Thursday, April 24, 2008

Shaft Drive Bicyle (Chainless)

Shaft Drive

What are the advantages of shaft drive bicycles versus chain bicycles?
How long have shaft drive bikes been around?
How durable is the shaft drive?
How much do shaft drive bikes weigh versus chain bikes?
How will the shaft drive effect or enhance riding performance?
Can existing bikes be retrofitted with a shaft drive?

Gearing

Where are the gears?
How many speeds do chainless bicycles have?
How do you shift gears?
What are the gear ratios for your bikes?
Do all the bicycles use the same shaft drive?
How fast are your bikes?

Ordering

Where can I test ride the bikes?
What is the right bike size for me?
How does Dynamic Bicycles package and ship its bikes?
What assembly is required when I receive the bike?
How are Dynamic Bicycles guaranteed?

Care and Maintenance

What maintenance is required for the shaft drive and internal gears?
What happens if I have problem with the shaft drive?
Where can I get the bike serviced if needed?
How do you remove the rear wheel if you get a flat tire?
What if the gears are slipping - how can you adjust the gears?
How do I adjust the brakes?

Shaft Drive

What are the advantages of shaft drive bicycles versus chain bicycles?
Easier to operate: Simple twist grip shift is convenient, responsive and operates independent of pedaling so you can shift gears anytime, even at a complete stop.
Safer: No chain to fall off; no chain bite on clothing.
Cleaner: Axles and gears are fully enclosed - no grease/oil exposure to get on hands or clothing.
Lower maintenance: Fully enclosed, durable bevel gears are protected from impacts, debris and the elements.
Smoother ride: Fluid shifting and mesh gearing combine to create smoother pedaling and shifting.
Easier to transport: Easy loading and unloading without getting chain grease on hands and clothes.
Lower cost of ownership: Increased durability and drastically decreased maintenance schedule means fewer service and repair costs.

Also see Top 10 Reasons Shaft Drive Bicycles are Better

How long have shaft drive bikes been around?
Shaft drive bikes actually date back to the early 1900's. However, our modern shaft drive has been in production for nearly 10 years. We are currently on our third generation shaft drive. However, until the last several years, shaft drive bikes were limited in popularity due to the limitation of gearing available. Now, with Shimano's advanced 7-speed and 8-speed internal gear hubs, our bikes offer a very wide gear range without all the external moving parts.

How durable is the shaft drive?
Our shaft drive is designed to have twice the life expectancy of a chain under comparable riding conditions. Our shaft drive is made of the highest grade components, is assembled by hand in our own factory, and has been rigorously tested for strength and durability. Our shaft drives are made with:

  • Heat-treated, hardened chromoly spiral bevel gears
  • Heat-treated, hardened chromoly spindle
  • Carbon steel shaft rod
  • Sealed internal precision bearings
  • Precision machined aluminum housing
The shaft drive is also resilient to impacts and is weather resistant for all-season use. Its sealed design makes it better protected from adverse conditions such as sand, dirt, water, salt and grime than any chain bike ever could be.

How much do shaft drive bikes weigh versus chain bikes?
Our mountain, hybrid and road bikes weigh approximately 26-33 lbs. depending on the model. Most people who ride our bikes comment how light our chainless bikes feel, especially compared to other internal hub bikes. In fact, our bikes weigh less than one pound more than a traditional chain bike of the same configuration. In other words, if our same bikes were configured with a chain and sprockets instead of our shaft drive, our shaft drive bike would be less than 1 pound heavier than the chain bike. That means for all the added advantages of our chainless bikes including a smoother ride, smoother shifting, less maintenance, fewer repairs and greater safety, the trade-off is less than 1 pound!

How will the shaft drive effect or enhance riding performance?
Testing has shown that the efficiency of our shaft-drive system is about 92%-94% without regular maintenance. According to Dobrovolsk and Others' "Machine Elements Textbook", the peak efficiency of very expensive chain systems ranges from 95% to 97% (chain-rings in same diameter, chain in perfect alignment and chain in permanent ideal tension). However, typical, averagely maintained chain-derailleur bikes range in efficiency from 75% up to 85%, and can often skip and/or jump gears. This means that for every pedal stroke, shaft drive bicycles will perform more consistently and shift gears more smoothly than a chain bike that is not meticulously cleaned, adjusted and lubricated. This translates into more consistent performance without worrying about adjusting chain tension, aligning chains and derailleurs, and regularly cleaning and lubricating the chains and chain-rings.

