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Product Information

Bottom Brackets: 

How do I measure a Bottom Bracket? 

Bottom Brackets are designated by 2 pieces of information. Bottom bracket shell width and spindle length. The bottom bracket shell is the part of the frame into which the BB threads in. All bottom bracket shell sizes are 68mm, 70mm, or 73mm. By measuring the shell is very easy it can be determined quite simply by turning your bike upside down and measuring the width of the frame material that the bottom bracket resides in. To find the spindle length first remove the crank arms. Then measure the length of the spindle in millimeters from end to end. If your crank set is attached with nuts as opposed to bolts, do not measure the extended threaded portions of the spindle. If you are replacing a B.B and are using your old crank, you’ll want a replacement bottom bracket with the same spindle length. If you are installing a new crank set, you will want to use the spindle length recommended by the manufacturer’s crank manufacturer

Different Styles of Bottom Brackets: 


The I.S.I.S International standard is used on bottom brackets from Race Face, Tru Vativ and others. Isis uses a splined system similar to (but not compatible) with Shimano. Isis cranks and bottom brackets are available from a variety of manufacturers, including Race Face and Tru Vativ.

Square Taper:

Conventional square taper bottom brackets are becoming less common on both mountain and road bikes. This style of B.B is identified by the square mounting hole in the cranks and square shape in bottom bracket spindle .

HollowTech II:

The Shimano HollowTech II line of bottom brackets are splined so you will have to use a Shimano splined crankset. The Shimano XTR cranksets are only compatible with Shimano XTR bottom brackets. LX and XT bottom brackets are only compatible with LX or XT cranksets. 

HollowTech II / X-Type / MegaExo:

This is the newest bottom bracket technology. These types of bottom brackets are used with a two piece crankset. The drive side crank arm and spindle are constructed into one piece and the non-drive side simply clamps on to the spindle. Not only does this create better torque it also allows for the crankset to be lighter as a whole. These outboard bearing systems are considerably strong and lightweight.

Braking Systems:

Choosing the right v brakes for your mountain bike:

The most common type of brakes are still V-brakes These brakes are typically cable operated and work by squeezing brake pads to the rim. In order to use V-brakes, you need to have the appropriate v-brake post braze-ons on your frame and fork. Most bikes are equipped with V-brakes and braze-ons as they come from the factory, and can be easily upgraded to different V-brakes if you desire. Any type of hub can be used on a bike with V-brakes. Since all V-brakes are pulled with standard brake cables, any V-brake compatible brake lever can typically be used.

Disc Brakes:

Disc brakes are gaining in popularity. This style of brakes works by squeezing brake pads against a rotor mounted on the bike's hub. Because disc brakes offer more powerful braking, they are typically used on more aggressive bikes, such as those used for downhilling and freeriding. Some systems are actuated by a steel cable, while others use hydraulic fluid. In order to use disc brakes, your frame or fork must have appropriate mounting holes on your frame, and fork. You'll need a set of discs which are compatible with your frame's mounting holes. Additionally, your hubs must be disc brake compatible so that the rotor can be mounted. Disc brakes are typically sold as a set which includes the calipers, rotor, and brake lever. Please ask our tech support for any additional questions.

When I order a Cassette what Gear range is right for me?

When ordering a cassette the numbers you see relate to the number of teeth on the small and largest cogs. A smaller first number will give you more top end speed, while a larger second number will give you an easier gear for climbing. A closer ratio between cassettes will also have smoother shifting. Racers like to have closer ratio so that they can have smooth acceleration and may not have to do really hard climbing. 
Newer riders will want to choose a cassette that has a comfortable upper range. Racers choose one of the cassettes with a smaller cog, and a narrower range. If you have any questions about choosing the correct Cassette please call our technical support department at 800-585-4137. 

Mountain and Road Bicycle Chains:

What chain is compatible with my bike? 

Current mountain and road bikes use 11 speed drivetrains. Using a 10 speed chain will not be compatible with your 11 speed drivetrain. Purchase a chain that is specific with your rear cassette. Count the rings on the rear cassette, and if you have 11 gears, you will need to purchase a chain specific for 11 speed. For awesome results choose a high quality chain from Shimano, or Sram. 

How do I install my chain?

The first thing to consider when installing a chain, is the chain length. There are some methods that you can use to find out your chain length any of these methods may appeal to your situation. The existing chain method is simple before removing the old chain, check the bike for acceptable length. Cut the new chain relative to the old chain length and there you go. Second method (largest cog to largest chainring) Remove your existing chain shift the front derailleur over the largest chainring, and the rear derailleur on the smallest cog. Simply wrap the chain around the largest front chainring and around the largest rear cog. Pull the chain tight, and note the closest rivet where the two could be joined. Then subtract two rivets you can then string the chain through the both derailleurs and check that the chain can be shifted onto all gears without tension, or sag. 


