Two Pathetically Basic Mechanical Questions

[Ben_Ricci]

I have two pathetically basic questions. One is suspension-oriented and the other is mechanical.

 

1. What is the practical difference between having one’s bike set up for solo or two-up riding? I know the preload and damping are changed to accommodate the extra weight of the passenger, but can I leave my bike set up for two-up riding because of the relative inconvenience of changing preload/damping and tire pressure? I’m 155 lbs. and I probably carry about 10 pounds of junk with me: rain suit, tools, extra gloves, etc. My wife probably weighs the same (she won’t say exactly ).

 

2. I scratched the valve cover on the right side of my bike on some rocks when I dropped it getting off on a muddy road back in December. It’s not terribly obvious, but it’s like a dent in a car door: every time I look at the bike, I see the scratches. If I wanted to replace it, all I need is a new cover, gasket, the torque values for the bolts and a little bit of oil to replace what trickles out, correct? Is it this simple or I have missed something?

 

Thanks .

 

Ben

[steve.foote]

Ben, question 1 is not really that simple. So, I'll begin with #2.

 

All you would need is the valve cover itself. You can reuse the seals and the oil loss is negligble. You may get lucky and find a blemish-free cover on the internet, or put on head guards to cover the scratches and forget about it.

 

As for suspension, you'll have to do some experimentation. Rear sag is not an exact science and deals with the variations of weight and feel for the rider. If the suspension is too soft for the load, you'll wallow in turns and likely bottom out on bumps. If it's too hard, the rear will bounce on bumps which is just as bad. I'd get used to cranking the preload when you make changes.

 

As for tire pressure, you can run the higher pressure if the ride quality is not a problem.

[Mike]

Ben--

 

I'll tackle item # 1. Yes, you can leave your bike set up for two-up riding. If you're constantly switching back and forth between solo and two-up riding and don't want to fiddle with the suspension each time, that's the configuration I think would be preferable. The primary issue you'll run into if you do this is that your suspension will feel stiffer and will be less compliant when you are riding solo. Apart from the question of comfort, the lack of suspension compliance means that you'll give us some control since the stiff configuration will mean that your tires will tend to bounce over surface irregularities, rather than remaining in contact with the pavement.

 

If, on the other hand, you keep your suspension set up for solo riding, your bike will feel squishy when you ride two-up, and you'll be more likely to have the suspension bottom out when you hit larger bumps.

 

I'm no genius when it comes to suspension setup, but everything's pretty easy to get to on the ST. I'd suggest that you try settin the bike up for solo and two-up riding, then record the settings. It shouldn't take more than a couple of minutes to switch things over once you know the proper settings.

[Ken H.]

OK I'll make a small argument as to why you might not want to leave the bike set up for two-up when solo... And that is because of the optimum range of the total travel. If preload is too tight you will be in the upper 1/3, maybe 1/4 even, of the total available suspension travel and the bike may not have enough headroom to maintain proper control all surfaces.

 

OTOH, if it feels fine to you, just ride and forget I guess!

[Paul Mihalka]

Ben,

Scratches on valve cover: To replace the cover you need exactly what you listed. Would a set of valve cover guards cover up the scratches? You install the guards, and if it happens to fall over again (sxxt happens) nothing gets damaged.

Rear shock preload: There is a ideal static position of the shock that is adjusted to confirm to the carried load. With the full load on the bike the shock should be somewhat compressed to the point that about 2/3 of total shock travel is available for compression, and 1/3 for extension. If there is not enough preload the shock will bottom out hitting hard when it is completely compressed. If there is too much preload the shock will go prematurely to full extension. This is called topping out. None of the two conditions are good. Obviously the load weight has to be within the design range of the shock.

[Ben_Ricci]

Thanks Steve, Mike, Ken and Paul. I understand the settings now.

 

As for the scratched covers, the marks are almost vertical because the bike literally fell straight over on a few rocks embedded in the mud.

[gasser]

And I thought I was the only one that has ever dropped a bike on its side. You're right, changing the cover is a great idea; otherwise, you might as well hang a sign on the bike that says, "Guess who dropped it?" I bought my side cover on ebay and paid about $90 for a new "old" one.

[ShovelStrokeEd]

#2 first. Just kick the thing over on the other side and make it symetrical.

 

#1 is much more complex. Preload will allow you to reach a compromise setting for what is really a spring that needs to be changed each time you make a substantial change (10% of total weight) in the load on the bike. Nobody is gonna change springs however. So, let's look and see where your at.

 

As a solo rider with 10 or so lbs of extra crap, your spring rate, at your weight, is probably right on the money. You should be running pretty close to zero preload right now. Crank in a couple of turns on the knob for when you add the S.O. the extra stuff she is likely to bring. Shouldn't take more than a minute to do. Unless you plan on racing with SO aboard, you probably won't need to touch the damping much. Maybe a click or so on the rebound if you are really picky.