Kevlar Mountain Bike Tires by Specialized or How To Avoid Punctures

Specialized introduces the anti puncture bike tires Armandillo Anti Flat Technology.

Basically the tires have a nylon and Kevlar layer underneath the outer rubber. So you can ride long distances on rough terrain without the worries of getting a flat tire.

What Is Rebound Damping in a Mountain Bike Suspension Fork - Video

So what is rebound damping in a MTB suspension fork really?

Think about this - every time you ride over an obstacle on the mountain bike trail, your front wheel takes the shock. The suspension fork compresses as to absorb the impact shock and then it bounces right back. The rebound damping mechanism controls the speed at which the the fork comes back.

Keeping the tire in permanent contact with the ground is the main job of this mechanism. You can control the rebound depending on the terrain you're rolling. Leaving the rebound in the fast mode means your fork will bounce back quickly, transferring the force into your arms through the handlebar and making the front wheel loose contact with the ground. Instead of having a smooth ride you get a bumpy run. That's why keeping the rebound lever somewhere in the middle is advisable.

If it takes a fraction of a second for the fork to sink as you hit a rock or dip into a hole in the trail, then the fork will come back to its initial state in more than one second when the rebound is on slow mode. This is good for you (the cyclist) because you can keep control of your bike (direction) due to the permanent grip between the tire tread and the trail - which is granted by the slow rebound.

Adjusting Front Suspension Damper Settings on Downhill Mountain Bikes


Happy cycling!

What's the Purpose of the Rim Groove in Your MTB Wheel

You may have noticed some grooves on the rims of your mountain bike wheels.

Since it's easy for you to observe when the rubber brake pads in your V brakes are worn out, it's not as easy to notice when the wheel rims have gotten too thin. That's what the grooves tell you.

The bicycle wheel rim deteriorates just like any piece that is subjected to constant contact and friction with another piece (brake pad). This is true especially if you ride a lot on muddy singletracks - sand, mud and other abrasive materials caught between the brake pads and the rims accelerate wear and tear. Of course, if your MTB has disk brakes, you won't confront with these issues.

So what you need to do is to check the rims regularly as to see if the grooves are still visible. If the rim has gotten flat this means it's time to replace it with a new one (or buy a new wheel altogether). This will prevent the rim to get too thin (so thin that the tube becomes visible - it might even explode). Basically, the excess aluminum on the rim (in which the groove is carved) acts as a wear and tear meter. 

Groove still visible in my rear wheel - OK!

Front wheel needs to be replaced - the groove is no longer visible
 NOT OK! (the rim is worn out)

Wear a cool bike T-shirt while riding! :-)

Why Disk Brakes Are Better Than V Brakes on a Mountain Bike

Update: You might as well skip this post and go straight to the comments section where Remus made it clear why disk brakes are more efficient than V brakes.

There's a reason why disk brakes are better than V brakes on a mountain bike and it has nothing to do with the usual arguments: no mud and no water reaches the disks thus the braking is more efficient - unlike the rims which easily gather mud, sand and water while crossing streams, making it harder for the cyclist to stop the bike (not only that but the brake pads and the rims themselves are worn out by the abrasive materials caught between them, which not cool...).

But the real reason rim brakes are less efficient than disk brakes consists of a simple truth pertaining to physics: it's a lot easier to stop an object moving in slow speed than it is to bring to a halt an object moving in higher velocity.

The vectorized image above depicts a mountain bike wheel equipped with a disk brake system. Notice that the two points (A and B) travel different distances in the same time unit until they reach their destination positions (noted here as A' and B'). Based on this observation it can be stated that, given a certain spoke (radius) of a bicycle wheel (circle), each point of the spoke starting from the hub (center of circle) to the outer margin of the wheel (rim) has its own speed when the wheel is spinning. The further from the center, the higher its speed.

Think of it this way: no matter how fast the wheel is turning, the rim will always spin faster than the brake disk (which is smaller in diameter and has the same center) even though both the disk and the rim (and all points on any given radius for that matter) perform the same number of rotations per time unit. Example: One full spin of the wheel happens in one second - the speed of the valve (taken as a point on the rim) is about 200 cm/second while the speed of the corresponding point on the disk brake is about 60 cm/second.

Since the braking force is applied so close to the wheel's hub there is a need for sturdy spokes in the wheels that have disk brakes on them. Unlike the normal wheels on which the rim is designed to withstand erosion and friction (features needed for V brakes), disk brake wheels come with stronger spokes (double spokes) that distribute the braking force towards the tire without breaking the spokes themselves.

As a side note you may have the disappointment to find that medium bikes that have disk brakes (mechanical system, not hydraulic) do not have such strong rims. So while your bike brakes efficiently you might see that the wheels loose the round shape easily after bumpy downhill rides. This happened to a friend of mine who has a Kona Fire Mountain. A smart thing you can do is replace the rims (or the whole wheels) with ones that are designed for V brakes - they are stronger due to thicker walls; also the sharp U or V section profile makes them hard to bend/break.

Another reason the disk brakes are desirable is because they are thin and ventilated. Also the travel of the brake pads is shorter than in the case of V brakes - the pads are closely positioned sideways from the disk as to apply friction on it after a travel of not more than 2 mm. The holes in the disks allow a better ventilation letting the heat (caused by friction) escape more efficiently.

The rims get hot (after a long downhill ride with V brakes) and transfer the heat to the tires which is not necessarily a smart way of getting rid of heat. While I haven't heard of tires exploding or melting due to hot rims I think we all agree the disk brakes manage to take care both of stopping the bike faster and not damaging the tires through heat transfer.

