LAST EDITED ON 04-Dec-00 AT 07:54 AM (PST)

185/70/14s no less. These are going to last 2wks at the current rate I'm lighting em up. I mean I'm lighting em up all the way through 8 lane intersections (for no other reason than its so effortless). Now I can finally feel my mods. I didn't have monster wheels to begin with (17" @23lbs each). Hell I damn near tempted to keep it this way.. FOREVER (nah).



Stan2gnt
95 Talon ES-I-NOS
http://members.nbci.com/FlyEsi/home.htm
You too can have a never updated site complete with old info and dated pics!

Do you think you would see a difference at the track with those tires over your 17's. I am thinking about trading my stock 16" GS wheels for a set of the RS rims and tires. I run 17's as well, but am thinking about running the 14's at the track next summer. Since I started modding my car (performance wise), I have had those 17's on my car. You think I would notice a big difference putting those 14's on?

I think a lot of people run the smaller rims at the track for faster times. I would bet you would see a difference in your times.
I would like to see what the difference is. Anybody go to the track and run a couple with 17" and then swap for the 14". What was the difference???

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

I know Todd VX100 (or something like that) has run with 14" and 16" tires. He said he was having trouble breaking back into the 15s (from low 16s) until he put the stock 14s back on. I'm pretty sure you'll be able to launch better with the 14s if nothing else. When it gets warm again the first thing I'm doing is getting a set of 14" drag radials or slicks. If I could turn that wheel spin into foward motion who knows what it would do.



Stan2gnt
Stan2va@aol.com
Stan2gnt@yahoo.com
95 Talon ES-I-NOS
http://members.nbci.com/FlyEsi/home.htm
You too can have a never updated site complete with old info and dated pics!

You're right Stan. I had run a fastest time of about 16.1 with 16 by 8 inch rims, mazda RX-7 rims to be exact, which are very light, and 225/50 tires which also wern't all that heavy. When I put the stock rims/tires back on I hit 15.8. It was a bit colder that night too, so I'd think the difference was at least 2/10ths of a second.

I noticed the power difference as soon as I put on the stock tires again,the car felt noticeably faster, and going to the drag strip proved it.

If you're going to drag race, stick with the stock RS rims and tires, I would say you can't beat them.

I'm still keeping the other setup for autocross, the handling is great with those rims and tires!

Todd Scungio
98 RS
15.803 @ 86.48 MPH

stan do you know the weight of the stock 14's or the stock alloys? im curious about my wheels hindering my performance. my 19's weigh 25.3 lbs according to konig, and thats chrome. i dont know how they pulled off only 25 lbs on a chrome 19". i dont know what my 18s weighed but i couldnt tell a difference. then again i was on stock alloys, not steeleys. someone post the weights if they know them please, it would be helpful

I dont know the weight of either but I do know larger diameter tires also weigh more than smaller tires and thats often overlooked. So even if your 19's weighed 25lbs. The tires will likely be heavier than anything smaller. I can see how they pulled off 25lb 19's. Thats as easy as the process used to make them. What I don't know is how they pulled it off so cheaply (they aren't very expensive for there size, weight and looks).




Stan2gnt
Stan2va@aol.com
Stan2gnt@yahoo.com
95 Talon ES-I-NOS
http://members.nbci.com/FlyEsi/home.htm
You too can have a never updated site complete with old info and dated pics!

yeah that was why i was wondering how they did it because the tantrum is a one piece wheel, not designed to be lightweight. but i dont understand how a smaller higher profile tire with more rubber would weigh more than a 225/35/19 with only an inch and a half of sidewall...one of lifes little mysteries i guess.

Even if the wheels weighed the same. the 14" wheel would spin more easily than a 17" or 18". The distibution of mass is different. Because in the 14" wheel the weigh actually has a shorter path to complete around the axis of rotation. It's like an ice skater they spin the fastest when their arms and legs are tight against their body and and to slow themselves down they put their arms and leg out. So for a rotating mass the smaller the better. Hell find 13" rim for the track, and you'll have another gain.
Sorry if this explanation didn't make sense I haven't had to do physics in a couple years now. If something doesn't make sense let me know I'll try to elaborate

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

>Even if the wheels weighed the
>same. the 14" wheel would
>spin more easily than a
>17" or 18". The distibution
>of mass is different. Because
>in the 14" wheel the
>weigh actually has a shorter
>path to complete around the
>axis of rotation. It's like
>an ice skater they spin
>the fastest when their arms
>and legs are tight against
>their body and and to
>slow themselves down they put
>their arms and leg out.
>So for a rotating mass
>the smaller the better. Hell
>find 13" rim for the
>track, and you'll have another
>gain.
>Sorry if this explanation didn't make
>sense I haven't had to
>do physics in a couple
>years now. If something doesn't
>make sense let me know
>I'll try to elaborate

You got it right Mike, that's a good explanation.

