View Full Version : Scary Math


Cooper47
06-14-2007, 03:26 PM
So I'm contemplating new tires among other things and just doing some basic math.......

4 Kumho 710's = $1088 ($272 x 4)
Shipping = $60
Installation = $100
Total = $1248

Okay, so I can deal with that until I start thinking about the flip side.......Rumor has it these tires are no good after roughly 60 runs even if they still have rubber....They just start going away.

So if you take $1248 and divide it by 60 you get $20.80 per run.....:Eyecrazy: Top that off with a local entry fee of $35 for usually a course that is in the 40-50 second range and you're now looking at s are now $32.46 per run or roughly .65 cents per second.

Am I the only one wondering if being competitive in this sport has gotten a little out of line with minimizing costs and maximizing competition?

And yes, I know I'm a cheap a$$......

mwood
06-14-2007, 03:35 PM
Speed costs money...how fast do you want to go?

Seriously, even with the Kumhos being good for 90-100 runs, which they are, they aren't exactly cheap...anymore. It is what it is....:)

idriverx8
06-14-2007, 03:37 PM
I think the V710 has excellent grip up to 120 runs.
They are deffinately off the pace of a new tire after 25-30 runs, but on an RX-8 I think at 60 runs they may be .25-.50 seconds slower than new.
I am probably on my 10th set of V710's.

Cooper47
06-14-2007, 03:40 PM
I think the V710 has excellent grip up to 120 runs.
They are deffinately off the pace of a new tire after 25-30 runs, but on an RX-8 I think at 60 runs they may be .25-.50 seconds slower than new.
I am probably on my 10th set of V710's.

It would be interesting to see someone chart the "falloff" of the 710........Maybe we can create a PAX system for tires? :lol2:

XDEEDUBBX
06-14-2007, 04:01 PM
wow that is costly math!

Miatamoto
06-14-2007, 04:01 PM
:banghead: I'd be really happy if I could get 120 runs out of a set of V710s before they cord.

What's your average run length... 30sec, 60sec, 90 sec???

clyde
06-14-2007, 04:13 PM
roughly .65 cents per second.

Drive slower to maximize value. :spank:

mwood
06-14-2007, 04:21 PM
Drive slower to maximize value. :spank:

OK, who's going to say it? ;) :spank:


I guess it's like golf...more swings means more value for your $$

TeamRX8
06-14-2007, 04:23 PM
if you think that's scarey add in tow vehicle cost, fuel costs, hotel & food costs, etc. for the serious National level competitors

if it's a dedicated Solo2 car add in that vehicle cost including insurance etc.

ULLLOSE
06-14-2007, 04:33 PM
So I'm contemplating new tires among other things and just doing some basic math.......

4 Kumho 710's = $1088 ($272 x 4)
Shipping = $60
Installation = $100
Total = $1248

Okay, so I can deal with that until I start thinking about the flip side.......Rumor has it these tires are no good after roughly 60 runs even if they still have rubber....They just start going away.

So if you take $1248 and divide it by 60 you get $20.80 per run.....:Eyecrazy: Top that off with a local entry fee of $35 for usually a course that is in the 40-50 second range and you're now looking at s are now $32.46 per run or roughly .65 cents per second.

Am I the only one wondering if being competitive in this sport has gotten a little out of line with minimizing costs and maximizing competition?

And yes, I know I'm a cheap a$$......

I have no problem running a 60 run V710, but I do agree they are downhill from that point. The good news for you is those 60+ run tires are great for Castle, they seem to work just fine on the concrete. :yesnod: I have no doubt you can get 100+ runs total out of a set on asphalt without flipping them, most of my take-offs go to a number of local guys when I hit 100 runs and they can usually get a practice day out of them. imho at 100 runs they seem to have the same level of grip as the old V700s, .5-1 sec off the pace of a fresh V710.

