Hey guys what size tyre would you put on a 17x7.5" rim

seems to vary between a 225/45 and a 235/45.

235/45 is as close to the factory diameter. Just wondering if a 235 would be over tyred.

I used to have a 235 width tyre on a 7.5" wide rim
Never had any issues with this

Hey guys what size tyre would you put on a 17x7.5" rim

seems to vary between a 225/45 and a 235/45.

235/45 is as close to the factory diameter. Just wondering if a 235 would be over tyred.

factory fit is a 225/50 ... but thats an usual size and you'll pay more as a result.. ive always gone with 235/45s on that size rim.... no issues for me either...

factory fit is a 225/50 ... but thats an usual size and you'll pay more as a result.. ive always gone with 235/45s on that size rim.... no issues for me either...

:stoopid:, my 19's are 7.5" wide and they have a 235/35/r19

the're some big profile 19's..

7.5x18x235/40

factory 17 rims are 7 inches wide. 235 45 tyres are against road regulations, however that is what i run on mine. 7.5 inches wide aftermarket 17s are fine with a 235 45 tyre though . Just watch out for the load rating for your particular model

Your best options are 225/50/17, or 235/45/17. for a 17x7.5

Personally I recomend 225/50, despite the slightly higher perice due to being a less common size. Why? Because on a 7.5" wide rim 225 is gonna look and feel better to drive. 235 bulges slightly on a 7.5" rim, which doesn't look as good, and leads to more sidewall flex under hard cornering.

Also your rolling diamater is a little too small with 235/45/17. Not to any huge extent, but it's enough of a difference that your speedo/odo will be a few % out. Also when I had 235 tyres, I found the wheel arch gap looked noticeably bigger, giving the impression of a higher ride height.

I ran 235/45, I now run 225/50 and am happier with this.

I run 235/45/17 on S2 VRX rims. Feels good, drives great

:stoopid:, my 19's are 7.5" wide and they have a 235/45/r19

?? Are you sure? That wheel/tyre combo must scrub a lot! :badgrin:

?? Are you sure? That wheel/tyre combo must scrub a lot! :badgrin:

my bad, it was a typo

With tyre replacement there are a number of other considerations:

1. What was original tyre/wheel size because of legal implications. Changing the door pillar sticker can fix this(see later posts for clarification)

If you had 215/60 x 16 standard then replacement must be within 15 mm dia of that size and have at least 95H load rating. In 17" that means using a 235/50 x 17, or 225/55 x17. Change the door sticker to VR-X 17" wheel sticker and other sizes become "legal"; 215/55 x 17 and 225/50 x 17, also 235/45 x 17 and 245/45 x 17 rated above 94H

2. Replacement tyre tread width because it can vary up to about 25mm for same size tyre depending on tyre brand & model.

Basically for soft wall road tyres you need 1" wheel width for every 1" tread width for best grip and tyre wear. Up to about 1.035" tread to 1" wheel is OK but if tread is wider the tyre will roll and wear more on the shoulders and not grip very well unless you use very high tyre pressures.

If you measure different brands of tyres you will find big differences in tread width for the same tyre size. Just as an example 215/60 Bridgestone Turanza is about 6.25" tread width while Bridgestone Grid III is over 7.1". Many 215/55, 225/50, 225/55, 235/50, 235/45 have nearly the same tread width - most performance models about 7.7" - 7.8" of tread, but they can be as narrow as 7.1" up to over 8.2". And when measuring tread width remember that new tyres are narrow and get about 0.3" - 0.35" wider as they wear.

Note that even though performance 215/55 have around 7.7" -7.8" tread width you should not use a wheel more than 7.5" wide unless the tyre manufacturer says it OK. Also 235/45 should NOT be fitted to 7" wheel; 7.5" is the minimum.

3. Ride comfort

Higher walls mean more ride comfort and less thump over small road ruts and bumps. So at the same pressures 235/45 will be roughest and 225/50 & 245/45 next worst. 235/50 and 215/55 will give similar to stock ride.

4. Handling when close to no tread and wet road

Wide tread means very little wet grip when tread depth is less than about 3.5mm due to water having to be physically moved further from center of tread. Also less contact pressure as car weight is spread over bigger area and less able to squeeze water from beneath tread.