How to measure your chain rings?

Chainrings are usually stamped with sizes (58/94) 5-arm compact, (74/110) 5-arm standard or (64/104) 4-arm. To select one, you'll need to know three things. The number of mounting bolts 4,or 5 arm. Second the number of teeth on the chainring, and last the Bolt Circle Diameter (BCD). You can count each individual teeth on your chainrings to obtain the correct sizing. The bolt circle diameter is equal to the diameter of an imaginary circle drawn through the center of the bolts which secure the chainring to the cranks, measured in millimeters. Regardless of whether the crank has 4 arms or 5 arms, the BCD is measured the same way. There are three different sets of Bcd's are common on mountain bikes. First a 58mm (inner) and 94mm (middle, outer). Second is 74mm (inner) and 110mm (middle,outer) set up. Third is a 64mm (inner) and 104 (middle, outer) configuration. If you have any questions about choosing the correct chainrings, Please call our Technical Support Department at 800-585-4137.  

Are 11 speed chainrings compatible with a 10 speed setup?

No, using the incorrect ring type can bring many problems for example: over- shifts unsuccessful shifts- skipping and chain suck. Always use the appropriate chain and chainring combination for flawless shifting. 


What Types of fabric is used in cycling-clothing?

Cycling clothing specific to the cyclist is mostly constructed with advanced synthetic materials that have a wiking attribute. This means the fabric pulls moisture away from your skin and disperses it throughout the material where it can evaporate easily, keeping your cool and dry. On longer rides cycling apparel will be more comfortable and will maintain your body temperature more effective than with your normal standard T shirt and shorts. Cycling shorts also have a "chamois" or a pad built into the crotch to provide added comfort while riding. Baggy/Freeride shorts often have a built in inner short with chamois. Other fabrics used are drylete, and fieldsensor. These two advanced lycra polyesters are often used in the production of shorts and tights. This material is known for the advantages of being stretchable, durable fade-resistant, and easy to care for. Cycling apparel made from these advanced materials will be more comfortable for long rides than your usual standard wear, and they will last longer than your inexpensive cotton basics.


How do I measure my crank arm length?

Crank arm length is measured in millimeters from the center of the crank bolt to the center of the pedal spindle (where the pedal attaches to the crank arm). The most common sizes for crank arms are 165mm, 170mm, 172.5mm, 175mm and 180mm. Crank arm length is generally a function of two characteristics; leg and riding style.

What I need to know when shopping for a new crankset?

First make sure your crankset will be compatible with all your other parts. Secondly make sure the bottom bracket spindle will be compatible with your new crankset. The spindle required is dependent upon the crankset and bike frame selected. It is imperative that the spindle length is correct for optimum chainline.

Crank Arm Length:

Unless it is stated otherwise, all the cranksets we sell for mountain bikes are either 170mm, or 175mm crank arm length. Road cranks are available in a variety of lengths (170mm, 172.5mm, and 175mm).

Front Derailleurs:

Conversion chart
1 1/8" = 28.6mm 1 1/4" = 31.8mm 1 3/8" = 34.9mm
If you are unsure what size you need, look at your front derailleur. Somewhere on the clamp, the diameter will be stamped in millimeters. You may have to remove the derailleur as the size may be stamped on the inside of the clamp. You will also need to know what pull direction your derailleur is. This refers to whether the shifter cable pulls the derailleur from the top or the bottom, and are called top pull and bottom pull logically enough.

Top Pull or Bottom Pull? 

If the cable approaches the derailleur from above, it is top pull. If the cable comes up from underneath the bottom bracket, it is bottom pull.

Top-Swing or Bottom-Swing? 

If the clamp for the derailleur is below the pivot (the part that moves to guide the chain to a different gear), it is considered top swing. If the clamp for the derailleur is above the pivot, it is bottom swing.

What does "E-type" mean? 

"E-type" refers to a front derailleur that mounts to the bottom bracket of your bike instead of clamping onto your seat tube. This is mainly used on full suspension bikes that have an interrupted seat tube.

Rear Derailleurs:

How does cage length affect shifting?