You forgot to add to your list the "must have uber light wheels" and replacing the shocks you bought with a set of Koni's. :stickpoke

blipblip
06-14-2007, 04:50 PM
Its interesting that seems like everybody is talking about the same thing at the same time but at a different location. My buddy and I were talking about this. And considering how much it cost for the seat time, it almost felt like doing track driving (NASA time trial) is more economical. But then I don't know all the hidden cost of doing that as well. Can someone shed some light?

edit: Just did some general calculation. NASA TT cost about $6/min seat time including event fee and transponder rental.
One hidden cost: Messing up a corner = writing off a car / wife gets a lot of money from insurance co....

mp5
06-14-2007, 05:11 PM
The Hankooks are a little cheaper... :)

I might actually consider trying them out if I can get a discount. Need to talk to the local contract driver.

mwood
06-14-2007, 05:11 PM
Its interesting that seems like everybody is talking about the same thing at the same time but at a different location. My buddy and I were talking about this. And considering how much it cost for the seat time, it almost felt like doing track driving (NASA time trial) is more economical. But then I don't know all the hidden cost of doing that as well. Can someone shed some light?


Autocross is about as cheap as it gets.
As soon as you start doing actual track time, your costs begin to go up. First, you just have more wear items. Example: a set of brake pads will last years autocrossing, but will be toast in a weekend of lapping or other track use. You'll be replacing tires more often, but if it's just lapping days, at least you don't need the stickiest tires and can get by with a Victoracer or some other less expensive DOT R tire. Also, brake fluid, wheel bearings, wheel studs, anything adversely effected by heat (like brake caliper boots and stuff like that) etc. will be a constant cost. There's also the time or dollar cost of labor...keeping a track car ready to go requires diligence.
Next, throw in the fact that most road course oriented events are full weekends, so, you'll have all the costs of doing National level autocross (gas, loss of time at work, hotels, meals etc.) just to participate in local track days.

ULLLOSE
06-14-2007, 05:25 PM
Its interesting that seems like everybody is talking about the same thing at the same time but at a different location. My buddy and I were talking about this. And considering how much it cost for the seat time, it almost felt like doing track driving (NASA time trial) is more economical. But then I don't know all the hidden cost of doing that as well. Can someone shed some light?

edit: Just did some general calculation. NASA TT cost about $6/min seat time including event fee and transponder rental.
One hidden cost: Messing up a corner = writing off a car / wife gets a lot of money from insurance co....

Track day VS autoX $$$$.... The quick stuff I can think of: tires that can last a season of autox may be gone in a few track weekends. Brake pads and rotors that can last a few years autox can be gone in a few weekend on the track. The tires and brakes are all relative to how hard you push it. Trans and diff fluids should be changed much more often on the track, the natl level road racers I know change them every weekend. Fuel, a gallon for an autox but up to maybe a tank for a track day.

If you f-up real bad at an autox you typically eat some cones and swallow your pride, although a few times a year you hear stories about car damage due to driver error or poor course layout.

If you f-up on a road course and get lucky you just eat some dirt, if you screw up big time you take you car home in your pocket assuming you did not get hurt because most track day guys do not have the same level of safety equipment as the natl level road racers.

The worst part of the track day is the other guy..... You can be minding your or business driving well within your means and some dumb@ss car ruin your weekend. :rant:

Cooper47
06-14-2007, 05:30 PM
You forgot to add to your list the "must have uber light wheels" and replacing the shocks you bought with a set of Koni's. :stickpoke

Yes, as soon as I can find a set of wheels that are lighter then yours made of unobtanium I will pick them up.....;) Until then, they're just another excuse as to why you're faster then the rest. The shocks are still up in the air, I really like them on the street and they seem to have settled down to the OE ride height.

ULLLOSE
06-14-2007, 05:41 PM
The shocks are still up in the air, I really like them on the street and they seem to have settled down to the OE ride height.

Sounds like the words of a man trying to convince himself that he made the right choice. However you and I both know as you compare your 4X4 to Woods in grid you tear up a little. :icon_no2:

blipblip
06-14-2007, 05:44 PM
Correct me if I am wrong. I find that autocross use up more tires than track. To me, it is 'how much' the tires were used up vs 'how' the tires were used up. Seems like on track, the wear pattern is more even.

Either way, is NASA timetrial that hard on the car (as much as w2w?) I was doing about 20hours total track time last year and the maintenance on my car was about the same as when I was only doing autocross. And on those track time, I am about 2 sec off per lap on a 1min 4x sec track with street tires, comparing to showroom stock with dot r tires.

