Belt tension question
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Ultimate HDF Member
Joined: May 2008
Posts: 7,439
Likes: 884
From: 'Noke, VA
Belt tension question
Got a puzzler. Last month I had the wheels on my 2010 FLHTK replaced under warranty by a dealer (stockers were replaced with Agitators). I'm assuming that the belt tension was adjusted when the rear wheel was replaced, but who knows? Two weeks ago, I replaced a pair of 13" Ricor shocks with a pair of 14" Ohlins #3-4s. I checked my belt tension on Monday for my 30k service, and had over an inch of play. I re-adjusted it to 7/16" and thought I was done with it.
I did some reading on belt tension, and realized I may have screwed up. Here's what I did:
-Bike was still warm.
-Bike was on the sidestand.
-I only checked one place on the belt.
-I used the H-D gauge and placed it directly under the window in the belt guard where the hashmarks are.
-I couldn't find my second axle wrench, so I held the weld nut with a pair of channel-locks as I re-tightened everything.
-I took a short (4 mile) test ride.
Realizing that my methodology was suspect, I went out tonight and measured belt tension the same way with the bike cold. 3/4" of deflection. Then for giggles, I measured it again with the rear tire off the ground....Over an inch. Free sag on the shocks is right around 12mm, I have 26mm of rider sag, and 51mm left of compression stroke.
I'm guessing that I still need to tighten the belt, but I'm questioning what spec I should tighten it to. The shop manual calls for 3/8"-7/16" at ambient temperature either on the sidestand or with the wheel off the ground. Problem is that I'm getting over a 1/4" of deflection difference between the two methods. What concerns me is that if the tension increases linearly with suspension compression, at 3/8" deflection with the suspension unloaded, I'm either going to snap the belt or destroy the bearings in the primary once the suspension compresses.
Thoughts?
I did some reading on belt tension, and realized I may have screwed up. Here's what I did:
-Bike was still warm.
-Bike was on the sidestand.
-I only checked one place on the belt.
-I used the H-D gauge and placed it directly under the window in the belt guard where the hashmarks are.
-I couldn't find my second axle wrench, so I held the weld nut with a pair of channel-locks as I re-tightened everything.
-I took a short (4 mile) test ride.
Realizing that my methodology was suspect, I went out tonight and measured belt tension the same way with the bike cold. 3/4" of deflection. Then for giggles, I measured it again with the rear tire off the ground....Over an inch. Free sag on the shocks is right around 12mm, I have 26mm of rider sag, and 51mm left of compression stroke.
I'm guessing that I still need to tighten the belt, but I'm questioning what spec I should tighten it to. The shop manual calls for 3/8"-7/16" at ambient temperature either on the sidestand or with the wheel off the ground. Problem is that I'm getting over a 1/4" of deflection difference between the two methods. What concerns me is that if the tension increases linearly with suspension compression, at 3/8" deflection with the suspension unloaded, I'm either going to snap the belt or destroy the bearings in the primary once the suspension compresses.
Thoughts?
Road Captain
Joined: May 2011
Posts: 545
Likes: 5
From: California
I am new to Harley. Really new. A week. Even newer to this forum. So I comment knowing that I am not all that versed in Harley Davidson bikes.
I am reading various threads to learn about the bikes and how to maintain my new FLHRC. Trying to learn as I read. Your question is one I am curious about. As I can remember adjusting a steel chain at various times because of the stretching that a chain does.
I was reading my FLHRC owner's manual and, as you said, the deflection should be checked at a couple of locations around the drive belt. Then using the largest deflection as your place of reference. This would tell me that you might get varied measurements depending on where you measure.
There is also a comment that when checking the deflection you need to make sure you are using 10 pounds of pressure. Using varied pressure would, I would think, give you varied readings.
So I ask, does the HD tool you are using show the 10 pounds of pressure. I ask because I am wondering if, when I decide to do what you are doing, if I would get various readings based on the pressure I am using to measure the deflection.
I am also wondering if I need the tool you refered to in my effort to take accurate readings.
