Ironhead Suspension Mods
#1
04-14-2009, 02:33 PM
Ironhead Suspension Mods
I posted this in another forum, but I think it really belongs here, so.....
Well, I'm finally happy with the suspension on my bike. It handled OK before, but the stock rear shocks were worn out, and weren't that great even when new. I decided to go in a mild cafe' direction with the old XLX. I picked up a pair of FXDX rear shocks last year, and while they are quality units, the bike handled worse after installing them. They are 3/4" longer than the 12.5" stockers, and that extra weight bias on the front end brought to light how sacked-out the front springs were. I installed a SE fork brace, but the bike wallowed pretty bad when cooking through any corners that weren't smooth.
Next step was to buy new front springs. I bought a pair of Progressive springs and put them in Saturday. I was unsure of the proper preload for these springs, so I installed them with no spacer, for a preload of about 3/4". Put in Bel-Ray 15wt fork oil, 5.5" from the top of the tube with the front end collapsed (before I put the springs in). Put it all back together and went for a ride.
Still wallowing somewhat, too much sag (not enough preload) in the front, and the rear shocks aren't damping enough, creating a pogo effect. Went back home, pulled the caps again, and put a 3/4" PVC spacer in each tube, which left the front sag at about 1/2" unladen, and about 1.5" with me sitting on the bike. Then I played with the damping adjustment on the rear shocks to slow the rebound, and settled on click 8 out of 10, with the springs on the lowest preload, for a rear sag of about an inch with me on board.
Went for another ride, and WOW! Like night and day - the old Sportster corners like it's on rails. No wallow, no pogo, no headshake. The suspension is very controlled and the bumps are absorbed with no undue chassis movement. Much less front-end dive when grabbing a handfull of front brakes, too. Rode some pretty twisty stuff and some rough roads I used to avoid, and I'm happy. It's still just an old Ironhead with 35mm forks, but I think it's about the best performance I can get out of the stock front end and frame. Posted this as info for anyone else looking to upgrade the suspension on an older bike. Here's a pic I took while measuring the fork oil level with the front suspension compressed - I thought it looked cool, sort of like a drag racer.
Well, I'm finally happy with the suspension on my bike. It handled OK before, but the stock rear shocks were worn out, and weren't that great even when new. I decided to go in a mild cafe' direction with the old XLX. I picked up a pair of FXDX rear shocks last year, and while they are quality units, the bike handled worse after installing them. They are 3/4" longer than the 12.5" stockers, and that extra weight bias on the front end brought to light how sacked-out the front springs were. I installed a SE fork brace, but the bike wallowed pretty bad when cooking through any corners that weren't smooth.
Next step was to buy new front springs. I bought a pair of Progressive springs and put them in Saturday. I was unsure of the proper preload for these springs, so I installed them with no spacer, for a preload of about 3/4". Put in Bel-Ray 15wt fork oil, 5.5" from the top of the tube with the front end collapsed (before I put the springs in). Put it all back together and went for a ride.
Still wallowing somewhat, too much sag (not enough preload) in the front, and the rear shocks aren't damping enough, creating a pogo effect. Went back home, pulled the caps again, and put a 3/4" PVC spacer in each tube, which left the front sag at about 1/2" unladen, and about 1.5" with me sitting on the bike. Then I played with the damping adjustment on the rear shocks to slow the rebound, and settled on click 8 out of 10, with the springs on the lowest preload, for a rear sag of about an inch with me on board.
Went for another ride, and WOW! Like night and day - the old Sportster corners like it's on rails. No wallow, no pogo, no headshake. The suspension is very controlled and the bumps are absorbed with no undue chassis movement. Much less front-end dive when grabbing a handfull of front brakes, too. Rode some pretty twisty stuff and some rough roads I used to avoid, and I'm happy. It's still just an old Ironhead with 35mm forks, but I think it's about the best performance I can get out of the stock front end and frame. Posted this as info for anyone else looking to upgrade the suspension on an older bike. Here's a pic I took while measuring the fork oil level with the front suspension compressed - I thought it looked cool, sort of like a drag racer.
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