Tyre size differences

Adam

Adam

Adam

Soldato
Joined
18 Oct 2002
Posts
9,251
My original focus alloys were 195/60/15 and are dangerously low so I ordered some 195/50/15 as these are more readily available, more choice, better price etc.

Now as i'm at work I thought i'd trust my mum to get the tyres fitted for me today (big mistake :o). She left the tyre place having been told that the guy can't fit them as the tyres are a different size (well yeah duh) and proceeded to compare the tyres I gave him to the tyres on the car concluding that "the newer ones are smaller".

I have checked an online tyre calculator and the difference between the tyres will be -6.34% which I personally think is acceptable. What reasons would he have for refusing to fit the tyres? The rear ones will still be the same as the originals if this makes a difference (195/60/15).

Cheers!
 
So he was right not to fit them? Surely my speedo will just be out by 6% unless there are other problems I am not aware of?
 
You can take off 195/60's and put 17 inch aftermarket wheels with 205/45's and it will pass an MOT so i cant see what the problem would be ?!
 
That would only be a difference of 0.16% though. It looks as if I may have made a mistake and as BenST says the safe difference appears to be 2.5% oops.

Just presumed this wouldn't be a problem due to changing from 15" to 17" in the past but it appears that the tread width compensates for the change in profile.
 
I called the place online that I bought the tyres from and they suggested the tolerance was 1% so it seems like 6% is massive.

Looks like I will have to sell them privately myself and swallow the loss.

Can anyone suggest any reason other than the speedo why they may be dangerous? (Don't worry not going to fit them :p)
 
1: take them some were else to have them fitted
2: if your putting different size tyres on change all 4 not just 2
3: I bet you £100 that with stock tyres on your clocks will under read (do you think they [the manufacturer] change the clocks on the different car’s they make when they leave the factory
4: it is an offence for the manufacturer to supply you with a car that over reads your speed
5: stop been a gimp and get them put on
6: the customer is ALL WAYS RIGHT :)

7: as long as the tyres on the same axel are the same there is no problem
I.e. the front 2 are the same as each other and the back 2 are the same as each other there is no problem.

Why are you lot making such a big deal out of nothing?
 
Last edited:
whitecrook said:
Indeed - I don't see a problem, but I'd change all 4 to the same. 2 could be 'interesting'.
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So the rear of the car will be a few mm higher than the front. I can't see it making much difference TBH, people probably do more when they lower them.
 
Different size front and rear can throw TCS systems out. i know it did on mine and my Missus's Mondeos when we got rears on both and they stuck 55's instead of 50's on by accident. But i'm guessing a focus doesn't have TCS? so shouldn't be a problem.
 
Normally no, but mine has a load of factory fitted options including rear disk brakes, ABS, TC etc etc.

I have decided just to sell them at a loss. Quite annoying but its my fault for not checking. Will loose about £15 so not the end of the world.
 
Adam said:
Normally no, but mine has a load of factory fitted options including rear disk brakes, ABS, TC etc etc.

I have decided just to sell them at a loss. Quite annoying but its my fault for not checking. Will loose about £15 so not the end of the world.
Click to expand...

just get 2 more so you have a full set and there will be no probs
 
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