Sorry guys, don't mean to hijack the thread, and definitely don't mean to argue. I just want more information before I commit myself....

TeamRX8
06-14-2007, 05:46 PM
they settled down to the OE ride height because the OE shocks are high pressure too

low/no gas = considerable ride height drop

ULLLOSE
06-14-2007, 05:53 PM
Correct me if I am wrong. I find that autocross use up more tires than track. To me, it is 'how much' the tires were used up vs 'how' the tires were used up. Seems like on track, the wear pattern is more even.

Either way, is NASA timetrial that hard on the car (as much as w2w?) I was doing about 20hours total track time last year and the maintenance on my car was about the same as when I was only doing autocross. And on those track time, I am about 2 sec off per lap on a 1min 4x sec track with street tires, comparing to showroom stock with dot r tires.

Sorry guys, don't mean to hijack the thread, and definitely don't mean to argue. I just want more information before I commit myself....

I would like to see some lap times to back that up. What track and who's times were you looking at?

A buddy of mine is the 3 time Sopac T2 champ and has been on the front row at the runoffs the last two years. He uses a new set of pads, rotors and tires every weekend. If you want to run at the top that is what it takes. If you want to cruise around and tour the tracks you can run all year without lifting a finger. The slower you are the longer stuff last, and there are a lot more slow people than fast at a track day. imho a track day does not compare to a natl level road race. Some cars do cost less to run and do not beat up parts as quick, but if anyone can run all year on the big track with one set of tires they are driving slow.

ULLLOSE
06-14-2007, 06:07 PM
It is possible to do track days on the cheap because there is no competition, it is just about having fun and going as fast as you can and there are no rules to prep your car to. You could pick up some GrandAm cup Hoosier bricks that will last a long time, or ever run street tires, it does not matter because it is not a race so lap times don't count.

However that is not the same as racing your car..... The only way to race cheap is to lose. It does not matter if it is autox or a road race, if you want to win you will have to spend money. I don't care how you try to break it down, laps per $, autox will cost less when you look at the big picture no matter what. The nice thing is you have a choice, if hanging out in a parking lot all day for 3 minutes of track time is not your thing just dig a little deeper into your pocket and go to the big track. But don't get some silly idea that on a beer budget you are going to run lap times with the top guys.

blipblip
06-14-2007, 06:17 PM
Typo on the previous post. It is suppose to be 1min 5x sec per lap.

I was driving a Mini Cooper S 6spd w/factory LSD, no mods, with 17" lightweight wheels and Azenis RT-615. Fastest lap time 1:56.xx using a stop watch. Consistent lap time 1:57-1:58. Don't have anything to show.

A SWDIV SCCA Club SSC Mini Cooper S is doing similar lap time albeit he was doing some defensive line. I figure that probably adds 2 sec to his total lap time. Result can be found here http://www.sowdivscca.org/2006raceresults.aspx
August event Sunday group 5

Point is that I am not trying to do wheel to wheel racing. I am just wondering how much will it cost to run time trial vs serious autocrossing. Bear in mind time trial does not require you to go all out for the whole length for each session. And passing is not required (for what I've seen, most of the time you just fall back to create space).

ULLLOSE
06-14-2007, 06:38 PM
Typo on the previous post. It is suppose to be 1min 5x sec per lap.

I was driving a Mini Cooper S 6spd w/factory LSD, no mods, with 17" lightweight wheels and Azenis RT-615. Fastest lap time 1:56.xx using a stop watch. Consistent lap time 1:57-1:58. Don't have anything to show.

A SWDIV SCCA Club SSC Mini Cooper S is doing similar lap time albeit he was doing some defensive line. I figure that probably adds 2 sec to his total lap time. Result can be found here http://www.sowdivscca.org/2006raceresults.aspx
August event Sunday group 5

Point is that I am not trying to do wheel to wheel racing. I am just wondering how much will it cost to run time trial vs serious autocrossing. Bear in mind time trial does not require you to go all out for the whole length for each session. And passing is not required (for what I've seen, most of the time you just fall back to create space).

