24 March 2012

Set up the suspension for your mountain bike

My MGT mountain bike really is a product of my frugality. (Some would say cheapness.) I bought it at a pawn shop on East Third Street. It had great promise in my eyes, even with the broken cables, rusted chain, and sheared bar-end grips. I was lucky that the bright yellow color didn't raise its price in the appraiser's mind, and that the selling price was only twenty-five bucks.

I took the MGT in to my buddy Brian at Links & Kinks, and he refurbed it for the cost of a thorough tune-up. I was on the trail after spending less than $150.

That was a couple years ago. After buying another bike in Palm Springs and using it on the rocky hills there, I've become more discerning, more demanding of the performance on the trails. I'm still happy with the MGT, even though it's a small frame, so I don't intend to buy into the next level of performance. Instead, I've begun to pay attention to the suspension.

I noticed in one of my first rides this spring that the front forks really didn't have much movement. So I had Brian look at it, and he saw that the forks had seized. Where the forks should compress about 20% when I get on the bike, there was less than 5% change. On the trail, I could sense a bit of response in the forks, but not much.

So I asked Brian to replace the front fork and its suspension. Now the bike is so much more enjoyable. More responsive when I pull up to hop a log. Less of a jolt when the front wheel sets back down after a jump or hop. And more sensitive to my need to change direction as I pass through two shoulder-width trees and need to avoid a third tree that encroaches the path.

Now I’m no expert at the workings of front and rear suspension systems, but I do know that the suspension has to be set up for your weight and riding style. The right setting can make you faster, the bike more controlable, and the ride more enjoyable.
  • Check the air pressure in your fork each season. The manufacturer usually recommends air pressure for your weight, and you should check it annually. Either the shocks will lose some seal contact or your  weight may be different.
  • Each time you ride, check the amount of displacement as you mount the bike. Both the front shocks and rear suspension should drop about 20% of the available movement. 
So what does the setup do for your ride? Less drop means a stiffer setup, more drop a more cushioned ride.
  • A stiffer setup loses the full travel of your suspension, and the bike bounces more through rocky terrain instead of smoothly tracking through. You may loose traction in corners, too. 
  • Too much cushioning can allow the suspension to bottom out on bigger hits, and you may feel like you’re riding a sofa with worn springs.
But remember that your tire type and the tire pressure contribute to control and responsiveness. The choice of tire type is a long discussion, but the depth of tread, tire width, and flexibility should be appropriate to your usual trail. You can experiment with changes in air pressure on a couple rides. Raise the air pressure to slow the rebound, lower it to increase rebound. Make air pressure changes of about 5psi, which should result in a big difference.

Thanks to for many ideas in this post.

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