Tyre aspect ratio

[coolraj003]

My 07 2.0tdi has 225 50 17 tyres currently and I have been looking to get some winter tyres for the car but most of the ones on ebay are 225 45 17. My question is what impact would it make if i get the 45 aspect ratio rather than the ones with 50. Obviously I will be changing the summer tyres as well eventually and was hoping if 45 aspect ratio would do as they are quite common and less pricey than the 50. Any opinions suggestions please?

Raj

[joshA6]

The difference in rolling circumference between the 2 sizes will be much greater than the 2%. In fact, it is around 3.5%. So when your speedo reads 70, you will actually be doing 67.

I got these figures by googling for 'wheel size calculator' which allows you to play around with just that.

You can use a 45 profile, but you will probably need a wider tyre, like a 235.

Whats the price difference between the 2????

[coolraj003]

well does that mean I would have to recalibrate the speedometer for changing the tyres. Now the thing is I might permanently shift towards the 45 aspect ratio tyres whether summers or winters. The price difference between them was about £25 per tyre to be honest and im on a budget at the moment so would like to squeeze as much as I can. Wont a wider tyre sort of defeats the objective as wider tyre would literally act as a sledge instead of cutting through the ice if it was a bit narrower? would i be better off getting new rims or existing ones for wider tyres?

what purpose would a wider tyre serve? any things i need to look out for..i mean any adverse affects with regards to ride and handling?

Raj

[nealeb]

Problem is that you need to go to a 245/45 to replace a 225/50 to keep the same diameter - and as you say, the wider tyre somewhat negates the use of winter tyres which are generally narrower than standard rather than wider. Don't know if the speedo can be recalibrated to suit (seems highly unlikely) and in any case you are outside the "Audi recommended" sizes which might possibly give insurance difficulties.

As far as the speedo is concerned - in principle you are allowed max 10% error (as long as speedo overreads - underreading not allowed). Using a GPS to check various Audi speedos they seem to typically overread by about 6%. Add in the tyre-size error and you are getting close to the legal limit on speedo error - although it's not likely that anyone would notice.

[A6quattro3.0]

It not an answer to your question I know, but do you have to go for a different size tyre ? I have just ordered like for like (except the speed rating) from mytyres.co.uk. Only £55 each, delivered for 225/50/ R16 H XL

[neilos100]

Did you really mean 225 50 16?

[A6quattro3.0]

Did you really mean 225 50 16?

Well spotted. I have ordered :

Goodride SW601 225/55 R16 99H XL asymmetric (Wi)

[neilos100]

Interested to know if anyone has the 205 60 16 profile winter tyres. These are one of the sizes on the sticker on the b pillar on my car. Surely they must be the cheapest size option and also the most effective due to their narrowness...

Sent from my HTC Desire using Tapatalk