Yes there is a big advantage in controlling the stiffness of the frame. When you look at the simple math involved with stiffness, its a function of the materials modulus times the section modulus of the structure, or simply the modulus times a geometric function which is typically a cubic power. So a small increase in the geometry of the structure has a huge effect on the stiffness. This is why aluminum frames have oversized tubing. The oversized aluminum tubing is basically compensating for the low modulus of aluminum. With the composite materials we have more freedom to make the structure shapes which will enhance the stiffness. Its not limited to just a tube.

CAS is the only carbon frame builder putting all the cables inside the frame. It's a lot of extra work to put them internal, but it results in a more seeker frame, with improved aerodynamics.

CAS was taken back by the UCI ruling to ban non-traditional frames from UCI sanctioned competition. The UCI decided such frames had an unfair advantage and were too expensive for less developed countries. A rule is a rule, no matter how much we disagree with it. The ZR frame is legal for all non-UCI sanctioned events, such as USCF, and Triathlons. The UCI ruling has put many beam bike frame designs out of business, and /or off the market. To counter the beam type frame ban companies soon came out with ultra light bicycles, which the UCI later countered with a bicycle weight limit of 14 pounds.

The 55cm ZR frame weights about 3 to 3.5 pounds (1360 to 1588 grams) which is comparable with other available beam bike frame designs, as well as most steel competition frames. The frames are custom built using a patented process, which lends itself to a slightly heavier frame. However, the resulting frames are stiffer laterally and more aerodynamic, which overall gives the ZR an advantage.

CAS is a small company, which is mainly run as part time entity. You know the old saying, "I wouldn't give up the day job just yet". We only make a few frames per year, which are made purely for the passion of building such unique frames. Even though we're small we believe we have some leading edge technology to offer. We're the only company in the world with a patented carbon fiber tandem.

We're operating on a just in time basis with limited resources and only have raw materials in inventory. We have a number of steps to take to produce our patented frame, all of which takes time. A summary of the process is as follows: 1.) Determine the frame geometry design for the rider. 2.) Fabricate all 1st shell composite parts. 3.) Set up the jig and fit together the sections, run the internal tubing and bond the sections together. 4.) Prepare the 1st shell for the over wrap. 5.) Over wrap the 1st shell frame to the final thickness. 5.) Bond on addition features, chain hangers, and bottle holders. 6.) Prepare the frame for painting. 7.) Paint the frame with painted on graphics. 8.) Assembly the components, face the BB, build derailleur bracket, and install headsets. 9.) Final adjustments and a test spin. 10.) Package and ship. It is a long process to build a custom carbon fiber frame using our processing methods. Other companies have a more streamlined process, larger inventory, and non-custom bikes.

The frame has metal inserts as an integral design feature of the frame. In general any place on the frame which is in contact or attached to a metal part has a metal interface. The composite by itself is not durable enough for repeated bearing type loads. The dropouts are 6061-T6 machined aluminum. The head tube as chrome-moly 4130 tubular inserts. The bottom bracket is 6061-T6 machined aluminum. The seat tube now has a 6061-T6 aluminum inserts. The front derailleur has an aluminum insert which is threaded to accept the derailleur "braze on" bracket. The brake bridge is machined 6061-T6 aluminum.

The composite part of the frame is made of a 33 million-modulus carbon fiber called AS4, and the resin or matrix is an ambient curing two-part epoxy. We use both a cloth and uni-directional cloth, which we impregnate with the resin using a special impregnating machine we, designed. The composite lay-up is vacuum bag cured under ambient conditions. Ambient curing the composite has an inherent advantage of not having mismatched thermal coefficient stress induced into the structure.

Yes, dissimilar materials can form a type "battery" or an electrolysis process, which corrodes the base materials. Unfortunately carbon and just about any metal can have galvanic corrosion. Thanks to aerospace engineers this is not a big problem if the joints are designed properly to insulate the two materials from coming in contact with each other. All the carbon to metal joints on the ZR are insulated with an adhesive and glass fiber layer so that the materials are not in contact.