Shorter cage rear derailleur’s take up less chain slack than a longer cage rear derailleur. The chain is held more snugly, which can result in smoother, more precise shifting. However, longer cage rear derailleur’s are capable of taking up more chain slack than a short cage rear derailleur, allowing you to run a wider range drivetrain than would be possible with a short cage rear derailleur. 
On a mountain bike, your choice is slightly more difficult. Less experienced riders or riders who ride frequently in steep terrain should probably stick to a long cage rear derailleur. This, combined with proper chain length, will allow the bike to be safely shifted into every gear on the bike. Racers might appreciate the lighter weight and slight shifting improvement a short cage rear derailleur offers. However, these benefits come with a tradeoff - because of the decreased capacity a short or medium cage rear derailleur offers; it may not be possible to safely use the small chainring in tandem with the smallest cogs. (The derailleur simply can't take up enough slack in the chain)
For mountain bikes, when in doubt, choose a long cage rear derailleur, unless you are certain you understand the limitations of a short/medium cage derailleur.

SRAM Series derailleurs:  

The SRAM ESP line of components uses a different cable pull ratio than Shimano components. If you have a SRAM ESP series rear derailleur, you'll need to choose matching SRAM ESP shifters.

Suspension Forks: 

Do I need a 1" or 1 1/8" or tapered fork?

You can measure the diameter of the steerer tube of your current fork, which comes down out of your frame where your fork blades meet above the wheel. This is the part that runs up into your head tube. Most mountain bikes require 1 1/8". To be sure, simply measure the diameter of the tube, the distance from one side of the outside wall of the tube to the other. If you are unsure you can always call our sales department.

Do I need Threaded or Threadless?

 In a threadless system the fork's steerer tube will slide through the headtube of your bike and the stem will clamp on to the portion of the steerer tube that rises above the headset. In all threaded systems the fork's steerer tube goes into the headtube but does not pass through the top of your headset. In this system the stem (somewhat "L" shaped) inserts directly into the headset and fork's steerer tube.
Most new bikes are already threadless, so the only concern you have is the diameter of the steer tube (1" , 1 1/8", 1 1/4", 1 1/2"- inch). You can measure this by loosening and removing your stem from the fork , and measuring the outer diameter of the steerer directly. Threadless forks need to use a threadless headset, and stem. Threaded forks use a threaded headset and stem with a quill.

Suspension Fork Travel: 

Consider frame geometry before purchasing a fork, Unless your frame was designed specifically for a long travel fork, adding a shock with a large amount of travel will dramatically change the handling and geometry of your bike. Consider a fork with less travel. 
Similarly, if you already have a frame with a long travel rear suspension setup, you'll want to choose a suitable long travel front fork to complement the rear suspension.
Please contact our Technical Support Department for any additional questions at 800-585-4137.


What is my glove size? 

Hold your palm out flat and use a tape measure around your hand at it's fullest point, not including your thumb. Use the following chart to convert to standard glove sizing. 

Sizes: S (8")/ M (9") / L (10") / XL (11")
Hand measure should be taken around the fullest part of the hand not including the thumb. If right-handed, use right hand and vice versa

glove size chart


As far as MTB handlebars go, there are 2 common clamp diameter sizes - 25.4 and 31.8mm.  31.8mm is the most common size these days. It has been in use for quite some time, as it allows strength and weight savings compared to the older 25.4mm style. If you have a 25.4 handlebar, you need to match the stem with a 25.4mm clamp size. This is also true with the 31.8mm, you need to match the stem with a 31.8mm clamp size. 

Types of handlebars: 

There are 2 basic handlebars used for mtb riding. There are flat bars and riser bars. Flat bars are exactly that, flat. They often have a slight rearward sweep to them, usually 3-5 degrees. Flat bars lower the rider's position. For XC use, flat bars create a more aggressive, hunched over position and weight is more evenly distributed across the bike. Flat bars are typically lighter weight because they don't need to be reinforced at the bending points like a riser bar does. Most flat bars are 22.5-25" wide. Riser bars usually have a rise of 1"-2.5" a slight upward sweep of 3-5 degrees, and a rearward sweep back towards the ride of 5-9 degrees. Riser bars elevate the hand position of the rider. This causes the rider to sit up more, putting more weight on the rear wheel. Riser bars are usually wider than flat bars, typically 25-27" wide. Many people choose to use riser bars because the width gives them more leverage. Single speeders love the extra torque they get from using a wider bar. They also give you more stability. They are also heavier, because they need to have extra material to reinforce the areas that bend. 


There are a multiple headset sizes available, but the most common headset sizes - 1", 1-1/8", 1 -1/4 and 1.5". Well, to be honest, 1-1/8" is the real common size. 1" headsets are still found on a few road bikes, but are rarely found on new bikes. The larger size, 1-1/4", was very often found on Tandems, but are almost obsolete. 1-1/8" to 1.5" (Tapered) is a new trend called one point five. The size refers to the diameter of the steerer tube. The top of the steer tube uses the smaller 1 1/8" then flares to a larger diameter 1.5".  You will have to use two different headset cup sizes to accommodate the tapered steer tube. 