When you are checking the deflection are you using constant 10 lbs of pressure? Or, is this possible the reason for the various readings?
I am reading various threads to learn about the bikes and how to maintain my new FLHRC. Trying to learn as I read. Your question is one I am curious about. As I can remember adjusting a steel chain at various times because of the stretching that a chain does.
I was reading my FLHRC owner's manual and, as you said, the deflection should be checked at a couple of locations around the drive belt. Then using the largest deflection as your place of reference. This would tell me that you might get varied measurements depending on where you measure.
There is also a comment that when checking the deflection you need to make sure you are using 10 pounds of pressure. Using varied pressure would, I would think, give you varied readings.
So I ask, does the HD tool you are using show the 10 pounds of pressure. I ask because I am wondering if, when I decide to do what you are doing, if I would get various readings based on the pressure I am using to measure the deflection.
I am also wondering if I need the tool you refered to in my effort to take accurate readings.
When you are checking the deflection are you using constant 10 lbs of pressure? Or, is this possible the reason for the various readings?
Last edited by Matt0987; Jun 1, 2011 at 07:49 PM.
Seasoned HDF Member
Joined: Aug 2007
Posts: 39,612
Likes: 2,115
From: Central, Ca.
If you haven't heard of the twist test grab the belt with your thumb and fore finger and twist, if it will twist 45 degrees you're good. Cool bike on stand. I went thru all the adjustment procedures then checked the twist and it was right on 45 degrees, it works.
Account Retired
Joined: Oct 2009
Posts: 3,245
Likes: 12
From: Here
Don't know if this will answer your question, but I've played around with adjusting mine to the manual. I've found the best way to get it as close as possible is adjust it on a lift. I adjust mine on the loose side 7/16 because It will tighten a little when everything heats up. These drive belts are very durable and don't stretch much.
Cruiser
Joined: Jul 2008
Posts: 142
Likes: 0
From: S.W. Iowa
I went through the same thing this past weekend with my wifes bike, put new tiires on and had to readjust the belt, the puzzling thing was the service manual I belive says to do it on the jack with tire hanging and I thought the owners manual says to have somebody sitting on the bike on the ground. I can't belive that you could get same readings between the two methods. I think I did hers with it sitting on the ground. But sure might have to give this twist test a try.
Road Master
Joined: Feb 2005
Posts: 1,109
Likes: 3
From: Chattanooga, TN
You must use the HD belt tension tool to properly adjust the belt to the required 3/8" - 7/16" specs with 10 pounds pressure on the belt using the HD tool. You will also need the HD 36MM tool from the tool kit and a 36MM socket, or two 36MM sockets. You must hold the fixed side (left side) in place while you tighten the right side and torque to 95-105 ft/lbs. Make sure you lube the face of the axle nut. You may have to do this a couple of times before you get it right.
Adjust cold on the side stand with 10 PSI shock pressure.
Adjust cold on the side stand with 10 PSI shock pressure.
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Account Retired
Joined: Oct 2009
Posts: 3,245
Likes: 12
From: Here
You must use the HD belt tension tool to properly adjust the belt to the required 3/8" - 7/16" specs with 10 pounds pressure on the belt using the HD tool. You will also need the HD 36MM tool from the tool kit and a 36MM socket, or two 36MM sockets. You must hold the fixed side (left side) in place while you tighten the right side and torque to 95-105 ft/lbs. Make sure you lube the face of the axle nut. You may have to do this a couple of times before you get it right.
Adjust cold on the side stand with 10 PSI shock pressure.
Adjust cold on the side stand with 10 PSI shock pressure.
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Road Captain
Joined: Jan 2010
Posts: 709
Likes: 2
From: SO Cal
This is funny!!! What has 10 lbs of shock pressure have to do with belt tension???? LOL. I agree with everything except the shock pressure and being on the jiffy stand. The belt can be adjusted properly on a jack. In fact to me it's easier that way. You can adjust and rotate the wheel and check again and again. Works for me!!
