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Old 01-31-2013, 01:01 PM   #15426
ans2k
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Originally Posted by Dirt Bringer View Post

Well 7.5 should be good enough. I was considering going 18 (obviously with appropriate tires), but honestly I was thinking that maybe a lighter wheel would actually increase performance a lot more than a larger one. How much performance can be gained by going with a ~15lb set of wheels and losing however many pounds at each wheel compared to stock?
Man I have no idea what the crap the guy above me was saying. Adverse effects? There is none or just one. Money on how much the rims cost. Decrease unsprung weight decreases the rotational torque. No time to explain physics or moment of inertia. This will improve handling and acceraltion. Will this improve fuel economy? Only when accelerating but you may lose some while curising. Because there is less mass to keep the wheels in motion. Losing 60 pounds of unsprung weight has a larger effect than just losing 60 pounds off the body of the car. Going with a larger rim has a good and bad effects. Good is that you can use a skinnier tire which could have stiffer side walls for a sharper turn in. Bad is that that stiff side wall makes for a harsher ride and a lelarger rim pushes the moment of inertia father from the center of rotation which increase the rotational torque. Which could counter act the weight that you loss. If you went with 15 pound rims, you could gain some performance. Depending what tires you go with. But it is hard to give a definite answer on how much you can gain. There is no number I can give you. 7.5 inch wide is good enough for a lot of things. Your car isnt a track monster or drag beast. The only thing I can say really is that having said what I just said, get whatever makes you happy because no matter how much you invest in this car, it will never be a wrx or sti.
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Old 01-31-2013, 01:49 PM   #15427
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Originally Posted by ans2k View Post

Man I have no idea what the crap the guy above me was saying. Adverse effects? There is none or just one. Money on how much the rims cost. Decrease unsprung weight decreases the rotational torque. No time to explain physics or moment of inertia. This will improve handling and acceraltion. Will this improve fuel economy? Only when accelerating but you may lose some while curising. Because there is less mass to keep the wheels in motion. Losing 60 pounds of unsprung weight has a larger effect than just losing 60 pounds off the body of the car. Going with a larger rim has a good and bad effects. Good is that you can use a skinnier tire which could have stiffer side walls for a sharper turn in. Bad is that that stiff side wall makes for a harsher ride and a lelarger rim pushes the moment of inertia father from the center of rotation which increase the rotational torque. Which could counter act the weight that you loss. If you went with 15 pound rims, you could gain some performance. Depending what tires you go with. But it is hard to give a definite answer on how much you can gain. There is no number I can give you. 7.5 inch wide is good enough for a lot of things. Your car isnt a track monster or drag beast. The only thing I can say really is that having said what I just said, get whatever makes you happy because no matter how much you invest in this car, it will never be a wrx or sti.
Did you read the article I posted a link to? It explains how unsprung weight can adversely affect the ride and handling of the suspension.
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Old 01-31-2013, 02:12 PM   #15428
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Aint nobody got time for that!
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Old 01-31-2013, 02:14 PM   #15429
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Did you read the article I posted a link to? It explains how unsprung weight can adversely affect the ride and handling of the suspension.
i have. in real world application and from first hand experience those adverse effect have very little impact to the handling of the car. road noise and ride quality are more dependable upon the selection of the tire. the article mentions that very little. the weight of the wheel may have an affect on road noise and ride quality but in the real world, these differences would not be detected. have your ever change your rim and felt like your car went to *****s because of the weight difference? I have had the opportunity to go from a 21 pounds rims (stock) to a 8 pound rims made by spoon on my s2000. and guess what, ride quality and noise went really any thing that was going through my head. the 10K price tage on the other hand was.
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Old 01-31-2013, 02:15 PM   #15430
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Aint nobody got time for that!
LOL HAHAHA sorry, so many people have been using that recently.
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Old 01-31-2013, 03:03 PM   #15431
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i have. in real world application and from first hand experience those adverse effect have very little impact to the handling of the car. road noise and ride quality are more dependable upon the selection of the tire. the article mentions that very little. the weight of the wheel may have an affect on road noise and ride quality but in the real world, these differences would not be detected. have your ever change your rim and felt like your car went to *****s because of the weight difference? I have had the opportunity to go from a 21 pounds rims (stock) to a 8 pound rims made by spoon on my s2000. and guess what, ride quality and noise went really any thing that was going through my head. the 10K price tage on the other hand was.
And was the $10k price worth whatever you gained in performance? Even so, an s2000 is a lot different than a non-sti impreza and that's the point I was making. There's not a big benefit from spending money on new rims strictly for performance. That money can be better spent on suspension parts to get the same, if not better result!
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Old 01-31-2013, 03:22 PM   #15432
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While we're on the subject of rims and tires, I wanted to ask you guys a question. I was thinking of going with a 215/50 tire instead of a 205/50 for my stock 17in rims when it comes time to replace the Yokos. The biggest reason is because I've found most 215/50 tires are a little cheaper than their 205/50 counterparts. Also, I was thinking that a slightly wider tire may increase handling by a little and the larger diameter may provide a slightly softer ride.

