18" and 19" on same axle?? Errors popping up.

[Paddy]

I dropped off an 18" rim to get refurb'd on Wednesday and instead of giving me a lend of an 18" they gave me a 19" rim because they already loaned out one other 19" and they didn't want to be short 2 sets of rims just because there was one of each set loaned out.

So anyway, the road noise from the 19" is dreadful and now I'm getting flat tyre alarms and DSC failure alarms coming up. Could it be that the different pressure and rolling diameter compared to the 18" on the same axle is causing the sensors to throw up these errors?

I am really hoping this is the case and when I get my own 18" back, the issue will be gone! Any opinions??

Thanks!

[JohnC]

The rolling diameter shouldn't be different if the correct size tyre was fitted.

You could put a 20" wheel on with the skinniest of tyres to get the same diameter. Or you could put a 14" wheel on with a beefy side wall to match the diameter.

The road noise is probably because there is less tyre to absorb the noise.

BUT in your case they probably didn't match rolling diameter so you are probably right.

[JohnH]

Just don't go too quick with mis matched sizes on

[Paddy]

It's very difficult to drive with the other wheel on, steering feels heavy and sluggish, and there's vibration there all the time, worsens when braking. The 19" beside an 18" is close in diameter but the 19" is slightly larger diameter. It's the only thing I can think of!

I've been keeping her about 80kph normally and no more than 100kph on motorways but it's definitely noticeably not driving/handling right! I'm praying it,s because the different size rim and tyre. I was meant to get my own rim back yesterday but they hadn't it finished and I'm working the weekend so need the car!

[HealyC]

What's the tyres sizes on the 18 and 19? As John said don't go too quick if it's on the back. If it's an option put the 19 on the front

[Paddy]

Cheers, I can't remember off hand what the tyre sizes are (I'll have a search on here for my own as I ordered through alloywheels.ie), but both 18" and 19" are on the front as it's the front passenger side in getting refurb'd.

[Paddy]

So mine are 225/40R18 but can't get out to the car yet to check what the 19" is. Would there be any other cause of the errors would anyone know?

[Peter-E36]

I wouldn't be panicking about any flat tyre/dsc warnings until you get the your normal wheel back

[Paddy]

I wouldn't be panicking about any flat tyre/dsc warnings until you get the your normal wheel back

Fingers crossed Peter. Just seems weird that it's happening after the wheel change! As soon as my own rim is back I'll be resetting anything I can and hope and pray from there.

[Paddy]

Bit of reading online and looks like the steering angle sensor could be affected by the different size wheel and throwing a wobbly!? Also alignment can throw it out maybe.