Wider tyres tend to be made with shallower tread anyway and most Asian brands use full tread depth only on the main 4 or 5 rain channels. This means that at 1.6mm legal tread depth the tyre looks like a F1 slick. European tyres (and some Asian tyres eg Maxxis) tend to have full tread depth right across the tyre so its safer to run these right down to the legal limit.

A low wall wide tyre generally gives less feedback when about to let go and this is worse when its wet.

Cheers, Alan

Interesting!, had never really thought about those differences in tread depths before,what with everything else you have to keep in mind when choosing tyres.

no wonder my 245/30/R20 have little grip in the wet

Sorry I need to add a PS to my post. The 15 mm dia change relates to law in NSW. Other states are different.

Cheers, Alan

1. What was original tyre/wheel size because of legal implications.[/B] Changing the door pillar sticker can fix this

If you had 215/60 x 16 standard then replacement must be within 15 mm dia of that size and have at least 95H load rating. In 17" that means using a 235/50 x 17, or 225/55 x17. Change the door sticker to VR-X 17" wheel sticker and other sizes become legal; 215/55 x 17 and 225/50 x 17, also 235/45 x 17 and 245/45 x 17 rated above 94H


this is incorrect... you might fool a cop on the side of the road with your new sticker but it doesnt make it legal...

Should have checked my reply before submitting. Meant "legal" not legal. I'll fix up the mistake.

However that said I've been told Mitsubishi instructed dealers to replace the pillar sticker when optioning up new cars on the showroom floor from 16" to 17" wheels because the 225/50 x 17 load rating was only 94H and not 95H.

Can anyone with dealer contacts confirm?

Cheers, Alan

I run 235/45/17 on S2 VRX rims. Feels good, drives great

I assure you 225/50 feels better :)

Interesting post as i have just bought and fitted a set of TL VRX wheels with 225/50/17s and i reckon it rides even better than the 215/60/16 Toyo's i had on....but the noise...omg...:nuts:

I assure you 225/50 feels better :)

What width wheels are those 225/50s on Chisholm, and how wide was the tread on your 235/45s?

For absolute best cornering and steering feel on soft wall road tyres, as compared to R-spec and race tyres, I really like the wheel width to be equal to the tread width plus 0.5". Thats a bit impractical though as unfortunately you often can't get a wheel that wide under many cars, and there is a lot more wheel sticking out so there is more risk of kerb damage. Also it can be over the max width the tyre maker specifies in some tyre sizes(eg many performance 215 section tyres have well over 7.5" tread but the max allowable wheel is usually only 7.5"). Consequently I now say you need 1" wheel width for every 1" tread width for best grip and tyre wear. Up to about 1.035" tread to 1" wheel is OK but if tread is wider the tyre will roll and wear more on the shoulders and not grip very well unless you use very high tyre pressures.

Another rough and dirty rule of thumb I tell lazy guys is to multiply the wheel width by 30, and thats the tyre section width to use for good tyre wear and steering feel. Conversely if you divide the tyre section width by 30 that tells you what wheel width to use.

Cheers, Alan

I assure you 225/50 feels better :)

Really? is there much difference in handling?

I drive pretty hard through the national parks so really lookin to make the car handle and grip as well as possible.

Currently got Kuhmo Ecsta SPT 235/45/17 on the rears and Toyo's (dont know the model) 235/45/17's on the front.

Frankly the Kuhmos were awesome while these new Toyos which I got under advice from a mechanic, although they grip pretty good, have road noise which wasn't there before.

What width wheels are those 225/50s on Chisholm, and how wide was the tread on your 235/45s?



Both on a 7" wide rim. I'd prefer 7.5-8" even with the 225/50, but for the street I don't care all that much. On the track I run 235/45 on a 8" wide rim, but for my next set of semi-slicks I mayt go 225/45. I'm also a fan of 'oversizing' the rim for the tyre a little.


Really? is there much difference in handling?



When I went from 235/45 to 225/50 on a 7" rim (same width as your VRX rims), there was a noticeable difference to me. However I went from Maxxis MA-Z1 to Federal 595s, and I suspect the latter has stiffer sidewalls anyway, so hard to say how much of the differece was due to the change in tyre size.