Is my headset threaded or threadless? 

You can determine this by looking at the stem. If your stem is threadless so is your headset. You can tell if your headset is threadless by looking at the stem. If your stem clamps directly onto your fork's steerer tube it is threadless (there are usually two bolts on the back of the stem). If your stem slides directly down into the frame you have a threaded stem, and headset (the only bolt you see is on top of the stem). 

What materials are headsets made from?

Headsets are typically made out of either steel or aluminum.  Aluminum is a lighter material, and is typically found on higher end headsets. Headset bearings differ in quality, as well as design. Less expensive headsets usually come with plain ball bearings in a bearing retainer. They can be easily repacked and replaced. Some people prefer the service ability of loose bearings, but nowadays, more and more companies are coming out with sealed cartridge bearing headsets. Cartridge bearings are simple, and don't need the attention that loose bearings do. Most headsets over $40 will have cartridge bearings.
A lot of people ask what 'stack height' means. The stack height of a headset is the amount of space that it takes up. If you add the stack height to the head tube length and the stem height, (and any desired spacers), and subtract 2-3mm, you get the necessary steerer tube length.  


You can use a measuring tape to determine your helmet size. Measure your head just above your eyebrows, and convert the measurement into the manufactures sizing chart. Please contact us if you need any assistance.

 helmet size chart


Do cleats come with pedals or shoes?

Cleats will come with the pedals and not the shoes. All clipless pedals will include the cleats, and all hardware.

Types of Pedals: 

Your primary choice in pedals is platform vs clipless. Mtb riders, racers and cross-country mountain bike riders will probably prefer a clipless system. In a clipless system, a cleat is mounted to the bottom of the shoe it snaps into the pedal providing a firm and secure attachment similar to a ski binding. The rider can release from the system by twisting their foot to the side. Downhill, Freeride, and other aggressive mountain bikers prefer a platform pedal system, which provides a flat grippy surface without binding mechanism. This style of pedal is also ideal for your casual " around the town" riders who don't want to bother with special shoes.

What are SPD Pedals?

It stands for: SHIMANO PEDAL DYNAMICS and it describes all of Shimano's current mountain bike pedals and the sole drilling that their cleat need. Spd compatible shoes have 2 or 4 threaded holes in parallel slots(1 or 2 holes/slot) under the ball of the foot. The slots are ¨ö" apart and run front to rear. Many different brands and shapes of cleat attach using this bolt pattern. For example speedplay frogs, crank bros eggbeaters, time atac and Shimano Spd's all require the Spd bolt pattern but none of their cleats interchange.

Pedal Size Threading.

All modern mountain and road bikes take a 9/16" pedals. Many Bmx bikes need ¨ö" pedals which are not compatible.

How do I install my new pedals?

You can use a 15mm wrench for all pedals some of them also allow for a 8mm allen wrench to be used. Keep in mind that the left pedal is reverse threaded, so you screw it counter-clockwise to tighten, and clockwise to loosen.

What is the easiest way to disengage from my clipless pedals?

There is definitely a learning curve when you are adjusting to a new set of pedals especially if you have never used clipless before. Just turn your ankle slightly away from your bike and your cleat will click right out of the pedal. Take a few rides to get use too, and it will just become second nature. Keep your pedals clean for them to release easily, and consistently. Spray off your pedals with a hose to take all the muck out and keep the pins and springs lubed with some thicker oil to reduce wear and tear.

Bicycle Seats:

How can I select a comfortable saddle with so many to choices?

Choosing a saddle is a personal matter. There is no way to guarantee a successful mating of butt, and saddle. If there is a specific style, or profile that has been working in the past We would suggest sticking to a similar style. Remember, any new saddle will take time to break in, and the more miles you ride the more comfortable your saddle gets.

Titanium, or Chromoly rails?

Chromoly rails are often used in most saddles. Chromoly (Chrome Molybdenum) is a strong, durable and resist bending, and is not as expensive as Titanium rails. If you're looking to save a little more weight on your saddle use Titanium rails. Titanium rails often require special workmanship, so these saddles tend to be more expensive than their chromoly-railed counterparts.

How can I find my seatpost size?

Most seatpost manufactures will stamp the seatpost size near the maximum height line. If it's not stamped your local bicycle dealer or the manufacture of your frame can help you determine the proper size.

