Hey all I recently had 17" tires on my MCS and I know the speedo was off by about 3mph....I have a GPS and it was always 3 mph slower then what the MINI was showing. (I tested the GPS on multiple vehicles and it was allways showing correct speed, some threads on this)

So I got snow tires on, 15" and its way ,by 5mph now. Its kinda annoying but I guess I'll have to live with it......Smaller tire....faster it goes round, faster car thinks I am going.....Now my GPS says Im doing 70 and Mini shows 75 on digital speedo and allmost 80 on the BIG speedo.

Will this correct itself or can MINI fix this for me in the computer? Also Will this affect the miles being adde donto the car with the Odometer.


Thanks.

 

Did you buy different tire sizes than the usual OEM 15" and 17" sizes? If so, that might be the reason for the larger discrepancy.

 

I had the 17" 205/45R17 Stock runflats on there when I got the car....then for winter tires I got 195/66R15 Tires.

 

The MCS is calibrated to work with the 17" and the 16", that too the OEM sizes. If you use something else, it'll be off, especially since with the 17" OEM it is already slightly off.

 

I see since the 2 sizes you can get witht the mcs are 16 and 17.

So MINI cant adjust computer?

 

15" fit?

 

195/66R15? I gather you meant 195/65R15. That's likely your problem then. The OEM tire sizes are:

175/65R15
195/55R16
205/45R17
205/40R18

If you deviate from any of those four sizes, you potentially will reduce your speedometer's (and as a result, your odometer's) accuracy than they intended (unless you're very careful to find another size with the same circumference).

Let's use a tire size calculator - one of the most popular ones online is from Miata.net (note: ignore the fact it's a Miata site, the calculator works for all tire sizes):

Miata.net Tire size calculator

Looking at your new size, let's compare with your stock 17" ones. Punch in the two sizes, and you get these results:

Stock tire (205/45R17)
Sidewall: 3.6"
Radius: 12.1"
Diameter: 24.3"
Circumference: 76.2"
Revs/mile: 831

New tire (195/65R15)
Sidewall: 5.0"
Radius: 12.5"
Diameter: 25"
Circumference: 78.5"
Revs/mile: 807

And the summary:Now, if you'd gone with the OEM 15" size of 175/65R15, the summary would have been:See - it will almost never be exactly the same, but the stock size is only 1.3% off than the 17" OEM size, but your choice is 3% off (in the other direction).

 

I didn't know you could fit 15" wheels over the brakes on an R56 MCS. What brand/model wheels are they?

 

Im curious as well?

 

That's a very good point... the larger brakes on the R56 MCS should be a limiting factor. Obviously not an issue on stock R53 MCSes though...

The OP said MCS, and posted in an R56 forum, but didn't actually say it was an R56. So one possibility is that it's actually an R53 and was posted in the wrong forum...

Either that or there actually is a rare aftermarket 15" wheel that fits the larger brakes?

 

Check his gallery, he def. has an MCS.

 

We knew he had an MCS for sure (his post said "MCS"), it was only a question of which generation. Good call, the gallery clears it up before he did.

Back to Robin's original question then - what 15" wheels does kevinminict have that fit over his R56 MCS brakes?

 

A little searching on this very forum would tell you the answer: Tirerack.com's Sport F2 15" *may* fit. I have those wheels, but on an R56MC.

 

Check here.

https://www.northamericanmotoring.co...9&postcount=10

 

195/60-15 would be closer to 205/45-17 in overall diameter.

 

Sure would - within 0.2%! (24.3" vs 24.2")

 

I guess the speedo is just off period then huh? I've seen other threads where people have complained that it is not that accurate.

 

Sorry havent been on....yeah I have 15" on my MCS!! Got them from tire rack. Check my flickr gallery for phtos of the brake clearance. http://www.flickr.com/photos/12405782@N02/

Yeah I meant 195/65R15 My bad. I dont't mind it being off when I had the 17" tires on it was about 3 mph off......but now it 5mph off its kinda annyoing and I was just wondering if there was a way to fix it via computer. And also just wanted ot know if it would affect mileage on the odometer.

 

I was shopping for winter tires and wanted cheap steel wheels. I have a 07 COOP S, according to the Dealer 15s wont fit due to the S brakes larger size. Just to understand, you ordered 15s? For your S?

 

They wont let us do that in Germany. Dain, thats close!!!! Nice job

 

The "normal" ~3% speedometer error doesn't affect the odometer, but the extra error you're seeing from the non-standard tires will affect the odometer.

You'll have a hard time getting the dealer to adjust the speedometer unless you're outside the allowable specs. Even then, you'll likely have to pay to have it done if it's your choice of tires that put the speedometer out-of-spec, rather than a problem with the speedometer itself.