# What is a preload adjuster? a speed lockout?



## RAKman (Nov 23, 2010)

I'm a newbie here, and to mtb'ing. I've got a new bike with a suspension fork featuring a preload adjuster and a speed lockout. I downloaded the fork manual from Suntour, but this document offers no explanation. Maybe you can.

Thank you.


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## ProjectDan35 (Jul 19, 2010)

Preload will adjust how stiff the fork is. More plush ( soft), or hard to compress. lockout will LOCK the fork out, as a rigid fork ( no suspension) would be like. Which makes it a no front suspension bike. It's handy for riding on the road because when pumping hard a lot of the power your using to go forward is being absorbed by the fork compressing. This prevents that.


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## RAKman (Nov 23, 2010)

Hi, Dan, and thank you for taking the time to reply. 

I've got the general idea of how the fork works, but I'm wondering what it is that's "loaded"? Loaded before what? And why do I want to "lock out" speed? It's sounds like a kind of brake.


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## AndrwSwitch (Nov 8, 2007)

Preload prevents the fork from compressing unless it sustains a biggish hit. You may have noticed your bike bobs a little bit when you're riding on a smooth surface, especially if you pedal particularly hard - it's to prevent that. Most forks with a lockout will still be able to compress a little bit. You'd choose to do it because it's disconcerting and some of the energy you use to compress the fork instead of driving the bike forward is wasted. When the fork is locked out, all that energy goes toward moving the bike. There have been reports of problems using the lockout on Suntour forks, so I'd leave it open unless I was on the road.

Preload is a mechanical device that compresses the spring. It's loading the spring before you do. If you feel like getting into the mechanics of it, look up "Hooke's Law" and spend some time looking at exploded diagrams - I always find it interesting to know how things work. As far as how to use it, the effect of preloading a fork is that it will sag less when you sit on the bike. Bikes handle best with a certain amount of sag, and suspension forks work better if they sag a little bit, so that the fork can extend a little when the ground drops away from under it, but have most of their travel available for the obstacles you'll run over.

Riders of different weights typically use different springs in coil forks. Unfortunately, they're not available for Suntour forks, so if the spring you have is wrong for you, you have to live with it or buy a new fork.


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## RAKman (Nov 23, 2010)

Hi, Andrw, and thanks for taking the time to explain. I'll be sure to look into Hooke's Law. I also like learning how things work. As you might have gathered, I'm also interested in linguistics. So I guess what's happening with the suspension is that the rider is adding, or loading, tension. But why not just call it a loader? Why "pre"-loader? Prior to what? And the speed lock-out? Isn't the rider really locking out drag, not speed?

Nice blog, btw.


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## AndrwSwitch (Nov 8, 2007)

Whoops. I totally mistyped. In the first paragraph, I meant to say "lockout prevents..."

I'm not sure why it's called a "speed lockout" unless they're saying that it works faster than a previous model.


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## zebrahum (Jun 29, 2005)

It's called preload because you set it before you weight the bike. It's a setup activity and you do it probably once just to make sure the suspension is working properly. So when you buy a new bike, you set up the preload to fit your body weight then you leave it alone. Load is what you do when your body and the forces from the terrain compress the spring in the fork.

As for the speed lockout, I think it's just marketing talk. It's a lockout for your fork, I think it implies that it's fast at locking out the fork. Either way, there's nothing unusual about it as far as I can tell; it's just a lockout.


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## TheYoungBikeGuy (Oct 19, 2011)

I think its called speed lockout because you can lockout while your riding or you dont need tools and so you just push a button... i think thats what i heard.


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## ValhallaGSXR (Apr 3, 2010)

That post is a year old, i think he figured it out by now.


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## miseryguts (Apr 12, 2021)

ValhallaGSXR said:


> That post is a year old, i think he figured it out by now.


It's ten and a half years old now.
I'm a different person but I'm still reading it and I'm glad he took the time to come back and clarify.


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