Yes, CAS has a US patent number 5,215,322 issued June 1, 1993. This patent covers the single and tandem frame geometry as well as the manufacturing process. So when we say the frame is unique, we have the united state patent trademark office to back up our statements. Not too many frame manufactures can actually make that claim. It's quite easy to look up this patent on the Internet if you'd like to learn more about it go to the U.S. patent trademark office website. (www.uspto.gov)

Sorry we're too small to offer sponsorships. We do offer discounts on the frames if your results resume warranties it.

We don't believe a color glossy catalog has any advantage over our website, other than you could read it on the pooper. We have opted not to purchase a hard copy catalog to keep our overhead cost low. We will be offering an on-line "word document" which will print out better than the website, for those that need a hard piece of paper.

We believe the ZR is very competitive, but we encourage you to shop around, because we want you to be happy with your purchase. As a point of reference we have the following competitors prices available, however none of them are custom carbon fiber. The ZR frames starting price is only $1,800.

No we don't we're just too small to afford that type of luxury.

No sorry we don't. We do not use any stickers or decals on the frames, like so many other companies. All the graphics, which you see on our frames, are part of the paint job. Its takes a lot of extra effort, but we believe it gives the paint job a true custom high-end look.

Well for one Trek is no long producing the airfoil. We are still offering an aerodynamic frame with equal to or better performance to the Airfoil. The ZR (55cm) and the airfoil (medium) both weight about the same in that 3 to 3.5 pound (1360 to 1588 grams) range.

The ZR has a 5-year warranty, which is pretty standard for the bicycle industry.

We stand by the frame we have designed and manufactured. The trouble is CAS has no control over the design and the performance of the components, which are installed on the frame. Further we have no control over how the user decides to use or abuse the bicycle. Cycling as much fun as it is, is an inherently dangerous activity if you are careless. There has been too much litigation these days crafted over numerous tangential issues. There will always be "stupid light" and components that have some type of problem; we just don't want to be held accountable for other company's mistakes.

The ZR and the ZXT are from the same family. In fact the same tooling is used to make either the tandem or the single bike. The ZR is basically the back half of the ZXT or the ZXT is an extended version of the ZR. We thought ahead when we developed the frame concept. Some day will make a quad, with the same tooling we have today.

We have been asked to look into to exporting our frames to a number of countries, but it just doesn't seem to work out financially. The shipping cost and import duties really add up, to where we think its cost prohibitive. No we haven't exported any of our frames. If you're considering this you may want to investigate the import taxes and duties for your country and possible shipping methods. We've kind of given up on the idea.

We have no local dealers or shops handling our products. CAS is web based. We answer our e-mails, and we answer all phone calls. Each bicycle we sell we provide detailed owners manual with it as well as all the manuals on the components. Most shops never provide the component manuals, so you'll never learn how to tune it yourself. We want you to take care of your own bike.

You can return any CAS product after 30 days upon receiving the product if you are not satisfied with it for any reason. All returns must be shipped freight prepaid after receiving a return authorization number. All returns will be subject to a 19% restocking fee. The merchandise has to be in the same condition that it was when it was shipped from CAS or no refund we be allowed. We will refund your purchased price minus the 19% restocking fee. No merchandise will be accepted after the 30-day period unless it is a warrantee return.

The ZXT frame weight is about 8 to 9 pounds (3629 to 4082 grams) for a 55cm/ 55cm tandem. There are lighter tandems available, but CAS has a different philosophy in regards to building a tandem. Some of these super light carbon frames weight in at a mer 6.5 pounds (2948 grams), but they carrier a rider weight limit of about 250 lbs (113.4 Kg) total. CAS has designed our frames to a higher total rider weight of 333 lbs (151 Kg) with a design safety factor of 1.5. We believe these design requirements are conservative, but then again nobody really knows what all the loads are on a tandem.

The carbon frame is designed using computer finite element analysis codes (FEA) such that front and rear BB don't have much displacement (or movement) between them by only using the main beam and the front bottom bracket's vertical member. For us it is easier to stiffen one member of the frame as opposed to adding additional parts, such as the "boom tube".

We tried the Magrua hydraulic rim brakes on the first tandem we made and just fell in love with them. The biggest advantage is on the long cable runs of a tandem. The hydraulic brake takes very little energy to operate the brakes. The Captains doesn't get as fatigued. The traditional steel cable can have a lot of friction due to the long cable run, when applying the brakes you constantly have to over come this friction by squeezing the brake levers. On long rides the captain expels enough energy keep the bike up right and out of trouble. The hydraulic brake is just much more efficient.

