Welcome to this week’s casual kōrero thread!
This post will be pinned in this community so you can always find it, and will stay for about a week until replaced by the next one.
It’s for talking about anything that might not justify a full post. For example:
- Something interesting that happened to you
- Something humourous that happened to you
- Something frustrating that happened to you
- A quick question
- A request for recommendations
- Pictures of your pet
- A picture of a cloud that kind of looks like an elephant
- Anything else, there are no rules (except the rule)
So how’s it going?
Ooh that’s interesting. I have seen this in almost every car I’ve ever driven past one of those things. There’s actually one car that I remember borrowing one time that stands out in my mind as it matched the speed sign thing and that was unusual enough to still remember it years later.
I just assumed that since the speed is read internally (gear box or something?), as the mm if rubber come off the tire the speedo would over read more and more.
Maybe? Surely it’s quite a few mm to get 3km/h over though?
Sounds probably like I need to learn math again… Eww!
Actually, surely tires aren’t all the same size? Ours are recently installed and the measured difference hasn’t changed.
Just found this reddit post. A comment says:
I think 0.6mm isn’t enough, but we can expand on that. A search shows a new tyre might have 8-9mm of tread. And legal minimum is 1.5mm, so that’s 6.5mm or so difference, or about 10x the test above. Still, that would only make a difference of about 1km/h in the reading over the life of the tyre.
So seems 3km/h over is not explained by tyres. I guess F1 car tyres are smaller, but I’d think the impact would be smaller on larger tyres.
I thought you had to get the exact same sized tyres, because they had to fit the wheel.
Reddit seems to think it’s calibrated to the factory installed wheels.