SE 15" Tyres - Alternative Sizes

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SE 15" Tyres - Alternative Sizes

Postby elaverick » Tue 04.12.2018, 20:58

Has anyone tried running with 195/60 R15s?
A friend who works in the tyre industry was enlightening me about the way the sizes are calculated and pointed out that 195/60's are only 1.38% (8.5mm) wider than the 205/50 R15s that are recommended. He says that they should fit without causing too many problems, but advised me to ask here in case anyone had actually tried them to see if there were any issues with rubbing or other unexpected fit issues.
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Re: SE 15" Tyres - Alternative Sizes

Postby Giniw » Tue 04.12.2018, 21:04

195*.6=117
205*.5=102.5
diff=117-102.5=14.5mm if I am not wrong so I am not sure where he finds the difference is 8.5mm?

Anyway, I can't see why you would put 195 60 tyres on an Elan, I certainly would not want that on my car.
It would be a pity to ruin the handling and looks of a great car to possibly save a couple of pounds.
But that is just my opinion %)
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Re: SE 15" Tyres - Alternative Sizes

Postby par » Tue 04.12.2018, 21:31

I think you guys are getting tyre width and sidewall height mixed up.

The width of the tyres are as those stated i.e. a 195 tyre is 195mm wide and a 205 tyre is 205mm wide.

The 50 and 60 dimension referred to is the side wall size as a percentage of the width so for a 205/50 tyre the sidewall is 50% of 205 = 102.5mm and a 195/60 tyre the sidewall is 60% of 195 = 117mm.

Adding the wheel diameter into the mix allows for a side by side comparison of overall diameter which involves a quaint mix of imperial and metric units:

205/50 x 16" = 102.5 + 102.5 + (16 x 25.4) = 611.4mm

195/60 x 15" = 117 + 117 + (15 x 25.4) = 615mm

So this means this very little difference in the diameters of the 2 packages before factoring any tyre wear but the 195 option will be a narrower tyre by 10mm.

HTH :D
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Re: SE 15" Tyres - Alternative Sizes

Postby Giniw » Tue 04.12.2018, 21:52

par wrote:I think you guys are getting tyre width and sidewall height mixed up.
Mmm no I was referring to the sidewall size too?

Adding the wheel diameter into the mix allows for a side by side comparison of overall diameter which involves a quaint mix of imperial and metric units:
205/50 x 16" = 102.5 + 102.5 + (16 x 25.4) = 611.4mm
195/60 x 15" = 117 + 117 + (15 x 25.4) = 615mm
So this means this very little difference in the diameters of the 2 packages before factoring any tyre wear but the 195 option will be a narrower tyre by 10mm.
Why do you use 16" wheels in the first expression? Unless I read something too fast it's both the original OZ SE sizes, ie 15 inches rims — so 14.5*2=29mm difference in diameter.
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Re: SE 15" Tyres - Alternative Sizes

Postby elaverick » Tue 04.12.2018, 21:56

Giniw wrote:diff=117-102.5=14.5mm if I am not wrong so I am not sure where he finds the difference is 8.5mm?


It was going off the tool here - https://www.oponeo.co.uk/advice-and-tip ... veTireTool

And yeah it should be for 15" not the Federal/S2 16" ones

(Edit)

Having compared again it would actually need to be the 195/55 15's I think my friend had plugged in our standard tyres as 205/55 15's rather than 205 50 15s
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Re: SE 15" Tyres - Alternative Sizes

Postby par » Tue 04.12.2018, 22:06

Giniw wrote:
par wrote:I think you guys are getting tyre width and sidewall height mixed up.
Mmm no I was referring to the sidewall size too?

Adding the wheel diameter into the mix allows for a side by side comparison of overall diameter which involves a quaint mix of imperial and metric units:
205/50 x 16" = 102.5 + 102.5 + (16 x 25.4) = 611.4mm
195/60 x 15" = 117 + 117 + (15 x 25.4) = 615mm
So this means this very little difference in the diameters of the 2 packages before factoring any tyre wear but the 195 option will be a narrower tyre by 10mm.
Why do you use 16" wheels in the first expression? Unless I read something too fast it's both the original OZ SE sizes, ie 15 inches rims — so 14.5*2=29mm difference in diameter.


Sorry I misread the original post and thought it said 205/50 r16, however the OP was comparing width and the calculations being used are for sidewall height and comparing diameters.
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