Yikes! 290*F?
If you get an oil cooler, would you go with a DK Custom set up, or something else?

 

Unknown.
I had a small radiator-type oil cooler on my old Triumph years ago. I couldn't get an accurate temp reading though, so it was installed out of concern and worry.

I've seen several versions of oil coolers for the V-Twin, some more effective than aesthetically pleasing, and some that look better than they perform.

I haven't seen one that I believe would reliably keep oil temps under 250°-260°, which I think is the "sweet spot".
I'll need to do some homework if I decide to get one.

 

The OP gauge will be 100% more useful that the air temp gauge that only tells you how warm it is inside the fairing.
Buy the oil temp gauge if you feel you need to know what the temp is in the pan, otherwise when your nards are sweating you will know that the engine is getting hot.
Rob

 

I installed one on my 07, mainly because I found a new one on eBay for $50. I put it in during a maintenance job and also while I had the front fairing off. Pretty simple job.

With that said, I’ve seen it hit 250 on a couple occasions this summer while in some SoCal stop and go traffic. Tells me I probably need a fan-assisted oil cooler from one of the major aftermarket players to keep the oil temps as low as possible.

Also, FWIW in 100+ temps and cruising at 85 I’m consistently at 230ish.

 

While I agree with RollaMo, I kind of like gauges and would like to know what the temp is.

I moved the stock cooler on my ‘16 RG to the inside of the left side engine guard, out into the wind. 2 hours into a ride one day I was going down the freeway and put my bare hand behind the cooler and felt no heat coming through.

I could put a little ducting in front to force air through and visually suffer but I have some coolers off an Aprilia and thought about how I could add one of those instead, again without it looking too cobbled on.