Modern Tyres & Under Gearing !
Posted: Mon Feb 10, 2020 11:00 am
Hi All ,
I don`t know who else has checked this ... but the modern 80 profile tyre is noticably shorter in height ( Rolling Radius/Circumference ) than the original spec` tyres of the same size , that were fitted to the cars in period .... despite me being told by garages that they are the same ...
I know there are "Manufacturing Tolerances" ... but when we physically stood an inflated , original Dunlop spec` tyre against a modern equivalent ... the difference was obvious ... which naturally causes even more engine rev`s out on the open road ...
This was even more evident last week ... when a good friend , had a lovely new set of Super Dougal`s ( of Highly Recommended Longstone Tyres ) original spec` Pirelli Cinturato 145`s fitted to his S3 Elan ... & the new period 145`s again , were even taller than the modern 155/80`s he had just taken off !
This is good news for those wanting to get the rev`s down ( particularly with the 4 speed box ) on the S1-S3`s ... & I suspect the new mega Michelin period 155 or 165 XAS will have the same effect for the later cars !
I have got around the problem on my S4 ( which has adjustable suspension ) , by simply fitting a 165/80 modern classic tyre on the rear .... which according to a tyre calculator , makes it virtually identical to the original gearing of a period 155 : ) !
This makes my Elan even more pleasurable to drive on any journey , even with just a 4 speed box ... just like they did back in the day !
Paul.
I don`t know who else has checked this ... but the modern 80 profile tyre is noticably shorter in height ( Rolling Radius/Circumference ) than the original spec` tyres of the same size , that were fitted to the cars in period .... despite me being told by garages that they are the same ...
I know there are "Manufacturing Tolerances" ... but when we physically stood an inflated , original Dunlop spec` tyre against a modern equivalent ... the difference was obvious ... which naturally causes even more engine rev`s out on the open road ...
This was even more evident last week ... when a good friend , had a lovely new set of Super Dougal`s ( of Highly Recommended Longstone Tyres ) original spec` Pirelli Cinturato 145`s fitted to his S3 Elan ... & the new period 145`s again , were even taller than the modern 155/80`s he had just taken off !
This is good news for those wanting to get the rev`s down ( particularly with the 4 speed box ) on the S1-S3`s ... & I suspect the new mega Michelin period 155 or 165 XAS will have the same effect for the later cars !
I have got around the problem on my S4 ( which has adjustable suspension ) , by simply fitting a 165/80 modern classic tyre on the rear .... which according to a tyre calculator , makes it virtually identical to the original gearing of a period 155 : ) !
This makes my Elan even more pleasurable to drive on any journey , even with just a 4 speed box ... just like they did back in the day !
Paul.