Forks Compressed - Help

[TCalYen]

I am going to change my fork oil…

However I just noticed that my front fender is sitting only 3 or 4 inches above my front tire. What the heck? I’be never messed with forks of any kind.

Before I start I’d like to have everything I need to get the forks fixed.

Can anyone help with a possible reason the forks are compressed so much and what I will need to fix?

Thank you as always…

[Bruces]

What bike do you have ? Is this a new bike that you are just setting up ?

[Megadan]

Originally Posted by TCalYen

I am going to change my fork oil…

However I just noticed that my front fender is sitting only 3 or 4 inches above my front tire. What the heck? I’be never messed with forks of any kind.

Before I start I’d like to have everything I need to get the forks fixed.

Can anyone help with a possible reason the forks are compressed so much and what I will need to fix?

Thank you as always…

It's called rider sag, and it's directly related to your own weight and the bike weight against the spring rate, spring preload, and the fluid air gap in the fork tubes.

The easiest way to set it is to adjust the preload by making spacers for the springs in the fork tubes. The longer the spacer, the more preload, the less sag under load.

The ideal way would be to do the math to figure out what the ideal spring rate for the bike with you on board, and then put in a spring of the appropriate weight, and then adjust the preload to dial in the sag. You could still do this, but finding an off the shelf spring is pretty difficult. There are companies that will make fork springs to your spec out there though, if you really want to go down that path.

The fluid air gap is something that can also be adjusted to compensate for weight and ride quality. Basically, the air in the fork tube once closed is trapped in a sealed container. As the fork compresses the volume of the air decreases and the air pressurizes. This actually acts as a secondary spring with a progressive spring rate. This is why some of us run 200-230ml of fork oil in our standard Hawk forks.

If you have USD forks I won't be much help in figuring out preload and setup, but if you have standard forks I can likely get you dialed in pretty close.

[TCalYen]

Sorry about that. It’s a 2016 hawk with only 150 miles on it. I’ve barely ridden the thing. I do weigh about 240 lbs. can the forks depressurize? I have no other explanation for them to be this way other than the bike was sitting for years. A buddy of mine put the front end together but if I remember correctly the forks were already installed when the bike arrived in the crate.

I’m fine with rigging some spacers up. I will only be riding the Hawk on the street.

What length do you all suggest with me at 240 lbs?

[Megadan]

Originally Posted by TCalYen

Sorry about that. It’s a 2016 hawk with only 150 miles on it. I’ve barely ridden the thing. I do weigh about 240 lbs. can the forks depressurize? I have no other explanation for them to be this way other than the bike was sitting for years. A buddy of mine put the front end together but if I remember correctly the forks were already installed when the bike arrived in the crate.

I’m fine with rigging some spacers up. I will only be riding the Hawk on the street.

What length do you all suggest with me at 240 lbs?

I would say at least 40-45mm (1 3/4inch) length spacers would be a good place to start.

If those forks haven't had any sort of service done in a while I would say to drain the fork oil out and put fresh stuff in. I always liked how my Hawk rode with about 200ml of fluid in it.

[RogueBull]

What type of oil are you using
in the Hawk? I will be getting my delivery hopefully in the next couple weeks and read that I should change it out from the start? Any thoughts?