Tyre Profile Question

evans1089

evans1089

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My original 19" Audi alloys have 255/45/19 tyres on them.
I'm looking at winter tyres.

Would it be acceptable to fit 255/50/19?
They're also listed as for 'BMW's'.

What, if any are the implications?
I have adjustable air suspension.

Cheers
 
They would be an inch bigger diameter overall and may come into contact with the body or suspension in certain conditions. I honestly don't know if they will be ok but why not fit the proper size tyres?


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Ad72 said:
They would be an inch bigger diameter overall and may come into contact with the body or suspension in certain conditions. I honestly don't know if they will be ok but why not fit the proper size tyres?


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Click to expand...

Can't find any cheap enough to go on my old set of rims. These are £100 a tyre and nearly new.
I better keep looking then
 
Just get one fitted and try it? Or maybe just see if you have more than 1/2" clearance around your current wheels dia in the various suspension modes with various steering angles. My gut feeling is that they would be fine but your speedo would read slow.


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Citing bigger tires will increase the rolling distance which will impact on your speedo, in the 4x4 off-roading world where fitting ****** tyres is coming this is a known problem, some solve it by changing the diff gearing whilst others get their Speedos recalibrated... others just ignore it and keep up with the traffic ;)

But the biggest issue which Ad72 has already highlighted is the physical size which may cause rubbing


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Had a look under my allroad today fitted with 255 40 20's and the clearance between the tyre and top ball joint is pretty tight. 255 50 19's will be pretty close, no problems on the rears.


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Don't know is the bigger profile is an optional fit for your car, but if you have access to VCDS, you can select the different tyre size for speedo calibration.
 
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I only suggested this size because of the price of these goodyears I've found. Just didn't fancy paying £800 for a new set before Christmas and only using them for a couple months or so
 
evans1089 said:
Would a smaller profile like your 40 be acceptable?
Click to expand...

Correct sizes are 255/40/20 or 255/45/19 which are near as damn it the same dia. A 255/40/19 would IMO be fine if the price is attractive.


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I'm also looking to fit a different size for the summer wheels
The Allroad standard is 255/40 R20 and the new Ispiri wheels wich I have bought have 10J wide with ET35 and want to fit 265/40 tyres also Goodyear F1 Asymetrical AO
I'm a little concerned of the front wheels rubbing, the back are wide enough
What do you recommend
Thanks

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cata_adc said:
I'm also looking to fit a different size for the summer wheels
The Allroad standard is 255/40 R20 and the new Ispiri wheels wich I have bought have 10J wide with ET35 and want to fit 265/40 tyres also Goodyear F1 Asymetrical AO
I'm a little concerned of the front wheels rubbing, the back are wide enough
What do you recommend
Thanks

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Click to expand...
I don't think going an extra 10mm on tyres is going to be a major issue, what wheels are you putting them on? Factory offset is ET45?
 
Thanks for the reply @jojo
I will put the Ispiri ISR6 with ET35 and 10J front and back
The standard dimensions on 10J will be fully stretched

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Here is a theoretical comparison of standard 8.5J ET43 20's vs your new setup.

EXISTING NEW

Diameter
712mm 720mm

Circumference
2236.8mm 2261.9mm

Hub to rim edge outer
65mm 92mm (stick out 27mm more)

Hub to rim edge inner
151mm 162mm (protrude in 11mm more)

Speedo error
0% -1.11%

Reading at 30mph
30mph 29.67mph

Reading at 60mph
60mph 59.33mph

Ride height gain
0mm 4mm

Arch gap loss
0mm 4mm
 
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cata_adc said:
Thanks for the reply @jojo
I will put the Ispiri ISR6 with ET35 and 10J front and back
The standard dimensions on 10J will be fully stretched

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Click to expand...
Ahh right, with the lower offset and extra rim width is like a double whammy of clearance issues. Won't know until you fit them basically. The rolling radius isn't too much of an issue in my opinion.
 
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audi upgrades
Thanks guys
My single concern is the hub to rim edge inner on the back wheels the 11mm protrude.
I will try to measure with my winter setup how much gap is there now
It isn't such a great difference between the 255 and 265
Many told me to put 275/35 but the rolling radius is aprox 3.4 mm smaller than the standard 255/40
It isn't a track day car it's a family all-rounder that I want to look good with 20 inch wheels :)

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