Tyre sidewall stiffness. Do you notice/care about it?
Discussion
I had Uniroyal Rainsports on the front of my MR2 Turbo. I thought they were pretty damn good! But then, the majority of the weight in that car was sitting over the rear wheels, so the front tyres were pretty unstressed. They were excellent at cutting through standing water too, which could unsettle the car.
On the other hand, when I bought my MX5 it had Pirelli P6000's on it, designed for a much heavier car. Tough to heat up, extremely stiff and with no defomation at all, seemingly. It could be a slippery bugger in the wet.
On the other hand, when I bought my MX5 it had Pirelli P6000's on it, designed for a much heavier car. Tough to heat up, extremely stiff and with no defomation at all, seemingly. It could be a slippery bugger in the wet.
Not considering myself deserving of the 'driving god' badge, I'd have gone along with the 'load of cobblers' argument, that although ultimate grip may well be measurably different, and perhaps how it let go when you lost it, in a normal road car you'd not tell the difference.
However, apparently the Monaro is quite 'fussy' with tyres, and when I went from Michelin PSS on the rear to a pair of Avons, I sold them within a few hundred miles as it just felt dangerous.
Not in a wheelspin way, as that'd be fun, but in a 'change lanes and feel the rear of the car sway to follow appreciably after the front' in a horrible pendulum motion. I'd not noticed this for the first few fairly gentle miles, but upon pulling out to overtake someone, the slight tug on the wheel sensation of the back swaying out, even though it hadn't lost traction was one hell of an eye opener.
I pulled over shortly after presuming I'd magically picked up 2 flat tyres, but nothing. I tried a range of tyre pressures and although going higher helped slightly, the car still felt unfamiliar, and by this point my confidence in the tyres was shaken, and they had to go. They ruined the car for me, I didn't want to drive it anywhere, and felt like it was borderline dangerous (or I'm just a tart...
)
I got another pair of PSS, and lo and behold, despite feeling like a soft tyre in the hand, the car feels planted again. Other people get on absolutely fine with the Avons, in fact I sold them to another Monaro owner who has used them on all 4 corners since having the car and is very happy with them, so who knows, but I'm sticking with Michelins from now on
However, apparently the Monaro is quite 'fussy' with tyres, and when I went from Michelin PSS on the rear to a pair of Avons, I sold them within a few hundred miles as it just felt dangerous.
Not in a wheelspin way, as that'd be fun, but in a 'change lanes and feel the rear of the car sway to follow appreciably after the front' in a horrible pendulum motion. I'd not noticed this for the first few fairly gentle miles, but upon pulling out to overtake someone, the slight tug on the wheel sensation of the back swaying out, even though it hadn't lost traction was one hell of an eye opener.
I pulled over shortly after presuming I'd magically picked up 2 flat tyres, but nothing. I tried a range of tyre pressures and although going higher helped slightly, the car still felt unfamiliar, and by this point my confidence in the tyres was shaken, and they had to go. They ruined the car for me, I didn't want to drive it anywhere, and felt like it was borderline dangerous (or I'm just a tart...
) I got another pair of PSS, and lo and behold, despite feeling like a soft tyre in the hand, the car feels planted again. Other people get on absolutely fine with the Avons, in fact I sold them to another Monaro owner who has used them on all 4 corners since having the car and is very happy with them, so who knows, but I'm sticking with Michelins from now on
Anyone who cant feel the difference is a imbecile. Even my gf noticed something had changed when I let her drive me home with AD08s on instead of Eagle F1 2s. My 2 penneth is the sidewalls are a too soft for my car (other cars are available) but are a very good tire to live with nevertheless. Just come summer the AD08s will be going on, they just feel so much more positive...
Edited by jimbobsimmonds on Tuesday 21st January 09:49
Yep, most definitely. As someone who's first spend on a new (to me) car is in this order: tyres, suspension + bushes, brakes and brake lines.....I am very picky about tyres.
The guys at my local tyre shop (I'm lucky because a couple of them are old school mates) are not like many at tyre shops. These guys really know the tyres they sell, and are spot-on about advising all my questions on tyres. I normally end up with a set of rubber that is very well suited to the car and my style of driving - but not only that, the feedback I get through the steering wheel and chassis too.
I had a monumental cock-up once...and only once, when I moved away for a while.
I went into a local tyre shop in the new area, chosen because it was a single business type place, and not a national franchise. I often find that guys at the smaller shops are quite good at advising about tyres for a particular car, whereas nationals don't seem to know so much.
