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Location:
Brisbane
Registered:
July 2002
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Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 14:08
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Hey,
Ive been pondering the idea of how much wider I can go in tyre width on my current rims. The problem is that when choosing rims for my car theres basically nothing that caters to my cars offset etc etc. So what I ended up with was 17x7.5's.
Currently Ive got 234/45/r17's Dunlop FM901's on there and they handle well, feels like the sidewalls are a bit soft and it wobbles a tiny bit on them.
My problem is more straight line traction, i was looking at getting wider tyres to try and help that(at least a little).
So whats the widest tyre I can go thats legal, safe, wont affect handling on my current rim.
Thanks
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 15:25
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235's would be prettey wide even for a 7.5 " rim
I have 205's on my 7" wide rims and i dont think anything bigger than 215's would be practicle.
It may be that you are getting sidwall flex cause the wider rubber squirms on the rim (i could also be talking out of my ass)
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I Supported Toymods
Location:
Lwr Templestowe, Melbourne
Registered:
August 2004
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Re: Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 15:32
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| 4agte wrote on Wed, 15 June 2005 01:25 |
235's would be prettey wide even for a 7.5 " rim
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I got 235/60/14 on my 7" rims. As for it being legal/safe/balanced, I got no clue. Needed the size for traction and it doesn't look as if its totally bulging out from the rims...
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Location:
Toronto, Downtown
Registered:
September 2004
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Location:
Brisbane
Registered:
July 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 15:46
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the 235's on mine definately dont seem too big.. ill definately be trying to go 245 at least.. but i want to know if 255 would be oversized for the rim
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 21:50
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very interesting link says that 215/45 r15 would be ideal for my 15 X 7's
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I Supported Toymods
Location:
Sydney
Registered:
December 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Tue, 14 June 2005 23:08
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I've got 215/40's on my 17x7's and they are a perfect fit so 235's shouldn't be a problem for 7.5's
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Location:
Brisbane
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 01:11
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If you want greater straight line traction the first place I would be looking is to fix you massive negative rear camber...
/ \ is never going to get great straight line pickup, esp when the car is going to squat more under heavy acceleration...
Also there is a point of note here regarding tyre sizes, what you want is the greatest area and the greatest coefficient of friction between the tyre and the road....If you goto a much wider tyre you may get more surface area on the road, but the pressure per tyre area is now less (due to pressure = force/area; the force is the mass of the car times gravity, both of which don't change in this equation due to the fitting of wider tyres...so we can see the pressure is going to become less...).
How does this lower pressure between the wider tyres and the road change/effect the tyre/road coefficient of friction? I have no idea  But it's something to thing about...(I'll also make a note here about rally cars, they run on a very low grip surface but run quite/very thin tyres 185/195's on 15" rims....something tells me we can learn from this...)
Cheers
Wilbo
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 01:12
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A 255/40 tyre is not legal on a 7.5" rim.
It must be on a 9 or 9.5" as recommended, but is allowable on a 8.5 to 10" rim.
Even a 235/45 is recommened to be on a 8 or 8.5" rim, but is allowable on a 7.5 to 9" rim.
A lot of it has to do with the width AND aspect ratio of the tyre.
Try a different tyre rather than the actual size
Cheers
MB
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 03:56
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1) Your wheels are 17x7", not 7.5". Remember 
2) I'm with Wilbo, I'd say most of the traction issues you're having are through negative camber.
3) Most of the squirminess you're feeling is probably due to the car squatting even more and making said negative camber worse.
4) For such a light car, you'll probably find anything bigger than a 235 may make traction worse.
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Location:
Brisbane
Registered:
July 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 04:24
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shit, they are 7".. i dont even remember 'ey
might find some different, wider rims
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 04:47
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| Jag7799 wrote on Wed, 15 June 2005 13:54 |
shit, they are 7".. i dont even remember 'ey
might find some different, wider rims
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Wider rims will not help with the camber issue as raised by JCMF. It may not just bbe the tyre also, it may be the whole system is a bit worn. Have the bushes been changed ?
First step would be to innvest in some REALLY good tyres as a first point ...
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Location:
I wanna go Hawaiiiiii.......
Registered:
November 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 05:01
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Wider will notfix your problem, first make sure camber is correct under acceleration. And if tyre sizes are of concern you will get better traction with taller sidewalls than with wider tread pattern.
If straight line grip is the main aim try for some good quality sports tyres in 60 series, you will be very surprised.
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Location:
Brisbane
Registered:
July 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 05:20
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Everything in suspension system has been replaced
All bushes replaced with urethane stuff. Shocks, springs, even things as silly as rack ends etc.
Not after straight line traction as the be all and end all, main concern is how it handles.. but, in saying that would like a bit more traction
Dunlop Fm901's are some really really good treaded tyres, the next sort of option up would be road legal semi slicks
Camber is obviously an issue and has been raised and I will look into it
I think 45 is a tall enough sidewall
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 06:25
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| Jag7799 wrote on Wed, 15 June 2005 14:50 |
Dunlop Fm901's are some really really good treaded tyres, the next sort of option up would be road legal semi slicks
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I would disagree quite strongly on that point.
