SCOOTCHNC - THANKS FOR YOUR INPUT - BUT I DO NOT SEE EXPLANATIONS OF WHAT THE ALPHAS MT, MU, MV, MR and MM EQUATE TO NUMERICALLY - FOR EXAMPLE CAN YOU TELL ME THE DIFFERENCE BETWEEN THE MR90-18 & THE 130/70-18 FRONT TIRES IS?

 

I have never seen anything that explains those M codes, but you will see they also have a numerical code with them. So in the table Scootchnc gave us MT is also 72H, or 74H. Wikipedia explains them if you search on 'tyre code'. The bigger that number the higher the load rating in pounds.

Harley stock front and rear tyres on our bikes are MT with 74H at both ends. Later dressers have an MU 77H rear tyre. The H is the speed rating, 72 has a load rating of 783 pounds, 74 means the tyre is 827 pounds and 77 is rated at 908 pounds.

 

Ok grbrown - if i get ir right the mr90-18 with a 71h is a better choice than the 130/70-18 with a 63h - correct? How do you know which has the lower profile?

 

Most of the M series tyres I have seen are 90% profile, while the 130/70 is 70% profile. I think that is what the 90 in MR90 means! I think you will find I may only know a tiny bit more than....

 

Thanks grbrown - that tiny bit helped alot

 

Pleased to help.

 

the ALPHA is a hold over for a long time ago.... when a car tire was called F-78-14 or?
F=width of the tread 78 = sidewall height as a percentage of tread width, 14 being the wheel diameter. As Radial tires became more common, tires were simply labeled in metric measurement. But the same RATIO remained
Tire WIDTH/sidewall height/rim dia

this same thing applies to motorcycle.
now as you can plainly see, the Dunlop chart is in INCHES... thus you have
150/80/16
150 mm tread,
120 mm side wall (150 x 0.80)
16 inch rim

1 inch is roughly 25.4 mm which means that 150 mm = 5.9 inches... AS SHOWN on the tire chart from Dunlop

the first M= motorcycle
MT/90/16 equates to 133mm/90/16 +/-
MR 120
MM 105
MV 153
MU 141

MR is 120 while a 130 is..... well a 130
Or... as stated on the chart... a MR= 4.7 inches, while a 130 = 5.0 inches


You can do the MATH on any tire/brand, as long as the brand supplies width (and they all do)

The MR/90 means the SIDEWALL of the tire is 90% of the width... or??? 120mm wide, x108mm tall
a 130/70 would be 130mm wide x 91mm tall

H= speed rating.... the 71, 61 etc... all relate to LOAD rating... the bigger the number... the greater the load rating
Here is a chart to explain that
http://www.tirerack.com/tires/tirete....jsp?techid=35
(yes.. that chart is indeed a car chart... but ratings are ratings, and they are uniform

 

http://www.avon-tyres.co.uk/motorcycle/cobra

if you use the accepted 25.4 mm =1 inch.... the only Alpha tire works out nicely

http://www.unitsconversion.com.ar/le...meter-inch.htm