Real octane number
- Thread starter wscycle
- Start date
er. 
depending on country... label should be the R+M/2 number...
RON is just research octane number(always higher), MON is motor octane number(always lower)..
the label octane is a basic average for use in comparing fuel octanes due to this difference...
when people say i use "91 premium" normally in the United States that would mean they use R+M/2 91...
as to which you should use, i would say R+M/2 as it takes into account "bad conditions" like high heat and stresses, into the octane rating...
certain high RON octane fuels due to vapor pressures etc. are actually very poor MON fuels.... this is why fuels are always a mixture of various things rather than straight one thing or another...
my .02
RON is just research octane number(always higher), MON is motor octane number(always lower)..
the label octane is a basic average for use in comparing fuel octanes due to this difference...
when people say i use "91 premium" normally in the United States that would mean they use R+M/2 91...
as to which you should use, i would say R+M/2 as it takes into account "bad conditions" like high heat and stresses, into the octane rating...
certain high RON octane fuels due to vapor pressures etc. are actually very poor MON fuels.... this is why fuels are always a mixture of various things rather than straight one thing or another...
my .02
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Here at Road Atlanta you can gas up with 4-5 different Octane choices. I fueled up with 110 or something (forgot exactly, but it wasn't the highest). Cost me $30 to fill up too. Figured she deserved it just that one time....
R+M/2 is a good number. If you can't get that look at the MON number. After you get over approx 105 octane all of the gasolines will have lead in them. So, don't run a leaded gasoline in a bike with a catalytic converter, as it coats the converter and stops it from burning any exhaust gas.
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