Bigger tyres performance/economy ?

[Junosi]

Hi all, I'm new to the P38 fraternity having picked up my new 1995 HSE last night :) Owned a disco for many years and finally got around to upgrading.

Anyways I'm going to replace all the tyres, probably with BFG at's - but I'm having trouble deciding on what size to get. I do a fair amount of offroading and ground clearance was always a consideration in my disco with standard size wheels so been thinking of upsizing a little on the p38.

My concern is about the performance hit of larger diameter wheels - how noticeable is it ? Lots of info on the web about fitting larger wheels but finding it hard to find any info about acceleration loss or cruising at 110kmh, overtaking etc etc - with bigger wheels fitted.

Thanks for any advice in advance.

[Scouse]

How big do you want to go?

Standard is 255/65/16. BFG is available in 255/70/16.
After that, there's 245/75/16.

Bigger still will require mods.

[Junosi]

I was thinking 255/70 (3.5% bigger) or 245/75 (5% bigger)

[Scouse]

I'm running 255/60/18 (same OD as 255/70/16) & besides putting the speedo spot on, I can't notice any difference.

[PaulP38a]

I run a little larger again (with mods as Scouse correctly states)...255/85R16 and 265/60R18... and don't have a problem with power, cruising or overtaking... although I do need to keep an eye on the GPS due to the 5%-15% speedo error.

Cheers, Paul.