Washers vs. PCV Pipe for fork preload
Road Warrior
Joined: Feb 2007
Posts: 1,625
Likes: 349
From: The Biggest Little City, Reno, NV
You can use washers, the reason for pcv pipe is the spacer is normally long enough that it would take alot of washers. The pcv is easy to cut and cheap.
What I did was used pcv for my spacer, I cut it 1/2 inch shorter, and just installed preload adjusters.
What I did was used pcv for my spacer, I cut it 1/2 inch shorter, and just installed preload adjusters.
Last edited by whylee; Jul 18, 2020 at 10:31 AM.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
You apparently haven't done this before! Exactly what are you doing? If you want to make fine adjustments say to stock Harley fork springs, then you may be right. However if you are using aftermarket springs they are normally a lot shorter than stock springs and the spacers you need will be quite long. Buy a length of thick-walled upvc plastic water pipe and a cheap hand pipe-cutter from a DIY store. You have enough pipe to make spacers for several bikes and it takes just a few moments to cut each fresh length, with neat square ends.
Grand HDF Member
Joined: Nov 2018
Posts: 4,607
Likes: 3,312
From: Virginia
You are going to be doing adjustments by 1/4", (according to the instructions in my progressive spring box). I can't see any Harley being sensitive enough in the suspension to need the thickness of a washer to tell the difference in the front suspension. Also that spacer sits up above the top of the fork tube and is pushed down in compressing the spring (at least it was on my 2006). A stack of washers would be almost impossible to have kept lined up while pushing down against the force of the spring.
Progressive has been doing this a long time, they sent a piece of PVC pipe with my springs.
Progressive has been doing this a long time, they sent a piece of PVC pipe with my springs.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
That is the case with all aftermarket spring brands in my experience, over many years. Simply put they make springs to suit all brands of bikes, whereas a vehicle manufacturer such as H-D makes their springs to match their own specific applications. Plastic water tube is the way to go, but also buy a cheap pipe cutter, don't attempt to hacksaw pipe by hand, as the end will seldom be square. Turning them in a lathe would be a good alternative!
Grand HDF Member
Joined: Nov 2018
Posts: 4,607
Likes: 3,312
From: Virginia
To answer you second question.
The washers shouldn't be moving they are pushed firmly up, so I can't see how shavings or wear would be a problem. Even with PVC pipe you put a washer at the top of the spring between the spring and the PVC pipe. and if wear was a problem PVC pipe would wear more than a metal washer.
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Schedule 80 (dark grey stuff) PCV pipe works great. Lot of people use washers on the bottom between the PCV and the spring to help it seat better. But if you're planning on regularly making changes, washers could be decent. It all depends what you need the spacer to do, either washer or PCV works fine.
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Grand HDF Member
Joined: Aug 2018
Posts: 4,126
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From: W. MI.
You apparently haven't done this before! Exactly what are you doing? If you want to make fine adjustments say to stock Harley fork springs, then you may be right. However if you are using aftermarket springs they are normally a lot shorter than stock springs and the spacers you need will be quite long. Buy a length of thick-walled upvc plastic water pipe and a cheap hand pipe-cutter from a DIY store. You have enough pipe to make spacers for several bikes and it takes just a few moments to cut each fresh length, with neat square ends.
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Stellar HDF Member
Joined: May 2007
Posts: 3,258
Likes: 522
From: USA
Thank you all.
FWIW I have the Progressive Susp. springs, which are a +1 mod, installed with their supplied PCV spacer.
I did not have any PCV at home, but had metal washers.
One issue is the length of the spacer and the strength needed to reinstall the fork tube caps.
1/2 inch increase maybe my limit.
My recollection is my washer modification totaled a 7mm increase, yet for my weight and sag I could use more.
FWIW I also increased the oil level slightly with Harley Performance Fork Oil added on top of the standard OEM spec Harley Fork Oil (have to check my notes for how much, but not very much) and I have the a fork oil level tool.
Fork function/action works well for me, yet I asked as the sag is just not correct.
Again thank you all.
FWIW I have the Progressive Susp. springs, which are a +1 mod, installed with their supplied PCV spacer.
I did not have any PCV at home, but had metal washers.
One issue is the length of the spacer and the strength needed to reinstall the fork tube caps.
1/2 inch increase maybe my limit.
My recollection is my washer modification totaled a 7mm increase, yet for my weight and sag I could use more.
FWIW I also increased the oil level slightly with Harley Performance Fork Oil added on top of the standard OEM spec Harley Fork Oil (have to check my notes for how much, but not very much) and I have the a fork oil level tool.
Fork function/action works well for me, yet I asked as the sag is just not correct.
Again thank you all.