tyre width query

[purple charlie]

My C4 is running on 295/35 ZR18 Image 11inch alloys on the rear. The Michelin Pilots are cracking up from being sat for a few years. The fronts are 9.5 inch wide with 255/45 zr18 tyres.
not much choice for the rear tyres and trying to match with fronts.
I wont be doing many miles or fast track work.
my local dealer has suggested 285/35 zr 18 as an alternative and will save around £100 a tyre. the rims work out to be 280 approx, so is it ok to run the 285;s as an alternative. Rough working is the Pilots are £1100 for the set, the other option in Pirelli are £800. My main concern is living in rural areas with loads of pot holes £350 for rear replacement should it hole would be expensive.

 

[Roscobbc]

I have been running 285/40/18 Toyo's on the rear of my C3 for 10 years or so. 285's in an 18" size are getting a little scarce (and correspondingly expensive) - I will be replacing them next year (as they are 'going-off' a lttle in terms of traction). My intention was to replace them with 275/40's which seem to be a more popular size, less expensive and available from more manufacturers. The difference in total tyre height between a 285 and 275 is less than half an inch and will make a very small difference in gearing/speedo accuracy and perhaps reduce rear-end ride height by 5mm (quarter inch).
There's a useful American tyre site that allows you to feed-in and compare alternative tyre sizes with the OEM fitment.

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

And if finances are really tight there are budget options that are perhaps a third of the price of leading brands - how good they are is another matter though -

Search: 2 results found for ""275/40 R18"" – Tire Streets UK

Shop the best tyres online in the UK at Tire Streets. Choose from a wide range of premium and budget tyres. Next day delivery and 5% off your first order.

tirestreets.co.uk

 

[Eurovettes]

i can get tyres in from USA using tirerack.com - drop me an email for options keith keef@eurovettes.com

 

[Chevrolet]

my local dealer has suggested 285/35 zr 18 as an alternative and will save around £100 a tyre. the rims work out to be 280 approx, so is it ok to run the 285;s as an alternative.

Yes according to this. On those 11 inch wide rear wheels minimum tyre width is 275, recommended 285 or 295, maximum 305:

Min/Max Tire Size For Rim Width

Tire width can have a dramatic affect by creating more traction on dry road surfaces when using the maximum tire width. Or maybe you're interested in fuel effic

tiregrades.com

 

[Chevrolet]

And if finances are really tight there are budget options that are perhaps a third of the price of leading brands - how good they are is another matter though

Cant believe how cheap those Acceleras are at £60.65:

Accelera PHI 2 275 40 R18 103Y XL | Price and Reviews – Tire Streets UK

Buy Accelera PHI 2 275 40 R18 103Y XL tyres at the best price online. Get next day delivery on 275/40R18 Accelera PHI 2 tyres.

tirestreets.co.uk

I'm on my 2nd set of Acceleras on one of my daily drivers, Ian Goss at IGS American recommended them to me years ago. Ride, noise and braking seem to be just as good as the original Continentals? That's on a 140mph car that I just use for pottering about and never drive over 80mph.

 

[teamzr1]

Cant believe how cheap those Acceleras are at £60.65:

Accelera PHI 2 275 40 R18 103Y XL | Price and Reviews – Tire Streets UK

Buy Accelera PHI 2 275 40 R18 103Y XL tyres at the best price online. Get next day delivery on 275/40R18 Accelera PHI 2 tyres.

tirestreets.co.uk

I'm on my 2nd set of Acceleras on one of my daily drivers, Ian Goss at IGS American recommended them to me years ago. Ride, noise and braking seem to be just as good as the original Continentals? That's on a 140mph car that I just use for pottering about and never drive over 80mph.

If looking at those specs though, they are rated mid-class as not great for wet/traction and wear
Also, only Y speed rated

 

[Roscobbc]

Yes according to this. On those 11 inch wide rear wheels minimum tyre width is 275, recommended 285 or 295, maximum 305:

Min/Max Tire Size For Rim Width

Tire width can have a dramatic affect by creating more traction on dry road surfaces when using the maximum tire width. Or maybe you're interested in fuel effic

tiregrades.com

A 275 section tyre on an 11" rim may well be the supposed 'minimum' tyre width so is same width as rim........but isn't going to be very forgiving for the rims if you are unfortunate enough to even lightly scrape a kerb.......even the 305 is only an inch wider. I recall years ago with 15" rims there was a rule of thumb that a 50 or 60 section tyre should be as a minimum be 2 inches wider than the rim (allowing 1" sidewall additional width per side of rim)
And then you'll see something that is just plain ridiculous and really questionable in terms of any handling benefit and the likelyhood of body damage if something goes badly wrong

 

[teamzr1]

My C5 rear rims are 11.5 inches wide
Mounted are 335/30/18 and sidewall is fine

 

[Chevrolet]

Also, only Y speed rated

They changed the tyre max speed letters designations several years ago, certainly in the UK. The "Y" speed rating on the Acceleras above is is up to 186mph:
What Is A Tyre Speed Rating? Speed Ratings Explained

 

[antijam]

Anyone care to hazard a guess at the aspect ratio of these.......?

 

[purple charlie]

thanks all.
Ive now got the original salad spinner wheels for the mot now, so have more time to shop for something matching for the Image Alloys also time to polish them up!!

 

[Dorsetsteve]

Use a calculator such as this;

Tyre Size Calculator

A better easy to use tyre size calculator. Use our tyre size calculator to find tyre diameter, width, sidewall, circumference, and revolutions per mile.

tiresize.com

You can then see in real terms the difference in sidewall height etc etc. It’s a very small change. If you can get a better quality tyre for the same cost or the I would happily do that. I’d be more concerned about the design of the tyre than the aspect ratio as such at this point. Some cheaper tyres have no side wall meat that would protect that rim should you have a misjudgment parking etc and irrespective of the mileage and intended use the tyres are a literally all that connects you to the road.

 

[Chevrolet]

Some brands of modern low profile tyres have "rim protectors" built into the tyre. My VW daily driver has those on the original equipment 245/35/20 tyres on 8J x 20" wheels.

Which Tyres Protect My Alloy Wheels? | ASDA Tyres Blog

The scraping or scuffing of alloy wheels is a common problem, but there is a solution. Find out more about rim protectors at ASDA Tyres.

www.asdatyres.co.uk

Then there's those aftermarket rim protectors you can get (e.g RimBlades/AlloyGators):
Best Alloy Wheel Protection | Rimblades Rim Protectors

 

[Roscobbc]

It seems the newer the vehicle and wheel design the further the actual wheel centres protrude out past the wheel rims - so even if you avoid rubbing the tyre and metal extremities of the wheel rim against the kerb its almost a certainty that you'll scrape and damage the wheel center........and the issue will become worse in future years as tyre aspect ratios reduce and wheel diameters correspondingly increase...........car and wheel manufacturers really need to get together and design wheels with recessed centres that are 'behind' the wheel rims.......much like older vehicles with steel rims and hubcaps utilised.

 

[Chevrolet]

thanks all.
Ive now got the original salad spinner wheels for the mot now, so have more time to shop for something matching for the Image Alloys also time to polish them up!!

Or "salad shooters" as some people call(ed) them. Saw that new Morgan SuperSport "in the flesh" at a car show in September. The wheels on it a good imitation of C4 '84-'89 salad shooters I thought?