What's the difference in the real world?

How much of a difference is there between an 11 lb 15x7 wheel with 195/55 15 tires and a 17 lb 16x7 wheel with 205/45 16 tires? Handling and acceleration/braking/responsiveness, ride, etc.?

Thanks.

btw - I know the theories of lighter, wider wheels and lower profile tires, but I don't know how much of an actual difference say 6 lbs and a little lower profile tire would make in the real world when put on a 160 (flywheel) Civic Si. I also plan on doing F.I. (ie JRS).

I went from a 17lb 16x7" Konig Burners with 215/40x16" Kumho 712s to a 14lb 16x7.5" Kosei K1 with 215/40x16" Kumho 712s and the difference was noticeable. Car accelerated quicker and suspenion was able to work quicker due to the lighter weight. I'm now using a 13lb Kosei K1 and response is even better.

I just took off my 15s with 195/55s and put on my steelies, and I could tell a difference with that. I mean it is only a marginal change in size, width and weight but the difference is apparent (at least to me).

I think you'll definitely feel a difference between a 17lb 16 and 11lb 15. Not only in the weight, but with the added comfort a thicker sidewall will provide.

As my friend Josh says.... "rolling resistance is everything". But in a real-world scenario, it's a give and take proposition. You gain some better response on take-off via the lower profile (and more if you go from steel to aluminum) and also better handling, but you lose some of the confort of the thicker sidewall as stated earlier.

Also, the low-pro tire/wheel combo will help in day-to-driving from my experience. Just run a few tests and swaps and see if the diff comes through. Less flex from a sidewall and a wider (perhaps better?) tread will increase overall stopping and handling. Not by much on paper, but an extra foot comes in handy on the road.

Hope this helps.:bloated:

I just want to say thanks guys for your responses. That helps. I'll probably go with the 15's. They're the Axis mag-lite's 15x7. Was thinking of pairing them with 205/50 15 Kuhmo 712's. Any opinions on the wheel/tire/brands/size/etc?

Thanks again,
M
:flash:

Well what are you going ot use the setup for? Autocross? Daily driver? Road racing?

Daily driver. I want to make it perform as good as it can with what I do to it though. I don't mind occaisionally lining up at stoplights (and I want the best chance at winning -- who wants to lose?), but I don't have plans right now to take it to the track. I am also a perfectionist. I want my car to be just right for me in many respects (performance, looks, ride, responsiveness, braking, etc. ...who doesn't?)

~M

:smoka:

The best affordable tire is the Falken Azenis. For $60-70 a tire you get almost the same performance as some DOT racing tires. I'm running 205/50x15" Azenis with Kosei K1s (15x7") which weigh about 13-14lbs. Those cost about $125-150 each.

And please don't street race, it's dumb, stupid, and just plain immature.

Thanks, I appreciate all your advice. You seem very knowledgable (please excuse any of my spelling errors).

~M

;)

Originally posted by MattyO217
Thanks, I appreciate all your advice. You seem very knowledgable (please excuse any of my spelling errors).

~M

;)

I'm just trying to be helpful. And to think 6 years ago I didn't even know how to change my oil :)

I'm now using a 13lb Kosei K1 and response is even better.

Going from a 40 series (you said you had 215/40 16's) tire to a 50 series tire (205/50 15's) did you notice any DECREASED responsiveness? I know you said response is better, but was that just due to the lighter weight (i.e. made acceleration, braking, and maybe grip better)? I guess what I'm thinking is wouldn't you lose some turn-in responsiveness (like maybe a little mushier when abruptly turning due to the slightly thicker (50 series) sidewall)? Maybe I'm wrong. Does it matter if it's say, a 50 (i.e. 205/50 15) series Z rated tire vs. a 45 series Z rated tire(i.e. 205/45 16)? I guess I just want to make sure I'm making the right choice for my taste in performance. I want my car to be responsive as possible. I'm probably nit picking but just want to be sure.

Thanks for you help,
~M
:eek:

Originally posted by MattyO217


Going from a 40 series (you said you had 215/40 16's) tire to a 50 series tire (205/50 15's) did you notice any DECREASED responsiveness? I know you said response is better, but was that just due to the lighter weight (i.e. made acceleration, braking, and maybe grip better)? I guess what I'm thinking is wouldn't you lose some turn-in responsiveness (like maybe a little mushier when abruptly turning due to the slightly thicker (50 series) sidewall)? Maybe I'm wrong. Does it matter if it's say, a 50 (i.e. 205/50 15) series Z rated tire vs. a 45 series Z rated tire(i.e. 205/45 16)? I guess I just want to make sure I'm making the right choice for my taste in performance. I want my car to be responsive as possible. I'm probably nit picking but just want to be sure.

Thanks for you help,
~M
:eek:

Well the biggest thing was the tires. The Azenis in 215/40x16" weighed about 40lbs on 16x7.5" wheels. PLus those tires rubbed like crazy! They were more like 225/40x16" or even 235/40x16". The 205/50x15" on 15x7" Kosei K1s weighed 32lbs. But those are more like 215/50x15" or close to 225/50x15" Very wide tires.

But yeah braking, accelerating, and turning improved going from the 16s to the 15s and turn in didn't really change either. PLus there are more "high performance" tires in 15s than 16s.

I also feel safer driving on the streets with 15s than 16s. Having a larger sidewall helps cushion the ride, and protect from potholes better.

