FUZION ZRi tires,,great alternative for F-Body

[TimeLord]

have been testing them since Thursday,here is my appreciation of them !!!

DRY = The sidewall is a softer than the SZ50 so it flexes more in very spirited driving at 32PSI,I tried them at 40PSI and the are pretty near what the SZ50 was. I will try various other inflations over the next week and keep you posted. I figure it will end up like 35-37 PSI range. Did 150 miles this morning on the way to the track at 40 and it was a little too firm for my taste,on the way back tried 40 front/32 rear it was better but not ideal.

WET= Forget the SZ50,these things are superior in every way,traction from a dead stop,from a roll,cornering,lane change,standing water,slalom on wet even.These things are FANTASTIC.

Drag racing= I am geared 4.11 so anything i tried[rpm] ended up in smoke or wheel hop[30lbs],maybe someone with saner[3.42/3.23]gearing can test them and report.

Treadwear= I cannot believe these things will last as long as the SZ50 or the SZ50EP,they are WAY too sticky in my opinion,unless they came out with a newer compound.

These things are GREAT,and if you figure in the price they are INCREDIBLE!!!!!!!!!!

[95z28]

Couldnt have posted this at a better time ... because i am lookin to get new ones and i was rather upset the sz50 doesnt exist any more.

[wolfdogs]

remember.....with tires.. cheap .....meand simply that. cheap.

there is a sacrafice somewhere...whether it be tread compound for wear......or overall construction quality.

you test is not valid for comparison purposes. if you inflate to 40 psi..you are NOT "where the sz50 ep" is.... you cant be.. because you have reduced the size of the contact patch now, which means less grip on corners.

the "stiffer sidewalls" are the stabilizer for the belt package/crown edge support...... thats what keeps the contact patch stable on hard cornering....... flimsy sidewalls at correct inflation pressure and size for the vehicle they are on mean just that... flimsy.

the only valid tire test is to virtualy eliminate all variables. you cant play with inflation pressures and get valid results for comparison.

just my 2 centavos...........

[TimeLord]

That is why I said right off the bat that the sidewalls were softer on this tire than on the SZ.

The psi is me trying to find a comfortable and safe compromise with these tires.

They are designed for the TUNER crowd that run HUGE rims and no sidewalls withn 35-40 aspects.

Bridgestone/Firestone supplied these to me to see how they fare on a big heavy car with bigger sidewalls,all in all I was very surprised by the performance of these tires.

I figured that for the $$ they must be very plain if not downright horrible.

In the wet these blow the SZ away in every way.

On dry they are softer[as stated in opening post]and flex more in hard cornering than the SZ did,but they still stick like crazy in 95% of conditions that I will encounter.

Are they better than the KWD or GS-D3,of course not at extreme limit,I never said they were,I stated that they were a viable option for someone whose SZ's are used up.

I have them at 35lbs and they feel pretty comfortable,not as killer as the SZ at extreme dry limits,but much better at EXTREME limits wet[INCREDIBLE] !!!




P.S.// I know how to do valid comparitive testing,,,,

[Joe 1320]

I know what you are trying to communicate but in all fairness, there should be an identical set of same sized wheels and tires from the two manufacturers. It is nearly impossible to compare them any other way.

As an example, I had a set of "cheap" Pep Boys ultra Zs. They were made by cooper and with full tread, had way better grip than my 50% worn SZ50s. I was pretty darned impressed until the coopers got down to the same tread as the SZ50s. By then the grip had gone away and the SZ50 was better. Then, as the SZ50 wore down, their grip went even farther away, leaving the Coopers with better traction.

Each tire is made to perform within a certain "window" for ratings. One tire may have a hard outer surface for initial treadwear rating test, then as it wears, the compound is softer. Some tire are the opposite. They get harder as the tread wears. That was the whole deal with the SZ50EP. A different compound that kept the tread softer for better grip as the tread wears. The old SZ50 was great until it wore down, then the grip went away.

I would be most interested in a side by side comparison of the two tires, side by side with identical testing proceedures. No doubt this tire may be a value to some, but hard evidence would be needed for me before I could draw my own conclusions. I would imagine eventually there will be this kind of test.

[Fastbird93]

So the SZ50 isn't available anymore, even as the EP or whatever it is???

[TimeLord]

Not unless you want run flats[EMT].

[TimeLord]

Joe!!!!

These are the same size tire and the same rims,I have been running SZ50 since 99 and am probably one that knows these tires the best.

As for wear I am supplied with new tires every year,the SZ I just replaced were worn to 8/32nd and 7/32nds,I would love to do a side by side test of the two.I have however been invited by B/F to a comparison day VS. the Pilot Sport,that should be interesting.

I am anxious for the TIRE RACK or a magazine to do a comparo,I feel that my evaluation will not be far off.

