Best tire pressure for the Prius C?

What size are the factory tyres?

I am running 48f 46r in my 195/65/15 winter tyres currently. Hard, but improved mpgs

 

Best for what? MPG, comfort, tread life? I run the sidewall max (51PSI for my tires) for MPG's, ride quality is good enough for me. I would go to at least 40PSI as a good compromise.

 

Most people who run high pressures report great tread life, so pretty much as high as you can stand ride-wise is what you should use. As long as the cold pressure is not higher than the sidewall max, you shouldn't have any problems. Some people go even higher, but that's at your own risk.

 

It's written on the side of the tyre!

 

I ride the stock Turanza at 36/34 and still manage 60 mpg on my daily 40 mile commute. Tried higher pressures when I first got the car, but decided to go for ride quality.

 

Not only will the ride quality suffer, so will the longevity of the suspension parts.

With the tires over-inflated, the shocks/struts and other suspension parts take more of a beating.
If you plan to keep your car a LONG time, the trade-off might not be worth it.

 

As rjdriver & Easy Rider say - it's a trade off.

I found that my MPG does not increase much - if at all - beyond about 38 PSI so I keep it at that pressure.

Even at 36 PSI the MPG is good. Here is Hawaii there's not much chance to drive 70 mph for long stretches. Although if I'm not paying attention and the traffic is not too bad - it's real easy to end up going that fast without realizing it.

That said - my MPGs stayed the same or went up slightly when I had a flat and I was running the compact spare - go figure.

 

I have a new C4 and from the dealership the tires were at 32 psi. My commute mileage was 51 mpg at the first fill up. I increased the tire pressure to 40 psi and my mileage now is 56 and no difference in the ride.

 

No difference that you notice, that is.
An increase of 8 lbs would certainly put some additional stress on the suspension.

Also, the engine efficiency tends to improve a tiny bit as it gets broken in good.

To prove your point, you would need to put them back where you found them and see what happens.....or back to the cold recommendation, that is.

Which pressure is "right" depends on what size tires you have. I was surprised that the pressure recommendation is so much different for the two standard tire sizes.

 

Given that the max tire pressure is 51 I hardly think 40 is going to stress the suspension.

Nexus 7 ?

 

I'm only using 240F and 230R which is about 35/33psi

I find that a good compromise on ride and handling.

 

You can think whatever you want but the suspension is a total package and it was designed for the
tire sidewalls to take up part of the travel, mostly some of the constant tiny movements due to pavement irregularities. Running a couple of pounds over the recommendation shouldn't cause any real difference but +8 pounds might be a different story.

The max. safe pressure stamped on the sidewalls has nothing to do with it.
Granted it might be a small gamble but it IS a real concern.

 

I think that part of it is where the cars operates mainly, i.e. in cities where the roads arent great or on a perfectly smooth motorway. If the latter, there will not be much of an issue with regard to running high pressures.

I do alot of city driving and the roads in Dublin here are not great to say the least. I am going top reduce the tyre pressure gradually over the next week or so. I am not happy with the ride quality since increasing to 46+ psi. I'll take the hit on mpg for more comfort and less hardship on the car

 

Ah Ireland. Beautiful country.

And I know that many of the roads in Europe are better than in the US but.......
NO motorway is "perfectly smooth".

If you don't believe that, inspect a few on your hands and knees.........OK, well probably not possible; just have a good close look from the shoulder.

Running pressures as high as you stated in a tire that is not intended for heavy loads is hard
on the tire too.

 

In fairness, some of our new motorways are very very smooth and if I was only driving them I would be ok with the high pressures. I've worked on the building of motorways here and have looked at them closely. They seem to differ based on location, who is paying for it and also the contractor doing te Tarmac/asphalt.

We have very few roads left here that are concrete, most have been replaced.

 

So now you have me worried so I aired down to 34/32.