(M400) tyre wheels etc advice please
Discussion
collected my new toy today black m400 currently has black comp wheels fitted but also came with original alloys but with no tyres where is the best place to source tyres ?toyo R888 or any other better options advice would be good as i am outting the original alloys back on so may consider selling the comp alloys which all have toyo R888's fitted if anyone is interested let me know also does anyone know of a set of m400 centre wheel caps or where they can be sourced many thanks sean
Congrats on the M400 
I just recently was discussing tyre options and how lightweight tyres/rims affect the cars power delivery to the wheels.
http://www.pistonheads.com/xforums/topic.asp?h=0&a...
Toyo R888 are a very grippy tyre, when i got them fitted wheel spin was in low gears was virtually eliminated, but i'm not suprised seen as though they are a heavy tyre and increase rotational inertia by 10%, each Toyo tyre like for like weighs 1.5kg more than a PS3.
Imagine a hammer, the more weight you put on the end the more difficult it is to rotate it, so the tyre being the most outer part of the wheel is like the weight on the end of the hammer.
I have done 10000km on The Toyo(2 sets on the back) in my opinion are only good for track, for road use they are very noisy, wear fast,terrible feedback, no good in the wet, tram line and you lose ride comfort, all for the price of increasing lateral grip in the dry.
I just recently was discussing tyre options and how lightweight tyres/rims affect the cars power delivery to the wheels.
http://www.pistonheads.com/xforums/topic.asp?h=0&a...
Toyo R888 are a very grippy tyre, when i got them fitted wheel spin was in low gears was virtually eliminated, but i'm not suprised seen as though they are a heavy tyre and increase rotational inertia by 10%, each Toyo tyre like for like weighs 1.5kg more than a PS3.
Imagine a hammer, the more weight you put on the end the more difficult it is to rotate it, so the tyre being the most outer part of the wheel is like the weight on the end of the hammer.
I have done 10000km on The Toyo(2 sets on the back) in my opinion are only good for track, for road use they are very noisy, wear fast,terrible feedback, no good in the wet, tram line and you lose ride comfort, all for the price of increasing lateral grip in the dry.
R0162 said:
Imagine a hammer, the more weight you put on the end the more difficult it is to rotate it, so the tyre being the most outer part of the wheel is like the weight on the end of the hammer.
At the risk of you shouting at me again, not quite.Rotational to static interia effect of a tire is easily calculated by using the moment of interia equiation
I = SUM(m(i) r(i)^2)
which, when you want to know it in weight terms (using the decresing partical size approximation)
I = 1/2 mr^2
So, for a 265/35R18 you have a diameter of 18" = 458mm or 0.458m
You state the tyre is 15% lighter and saves 1.5kg, so I'll take the whole tyre is therefore 10kg.
I(1) = 1/2 10 x 0.458^2 = 1.04882
I(2) = 1/2 8.5 x 0.458^2 = 0.891497
Ergo, a 15% drop in tyre weight reduces intertia by, wait for it, (1.04882 - 0.891497)/1.04882 - 15%.
I could also point out that of course 1kg of rotational interia is equal to just 4kg of static interia, and hence on a 1100kg car, 4 tyres 1.5kg lighter would save you just 16kg of static interia weight, or just 1.454%.
This doesn't change the fact that it will improve steering response etc., but it really will do jack all to the performance of your car.
J
sean j g said:
hi thanks car is great with regard to the tyres where is the best/cheapest place for me to source these tyres are the ps3's in your opinion the better option for me as i dont intend to do many track days so looking for the best option for mainly road use many thanks sean.
If you want "Corsa's" (i.e. track day tyre that is road legal) then you current choice is P Zero Trofeo. They are "better" than Corsa'shttp://www.silverlinewheels-tyres.com/motorsport/t...
Outside of that, there are loads of choices.