The same physics law that makes the rim of the wheel move faster than any point situated closer to the center of the wheel is responsible for the noise of the helicopter rotor blade. Some of the noise that we hear in a flying helicopter (bang bang bang) is a series of sonic bangs caused by the tips of the blade which travel through air at supersonic speeds. The longer the blade, the faster the speed of its tip (rotations per minute being constant). Military forces are working to reduce this noise for stealth operations - long-range propagation of helicopter noise can alert an enemy to an incoming helicopter in time to re-orient defenses. Read more about helicopter noise reduction and rotor noise (see page 4).

Want to learn more? Check out a cool article where you can learn about the benefits of having disk brakes on your mountain bike - weight and other technical aspects are being taken into account as well.

Keep riding your bike. And since you love biking so much, why not learn to design your own mountain bike T-shirt or jersey?

Cheers!

Why You Need a Lockout MTB Suspension Fork

Serious mountain bikers usually choose mountain bikes with a lockout front suspension fork. But then again serious cyclists in general are more into cycling than they are into gear. What I mean is you don't have to own the perfect bike to be a good cyclist.

The lockout is a switch/lever on one of the tubes in your MTB fork that once turned makes your fork rigid. Some forks have what is called remote lockout - the lever is placed on the handlebar and thus you don't need to reach down at the fork to operate it. A cable connects the handlebar lever with the actual lockout switch on the top of the fork tube.

What Are the Benefits of Lockout MTB Fork

Having a rigid fork (suspension locked) is useful when riding uphill on even terrain. In this situation you usually get up from the saddle and push on the pedals using your own weight. If you have a regular suspension fork most of your effort dissipates in the fork itself. Instead of transforming your work on the pedals in covered distance you waste energy by allowing the fork to glide back and forth with each push you make.

A rigid fork allows you to transform your pedaling into traveled distance. When riding out of the saddle you won't bounce (as with the suspension on) and you will gain distance more efficiently.


If you ride in the city and cycle in a soft manner (on the saddle) you may want to leave your suspension on as to decrease the breaking distance. Basically the same thing happens here - the kinetic energy is being absorbed by the fork enabling you to stop faster and keep permanent contact between your bike's wheels and the road.

Remote lockout on MTB fork

Pictures taken from here and here (Cozy Beehive - a technical cycling blog).

Go cycling!

Free Downhill T shirt Design

Download this downhill T shirt design in vector format (SVG) here

Aren't we all downhill addicts?

Suggestion for printing your mountain bike T shirt and hoodie

Wear your helmet while riding the single-track!

Are You a Fat Cyclist?

Coz if you are, fat that is, you're not the only one.

I myself gain and consequently struggle to loose about 2 kilos (4.4 lbs) per week so I feel fat pretty often. :-) That's because I like to indulge myself with pork - as you can see in the MTB video "And Mustard Please..."

What you can do for loosing weight is what the Fat Cyclist did for himself:

I had known I needed to lose weight, but hadn’t really done much about it. As I pushed my bike up the road, I realized I had not tried one very successful diet tactic: humiliation. I resolved to start a blog, embarrassing myself by proclaiming my weight on a daily basis, no matter how bad I was doing.

I urge you to read Fatty's blog here and start getting in shape. You can also bring your contribution to the fight against cancer by riding 100 Miles of Nowhere.





My mountain bike downhill video where I get fat...


Enjoy the bike satire!

Awesome Mountain Bike Video

The title says it all: If Only Every Mountain Biking Video Was Shot Like This...

I assume they used a glidecam (Steadicam) with a body vest and flying arm for shooting this footage. It looks that they also had flying cameras on steel cables running above the single track. I can only guess the amount of work behind this free ride MTB clip. Good job guys!

Download this drawing for your mountain bike T shirt or hoodie here.

Keep riding and wear your helmet. Cheers!

Trail Running & Mountain Biking - CPNT Brasov Promo Video - GoPro HD - DIY Glidecam

Here's a short promo video that I made for my friends in CPNT - youth and sport club in Brasov. This clip shows two of their outdoor activities: trail running and mountain biking. They also engage into climbing, trekking and other mountain sports but this action video is supposed to be a digital brochure for their mountain running competition - Marathon 7500 in Bucegi mountains.

If you happen to know any company that you think might sponsor this event please shoot me an email so I can hook them up with CPNT. The more sponsors the event has, the better the prizes you'll get if you hit the podium!

The video was shot with GoPro® HD Video Camera, edited with Magix Edit Pro 11, and I used my DIY glidecam for smooth shooting and image stabilizing. My laptop couldn't export in HD this time - some memory error issue - and that's why the footage looks pixelized...

If you can't import or you can't edit your GoPro HD videos, try to convert the MP4 files to MOV or AVI with MPEG Streamclip.

Go trail running and show us what you got!

Bike Crash Funny Video

Once in a while everyone's bike riding is perturbed by minor or major crashes.That's why protection gear for head and joints is highly recommended for bikers and especially for those who like to push the limits when it comes to speed, tricks and stunts.

However, there's something funny about crashes that leave the biker unharmed and scared. 


Luckily, now we can purchase great portable action cameras in order to document our performance victories and our failures - GoPro Hero camera is the world's smallest, wireless helmet and gear-mountable video camera for outdoor sports.

 A funny bike crash was captured with such a camera by Mihai:

Wear your protection gear and be safe!