Newbie tyre advice 155 80 R13 or 175 70 R13

[Andy P]

Hi new to the forum and to spitfire ownership. I've just bought a Mark IV 72 Spitfire on standard 4.5 rims, suspension is all factory spec apart from addition of Gaz adjustable shocks. Its currently fitted with 23 year old 175 70 tyres, limited wear but given the age I need to replace these.

Should I go for the original spec 155's or stick with the wider 175's?

I like the wider look of the 175's but I wonder if going back to 155's would give a better overall feel / performance? I've been surprised at the steering weight a low speeds on the 175's but maybe that's just what its like going back to an older car without power steering and perhaps typical of spitfires. I also gather that the contact patch on a wider tyre is elongated rather than increased for the same tyre pressure, so in fact extra grip maybe a misnomer particularly with a 'normal' driving style. 

Also any recommendations on brands? Seem to be some that offer a 'classic' look / tread / performance etc but again I wonder if this is really something I would notice? 

thanks

 

[Pete Lewis]

having had 175 on the old 4.5jvitesse i dont recomemend them fine on 5.5 rims  there is just too but balloon 

sidewalls with a wide tyre on a narrow rim   

so if it was me i am sure you will find 155 more stable on your 4..5J rims 

and going wide doesnt help the footprint on the tarmac unless you change the pressures or vehicle weight

so steering will lighten up  also 

Pete

[dougbgt6]

Also bear in mind that modern tyres are not the same as those fitted in 1972 and are best at a much higher pressure than the manual says. Manual says GT6 front 24, mine are 30. Even with standard tyres turning the steering wheel when stationary is a struggle for me, and I couldn't cope with fat tyres. Although, one of ours at East Berks has electric power steering on his Spitfire taken off a Japanese modern. 

I recall a number of threads on here about tyres, but can't find them due to my incompetence with the search facility, however a search on the interweb revels this:

 Replacement Tyre options for Spitfire 1500 - Running Gear - Club Triumph Ltd

 

Doug

Edited October 8 by dougbgt6

[Nigel Clark]

On standard rims definitely fit 155 tyres. As Pete says, the 175/70 is too fat on a standard rim and only suitable for wider rims. 

Nigel 

Edited October 8 by Nigel Clark
Typo

[GFL]

I'm going through a similar exercise at the moment, my cars currently fitted with 175/70 tyres on 4.5J Rims (Chrome wires)

These are too wide in my opinion for a 4.5J Rim, I'm going to swop them for the standard rims (Vitesse 4.5J) and then fit 155/80 Size Tyres

I've used Nexan and Uniroyal Rain-expert tyres on my previous classics and found these to be fine.

175/70 Tyres are best suited to 5J or 5.5J wide rims ideally and work well although there is no doubt the steering is a bit heavier with these fitted

Good Luck

Gary    

[Andy P]

Thanks all for the advice seems like a switch back to 155's is the consensus and will lighten the steering a little too.