I recently upgraded my tires to Falken ST-115's to try and get around the terrible nature of the EL-42's and in doing so I stepped up to a slightly wider size, with the same profile.

I know I am reading just a little low as far as MPH is concerned, but I am sure this is throwing off my MPG calculation too for an entire tank full.

Is there anyway to reprogram the car to know what size tires i am running so that my readings and calculations are correct?

My friend has an 04 Chevy truck and suprisingly he was able to do this at a Chevy delaer.

Thanks in advance,

 

If you can't get it changed, you could do what I do whenever I get a new car. I get on the interstate, note the exact mileage at a mile marker, go ten miles, note the milage again, and do the math. This will give you a factor that you can apply to mpg calculations. I also do the same thing with the speedometer by timing 3 miles at a given speed, take the total number of seconds, divide by 3, divide 3600 by the result and you will have an accurate mph reading.

 

Stu E,
I am also considering the ST-115's to replace my HPT's when they are shot. The ST's are supposed to be very quiet. Is it true? Other items I am interested in are the ride, how they handle, and are they responsive. Also I plan to get the 245 section width. Any rubbing?
After you have had a chance to fully check your tires out, please give us a full review.
Thanks
Lakeman

 

I really don't know the answer to your question. If you have Navi I believe that there are some adjustments you can do in the Navi diagnostic menu (press menu, hold, press map and hold both and then press cancell and hold all three). I have no idea whether this is a good idea or a way to really screw up the Navi. I also have no idea if changing this would affect your speedo and odometer readings.

 

hey stu... just yesterday, i was watching some car show... and then the guy showed this small computer thingy.... that connects to your cars computer. saying that if wanted to get some of those hidden horses out of your car without buying accessories.. that was the best thing to get. that it redefined your engine, also you could adjust the gear ratio, fuel, i guess all the electrical computer stuff that the car has been programmed to do. maybe you could adjust it. And also mentioned that you could adjust your mileage when you change your tires and wheel sizes... WOW i cant think of the name.. hold.......................

 

sorry cant rememeber. But these guys should know watt i am talking. They are those computer things with a long cable, that connects to the cars PC.... and then you could go into details on watt its programmed and re-fine tune it.. to get better performance and adjustments... for example all these guys changing the resonators,, maybe could adjust the flow of fuel or watever... you have to look more into details but this TV car show. . did alot to car....

 

A change from 235/45-17 to 245/45-17 would result in you being about 1mph off at 65mph. You will be going 65 mph but the speedo will show 66, not a great difference.

 

http://www.acura-tl.com/forums/showt...=73974&page=10

It is in the long post where "carcar" list all the features. You can also go to the FAQ thread and link from there.

 

roadman is right. It reads 65 and you'll be doing 66. I think someone actually did the math and it was like 65.6xxx or something. Not that big of a deal. Besides, most speedometers have a margin of error of plus or minus 1 mph. I say MOST, but not all. I'm not sure what the TL's specs are.


I used to calibrate electronic measuring equipment for a major electronics company and know that every unit is not dead accurate from the factory until it is adjusted by a qualified technician.

So the bottom line is....don't worry about it, because I have the same tires coming on Thursday of this week

-Chad

 

I think if you've got NAVI you hold down Map/guide+Menu+cancel for 3 seconds to get into the diagnostic mode and there's a place to caliberate your tires for size and stuff.

 

i wasthinking about getting 19s for my car and was reading the manual that it might effect the stability control negatively... I wonder if i brought it into the dealer, whether or not they could recalibrate everything

 

No way to change it. But if anything you will be going faster.

 

people are right - you can adjust for tires in nav system. not sure if you don't have nav...

 

and you can't adjust your "gear ratios" with the OBD reprogrammer. Fuel ratio maybe, but gear ratios are a little bit harder, physically

 

Lakeman,

I really like the ST-115's. They are the quietest tire I have ever owned and they handle quite well. Note the sound your stock tires generate going over the bots dotos int he road and notice how quite the ST-115's are doing the same thing. I have not had the chance to drive in the rain with them yet, but I have read in other forums that they are very good in the wet.

