I purchased my MCS this summer, and noticed over the last couple of months that my gas mileage has been declining - harder to reach those high numbers on my on-board computer. It finally occurred to me to check my tire pressure, but I've been putting it off a little because the hassle of doing this at a filling station. So this morning I went out to my driveway, pressure checker and bike pump in hand, and lo and behold - I was running around 26 lbs all around !

So, a couple of tips to everyone:

1. Check your pressure - it's probably down.
2. It's easy to fill at home with a simple bike pump - 15-20 compressions and done.

Happy motoring !

 

The point here is not to wait until the tire pressure sensor alarm goes off, because if you're losing air in all your tires at the same rate, the system will never think that one is 'flat' or low on air!!

 

I never thought of pumping it with a bike pump!!! I have a compressor btw.

 

If you have the sport package, you have the 17" tires, right? The pressure is pretty high--38, I think. I've got the 16's (dealer swap out), for it's 33 for mine, although I usually run a little higher. At any rate, check the ower's manual. They've got a nifty 2 page chart.

I've got one of those little compressors, too, and it's a good way to check out operation, before you find yourself stranded on the side of the road because of a missing part or something.

 

I was wondering why I was only getting 17MPG, I checked my tires this morning, I was running 26 pounds all around!

 

Very true...thank you for the reminder!

 

Was I the only one checking every week?

 

Inside my door it reads 38 PSI the tire reads max 51 PSI ,I'm splitting the difference .38 feels to low 51 feels like there gonna blow .So which one is correct ?

 

I check air pressure every month for sure. I run 36lbs. When I took delivery the pressure was different in every tire. No 2 alike. Also, remember that as cold weather approaches, air pressure goes down. I checked and was down from 36 to 31 in all 4 tires. As someone else posted, when all 4 drop, there is no warning of low air pressure. Tire gauges are still a good item to have and use.

 

I have one tire that has a really slow leak so I have to check them all the time.

One of the best ways America can increase their gas mileage, proper tire pressure, not to mention the other benefits...proper traction, tire wear....

My high pressure road bicyle tires (125psi) loose about 1psi a day so I must pump them up every ride.

 

The max PSI on the tire is what the tire is rated at for it's maximum payload. In other words if you have the maximum indicated weight on the tire, you need to run max PSI.

Since the tire fits many vehicles, with different weights and weight distribution, it's best to stick with what the manufacture recommends, or the door sticker. Mini knows the weight of the car and took that into consideration when recommending tire pressures for standard size tires (that's why the door sticker also gives tire size info).

My other non-MINI car is also front wheel drive and it's sticker recommends 2 more psi in the front tires. It's very light in the back and not following that makes the rear tires wear out down the centers.

The sticker's recommendation is for COLD readings. Manufactures take into account the increase in pressure as the tire warms up. The sticker number is adjusted for not only the cars weight/weight distribution, but also the increase in pressure once the tire warms up. Which leads to another discussion when getting tires at places like Costco who fill from Nitrogen tanks, keeping the pressure increase due to temp at a minimum. Altitude changes also affect tire pressure. When I set my track bike up at my house, if the track I'm going to is at a different elevation, the pressure will be a couple PSI difference.

 

Both nitrogen and "regular air" (which is almost 80% nitrogen anyway) follow the ideal gas curve for temperature versus pressure almost perfectly, so the amount of pressure you gain/lose because of temperature isn't going to depend on what gas your tires are filled with.

As for differences due to altitude, they're minor. Atmospheric pressure only varies by 1 psi for every 2,000 feet in altitude change. To use an extreme example, if you fill up your tires in Miami, and then take them to Denver, you'll find that they'll read about 2.5 psi higher in Denver.

Note that this does *not* mean that you should let air out of the tires once you get to Denver. The higher reading is *only* because of the lower atmospheric pressure, not because you've gained pressure inside the tire. If 38 psi is the "right" pressure when you're in Miami, and the same tires read 40.5 psi in Denver, then 40.5 psi is the "right" pressure for Denver.

 

Yes, I have the sport pkg with the larger rims, with all weather tires. These smaller tires will have less air than the standard tires, so a small air loss should make a bigger difference than with standard size tires. I fill to 36 lbs, which is the normal pressure. I last checked maybe 4 months ago, which I'd expect to to be a fairly insignificant time.

I have a compressor too, but it's more of a hassle for me to use than simply grabbing the bike pump.

I didn't do much that I'd consider invitation to rapid tire pressure changes, but obviously I am going to keep an eye on this as getting better mpg, performance and tire life are all highly motivating.

 

Nice way to get some beneficial exercise, too...pumping those tires by hand and not using a compressor.

 

Thank you Bill Nye.

 

You need to work out more than once every six months to see any benefit.

Just sayin', is all.

 

Ewwwwwwwww....

 

Can someone please recommend a good compressor...maybe one I could also take to Auto-x?

Also, I no longer have stock run-flats...instead I have 215/45/17's.....what pressure do I go by?

 

With all the preoccupation about bonnet, boot, hood and wing nomenclature, shouldn't this discussion be about tyres?

 

I merged this thread with another with the same name and content here in MINI Talk to consolidate things. Just wanted to let everyone know. Thanks!

Mark

 

I have already edited my post accordingly.