Besides Rev-Tech, RedLine makes a 20W60 for use in the air cooled V-twin. I'm running it in my bike, can't say that it makes things any quieter though. This winter I'll switch to the 20W50.

 

If you re-read your manual, it says 20w-50 is acceptable AND at that temp you can opt for 60. If you look at the chart, you will see that all temp ranges are covered by 10-40 and 20-50 with 50 being optional when temp is always 60F I believe and 60 being optional at a constant 80F i believe.

Re-read it - you'll see you can have 20-50 in it right now. Oh yeah, H-D specifically states not to use additives last time i checked.

 

I have an 81 Shovel head Wide Glide. The manual recommends 50 weight. The HD service recommends 20/50. My personal mechanic recommends straight 50 or 60. Any suggestions as to what is best?

 

For a Shovel Head, Summer, I would go with 60 weight.

 

I switched from RevTech 20w50 (made a lot of racket) to HD-60W and my bike is a lot quieter.
Of course where I live it is hot at 10am.
Next I'm going to run Shaffer's 25w60 year round since I found some locally.
I change my oil about every 2k so it doesn't make since to me to use synthetic oil.

Just a thought, but haven't had a problem w/straight 60w.

37k on the dial.