There is no rubbing with the 245/17's. what so ever. I had them Road Force balanced, but I appear to have some flat spotting in the moring, but MUCH less that with the El 42's. I notice the slight shimy for about 2-5 mins of non-freeway driving. Why does this happen? I have never had a car or ties with this issue before!!!

In my opinion, this was a great update. In fact, the steering feels like it is weighted a little better than with the stock tires. The car is also much less darty than with the original BS's. Handling in general, is much improved.

For the price and the apparent quiality, I don't think there is a better tire for the money right now.

Any other questions, let me know and I will attempt to answer them.

Take care and thanks for all of the feedback to my question,

Stu E.

04 Satin Silver/Ebony Venture/Xpel Clear Bra/Falken St-115 245/45/17's

 

That has nothing to do with the speedometer or the odometer of the car, is just for the navi.

 

Easiest way I know of to get a very accurate measure of the accuracy of your speedo is to take a hand-held GPS in your car and compare the readout to the speedo.

 

Stu - Thanks for the feedback on the larger 115s. This is EXACTLY what I plan to do in the near future. The car in general is so quiet, I want to reduce the noise even further with better tires. The improved handling will also be appreciated.

What did you pay for the larger 115s?

 

Automophile,

I paid 128.95 for each tire at American Tire (Discount Tire). This included mounting and balancing and and I was only given $140 for all of my EL42's. I chewed them down a little on the RoadForce balancing to $9.00 each wheel.

All in all, I am enjoying the car much better. Once you get your ties, let me know if you experience any flat spotting in the morning and how you like them.

If you have any other questions I can help you with, let me know.

Take care,

 

On my old vehicle (Benz C-class) I went from stock 15 or 16 inch tires (215?) to 18 inch low pro's that were like 245's. This still did not affect the speedometer more than 1 or 2 MPH maybe. As far as the diagnostic screen, I'm not sure if you could handle something like that through there. For ECU for performance gains, I'm positive you could tweak it, especially since dyno's of our car show the power is still increasing when rev limiter kicks in,

 

The tire size, for example 235/45 R17 (OEM for TL) is read as 235 mm thread width / 45% of 235 mm tire wall height, and 17 inch wheel radius. The 45% of 235 mm is 105.75 mm. If you have 245/45 R17 it means the tire is 245 mm wide and 110.25 mm tall from the rim. 17 inches is equivalent to 431.8 mm. The resultant radius of your wheel and tire combination is 110.25 + 431.8 +110.25 = 652.3 mm, and the length of it's circumference is 2048.222 mm. The radius of the OEM tire is 643.3 mm and the lenght of it's circumference is 2019.962 mm. Basically you are traveling 28.26 mm more per tire revolution.

According to the Tirerack's spec. sheet for the Potenza RE030 (OEM in my car) the tire does 817 revolutions per mile (don't really know where they get the number from). So, while traveling 60 mph, the tire will do 817 revs. per minute, or 13.617 revs. per second. I guess that is the calibration of the car. Since in every rev you put 28.29 mm more of linear distance you multiply by 817 rpm and get the total extra length traveled by your car every minute, 23,088.42 mm or 0.0143465 miles. In an hour, just 0.8608 miles. So, you would actually be traveling at 60.8608 miles per hour. This will also affect you average MPG. Same fuel for more distance traveled.

Of course that is on paper. Other variables like remaining tire wear, particular tire construction, sidewall strenght, and air pressure could influence overall tire diameter.

Just my $0.02.

 

Take it to the dealer, they can adjust it by hooking it up to the Honda HDS Tablet (if they have one)It will be easier to figure out how far it is off first and then tell them to adjust it up or down. Typically there may be a 4-6 mph window at 60 mph.