​​​​​​ Because VR1 it's made for higher compression engines with more zinc to protect the cylinder wear better, especially in our air cooled motors..I was never sold on Synthetics...

 

Oh well

 

Just my two cents . This time last year (2021), I had my 2014 Ultra rebuilt.(Andrews 48's, new pistons, heads rebuilt and then dyno tuned). Both the engine builder and dyno tuner (also a engine builder ) were adamant about using Valvolin VR1 20w50 in the engine. They were both dead set against synthetics. I didn't get into the discussion. Between the two of them, they see what is going on inside the engines, so I take their word.. Again just my two cents and my experience.

 

No Syn for me......I prefer Dino Bel Rey or Maxima 20W-50 V-Twin oil as I have found my top end to be quitter. I've ran Amsoil, Mobil 1, Redline, all in the past and I seemed to get more top end chatter with the syns. After a rebuild I used Dino for the breakin and liked how quite it was and didn't notice any extra heat. So I said what the hell and made the switch. I change my oil at 3k mile religiously and have found no additional wear or heat using Dino. It's not about money saving for me at all so the fact i am saving money is a plus. Your results may vary but it's just what I have found that works for me.

 

Are you sure??? LOL

 

I ran Mobil synthetic in my 2011 twinkie for the first 40k miles and then switched to dino , it hasn.t imploded yet...

 

I gave up on the Synthetic Kool-Aid. Motors been running on Dyno for a long time. And will keep on keepin on.

 

Can anyone provide some factual data showing failures or excessive wear in HD engines attributable to conventional oil? Or, less wear or failures provided by synthetic oil?

I won't hold my breath.

 

I'm sure an amsoil dealer could come up with something. I'm amazed none chimed in here to advise to run their snake oil.

 

That "snake oil" has been in Reaper's engine since her first oil change. After 18 seasons, and over 350,000 kms (217,500 miles), the cases will be split, for the first time, this winter. For the last 17 of those seasons the bottom end has been under a 98 ci @10.5:1 top end that puts out ~100 hp/~120 ft-lbs at the rear wheel. I can't say that's solely due to running Amsoil, but I do credit it for contributing to the long life of the original bottom end. While I am consistent with oil change intervals, there have been a number of occasions where I have had to double the intervals.

Anyway, to answer the OP, no, it isn't necessary, but I personally do recommend it. Whatever your favourite brand may be. Just make sure it's true full synthetic.

Cheers!