Not in this case though. I went through my specs for my Volvo S40 T4, and they recommended some Toyo T1's. I can't remember if they were 'R' or 'S' off the top of my head....
Anyway, it was shortly very clear that they were totally unsuitable for the car. Ridiculous, flexy sidewalls that deformed and deflected alarmingly
The normal firm, predictable handling (with the Bilsteins on the car) was gone, and boat-like response was the new feeling.
My fault for accepting the advice at face value. Upon getting home and doing some Googling, it seems that these are well-known for flexi sidewalls, and are recommended for small, light cars (sub 1 tonne.)
My heavier Volvo was a disaster with these on.
In the end, not being able to afford to ditch them, I just had to run 45psi all round to get a semblance of normality. Trouble was, at these pressures, the tyres were now relinquishing grip, and didn't last very long either. A blessing really.
Once they were dead, I drove the 300 mile round trip to my normal suppliers back in my old home town, and left with a fab set of Mich PS3's which were exactly what I should have got in the first place.
So - yes, I really did notice / care about it!!!
The guys at my local tyre shop (I'm lucky because a couple of them are old school mates) are not like many at tyre shops. These guys really know the tyres they sell, and are spot-on about advising all my questions on tyres. I normally end up with a set of rubber that is very well suited to the car and my style of driving - but not only that, the feedback I get through the steering wheel and chassis too.
I had a monumental cock-up once...and only once, when I moved away for a while.
I went into a local tyre shop in the new area, chosen because it was a single business type place, and not a national franchise. I often find that guys at the smaller shops are quite good at advising about tyres for a particular car, whereas nationals don't seem to know so much.
Not in this case though. I went through my specs for my Volvo S40 T4, and they recommended some Toyo T1's. I can't remember if they were 'R' or 'S' off the top of my head....
Anyway, it was shortly very clear that they were totally unsuitable for the car. Ridiculous, flexy sidewalls that deformed and deflected alarmingly
The normal firm, predictable handling (with the Bilsteins on the car) was gone, and boat-like response was the new feeling.
My fault for accepting the advice at face value. Upon getting home and doing some Googling, it seems that these are well-known for flexi sidewalls, and are recommended for small, light cars (sub 1 tonne.)
My heavier Volvo was a disaster with these on.
In the end, not being able to afford to ditch them, I just had to run 45psi all round to get a semblance of normality. Trouble was, at these pressures, the tyres were now relinquishing grip, and didn't last very long either. A blessing really.
Once they were dead, I drove the 300 mile round trip to my normal suppliers back in my old home town, and left with a fab set of Mich PS3's which were exactly what I should have got in the first place.
So - yes, I really did notice / care about it!!!
Yes and yes.
I also agree Rainsport2 are a superb wet-weather tyre.... but the sidewalls are too soft for me on (for instance) an Impreza.
With all of this 'handling' sort of malarky, there are so many variables you have to be very careful. Weight being one critical factor.
So as mentioned above, certain tyres get a fantastic reputation (on a lightweight car), you fit them to YOUR (much heavier) car, and they are rubbish (even when the tyres you fit have a higher Load Index).
And load index is not the same as sidewall stiffness. As Jon mentioned LI is the ability of the tyre to support the weight of the car, and a legal requirement. But depending on what cords/construction make up the sidewall of the tyre, it could flex/move more or less than another manufacturers tyre even with the same LI.
I also agree Rainsport2 are a superb wet-weather tyre.... but the sidewalls are too soft for me on (for instance) an Impreza.
With all of this 'handling' sort of malarky, there are so many variables you have to be very careful. Weight being one critical factor.
So as mentioned above, certain tyres get a fantastic reputation (on a lightweight car), you fit them to YOUR (much heavier) car, and they are rubbish (even when the tyres you fit have a higher Load Index).
And load index is not the same as sidewall stiffness. As Jon mentioned LI is the ability of the tyre to support the weight of the car, and a legal requirement. But depending on what cords/construction make up the sidewall of the tyre, it could flex/move more or less than another manufacturers tyre even with the same LI.
Edited by Orangecurry on Monday 20th January 22:19
Captain Muppet said:
Bill said:
jamieduff1981 said:
Yes I notice. In fairness it does need to be a fairly extreme end of the spectrum, but by way of example, I absolutely hated the internet hero that was the Toyo T1R. There is a balance to be struck though. Rock hard tyres aren't ideal either.
I likeT1Rs because they give a much gentler break away when they start to slide. Great for gentle breakaway, terrible for cornering grip and wear.
