225 50 17?

[amir2300]

Hi guys

Can anyone tell me if I will have any probelms fitting these on my 57 1.9cdti? It does not say anything in the book and I know alot of people upgrade to the 225 45 17. Has anyone tried this?

Cheers

[Derek Mc]

They will go on but the same problem as fitting 225/45 x 17 in that your speedo will under read by about 2% as the tyre will roll further per revolution than a stock 215/50 x 17.

I did notice a big difference between 215/50 and 225/45 it was a case of at 40 according to these solar speed boards that popped up, it reads 41 on 215's and 44 almost on 225's

[amir2300]

Thanks for that, so why do people get 225/45 rather than 225/50. 225/50 look to be cheaper!

[rushy]

225/45's are closer to 215/50 than 225/50 mate. The profile (45 or 50) isn't the actual depth of the profile but a % to the width, 20 a profile of 45 is basically the same on a 225 as a 50 is on a 215. A 50 profile on a 225 would be way out.

[nutron]

The speedo is normally about 5% out, so putting on 225/50 R17 will bring you closer to a correct speed. I know this because I have them on the front of mine and a GPS data logger (Performance Box) to give an accurate speed reading. I tried 225/55 R17 on the front but it rubbed on the internal plastic wheel arch on full lock (I do have 15mm lowering on the front, about the same as an SRI I believe).

[Derek Mc]

215/50 x 17 on mine read about 1mph fast, to keep the same rolling radius the exact same the size would be 235.45 x 17 but these are not that happy on a 7j x 17 rim width, preferring 7.5 or 8 x 17.

I stuck with the 215/50 for looks sake as I felt the arch gap especially in front with 225/s didn't look right and I am not going down the route of coil-overs etc etc, so I sought out excellent value 215/50's plus the oem size gives better economy wider tyres with lower profiles have increased rolling resistance too.

[nutron]

I think you need a more accurate GPS speedo, I've driven half a dozen Vectra Cs and not one of them were even close to 1% accuracy.

[Hideous]

could it fail an MOT if the overall diameter is larger than OE? quite possibly if they notice...
try this to see how different tyres compare to the OE: -
http://www.miata.net/garage/tirecalc.html

[peadar]

i have 235/45 on omega rims they read 2 mph lower than my clock im going to change them to 215/50 because the 235,s pull the car on every line/track on the road (country roads)

[lee gsi]

If you know someone with TECH2, VauxCom or Op-Com you can select what tyres are fitted so the speedo reads correctly.