Do you guys think this would be ok to do? I checked a tire calculator site and the overall diameter difference is only like 1%. Also would a 215/50 tire be ok on the stock 7in wide rims? Thanks.

Last edited by jr0bb5; 01-31-2013 at 03:44 PM.
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Old 01-31-2013, 03:30 PM   #15433
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I think its a good idea. I plan on doing this as well. I doubt youll notice anything different.
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Old 01-31-2013, 03:52 PM   #15434
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I think its a good idea. I plan on doing this as well. I doubt youll notice anything different.
Thanks for the reply! I think I'm gonna go with the BFGoodrich g-Force Sport COMP-2's in 215/50. The ratings and specs sound really good for the price. I'll end up buying a dedicated set of 15" winter rims and tires for next year.
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Old 01-31-2013, 04:06 PM   #15435
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Well i am by no means an expert on wheels/tires but i have done research on the subject recently and found out a 7" wide wheel could hold a 225 tire if need be, maybe larger but not a good idea.
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Old 01-31-2013, 07:01 PM   #15436
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And was the $10k price worth whatever you gained in performance? Even so, an s2000 is a lot different than a non-sti impreza and that's the point I was making. There's not a big benefit from spending money on new rims strictly for performance. That money can be better spent on suspension parts to get the same, if not better result!
I assume you didnt read my post all the way. I wrote that. Lol. I mentioned this car isnt a wrx or sti and told the person to get whatever he liked. Also I should have i said tried the rims not bought them. For the perfomance gain 10k could have been spent better somewhere else. Lol. But honestly. Suspension will not give you the same results as lighter weight rims.

Last edited by ans2k; 01-31-2013 at 07:10 PM.
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Old 01-31-2013, 07:05 PM   #15437
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Originally Posted by jr0bb5 View Post
While we're on the subject of rims and tires, I wanted to ask you guys a question. I was thinking of going with a 215/50 tire instead of a 205/50 for my stock 17in rims when it comes time to replace the Yokos. The biggest reason is because I've found most 215/50 tires are a little cheaper than their 205/50 counterparts. Also, I was thinking that a slightly wider tire may increase handling by a little and the larger diameter may provide a slightly softer ride.

Do you guys think this would be ok to do? I checked a tire calculator site and the overall diameter difference is only like 1%. Also would a 215/50 tire be ok on the stock 7in wide rims? Thanks.
215 will be fine. Hell 225 will fit with a buldge. It will increase grip. Brake in and turns. But it will fill mushier and decrease sharp turn in.
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Old 01-31-2013, 08:44 PM   #15438
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215 will be fine. Hell 225 will fit with a buldge. It will increase grip. Brake in and turns. But it will fill mushier and decrease sharp turn in.
Wouldn't 225's be too tall unless you decrease sidewall??
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Old 01-31-2013, 08:53 PM   #15439
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Wouldn't 225's be too tall unless you decrease sidewall??
I mean what is "too tall"? Yes 225/50 would be 1.6 inch taller or .8 inch more in ground clearance. And 225/45 would be shorter than the oem spec. If you think about it. The stock 15-16-17 inch tires dont habe the same diameter.
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Old 01-31-2013, 09:04 PM   #15440
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I mean what is "too tall"? Yes 225/50 would be 1.6 inch taller or .8 inch more in ground clearance. And 225/45 would be shorter than the oem spec. If you think about it. The stock 15-16-17 inch tires dont habe the same diameter.
It will not be .8 inch increased ground clearance that much I can guarantee! Too tall is when it starts rubbing on fenders or other parts during tight turning and/or suspension travel.
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Old 01-31-2013, 09:29 PM   #15441
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It will not be .8 inch increased ground clearance that much I can guarantee! Too tall is when it starts rubbing on fenders or other parts during tight turning and/or suspension travel.
i dont see how it would not be .8 inch of ground clearance. for example, the continental dws tires. the 205/50/17 is 25.1 inches in total diameter and the 225/50/........just realized i have been looking at the crosstrek tires. lol yep you are right. about the .8 inch ground clearance being wrong. lol anywho. 225/55 /17 would be 26.7 inches tall. that would give you .8 ground clearance.