CAS is based in Utah and we have some pretty long steep climbs. We can easily reach speeds of 60 mph (97 kph) if you have to stop quickly at that speed, the standard brakes won't cut it. We also use it in conjunction with the hydraulic rim brake to slow your descent on twisty mountain roads, like a drag brake. The extra brake just makes the tandem that much safer to ride. In fact the when all the brakes are applied the tandem can stop like a single bike.

We have heard that Hayes is working on a road lever for disc brakes. The following is from an e-mail from Hayes regarding their development.

Hayes is currently working on a brake to work with road levers and cylco-cross bikes. The testing of the brakes on tandems has not been completed, therefore we do not approve the use of our brakes on tandems. Hayes doesn't have any information to send at this time. The brake is similar to the Hayes HMX-1 mechanical brake, but you will be able to use a road lever.

We just don't think it makes sense. A quick look at the math involved with putting single caliper road brakes on a tandem may make you understand. Lets look at it in simple terms of kinetic energy. KE = 1/2 MV². Where M = mass and V = velocity. In order to stop a bike the brakes have to expel energy about equal to the kinetic energy. An average rider weights 175 lbs (79 kg), and the bike 19 lbs (8.6 kg) or 194 lbs (88 kg) total. Let's say you are going 40 mph (58.7 ft/s)(64 kph, 17882 mmps). Your KE is equal to about 10,445 ft-lbs (14162 J). So your single bike calipers are rated to handle this energy, because your brakes work great. Now let's look at the tandem with the same brakes. Two riders at 175 lbs (79 kg) each and the lightweight tandem at 30 lbs (13.6 kg), this is 380 lbs (172 kg) total. Let's say you're going the same speed of 40 mph; this gives you a KE of 20,459 ft-lbs (27739 J). Wow that's only 196% above what the brakes normally operate.

For fun lets say you and your buddy are hamming down a busy street on your super light 96% inefficient braking system at 40 mph (64 kph). You are comfortably a car length behind a bus. Your captain looks at another car going by for 1/2 second, and mean while the bus stops. In the 1/2 second you went about 30 ft (9.1 M) and smacked into the back of the bus.

The example simply shows why CAS won't recommend single bike road brakes on a tandem.

We believe that the 1.125 inch diameter headset is strong enough for a road tandem. Additionally it is difficult to find 1.250 inch diameter headset, and stems. We simplified things and made both the ZR and ZXT the same size.

This is one of the reasons CAS got started. Back in the early 80's Mark Enders and his wife test road a Santana tandem for a couple of hours. Mark got tired of getting knocked in the back by this wife's head, and his wife wasn't too happy about it either. Later that summer Mark welded up a pretty funky looking tandem with lots of room for the stoker. CAS is producing frames with close to 30 inches (76.2 cm) of space from seat tube center to seat tube center. That's typically about 3 inches (7.6 cm) more than other tandems. We can add the extra length to the frame and still maintain the stiffness we want by just adding a few more plies of carbon to the lay-up.

No, our frame is not designed to accept S&S couplers

No, Sorry we just don't want to build these. We have enough fun with the road bikes.

There seems to be some activity in developing a tandem rated carbon fiber fork and its about time. CAS has a design for one, but we just haven't found the time to work on it. Wound-up has developed one with Co-Motion. We haven't tried it yet, but it looks like an oversize version of the road bike fork. It comes in either a single road bike caliper or a "V" brake canti-lever brake boss like their cyclo-cross fork. And in either a 1 inch diameter steel steerer tube suggested retail prices is $475 or a 1.125 inch diameter carbon steerer tube with a suggested retail price of $520, with 45 mm of rake. No weight was given.

Reynolds has developed a fork with Santana. Santana indicates that it is 1.5 lbs lighter than the traditional steel forks and has a 1.25 inch diameter headset. Suggested retail is $600. At the time of this writing neither Santana or Reynolds website seem to be working.