Can existing bikes be retrofitted with a shaft drive?
No. The shaft drive requires a specially designed frame. This frame is engineered with a wider and narrower bottom bracket shell and special dropouts where the shaft drive connects to the rear wheel. All of our bicycle frames were designed specifically for use with the shaft drive, ensuring the highest levels of performance, safety, comfort and durability.

Gearing

Where are the gears?
We use Shimano's advanced Nexus internal gear technology. The gears are all neatly tucked away inside the rear wheel axle, These types of internal gears are called hubs. Because all the moving parts are sealed inside the hub, there are no external moving parts to maintain, adjust or clean. Shimano's hubs are sealed and lifetime lubricated to provide many years of worry-free riding.

How many speeds do chainless bicycles have?
Dynamic Bicycles uses the Shimano Nexus 8-speed and 7-speed internal gear hub technology. However, don't let the number of speeds mislead you. With Shimano internal hubs, our bikes provide bigger "steps" between the gears, so a single gear change on our bike is like changing 2-3 gears on a chain bike. In turn, our 8-speed bikes provide the same gear range as 20 gears on a chain bike, and our 7-speed bikes offer the range of 17 gears. This gives you a very wide range of gearing for climbing hills or cruising streets without all the messy, noisy, clumsy external gear components. In essence, internal hubs just eliminate all the redundant, unused gears inherent in chain bikes and provide you with much simplified, more consistent and more reliable gearing. Plus, these hubs are virtually maintenance free, and are integrated directly with the shaft drive.

With chain bikes, changing gears is done by moving derailleurs to manipulate the position of the chain on both the front and rear sprockets. By changing the position of the chain on the sprockets, you change the gear ratio (i.e. the number of rotations of the rear wheel for each rotation of the pedals). For instance, in 4th gear on a 24-speed chain bike, the gear ratio will be about 1.1, which means that for every one full revolution of your pedal, the rear wheel will turn 1.1 times. In 21st gear, the gear ratio is 2.9, which means that for each complete revolution of your pedal, the rear wheel will turn 2.9 times. The downside of gearing on bikes with chains and sprockets is that in order to create the range of gearing for both climbing hills and cruising along on flats, you end up with many, many redundant gears in between. This is why you often times have to switch 2, 3 or 4 gears at a time on a chain bike in order to feel a difference in pedaling. Also on a chain bike, if you want to know what gear you're in, you have look down at the position of the chain on the sprockets, which is awkward and dangerous.

With Dynamic Bicycles' shaft drive and Shimano's internal gear hub, we have a more natural separation between gears so you get a very wide gear range without all the superfluous gears as on chain bikes. Each gear change on our bike provides you a smooth transition to the next speed. We also provide plenty of gearing for climbing hills, cruising on flats and many gears in between. The gear shift indicator tells you what gear you are it at all times, and the single shifter makes it much easier to operate that having to fumble with multiple shifters on each hand.

With shaft drive bikes, one gear change is like changing 2-3 gears on a chain bike. Our 7-speed models offer the range of 17 gears of a chain bike and our 8-speed models offer the range of 20 gears. The 7-speed gear range is our recreational range, giving you the ability to climb hills on paved or packed surfaces with ease, while giving you the high end range to cruise at about 15-20 mph. With the 8-speed, we offer even more flexibility, giving you the ability to nearly match a 24-speed chain bike for high or low end depending on the kind of riding you do most. For a detailed comparison of our gear ratios to that of a chain bike, view our Gear Ratio Chart.

How do you shift gears?
The gearing on our chainless bikes is simpler to operate than a chain bike. All the gearing is controlled with a single shifter on the right hand. Most of our bikes come standard with the twist grip shifter. To change gears, you simply rotate your thumb and forefinger. The gear indicator tells you what gear you are in all the time - no more guess work or looking down at your chain to see what gear you are in. Plus, with our bikes, the shifting is independent of the pedaling, so you can shift at anytime - while pedaling, coasting or even at a complete stop. You can even shift the entire range of gears in a single movement to adjust for changing terrain or respond to road situations without worrying about dropping a chain.

