bmw z3 2.8 18 inch rear tire size 255 vs 245?

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babyjason

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Jul 28, 2021
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Hello,
I googled alot but i cannot find a concrete answer.

I have a 18 inch wheel rear , currently at 255/35/18 run flats, but the tyre looks like it sticks out over the rim with like 1-2 cm. I was thinking 245/35 normals would be more suitable.

Anyone running 245/35 18 ? any idea if i should stick with 255 or 245?

I am running now also spacers that makes the wheel stick out a bit on the outer limits of the fender,that is why also a bit lower profile would be nice i think.

ty
 
babyjason said:
Hello,
I googled alot but i cannot find a concrete answer.

I have a 18 inch wheel rear , currently at 255/35/18 run flats, but the tyre looks like it sticks out over the rim with like 1-2 cm. I was thinking 245/35 normals would be more suitable.

Anyone running 245/35 18 ? any idea if i should stick with 255 or 245?

I am running now also spacers that makes the wheel stick out a bit on the outer limits of the fender,that is why also a bit lower profile would be nice i think.

ty
Click to expand...
Hi mate, my winter wheels are staggered 18" MV3s on the same tyres though not run flats as they're wheel breakers (personal experience). I don't use spaces as not required. My Summers are Style 78s (245), a better ride as there's more give in the tyre wall.
 
Few members run other bmw model 18 " alloy wheels usually with 225/40/18 on front and 255/35/18 on rear.
You could run the 245/35/18 but I would imagine tyres will have less options and possibility of not being any cheaper could you not buy a slightly smaller spacer and pull the wheel in a bit and stick with the 255 rear .
Stephen.
 
He was talking about putting a 245/ 35 / 18 on the current rim instead of the 255
 
yes on my current 18 inch 255/35 tyres i want to put 245 instead of 255 as i have now, because it seems the tyre goes way outside of the rimm. on the fron i have 225 /40 18 and it seems to be less on the outside of the rimm.

Also there is no official fitment guide for 18s on z3, cuz for z3 max was 18...

I will make a pic when i have time, i need to buy 4 new tyres , the price difference is irrelevant.
 
Yeah z3 never came with 18
Largest tyre combo was 225/45/17 front and 245/40/17 rear.
 
I totally understand your struggle to find a concrete answer to your BMW Z3 tire size question. It can be frustrating to not know which size to choose for your car.
I recently stumbled upon a tire size calculator that could help you make a more informed decision. I used TireSizesCalculator.com and found it to be super helpful. It allowed me to compare different tire sizes and see how they would affect my speedometer reading, ground clearance, and overall performance.
In terms of your specific question, I have seen some BMW Z3 owners go for the 245/35/18 size and be happy with it, while others prefer the 255/35/18. It really comes down to personal preference and what you think looks best on your car.
One thing to keep in mind is that if you're running spacers that make your wheel stick out a bit, going for a lower-profile tire could help balance out the look of your car.
 
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You need to be telling us about the width and offset of the rim, not just the diameter, as the width will dictate what width tyre you need - and then you can decide on the profile. And the offset will help determine where your wheel will sit inside the arch. But as has been said, 245/35R18 is a lesser used tyre size and may be more expensive or harder to get, whereas 255/35 tyres are pretty standard for anything from 8J-9J width rims.
 
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this is a great site for checking the best size tyre for a party rim width, compare offsets, calculate speedo error form different diameters etc:
tiresize.com

TireSize.com - Compare Tire Sizes, Specs, Prices & more

Use our tire size tools to calculate specs, speed, gear ratios and more. Browse tires by size, vehicle, or brand and compare prices online all in one place.
tiresize.com tiresize.com
 
Dino D said:
this is a great site for checking the best size tyre for a party rim width, compare offsets, calculate speedo error form different diameters etc:
tiresize.com

TireSize.com - Compare Tire Sizes, Specs, Prices & more

Use our tire size tools to calculate specs, speed, gear ratios and more. Browse tires by size, vehicle, or brand and compare prices online all in one place.
tiresize.com tiresize.com
Click to expand...

These type of sites are good for comparisons but that is not what this guy was asking. Hopefully he is going to give us his current wheel specs and then people can help him achieve the look he is wanting from his car.
 
Hmmm agree with Mr Box...I was looking at some MV2 style 18" wheels and discovered the ones from the E60 have a very different offset (20) from the ones off the E46 (50). A 20 offset with a 255 width tyre would be sticking out even on a widebody I guess?
 
as400 said:
Hmmm agree with Mr Box...I was looking at some MV2 style 18" wheels and discovered the ones from the E60 have a very different offset (20) from the ones off the E46 (50). A 20 offset with a 255 width tyre would be sticking out even on a widebody I guess?
Click to expand...

Stay away from E60 versions as MV2s from E46s are a great fit but will need a 10mm spacer on the rear to fill the arch better. The E46 MV2 is a 8.5J width on the rear with an offset of 50 and are factory fitted with 255/35s - you really can't go wrong with these.

Here's a really good guide to widths and tyre sizes for the Z3 and includes different options for narrow and wide body cars.

Click here for some factual wheel fitment info!!
 
Just a thought - has anyone ever asked for approval of oversized tyres from their insurer? Tyres may now be regarded as cosmetic items, but insurers would view such things as a good get-out clause. Here in France - and Germany - non standard tyre sizes could result in an MoT failure.
 
It’s one of the options under the Modifications section of an Insurance proposal Mike, has been for a very long time. Generally doesn’t carry much, if any, loading except/unless combined with other modifications. Varies from company to company, linked to various other actuarial factors.
Not ticking the box could render the Policy invalid in the event of a post accident investigation/inspection. As would any undeclared modification.
 
IainP said:
It’s one of the options under the Modifications section of an Insurance proposal Mike, has been for a very long time. Generally doesn’t carry much, if any, loading except/unless combined with other modifications. Varies from company to company, linked to various other actuarial factors.
Not ticking the box could render the Policy invalid in the event of a post accident investigation/inspection. As would any undeclared modification.
Click to expand...

Yep - even changing wheels from OEM to OEM needs declaring and as Iain says there really is no loading these days for this type of mod so always need declaring for peace mind.
 
Exactly, box for that too
‘Manufacturers alternative fitment’ I think it is, had to tick that last week for mine.

862 mile round trip to Bristol apparently, asked my lad to shadow me . “No way! Mum will kill both of us, not just you “
 
IainP said:
Exactly, box for that too
‘Manufacturers alternative fitment’ I think it is, had to tick that last week for mine.

862 mile round trip to Bristol apparently, asked my lad to shadow me . “No way! Mum will kill both of us, not just you “
Click to expand...

What a great road trip though..............
 
Not if he has to tow me 400 back🤣
His 318 once did well over 100 miles in the same condition without blowing up, so it is tempting, which is why I know the miles.
There isn’t a cheap Mot’d Z within 300 miles of Perth.
 
IainP said:
Not if he has to tow me 400 back🤣
His 318 once did well over 100 miles in the same condition without blowing up, so it is tempting, which is why I know the miles.
There isn’t a cheap Mot’d Z within 300 miles of Perth.
Click to expand...

Have you looked into car transporting companies? If it's three hundred or less then it could be worth it, i've genuinely no idea.
 
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