205/50 to 205/55 OK?

Ranger07 · 26 Oct 2010 at 11:02

paradigm said:
No rage

Just really confused how someone can see a radius difference of <1% with the naked eye.

You can get that much difference by tread wear.

Your wrong, a 195 will look stretched across a rim designed for a 205.

[TW]Fox · 26 Oct 2010 at 11:02

What's with the rage today paradigm?

paradigm · 26 Oct 2010 at 11:06

[TW]Fox;17652279 said:
What's with the rage today paradigm?

No rage

Just really confused how someone can see a radius difference of <1% with the naked eye.

You can get that much difference by tread wear.

spoogle · 26 Oct 2010 at 11:10

Just do what the rest of us did, ignore him as he is clearly talking porkies

..unless he is Chuck Norris, then I take everything back

Malc · 26 Oct 2010 at 11:13

Am I correct in saying that the difference in tyre height between 205/55 and 205/50 is:

205*0.55 - 205*0.5 = 10.25mm?

So 2.05cm difference in the diameter of the full wheel? Is this a big enough difference to fail your MOT on clearence whilst the car is in full lock?

spoogle · 26 Oct 2010 at 11:15

No, it will not fail

Ranger07 · 26 Oct 2010 at 11:18

Malc said:
Am I correct in saying that the difference in tyre height between 205/55 and 205/50 is:

205*0.55 - 205*0.5 = 10.25mm?

So 2.05cm difference in the diameter of the full wheel? Is this a big enough difference to fail your MOT on clearence whilst the car is in full lock?

It depends on the car and the original clearance, might be ok but you can't tell until you try it.

Malc · 26 Oct 2010 at 11:28

Ah, so the answer to the original question is. Put your car in full lock with the original 205/50's on. Measure the clearance. If it's greater than a CM at both the front and the back of the wheel then the 205/55's are ok!

Then, measure your speed with a sat nav and work out how your speedo now reads in realtion to true speed. If speedo's are over by around 10% anyway then the change of the new tyres shouldn't be a problem.

Ranger07 · 26 Oct 2010 at 11:37

That would work, or you could go down to 195's and there wouldnt be a problem as long as the tyres are the same on each axle.

Tesla · 26 Oct 2010 at 20:15

Thanks for all the replies. Cannot underhand the price hike on the correct size as they don't sound that uncommon. DRZ, how much are decent tyres for the st200 alloys (17").

Tesla · 1 Nov 2010 at 11:12

I've since found out that 205 55 fit fine to a regular Mk2 but if it's a Mk2 with RSAP the tyres will rub on the bumper brackets.

Jonnycoupe · 1 Nov 2010 at 11:58

The bigger issue is a foul with bodywork.

Pretty much anything like this sort of change will just make your speedo more accurate. The maths is silly to use anyway like it has been as it ignores tyre deflection that gives your real rolling radius.

I use 195/60/15 on my Focus now rather than 55 for the same reason and a bit more comfort. 195/50 were cheaper but would ground out getting on her parents driveway and they looked a bit silly in the arches.

DRZ · 1 Nov 2010 at 12:02

Tesla said:
Thanks for all the replies. Cannot underhand the price hike on the correct size as they don't sound that uncommon. DRZ, how much are decent tyres for the st200 alloys (17").

They are 215/45R17, which means you can get CS3s, RE050 (not the A though) or Pilot Exaltos.

I cant comment on the price as I don't buy tyres through the 'usual channels'.