What oil to use in Harley-Davidson primary drives

“Hi, I have been using your Mobil 1 MX4T (Mobil 1 Racing™ 4T 10W-40) for 4 years and love it in my Japanese motorcycles. I have purchased a '08 Harley and want to continue to use Mobil 1™ motor oil but use 20W-50 in the engine. What do you recommend I use in the transmission and the primary drive? I have no problem using Mobil 1™ Synthetic Gear Lube LS 75W-90 in the transmission, but what do you recommend for the primary drive? Any other information related to this would be greatly appreciated. Thanks for your assistance.”

Gregg Gillette, Charlotte, North Carolina


You actually have a couple of choices for the primary drive. The optimum product would be Mobil 1 Racing™ 4T 10W-40 motorcycle oil, but it is also okay to use Mobil 1™ V-Twin 20W-50.

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