Rears (265/35R18)
Yoko AD08 / A048 R
Toyo T1 Sport / T1R Proxies/R888/R1R
Goodyear Eagle F1
Pirelli Pzero Rosso
Vredestein Ultrac Sessanta
Falken FK452 / ZE912
Federal 595 RS-R (my next set)
Fronts (225/40 R18)
Yoko AD048/A048 R
Toyo C1-S / T1 Sport/ T1-R / R888 / R1R
Goodyear Eagle F1
Pirelli Pzero Rosso
Vredestein Ultrac Sessanta / Ultrac Cento
Falken FK452 / ZE912
Federal 595 RS-R
http://www.camskill.co.uk is a good site to look at the options.
J
No i have never SHOUTED at you Justin
Before i posted i did some research on the internet, i googled "how tyre weights affect performance" then i read about "rotational inertia" so then i googled that, it seems the heavier the wheel/tyre is the more turning force/torque is required to rotate it, and this effect is amplified the more you move from the centre of rotation, so if you were to rotate a hammer from the base of the handle, then the head of the hammer is the equivalent of the tyre.
I always say to exagerate things to simplify, think of a hammer with a tiny light head and one with a big 10kg heavy head, would one require more force than the other to rotate?
I'm not going to pretend to be an expert on this subject, its just that everything i read seems to disagree with what you said, in that tyre weight does directly affect performance because it takes less force to spin the wheel, + i read (rightly or wrongly) 2 lbs reduction in weight on the tyre on 18" rims is the equivalent of reducing the static weight of the car by 200lbs.
I'm guessing thats the equivalent of carrying a medium sized rugby player, or a rather large woman.
Don't get me wrong Justin i do appreciate your input and knowledge, i like to gather as much information as possible.
With regards to tyre widths i have ordered 275/35/18 rear and 235/40/18 front i am a bit worried about straying from stock sizes, i would appreciate your advice on this, should i stick to stock sizes? its not too late to change the order.
Before i posted i did some research on the internet, i googled "how tyre weights affect performance" then i read about "rotational inertia" so then i googled that, it seems the heavier the wheel/tyre is the more turning force/torque is required to rotate it, and this effect is amplified the more you move from the centre of rotation, so if you were to rotate a hammer from the base of the handle, then the head of the hammer is the equivalent of the tyre.
I always say to exagerate things to simplify, think of a hammer with a tiny light head and one with a big 10kg heavy head, would one require more force than the other to rotate?
I'm not going to pretend to be an expert on this subject, its just that everything i read seems to disagree with what you said, in that tyre weight does directly affect performance because it takes less force to spin the wheel, + i read (rightly or wrongly) 2 lbs reduction in weight on the tyre on 18" rims is the equivalent of reducing the static weight of the car by 200lbs.
I'm guessing thats the equivalent of carrying a medium sized rugby player, or a rather large woman.
Don't get me wrong Justin i do appreciate your input and knowledge, i like to gather as much information as possible.
With regards to tyre widths i have ordered 275/35/18 rear and 235/40/18 front i am a bit worried about straying from stock sizes, i would appreciate your advice on this, should i stick to stock sizes? its not too late to change the order.
R0162 said:
I always say to exagerate things to simplify, think of a hammer with a tiny light head and one with a big 10kg heavy head, would one require more force than the other to rotate?
Two things. If it was a 1kg and 10kg hammer, then it would take 10 times the force. The main point though is relative to the force being applied to actually move the car forward, the mass of the wheel bears little relationship to the mass of the car being moved forward.So, the weight of the tyre is important for the reaction of the suspension to bumps etc, but bears little bearing on the actual overall acceleration/deacceleration of the car.
As on the other thread though, if you change the tyre you potentially would need to adjust the suspension. The difference though of 1.5kg to the tyre, given the whole thing probably is in the 20kg+ range, again won't make a dramatic difference.
If you want to really remove weight, the alloys should be your main focus, then the hubs, and finally the control arms / dampers.
J
joust said:
So, the weight of the tyre is important for the reaction of the suspension to bumps etc, but bears little bearing on the actual overall acceleration/deacceleration of the car.
J
J,J
Don't forget that the tyres rotate quite a lot! and changing their rotational speed requires force (as shaft torque or the tyre contact patch), which has to come from the engine/brakes. So yes, the lower mass of the tyre has a bigger impact on performance than just it's static weight.