but by your definition 225/50/17 would not be too tall then. there is a earlier generation impreza that had a crosstrek wheel and tire combo and it fit. that is 225/55/17. just saying. although with a sport and mud guards/flaps i can see 225/55/17 being too tall, 225/50 would not. but 225 would be a slight bulge on the rim. it would work.
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Old 01-31-2013, 09:34 PM   #15442
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i dont see how it would not be .8 inch of ground clearance. for example, the continental dws tires. the 205/50/17 is 25.1 inches in total diameter and the 225/50/........just realized i have been looking at the crosstrek tires. lol yep you are right. about the .8 inch ground clearance being wrong. lol anywho. 225/55 /17 would be 26.7 inches tall. that would give you .8 ground clearance.

but by your definition 225/50/17 would not be too tall then. there is a earlier generation impreza that had a crosstrek wheel and tire combo and it fit. that is 225/55/17. just saying. although with a sport and mud guards/flaps i can see 225/55/17 being too tall, 225/50 would not. but 225 would be a slight bulge on the rim. it would work.
Ok just because the tire, un-inflated without the weight of the car sitting on it is 1.6 inches larger in diameter, it is NOT going to give .8 inches of ground clearance! It will make the tire .8 inches taller on each side, but it definitely will not raise the body/chassis of the car by .8 inches!
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Old 01-31-2013, 10:10 PM   #15443
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Ok just because the tire, un-inflated without the weight of the car sitting on it is 1.6 inches larger in diameter, it is NOT going to give .8 inches of ground clearance! It will make the tire .8 inches taller on each side, but it definitely will not raise the body/chassis of the car by .8 inches!
lol ok you are right. but close enough. well wait. assuming if the elasticity is constant for both tires as in if two tires are kept at the same air psi and has the same compression length say .1 inch. which will mean that is the tire has a total diameter x then with the pressure of the car, the tires will be compressed to x - .1. then the 225/55/17 would be taller by .8 inches. because there will be a constant .8 difference in the radius between the two tires. just a theory. im not going to buy another tire to prove it. lol just food for thought. the difference in tires will be constant and both tires with have the same compression from the car. but there are alot of factors in this as well. tire compound, side wall stiffness, etc.
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Old 01-31-2013, 10:47 PM   #15444
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For anyone interested, there's a cheap sway bar on eBay which I believe, but am not sure, fits our car

