straight vs helical cut gears
#12
09-08-2010, 10:00 PM
Harley reasoning was that "straight cut" gears would be used in 1st and 5th gears because they are inherantly a little stronger than their "hellical" counterparts. I don't particularly subscribe to this notion but I am not a Harley Davidson engineer either. Launching a heavy motorcycle takes a stout first gear so their reasoning was to use a straight cut gear. Since touring bikes spend quite a bit of time in 5th gear accelerating, once again their reasoning was to use a straight cut here again. They never counted on the thousands of riders who bought new bikes complaining that they believed their transmissions were failing. The easy fix was to change out the Harley transmission oil to a real gear lube such as 75/90 but dealers usually don't recommend another competing fluid. Anyway, second, third, fourth and six gears all got hellical gears. Tired of all the complaining, Harley engineers changed all the gears to hellical for the 2010 year. This continues in the 2011 models as well and the complaints have stopped.
#15
09-09-2010, 08:03 AM
This mostly sounds like marketing hype to me. Thanks all for the great information though. Much appreciated.
#16
09-09-2010, 10:07 AM
"Marketing hype"? I don't think so. The MoCo had to go to helical gears in response to customer whine about gear whine. Helical cut gears impart a lateral thrust to each other which will put additional stress on the shaft bearings and cases, which will require design modifications to the afore-mentioned components. That's seems like a lot of expense for a little "marketing hype". I don't have a problem with normal gear whine.
Last edited by RK4ME; 09-10-2010 at 11:53 PM.
#19
09-09-2010, 07:37 PM
"Marketing hype"? I don't think so. The MoCo had to go to helical gears in response to customer whine abour gear whine. Helical cut gears impart a lateral thrust to each other which will put additional stress on the shaft bearings and cases, which will require design modifications to the afore-mentioned components. That's seems like a lot of expense for a little "marketing hype". I don't have a problem with normal gear whine.
I was just wondering why one manufacturer makes a point of extolling the virtues of helical cut gears while the next does the same for straight cut gears. I guess it's like anything else.
#20
09-09-2010, 07:38 PM
"Marketing hype"? I don't think so. The MoCo had to go to helical gears in response to customer whine about gear whine. Helical cut gears impart a lateral thrust to each other which will put additional stress on the shaft bearings and cases, which will require design modifications to the afore-mentioned components. That's seems like a lot of expense for a little "marketing hype". I don't have a problem with normal gear whine.
I was just wondering why one manufacturer makes a point of extolling the virtues of helical cut gears while the next does the same for straight cut gears. I guess it's like anything else.