Speed on an entry level tandem

Google sponsored links

godspiral

The BikeForums Team

-adv-

This is an archived thread, you can find the full version of this thread, with images, links and more content here.

Ready to buy? Check out these two online bike stores:
- http://www.nashbar.com (you can find the latest bike nashbar coupons in this thread)
- http://www.performancebike.com (you can find the latest performance bike coupons in this thread)

Cya on the forums,
- The BikeForums Team
- http://www.bikeforums.net

stapfam

This tandem looks interesting to me,

http://www.aibq.com/belize/indexen.html

though I'm unsure if/where it could carry 20-30 lbs of gear. THe geometry and fat tires should be comfortable.

I also hear that tandems can be very fast. This site shows a "racing tandem" going faster than I could ride alone even if the wife would contribute fairly little power.

I'm wondering if real world results match when different riders are contributing different output. Would an entry level tandem come close to the speed levels of racing tandems in the flats? Say if captain put in 150 watts and stoker 75 watts? What if it was closer to 120watts and 50watts?

Are high end tandems vs entry level have less performance level difference than high end road bike vs entry level because there is a lot more power input in tandem riding?

This is an entry level Tandem that will not do much for your tandemming "career". It will be heavy- Components are heavy and will either be well overweight or not have much durability and the Forks will be like a pogo stick.

Not the ideal entry tandem unless you just want to see what tamdemming is about and if you still enjoy it after a ride on this bike- Then you are a tandemming nut.

You may be able to tell that I do not recommend this bike at all. If you want to see what tandem riding is about- Hire one for a morning or afternoon. A couple of hours will soon tell you if the pair of you can get on with this diffent type of riding. It is not for every one. But for those that do enjoy 4 leg riding- it is the only way to travel.

godspiral

I'm actually more worried about the stoker, but the tandem in the link should be fairly comfortable actually:

It has huge tires, and has 3 connections to the back axle, and is all steel. I assume the longer the wheelbase, the more comfortable, and so expect it to be more comfortable than the equivalent geometry road bike?

I'm not too worried about my hands... I'd swap in a trekking bar, and maybe get better gloves if need be.

On flatland, would this heavy tandem go faster or easier than high end single roadbikes? -- the science sites imply it would in theory, but it or I can be making impractical assumptions. The site also gives the impression that climbing on a tandem is comparable to what it would be on individual bikes.

TandemGeek

I also hear that tandems can be very fast. This site shows a "racing tandem" going faster than I could ride alone even if the wife would contribute fairly little power.... I'm wondering if real world results match when different riders are contributing different output. Would an entry level tandem come close to the speed levels of racing tandems in the flats? Say if captain put in 150 watts and stoker 75 watts? What if it was closer to 120watts and 50watts?

On flatland, would this heavy tandem go faster or easier than high end single roadbikes? -- the science sites imply it would in theory, but it or I can be making impractical assumptions. The site also gives the impression that climbing on a tandem is comparable to what it would be on individual bikes.

From a previous response to a similar question...

All things being equal except for the bike, (and despite myths to the contrary) a tandem road bike with two riders is between 30% to 50% less aerodynamic than a solo rider on a road bike. Therefore, in order for a tandem to maintain a constant speed that is as fast (or faster) than a solo rider, the team must produce a net power output that is at least 30% to 50% greater than a solo rider.

Moreover, consider if you will that power production on a tandem is not necessarily linear since either one or both of the two riders on a given team may at any given time fall victim to poor form, individually or collectively. Put another way, even if you have two strong cyclists (1+1), they will lose some efficiency due to the nature of a tandem and, if they are not able to work well together, their efficiency will fall way off. So, in reality what you will often times find with a tandem is that you have two riders of different abilities who can produce variable levels of output which may or may not be as high as they are able to produce when riding alone. This is why some tandem teams who are weaker riders individually than a team comprised of two strong riders are often times as fast (or faster) than the stronger couple when both teams ride their tandems. The place where a team's combined efficiency level is most obvious is when they get to the hills where you have the same math problem with percent grade being substituted for headwind MPH and the added factor of team weight having more importance than aerodynamic drag. Less I digress...

So, to answer your question, if you have a team who can produce at least 30% to 50% more power as a team on a tandem they should be able to keep up with a solo rider. However, if a tandem team can produce a net power output above what is required to compensate for increased drag, the tandem pulls the train.

Are high end tandems vs entry level have less performance level difference than high end road bike vs entry level because there is a lot more power input in tandem riding?

