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Active Member
Hello everyone,

After 2 years of absence I have returned to the RR ownership with a 1998 4.6 HSE :)

The immaculate 18 inch wheels are fitted with 285 55 18 Pirelli Scorpions.
These are really needing replaced and came across a nice set of 255 70 18.

Will these fit?

I must add that it has a spring conversion.
 
ⓡⓤⓓⓨ;3276567 said:
I know they are not the right size, but my question is - will they fit without rubbing?

Your car would be illegal. 285/55/18 60 mph indicated 62.7 mph true. 255/70/18 60 mph indicated 66.2 mph true. 255/55/18 60 indicated 60 true.
 
Your car would be illegal. 285/55/18 60 mph indicated 62.7 mph true. 255/70/18 60 mph indicated 66.2 mph true. 255/55/18 60 indicated 60 true.

Ah but the speedo is already inaccurate from factory
When mine wore 255/55/18 acording to my tom tom of the time when the speedo read 70mph I was at attualy doing 67mph! so a slightly bigger tire would bring it up to indicated speed
But physically yes they will fit
 
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Ah but the speedo is already inaccurate from factory
When mine wore 255/55/18 acording to my tom tom of the time when the speedo read 70mph I was at attualy doing 67mph! so a slightly bigger tire would bring it up to indicated speed
But physically yes they will fit
That's quite accurate by some standards, my Xtrail was acually doing 38Kmh at an indicated 50:eek:
The OP should take into account that those tyres are not homologated for the P38 and may invalidate his insurance if not delared.
 
Ah but the speedo is already inaccurate from factory
When mine wore 255/55/18 acording to my tom tom of the time when the speedo read 70mph I was at attualy doing 67mph! so a slightly bigger tire would bring it up to indicated speed
But physically yes they will fit

It isn't a linear response. Usually they overread at low speeds and underread at high speeds. Inflexion point usually around 47 mph so the old duffers can get as big a queue as possible behind them. :)
 
Ah but the speedo is already inaccurate from factory
When mine wore 255/55/18 acording to my tom tom of the time when the speedo read 70mph I was at attualy doing 67mph! so a slightly bigger tire would bring it up to indicated speed
But physically yes they will fit

Your Tom Tom is only accurate on a dead flat road with no raise or fall in gradient.
 
It isn't a linear response. Usually they overread at low speeds and underread at high speeds. Inflexion point usually around 47 mph so the old duffers can get as big a queue as possible behind them. :)

It is illegal for any vehicle manufactured in or after 2001 to be travelling faster than the speedometer indicates. Before that time the allowance was + or - 10% at 30 mph. That is why speed cameras are set not to flash until the speed limit +10% + 2 mph is exceeded.
 
Your Tom Tom is only accurate on a dead flat road with no raise or fall in gradient.
Not so anymore since selective availability was turned off. I've been checking GPS speed against fixed sign indicators and average over flying kilometers, my tablet is withing 1Kmh. Of course it does depend on the quality of the GPS recever.
 
That's quite accurate by some standards, my Xtrail was acually doing 38Kmh at an indicated 50:eek:
The OP should take into account that those tyres are not homologated for the P38 and may invalidate his insurance if not delared.

my very first p38 I had years & years ago was ex Staffordshire motorway police & the clocks were branded "RS" which were very accurate, & back to tyres its right size or nothing imo
 
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Not so anymore since selective availability was turned off. I've been checking GPS speed against fixed sign indicators and average over flying kilometers, my tablet is withing 1Kmh. Of course it does depend on the quality of the GPS recever.

Yes point to point on a flat surface very good. GPS does not do up and down hills well. Don't think the average GPS would have the calculating power to work out the difference in distance up or down hills between two fixed points. Although they do read altitude above mean sea level. It's a lot further in distance travelled from the top to the bottom of an hill than the two fixed points would be on the flat. Having said that it would need to be a pretty steep hill to make a lot of difference.:)
 

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