Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: rbowman Newsgroups: comp.os.linux.misc,alt.comp.os.windows-11 Subject: Re: Double booting Date: 9 Dec 2025 20:20:46 GMT Lines: 52 Message-ID: References: <106mke5$1di32$1@dont-email.me> <10gislv$sv5d$1@dont-email.me> <10gjk9c$158ec$1@dont-email.me> <10gjtk2$18glc$1@dont-email.me> <10gjueh$1934g$3@dont-email.me> <10gmhif$273r2$8@dont-email.me> <10gp6kv$37llv$7@dont-email.me> <10guib0$1ai5r$1@dont-email.me> <10h15ek$2cgcb$1@dont-email.me> <10h6jb8$5cd2$1@dont-email.me> <10h8se2$nshd$6@dont-email.me> <10h92s4$pu3t$1@dont-email.me> <10h9air$s0tc$3@dont-email.me> <1ipl0mxq5b.ln2@Telcontar.valinor> <10h9s9u$11cvm$3@dont-email.me> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Trace: individual.net ddNWpBQGH7IelC1nvsGQiAwiKZYq34cRpEcTQDQfyngnD5Oyym Cancel-Lock: sha1:7qctx7cGKcjhCKBvqHoBNtMnunI= sha256:wojtln/xMPHPA8lajBtJYhV0GBsdjDSJSCHSsBryTPA= User-Agent: Pan/0.162 (Pokrosvk) Xref: csiph.com comp.os.linux.misc:78589 alt.comp.os.windows-11:28112 On Tue, 9 Dec 2025 19:11:58 +0000, The Natural Philosopher wrote: > On 09/12/2025 14:50, Carlos E.R. wrote: >> On 2025-12-09 15:09, The Natural Philosopher wrote: >>> On 09/12/2025 11:57, Daniel70 wrote: >>>> On 9/12/2025 9:08 pm, The Natural Philosopher wrote: >>>>> On 08/12/2025 22:39, rbowman wrote: >>>>>> On Tue, 9 Dec 2025 00:20:38 +1100, Daniel70 wrote: >>>>>> >>>>>>> I usually put it down to my Tyres being under-inflated, so their >>>>>>> diameter is less so it takes more revolutions of the tyre to cover >>>>>>> a specified distance. >>>>>> >>>>>> I don't think under inflation would change the diameter enough to >>>>>> throw the speed off that much. In my case the diameter of the 14" >>>>>> wheels is noticeably less than the 15". I see that in the spring >>>>>> when I'm going back to the 15". If I jack the car up enough so the >>>>>> 14" leaves the ground and I can remove it sometimes I have to jack >>>>>> a little more to get the 15" on. >>>>>> >>>>> There is no such thing as diameter on a tyre. It isn't circular. >>>>> Might as well ask yourself 'what is the diameter of a tank track' >>>>> >>>>> What counts is circumference and the tyre is elastic enough to >>>>> expand a little under high pressure. >>>> >>>> .... and that pressure would get higher due to usage heating the >>>> tyre. >>>> >>>>> And to wear a little lower. >>>> >>>> ... which would reduce the tyres diameter, so decreasing the Ground >>>> speed. >>> >>> THE TYRE HAS NO DIAMETER., It is not circular. >> >> It doesn't matter. We can calculate it. >> > No you cannot. > Any more than you can calculate the 'diameter' of a tank tread. > You might choose to evaluate (circumference over pi), but that is just a > number that has no meaning in this context. There is no physical > dimension that corresponds to it The rolling diameter is no more or less inaccurate than the rolling circumference. Are you familiar with the process of calibrating a bicycle speedometer? You mark the tire and ride a specific number of revolutions, measuring the distance covered. That gives you the rolling circumference which is not necessarily the same circumference of the unladen tire. But have it your way, as you will.