Lighter Wheels?
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Sacrilicious
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I've given this problem some thought too, and it really comes down to how much you're willing to pay for the wheels. Our stock wheels weigh 24lb each...combined with the 24lb Potenza RE050A tires, that gives us 48lb of unsprung weight in each wheel + tire package. Now, you can definitely drop a decent amount of weight from this by getting 3rd party wheels...in fact, 15-17lb per wheel is a pretty achievable weight to shoot for. The problem lies in what you're willing to pay for this weight, though. If you are only willing to spend 150-200 per wheel, then you can get these wheels, but it will be a cast alloy wheel made by companies like Kazera, Kosei, etc. which will likely be pretty easy to bend. Now, if you're willing to pay 400-600 per wheel, you will be able to move up to forged wheels which will not only weight 15-17lbs, but will also be very strong as well.
So, if you live in an area where there aren't potholes and you will never hit a bump or curb, then it's perfectly safe to go ahead and get the cheap light wheels. Unfortunately, most people live in places where they have to choose between spending a lot initially on wheels to handle the thumps, or risking constant wheel replacements due to dents made by the roads they drive on. Keep in mind that our stock wheels cost $490 each from the dealership, but I've heard that they are pretty darn strong...they'd BETTER be with 24lb of alloy!
EDIT: our stock wheels are cast alloy, btw...they're just $490 each cause Mazda is having its way with us...=/
Oh, and I forgot to mention that lighter wheel+tire means:
1. less load on the suspension when you hit a bump.
2. more power applied to the road because your rotational weight (what is actually rotating when you apply power) is lower.
3. better traction over non-flat surfaces.
So, if you live in an area where there aren't potholes and you will never hit a bump or curb, then it's perfectly safe to go ahead and get the cheap light wheels. Unfortunately, most people live in places where they have to choose between spending a lot initially on wheels to handle the thumps, or risking constant wheel replacements due to dents made by the roads they drive on. Keep in mind that our stock wheels cost $490 each from the dealership, but I've heard that they are pretty darn strong...they'd BETTER be with 24lb of alloy!
EDIT: our stock wheels are cast alloy, btw...they're just $490 each cause Mazda is having its way with us...=/
Oh, and I forgot to mention that lighter wheel+tire means:
1. less load on the suspension when you hit a bump.
2. more power applied to the road because your rotational weight (what is actually rotating when you apply power) is lower.
3. better traction over non-flat surfaces.
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Number 1...no problem, I can see that.
Number 2 is technically true, but I doubt you would notice much difference because you aren't reducing the weight that much. After all, if the 48 lbs tire / wheel combo get reduced to say 40 lbs a tire / wheel combo, you still are pulling 3100+ lbs! (plus the driver and anything else you have it the car)
If these tires were driving a low weight system (say at a high velocity) then it would make a significant difference. (Also...we are still torque limited in 1st and 2nd gears anyway...even with our heavier tires.)
Could you explain number 3 a little better? I am pretty good with physics, but I might just be missing this one.
Sacrilicious
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ya, number 2's gain would be pretty darn minor. i mean, you figure at best we get ~220 of our engine hp at the wheel as it is, so the most we could POSSIBLY improve is by 40hp or so, and that's not even taking into account the fact that power gets lost due to friction and whatnot in the transmission. in the end, reducing your wheel+tire weight by 8lb will probably net you on the order of the very low single digits...most of your "improvement" will likely be psychological...^_^;
as far as number 3 goes, what happens is that when you hit a bump, it bounces your wheel + tire up, which reduces or even eliminates the traction you have with the road for a split second before your suspension pushes it back down. at this point, it becomes a matter of momentum. if you have less bouncing weight, it will take less effort and time for the suspension to push it back into place (planting you back into firm contact with the road again). due to this effect, you will see better handling around turns that aren't perfectly flat...not to mention an lighter load on your suspension itself. now, i'm not saying that this is gonna make us FLY around bumpy corners, but there will definitely be an effect.
