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Over inflate for better milage on road trips?
- Thread starter outdoordawg
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- Range Anxiety Road Trip
I would be worried about that being too much pressure for those tires, and contributing to a blowout or something. Thats just personal opinion, but tesla's already have their tires at the high end of the pressure spectrum, compared to many ICE vehicles.
I would think that over inflating a bit would be ok, but that sounds like too much to me. I think the maximum inflation on the OEM 20s is 50lbs, and they recommend inflating to 42. That sounds way to high to me, and the ride would also likely be uncomfortable and stiff.
maybe over inflating a little would be ok.. in my case, I might inflate from the recommended 42 to 44 or 45 but not farther than that.
EDIT: Let me also say that I am no where near an expert on this. Saying that, I personally wouldnt be comfortable running any tires at their max fill rating.
I would think that over inflating a bit would be ok, but that sounds like too much to me. I think the maximum inflation on the OEM 20s is 50lbs, and they recommend inflating to 42. That sounds way to high to me, and the ride would also likely be uncomfortable and stiff.
maybe over inflating a little would be ok.. in my case, I might inflate from the recommended 42 to 44 or 45 but not farther than that.
EDIT: Let me also say that I am no where near an expert on this. Saying that, I personally wouldnt be comfortable running any tires at their max fill rating.
Occhis
Member
45 PSI is already pretty high and if used regularly will result in uneven tire wear (the center wears faster than the edges). That said the tires will be fine running at 50 PSI and even slightly higher since they have factors of safety built in, but its probably not a great idea. I don't think you would see much improvement past 45 PSI, you will see more of a difference from using seat heaters with a lower cabin temp (or less AC in summer) than the tire pressure.
The biggest knob you can turn for efficiency is your speed. Keep in mind that aerodynamic drag increases exponentially with vehicle speed, so driving even 5 MPH slower can have a decent impact on your efficiency for a roadtrip. That said my preferred method of roadtripping is to drive fast, keep tires at comfortable pressures (~42) and stop to supercharge slightly more than i normally would.
Looking at the map, your biggest challenge will be from Amarillo to Trinidad, CO - i would definitely suggest driving slower on that portion of the trip specifically since its 225 miles and keep an eye on the range graph as you go to see if you need to go even slower (it will show projected battery at destination).
Enjoy the trip!
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At 47 to 48 PSI cold you will notice an improvement both in handling a range. i doubt you will notice the difference in ride...or if you do you will like it better.
JMHO. Not an expert.
JMHO. Not an expert.
CyberGus
Not Just a Member
Many "hyper-milers" successfully use overinflation as a tactic. However, if forced to make an emergency maneuver with significantly overinflated tires, you may regret having a smaller contact patch.
Candleflame
Active Member
yes, when I have to drive long distance with only AC charging available you get like 2-3% more range running the tires at 3.3 bar vs 3.1 bar. The effect diminishes at higher speeds but i usually drive 80-85 or so where it is definetely noticeable. With supercharging there isnt much point.
Handling and traction will decrease as the pressures goes up. For improved handling and traction you lower your tire pressure.
When you are on a trip you are generally loaded heavier than normal and driving faster than normal. Adjusting tire pressure higher is not over-inflation, it's adjusting tire pressures to be suitable for the driving conditions. What people forget, or don't know in the first place, is that every tire recommendation is based on a set of assumptions (speed, ambient temperature, load, road surface, what the engineers think the vehicle will normally be used for, and often (unfortunately) marketing input). Change any of the assumptions, and the recommendation should also change. The vehicle placard pressure is not a "one size fits all" number. The driver is supposed to examine the tires on occasion and determine if the pressures used are appropriate based on wear, and also think a bit about what the vehicle was designed for and if the driving conditions are matching that.
In general I agree with your statement...and yet, our model 3 handles better and is better glued to the road when we are running about 10 percent over recommended spec. Go figure.
YMMV.
Interesting. I would have guessed the opposite. I would think higher pressures would allow the tire sidewalls to deform less, so that handling would be tighter.
Traction, I would think goes down a little, since I would think the contact patch would be smaller, and generally traction goes up with a larger contact patch. On the other hand, the pounds per square inch of contact patch goes up, somewhat compensating for the smaller contact patch.
I wonder what the guys who track their cars do? Lower pressures at a drag strip for max traction, and higher pressures at Laguna Seca for max handling? Dunno.
