Different tyre sizes on the same car?
Different tyre sizes on the same car?
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Discussion

fjord

Original Poster:

2,143 posts

167 months

Tuesday 11th December 2012
quotequote all
Was just putting some air in the tyres and struggled to locate the actual size on the sticker at the a-pillar of the car.

It's only when i looked all around, i saw that i have the following:

Both Front tyres - 215/45/18
Both Rear tyres - 255/35/18

I forgot to check the speed rating. Is this dangerous and/or illegal and will it affect me in any way? Vehicle is an E46 320.

jackh707

2,132 posts

186 months

Tuesday 11th December 2012
quotequote all
fjord said:
Was just putting some air in the tyres and struggled to locate the actual size on the sticker at the a-pillar of the car.

It's only when i looked all around, i saw that i have the following:

Both Front tyres - 215/45/18
Both Rear tyres - 255/35/18

I forgot to check the speed rating. Is
this dangerous and/or illegal and will it affect me in any way? Vehicle is an E46 320.
You have different sized wheels because it's rear wheel drive. Most BMWs are like this.

TheEnd

15,370 posts

218 months

Tuesday 11th December 2012
quotequote all
http://www.miata.net/garage/tirecalc.html

It's not usually a problem, many cars do come with different tyre sizes but in your case there is a bit of a "gap" between them

I guess the front tyre was meant to be a 225/40/18 and someone has either been sold the wrong type, or just went for something cheap.

fjord

Original Poster:

2,143 posts

167 months

Tuesday 11th December 2012
quotequote all
Ok thanks guys, i'll leave it smile

TheEnd

15,370 posts

218 months

Tuesday 11th December 2012
quotequote all
Keep an eye out for traction control flashing away on the motorway, as in that case it can be a problem for you.

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
jackh707 said:
You have different sized wheels because it's rear wheel drive. Most BMWs are like this.
Cars don't have to be RWD to have different sized wheels front to rear. smile

The numbers above look pretty standard for a "sporty" 3-series to me, although I'm surprised there's so much difference in a 320.

MondeoMan1981

2,458 posts

213 months

Tuesday 11th December 2012
quotequote all
205/50/17 front and 225/45/17 on the rear of my 120d , caused a bit of a WTF moment when I noticed biggrin

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
MondeoMan1981 said:
205/50/17 front and 225/45/17 on the rear of my 120d , caused a bit of a WTF moment when I noticed biggrin
I've got 175/55/R16s on the front and 225/45/R17s on the back, so not even the same diameter wheels. hehe

RobCrezz

7,892 posts

238 months

Tuesday 11th December 2012
quotequote all
kambites said:
jackh707 said:
You have different sized wheels because it's rear wheel drive. Most BMWs are like this.
Cars don't have to be RWD to have different sized wheels front to rear. smile

The numbers above look pretty standard for a "sporty" 3-series to me, although I'm surprised there's so much difference in a 320.
Thats true, but its much much more common for a RWD car to have staggered wheels/tyres than FWD or AWD.

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
doogz said:
There have been a few 4WD ones, but I'm struggling to think of any FWD cars with different sized tyres front and rear.

Anyone?
The closest I can come is the RS3, which has wider fronts than rears; but of course it's 4WD.

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
doogz said:
Well yeah, that was the first one that came to mind, plus Veyron and a few Lamborghinis, but I can't think of any FWD ones?
In fact (possibly asking the same question) is the RS3 the only car that's had wider tyres on the front than the rear?

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
Apparently the Pontiac Grand Prix GPX was front wheel drive with wider fronts than rears.

A V8 too, so it probably needed them. hehe

Ozzie Osmond

21,189 posts

276 months

Tuesday 11th December 2012
quotequote all
doogz said:
I'm struggling to think of any FWD cars with different sized tyres front and rear.
Rear wheels have very little work to do on an FWD under normal circumstances, so same size wheels are mainly fitted for convenience and to enable rotation. One of the main advantages of proper 4-channel aBS is to prevent early rear-wheel lock-up.

You will often see tiny disc brakes (much smaller than the front) or even good old-fashioned brake drums on the back of an FWD car.

Captain Muppet

8,540 posts

295 months

Tuesday 11th December 2012
quotequote all
kambites said:
In fact (possibly asking the same question) is the RS3 the only car that's had wider tyres on the front than the rear?
I once saw a mk2 MR2 for sale at a back street dealer where they had swaped the front and rear wheels over. Both wheels looked the same, but the front was a 15x7 with a 225 tyre and the rear was a 15x6 with a 195 tyre. They were shut at the time so I couldn't let them know they'd been stupid.

I can't think of any FWD cars that use wider tyres on the front.

LuS1fer

43,517 posts

275 months

Tuesday 11th December 2012
quotequote all
The Lotus Esprit came with different fronts and rears, I originally had 275s all round on my Mustang but have reduced the fronts to 255s.

The main issue is keeping the same rolling radius as the original fitment by playing with profiles otherwise the spare wheel will be the wrong size. As mine is, the spacesaver is still the right size front and rear although stwing the 275 is an issue as it tends to fill the boot.

Edited by LuS1fer on Tuesday 11th December 14:29

mr_spock

3,374 posts

245 months

Tuesday 11th December 2012
quotequote all
Porsche 928 has different fronts and rears.

margerison

1,003 posts

280 months

Tuesday 11th December 2012
quotequote all
Sorry to thread hijack...slightly bandit

I have 285/45/R19 on the rear and 255/50/R19 on the front (I think).
My 'full size' spare is 17", am I boned?! (It's 4x4)

TheEnd

15,370 posts

218 months

Tuesday 11th December 2012
quotequote all
You might find the circumference of the spare matches the larger 19's

kambites

71,540 posts

251 months

Tuesday 11th December 2012
quotequote all
margerison said:
I have 285/45/R19 on the rear and 255/50/R19 on the front (I think).
My 'full size' spare is 17", am I boned?! (It's 4x4)
That's fine as long as the rolling radius is the same.

Prof Prolapse

16,163 posts

220 months

Tuesday 11th December 2012
quotequote all
I changed my tyres years ago on the Jag to replace the front with smaller ones.

My theory was that it reduced the tramlining. It did seem to work IIRC.