I changed from 195/55-16 tires to 205/50-15 tires. This is about a 6% change in the speedometer (and I assume the odometer as well). I don't want to rack up more miles than I'm actually driving.

Does anyone know if there is a way to adjust the speedometer calibration to adjust for the difference in tire size. I know there is a gadget for Hondas called a yellow box which fools the ecu. Is anything available for the Mini?

Before I get flamed:
1. I know most people say to limit the tire change to 3%
2. I have searched for the answer

 

dealer can fix i believe.

205/55/15's wont change the speedo at all, shoulda done some research at a tire shop, they can tell you what will fit. or even get a measuring tape to match heights.

 

i just did another calculation

205/60/15 would be the best choice, less than +/- .75 MPH difference from 35-65 MPH

 

That would be way too tall of a sidewall. I bought for performance, not to match the old tire height.

I ordered these 15" wheels and was planning to put on 225/45-15 R compounds for track use only. When I got the wheels, I decided to put a summer performance tire on this year and worry about R compounds next year. I want to use them on the street this summer because the little 15" wheels look cool, but don't want to rack up unnecessary miles doing so.

 

I think the best idea would be to go to the dealership aswell. They can probably calibrate it properly.

 

Tests 1 and 2 are always unlocked in the IKE

read up on it here....

http://www.mini2.com/forum/faq.php?f..._obc_functions

the setting 1.1 is called "Kilometer Count"

However in the document from minitechinfo.com (called "08b_MINI Body Electronics.pdf") it is described as;

K-Factor
Tire calibration

There is not additional information in the document on this or I would mention it here...

It looks like the setting would be done simular to the fuel consumption adjustment described here... again from the www.mini2.com faq

" 20.0 Correction factor for Fuel consumption
Formula for correction:
Shown consumption x 1000 / user defined consumption
Push the trip reset button to begin the correction. Numbers count up from 0-9, when correct number shows push trip reset button.

20.1 Sets 10ths. for consumption factor
20.2 Sets 100ths. and 1000ths. for consumption factor
20.3 Saves the new consumption factor and shows new value "

But the point is you should be able to set this without a dealer, or any special equipment....

send me a pm if you figure it out.... or post it here for others....


BTW guys.... test 2 is really fun at night - try it!!

other test numbers will display battery voltage, fuel sensor readings (there are two), rpm, temperature, on and on.... fun stuff !!

Good Luck

 

I went with a 205/60/15 on a OEM wheel. I knew I was sacraficing cornering capabilities but I was convinced that I was doing this car a favor with a softer ride. I have an 02 MCS with 10600 mls and not one rattle, squeek or vibration and I would like to keep it that way as long as possible. Besides, it'll still go thru a corner faster than I care to go.

But yes! A 60 series tire is to tall for maxium cornering performance. But I fiqured it would still be a better performer than the 175/65/15s that come standard on the MC.

Anyway, maybe this link will help.
http://www.1010tires.com/TireSizeCal...?action=submit

 

Flip,

I've got the 175/65/15s (with SS+ too) and the car is still a MINI and corners great. So, going to 60 series with a wide tire like 205 will be much much better than the stock arrangement. So, don't fret too much having the higher profile tire. I remember having a '73 Dodge Challenger that I upgraded tires/wheels to a wide 60 series tire (stock was 70 series) and chrome slotted wheels, and that was awesome, along with air shocks on the back which jacked it up and it was sweet! So, everything is relative............ what is fine today can be outdated tomorrow.

 

The 6% difference you quote may not be quite that high if you look at this a little differently. I think the standard tire/wheel width is 24" for the MINI. Some stock tire/wheel combo's are slightly more than that and some are slightly less, but I'm guessing that 24" could be the goal or the normal setting that MINI designed the speedometer/odometer around. We'd have to verify that with someone to be sure. So, given that, then 205/50/15 has a diameter of 23.1" which is just 3.75% smaller diameter than 24" (.9" divided by 24"). This difference may not be enough to want to bother with changing the speedometer/odometer. Sure, if you can do it, then that's a plus as accuracy is important for a lot of reasons. With the smaller diameter you get the benefit of lower gearing giving your car more quickness off the line and also increases the rpm's slightly to put you in a higher rpm (power) curve.

 

enjoy the 205/50-15... don't worry about the mileage.. it is 6k extra per 100,000 miles driven (at 6%) and you will probably only use those tires and wheels for about 30,000 miles, which equates to a 1800 miles extra.. I would worry more about protecting the underside of your front end which is now about a 1/2 inch lower... and if 3% is considered OK, then it's really 6k extra at 6% less 3% (3k) so difference that is over acceptable is 3k per 100k (6k-3k)....

enjoy the ride and lower gearing.. burn out those 205/50's at the track.....

 

Can you put this into a mathematical equation, please?

 

Oh you! Asking for "the numbers" is so "10-Minutes-Ago" .

 

This may or may not help at this point, but a good reference for anyone needing it. http://www.miata.net/garage/tirecalc.html

 

more of a function:

if 3 % is an max acceptable tire circum difference from stock... then per 100,000 miles, 3,000 miles would be the inacuracy of your odometor which is considered acceptable difference as defined by +/- 3% times 100,000 = +/- 3000 miles.. if you had a tire to big by 3%, then your odometer would be 3% too low in milieage

if your off 6% then your odometer would be off +/- 6,000 miles per 100,000 miles traveled ... 100000*6% = 6000 miles... but really your only 3% more than the acceptable

So if limit of being off is 3%, and your off 6%, then your over the limit by 3% only so if your using these tires for 30000 miles

+3% (30000 miles) = 900 miles extra your mileage will show

or using the 6% simple function then 6% times 30,000 miles = 1,800 miles

 

Thanks for that link !! I will have to give it a try

 

wait until after dark to do the test 2....

it is almost like a video game

 

jazmini,

I have two freinds who own classic Minis and they are running a 70 series tire. (These guys do things by the book and their Classic Minis are excellant). Of course, thats on a 10" wheel, but still, they can probably out corner my 02 MCS.

I use a tire calculator called 10-10.com. Any time a different tire diameter of more than 3%+/- is calculated it puts up a warning about possible brake failure.

I don't really beleave that, but than again, I would'nt want to learn the hard way. I do beleave that you will probably experence excessive/rapid brake or tire wear.

 

It was a cool test, the link to minitechinfo.com is broken.

Is there are more information about these menus.. I want to know more !!!

 

aww, i live the test mode, thats awesome, lots of cool info!

i was hoping the speedo would test too!!!

 

Flip -- That's good to know that the calculator is focused on that 3% difference -- I wondered where that came from. There are many people running the 205/50/15s which are maybe 3% or so off. Many run them in autocross and track, so it would be hard to specifically say if they were having excessive wear. I'm personally not worried about a little extra wear (when I get around to upgrading). :smile: I just love the classic Minis too!

 

hahaha where did u get that rap test 1 is to reset the sia *(oil change light) test 2 is a kombi self test goofy u will need to unlock it to get anything done just bring it in