Eagle GSD3's, and plenty of other tyres would provide much more grip !!
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 06:28
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| bbaacchhyy wrote on Wed, 15 June 2005 14:25 |
| Jag7799 wrote on Wed, 15 June 2005 14:50 |
Dunlop Fm901's are some really really good treaded tyres, the next sort of option up would be road legal semi slicks
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I would disagree quite strongly on that point.
Eagle GSD3's, and plenty of other tyres would provide much more grip !!
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I dunno how you'd quantify it, but I'd be skeptical about that last statement. FM901's get kick ass marks in every tyre test I've read for their performance, but get butt-raped when it comes to longevity
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 06:43
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| justcallmefrank wrote on Wed, 15 June 2005 15:58 |
| bbaacchhyy wrote on Wed, 15 June 2005 14:25 |
| Jag7799 wrote on Wed, 15 June 2005 14:50 |
Dunlop Fm901's are some really really good treaded tyres, the next sort of option up would be road legal semi slicks
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I would disagree quite strongly on that point.
Eagle GSD3's, and plenty of other tyres would provide much more grip !!
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I dunno how you'd quantify it, but I'd be skeptical about that last statement. FM901's get kick ass marks in every tyre test I've read for their performance, but get butt-raped when it comes to longevity
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In Wheels May 2005 issue, they did a tyre test, and out of 500 points, the following 235/45x17 tyres scored the following results (RRP in brackets) ;
#1 - Goodyear Revspec RS-02 - 496.0 ($298ea)
#2 - Michelin Pilot Preceda - 494.7 ($290 ea)
#3 - Maxxis Victra MA-Z1 - 493.5 ($198)
#4 - Bridgestone Potenza S-03 - 492.8 ($355)
#5 - Toyo Proxes T1R - 487.8 ($312)
#6 - Yoko AVS Sport V-102A - 484.4 ($359)
#7 - BFG G-Force Sport - 479.5 ($201)
#8 - Dunlop Direzza DZ 101 - 474.3 ($288)
#9 - Kuhmo Ecsta KU19 - 471.5 ($235)
Since the FM901 is replaced by the Direzza and that the FM901 is an old design, I would say that it gets its ass kicked !!!
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Location:
sunny coast, qld
Registered:
October 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 06:58
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Get some Simex 225/60-15's 
Make some positive camber on the rear so when it squats you get maximum contact patch and you are ready to race
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 07:32
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+ve camber sucks unlkess it's a pure drag car. some slight -ve camber is ideal for overall use (as long as you dont mind losing a few months off the life of your tyres)
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 09:38
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| draven wrote on Wed, 15 June 2005 17:32 |
+ve camber sucks unlkess it's a pure drag car. some slight -ve camber is ideal for overall use (as long as you dont mind losing a few months off the life of your tyres)
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it depends how fast you like to go arround corners having more -tive camber can give even wear across the tyre giving better tyre life
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 09:56
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| bbaacchhyy wrote on Wed, 15 June 2005 14:43 |
Since the FM901 is replaced by the Direzza and that the FM901 is an old design, I would say that it gets its ass kicked !!!
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Are the Direzza a direct replacement for the FM901 though, or just the one that filled the gap in the Dunlop range? The FM901 were great, but they were pretty f'ing soft
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Location:
Sydney
Registered:
September 2004
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 09:56
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| bbaacchhyy wrote on Wed, 15 June 2005 16:43 |
| justcallmefrank wrote on Wed, 15 June 2005 15:58 |
| bbaacchhyy wrote on Wed, 15 June 2005 14:25 |
| Jag7799 wrote on Wed, 15 June 2005 14:50 |
Dunlop Fm901's are some really really good treaded tyres, the next sort of option up would be road legal semi slicks
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I would disagree quite strongly on that point.
Eagle GSD3's, and plenty of other tyres would provide much more grip !!
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I dunno how you'd quantify it, but I'd be skeptical about that last statement. FM901's get kick ass marks in every tyre test I've read for their performance, but get butt-raped when it comes to longevity
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In Wheels May 2005 issue, they did a tyre test, and out of 500 points, the following 235/45x17 tyres scored the following results (RRP in brackets) ;
#1 - Goodyear Revspec RS-02 - 496.0 ($298ea)
#2 - Michelin Pilot Preceda - 494.7 ($290 ea)
#3 - Maxxis Victra MA-Z1 - 493.5 ($198)
#4 - Bridgestone Potenza S-03 - 492.8 ($355)
#5 - Toyo Proxes T1R - 487.8 ($312)
#6 - Yoko AVS Sport V-102A - 484.4 ($359)
#7 - BFG G-Force Sport - 479.5 ($201)
#8 - Dunlop Direzza DZ 101 - 474.3 ($288)
#9 - Kuhmo Ecsta KU19 - 471.5 ($235)
Since the FM901 is replaced by the Direzza and that the FM901 is an old design, I would say that it gets its ass kicked !!!
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I agree that the FM901's suck ass. I've got them on my sprinter and they just DO NOT GRIP... especially the fronts. Far too much sidewall flex as well. The only other tyres i've given a really hard thrashing are michelin preceda, faulken st-115 and goodyear dsg2's. All 3 of these smash the dunlops.
