mtd blade width bagging/non bagging

[38racing]

I have an MTD 134h451F...(38" deck) and the IPL calls for 742-0473a blades. IPL for a similar model even states it is 3" blade. When I look it up from my aftermarket supplier I get 2 different blades. It says to use two 3" blades for bagging but for no bagging it says to put a 2" blade on the left and the 3" on the right. This unit is only 12.5 and manuals for this model type don't mention bagging.
I won't be bagging but plan to use two 3" blades as per IPL. What would be the theory behind suggesting different width blades for non bagging? Did they mix it up and maybe meant using the narrower left blade when bagging? There may be MTD bagging models using same blade(s)but different widths?
update: just found this mtd link
http://support.mtdproducts.com/app/answ ... ing-blades
near end it does say
*BAGGING KITS - generally consist of a bagging catcher assembly and may also contain optional 2/1 blade(s) for enhanced bagging performance.
which still leads me to think aftermarket may have it backwards.

[bgsengine]

I have an MTD 134h451F...(38" deck) and the IPL calls for 742-0473a blades. IPL for a similar model even states it is 3" blade. When I look it up from my aftermarket supplier I get 2 different blades. It says to use two 3" blades for bagging but for no bagging it says to put a 2" blade on the left and the 3" on the right. This unit is only 12.5 and manuals for this model type don't mention bagging.
I won't be bagging but plan to use two 3" blades as per IPL. What would be the theory behind suggesting different width blades for non bagging? Did they mix it up and maybe meant using the narrower left blade when bagging? There may be MTD bagging models using same blade(s)but different widths?

Its the difference in blade lifts that does the trick - less lift on the 2 inch blade makes the air flow better to the right side for the bagging operation.

[38racing]

I have an MTD 134h451F...(38" deck) and the IPL calls for 742-0473a blades. IPL for a similar model even states it is 3" blade. When I look it up from my aftermarket supplier I get 2 different blades. It says to use two 3" blades for bagging but for no bagging it says to put a 2" blade on the left and the 3" on the right. This unit is only 12.5 and manuals for this model type don't mention bagging.
I won't be bagging but plan to use two 3" blades as per IPL. What would be the theory behind suggesting different width blades for non bagging? Did they mix it up and maybe meant using the narrower left blade when bagging? There may be MTD bagging models using same blade(s)but different widths?

Its the difference in blade lifts that does the trick - less lift on the 2 inch blade makes the air flow better to the right side for the bagging operation.

So maybe aftermarket has it backwards saying two 3" for bagging. Makes sense since I have never seen a MTD regular non bagger with anything but both blades identical.

[bgsengine]

I have an MTD 134h451F...(38" deck) and the IPL calls for 742-0473a blades. IPL for a similar model even states it is 3" blade. When I look it up from my aftermarket supplier I get 2 different blades. It says to use two 3" blades for bagging but for no bagging it says to put a 2" blade on the left and the 3" on the right. This unit is only 12.5 and manuals for this model type don't mention bagging.
I won't be bagging but plan to use two 3" blades as per IPL. What would be the theory behind suggesting different width blades for non bagging? Did they mix it up and maybe meant using the narrower left blade when bagging? There may be MTD bagging models using same blade(s)but different widths?

Its the difference in blade lifts that does the trick - less lift on the 2 inch blade makes the air flow better to the right side for the bagging operation.

So maybe aftermarket has it backwards saying two 3" for bagging.

Nah - just cheaper and more efficient. Bagging blades will have higher blade lift to increase air flow, the difference in blade lifts in OEM by design is a minimal improvement, but can be quite noticeable in heavy grass... thus OEM would engineer with performance in mind, offset by safety (High Lift blades = more air flow = more discharge velocity which would be undesireable in a side discharge, thus OEM non bag blades won't have high lift) while aftermarket "will fit" is engineered with PRICE in mind. - Also keep in mind the aftermarket blades may be engineered differently - you might have the low lift blade being the 2" and the high lift being the 3" - its not so much the blade width as it is the amount of LIFT (the "propeller" function of the back of the blades)

Makes sense since I have never seen a MTD regular non bagger with anything but both blades identical.