Which tyre profile size.

[SpitfireGeorge]

Hi Guys,

I have purchased some new replica minilite wheels, 5J x 13, for my Spitfire Mk3. I intend to fit 165 x 13 tyres but I am not sure which profile size to use. I want the speedo to be accurate so should I use 70, 85 or 90 profile tyres? There seems to be plenty of 70s about.

Cheers,

Brett

 

[dave.vitesse]

The original size was 155x80x13. 175x70x13 has the same rolling radius as the original. 165x80x13 will give a slightly slow, under read, speedo. 165x70x13 will give a sightly fast, over read, speedo.

As standard the speedo's tend to over read 165x80x13 may be not too slow.

If the car has been lowered then 175x70x13 or 165x80x13 may have clearance problems.

Dave

[Clive]

mk3 spit.... I would say "probably" 165/70 if you must have 165 width. Partly depends on the wheel offset

However, nothing wrong with 155/80, the original size where radials were fitted. Plus they cope a little better with the swing axle "habits".

Whatever you buy, please buy decent quality.....well worth the extra even if you are unlikely to wear them out in 7 years.

Any of the tyres you suggest will only be out by a maximum of a couple of mph even at 70.

 

(Edit. If you have the new springs on the front of the car that sit it a bit higher than std, low profile tyres can make it look worse! ie the gap between tyre and wheelarch gets huge even if changing by 8-10mm diameter (which is less than the difference between a brand new and worn-to-the-limit tyre)

[SpitfireGeorge]

 

Thanks for your help guys.