I have a Luego with 195/45/15 rear tyres and the gearing is to low, ie I end up doing 3000 rpm in top at 70 and I would like to be doing much less. If I change to 195/55/ 15 would it make much difference?

http://www.tyresave.co.uk/tyresize.html

7% difference of 3000, so not a lot really

[Edited on 30/5/10 by ReMan]

7.2% difference in rolling circumference will give you 2780 rpm at 70 with the bigger tyres.

Edit: Too slow

[Edited on 30/5/10 by matt_claydon]

its a 7% difference

at 70 you will be doing 74.9mph

2790rpm down from 3000rpm

I just changed my rears from 245/35/17 to 245/40/17 and although the difference is only small, it made quite a difference to my revs - 1st gear becomes a useable gear and 5th is now almost an overdrive.

7% might not be much, but its as much as changing the diff ratio by one step

eg. 3.62 -> 3.38 = +7%

quote:

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Originally posted by Steve Lovelock
I have a Luego with 195/45/15 rear tyres and the gearing is to low, ie I end up doing 3000 rpm in top at 70 and I would like to be doing much less.

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Also be aware that if your front wings are close to the tyres now then they may be touching when you go up a profile. DON'T ASK

Also note that 195/55R15 is a significantly more expensive tyre size than 195/50R15.

[Edited on 30/5/10 by MikeRJ]