This was when I had the King Lows/KYB setup. My current setup has over double the spring rates of the King Lows and generates much more grip lateral grip - I find with 225/50 on 7" I can feel alot of sidewall flex under hard cornering, whereas with the old King Lows/KYB it felt pretty good.

Next time you replace your tyres, I'd suggest 225/50 on those rims, or even 215/55 (OEM size for 380s wich also have a 7" wide rim from memory)

Can somebody please explain to me exactly what these numbers mean? For example 235/45/R17. I understand the 17 bit (17" wheels for the rims). But what do the first 2 numbers mean?

Can somebody please explain to me exactly what these numbers mean? For example 235/45/R17. I understand the 17 bit (17" wheels for the rims). But what do the first 2 numbers mean?
The 235(mm) is the Width of the tyre, and the 45 (4.5inches) is the length of the firewall (ie, the length between the rim and the tread. correct me if I'm wrong?

__________
| |4.5"
| |___
| Tyre |
| |17"
| |___
| |
--------
|23.5cm|

lol if that makes sense... haha prob wld have been easier to just upload from paint but meh :P

edit: grr, it takes out the spaces I put in... oh well :P

the're some big profile 19's..
on my 19x8 i had 245s lol
http://i12.photobucket.com/albums/a230/micjaiy/MICHAELSCAR009.jpg
http://i12.photobucket.com/albums/a230/micjaiy/100_0954.jpg

Can somebody please explain to me exactly what these numbers mean? For example 235/45/R17. I understand the 17 bit (17" wheels for the rims). But what do the first 2 numbers mean?
http://www.1010tires.com/tech.asp?type=tires_general#sizing

The 235(mm) is the Width of the tyre, and the 45 (4.5inches) is the length of the firewall (ie, the length between the rim and the tread. correct me if I'm wrong?



235 = width, (mm) of tyre
45 = sidewall as a % of width. (in this case 45% of 235mm)

The question what do the numbers 235/45 x 17 mean is a good one. And the real answer is not much. Apart from the 17, which means the tyre beads are 17" across to fit a 17" diameter wheel all the other numbers are pretty fudgy(rubbery?)

Tyre makers are able to play the "numbers game" as tyres were originally hand made, some still are or semi-hand made. Being hand made manufacturers were given a good allowance for "production tolerances". Basically a loophole you could drive a truck through with regard to actual tyre size. The tolerance can be as much as 2% in some areas and to top things off the tyre can be measured on any suitable size wheel. Consequently a 235 section tyre can be 235mm wide, plus or minus the "production tolerance" on anything from a 7.5" to a 9" wide wheel, and some makers say up to a 9.5" wheel is OK! So if you want to make a relatively narrow, nominally 235 tyre, pass as a 235 then you measure it on a wide wheel. Or if you want to make a thats actually more like a 245 or 255 tyre then you measure it on a narrower wheel and label it 235. Thats why it important to know the tread width and use a tyre that is matched about 1" tread width for 1"wheel width.

A good source of tread widths is tirerack.com, but some of their numbers are not correct. There you can see how much variation there is between tyres of the same nominal size, and how close are the dimensions of tyres that should be very different. eg many 215, 225, 235 have similar tread width. As I've stated previously even within the same brand there can be a difference of nearly 1" in tread widths for tyres of the same marked size. Generally standard type tyres are narrowest, performance tyres a bit wider and ultra high performance wider still. Then you have R-spec, usually wider again.

The /45 is not wall height of 4.5", but is about a nominal 45% of the nominal tyre width. Some sizes are close to the theoretical height and others aren't.eg a 215/55 x 17 has a diameter of about 663mm. Minus the 17" wheel and divide by 2 and you have a true wall height of 115.6mm. The theoretical wall is a bit taller; 215mm width multiplied by 0.55(55%) is 118.25mm. If you look at overall tyre diameters you will again see quite a bit of variation. Continentals tend to be bigger in diameter than all other brands.

From earlier posts it seems quite a few Magna owners are using 235/45 x 17 tyres on 7" wide VR-X and 380 wheels. Don't; 7.5" is the minimum width for 235 tyres, and generally 8" or 8.5" is better for wear and handling. The maximum tyre width for 7" wheels is 225, but its better not to use wider than 215 on a 7". I actually think 205 is the best for 7" wheels. A good rough guide is to divide the tyre size by 30, and that gives the wheel width you need.

Cheers, Alan