The good news was that they are quieter and have slightly a better ride and, probably, higher ultimate grip level. But there's no pleasure in pushing them as they squish & squirm as soon as you turn the wheel and get some lateral loading into them: The steering feel and precision has been knocked down a significant amount. The phrase "More grip than handling" would suit them.
I did notice it took longer for my car to respond when I switched to Bridgestone A001's from the um... slightly mixed bag of whatever my car had on before (it was a long time ago!) but I figured as slightly wintery-er tyres with tractor like tread it was bound to happen.
The other car I use is on the same rubber (different size though) so I'm well adapted to 'em...
The other car I use is on the same rubber (different size though) so I'm well adapted to 'em...
SturdyHSV said:
However, apparently the Monaro is quite 'fussy' with tyres, and when I went from Michelin PSS on the rear to a pair of Avons, I sold them within a few hundred miles as it just felt dangerous.
Not in a wheelspin way, as that'd be fun, but in a 'change lanes and feel the rear of the car sway to follow appreciably after the front' in a horrible pendulum motion. I'd not noticed this for the first few fairly gentle miles, but upon pulling out to overtake someone, the slight tug on the wheel sensation of the back swaying out, even though it hadn't lost traction was one hell of an eye opener.
Exactly my experience, as written here:Not in a wheelspin way, as that'd be fun, but in a 'change lanes and feel the rear of the car sway to follow appreciably after the front' in a horrible pendulum motion. I'd not noticed this for the first few fairly gentle miles, but upon pulling out to overtake someone, the slight tug on the wheel sensation of the back swaying out, even though it hadn't lost traction was one hell of an eye opener.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Changed 2 front Bridgestone Turanza ER 300 (H rated) for 2 Dunlop Sport BluResponse (V rated) - still with Bridgestones on the back.
The difference was quite an eye opener!
It's only after speaking to a Dunlop engineer that I find the tyre wall makeup is substantially softer than the Bridgestone - which in turn results in the 'see-sawing' effect.
I think that some clear measurement indication should be given so that buyers can easily compare like for like tyres.
Perhaps something along the lines of a 'jelly system':
Edited by Fastra on Monday 27th January 15:00
Puddenchucker said:
Captain Muppet said:
Bill said:
jamieduff1981 said:
Yes I notice. In fairness it does need to be a fairly extreme end of the spectrum, but by way of example, I absolutely hated the internet hero that was the Toyo T1R. There is a balance to be struck though. Rock hard tyres aren't ideal either.
I likeT1Rs because they give a much gentler break away when they start to slide. Great for gentle breakaway, terrible for cornering grip and wear.
The good news was that they are quieter and have slightly a better ride and, probably, higher ultimate grip level. But there's no pleasure in pushing them as they squish & squirm as soon as you turn the wheel and get some lateral loading into them: The steering feel and precision has been knocked down a significant amount. The phrase "More grip than handling" would suit them.
In the old days of treaded racing tyres, you could tell how fast a driver was by the look of his tyres, at rest in the pits.
Yes the tread blocks bend over, so that at rest, after a few laps the tread would have a saw tooth appearance, with the top of each block worn at an angle. It was flat on the road, when cornering, if the bloke could drive hard enough. The bloke who never got to 7 tenths would still have flat tread, the bloke who was seconds quicker driving at 9 tenths would have the typical saw tooth appearance. The side walls of those tyres were so soft, you could damn near cut them with a fingernail.
I thought I had better add, I'm talking about F1 & F2 cars here.
That being said, not even a driving god would drive that hard on the public road, so racing rubber was, & still is, unsuitable for "normal" road use.
On the sidewall thing, I have just replaced the no longer available in 13" Pirelli front tyres on my TR7. They were 6 years old, & getting too hard.
I was really worried about replacements, as no top manufacturers are still making tyres in 13", & these cars don't respond to low profile tyres.
I fitted a couple of Kumho RH17 [185 70 R13], which are only recommended as a touring tyre. I am pleasantly surprised. They ride better, are quitter, & the steering is so much lighter, it is as if I have fitted power steering.
More importantly, it is quicker through my private slalom course. Although the turn in is not as sharp, the car is better balanced by the fourth change in direction. This makes it only a little slower through them than my S2000.
It is also quicker through my favorite 110Km/H sustained down hill negative camber curve. This is also surprising, as I get the impression it is wanting to understeer, but doesn't. I guess I am being fooled by the lighter steering, & the fact a little more steering wheel is required.
I won't be fitting them to the S2000, but will probably put some on the 330 BHP TR8 shortly.
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