EDIT: a good analogy for what happens in number 3 is that little skip to the side you feel when you hit a bump as you dig at high speed through a heavy turn. the lighter your wheel + tire combo is, the less you will actually skip.
as far as number 3 goes, what happens is that when you hit a bump, it bounces your wheel + tire up, which reduces or even eliminates the traction you have with the road for a split second before your suspension pushes it back down. at this point, it becomes a matter of momentum. if you have less bouncing weight, it will take less effort and time for the suspension to push it back into place (planting you back into firm contact with the road again). due to this effect, you will see better handling around turns that aren't perfectly flat...not to mention an lighter load on your suspension itself. now, i'm not saying that this is gonna make us FLY around bumpy corners, but there will definitely be an effect.
EDIT: a good analogy for what happens in number 3 is that little skip to the side you feel when you hit a bump as you dig at high speed through a heavy turn. the lighter your wheel + tire combo is, the less you will actually skip.
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#2 and #3 and kind of related - basically, its easier to move something thats lighter. the lighter the wheels-tires, the easier it is for the engine to get them to rotate, and the easier it is for the suspension to move them up and down. better acceleration, and better handling.
Sacrilicious
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the difference that you're probably feeling is that the snow tires are really flexible. it's literally like driving on blocks of jelly (relatively speaking) when compared to the summer tires, which are firmer and lower profile. effective snow tires should be high profile and made from the proper materials and treading so that it (treads and actual sidewall) will flex and twist to maintain traction with that cold, wet stuff...;o also, you tend to deflate your tires down a few lbs of pressure so that your snow tires can form the correctly shaped footprint. with summer tires, you're striving for a very wide (sideways) footprint, whereas with snow tires, you're lengthening the depth (front-to-back) of your contact patch.
as a net effect, the summer tires will allow you to feel attached to the road and corner quickly and responsively whereas the snow tires will squish all around and kill your ability to turn in warm, dry weather.
Sacrilicious
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ya, the slower thing makes sense too, cause you don't have nearly as much dry traction with the winter tires.
thats not it either - its rotational inertia, newton's laws of motion stuff - you know the one, an object in motion tends to stay in motion / object at rest tends to stay at rest - coupled with the "Force = Mass x Acceleration" thing, where you increase the mass (weight of the wheel) you increase the amount of force required to get it to accelerate. it has nothing to do with traction. all of this is why lighter wheels are better.
Sacrilicious
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the 5 lbs from the wheels + tires is not what's making the huge difference in acceleration that you're seeing. here's some numbers:
our engines make 263 hp...the most you will likely see at the wheels is about 220 hp. this means we have 43 hp lost in the transmission, gears, etc. in addition to what we lose due to power wasted turning the wheel + tires of our car. now, our wheels + tires already weigh 48 lbs, so dropping 5lb is about 10% savings on weight. so, assuming that ALL of that 43 hp was lost in turning our wheels + tires (which it's not, since friction in the transmission, gears, etc. kills a good percentage of that power in reality), it leaves us with a theoretical gain of about 4-5 hp put onto the ground. i highly doubt that your noticeable loss of acceleration is from that.
EDIT: forgot to mention...5lbs per wheel also means 20lb in overall weight...this will save us less than 1% of our total weight, which is an insignificant gain for all intents and purposes.
basically, the majority of the performance hit you're getting when going from summer -> winter tires is from loss of traction.
our engines make 263 hp...the most you will likely see at the wheels is about 220 hp. this means we have 43 hp lost in the transmission, gears, etc. in addition to what we lose due to power wasted turning the wheel + tires of our car. now, our wheels + tires already weigh 48 lbs, so dropping 5lb is about 10% savings on weight. so, assuming that ALL of that 43 hp was lost in turning our wheels + tires (which it's not, since friction in the transmission, gears, etc. kills a good percentage of that power in reality), it leaves us with a theoretical gain of about 4-5 hp put onto the ground. i highly doubt that your noticeable loss of acceleration is from that.
