I have been doing some arithmetic:
If a nearly bald tyre has a diameter of 1200mm then it has a circumference of 3769.91mm
A new tyre with 9mm more tread has a diameter of 1218mm and a circumference of 3826.46
The bald tyre would rotate 265.26 times in a kilometre and the new tyre 261.34 times that is a 1.5% difference.
So if the speed was set at 90kph with the bald tyre, then fitting new tyres would mean that it would actually be doing 91.35kph when the speedo showed 90.
However; since the new tyre would slow acceleration, then journey times would only be improved by 1% at most.
This means that a journey that took 2 hours on bald tyres would take 2 minutes less on new tyres at best.
funnyfut:
Ah but if you are running on bald tyres you would lose time when mr plod pulled you and you had to get them changed
And everyone else would loose time if they suffered a ‘blow out’…
Heard on local radio today truck suffered a blow out on the A1 near Greetham turning (South of Colsterworth), road blocked for 1 -2 hours que’s back past colsterworth!!!
I had the unfortunate task of waiting for a space to enter the A1 this morning from a service station further down from the accident…as i jumped in my truck i suddenly saw all the traffic thundering by and thought i would be their till xmas…
UPDATE: well i’m still waiting for a gap in traffic now so looking that way at the minute…not sure how much longer clutch can take me holding the biting point like this…plus i’ve run out of liquid refreshment and anything edible in the cab…curtains arn’t that tasty
This means that a journey that took 2 hours on bald tyres would take 2 minutes less on new tyres at best.
PHYSICS - if the speed is constant then the journey time will be the same no matter how big or small the tyres are.
The number of rotations, depending on size, will be different though.
Doesn’t apply here ROG due to limiter. Both tyres will be limited to the same revolutions per minute, but due to larger circumference will carry you further per turn as Santa says.
Don’t think you’d notice the loss in acceleration Santa
Doesn’t apply here ROG due to limiter. Both tyres will be limited to the same revolutions per minute, but due to larger circumference will carry you further per turn as Santa says
Thanks - beat me to it
Don’t think you’d notice the loss in acceleration Santa
I think there’s more than 18mm difference between a balding already re-cut tyre and new one, more like a good inch at a guess, maybe more.
Had that myself once, not deliberate just coincidence, as I has very little influence over it. My truck at the time needed recalibrating due to faulty sender. It was done on balding already re-cut tyres. Then a couple of months later needed new tyres - big difference.
think there’s more than 18mm difference between a balding already re-cut tyre and new one, more like a good inch at a guess, maybe more
I researched this as I didn’t know. 9mm is typical of a modern truck tyre. In my calculation i said that would add 18mm to the diameter but, since 1mm is the legal minimum, it would really add 16mm.
think there’s more than 18mm difference between a balding already re-cut tyre and new one, more like a good inch at a guess, maybe more
I researched this as I didn’t know. 9mm is typical of a modern truck tyre. In my calculation i said that would add 18mm to the diameter but, since 1mm is the legal minimum, it would really add 16mm.
How did you research it ? On a brand new tyre how deep is the tread ? Got to be at least 9mm and then it can be re-grooved say 3 or 4mm