Suspension Seatpost

Suspension seatpost add comfort to the ride of a hardtail frame. It's a simple, and cost effective upgrade. If you're currently riding a hardtail, but not ready for a full suspension bike, a suspension seatpost will definitely bridge the gap. Ask our technical support about adding a suspension seatpost to your bike.


What is STI?

Shimano's STI (Shimano Total Integration) merges the shifters with the brake levers. Shifters are generally compatible with matching derailleurs. Example; most 8 speed shifters are compatible with 8 speed drivetrains, and 9 speed shifters are compatible with 9 speed drive trains with very few exceptions.

Grip Shift

SRAM's Grip Shift is also very popular with the mountain bike set; it integrates the shifter with the grip, so shifting is accomplished by twisting a section of the grip itself, much like the throttle on a motorcycle.

Shifter Compatibility

For mountain bikes, the only notable components which are NOT interchangeable are the SRAM ESP series of shifters and derailleurs. SRAM's ESP shifter pulls a different amount of cable than Shimano shifters, thus, the two are incompatible. If you are using a SRAM ESP shifter, you'll need to choose a matching ESP rear derailleur. (Please note that SRAM non-ESP shifters ARE compatible with Shimano derailleurs.)

Bicycle Stems:

How do I measure the length or extension of my stem?

The Most important size you need is the clamp diameter. There are usually four sizes that are used while purchasing a stem. These are all the four different sizes. 1", 1 1/8", 1 1/4" or 1 ¨ö". By far, the most common size is 1 1/8", used on almost all mountain bikes and many road bikes. Some road bikes use 1". Finally, 1 1/4" is used by a few rare mountain bikes. Stems also come in various lengths so you can achieve a more precise fit on your bike.  Another size that will come across will be the rise of the stem, and length this depends on what is comfortable for you. Stems come in different lengths so that you can get a more comfortable fit on your bike. If your upper body and arms are long or you like to be stretched out a bit, you might like a longer stem. Stems also have varying degrees of rise so you can really dial-in your riding position. Freeriders/DH, would prefer going with a shorter stem to have more control while descending, and cross country riders would prefer a longer stem for the steep climbs, but remember what is comfortable for you. Also some people with chronic back or neck injuries prefer stems with a higher rise, so that they sit more upright on the bike. Many riders like stems with zero degrees of rise, or even a negative rise, so they can ride in a more aerodynamic position as well.

Purchasing the correct stem length:

Choosing a stem depends on what is comfortable for you. There are two different styles of stems- threaded, and threadless style.
The older threaded style, the stem is inserted inside the fork's steer tube and secured with a wedge. Newer threadless your stem clamps directly onto your fork's steer tube there are usually two bolts on the back of the stem). Modern mountain and road frames are using the threadless set up.


For choosing the correct size, you'll need to convert your American shoe size into a European measurement. 

Clipless Shoes: 

Your cycling shoes have stiffer soles than your standard running shoe. A stiffer sole will allow your pedal stroke to be more efficient and transfer more power directly through your foot to the pedals. This translates directly to more control of your bicycle, and comfort on longer rides. There are many benefits to using clipless style shoes vs a non clipless shoe. Once you decide what type of shoe to use please make sure your shoes are compatible with your pedals. Mountain bike shoes offer SPD two hole style cleat, and road bike shoes offer a 3 hole cleat.

Does the cleats come with my shoes?

Cleats will come with pedals and not the shoes. All clipless style pedals will include cleats and mounting hardware. 


Are my new wheels ready to ride?  

Yes, most of the wheels we sell are ready to ride, you will have to install rim strips (sold separately) to cover the spoke holes.  Install tubes and tires and you're off to the races. Most wheels will need to be trued after your first few rides to make sure that the spoke tension is maintained as the wheels break in. Truing wheels can be difficult, so we recommend taking them to a certified mechanic. All of our wheels come pre-built and trued. Further truing may be required and is expected after your first rides. This is the buyer's responsibility to check spoke tension and Blue Sky Cycling is not responsible for any charges adhered to truing.  Bent or broken spokes or rims are not covered under warranty. 

What is the best set of wheels for my type of riding? 

You need to consider what type of riding you do and what factors are most important to you. If you do mainly cross-country riding you want a lightweight set. For DH or Freeride or all All mountain, you need a wider rim with a thru axle for strength and stiffness. 

What are the difference in construction of wheels? 

Traditional wheelsets are laced with either 32 or 36 hole spokes. A 36 hole wheelset will be stronger but will also be heavier. There are many lightweight wheelsets available that have alternate spoke designs, ie. fewer spokes, 3 cross lacing, or radial lacing. The correct choice depends on the type of riding you do and how often you ride.  Please contact our technical department for additional information 800-585-4137. 












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