Front sprocket change
Seasoned HDF Member
Joined: Mar 2012
Posts: 100,455
Likes: 19,811
From: Centennial, CO
Thanks, bikerlaw. Contemplating this swap for this winter. Have a set of heads to do first though. Did the belt have to be replaced for a longer model? I imagine R&R of the swingarm bushings etc. would be in order since it is all apart anyway.
Ultimate HDF Member
Joined: Jun 2007
Posts: 9,193
Likes: 494
From: Richmond, VA
I bought the Fat Boy with just over two thousand miles on it, so it needed no additional parts. The pulley moved the axle 20-25% of the available adjustable distance, forward. So for me, the axle went from about 3/4 to the rear, to about dead center in the swingarm. No belt needed.
Last edited by bikerlaw; Nov 28, 2013 at 03:27 PM.
Stellar HDF Member
Joined: Dec 2005
Posts: 3,302
Likes: 274
From: Milton, Delaware
Stellar HDF Member
Joined: Dec 2005
Posts: 3,302
Likes: 274
From: Milton, Delaware
Okay, question for you gear gurus.
The spec sheet that I have for my 06 Deuce says:
Primary Drive Chain 36/25
Do those numbers refer to the number of sprocket teeth?
If so, why does the Andrews chart show;
5 speed 94-06 (except 95 Softail) stock 32 front 70 rear.
This thread seems to refer to a 32 tooth front sprocket.
What am I missing?
The spec sheet that I have for my 06 Deuce says:
Primary Drive Chain 36/25
Do those numbers refer to the number of sprocket teeth?
If so, why does the Andrews chart show;
5 speed 94-06 (except 95 Softail) stock 32 front 70 rear.
This thread seems to refer to a 32 tooth front sprocket.
What am I missing?
Ultimate HDF Member
Joined: Jun 2007
Posts: 9,193
Likes: 494
From: Richmond, VA
Okay, question for you gear gurus.
The spec sheet that I have for my 06 Deuce says:
Primary Drive Chain 36/25
Do those numbers refer to the number of sprocket teeth?
If so, why does the Andrews chart show;
5 speed 94-06 (except 95 Softail) stock 32 front 70 rear.
This thread seems to refer to a 32 tooth front sprocket.
What am I missing?
The spec sheet that I have for my 06 Deuce says:
Primary Drive Chain 36/25
Do those numbers refer to the number of sprocket teeth?
If so, why does the Andrews chart show;
5 speed 94-06 (except 95 Softail) stock 32 front 70 rear.
This thread seems to refer to a 32 tooth front sprocket.
What am I missing?
Road Warrior
Joined: Dec 2011
Posts: 1,805
Likes: 47
From: Lake Tahoe California
If we could find a 68 tooth pulley for the rear that fit, it would accomplish essentially the same gearing as the 34 front pulley swap with much less difficulty. Wish the sportster 68 tooth pulley fit. Custom rear pulleys cost $3-400. The only other rear pulley that is a direct swap is the 66 tooth unit and that requires a belt change, which makes it just as hard as the front pulley swap. So why bother with that route? I figure if going with the front pulley swap route, might as well replace the belt. Ideas?
Cruiser
Joined: Jun 2010
Posts: 136
Likes: 0
From: Oak Harbor
I read that each tooth on the front pulley is comparable to 2 teeth on the rear pulley so if that's the case the 66 tooth rear pulley might give close to the same ratio as a 34 tooth front pulley. Sure would be easier to change the rear pulley, but there goes the protection of the stock belt guard.
If we could find a 68 tooth pulley for the rear that fit, it would accomplish essentially the same gearing as the 34 front pulley swap with much less difficulty. Wish the sportster 68 tooth pulley fit. Custom rear pulleys cost $3-400. The only other rear pulley that is a direct swap is the 66 tooth unit and that requires a belt change, which makes it just as hard as the front pulley swap. So why bother with that route? I figure if going with the front pulley swap route, might as well replace the belt. Ideas?
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Cruiser
Joined: Jun 2010
Posts: 136
Likes: 0
From: Oak Harbor
I recently sold the bike, so I can't remember what 60 was. QC, I did nothing. You can have the dealer recalibrate the speedo, but I didn't bother. Based on my GPS and extensive monkey testing, I can say that the speedo went from running a stock 2mph fast to 2mph slow. Meaning stock, actual 70 read 72 on the speedo. With the 34 tooth, 70 read 68.
Pretty close to what I found yesterday using my GPS too, but I only checked it at 60mph. With the 34 tooth front pulley I'm now doing 62 when the speedo reads 60.
Last edited by Greabert; Nov 29, 2013 at 10:11 AM.
Stellar HDF Member
Joined: Dec 2005
Posts: 3,302
Likes: 274
From: Milton, Delaware
36/25 is the number of teeth in the bikes primary. 32/70 is the number of teeth in the rear drive belt setup. i.e. the pulleys that spin the back wheel. When we refer the going from 32 to 34, we are swapping the pulley that spins the final rubber drive belt to the rear tire. The 32 tooth pulley is attached to the transmission. The pulley on the rear wheel itself is the 70 in question. (on most bikes)