The only thing I'd add, is when I feel like my car understeers too much when cornering, I add air to the fronts to increase traction. So, now I'm thoroughly confused.
The issue is that handling in this context is based on track and test track data which is easily garnered. Also it mostly relates to dry smooth pavement (the condition where you are least likely to get into an accident). Inclement weather changes a lot of performance variables, and it depends very much on the tires installed.
It should be noted that early Model 3 owners manuals recommended 45PSI, and that's how they were inflated from the factory. I don't think it'd cause any real uneven tire wear, but the current 42PSI recommendation certainly softens the ride a bit.
Your message is spot on all the way around! As you said - speed is the #1 factor in efficiency... tied closely to weather & wind conditions. Pushing yourself at 80mph against headwind is pretty murderous on efficiency.
Recommended tire pressure on the placard is just that and it is for cold inflation.
As you drive tires warm up and pressure increases but that does not affect the cold inflation pressure and tires should not be adjusted when not cold. I routinely run 46 psi cold which is under the max sidewall marked pressure. Helps range a little and does decrease traction because of the reduced tire contact patch size.
As you drive tires warm up and pressure increases but that does not affect the cold inflation pressure and tires should not be adjusted when not cold. I routinely run 46 psi cold which is under the max sidewall marked pressure. Helps range a little and does decrease traction because of the reduced tire contact patch size.
Yup they definitely used to recommend 45 PSI, but go check out some of the Tesla groups on FB (or even here sometimes) and you will see plenty of people posting tire wear photos saying "why are my tires wearing out" and they are clearly overinflated.
Tesla has motivation to recommend a high pressure because a) they don't really care about our tire wear and more importantly b) it will help efficiency to some extent, but it's a question of preference and diminishing returns IMO. I'd rather have a slightly softer ride with slightly worse efficiency and more even tire wear in the long run.
It used to be 45, but is now actually 42 PSI from the factory.
Msjulie
Active Member
Just a note that I keep my 3's tires to a cold 45psi and have pretty much since new and there is no uneven wear on the tires. FWIW both my tire gauge and the car agree the car is at cold 45 but of course, there is a +/- 1lb assumed error at minimum. I have made sure my alignment is spot on and rotate the tires about 6-7k miles so perhaps that helps. I prefer this setting as I can honestly feel the change in the ride and prefer a firmer ride and potentially higher efficiency.
We don’t put enough miles on our 3P- to judge.
I keep our S 100D tires at 48 psi. The sidewall COLD pressure limit is 50 psi. The tires end up around 53 psi at cruise. Even if one started out at lower pressure.
That suggests 53 psi is equilibrium for our S, cruise speed and climate. You can reach equilibrium either by:
Old-timer’s quick tire pressure check - put the back of your hand on each tire’s sidewall at the first stop. If one tire is noticeably warmer than the others, it has low pressure.
FWIW, I keep our 3’s tires at 46-48 psi. It’s my wife’s, her first car was a Fiat 124 Sport Coupe. Dual-cam, high-revving, well-balanced great-handling vehicle. She enjoys the 3’s improved road feel and responsive handling at the higher pressure range. Yes, treadwear is even on that car, too.
I keep our S 100D tires at 48 psi. The sidewall COLD pressure limit is 50 psi. The tires end up around 53 psi at cruise. Even if one started out at lower pressure.
That suggests 53 psi is equilibrium for our S, cruise speed and climate. You can reach equilibrium either by:
- Starting at relatively high pressure, relying on heat from moderate sidewall flex to close the gap. This is energy-efficient and kinder to the tires.
- Starting at lower pressure, relying on higher degree of sidewall flex to close the larger gap. This requires more energy and demands more of the sidewalls
- Limit case is tire pressure well below manufacturer recommendation. This flexes the sidewalls so vigorously, and heats them so much that a blow-out ensues.
Old-timer’s quick tire pressure check - put the back of your hand on each tire’s sidewall at the first stop. If one tire is noticeably warmer than the others, it has low pressure.
FWIW, I keep our 3’s tires at 46-48 psi. It’s my wife’s, her first car was a Fiat 124 Sport Coupe. Dual-cam, high-revving, well-balanced great-handling vehicle. She enjoys the 3’s improved road feel and responsive handling at the higher pressure range. Yes, treadwear is even on that car, too.
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