At diameter of 24.6" for 185/80x13 tires they appear to be greatly oversize, costing acceleration, mpg and probably rubbing issues.
Sure they aren't 185/70x13's? 23.2" would probably work OK in rear over drums but 13" wheels look a 'trifle crowded' on the calipers in front.

And if your CRX is old as mine those snow tires might be a 'trifle' old as well and not very suited to snow duty.

 

Not you too…I had a better opinion of you mahout.

Get a GPS in your car. Set your front tire pressure to 20-psi. Zero out your odometer and your GPS. Go 100 miles and jot down the difference between what the GPS shows and the odometer. Now put 40-psi in your front tires. Do the same driving test. I’ll bet you will see 4% difference.

 

You didn't change tire structure; you only changed tire pressure (by a whopping amount) on the same tire structure.
Now do it again with truck tires and see what you get.
The listed revs per mile is for the nominal tire pressure for that tire. When you increase tire pressure the shape of the tire is changed within the structural linitations. And revs per mile as well.
Tires with heavier sidewalls, when subjected to differing tire pressures, change the shape less at air pressure changes so revs/mile don't change as muchas for passenger car tires.
And note there are differences in tire structures between manufacturers and tire lines.Weight is often a giveaway. Compare Hoosiers with Dunlops for example..

 

We’re not talking about trucks! We are discussing snow tires for a Honda Fit. OEM tires are radials and the snow tires are radials. No change in basic construction. I’m NOT sure of this, but I think that the suppleness of the rubber has a much bigger effect on the amount of sidewall collapse under loading. And the technology of the rubber formula in the last decade is what allowed the astronomical aspect rations of 35%, 40% and 45% of the tires. For these same reasons, I think (I don’t know, but I bill be testing my theory out next season) is the formula of the rubber that no longer requires snow tires to be tall and skinny. I will be using up my 195/55R15 snow tires in the next season or two and then I will be replacing them with 205/50R16 snow tires of the same brand and type. And because of the advances in technology, my theory is that I will get better performance on the ice and snow with the larger tires.

 

I'm thinking of getting snow tires and a new set of wheels, and my main question is whether to spend the extra money (nearly $300) to have the wheels outfitted with TPMS sensors and get the necessary TPMS programming tool.

(Doh, seems like Tirerack ran out of the TPMS sensors already, so now my choices are wheels + tires from Tirerack or get them locally with sensors for probably 2x as much :-/).

I have a 2009 AT Sport with Navi, which means I have VSA. According to the manual, if there's no TPMS sensors, I won't be able to disable VSA.

This is the first car I've had with stability/traction control so how big a deal is it if I can't disable the VSA? People say being able to spin your wheels might help getting out if you're stuck.

Any idea how this affects insurance coverage? Anybody heard of claims being denied because of nonoperational TPMS?

As an aside, I was probably going to get the Continental ExtremeWinterContact (195/60R15) with the Sport Edition D4 wheels (Sport Edition D4 Silver Painted)... any thoughts?

While I'm asking questions, anybody want to hazard a guess as to how the Fit with the stock Dunlops would compare to my previous car, a 97 Honda Odyssey with BF Goodrich Traction T/As (until they wore out after 20k) and Michelin HydroEdge tires in the winter?

 

I used truck tires vs passenger titres for iluusrtration of structure affects on performance.
There are significant differences in the structure of tires not only between manufacturers but between components of tires from the different levels by manufacturers depending on the performce criteria. . Rayon, nylon, steel, binders, and rubber formulations vary considerably as well as how they are 'assembled'. Truck tires too are radials and are much stiffer but there are the same differences between all levels of tires from the same manufacturer. Try flexing a high performance tire tread compared to a cheap tire. I used truck tires as a really good example of how structure changes tire performance.
It is the structure of the tire that determines just how it will deform with changes in pressure. Its a guessing game every race team has to deal with in determining the best pressure on which to race - or qualify. Depending on the tread compound its softness can vary from one tire to the next. Softer compounds are needed to impregnate (but not too much) the road surface but the construction of the carcass itself determines just how the tire shape will change with pressure changes.
In many cases changing tire pressures merely change the spring constant for the suspension and have literally no effect on the contact surface area. But that change can increase traction a great deal, of take it away.

Lower tire profiles came about because of radial construction allowed tlower profiles. Bias tires just couldn't flex enough not because of rubber formulations but because the cords simply couldn' handle the flex without breaking. Fifty years ago tire manufacturers knew they would have to make radials in order to improve the directness of steering inputs to tire response; bias could not do it well enough. They were well aware of Michelin tires then even..

And when you get around to testing don't surprised when you find narrower tires with good tread penetration (compound and design) into the snow or ice are better. or that slightly larger diameter tires increase ability to plunge ihru snow because the approach angle is less making the step easier into oncoming snow. Doesn't matter on ice; in fact may be worse as the tire then tends to 'ski' easier. On ice the difference is immaterial.
You may want to read a few SAE papers in preparation.

Good luck.