Like the Camaro winning the Bang for the Buck comparo in 94,it was outclassed by the RX-7 TT but once $$ was factored in the Z28 won,this is what I am trying to say about the tire.

How it will wear,I don't know but I told the rep that the treadwear rating was too high,no way these will last like the SZ's,which is perfect in my book.

[Joe 1320]

Are you comparing the SZ50 or the SZ50EP? The EP is a far better tire than the regular SZ50...........The old SZ50 (I've had 3 sets of those since 97) were a fairly decent tire, but don't have the grip of the EPs. The other thing is consistancy. The old SZ50 to me was a little inconsistant. The whole thing is likely a moot point as if the tire has gone away, then a comparison doesn't really matter.

I still would like to see a comparison of the same tread depth, same wheel, same day, same temps, same car, same driver, same exact circumstances yet done back to back. To me, that is a far more accurate way to do a fair comparison.

[wolfdogs]

P.S.// I know how to do valid comparitive testing,,,,

_________________________________________

and so do I, having spent 14 years heading up the Govt. Qualified Prouct List Testing program for Tires, that included passenger car, light truck, truck bus, earthmover, and industrial tires.

All the testing parameters and procedures were under constant watch from tire engineers from all the major manufactures......as was the actual testing being done. I wrote those test parameters and the forumals for data extrapolation. i also served on NHTSA comittee's for tire failure anaylisis, and the Society of Autmotive Engineers comittee for the development of SAE J1561 which defines the parameters for the testing of speed rated tires...
"so...whats your point, wolfman"?......

the point im trying to make is....having given my background, trust me when i say: tires are a much more complex unit than most people realize. there are so many varables that affect the performance of the tire's treadwear, foot print stabilization, heat dispersion, rolling resistance, bead seating, wet traction, dry traction, tread squirm, block shaving....you name it). changes in ambient temperatures affect it, road surface affects it (not only for treadwear, but heat and handling), inflation pressures, rim size, both the diameter of the tire/rim width and actual width of the rim the tire is placed on, the drivers input, what vehicle its mounted on, even the torque of the engine operating that vehicle..........

varables abound.........

Ken Ball, a long time friend of mine, was one of the chief engineers from Bridgestone/Firestone that had a hand in designing the Firestone Firehawk SV50. (some of you canadians may know the Ball family..they were heavy into racing in canada a while back and since have retired from it). The orginal SZ50 was designed for racing in the rain at Indy....thats where the tread pattern came from..and most of the structual design........ thats one heck of tire they came up with...both for Indy and commercial sales.

a typical treadwear/carcass durability/performance handling test runs upwards of $22,000 for a single sameple (two tires).... its a very complex issue involving a very complex animal


ride on..............keep the shiny side up and the dirty side down..........

[TimeLord]

I have used the EP the last few years since the non EP wasn't available for the last couple of years.

I actualy preferred the NON EP for drag racing!!

We don't live in a perfect world,I am doing my best with what I have,same car,same tire size,same condition[dry],same temp,same driver,same road,same driving style,one hour difference between runs,only variable was the 2-3/10ths wear.

This is the closest I can come to IDEAL test criteria !!!!!

On dry the softer sidewall was a letdown because it took a while to get used to the compliance of the tire as compared to the EP.

In the wet this tire feels WAY more stable and less apt to hydroplane than the EP when brand new,even in curves with standing water.I do about 2k worth of WET driving a year on the highway,I know how they react!!!

[TimeLord]

KenC !!!!

I never put your competance in question,I know you are the go to guy for tires,or wolfdogs .

I know TESTING is very intensive,time consuming and expensive.

I was giving my impressions of the tire and to the best of my ability trying to let people know the good and bad of the it.

SOTP is all I have,but it is a pretty experienced S that is giving it's opinion!!!!!

[wolfdogs]

Originally posted by TimeLord
KenC !!!!

I never put your competance in question,I know you are the go to guy for tires,or wolfdogs .

I know TESTING is very intensive,time consuming and expensive.

I was giving my impressions of the tire and to the best of my ability trying to let people know the good and bad of the it.

SOTP is all I have,but it is a pretty experienced S that is giving it's opinion!!!!!

that post was ment to set the stage for future thoughts on tire evaluations.........thats all.

[TimeLord]

Kool !!!!!!

[Joe 1320]

I can see where you are coming from. I have put probably 50K miles in the rain just on this car........ That's what it does here in Florida during the summer, torrential downpours that occur every afternoon from between 1 and 6 pm. That was why the Firehawks were my choice. If there is something better in the rain, I'll be all for it. I actually have several sets of Wheels and tires that I swap around, depending on conditions. In reality, the Firehawks were much better than the original GSCs, but there are still grippier tires out there for the dry. The SZ50 was a great compromise.