Eddie.
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 21:19
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| justcallmefrank wrote on Wed, 15 June 2005 19:26 |
| bbaacchhyy wrote on Wed, 15 June 2005 14:43 |
Since the FM901 is replaced by the Direzza and that the FM901 is an old design, I would say that it gets its ass kicked !!!
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Are the Direzza a direct replacement for the FM901 though, or just the one that filled the gap in the Dunlop range? The FM901 were great, but they were pretty f'ing soft
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Quote from the article ;
"The nine tyres selected came from the premuim brands that make up 70% of the Aussie market. The umpteen brands compriising the other 30% are largely irrelevant to the discerning buyer"
Whether it is a direct replacement or not, I guess it is their premuim one.
If you look at BFYB, the Maxxis does sensationaly well, and actually was the best in the wet braking (best by 0.32 of a metre) and the noise tests (quieter by 1dB), only 0.6% worse in the dry braking, thrird in the wet cornering test by 0.2 of a sec, 4th in the dry cornering by 0.8 of a sec, 6th in the Slalom by 0.39 of a sec. All for $200 a corner ....
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 22:02
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so which one came out top for dry cornering/braking?
and was pirelli in the list?
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Location:
Adelaide
Registered:
September 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Wed, 15 June 2005 22:26
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| draven wrote on Thu, 16 June 2005 07:32 |
so which one came out top for dry cornering/braking?
and was pirelli in the list?
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Dry Cornering - Potenza S-03
Dry Braking - Goodyear Revspec
No Pirelli.
The interesting thing when you read the full article on how they did the tests, is how close some of the tyres were.
I was impressed by the Maxxis performance for the price.
The way the points worked out was that the winner got 100 points, and whatever % the other tyres were behind is what score they got. e.g. if the second tyre was 0.8% worse, it then got 99.2 points for the test, if it was 3% worse, it got 97.0
So the Maxxis out of all of the tests was only a combined total of 0.5% worse than the winners cumulative score !!!
No, I am not a Maxxis dealer !!!
The tyre I was going to go for was the Goodyear GSD3. Not any more...
More on the BFYB version (sorry about the formatting), but if you concentrate you can work it out ....
Rank Tyre Wet Stopping Dry Stopping Wet Cornering Dry Cornering Slalom Cost per Tyre $/Point Points/$
1 Maxxis Victra MA-Z1 100.0 99.4 99.7 98.6 95.8 493.5 $198 $0.40 2.49
2 BFG G-Force Sport 93.0 98.4 95.3 96.7 96.1 479.5 $201 $0.42 2.39
3 Kuhmo Ecsta KU19 95.6 91.1 98.6 92.5 93.7 471.5 $235 $0.50 2.01
4 Michelin Pilot Preceda 98.8 99.7 97.9 99.1 99.2 494.7 $290 $0.59 1.71
5 Goodyear Revspec RS-02 98.5 100.0 100.0 99.3 98.2 496.0 $298 $0.60 1.66
6 Dunlop Direzza DZ 101 94.4 90.5 96.7 97.0 95.7 474.3 $288 $0.61 1.65
7 Toyo Proxes T1R 98.3 99.6 99.8 95.7 94.4 487.8 $312 $0.64 1.56
8 Bridgestone Potenza S-03 95.0 98.7 99.1 100.0 100.0 492.8 $355 $0.72 1.39
9 Yoko AVS Sport V-102A 93.8 96.3 97.6 97.9 98.8 484.4 $359 $0.74 1.35
The results are very different .....
[Updated on: Wed, 15 June 2005 23:03]
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Location:
Newcastle, Australia
Registered:
March 2005
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Re: Widest Legal/Safe/balanced tyre.....
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Thu, 16 June 2005 00:09
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AFAIK Pirelli didn't provide any tyres for the tests. So no idea where they would slot into the rankings. I'll have to check my copy of the magazine when I get home if anyone wants confirmation.
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Location:
Brisbane
Registered:
July 2002
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Re: Widest Legal/Safe/balanced tyre.....
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Thu, 16 June 2005 02:49
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When i bought the FM901's i read all the reviews of the time and they were up the top of the lists. They were also ranked up top in dry cornering etc but not so awesome in the wet(which i dont really care about)
this was a year and a half ago when i got them, so you need to be a little lenient
Ive done around 10 000k's(maybe) so i doubt ill get more than 20 000 out of them total but they have done me well
And unless you compare the direzza and fm901 side by side you cant really say that its instantly better(even though it should be)
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Location:
Sydney NSW
Registered:
July 2004
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Location:
Osama's hideout
Registered:
February 2003
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Re: Widest Legal/Safe/balanced tyre.....
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Thu, 16 June 2005 04:41
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iam running 265/35/18 on my 18x8 inch simmons, they hook up great and if i want them to spin, i just short shift on gear changes and it will leave two very black 265 foot prints for as long as i like,
on the drag strip i run 255/50/16 on a 16x7, they are baggy on that size rim but thats what i wanted.
hope this helps,
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