Also, as you know rotational inertia is proportional to mass at the square of the radius, so taking the weight off at the tyre will have a bigger effect on inertia than the same weight off the hubs.
It's the same reason that a heavy flywheel can affect first gear vehicle acceleration way more than it's pure mass would in terms of linear acceleration.
As always, lower weight equals better performance........
YellowShed
YellowShed said:
[stuff]
As always, lower weight equals better performance........
All agreed.As always, lower weight equals better performance........
Not sure 1.5kg would make that much difference even given the above as compared to the rotational mass of the alloy wheel itself, hub and rest of the tyre (which also increases as you outline) you are still in a game where you are just looking at a straight forward percentage increase to the percentage difference.
But wasn't it Chapman said his approach was to "add lightness" - a fine idea.
joust said:
ll agreed.
Not sure 1.5kg would make that much difference
Its on the outer most part of the wheel and makes a 10% difference, reducing rotational inertia by 10% when comparing to Toyo R888, in theory!!Not sure 1.5kg would make that much difference
I decided to Myth bust this one( to a certain extent) with regards to weights, my friends all thought i was crazy as per usual and were laughing at how pedantic i was being, because they were all saying just look up the weights on the internet, but i like to check if the information on the internet is correct and i wanted to get an accurate idea of whether i had reduced or increased weight in RL.
Michelin PS3 275/35/18 weighed 12.2 kg that is 27 lbs
235/40/18 weighed 9.8 kg that is 21.5 lbs
These above weights are for new, the below weights are for the old Toyo i took off.
Toyo R888 265/35/18 weighed 10.6kg that is 24 lbs(internet 28 lbs new)
225/40/18 weighed 9.2kg that is 20.2 lbs(internet 23 lbs new)
So from old to new i have actually increased weight and rotational inertia by 10%, also take into account that the wider Michelin do not put as much rubber onto the tarmac, each michelin had 1cm less of actual contact surface than the toyos which are almost 1.5cm narrower.
But when the Michelins are worn to the same extent they "may" well be lighter, i did not have new Toyos to make a comparison.
So i hope your right Justin, otherwise i have just made my problem worse and will have to upgrade the clutch or detune the car
I will do some P box times in order to see exactly what the difference is to acceleration times.
Performance aside, the PS3's have completely transformed the ride with regards to noise and comfort and that difference is immediately noticable, although the steering did not feel as good.
The Toyos on my car were dated 2006, the Michelin were dated 2nd week of 2011, when the rubber gets old can it dry out? I.e lose weight by moisture? or can they only lose weight by shedding rubber?
I bought some new wheels for my pushbike recently, I had a long discussion with the guy who owns the shop, about which wheels to select as everyone gets obsessed with weight, the out come was, that the weight wasn't critical, what was is where the weight is, if most is in the hub that's ok, however if most is in the rim it's rubbish.
once I thought about it I decided it was common sense.
once I thought about it I decided it was common sense.
joust said:
t the risk of you shouting at me again, not quite.
Rotational to static interia effect of a tire is easily calculated by using the moment of interia equiation
I = SUM(m(i) r(i)^2)
which, when you want to know it in weight terms (using the decresing partical size approximation)
I = 1/2 mr^2
So, for a 265/35R18 you have a diameter of 18" = 458mm or 0.458m
You state the tyre is 15% lighter and saves 1.5kg, so I'll take the whole tyre is therefore 10kg.
I(1) = 1/2 10 x 0.458^2 = 1.04882
I(2) = 1/2 8.5 x 0.458^2 = 0.891497
Ergo, a 15% drop in tyre weight reduces intertia by, wait for it, (1.04882 - 0.891497)/1.04882 - 15%.
I could also point out that of course 1kg of rotational interia is equal to just 4kg of static interia, and hence on a 1100kg car, 4 tyres 1.5kg lighter would save you just 16kg of static interia weight, or just 1.454%.
This doesn't change the fact that it will improve steering response etc., but it really will do jack all to the performance of your car.