**EDIT: LINK WAS THE STOCK SWAY BAR**
If someone knows it fits please tell me, as I may buy it

Last edited by danstheman7; 02-01-2013 at 12:15 AM. Reason: product listed was OEM stock, my mistake
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Old 01-31-2013, 11:09 PM   #15445
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Man I have no idea what the crap the guy above me was saying. Adverse effects? There is none or just one. Money on how much the rims cost. Decrease unsprung weight decreases the rotational torque. No time to explain physics or moment of inertia. This will improve handling and acceraltion. Will this improve fuel economy? Only when accelerating but you may lose some while curising. Because there is less mass to keep the wheels in motion. Losing 60 pounds of unsprung weight has a larger effect than just losing 60 pounds off the body of the car. Going with a larger rim has a good and bad effects. Good is that you can use a skinnier tire which could have stiffer side walls for a sharper turn in. Bad is that that stiff side wall makes for a harsher ride and a lelarger rim pushes the moment of inertia father from the center of rotation which increase the rotational torque. Which could counter act the weight that you loss. If you went with 15 pound rims, you could gain some performance. Depending what tires you go with. But it is hard to give a definite answer on how much you can gain. There is no number I can give you. 7.5 inch wide is good enough for a lot of things. Your car isnt a track monster or drag beast. The only thing I can say really is that having said what I just said, get whatever makes you happy because no matter how much you invest in this car, it will never be a wrx or sti.
Haha I assure you I don't expect it to be a wrx or sti. That doesn't mean I'm not going to try to squeeze every last little bit out of it. How much more acceleration would be gained with lighter wheels? Anything actually noticeable? I know rotating mass has a huge effect on bikes but cars and completely different beasts.
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Old 01-31-2013, 11:56 PM   #15446
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Haha I assure you I don't expect it to be a wrx or sti. That doesn't mean I'm not going to try to squeeze every last little bit out of it. How much more acceleration would be gained with lighter wheels? Anything actually noticeable? I know rotating mass has a huge effect on bikes but cars and completely different beasts.
well bikes are beast compared to cars really. small motor, weight is every thing. you can do whatever you want. it is your money, spend it, burn it, wipe your butt. i am just sharing my knowledge and experience. like i said, i cant just spit numbers at you, well i can but they wont mean anything.

for $hits and giggles, lets assume the rim is a cylinder with open ends. it is not, because of the spokes, but lets assume anyways for simplicity. with the concentration of mass towards the end of the ring. the kinetic energy or the rotation of inertia of a rotating cylinder is I=MR^2. mass times distance squared. and say 2.2 pounds is 1kilogram. distance is in meters 1 in = 0.0254 m. so stock 17 alloy non sport rim looks to be 23 pounds or so. so that would be 10.45*.43^2= 1.9. now lets consider a 15 pound 17 in rims. 6.82*.43^2=1.26. so per rim you would have to use 0.64 less energy to accelerate the rim. with four rims that is 2.56 less kinetic energy to accelerate. the engine can only produce so much power. less power will be used to rotate the rim and more will be used for the propulsion of the car. does that give you your answer? no? it is clearly 2.56 less kinetic energy. what is that in terms of acceleration? NOTHING!!!

ok well it is something but nothing a 0-60 will tell you. 0-100 maybe a slight difference. it is all about corner exit speed. you will feel more of it exiting at a corner than actually mashing your foot down at a stop light. have you heard of the term "butt dyno". you will feel it in the seat of your pants but not a big numerical value like .5 second faster.

by the way this is a very very very basic level physics. i have no clue how to explain or what the super in-depth knowledge of this is. just the basic level of college and highschool physics. if i am wrong so be it, i dont care. the point was to show less energy.

Last edited by ans2k; 02-01-2013 at 12:03 AM.
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Old 02-01-2013, 12:08 AM   #15447
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For anyone interested, there's a cheap sway bar on eBay which I believe, but am not sure, fits our car

http://www.ebay.com/itm/2012-OEM-Sub...059141&vxp=mtr

If someone knows it fits please tell me, as I may buy it
dont buy it......... *sigh* that is the stock bar. there is a 100% that will fit. it is just some guy trying to sell it after he upgraded his rearsway bar. just spend 50$ more and get a 100% better bar.
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Old 02-01-2013, 12:14 AM   #15448
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dont buy it......... *sigh* that is the stock bar. there is a 100% that will fit. it is just some guy trying to sell it after he upgraded his rearsway bar. just spend 50$ more and get a 100% better bar.
Ohhhhhh, got it! Do you know the model number for the one you suggest? Or the name of it so I don't make the mistake of picking a stock one again

(and i'll remove the old link so people don't make my mistake)
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Old 02-01-2013, 12:29 AM   #15449
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the stock bar is 16mm get a 19mm. http://www.subarugenuineparts.com/pr...oducts_id=1690
http://www.ebay.com/itm/2008-SUBARU-...d8fdea&vxp=mtr

if you are going to buy one. for 10 dollars!!!!!! buy new!!!!
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Old 02-01-2013, 08:43 AM   #15450
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20% off at subarupartswarehouse with SOA13
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