Going along those same lines, the mass at the VERY OUTER EDGE of the tire is what should affect the rotational inertia the most. The tire's tread is further out than the rim of the wheel, right? So the tire should affect the rotational inertia more than the rim. The larger rim should also have an affect, but I'm guessing the wider tire is causing most of the "power loss."

My tires were 225s, compared to 195s that's 15% more tread (and at least 15% more weight) at the very outer diameter of the tire, now multiply that by 4 tires and I guess it was enough to cost me that 2/10ths at the drag strip.

So, a heavier rim might not make all that much of a difference, a heavier/wider tire would. Of course lighter is always better, since you also have to accelerate that mass in a straight line, and it adds to suspension unsprung weight.

So as crazy as it sounds you might see a small negative difference with a 195 tire on a 18 inch rim (bear with me here, I know no one would do this) and a huge negative difference with a 225 tire on a 14 inch rim (if the outer diameter is the same)

Todd Scungio
98 RS
15.803 @ 86.48 MPH

With regards to your extra wieght of the tire very good point also, I wasnt really concidering the tire weight. Does any one know the differences in weight of stock tires vs. 225s?

I think the differences in tire weight are going to be much less than that of wheel weight, rubber has a lighter weigh pet volume than metal. Given a wheel weights 25lbs say I can't imagine that a tire weighs more than say 10lbs at most. If I'm wrong on this someone please correct me. In which case the tire will have more of an effect than I thought. And I think you only need to multiply the extra weight by 2 since its a FWD car and not an AWD car. We can concentrate on the wheels that the engine is directly turning. I think we can look at the extra friction and drag the rear tires create by being wider. This is the reason drag racing cars have bicycle tires up front. But I think you're right we need to look at the outer edge weight.

Let's concider the weight distribution:
Assuming same width tires say 225s one on 14" wheels one on 18: wheels. on the 14" the concentration of mass is closer to the center allowing the wheel to spin more easily. On the 18" wheels the tire and weigh of the rim are concetrated around the outer edge of the rotation mass. Which should make it harder to turn. I still think that the rim has a larger effect, based on what I think the weigh of the wheels vs. the tires is. If someone knows the weights of the tires alone I may change my thoery.

Also the smaller rim with larger tires is going to has it's mass closer to the center wich would in part offset the larger rotating mass of the wider tire. If this is done on a 18" rim you are only adding to the outer mass, or at the very least not taking much away from it. Let me know what you think.

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

Well, the potenza RE92 stock tires which are 195/70R14s weigh 20 lbs each, the Pilot SX-GT 225/50R16s I have are 22.2 lbs each. You're right, the tire weight isn't usually as great of a differnece as the weights of the rims. The RX-7 rims I have weigh 13.8 lbs each, the stock alloys are approxomately that same weight (I don't know for sure), so the 225/50s on RX-7 rims weigh only about 2 lbs more each for rim and tire.

But you have to remember WHERE that weight is! With a 225 tire more of that weight is in the steel belts since it's wider, and that's at the very outer edge of the tire. That's why the weight may not be very different, but it's rotational inertia will still be much greater. So it is the LOCATION, or DISTRIBUTION of that mass which made the difference, not the actual mass itself.

You're right Mike, a 14 inch rim will be better than an 18 inch rim if the outer tire diameter is the same, but the MAJOR effect on the rotational inertia will be the tire, not the rim, because that weight at the very outer diameter of the tire will have the greatest effect on the rotational inertia.

Also, just because our cars are 2wd doesn't mean the the rear tires can be wide on heavy rims. You see all the honda guys at the drag strip put their stock tires on the front but keep the heavy rims/wide tires on the back. I love racing those guys :) they are typical rice boys who don't know what they are doing. Those heavy wheels may not have power going to them, but you STILL have to turn them! If they are on the front or the back, it should still have the same effect on the car, it would slow it down, which is EXACTLY why the top fuel dragsters have bicycle tires on the front, because it DOES make a difference.

