chikai

I just made a long a$$ road trip from Pittsburgh to NYC this weekend. I drove exactly from my apartment to 48th street and back...no side trips, no deviations, nearly nothing.

Mapquest calculated the trip to be 740 miles round trip. When I got home last night I had exactly 800 miles. Now I did make a few circles around the block in NYC trying to find parking. And add some rounding errors by mapquest...so add probably another 5 miles. So I'm looking at a 7%-8% error from the exact mileage.

Why the high error...because I just got the 215/50/17 Sumitomo HTR+. The revolutions per mile on that size is 829 (according to tirerack). The stock 215/50 Michelin is 819. That should calculate to a 2%-3% error.

At one point on the turnpike I also tried resetting the tripometer to match the 1/10th mileage markers to caliberate the speedometer. By 9 miles my tripometer was 2/10th off (I was bored!!!) By that calculation it's not so bad, but it's still quite off.

Is there anyway to recaliberate the speedometer/odometer or is it set into our computer?

BTW: I got a B.S. speeding ticket. I was following a white van doing 80mph. The cop was sitting behind a underpass and clocked the white van. He pulled both of us over...told me I was doing 85mph (no way in HELL!) But he was trying to be nice and gave me a ticket that said "exceeding PA speed limit" with no mph on ticket which = no points. Bastard! I know he didn't clock me.

jimcol711

yup, you just effectively lost 50 miles off your warranty...how does that feel?? and every day you keep those tires, the loss will continue, this is the exact reason why i am very hesitant to get new tires that arent an EXACT RPM as the stock tires...i dont want my warranty expiring a few thousand miles early....fuck that

louisn

I came up with a 1% difference between the two tire (819 divided by 829) which equals to 500 miles less on the warranty if you put the sumitomos on as soon as you bought the car. The increase in performance and ride are well worth the small decrease in warranty IMO.

Bluto

Another intelligent post!

Why not get larger tires to extend your warranty?


chikai

Mapquest is not accurate. As tires wear the rpms change. If you are worried about the warranty, go larger next time. I don't think there is anyway to adjust the speedometer/odometer.

JRock

Oh wah wah wah. I have 225/45s and I have 41k on my car. Think I'm sweating about running out of the next 9k miles of warranty just a little faster? Hell no. That's life. Buy an extended warranty if you care that much.

jimcol711

go ahead, laugh it up or whatever, but its true, fuckin a, if you put on some 215/65/17 you could probably get at least another 2000 miles of warranty and keep your mileage low in the process....when it comes down to things like our cars SHITTY RESALE VALUE, every mile counts!! keep it low, or expect an anal rape when you trade it in or sell it.

Zapata

Moral of the story.........buy yourself a V1.

Nicky Pass

EXTENDED WARRANTY!

chikai

to be honest with you I really don't care about the warranty. The car will be gone before it expires. I have 16,000 on the car now, I don't put more than 12,000/year.

I have to say the performance gain is definitely worth the extra mileage. During the 8.5 hour (normally 6 hr) drive I went through three severe snow storms. At one point I couldn't see the taillight of the car that was 3 car lengths in front of me. I had literally 10 feet of visibility. The Sumitomos kept me safely straight and stuck when I braked. I know the Michelins would've been everywhere.

The reason I went w/ the 215/50/17 Sumitomo's were:
1) I heard people were having balancing issues with 235/45/17 which had a closer rotation/mile
2) I read great reviews about the Sumitomos and at $89/piece...can't beat that value.

chikai

also since my revs/mile on my tire is higher, shouldn't my speedometer read higher than it is.

ie: if my speedo says 80mph, I should be clocked by radar like around high 70's?

jimcol711

yes, your speedometer will also be off as you described

chikai

damn pig I knew I wasn't going that fast.

I can't even really contest this one considering I was caught 4 hours from where I live. Oh well...

CO-CL-S

Shortly after getting my car I did a test against the Interstate mileage markers (for a few hundred miles), and also against a GPS. The both indicated my stock setup was off 1-1 1/2 %. YMMV

jimcol711

you are absolutely correct on this...acura fucks us from the beginning by selling cars with speedometers and odometers that arent accurate to begin with.

when i drove to milwaukee from NYC back in april, my car was virtually brand new, i had MAYBE 1500 miles on the car at the beginning of the drive, so the tires HAD NOT had any chance to start to wear down. over the course of the 918 mile drive, my cars odometer racked up an additional 22 miles, that means that the car is already off by about 2-3% from the factory...even on brand new stock tires, our speedometer is off, so if you guys that are going from stock tires to 225/45's arent just the 2% off from the stock size, but you are abtually closer to 3-5% off OVERALL because its been shown by a few people, including myself that our cars with stock brand new tires are already fucking us out of our warranty....



considering the margin of error on the brand new stock tires, over the course of driving an ACTUAL 50,000 miles, your odometer will show an extra 762.5 miles, now that number doesnt even take into account the fact that over time, the tires wear down, so that number will actually be closer to 800.