No, it's quite the reverse if, by performance, you're referring to the strength-to-weight-ratio of the frame and components. Low-end tandems use heavy straight gauge chromoly tubesets which, despite their weight, still tend to deflect quite a bit when two riders place heavy demands on a frame: loaded touring, aggressive riding, or simply from their combined body mass. The more expensive frames use more exotic and/or custom drawn high strength / lightweight tubing of varying diameters, thickness, and shapes to optimize frame stiffness in the critical planes. Because tandems are such low-volume machines, these high-end machines are nearly one-off creations... most all of which are produced in small runs or one-at-a-time. Thus, the economies of scale that high-end single bikes enjoy -- as well as the amortization of the non-recurring design work and set-up costs -- are lost on these machines. So, at the end of the day, you get a lot of bang for your buck with a high-end tandem when compared to single bikes. In fact, my assessment is that your average entry-level tandem is almost double the cost of an equivalent single bike, and this holds true through the mid-range. However, as you get to the very high-end tandems, the ratio seems to shift as high-end single bikes have gotten obscenely expensive of late. The latter may be primarily a function of the component and integrated wheelset costs but, more times that not, even the frame-only prices of many high-end single racing bikes approaches the price of the very best mid- to high- end tandem framesets.

zonatandem

This is a typical cheaply made in China tandem. Being built under all sorts of names/labels. You can buy Micargi, Kent, etc for less, if price is your only criteria. Shipping costs are more than what the Chinese manufacturing cost is for that tandem.
You are the motors: test ride that tandem, then test ride a quality tandem. Any difference?
Having said that, you know what you want, you know what you can afford.
Its sorta tough to compare a Volkswagen Beetle or old Yugo car to a Vette or Masseratti; same for tandems.
However, have seen a young fella on a Schwinn Continental beat an old fella on a Cinelli, years ago. Not a good comparison either.
Quality lasts . . . junk ends up in the junkyard.

godspiral

Thanks very much for the clear explanation of power.

From a previous response to a similar question...

Put another way, even if you have two strong cyclists (1+1), they will lose some efficiency due to the nature of a tandem and, if they are not able to work well together, their efficiency will fall way off. So, in reality what you will often times find with a tandem is that you have two riders of different abilities who can produce variable levels of output which may or may not be as high as they are able to produce when riding alone.

Is "work together" a euphemism for putting out equal power? Is the 130%-150% total higher if both riders aren close to 65%-75%? Or does working together refer to something more subtle? I think I remember seeing a tandem "crank marketing feature" in a higher end model that allowed for compensation between rider output.

No, it's quite the reverse if, by performance, you're referring to the strength-to-weight-ratio of the frame and components. Low-end tandems use heavy straight gauge chromoly tubesets which, despite their weight, still tend to deflect quite a bit when two riders place heavy demands on a frame: loaded touring, aggressive riding, or simply from their combined body mass.

I measure performance in speed, range (comfort), and hill climbing. Lack of stiffness can have its compensating advantages in ride plushness. Heavyness tends to give you both. I'm sure I can appreciate the improved quality of a ride $1000+ more expensive, but we simply don't have usage plans to justify getting one.

TandemGeek

Is "work together" a euphemism for putting out equal power? Is the 130%-150% total higher if both riders aren close to 65%-75%? Or does working together refer to something more subtle? I think I remember seeing a tandem "crank marketing feature" in a higher end model that allowed for compensation between rider output..

Working together implies making compromises that ensure a team isn't working against each other. For example, if a captain tries to spin a cadence of 100 with a stoker who can't sustain revs much above 90, there's a good chance that the captain will encounter additional resistance from the stoker, reducing the captain's net output to the rear wheel. There are a variety of other ways that a team can work against itself -- from riding style, to athletic abilities, to personalities -- any of which can reduce the team's potential net power output.

I measure performance in speed, range (comfort), and hill climbing. Lack of stiffness can have its compensating advantages in ride plushness. Heavyness tends to give you both.

There are no advantages to a lack of stiffness in a tandem beyond a certain point... and that point is where "whippy-ness" begins to affect the steering and increases the captain's task load. Plushness is a function that can be better controlled through attention to wheel construction (rim, spoke count, lacing decisions), tire selection, and psi settings that can be "tuned" to meet different riding needs, vs. frame compliance which can't be easily changed. As for weight = stiffness, it's been said that you could drive over a Schwinn Varsity without bending the frame... Having ridden one for a few years before discovering truly lightweight racing and touring bikes, I can believe it. However, in retrospect the ride characteristics were awful. That said, I can recall from years ago getting dropped on my Raliegh Prestige by some kid on a beat up Varsity along the Santa Ana River Trail so, at the end of the day, it's all about the engine(s); a better bike will only compliment a team's abilities.. not make up for their shortcomings.