CAS makes its own stoker stem because we weren't satisfied with the performance of the stems commercially available. Our ZXT has a longer stoker "top tube" length than most tandems, which means we need a longer stoker stem with more adjustment than what is available. It gives you the ability to take a larger or small friend for a ride. Our stem can accommodate from a 48 cm to 56cm size "top tube" in the stoker position.

Another feature with our stoker stem is than it's made with square tubing. The square tubing takes the torque slippage problem out of the stem. On other tubular stems if you don't get the clamping screw super tight the stoker can twist the stokers handlebars quite easily and perhaps fall off the bike. We're surprised such a simple thing has been over looked for years.

CAS can make the rear spacing any size requested. We have settled in with the 145 mm spacing which is the standard for the tandem industry. The 160 mm spacing concept is great, but it's really difficult to find hubs and wheels in this configuration.

The ZXT is the only tandem in the world that is covered with an U.S. Patent number 5,215,322 issued June 1, 1993. You would see Santana coming out with a ZXT version of the tandem for the next 12 years when the patent expires. It's quite easy to look up this patent on the Internet if you'd like to learn more about it go to the U.S. patent trademark office website. (www.uspto.gov

Yes all the cables on the ZXT are routed internal in the frame. In fact the internal guide tubes are molded right in to the frame. The internal tubes are located just under neat the top part of the main beam and run the length of the beam. This routing keep the cables fairly straight for the entire length of the frame, aiding in reducing cable friction. Its a lot of extra work to build the tubes into the frame but we just really like the ascetics of not having the cables look like an after thought.

Yes we can accommodate that request, but we don't recommend it. It's not because we want to sell you the components, its because we want to make sure every component fits together and is operational. Our component pricing is competitive with tandem builders.

We prefer to assemble the ZXT here take it for tests ride them disassembles it for shipping. It's our last quality inspection. Some times we have to shim the hydraulic brakes and adjust the derailleur bracket to get them running smoothly. In the long run it's easier and faster if we do it here. Its not to say its real complicated to assemble a ZXT, it's just that it's a bit different.

We have no local dealers or shops handling our products. CAS is web based. We answer our e-mails, and we answer all phone calls. Each bicycle we sell we provide detailed owners manual with it as well as all the manuals on the components. Most shops never provide the component manuals, so you'll never learn how to tune it yourself. We want you to take care of your own bike.

Yes, it's possible. We don't recommend loading the frame with panniers, instead we recommend attaching a trailer to the left rear dropout or use a 'BOB" type trailer attachment. CAS has a special adapter, which inserts and attaches in the large hole in the rear drop out. A trailer can be hitched to this adapter.

Yes, they do. These are just really handy little things you got to have, so we put them on.

Yes, both frame types have them. The ZR only has room for one on the top part of main beam. The ZXT has 4 water bottle bosses. Two at the front position and two at the stoker position. On the tandem the bosses are located one on the top of the main beam and one on the bottom for both the front and rear.

No, they don't we use 145-mm the tandem industry standard. We know other tandem markers are doing this, but we have some good reasons not to. There are a couple of concerns and issues regarding a 160-mm spacing.

1st our drop outs are designed for the 140 or 145 mm spacing, so if we just move them from 145 to 160, it effectively rotates the flanges into a non parallel position where the wheel mounts. This would also skew the derailleur mount. The composite material or the stay with the dropout can not be bent to compensate for misalignment

2nd the stays on the ZXT are "fat" or wide as it is, about 1.0 inch. Moving them outward may cause the stoker to hit them with the rear of the foot during the circular pedal motion. Clarence now is about 1/4 inch with shoes pointed straight. There's a good possibility of hitting the stay.

3rd at 160-mm spacing the cogs or cassette are about 1/4 inch outboard of the normal chain line. To compensate for this type of chain line the wheel has to be further back from the BB to reduce the side load on the chain. Moving the wheel back would then (for the ZXT); increased stress on the stays, because of the longer lever arm.

There is no advantage to move the rear spacing out, when using a non dished Aerospoke wheel. The reason for going to the 160 spacing is to have a zero dish "spoke" wheel, and thus have equal strength on both sides of the wheel. The Aerospoke wheel has no dish; the spokes come straight out of the hub, perpendicular to the rim, and right in the center of the hub.