Lot of people are putting different wheel sizes on their car for several reasons. We all now that bigger/smaller wheels will effect our speedometer. Does it mean that size of wheels will effect mileage as well as speedo? For example 155/70/13 to 195/55/15 would make a -8.11% speedo error. If we would put this wheels on car from new after 150000 car really done 137835? cheers
Speedo/Mileage error theory
- Thread starter mckenziecz
- Start date
pollyp
Club Member
what's on here? a question?
last time i had 155/70/13 (547mm total diameter) the speedo read way too high. at 70mph gps speed it read 75-76mph. currently i'm on 195/50/15 (576mm total diameter) and the speedo is bang on target.
speedometer and odometer are both connected so yeah changing tyre diameter affects the speed reading and odometer as well as gearing, economy, handling, noise, comfort, wheel durability etc
last time i had 155/70/13 (547mm total diameter) the speedo read way too high. at 70mph gps speed it read 75-76mph. currently i'm on 195/50/15 (576mm total diameter) and the speedo is bang on target.
speedometer and odometer are both connected so yeah changing tyre diameter affects the speed reading and odometer as well as gearing, economy, handling, noise, comfort, wheel durability etc
superls
K10 Tuner
this will be set from factory to be accurate with the standard size wheels and tyres, the odometer is a direct gered drive off the gearbox whereas the speedometer isnt, thats where the inaccuracies occur.
shaun nice theory, but id rather buy a car with 100k miles on with the standard wheels/tyres than one which should have 14inch on but has been fitted with 17 inch (typical corsa/saxo/etc) due to the extra loadings on wheel bearings, gearbox, clutch engine etc.
shaun nice theory, but id rather buy a car with 100k miles on with the standard wheels/tyres than one which should have 14inch on but has been fitted with 17 inch (typical corsa/saxo/etc) due to the extra loadings on wheel bearings, gearbox, clutch engine etc.
OP
OP
thanks for replies, my current "project" has got -16.13% error! that would make the 16000 "younger" in 100000 miles by my theory. Are all the cars running from gearbox then?
Shaun
***StaGGeRed***
OP
OP
yep, only proper stuffplank suspension
I use this http://www.carbibles.com/tyre_bible_pg4.html to calculate the difference @ 70mph
scroll down and you can put in before and after wheel/tyre size (Y)
scroll down and you can put in before and after wheel/tyre size (Y)