What are the gear ratios for your bikes?
Dynamic's bicycles use the Shimano 7-speed and 8-speed internal hubs to give them a surprisingly wide gear range from a very compact space. Our bikes can offer a gear range comparable to 20 gears on a 24-speed chain bike -- a gear range wider than most traditional 10-speed bikes. For a complete gear ratio chart, please view our Gear Ratio Chart.

Do all the bicycles use the same shaft drive?
Dynamic Bicycles shaft drive is available in 2 different fixed gear ratios: Sport and Street. These fixed gear ratios combine with the Shimano internal gear hub to create the final gearing of the bicycle. The Street shaft drive provides the best gear range for street/path riding with moderately hilly terrain and off-road riding on less aggressive terrain. The Sport shaft drive provides a bit lower gearing which provide the best gearing for steeper uphill and off-road climbing. Most of our bikes are equipped standard with the Street shaft drive. If you would like to order your bicycle with a different shaft drive than what is standard on the bike, please call us to place your order - we will be happy to make this change for a small additional charge. If you would like to replace the shaft drive on one of our bicycles after you have received your bike, you can purchase an additional shaft drive directly from us. Replacement of a shaft drive takes approximately 30 minutes and does not require any special knowledge or skill.

How fast are your bikes?
Dynamic chainless bicycles are not designed for racing or competition. However, they can offer quick cruising speeds for fitness and exercise riding, commuting, and recreational touring. For our 700C hybrid, cross and road bikes, a rider pedaling at 70 rpms in the top gear will cruise at 18-20 mph.

Ordering

Where can I test ride the bikes?
Because we sell primarily direct, our bikes are not readily available in bike shops for test rides. This is why we offer our 30-day money-back guarantee. If after you receive the bike you are not satisfied, you can return it to us for a full refund, minus the shipping charges.

What is the right bike size for me?
Dynamic Bicycles come in multiple frame sizes to accommodate riders of different heights. Frame sizes are based on the length of the seat tube – measured from the center of the bottom bracket (where the pedal crank attaches to the bike) to the top of the seat tube. All of the other dimensions of the bike are proportioned based on this measurement, ensuring that the rest of the bike will be properly proportioned for your body size. For more information, see our Bike Sizing Guide or review our Frame Geometry Chart.

How does Dynamic Bicycles package and ship its bikes?
When you receive the bicycle, it is 90% assembled in its shipping carton. All you need to do is attach the front wheel, handlebar, seat, pedals, and any accessories. Average assembly takes less than 20 minutes. Dynamic Bicycles ships all of its bicycles by UPS Ground. All shipments are insured and require a signature for delivery confirmation. Shipping times within the continental US are between 2 and 5 days. The package weighs approximately 35 pounds and measures 52"L x 9" W x 30" H.

What assembly is required when I receive the bike?
Our bikes are 90% assembled in the box. Final assembly takes about 20-30 minutes. When you receive the bike, you will need to attach the pedals, attach the handlebar to the stem (handlebar already has brakes and shifter attached), insert the seat post (quick release lever) and attach the front wheel (quick release lever). Once this is done, you just need to put air in the tires. Setting up the bike is a great way to admire and get familiar with your new bike. The only tools required for setup will be a 15mm wrench (or adjustable wrench), 4mm, 5mm and 6mm Allen wrenches, and a pump for the tires. For assembly instructions, click on either the Hybrid-Comfort Assembly Instructions or the Mountain-Road Assembly Instructions.

How are Dynamic Bicycles guaranteed?
Dynamic Bicycles come with our 100% satisfaction guarantee. If for any reason within the first 30 days you own the bike, if you are not satisfied and we are not able to address your concern, you can return the bicycle for a complete refund minus shipping charges. In addition, we warranty the shaft drive for 2 years, lifetime warranty on the frame, the rear hub for 2 years, and all other parts for 1 year.

Care and Maintenance

What maintenance is required for the shaft drive and internal gears?
With our shaft drive, the only maintenance required is grease added to the front and rear gearboxes on a periodic basis - typically every 600-1000 miles. The frequency of this lubrication will depend on the amount and type of riding you do. More aggressive riders and heavier riders may need to add grease every 1-3 months, while more recreational or occasional riders may only need to add grease every 6-12 months. Grease is added to the front gearbox through a standard grease nipple (zerk fitting) on the underside of the gearbox using a grease gun. Grease is added to the rear gearbox simply by removing the rear plastic dust cover and applying grease right to the gear teeth. Typically, greasing the shaft drive takes less than 1 minute each time -- without getting grease on your hands or clothes. For best performance, we recommend Finish Line Synthetic grease with Teflon (tan color) which is available in most local bike shops. We also sell this grease as part of our Grease Gun Kit. You might also have good success with Park Tool Polylube 1000 or similar greases.

