Well, hardly a stitch up, just idiocy really.

But, popped into some backstreet tyre fitters this morning and got a part-worn on the front near-side…

Yes, I can hear the gasps of horror regarding part-worn and not replacing both ends of the axle etc etc. But tbh, I treat my car like a crap tool. It gets ragged round a city every day and it gets the bare minimum to make it work/pass its test. It’s extreme bangernomics. I do all my own servicing, and It’s probably worth £300 on a good day.

Anyway, for the last week or so I’ve noticed the steering wheel wobbling from side to side and the car always pulling to the right. So this morning, take a look, and there’s a massive bulge on the nearside tyre. So fearing a blowout I take it in and get the bulging tyre replaced.

Anyway, all good, or so I thought… but just had a look and they’ve put on the wrong size. It’s a 145 rather than a 155. So ten MM less width on the tread. Other bits are right, the diameter and the other one. So the question is: Can I crack on? I’d rather not go back if I can help it because I can’t be bothered. The car feels alright, better in fact, but is it ‘excessively’ dangerous? And most importantly, will it pass an MOT?

Mot fail.

One tyre is of a different nominal size or aspect ratio to any other on the same axle

Im a freindly mot tester btw

Fair enough. I’ll take it back tomorrow.

Thanks.

Also remember that the width (155) is a measurement whilst the sidewall height (AKA Section i.e. 55) is a percentage of the width, so if the width is wrong, the total wheel diameter, despite being the same number as the other wheel, is also wrong.

Interesting. I didn’t know that. Thanks.

What are the implications of this? Am I dicing with death even driving it back? Or can I forget about it until MOT time (6 months) then sort it? Will it balls the suspension/ steering gear up?

It will be ok to drive, think about space saver spares. However I’d take it back and get is sorted. You’ve paid for something and they’ve not given you the correct or legal something.

Have an accident and test your insurance 💡

1. It invalidates your insurance,
2. It could mess up your ABS as the wheels are turning at different speeds,
3. Dependent upon where you Speedo sensor(s) is/are, you could be over reading your speed.

1. It invalidates your insurance

Wouldn’t have thought so

Perfectly fine driving on a space saver spare, so not sure why this would be any different.

Perfectly fine driving on a space saver spare, so not sure why this would be any different.

1. It’s a temporary tyre, designed and specified by the manufacturer of the vehicle as a means to get you to a garage for a repair.

2. Permanently fitting a non manufacturer approved size of tyre counts as a modification and needs approved by your insurer. Fitting tyres of different sizes on the same axle is an MOT failure and thus an offence.

2. Permanently fitting a non manufacturer approved size

I was working on the assumption that this was the plan…..

Fair enough. I’ll take it back tomorrow.
Thanks.