DaveinOlyWA
Well-known member
watchdoc said:DaveinOlyWA said:We are not looking at "unsprung weight" We need a rotational mass calculation to quantify the difference. An 8 lb difference is significant. The wheel size to efficiency effect I first discovered while perusing the 2010 Prius during its reveal at the 2009 Detroit Auto show. While looking the car over, we found the engineer's notebook in the car and started thumbing thru it. As you would expect; most of it was unreadable but the page stating a the mpg differences between tire sizes was unmistakable.
F = m*v^2/r
Summarize your point for me please. So you're saying skinnier tires has more effect than unsprung weight?
The combo I'm looking at would be greater than 10lbs per corner lighter but retain the stock 215 tire size.
This article seems to indicate that tire width is much less important than rolling resistance and wheel size.
https://www.greencarreports.com/new...d-wheel-choice-affects-electric-vehicle-range
So here's my question. assuming everything else is the same (same tire, same width, same total diameter, same total weight) would a 16" wheel and tire combo be more efficient than a 17" wheel and tire combo? If so, why???
Question; its the weight. smaller wheel diameter simply means taller tire so overall diameter would be the same or very close to it. The reality is driving on low profile tires is well... I don't know. I don't know why people think they are cooler, look better or anything else for that matter.
The shorter sidewall means less flex so more beefing to be able to handle the degrading American infrastructure.
Looking at the formula and determine what changes. In your question, only the mass changes. If the wheel size actually did control the diameter, then yeah, efficiency would skyrocket but the difference is pretty small but a 25% difference in weight is significant.
As far as the article, its right only in that more efficiency is not a one shot deal. Its a lot of stuff; LRR tires, max safe tire pressure, smaller wheels which are almost always lighter than tires unless you get the super expensive alloys which I know some that have and they don't seem to hold up well over time but never really got many details on it simply because it wasn't possible to get a favorable ROI.
You want efficiency; use constant power, minimize sprints and regen and never use braking if possible. Now all that is a challenge but every second you make it is a bump on the range and also good for the battery as well. We all want the gentle life and your pack is no different.