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Apr 25, 2022 | 07:38 PM

#21

MarlinSpike

Stellar HDF Member

Joined: Sep 2021

Posts: 2,024

Likes: 1,472

From: Black Hills of SD

Quote:

Originally Posted by gerald martin

The reason is that the speed limits here are almost all 55 mph. When I am in fourth gear at 55 mph it seems to be reving a bit high but when I put it in 5th it seems it might be lugging. I have been told and I dont know if its true that the twin cams like to have their rpms on the high side so I would like to know if I am over reving in 4th or lugging in 5th. I have looked into getting a Speedo with tack but Harley doesn't make one for the 02 fatboy and I want to keep my bike all Harley. I would like to keep my revs just under 3000 so that is why I am asking

When on my 2002 FB I use 5th if I am hitting 50 MPH or more. I would rather lug it than rev it. The bike seems to like it better.
Totally get the whole "All Harley" comment - me too.

Apr 25, 2022 | 07:43 PM

#22

brakeless

Seasoned HDF Member

Joined: May 2017

Posts: 5,915

Likes: 5,929

From: NorCal

Yeah sometimes I find myself in 5th at 45mph just not paying attention or being tired. That's just over 2000 rpm. Which is lugging it. You shouldn't be under 2000 rpm in any gear other than 1st. But like I said my bike at 55 in 4th is under 3000rpm.

Apr 25, 2022 | 07:54 PM

#23

hattitude

Seasoned HDF Member

Joined: Sep 2008

Posts: 14,148

Likes: 11,222

From: San Diego, CA

Lugging the engine is not just RPM....

It's the combo of RPM and load....

Given the same gear, just because you are at a lower RPM, doesn't mean you are lugging it... and just because you are at a higher rpm, doesn't mean you aren't lugging it...

Going 2500 rpm in 5th gear on a flat road (or slight downhill grade), could be totally appropriate...

Going 3000 rpm in 5th gear, two-up with touring gear, on a steep hill can be lugging it....

Learn to listen to your engine, it will tell you if you are lugging it, then just downshift....

I currently have two bikes with no tach, I really don't feel I need one, and so I don't give RPM a second thought when riding those bikes... I just listen to the engine and downshift/upshift... On the bike with the tach, I'll note my RPMs from time to time, but don't use the tach to upshift or downshift... I shift based on the sound of the engine...

FWIW... A well tuned and maintained Twin Cam can cruise at 3500RPMs all day long..... I know this for a fact...

Last edited by hattitude; Apr 25, 2022 at 07:59 PM.

Apr 25, 2022 | 08:49 PM

#24

brakeless

Seasoned HDF Member

Joined: May 2017

Posts: 5,915

Likes: 5,929

From: NorCal

Quote:

Originally Posted by hattitude

Excellent explanation hattitude!

Apr 26, 2022 | 05:48 PM

#25

byersmtrco

Supporter

Joined: Sep 2006

Posts: 3,714

Likes: 650

From: San Ramon, Ca

Quote:

Originally Posted by Cap77

He's asking RPM @ 55 mph in "fourth" gear, Guys

best i can help, Ger (which may be no help at all)
My '04 Deuce (5sp trans/stock TC88) would be around 2900 or so @55mph in fourth gear

..L.T.A.

That would be very close.

I usually shift into 5th around 60 mph

Last edited by byersmtrco; Apr 26, 2022 at 05:52 PM. Reason: added

Apr 26, 2022 | 08:55 PM

#26

98hotrodfatboy

Seasoned HDF Member

Joined: Mar 2010

Posts: 21,104

Likes: 7,632

From: Poolville

My calculator puts it at 2700 rpm@55....
25/36-32/65 with tire circumference of 79.21"
2.94
2.21
1.60
1.23
1.0

Last edited by 98hotrodfatboy; Apr 26, 2022 at 09:01 PM.

Apr 27, 2022 | 05:29 AM

#27

Madison Bill

Road Warrior

Joined: Oct 2014

Posts: 1,610

Likes: 1,134

From: Southconsin

Quote:

Originally Posted by gerald martin

Just asked a simple question. I dont want a tach as I want my bike completely stock. If you dont know the answer to my question why even comment.

This Harley forum is one of the best on the internet and I am sure most here would agree. As proof, a person with your attitude still had good people willing to help.
Oh, I almost forgot here is my completely stock oil bag.