With stock tires, you are losing 800 miles off your warranty. Now you guys with your 225/45's...you are at LEAST doubling that loss if you put the 225/45's on very early in your ownership....so you are losing in the range of 1600-1800 miles off your warranty if you were to put on 225/45's from day one.

do you really want your warranty to expire when your car has really only driven 48,000 miles?? do you want to lose that mileage off of your lease? and have to pay the penalty because your stock tires fucked you over?? im always surprised that not many people realize the severity of this and dont make a big deal out of it...its not as small of a situation as people blow it off to be....we arent talking about a small number here, 1800 miles is alot, and if you keep your car for a longer time, you have the potential to rack up 4000-5000 extra miles, so when it comes time to sell your car, that extra 5000 miles is going to effect your resale value....


there may be something to be said about getting TALLER tires, even if it may alter performace (in a nearly insignificant way, definately not noticeable while driving or anything) you could effectively slow down your odometer and increase the length of your warranty.

Tom2

Car and Driver had an excellent article on this a while back....

They tested American, German and Japanese vehicles (not just one each, but an entire grouping of each) and determined that ALL 3 have inaccurate speedometers. I don't remember the exact numbers, but I do remember that American vehicles were the most accurate, followed by Japanese. The Germans (especially BMW) were off by the most. At a true 70 MPH, the German cars averaged an indicated something like 72.4 MPH.

So it's not just Acura.....they ALL do it.

They also mentioned that American car comanies follow the Society of Automotive Engineers requirements for speedometer/odometer accuracy. The have fairly loose specs.

Also, they claim that the difference between a brand new tire and the same tire worn out can be as much as 2-3%, if I remember correctly.

Nashua_Night_Hawk

Just drive it.... the gains from 40 series tires and wider tread are worth it... I like my 18" setup... would love to have light rims too..

Tom2

jimcol-

Have any pics of your car? I'd like to see the Evo5 on a CL-S. I've always like those rims.

jimcol711

wow!! so essentially, this means that:

the difference between our cars being 100% accurate and a worn out 225/45 would be like 7-10%!!!!

because youve got the initial 2-3% error, then the 2-3% error because of the smaller size, then the 2-3% error of the "wear-down"!!

now are you guys starting to understand???!?!

with those numbers, you could easily lose 5,000-7,500 miles off your warranty/lease or MORE!!!!


jesus christ, i think im going to get some 225/75/17's!! i want my warranty back!!! (too bad they wouldnt fit without a 4" body lift!!

Slimey

I know that some have suggested the speedo is actually calibrated to the 205/60-16 of the CL-P. The rollout of that stock tire is 813 rev/mile while the CL-S Michelins have a rollout of 819 rev/mile stock.

I would trust the mileage markers more so then mapquest for mileage/speedo estimates.

I thought that your speedo/odo can be calibrated if need be (by a mechanic). I'm not sure about the Navi but there is a hidden diagnostic mode that you can get to if you want.

Chikai - how can you get a ticket without some MPH estimate on it? How do they know if they should charge you/prosecute you for being 5 MPH over the limit or 100 MPH over the limit? It does not sound appropriate to be 'speeding' without defining what that was. Seems like it should be challenged.

mr. big

so u are saying that if i have 235/35/19, my warantee will be up quicker? how? becasue i will still have the same mileage on my car...the mileage doesnt go up faster than usual. Plz explain this to me. Also, will i be going faster than normal?

jimcol711

without getting to into it, a cars odometer works on a mathematical calculation. It is programmed to understand the distance of exactly one mile according to a certain overall tire size (circumfrence)

your car adds a mile to your odometer everytime it registers your wheel/tire turn a pre-programmed number of revolutions..on a CL-S this is something near 820 revolutions per mile....if you DECREASE the overall circumfrence of your tires by even a tiny amount, you are throwing off that calculation. now your tires need to (as an example) revolve 834 times in order to reach a mile but your odometer still is programmed to add a mile every 820 revolutions, so now your car has gone an extra 14 revolutions per mile and your car starts to count those 14 extra revolutions on the NEXT mile even though they are actually still part of the first mile it just added to your odometer...it doesnt understand this descrepancy.

....you add that up over time and you have hundreds and/or thousands of extra miles, depending on the actual difference between the programmed about of revolutions and the actual revolutions it takes to go exactly 1 mile.

ALSO, this effects your speedometer because that also works on the same principle...if you decrease the overall size of your tires, your car thinks you are going faster than you really are....so now when you are actually going 70 mph, your speedometer says you are going 73mph...even though you are really going 70 mph.

does that make sense???


bottom line is that if you alter the overall size of your tires, you are either going to be slowing down your odometer or speeding it up....your choice.




does that make sense???

lou_RENAMED

Moral of the story get yourself Michelin A/S in 235/45 17 with only 811 revs compared to 819 revs stock

JRock

Wow dood, you shouldn't have bought an Acura. They just fuck with people. No good lousy bastards. We need to storm their castle with stakes and torches. Next thing you know they'll be fuckin' ya with the cell phones. Kill kill kill, I say.