Toyo R888 Vs Michelin PS3
Discussion
I have ordered a set of Michelin PS3 to replace my old Toyo R888 as a road tyre.
I needed something a bit more road friendly, more comfortable over bumps, less noise etc..the R888 were very noisy tyres.
Anyway one thing that sold me the PS3's was the weight difference, like for like on sizes you save 1.5kg on each tyre, i had not thought of tyre weights until recently, people spend alot of money on lightweight alloys but nobody ever seems to mention the weight of the tyres.
I'm not sure if they are good for track days but for everyday road i am hoping they are going to be good, will surely be an improvement in all areas with the exception of dry grip.
Anybody else tried them yet? Anybody know how long they take to run in?
I needed something a bit more road friendly, more comfortable over bumps, less noise etc..the R888 were very noisy tyres.
Anyway one thing that sold me the PS3's was the weight difference, like for like on sizes you save 1.5kg on each tyre, i had not thought of tyre weights until recently, people spend alot of money on lightweight alloys but nobody ever seems to mention the weight of the tyres.
I'm not sure if they are good for track days but for everyday road i am hoping they are going to be good, will surely be an improvement in all areas with the exception of dry grip.
Anybody else tried them yet? Anybody know how long they take to run in?
you're right. never really think about tyre weight but as you've proved a substantial difference. you would have thought there wouldn't be that much difference between some slightly different shaped strips of rubber!!! ha.
I wonder if saving 1.5kg off a tyre weight has more of an improvement than saving the same weight off a wheel. the weight of a wheel being 'upstream' of the spring effect of the tyre itself and some of the tyre weight being directly on the ground and possibly considered unsprung! hmmm, not sure. obviously removing any weight has to be a good thing so long as you dont move too far away from what the spring dampers are designed for.
cheers
James
Just been reading up on this to get a bit educated and it appears that a light tyre being the most outer part of the wheel has a big effect on rotational inertia, so when it comes to the weight of your wheels with regards to the ammount of force it takes to rotate them the tyre is the most important part.
With the PS3 tyres rotational inertia is reduced by 10% over the Toyo R888, if i understand correctly that also means the wheel can be rotated using 10% less power, if it is right then that is quite a performance increase due to a set of tyres.
What is the real affect of this? I mean could you reduce power by 10% and still gain the same acceleration values?
Now i understand why the Hoosiers, use a fibreglass weave to reinforce their tyres, it's to reduce weight.
The lighter tyres also reduce the unsprung weight but being a small ammount i do not think it would make a significant difference to the ride or response of handling, although still no doubt measurable.
With the PS3 tyres rotational inertia is reduced by 10% over the Toyo R888, if i understand correctly that also means the wheel can be rotated using 10% less power, if it is right then that is quite a performance increase due to a set of tyres.
What is the real affect of this? I mean could you reduce power by 10% and still gain the same acceleration values?
Now i understand why the Hoosiers, use a fibreglass weave to reinforce their tyres, it's to reduce weight.
The lighter tyres also reduce the unsprung weight but being a small ammount i do not think it would make a significant difference to the ride or response of handling, although still no doubt measurable.
R0162 said:
What is the real affect of this? I mean could you reduce power by 10% and still gain the same acceleration values?
Nope, see my post on the other thread where you reference this.R0162 said:
The lighter tyres also reduce the unsprung weight but being a small ammount i do not think it would make a significant difference to the ride or response of handling, although still no doubt measurable.
Unfortunatly that is exactly where the difference is felt.Inertia is the resistance to movement and is directly proportional to weight (F=MA).
Ergo, if you reduce mass, you reduce intertia.
So, if you had a wheel assembly of, say, 40kg, then the force needed to stop it moving upwards at, say 1m/s/s would be 40N. Drop the weight by 1.5kg and the force drops by exactly the same amount.
Another important ratio is the "sprung" to "unsprung" weight. The heavier the sprung weight (i.e. the body/engine etc. that hang off the wheels), the less the car will want to move around due to the inverse of the above. This natural damping effect counteracts the un-sprung weight argument.
This is why a heavier car can somethings ride "better" than a lighter car, because a heavy car has a better ratio.
This therefore means that reducing unsprung weight on a Noble is a very good thing to do, as the main bulk of the car is so light (relative to other sports cars). A 1.5kg reduction in tyres on a Noble will probably be noticed more than a similar tyre change on a Porsche.
J
joust said:
This therefore means that reducing unsprung weight on a Noble is a very good thing to do....
Maybe, maybe not. Problem is if the suspension is setup for a certain unsprung weight, which it generally is, changing it up or down can have unforeseen consequences. On the track you'd bet it was almost always a good thing. On a bumpy B road...well, that's what testing and adjustable suspension's for!R0162 said:
ok what affect is changing to 275/35/18 and 235/40/18 going to have, nothing complicated please, should i stick to the stock sizes?
Might rub on lock I guess and bigger fronts may induce more oversteer if they overpower the larger rears. That'll depend on camber angles though. If you're having clutch slip and you put more grip at the back, you know what's going to happen....R0162 said:
And should i stick with 225 on the front?
Hard to say as really it's how you like the car balanced. To be honest you've mostly hot roads and seem to be picking soft/sticky tyres so grip isn't going to be lacking. Unless you stiffen it right up you'll be running around on the bump-stops at high G.As for the rears, again depends what you want. It's wheelspin that's saving your drivetrain in reality. You've already found by adding weight to the car (and probably balancing it with a passenger) to can spin the clutch as you've probably increased the rear grip.
ThatPhilBrettGuy said:
Maybe, maybe not. Problem is if the suspension is setup for a certain unsprung weight, which it generally is, changing it up or down can have unforeseen consequences. On the track you'd bet it was almost always a good thing. On a bumpy B road...well, that's what testing and adjustable suspension's for!
Agreed. As above given forces change you would need to have adjustable dampers, and if really keen, potentially change the spring rates.J
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