J
And you told me, on the 'Rota wheels' thread, that you wasn't a numbers man!! Rotational to static interia effect of a tire is easily calculated by using the moment of interia equiation
I = SUM(m(i) r(i)^2)
which, when you want to know it in weight terms (using the decresing partical size approximation)
I = 1/2 mr^2
So, for a 265/35R18 you have a diameter of 18" = 458mm or 0.458m
You state the tyre is 15% lighter and saves 1.5kg, so I'll take the whole tyre is therefore 10kg.
I(1) = 1/2 10 x 0.458^2 = 1.04882
I(2) = 1/2 8.5 x 0.458^2 = 0.891497
Ergo, a 15% drop in tyre weight reduces intertia by, wait for it, (1.04882 - 0.891497)/1.04882 - 15%.
I could also point out that of course 1kg of rotational interia is equal to just 4kg of static interia, and hence on a 1100kg car, 4 tyres 1.5kg lighter would save you just 16kg of static interia weight, or just 1.454%.
This doesn't change the fact that it will improve steering response etc., but it really will do jack all to the performance of your car.
J
Adrian W said:
that the weight wasn't critical, what was is where the weight is, if most is in the hub that's ok, however if most is in the rim it's rubbish.
once I thought about it I decided it was common sense.
Totally agree Adrian, this is what my research has led me to believe, if you get a lightweight alloy, it is the rim that needs to be light, the hub can be heavy it desnt really matter because it is local to the centre.once I thought about it I decided it was common sense.
The weight of the tyre being the most outer part is the worst place to add weight, i.e. adding 1kg to the hub is nothing, adding 1kg to the weight of a tyre gets amplified according to distance from the centre with regards to size of alloy( Justin please add clever equation here which i do not understand)
I think this is why putting big alloys is the ultimate way to decrease performance and you can not just put a lightweight alloy and think this will even out a heavy tyre, because all the weight reduction on the alloy may be local to the centre.
Dymags with carbon fibre rim, now i understand what the advantages are, weight reduction where it matters.
Adrian W said:
I bought some new wheels for my pushbike recently, I had a long discussion with the guy who owns the shop, about which wheels to select as everyone gets obsessed with weight, the out come was, that the weight wasn't critical, what was is where the weight is, if most is in the hub that's ok, however if most is in the rim it's rubbish.
once I thought about it I decided it was common sense.
Yep - it's a square law (I=1/2mr^2) and hence as you double the distance of the mass the intertia goes up by a factor of four.once I thought about it I decided it was common sense.
Of course for a fat bloke like me the wheels on the bike make little difference
Blu3R said:
And you told me, on the 'Rota wheels' thread, that you wasn't a numbers man!!
Unfortunatly did an engineering degree at Brunel. The first 2 years was essentially a maths degree with additional engineering thrown on top, and I spent my life having to remember almost every mechanical and electrical equation there ever was.Joy it wasn't.
I compounded the mistake by going to work for GEC Hirst Research in the Long Range Research Lab afterwards, and then spent most my time buidling computers and the associated programmes to crunch said equations.
I saw the light and now just swan around looking important
R0162 said:
So from old to new i have actually increased weight and rotational inertia by 10%, also take into account that the wider Michelin do not put as much rubber onto the tarmac, each michelin had 1cm less of actual contact surface than the toyos which are almost 1.5cm narrower.
So i hope your right Justin, otherwise i have just made my problem worse and will have to upgrade the clutch or detune the car
[and then went on to say]
Performance aside, the PS3's have completely transformed the ride with regards to noise and comfort and that difference is immediately noticable, although the steering did not feel as good.
I think that might show that the compound and the 'feel' of the tyre is probably as important as it's raw weight. You could do the old "just drive it" approach to development that Lee Noble uses!So i hope your right Justin, otherwise i have just made my problem worse and will have to upgrade the clutch or detune the car
[and then went on to say]
Performance aside, the PS3's have completely transformed the ride with regards to noise and comfort and that difference is immediately noticable, although the steering did not feel as good.
Gassing Station | Noble | Top of Page | What's New | My Stuff