Tire ratings
 

Hi everyone.

I need to buy some all season tires. I am not looking for anything special, just a all around tire. I was at my local farm and fleet, and they had the Mastercraft 205/55/R16 that I was interested in. Though, they told me that they would not install it on my vehicle because it is not the correct "rating" that our svx's require (z I believe). How important is this rating? I'm not going to be driving at 150mph or driving on a track. Thanks for any information ahead of time.

Slawek

The correct speed rating is...
 

mandatory. However, it doesn't have to be Z, but pretty close to that high. Correct speed rating makes our cars drive like a SVX should and the suspension system requires performance tires.. not related especially to your speed or track is also a stability thing

The minimum speed rating for the SVX is V, which is good to 240 KPH (or 140-ish MPH)

dont want to get off topic but.....
 

what does the tire pressure have to do with this? i know the plate on the door says like 28 and 30 or something, but my tires say 44 max so i keep mine at 40. why does the svx say such lower #'s than the tire? and what should be followed?

The maxamum tire presure...
 

rating for the tire is not necessarily related to the tire pressure you need to have for the front and rear of your tires.

Some of the people have tested the functioning of the car when driving under different conditions and maybe will give you some input.

Keith:)

higher tire pressure results in a stiffer ride and more work by the struts,swaybar, etc. the recommended tire pressure is for when the tire gets hot while driving it increases in pressure and still rides comfortably. now we get to the debate I however run 35/32 psi in my cooper xeon tires and dont notice any difference in ride / feel some will tell you differently run what you are supposed to some will run 40ish some not as high

max as in maximum pressure, as in if you put in 40psi cold you are prob at max when hot. Why are you running at 40 anyway?

i check my tires hot, after about a 10 mile highway drive and another 10 +or- drive going about 40. i keep them at/around 40 because im afraid of hitting a pothole and making the side wall bulge (which happened to the car before i bought it). also, since i was asking about pressure im admitting i dont know about it. as in, i dont know the pros and cons of running 40 or running something lower. i do know that a higher tire pressure supposedly gives you better mpg, and a lower one will give you a smoother ride. other than that i am clueless about the pressure. so if anyone wants to help me out and let me know the differences and what i should run id be greatful. thanks!

The stamp on a tire's sidewall is the maximum cold pressure rating.
A tire will last longer and be less prone to internal friction related overheating with more air pressure.
Overheating kills tires. Low pressure = more movement/flexing/stress on the belts as the tire runs through it's contact patch = more friction = heat.

to anwer the original question...205's are way too narrow. The svx runs on 225's.

Tires are one thing that you really shouldnt go cheap on...spend the extra money to get a nice full set of reputable tires

A couple points:

If your looking for a summer tire, then Eric is bang on, 205 is too narrow. The car feels sloppy and like it wants to wander around on tires that small. However, that's what I run in the winter (205/55/16 Blizzaks), because a narrow tire gets better grip in loose snow than a wide one that will compact or float on the snow.

As for pressure, all pressures are listed cold. Do NOT set your tires to 32-ish PSI after a 30 minute highway run on a sunny, hot day. When your tires cool they will be far below 32, and into dangerous territory. ALWAYS set your tire pressure cold.

Anything below 30 PSI in a heavyweight car (like ours) makes me squeemish. In my summers I run 40PSI front, 35 rear (my tires are good to 51 PSI). Exactly what pressure you want is a personal choice, but keep it below the max pressure listed on the sidewall. (normal sidewall pressures are 35, 44, 51, 65, and 80 PSI, with 65 and 80 only being in the heavy SUV/truck tires).

Now, to speed ratings:

The SVX specifies a minimum rating of V, or 240 KPH (~145 MPH). This is sort of a "soft" requirement. For example, my snow tires are Q rated, good to only 140 KPH (~85 MPH). If you opt for a lower rated (cheaper!) tire, just be aware that you have limits that the car can surpass. Don't exceed the speed rating, and be aware that the car will not have the handling it does with a Z-rated sticky performance tire.

My humble opinion here....

Following the recommended (plate on the car) pressure should be followed with any stock tire/wheel setup. This is not only for handling, but also for the same reason to have correct front/rear circumference for the transmission and differential.

Tire rating is relatively important, but what the tire sales guy told you is complete BS. For summer tires, I'd say a V rating or better would be adequate unless you're planning on spending extended time on a road course where you'll be exceeding 100 mph for over 20 minutes solid.

Lastly, for a performance car, Mastercraft tires are not the way to go. They're manufactured in a mediocre, Wal-Mart fashion. I just priced out tires for my car yesterday. For 225/50/16 Nitto tires I was looking at $65/tire. Reasonable price, good tire. Spend some time shopping around for tires and your efforts will be greatly rewarded.

This is a reply I recieved from svxcess
 

When I talked to Radial Tire about replacing my tires with either another set of Yoko AVS db's or the Continental Extreme Contacts. Paul, the owner, asked me how I managed to pick the worst two tires on the market for the SVX.

He said that he doesn't even carry the Extreme Contacts anymore because of all problems he has had with them. Most of his customers came back after a couple of days and had them removed.

As far as the Yoko's are concerned he said it was an OK tire when new, but got progressively noisier after 20,000 miles. He even said it sounded like you had a bad bearing with these tires during the last half of their life.

He is very familiar with the SVX and what most of their owners want in their tires and told me that the new TOYO PROXES 4 was the best tire for this car, hands down. It is an ultra- high performance, all season tire, which is very quiet and responsive.

Do not confuse this tire with the Toyo Proxes FZ-4, which is a completely different animal.

He has the Proxes4 tire on all three of his personal cars, something he has never done before. He was very impressed by the quality, handling and most important the ride comfort and noise level. (For the record, he has a BMW 850 coupe, a Lotus Espirit and A Cadillac CTS)

Here are a couple of links to more information. Radial Tire is a no-nonsense, high-performance tire shop with a stellar reputation and I trust Paul's advice completely.

http://www.1010tires.com/tire.asp?ti...model=Proxes+4

http://www.toyo.com/tires/tire_lines.../proxes_4.html


This is my second set of Proxes4 for me and I just put a second set on my son's 92 pearlie. We have gotten through the past 3-4 Maryland winters without any problems whatsoever.

A little less than $99.00/tire.

The same ratio can be maintained with higher pressure.

No doubt, but if you don't have tires with a sturdy contact surface or too stiff of sidewalls, then you're likely going to get excessive wear on the center of the tire over time. I've run factory recommended pressure on many tires with many cars and the only wear issues I've ever had have been from alignment.