Just a heads up SCCA slows the Mini down a lot... In SSC trim the Cooper S has to weigh a porky 2875 lbs w/driver, has a 50mm intake retrictor plate and does not get to use the factory LSD. So it is hard to compare results.

Also that driver finished 12th at the runoffs last year and was about 2.6 seconds off the quick lap.

If you want to run track days cheap pick up some 17" wheels, tires are cheaper and easy to find lots of used ones in those sizes, and stay out of trouble. :)

blipblip
06-14-2007, 06:54 PM
Just a heads up SCCA slows the Mini down a lot... In SSC trim the Cooper S has to weigh a porky 2875 lbs w/driver, has a 50mm intake retrictor plate and does not get to use the factory LSD. So it is hard to compare results.

Also that driver finished 12th at the runoffs last year and was about 2.6 seconds off the quick lap.

If you want to run track days cheap pick up some 17" wheels, tires are cheaper and easy to find lots of used ones in those sizes, and stay out of trouble. :)

Thanks for the info. Now I am glad I traded the Mini for Rx-8 :)

I still like autocross a lot. Just looking at some alternatives. So...another question, other than the $1248 for tires, what other hardware is needed to make RX8 competitive in BS? (I guess a set of konis, light weight wheels?) And how much?

Cooper47
06-14-2007, 06:59 PM
I still prefer autocross to trackdays just because it's real competition with hard times, conditions, pressure, etc......Plus, pushing a car pasr 100% out on the track can come at a hefty price and is generally looked down upon. It's almost applauded in an autocross.

Still, 18's are expensive!!! :eek:

ULLLOSE
06-14-2007, 07:16 PM
Thanks for the info. Now I am glad I traded the Mini for Rx-8 :)

I still like autocross a lot. Just looking at some alternatives. So...another question, other than the $1248 for tires, what other hardware is needed to make RX8 competitive in BS? (I guess a set of konis, light weight wheels?) And how much?

Yeah you have the right car now. In T3 club racing the RX8 is the benchmark car, so SCCA will not touch the RX8 specs they just speed up or slow down the other cars in the class.

imho to set up a RX8 for BS: 245-35-18 Kumho V710s and Koni single shocks are the must have items. The front bar you can run the stock one, drill the extra hole in it or buy a bigger bar (most of them are around $200) depending on how you like your car. Icing on the cake is some lighter wheels, OZ is the best buy right now at 18 lbs.

For the track just buy some 17X9 wheels, then you can take advantage of all the used 275 and 245s out there. The only other must have for the track is some good brake pads.

Cooper47
06-14-2007, 07:52 PM
The Hankooks are a little cheaper... :)

I might actually consider trying them out if I can get a discount. Need to talk to the local contract driver.

Yeah, I'm tempted to give them a try but both times I've tried to get quotes or availability I cannot get in contact with their suppliers......I guess we've been spoiled with TireRack over the years and we may have to actually revert to talking to someone in order to purchase tires......I think I still remember how to do that:Wconfused

2nd thought.......I'm out on limb already with the Bilsteins. If I go with Hankooks and I'm still getting beat I'll be really bummed. At least if I have the Kumho's I know where I should be.

mwood
06-14-2007, 08:04 PM
^I'm just not sure there's huge upside in swimming upstream, or "bucking the system" ;)

TeamRX8
06-14-2007, 08:19 PM
^^lol

mp5
06-14-2007, 08:49 PM
2nd thought.......I'm out on limb already with the Bilsteins. If I go with Hankooks and I'm still getting beat I'll be really bummed. At least if I have the Kumho's I know where I should be.

Yeah, I don't expect the 'kooks to be as fast as the Kumhos. I have a pretty good idea where I stand as far as my driving goes when on equal equipment. My interest is just in having a cheaper alternative for some tires to run for the rest of the local season. As a bonus, we could get a chance to see how they stack up performance wise.

TeamRX8
06-14-2007, 09:21 PM
even scarier, spending all that and losing by 2+ seconds ... :cwm27:

Cooper47
06-14-2007, 10:02 PM
^I'm just not sure there's huge upside in swimming upstream, or "bucking the system" ;)

Did I mention I was cheap? Also, I like the excercise.

