One of the great things about recumbent design is the fact that many different design set-ups can be made. Although the front wheel drive concept looks new, it can trace its origins back to the first wooden wheeled Velocipede bicycle. The same can be said about the compact long wheel base design. This design lay-out can trace its origins back to 1895 Challad Normal Bicyclette.
The point of this article is to point out the strong and weak points of each of these design types. I am looking at these designs from a commuters point of view. At least for myself, the commuter type bike is the best all around type of bicycle design for general use because of its greater visibility in traffic and overall usage when things need to be carried. Let s look at the two types.
Front wheel drive can come in many forms. There are ones using a fixed boom system and the chain bends as the front wheel is turned. Others use a pivoting front drive train section so the entire drive system turns. My test example uses the later type of drive train set-up. I like this type of design because it is one of the simpler ways around using standard bicycle parts without getting into a more complex pulley system. It's basically like taking the rear end of a bike and putting it on the steering part of the bike. This means the chain length is now much shorter.
Since a fork now graces the rear wheel, at least my bike has the option of using a standard bike roof rack or being placed in the back seat of the car when the rear wheel is removed. Since the front end turns, the bike can go into the car that much easier.
Because the bike is being used for commuting, the seat is set at a height of 23" above the ground. The bottom bracket height is 21" high, making it about level with the seat. The seat back angle is 57 degrees. All of this adds up to what some call the sprinters position. Much of your weight is placed on the seat base and after a while, your rear end can go to sleep. For the longest while, I thought that this was a problem so the 206 rear drive recumbent was built with a more layed back seat angle. Although the seat angle was thought not to be suitable for anything other then short commutes, a ride on a 100km long route proved otherwise.
The learning curve on a front wheel drive recumbent is a little longer than on a normal recumbent type. On a up-right type bike, you will counter balance yourself buy pushing and pulling on the handle bars when you pedal. You will do the same thing when you start out on a front wheel drive recumbent bike. The problem is that when you do this, you will pull the handle bar assembly in the opposite direction the you pedal the bike. On some types of FWD recumbents, the handle bar is designed in a way that it is fixed so this will not happen but my bike is not designed this way. You must learn to let your legs control both the steering and pedalling at the same time. Your arms are more of a guide to the steering then the principal steering aid. On tight turns, your legs more flexible than you might think so they are not a problem like you would think they are. The one handling point that you do notice is the slight side to side motion when you pedal. It s like riding a bike on rollers, it demands a very smooth cadence. If you have a heavy handed type pedalling style, this type of FWD may not suit you.
Since a 20" front wheel is used as the drive wheel, there is a limit on the high end side as far as gear ratios go. Since standard bike gears are used, a T52/42 chain ring in my case, combined with a 13 tooth high gear, the highest gear in gear inches is 80". This will put a limit on its upper speed range, but keeping in mind that this recumbent is a commuter bike, this is not a problem.
There are a number of problems that do come up with a FWD type bike. On steep hills, the weight transfer will go the rear wheel, giving less traction on the front wheel. When loose grave or sand is combined with a steep grade, you can lose all traction on the front wheel. Another problem comes up when some people with wrist and arm injurings like carpultunnel try to use a FWD type bike. Because the drive train and steering are combined, a form of steering tork is created so there is some pressure put on to the hands of the rider.
An overall view of a FWD system is that it is not for everyone. But for those with the taste for something different, it s an interesting alterative.
The compact long wheel base recumbent is one of the best overall general purpose bikes that I have ever ridden and is the test bike for this article. Without trying to repeat the same facts from the last article, heres a review of the compact long wheel base recumbent.
This type of recumbent is the most comfortable and easy handling bikes that I have ridden. Paved roads mean that the smaller tire size is not a big factor in overall ride quality. The long wheel base smooths out many of the roads small bumps. Although the bike s steerer tube angle is at a steep 55 degrees, there is a feeling of little steering flop at speed and the steering flop is only felt at low speed and at a stop.
The seat is set at a height of 26" and the bottom bracket is set at 23". The result is a more comfortable seating position then is on the front wheel drive set-up. You feel like you are sitting on top of the bike, not integrated into the bike like my FWD type or the rear wheel drive type that I built. Since the seat is so high, you are eye level with most types of vehicles up to mini vans and pick-up trucks.
Although the wheel base is 50.5" long, the overall length of this bike is only slightly longer than the FWD recumbent. Since the driving tire size for the bike is also 20", the same problem that affects the FWD as far as getting higher gear ratios. Although the chain is much longer, you tend to forget this fact after riding the bike for some time. This recumbent is also used as a commuter so I don t feel the gearing is a major problem and by wearing clothes suitable for cycling, the chain is not a problem.
Since the bottom bracket assembly is fixed in the frame, climbing on hills is very good. Since you are in a way, still pushing down on the pedals, the feel is something like a up-right type bike. Traction on climbs is no problem since the rear wheel is the drive wheel.
The compact long wheel base design lay-out is one of the types gaining popularity among the main stream recumbent builders. The short learning curve needed means that most people will not be put off riding a recumbent bike. My CLWB is the bike that I use for most of my short trips and for getting to work. A modified bike rack was made so this bike could carry my bike bags. If I where to have to pick just on recumbent bike for riding, this type would be my pick.
Both FWD and RWD have design advantages. FWD types gets rid of the lengthy chain and this aids in the storage of the bike. Although my FWD recumbent uses a fixed frame design, FWD does allow you to create a folding recumbent without the worries of dealing with the long chain. The CLWB has a very short learning curve and predictable handling in a design that takes up no more room then a up-right bike. Either can be made to work around your life style.