Tires and mileage and does it even matter?

I have a 2013 R1200GS LC and just installed the Shinko 804/805 combo in the old 110 front and 150 rear sizes. Mathematically, it should have made only a 1.3% difference in diameter. Add in the wider LC rim width, and I figured it would have flattened it slightly and made the difference even less.

In reality, it made about a 5% change in the speedometer. My Nav IV used to say about 56 when the speedo said 60, now it reads about 59. I now realize my bike has about 5% less actual mileage than is reported on the odometer. Big deal? No? Who cares? Just wondering what y'all think.

You'll find that different tires, while having corresponding sizes on their sidewall, will vary in actual measured size from manufacturer to manufacturer. To paraphrase yourself, no big deal and I don't care.

If I understand correctly odometer readings are held to a different standard than speedometers, +-4% reported accuracy. If they have not be calibrated to deceive actual mileage they are deemed correct, Nissan won a judgement in 2011 on these grounds.

Care, nope sice all fall under this same "range of accuracy", in my simple reality that really represents zero. Speedometer and odometer threads can be as delightful as oil threads.

And, once upon a time BMW NA published a bulletin on "speedometer advance" to explain the reason BMW speedos always read high ... yes difference in size among tire manufacturers/models. The goal is to never display a speed slower than actual. The bulletin noted that the odometer should be accurate but in any event is the final say as to warranty eligibility.

Ultimately, U Get What U Pay For...

My 2 cents is we all have to decide on these factors: purpose & pattern, anticipated longevity, safety & wet-weather performance, and price. I'm frequently disappointed when I try something outside the norm, but then too I just might be pleasantly surprised...

FWIW, my worst experience was the Metzeler Karoo 3 tires on our GS twins. Our Best All-Purpose tire investment was in the Heidenau K60 Scouts that took us all over the country (including the successful 20 mile E->W passage on The Bureau of Indian Affairs Road #2 in the SD Badlands in slippery sand & interesting scenery) [start pt going west: N43° 28.671' W102° 52.638']. They took us a long way for a good price!!! Might not be able to mount them on my K-GT, but then I sure hope I can find something similar when we ride up to AK & the Arctic Circle.

You've installed Shinko tyres; hope U get what U want out of them...
CIAO, HSV-Phil

Accuracy

jandhumphreyme said:

If I understand correctly odometer readings are held to a different standard than speedometers, +-4% reported accuracy. If they have not be calibrated to deceive actual mileage they are deemed correct, Nissan won a judgement in 2011 on these grounds.

Care, nope sice all fall under this same "range of accuracy", in my simple reality that really represents zero. Speedometer and odometer threads can be as delightful as oil threads.

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I don't have a problem with a +-4% odometer tracking on my 2004 RT, as long as BMW gives the same range when handling warranty claims.

And don't forget the ol MOA mileage challenge. 5% of 40,000 miles is a pretty good amount.

sloengineer said:

And don't forget the ol MOA mileage challenge. 5% of 40,000 miles is a pretty good amount.

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That's my wife's long time complaint!

She is undercounted every year when she turns in her mileage sheet for her F650GS twin
- as compared to my current or last bigger BMWs... She rightfully feels Short-Sheeted!

She'll get her New Beemer one of these years.... Came close to buying a beautiful, gently-used 2016 R12RS in NVA; but she couldn't swallow that bitter Debt pill at that moment in time (when we were just entering the process of buying a splendid house and moving to HSV by ourselves)!

RPGR90s said:

I don't have a problem with a +-4% odometer tracking on my 2004 RT, as long as BMW gives the same range when handling warranty claims.

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Where I live BMW warranty is 3 years, unlimited kilometerage so plus or minus 4% matters not.