Depends which vehicle ...
But mostly no, the (albeit small) difference in circumference will give a small difference in actual speed.
Work out the %age difference and decide whether it's worth it. When i went to larger (31") tyres it made my speedo quite accurate where it used to overread with standard size tyres. I now know that at an indicated 70 I am doing 70/71 whereas standard tyres at an indicated 70 meant my actual speed was about 65 (GPS readings)
But mostly no, the (albeit small) difference in circumference will give a small difference in actual speed.
Work out the %age difference and decide whether it's worth it. When i went to larger (31") tyres it made my speedo quite accurate where it used to overread with standard size tyres. I now know that at an indicated 70 I am doing 70/71 whereas standard tyres at an indicated 70 meant my actual speed was about 65 (GPS readings)
thebiglad
Well-Known Member
Hi there, I'm not quite sure what you mean? Changing the wheels (for same diam alternatives) does not normally dictate a change in tyre size?
If you change the rolling circumference of your tyre it will impact on your speed reading by 3.5%. But don't worry as the TD5 speedo reads over by approx 5%, so you would end up with a more-than-normally accurate speedo.
50 pence
New Member
You,ll be increasing your rolling radius by around 3 %. So your speedo will be slightly more accurate. But you will record lass miles, so mpg would seem to be affected.
A lot depends on the make of tyre.
My old 255/65/16 Grabber UHP,s had a 2160mm circumference, and my new 255/70/16 BFG AT,s had a 2230mm circumference. 70mm is 3% difference.
The tyre size calculators are only mathmatical figures, and not at all representative of real tyre sizes. They are ok to give you an idea about % differences.
Del.
A lot depends on the make of tyre.
My old 255/65/16 Grabber UHP,s had a 2160mm circumference, and my new 255/70/16 BFG AT,s had a 2230mm circumference. 70mm is 3% difference.
The tyre size calculators are only mathmatical figures, and not at all representative of real tyre sizes. They are ok to give you an idea about % differences.
Del.
tested it on one of them signs then have on the road side Seems strange that you're moving to alloys and upping the profile of the tyres.
I thought alloys and "low profile" went together more.
Also, increasing the profile from 55 to 60 seems a pretty pointless change and I'm surprised you're obliged to change the tyres at all. Is this due to the stockist only have 60's in stock? Why not just put the old tyres on the new rims? Am I missing something? Do the new alloys really _need_ higher profile tyres?
I thought alloys and "low profile" went together more.
Also, increasing the profile from 55 to 60 seems a pretty pointless change and I'm surprised you're obliged to change the tyres at all. Is this due to the stockist only have 60's in stock? Why not just put the old tyres on the new rims? Am I missing something? Do the new alloys really _need_ higher profile tyres?
The 'height' (55 or 60 in this thread) is actually called the "aspect ratio" or "profile" and is a percentage of the width.
Getting wider tyres but keeping the profile the same yields taller wheels.
But I'm sure you already knew that