 

Since you are on this blog, I’d say it’s a very good guess that you are a car guy. I’ll also hazard to guess that you check your tire pressures regularly. If you do, TPMS is not for you. It was designed for the people that don’t know what a tire pressure gauge is. That is why they put an idiot light on the dash for them. Its extra weight and every time you change your wheels out, you have to get the computer re-programmed to recognize the “new” TPMS. Not for me…

My Fit’s an ’07…I could not answer your concerns about VSA. I don’t have it…if your VSA depends on TPMS, then that changes the ball game completely and my previous statement does not apply…you’re stuck with TPMS.

For the most part, wheels are a thing of personal taste…unless you are going for absolutely the lightest wheels you can find (which you should). If you don’t get the lightest wheels, then it’s all bling…

Like I’ve said earlier, I’ve got Nokian Hakkapeliitta RSi tires. They come directly from Finland. They are great. The Finns know a thing or two about extreme weather driving…after all, they live within the arctic circle.

 

Read here.

I3-43.HTML

 

Just happened to be changing to wet weather (winter) tires so we had the opportunity to see if that were true.
Unmounted pressure 35.0 psi on Winterforces
mounted pressure: 35.4 psi ditto on a 3200 lb vehicle. fronts, rears only .3 psi increase.
And yes we do have a gage that accurately reads tenths of a psi.

If you change the volume the pressure too must change and in relation to the absolute tempertaure. You can't fool Mother Nature.
I think your concept assumes that the tire will expand in section to make up for the flattening at the bottom. For cheap tires thats probably true. I notice though that in the video there is a slight increase. watch the needle move to the right covering the upper hash mark and fall back to show a gap when weight is removed. Is that right? I'd like to see the weight applied longer, at least long enough to remove transition effects. In our case we added 800 to 600 lb and waited a minute or two to stabilize before taking the pressure.

 

Does anyone else see the irony in that statement!

 

I saw the needle move slightly too, but I believed it was due to the rocking forward or backward on the seat, changing the viewing angle between the needle and background of the gauge (I forget what that effect is called). If you watch, you will see the person sit and gauge does not move, then the person rocks back (possibly twisting )and the gauge appears to move. Maybe I can find a better example sometime. However, that is taken from the University of Maryland. So you will at least want to note the answer if you go to that Physics course.

I have read tire tech articles in the past and tire pressure not changing when a tire is loaded was referred to as a paradox because you think the volume of air in the tire is changing, but it is not.

It is interesting that you saw a pressure change. Are you sure the temperature did not change at all while installing? You would only need a change of 3-4 degrees for the pressure change you saw. Was your environment controlled enough?

 

Parallax...

 

I know that Tirerack is HQ'd in the midwest, but is also in Reno. They seem to like the idea of selling dedicated seasonal tires over all-seasons. It is more profitable and may work in the upper Midwest, but not the mountain far West.

We just had a snowstorm yesterday, yes in late May. I was in 80F conditions last week. A guy in a Civic with summer tires was unable to make it up my street, while another Civic on stock tires sailed right by.

I drove the 4x4 Tundra (with General Grabber AT2's from Tirerack) but many dont have the luxury of a dedicated Winter vehicle. Even an AWD Subie WRX is worthless here on Summer tires.

 

All car manufacturers like the idea of four winter tires. Even at 45 degrees on a dry day a summer tire looses 30 percent of the tires traction. Add a little snow and ice and it is even worse. With a tire like the Grabber and a 4WD and you would be fine. A rear wheel drive car even with all season tires is not something I would want to do in the winter. There are some places where winter tires are a must. You would just have to decide when to take them off. Keep a floor jack in the garage and change them as needed.
If I can help let me know.

 

What happens to a winter tire when the pavement surface is above 80F? Conventional wisdom would be to changeover Thanksgiving and April Fool's, but our seasons are way to variable for that. If I was caught off the mountain with summer tires yesterday and tried to get home, it would have been impossible, unless the summer tires were no wider than stock and I was carrying snow chains.

When I had a BMW e36 it could actually handle light snow with all-season P600's, but RWD pickups dont do well here, even with limited slip.

 

When you drive a winter tire hard in hot weather, the tread rubber will chunk up and disintegrate.

This happened to some of the winter tires that Car & Driver tested that way (on purpose) a few years ago. And I have had it happen to me...we ran our rally car on snows all season to help on unpaved stages, but one July rally had several paved high speed runs, and guess what happened?

Now if you drive sedately on WORN snow tires (eg, those that don't have enough tread depth to be useful in soft snow or mud), you can save money by running your snows that last 5000 miles during the summer. But you DO need to have good treaded snows for the winter...

 

Those are the xtremes for a winter tire. They are going to wear much faster in warm weather. They will chunk in aggressive cornering as well. Just don't push it in corners and a tire like the Dunlop Wintersport would be fine.

 

Access to my area is not by freeway, but extremely twisty two-lane roads, CA 330 and 18. Aggressive cornering is normal driving here. Traffic conditions do not allow you to slow down to a crawl if it is safe to do otherwise.

 

last year found some closeout deals for some winter tires, hopefully find some this year!

 

I have run worn snows during the summer on a leased van and we were turning it in. They were fine on the van.