I just got done talking to a guy at Wheelmax. He said to go with 17's if I plan on modding my car to 200-300 hp. I am still unsure about what size wheels to go with! :confused: I don't trust salesmen too much. I'd think there'd still be a substantial (spelling?) performance gain even with a turbo/supercharger set up (on a 1999 Si) with light weight 15's (11.5 lbs) vs heavier 17's (18-22.5 lbs depending on which 17 I'd go with). I'd imagine that breaking distance would be increased with the 17's, along with slower ET's, harsher ride quality, but better responsiveness (turn in, salom, etc.), and possibly better grip (ie would do better on skidpad test) due to the stiffer sidewalls' higher resistance to rolling over (am I right?). But I read a SCC book that did a test between different sized wheels and tires. The 205/40 17's had a shorter stopping distance than 205/50 15's (by about a whole one foot! heheh. but none the less...it's still a heavier wheel). The tires I'd get (Kuhmo 712 or Sumitomo HTRZ II) would be 205/50 15 V (possibly W) verses 205/40 17 W or Z speed rating. I like the looks of the 17's, the 15's aren't bad, but I don't want to give up much performance. How much performance would I lose by going with the 17's and what other advantages would I gain besides appearance (i.e. responsiveness, grip in cornering, etc?). Also what about the heavier wheels and the drive shafts, etc? How much hp can the stock parts handle?

Thanks for all the help,
~M
:)

Originally posted by MattyO217
I just got done talking to a guy at Wheelmax. He said to go with 17's if I plan on modding my car to 200-300 hp. I am still unsure about what size wheels to go with! :confused: I don't trust salesmen too much. I'd think there'd still be a substantial (spelling?) performance gain even with a turbo/supercharger set up (on a 1999 Si) with light weight 15's (11.5 lbs) vs heavier 17's (18-22.5 lbs depending on which 17 I'd go with). I'd imagine that breaking distance would be increased with the 17's, along with slower ET's, harsher ride quality, but better responsiveness (turn in, salom, etc.), and possibly better grip (ie would do better on skidpad test) due to the stiffer sidewalls' higher resistance to rolling over (am I right?). But I read a SCC book that did a test between different sized wheels and tires. The 205/40 17's had a shorter stopping distance than 205/50 15's (by about a whole one foot! heheh. but none the less...it's still a heavier wheel). The tires I'd get (Kuhmo 712 or Sumitomo HTRZ II) would be 205/50 15 V (possibly W) verses 205/40 17 W or Z speed rating. I like the looks of the 17's, the 15's aren't bad, but I don't want to give up much performance. How much performance would I lose by going with the 17's and what other advantages would I gain besides appearance (i.e. responsiveness, grip in cornering, etc?). Also what about the heavier wheels and the drive shafts, etc? How much hp can the stock parts handle?

Thanks for all the help,
~M
:)

The worse people to ask what size to get are places that sell them. Of course he wants you to get 17s. 17s are more expensive, more prone to pothole damages, and tires cost more.

I'd say stick with a 15-16" wheel if you are going to get a package. But on the other note modding your car to 200-300hp is a bit expensive. I think you should first prioritize. Not know what you are doing in the first place and you could waste $$$ like I did :)

Thanks for your responses.:alien:

My next question is somewhat technical. What would give better traction: 205/50 15 11.5 lb wheel or a 205/40-17 17 lb wheel? It's technical because I'm compairing the decreased weight to the increased contact patch. I don't know if this can be accurately answered. I would think that how much horsepower I plan on making would come into play here. I say that because as you increase hp, traction becomes a bigger issue and I'd think that in straight line acceleration, the increased contact patch would be better. But as for cornering, what would give more grip, all things equal except for wheel weight and tire size? A wheel that's 5.5 lbs lighter with a slightly smaller contact patch or a wheel that's 5.5 lbs heavier with a slightly larger contact patch due to a lower aspect ratio??

Thanks for the help,
M
:smoka:

Originally posted by MattyO217
Thanks for your responses.:alien:

My next question is somewhat technical. What would give better traction: 205/50 15 11.5 lb wheel or a 205/40-17 17 lb wheel? It's technical because I'm compairing the decreased weight to the increased contact patch. I don't know if this can be accurately answered. I would think that how much horsepower I plan on making would come into play here. I say that because as you increase hp, traction becomes a bigger issue and I'd think that in straight line acceleration, the increased contact patch would be better. But as for cornering, what would give more grip, all things equal except for wheel weight and tire size? A wheel that's 5.5 lbs lighter with a slightly smaller contact patch or a wheel that's 5.5 lbs heavier with a slightly larger contact patch due to a lower aspect ratio??

Thanks for the help,
M
:smoka:

If you have a 205/50x15" tire and a 205/40x17" tire they are both the same width. So you have the same contact patch. But the 15" wheel is 6lbs lighter and that doesn't take into fact the tire weight difference. Since the tire has a smaller sidewall you need more steel belts (reinforcement) to keep the sidewalls stiffer hence making the tire heavier too.

My 17" wheel and tire package weighed in around 45lbs. My 15" is 32lbs. That's a difference of 13lbs per corner or total of 52lbs your car has to carry.

Plus you would get better response from the 205/50x15" compared to the 205/40x17" cause the 205/50x15" is 1" shorter for better gearing. You would accelerate quicker off the line. The 205/40x17" also will mess up your speedo and odoemeter by about 1-3%.

If you have a 205/50x15" tire and a 205/40x17" tire they are both the same width. So you have the same contact patch.


Not entirely true. It is true that both tires measure the same width but this width is NOT the contact patch. The 205 is a measurement of the width of the tire in respect to the sidewall. In other words tire width is from sidewall to sidewall. A tire's sidewall is not perfectly square, it is somewhat rounded, so not all of a tire's width is put on the ground. But as the aspect ratio decreases the sidewall becomes more square, thus putting more of the measured width on the ground. If you compare a 70 series tire to a 40 series tire, this is very apparent. So a lower profile tire increases contact patch area, but not the measured width of the tire (205 mm).

Peace out,
MattyO217

:alien: