Kinda narrows it down for me......below 90-95 I don't need it.......When it's over 105 is when I want everything I can get to cool the bike (and me) off.......

YMMV

Lon

 

The fan doesn't push air. It sucks air and blows it below the bike. It will not help "cool" the rear cylinder. The coolflow fan is purely a comfort item not a performance item.

 

I had the cool flow fan installed by the dealer and they only charged me 1 hr. It's a 2.5 hrs job so I was treated very well.
The fan is worth it.
I'm going to make the argument that the fans cools both the passanger and the rear cylinder.
Consider the orientation of the fan,it is facing towards the rear cylinder. Remember we are talking slow speed.
This fan is drawing air in. Where is this air coming from?
Because of the fans close proximity to the rear cylinder, air has no choice but the be drawn across the fins of the rear cylinder, into the fan and under the rear fender well.

 

I agree!!

 

in theory, perhaps, evacuating heat more effectively makes sense..but in reality if you tested the cylinder heat (heat gun, engine temp sensor, whatever) with the fan on and off under identical circumstances/conditions guess I'd be surprised if there was much difference...bottom line is it does sound like it effectively improves rider/passenger felt heat so accomplishes its main objective

 

I agree too. Hot day, stop and go traffic in town, that's when you need air flow. I don't think it would be a big difference but, as we all know, any air flow is going to help in slow traffic , just simple common sense.

 

I've had mine for the last 1000 miles or so on my 2017 Freewheeler. Over that time we've been having a string of 100F+ temps. So far I'm lovin' it for the noticeably less heat felt coming up from the engine. I'm also using "Parade Mode" when the temps top 90F.

Ace Cafe Rat

 

Just make the coolflow work on the HD 2011 Street Glide with the simple switch.
https://www.facebook.com/trung.d.nguyen.33/posts/10154985978148049

 

In theory it makes sense, but you are pulling HOT air across a HOT cooling fin. The airflow (circulation of air) only causes things to "feel" cooler, it does not actual translate to reducing heat (this is specifically in regards to hot air in a hot environment, obviously if you circulate cool air in a hot environment, it will in fact cool things). There is also a lot of open real estate on either side of the fan/cylinder to pull air from, and while the majority of air come from the cylinder, there is much more volume available from the open sides. Hot air is also moves more difficult to move because of the difference in density, and density's effect on viscosity of fluids (yes, air is fluid).

In my mind, I think of the fan as more of a heat containment device - it is pulling hot air, but not very rapidly, and this keeps the air contained within the general area of the cylinder and not rising up/out onto a leg/crotch. Hot air rises due to differences in density, so the fan is trying to overcome that innate tendency, which will slow airflow at the inlet.

Source: 5 different textbooks from my studies in mechanical engineering covering Fluid Dynamics, Thermodynamics, and Heat Transfer.

 

that's deep...I was just thinking this whole topic was 'full of hot air' until now! lol