The Shimano internal gear hub is sealed and lifetime lubricated. It does not have a maintenance schedule. However, we recommend you periodically check the gear alignment (from cable stretching). See the instructions below for adjusting your gears at home without any tools.

What happens if I have problem with the shaft drive?
The shaft drive is likely the most durable component on the bike. However, if you believe there is a problem with your shaft drive, call us first. If we cannot help you readily correct it over the phone, we can offer you repair or replacement parts. The shaft drive is covered with a full replacement warranty for two years. After this period, a replacement shaft costs $89.95 - which is often times less than the cost of chain components such as a derailleur, crankset or rear cassette. Plus, the shaft drive can be replaced by non-mechanics in about 30 minutes with just two tools (a crank puller and an Allen wrench).

Where can I get the bike serviced if needed?
Our bikes can be serviced at any reputable bike shop. Aside from the shaft drive, every component on our bike is industry standard - from the brakes, tires, spokes, rims, seat and handlebar to the Shimano internal gear hub. So if you ever need service done such as brake adjustments, repairing flat tires or adding accessories, rest assured you can go to your local bike shop for help. As far as the shaft drive, this unit does not require adjustments or tune-ups of any kind, and is made of high grade components designed to last for many, many years. The shaft drive only requires grease to be added to the shaft drive periodically.

How do you remove the rear wheel if you get a flat tire?
In many ways, changing a flat tire on our chainless bikes is easier than it is on a chain bicycle. You simply remove the black dust cover from the rear gearbox and loosen the axle nuts on both sides of the rear wheel. The wheel slides straight off the back of the bike. You disconnect the shifter cable (quick-pull lever) and the wheel is completely free of the bike. To put the wheel back on, you reverse this process; re-attach the shifter cable, and slide the wheel right onto the bike. The washer on the shaft drive side is keyed so it only goes on one way - this ensures that when you tighten the axle nuts, the gears and wheel are aligned. No special tools or skills are needed.

For complete instructions for changing a rear wheel or repairing a flat tire on our bikes, you can download our instructions for Removing the Rear Wheel. Removing and re-attaching the rear wheel takes less than 1 minute.

What if the gears are slipping - how can you adjust the gears?
Shimano hubs are designed to be adjusted without tools and without needing to touch the hub itself. This makes adjustments fast and simple. If the gears feel like they are slipping or not shifting smoothly, this is usually due to a stretching of the shifter cable, which is normal (same as with brake cables). To re-align the gears, you use the barrel adjuster on the handlebar where the cable connects to the shifter to tighten to the cable and compensate for this cable stretching.

For complete instructions on using the barrel adjuster to adjust your gears, you can view our instructions for Gear Adjustment. Gear adjustments take less than 1 minute.

How do I adjust the brakes?
Most of Dynamic Bicycles bikes come standard withhigh quality linear-pull brakes (sometimes called V-brakes). These style of brakes are standard across the bicycle industry because they provide excellent stopping power and are easy to maintain. Linear-pull brakes work using independent brakes arms on either side of the rim of the wheel. When the brake lever is squeezed, the brake pads on each side of the wheel squeeze against the rim together to stop the wheel. If the brake pads are not squeezing evenly or if one pad needs to be adjusted, you can do this yourself using a screwdriver in just a few minutes. For complete instructions on brake adjustment, you can download our instructions for Adjusting Brakes.

Many of our bikes now also come with disc brakes standard or as an option. Some of our models are available with front disc brake, rear disc brake or both (dual disc brake). Disc brakes are intended to provide improved stopping performance in wet, icy and muddy/slick conditions. Disc brakes work much like brakes on your car, using a stainless steel rotor attached to the wheel and a caliper with metallic/ceramic brake pads that squeeze onto this rotor to stop the wheel. See bike model specifications to see if disc brakes are available on the model you have chosen.

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