Imp
06-15-2007, 08:53 AM
And people laugh that I bought a Civic and sold the 8. :)

--kC
(Bought a '93 Civic Si for the price of 5 R-Compounds)

carusoracer
06-15-2007, 09:20 AM
And people laugh that I bought a Civic and sold the 8. :)

--kC
(Bought a '93 Civic Si for the price of 5 R-Compounds)


Fun car,fun class...Still need those expensive, eh hum "Street Tires":spank:
Most likely Bridgestones' from what I have seen and I'm sure you know what works best....

VASasha
06-15-2007, 09:27 AM
Wow that is some scary math.

Cooper47
06-15-2007, 02:25 PM
even scarier, spending all that and losing by 2+ seconds ... :cwm27:

Even worse, spend all your time and money on something that isn't even faster then a stock car on race tires......:uhh:

TeamRX8
06-15-2007, 03:11 PM
parts are easy to buy, skill not so easy ...

altiain
06-15-2007, 07:17 PM
The other alternative to spending a lot on a set of V710s for yourself would be to find a co-driver. There are plenty of people looking for a ride in a competitive car, and willing to pay for that opportunity.

dknv
06-15-2007, 08:54 PM
Scarier math:
Running both autox and track events - breaking your clutch at a pdx, and not arguing with the dealer about getting it paid for under warranty. Look up avg cost for clutch kit, plus $90 labor/hr x 6 hrs. Ow.

Turn around the next weekend (after the clutch is fixed ) - run a regional event x 2 days x 6 runs/day/driver (2nd driver = teenage daughter who is learning to drive a stick).

Next weekend - out of state event on concrete - leave some rubber on the pavement.

Next weekend - another regional event.

Repeat.

I think I have an addiction.

TeamRX8
06-15-2007, 09:38 PM
The other alternative to spending a lot on a set of V710s for yourself would be to find a co-driver. There are plenty of people looking for a ride in a competitive car, and willing to pay for that opportunity.


Unfortunately the large majority of wannabe-codrivers aren't willing to pay anywhere near enough when you consider what the actual costs of ownership are, and who pays when the car breaks ... my experience is that most codrivers end up being charity cases. Not saying that's a bad thing because I have given away my share of free or less than actual cost codrives over the years, but this is another area where the math can be just as scarey, maybe horrific if things go bad

Some drivers are stand-up people and pay for the motor they blew up, others have walked away and said "not my problem". WHo's to say if it blows up when you're driving that the other driver didn't cause it or vice versa. You can never really know for sure.

Cooper47
06-16-2007, 12:23 AM
Unfortunately the large majority of wannabe-codrivers aren't willing to pay anywhere near enough when you consider what the actual costs of ownership are, and who pays when the car breaks ... my experience is that most codrivers end up being charity cases. Not saying that's a bad thing because I have given away my share of free or less than actual cost codrives over the years, but this is another area where the math can be just as scarey, maybe horrific if things go bad

Some drivers are stand-up people and pay for the motor they blew up, others have walked away and said "not my problem". WHo's to say if it blows up when you're driving that the other driver didn't cause it or vice versa. You can never really know for sure.

I applaud the discipline by this group......I was sure we were going to get slew of "priceless" comments......I can just hear it now......Threepeat "priceless". :puke:

TeamRX8
06-16-2007, 04:36 AM
I'm talking from experience and anyone who has cranked the numbers knows it's true

sometimes a codriver can have tangible benefits such as showing you what the car is capable of or helping you figure out the course/line, there are times when it can be a distraction or even hurt, such as tires getting too hot

PDX_Racer
06-16-2007, 03:13 PM
I'm talking from experience and anyone who has cranked the numbers knows it's true

sometimes a codriver can have tangible benefits such as showing you what the car is capable of or helping you figure out the course/line, there are times when it can be a distraction or even hurt, such as tires getting too hot

Or leaving cones wrapped around mechanical parts...

(Not that I drove that well anyway...)

However, track days are pretty much $1000+ per weekend, assuming that you (or someone else) doesn't experience "brain fade" or decide to use your car as a brake.

If you think keeping your concentration at full for 60-90 seconds, try 20-30 minutes. Most mistakes at track days happen in the last session followed only by the next to last session.