And besides just turning them, the mass has to be accelerated in a straight line as well (as if you're adding 20 lbs worth of weights in your car's trunk), so it makes no sense to keep them there.

Todd Scungio
98 RS
15.803 @ 86.48 MPH

I see your point on the rear tires. I'm not sure it makes as much of a difference as the front wheel weigh, but it definately should be concidered, if for no other reason as for extra weight.
Since the tires weigh more than I thought and most of that weigh will be concetrated on the out edge of the tire. They would have more of an effect than I thought. Which makes going to a larger diameter wheel even worse you put even more weigh on the outside of the axis of rotation. The difference in the weight between the tires isn't as great but the whole tire weighs more than I thought so it has a bigger influence. Plus with the thinner sidewall, the weight really is at the very edge.
I'd like to see a test done compairing same size rims and wider tires to see what effect this would have. I'd love to play with this at the track... too bad I don't have the money to go and buy a bunch of rims and tires and test the theory. Well we'll just have to settle for discussing it.

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

I just picked up the Jan 2001 issue of Sport Compact Car. There is an article about this exact thing. I haven't had a chance to sit down and read the artle yet but I thought you guys would be interested.

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

Here is a quote from the article, it is from the "AEM Ford Focus Dealer Package" article, written by Dave Coleman, found at http://www.sportcompactcarweb.com/


"The 16-inch Enkei wheels were a source of confusion at the drag strip. Paired with 205/45-16 Toyo T1-S tires, they weighed only 2 lbs more than the stock wheels and tires, but somehow, putting them on added 0.3 seconds to the Focus' already long quarter-mile time. Eight lbs isn't enough to account for that difference, and even if rotational inertia was considered, the total weight was less than 20 lbs. Coastdown tests on the dyno showed the Toyos didn't have any more rolling resistance than the stock tires either, so we really don't know what to attribute the difference to. The Focus is full of mysteries."


This is weird in that it was the EXACT same thing that hapened to my car! 2 lbs more per wheel, but 3/10ths slower 1/4 mile times!

Why are they so confused? They don't have a clue! 8 lbs. at the VERY OUTER DIAMETER of the tire IS enough to cause a significant difference in rotational inertia, especially in a car with even less HP than our cars, they simply don't know what they are talking about (no suprise there). The tires may not have more rolling resistance, but that doesn't mean anything if the rotational inertia is higher.

Todd Scungio
98 RS
15.803 @ 86.48 MPH

Yes it enough. And you're right they have no clue. I pay more attention to the facts, than their interpretation of them. How many of them have had a physics class : ) which is about all I've actually red of the artle were the time slips and a brief skimming to see what they did.
Hell why don't you and me write an article... ha ha

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

BTW if approximately a 5% increase in weigh isn't significant to them... what is?

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

LAST EDITED ON 06-Dec-00 AT 01:05 PM (PST)

Hey Michael...

Isn't 8 pounds of 2564lbs. actually 0.3% ?

Don't pound on me for this one Saturday man! ;-)

Unless of course, if you were only referring to the total weight of the wheels only! heheh :7


Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)


http://springfielddsm.homestead.com/JasonsPics.html

Jason

yeah bud I was just talking about the wheels. I was being conservative and didn't add any weight for the a bigger wheel just the tires mass.

I'll let this one slide without a beating :P

BTW Saturday is suppose to be above freezing and no snow or rain. Hopefully the forcast stays that way.

"To strive to seek to find... and not to yield."
Michael J. Kulaga
Michael_97RS@2gntDSM.zzn.com
aol IM: MJKulga

don't know about tire and wheel weight seprately but when i weighed my stock 14'sw/tires they were20lbs even. you figure in a 8-12 pound tire and yu got a wheel that weighs 8-12 lbs.my 16's with 205/45/16 nitto drags way 28lbs. i can really tell a huge difference when i put the 14's back on. i get a lot more wheel spin with the 14's but i also get faster acceleration. just my .02. 420a rules!!!!!!!

Actually, Dave Coleman is an Engineer. I'm sure he has had a few physics classes in his day.

14" rule in the snow .. my rs hasnt gotten stuck once !! i might have huge tires and a wheel well that could hide an elephant ..but thats ok i dont get stuck

14" rule in the snow .. my rs hasnt gotten stuck once !! i might have huge tires and a wheel well that could hide an elephant ..but thats ok i dont get stuck