• Welcome to the Two Wheeled Texans community! Feel free to hang out and lurk as long as you like. However, we would like to encourage you to register so that you can join the community and use the numerous features on the site. After registering, don't forget to post up an introduction!

Fork Oil Weight

Joined
Aug 24, 2010
Messages
177
Reaction score
36
Location
WARDA, TEXAS
First Name
Hollidayjay
Converted the Honda VTX1800f to Trike, and it seems like it gained a couple hundred pounds. Does anyone out there have experience with using different weight fork oils ? Any recommendations based on experience would be greatly appreciated.
 
On a particular bike, the fork oil weight should be matched to the spring rate. Adding weight may cause you to swap fork springs, and then you need to adjust the fork oil. Of course to some extent you can adjust it for preference, feel or for road surface.

Tldr, you probably don't need to change it if you didn't change springs and don't have complaints about handling.
 
With an open chamber fork and added weight 20 or 30 would be a good start.
 
Be careful changing weights. A small bump up can make a huge difference. I went from 5w to 10w once and it sucked. The heavier weight made the front end feel like a rock. I had to go back to 5w. Just fresh oil now and then can be the correct fix.
 
Trial and error. Take small steps. I had read blending two different weight fork oils is linear so equal parts 5W and 10W gives 7.5W.

You may also want to consider adding pre-load with longer spacers if the ride height was affected.
 
Are the VTX1800 forks the same as the GL1800 Goldwing?

If so, I put heavier springs in my GL1800 and went to a 20 wt so the fork could damp the big spring. Stock oil is really thin,.like 5-7wt.

If you leave stock springs, I wouldn't go much above 10 wt. If you go with stiffer springs do a 15 or 20 wt.

I have 1.2 kg/mm springs in mine with the 20 wt and the ADV valve disabled. For reference, the stock springs on the Goldwing are about 0.8 kg/mm so my springs are about 50% stiffer than stock.
 
Back
Top