EDIT: forgot to mention...5lbs per wheel also means 20lb in overall weight...this will save us less than 1% of our total weight, which is an insignificant gain for all intents and purposes.
basically, the majority of the performance hit you're getting when going from summer -> winter tires is from loss of traction.
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yeah it is, and like i said, i don't have a 3
have you ever driven a car that had two sets of wheels, one lighter than the other? you'd be surprised how much of a difference lighter wheels make. miata drivers have been know to notice down to a 2lbs difference on wheel weights. and, with 48lbs wheels, you should EASILY be able to drop up to 15lbs per corner - thats a HUGE difference.
Young Roids
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Young Roids
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How much do those MAZDASPEED ones weigh? The MAZDASPEEDS are Rays so they are the same company as Volks and Volks are one of my favorite wheel brands as well as racing hart wich is yet another RAYs company. Basically all the RAYs brand are top of the line. I think Enkei is top of the line as well but they just have better prices.
Sacrilicious
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- Cosmic Blue MS3 of hawtness!
yes, there's definitely more factors than traction, but when you swap out winter tires + wheels and put on summer tires + wheels and blame the lost performance on the weight, something just doesn't make sense.
keep in mind, i'm only saying that i disagree with you on the acceleration point. the bottom line is that the TOTAL power lost due to the rotational weight on the mazdaspeed is probably no more than 20hp...so that leaves your total possible gain at 20hp assuming your wheels + tires weight 0 lbs. dropping 15lbs from our wheel + tire is a pretty darn expensive deal here. we're talking a whole new set of wheels + tires for what? a total gain of 6-7hp? hell, if that's all your getting for added acceleration out of the deal, you may as well spend 250 on the MS CAI and get more power out of the deal.
miata owners notice 2lb differences because their cars weight a LOT less than the MS3, and their wheel + tire already weights about 10-15lb less than ours. also, they have less power to begin with and quite honestly, i'm willing to bet that for the vast majority of people, that difference than feel is completely psychological. i mean, come ON now...what normal driver feels the difference between a 6.0 and 5.9 run to 60?
the bottom line is you cannot compare a winter combo and a summer combo and come up with the conclusion that the 5lb difference in weight is what makes the most difference between the two...
keep in mind, i'm only saying that i disagree with you on the acceleration point. the bottom line is that the TOTAL power lost due to the rotational weight on the mazdaspeed is probably no more than 20hp...so that leaves your total possible gain at 20hp assuming your wheels + tires weight 0 lbs. dropping 15lbs from our wheel + tire is a pretty darn expensive deal here. we're talking a whole new set of wheels + tires for what? a total gain of 6-7hp? hell, if that's all your getting for added acceleration out of the deal, you may as well spend 250 on the MS CAI and get more power out of the deal.
miata owners notice 2lb differences because their cars weight a LOT less than the MS3, and their wheel + tire already weights about 10-15lb less than ours. also, they have less power to begin with and quite honestly, i'm willing to bet that for the vast majority of people, that difference than feel is completely psychological. i mean, come ON now...what normal driver feels the difference between a 6.0 and 5.9 run to 60?
the bottom line is you cannot compare a winter combo and a summer combo and come up with the conclusion that the 5lb difference in weight is what makes the most difference between the two...
I have to agree...there is no way that minor change in weight would affect your acceleration that much. The overall weight change is too minor. The torque rotating a tire not touching the ground that weighs 10 lbs lighter than another is major...rotating a tire that is on the ground (with good traction) that has to impart velocity to a 3100+ lbs object that is directly connected to it...not going to matter much.
Thanks for the clarification on number 3....makes sense now that I think about it more.
Sacrilicious
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i agree that enkei makes very nice wheels, but the reason why the RPF1 is so much more affordable than the Volk is because the Volk is a forged wheel. they're a significantly stronger wheel than the RPF1, and that's what you're paying for. you just can't cast alloy wheels nearly as strong as you can forge them. with cast wheels, you're much more vulnerable to potholes and whatnot.
