Few minor issues
 

I recently purchased a 7.4 FX - Trek Bicycle

I put over 100 miles on it within the first week and I'm already noticing a few things. I ride everywhere from paved roads to seldom off road. I weigh 170LB

- When I ride against strong winds, my bike makes squeaky noises like the sound of nudging an unsteady chair. I often mistaken the sound for a squirrel or some small animal... but it's definitely the bike and I don't know what it may be? Makes no noise under moderate wind

- The chain 'derailed' twice within two days. First occurrence was at night when I accidentally collided with another cyclist at no more than 10MPH. The impact was so minor we both remained mounted on our bikes, but I was unable to pedal - how can a head on collision derail the chain so easily? Another occurred today while sketching out a field, I went off road and onto shallow sand - then hit some flat object that looked like the remains of a traffic cone. The object was completely plastic with no jagged metals sticking out or anything. Minus a little grime on the hands, it is a simple fix but it baffles me how easily the chain can derail. How bad is derailing for the bike? Is it possible to keep a tenacious chain?

- I notice the spokes on the front wheel bending as I drop from high sidewalks or hit wicked potholes... I know they are absorbing the impact but is there a threshold? Will the spokes/wheel/fork give easily? In NYC running through these are inevitable and I am concerned with the longevity of this bike. This bike seems a little fragile...:crash:

Think about how your drive train is designed - the whole idea is to have a chain that can move sideways from one sprocket to another.
Sometimes a bad rattle is enough to upset the chain sufficiently to jump to another sprocket. A light nudge sideways on the chain or the derailer can do it. Unless the chain falls off completely, don't worry about it. If it does, check limit screws and chain length. Derailing is annoying but usually not harmful. Jamming the chain in between spokes and sprocket can damage the spokes though. Chain suck - when the chain fails to disengage the chainring and bunch up instead can damage both front derailer and frame, depending on where it happens.

The noise is probably a squeak brought on by you putting more effort into the bike. These can be real hard to track down. Can be in the bar/stem/fork interfaces, can be bottom bracket, can be saddle, can be pedals... disassemble, lube and reassemble are the usual recommendations.

I don't think you really see the spokes bending. That was the case, the wheel would collapse. And it looks like 32-spoke, which should be sturdy enough for most use.
Stationary, regular wheels are quoted to stand something like 500-600 lbs before collapsing. Dynamically, it'll be less of course. But outside a crash scenario, the likely killer of a wheel is either spoke fatigue, brake track wear or point damage to the rim from hitting a curb or a pothole.

I suspect if the chain derails were because a jolt caused the chain to jump or whip a bit (the rear der cage would play out a little then it's spring will pull tight again). If there was any back pedaling at the same time the chain's jumping could allow a derailment. This is very common when riding off road, hence the "clutched" rear cage pivot designs that have come to the market lately.

The squeak might be a hub seal rubbing against the hub shell. Some hubs have an outer "rubber" seal that sits on the axle and rides snug up against the shell. This interface can produce a noise often described as a squeak. A drop of light oil (Triflow in our shop) between the seal and shell cures this. A greater concern is if the seat post, handle bars or the cranks are the source. Sometimes an imperceptible amount of movement/wiggle can be happening and all that is observed is are creaks/clicks or ticks when really pedaling hard.

I also doubt that the spokes are going through so much stress that you can see then flexing. When you're moving around on the bike from the shocks and forces that jumps, drop offs and sharp jolts produce it's real hard to keep your eyes steady enough to discern what's actually happening. When the rim becomes permanently deformed (gets dented or flat spotted) you'll know that you've exceeded it's limits.

The FX series bikes are not meant to be ridden in the same aggressive manor as a mountain bike. They are intended for prepared and firm surfaces (pavement, bike paths, smooth dirt roads. As the cost level goes up (as in the 7.2 compared to the 7.4) the components get lighter, work nicer and potentially (with equal maintenance) have there better feel last longer. But some of the robustness of the wheels and tires is also taken out of the bike as a means to achieve the lighter and more responsive ride. Riders can ride skinny wheeled bikes off road without problems if they're skilled (cycle cross racing) and riders can bend strong mountain bike wheels riding on roads if they're not paying attention. How well your bike works and lasts is totally up to you, the rider. Your bike does not decide which bump it will ride over, or avoid. Andy.

The reason people are doubting the spoke flexing description, is that there's nothing holding on to the rim end of the spoke. If you put enough force on the rim to cause it to deflect (bend towards the hub), the spokes on that side wouldn't bend, they'd just push deeper into the rim. The only way to see spokes flex is if you put a large sideways load on the rim. And even then the amount of flex you're likely to get is too small for a rider to easily see (though it can often be felt).

The amount of curb hopping, pothole smashing madness your bike can withstand depends on the rider and how you ride. A 140 lb rider going off a curb is going to have a lot less energy to absorb on impact than a 240 lb rider. But how quickly the energy has to be absorbed also makes a difference. Using your legs to dampen impacts spreads out the energy with respect to time resulting in much less stress on the bike (and the rider). If you're going off curbs with your butt planted on the saddle, neither you nor the bike are likely to tolerate that abuse for long :)

The fact that you haven't mentioned flats says that you're probably not riding as hard as it sounds. The tires on the bike are taking the brunt of the impact energy. If you push too hard, you'll start to suffer pinch-flats where the inner tube gets pinched between the tire and the rim on hard impacts and gets a little hole on each side. Assuming you're not getting those (and that you haven't pumped up your 35c tires to 120psi to avoid them), you probably don't have much to worry about.

Actually, the OP's description seems like fairly abusive riding. Fortunately, bikes are simple machines and tolerate abuse fairly well, responding with small issues like dropping the chain.