad in pieces going into a pot hole.

Right now my tires are 215/ 35 /18




I Want to increase the sidewall height to decrease the stiffness in my car
and wanted to know what is the highest height I can go
on the sidewall height for 18 inch rims and for 17 inch rims... ??????

The reason I want to know what is the highest I can go for 17's and 18's
is that the Company that make the rims I currently have doesn't make 18's anymore
and I have to place 17 inch rims in the front, but now I want to go the highest on the sidewall height..


Some people recommended me getting
215/ 50/ 17 for the front &
215/ 40/ 18 for the rear.

After i got my rims, the car became very stiff and
that is why I want to get bigger tires now so the impact
on the road won't feel as hard and the car can decrease the stiffness.

Is this the highest I can go on the tire size so none of the tires rub?
i would really appreciate your help..







This post has been edited by charming6gmoz: May 19, 2010 - 6:39 PM

[Projek_01]

Google up a tire size calculator like the one on the miata site. Enter the stock tire size of 205/55/15 and enter tires with a taller sidewall for your 18 inch wheels. Look at how many percent oversize that particular tire is. I would stay under 5 percent but that's just me. Only negative effect I had was my speedo was 5 percent off.

[AnaXyd]

If you go 18's, I think the ABSOLUTELY most is 40. I got 18's with 35 now, and they are almost rubbing when turning over at max. I think its place for a little more. But I dont think you will feel any difference from 35-40. If you want it more comfortable, you have to go down to 17's, with 50 or something. 18's are NOT comfortable on our cars without modifications.

[charming6gmoz]

If you go 18's, I think the ABSOLUTELY most is 40. I got 18's with 35 now, and they are almost rubbing when turning over at max. I think its place for a little more. But I dont think you will feel any difference from 35-40. If you want it more comfortable, you have to go down to 17's, with 50 or something. 18's are NOT comfortable on our cars without modifications.

What type of modifications do u think I need to do if I stay with 18's rims?

[GriffGirl]

Um, as far as I know, 215/50/17 doesn't even fit our car. Anyway, it's not the 50 part that increases the sidewall, that's the width. It's the 215 part that's the sidewall height.

On 17" I believe the biggest that will fit our car in the front for 17" rims is 225/45/17. If you want a softer ride, you need to DECREASE the size of your rims to allow for more sidewall. 16" rims would be a good option for this - they still look good, and give you room for that sidewall cushion you're after. I believe you can go 235/50/16, but don't quote me on that, you should research it first.

[Tom_SS2]

Um, as far as I know, 215/50/17 doesn't even fit our car. Anyway, it's not the 50 part that increases the sidewall, that's the width. It's the 215 part that's the sidewall height.

sorry bud but you're a bit wrong there, its a combination of both, in the most basic terms; 215 is the tyre width, 50 is the profile (side wall) and its the percentage of the width (so 50% in this case), 17 is the wheel size

At first glance the lettering on the side of the tyre may look complicated. It is not meant to be that way.
The lettering explains the exact specification of the tyre you have. In short it tells you anything that you
may need to know about your tyre.

From the diagram above we will try to break down what the codes and numbers really mean.
The codes on the above tyre, will be different on every tyre, due to a few main factors; the tyre width,
tyre profile, tyre size and the speed rating.

The number 165 relates to the Tyre Width
It is the width of the tyre in millimetres.

The number 65 relates to the Tyre Profile
It is the height of the tyre side wall as a percentage of the width. This is also known as the aspect ratio.

The Letter R relates to Radial Construction

The number 14 relates to the Tyre's Size
It is the diameter of the tyre's inner rim in inches

The number 79 relates to the Tyre's Load Rating
This is the Load Capacity of the Tyre

The Letter T relates to the Tyre's Speed Rating Value
This indicates the maximum speed for the actual tyre at full load

The E4 Mark
This is to display that the tyre has been tested as high quality by the European Regulatory Authorities.

This post has been edited by Tom_SS2: May 20, 2010 - 5:50 PM

[charming6gmoz]

Um, as far as I know, 215/50/17 doesn't even fit our car. Anyway, it's not the 50 part that increases the sidewall, that's the width. It's the 215 part that's the sidewall height.

On 17" I believe the biggest that will fit our car in the front for 17" rims is 225/45/17. If you want a softer ride, you need to DECREASE the size of your rims to allow for more sidewall. 16" rims would be a good option for this - they still look good, and give you room for that sidewall cushion you're after. I believe you can go 235/50/16, but don't quote me on that, you should research it first.

yeah, 215/45/17 sound pretty good to obtain more sidewall cushion, I can't go for 16's rims cause I alrady have these,
and I don't really want to spent more money on buying new rims that is why I'm looking into see what is my best option on tire size.
thank you, that was great help.

[charming6gmoz]

Um, as far as I know, 215/50/17 doesn't even fit our car. Anyway, it's not the 50 part that increases the sidewall, that's the width. It's the 215 part that's the sidewall height.

sorry bud but you're a bit wrong there, its a combination of both, in the most basic terms; 215 is the tyre width, 50 is the profile (side wall) and its the percentage of the width (so 50% in this case), 17 is the wheel size

At first glance the lettering on the side of the tyre may look complicated. It is not meant to be that way.
The lettering explains the exact specification of the tyre you have. In short it tells you anything that you
may need to know about your tyre.

From the diagram above we will try to break down what the codes and numbers really mean.
The codes on the above tyre, will be different on every tyre, due to a few main factors; the tyre width,
tyre profile, tyre size and the speed rating.

The number 165 relates to the Tyre Width
It is the width of the tyre in millimetres.

The number 65 relates to the Tyre Profile
It is the height of the tyre side wall as a percentage of the width. This is also known as the aspect ratio.

The Letter R relates to Radial Construction

The number 14 relates to the Tyre's Size
It is the diameter of the tyre's inner rim in inches

The number 79 relates to the Tyre's Load Rating
This is the Load Capacity of the Tyre

The Letter T relates to the Tyre's Speed Rating Value
This indicates the maximum speed for the actual tyre at full load

The E4 Mark
This is to display that the tyre has been tested as high quality by the European Regulatory Authorities.

This is pretty good info, sometimes is hard when it comes to read tires, but I guess everything is easy once
u really look at it, that's right the second number on the tire size is always the % of the width which is always
in milimeters.

[k-weaver]

I think Tom is right on the money. For example, i'm running (just ran out to the car to double check as I think in another post I posted my wrong size >.<) a 225/40/18. If you run a 215/40/18 our sidewalls will NOT be exactly the same height because there is a relation between the tire width and sidewall height.

With my size tires/rims i've never once rubbed on anything and my car is lowered. It does "look" like it comes close however it never has nor probably ever will rub. That being said, I think you'd be fine with a 215/45/17 size tire.

I think a 35 is way too small. Keep in mind that this will cause your speedo to be off. May not be much, may be alot. Either way, it will not be exact. Worst case scenario, go to a reputable tire shop and ask what they recommend.