Bottom Line: By all means, if you're in the market for a tandem stay within your budget. While the higher-end tandems can deliver a more refined ride, far more reliable component performance and durability, and retain their value, some of the economical tandems on the market are as good as many of the Schwinn, Columbia, Western Flyer, and Colson tandems produced in years gone by. However, just set realistic expectations for the fit, finish, and quality of what you get for a given price point.

ElRey

At the power outputs you describe, you're going to be setting a casual pace. I don't really think the fine pooints of your query will, therefore, be of real significance.

godspiral

At the power outputs you describe, you're going to be setting a casual pace. I don't really think the fine pooints of your query will, therefore, be of real significance.

You're right. We would not be setting any speed records. Fast bikes tend to be easy to keep at 20-25kph for a long time... and it looks like on a tandem we could do 35kph. Finishline acceleration and ultrafast shifting are definitely not priorities. Unfortunately for us, rustproofing might be :(

CLRing off rust, then oiling and lubing over rust can usually provide a rideable bike if the gears and chain have little mileage. How many seasons can a steel dept store drivetrain last with little mileage if it rusts every winter?

godspiral

Working together implies making compromises that ensure a team isn't working against each other. For example, if a captain tries to spin a cadence of 100 with a stoker who can't sustain revs much above 90, there's a good chance that the captain will encounter additional resistance from the stoker, reducing the captain's net output to the rear wheel.

The gears are not independent for each rider? rather if a gear needs 30lbs of pressure to spin at 80rpm, then if captain puts in 20lbs and stoker 10lbs, and both can handle 80 rpms, then they are working together and the bike purrs along?

I notice from bike specs that the crank/cassette sizes are the same as touring bikes. Does that mean tandems have the same top speed as road bikes based on max RPMs at the highest gear ratio?

48x13 would max out at 30mph going 105rpm, just like a roadbike?

TandemGeek

The gears are not independent for each rider?

That is correct. With the exception of two or three very specialized designs, all tandems use a fixed timing (aka, sync) chain to connect the front and rear riders such that the captain's and stoker's cranks always turn at the same RPM. The timing chain transmits the captain's input power at the crank (and only the captain's power) to the rear cranks where it is (hopefully) combined with the stoker's power at the crank and transmitted to the rear axle via the drive chain. Thus, when the captain stops pedalling the stoker stops pedalling and visa-versa. When the rear chain is abruptly shifted, jumps or slips the "jolt" if felt by both the captain and stoker (who is usually more surprised than the captain as they don't have the benefit of knowning exactly when the shifter was being moved). This then is the reason why folks who are knew to tandems are coached to "over-communicate" what they are doing, to include telling the stoker when you are about to coast or shift gears.

There are two different systems available that allow for the captain and stoker to coast / pedal independently from one another, but they are essentially jack-shaft systems that merely permit disengagement of one rider's cranks from the final driveline; RPM under load remains the same. One was developed by Advanced Transporation Products (ATP) called the "Independent Pedalling System" (IPS) who has since gone out of business and sold the patent to QBP or some other third party producer that still produces the IPS. The other is the "Independent Coasting System (ICS) developed by da Vinci Designs in Colorado.

The Bilenky Viewpoint and Angletech Harmony semi-recumbent tandems (upright rear captain with recumbent front stoker) offer an optional dual drive system that incorporates a second gear cluster and derailleur between the stoker and the captain that truly does allow for independent cadence / variable resistance, but that's about the only production tandem to do so.

I notice from bike specs that the crank/cassette sizes are the same as touring bikes. Does that mean tandems have the same top speed as road bikes based on max RPMs at the highest gear ratio?

All other things being equal, a tandem fitted with the same size chain rings and rear cassettes as a single seat touring or racing bike will have the same gear ratios / inches / spin-out speeds, assuming both riders can spin the same max RPM. However, it is not uncommon to find tandems sometimes fitted with larger chain rings to take advantage of their higher combined power output, e.g., we run 54t x 44t x 30t rings with a 12x27t or 11x32t cassette.

Rincewind8

CLRing off rust, then oiling and lubing over rust can usually provide a rideable bike if the gears and chain have little mileage. How many seasons can a steel dept store drivetrain last with little mileage if it rusts every winter?
I don't think it will last long, if it rusts every winter. Besides, the efficiancy of the drivetrain will suffer as well. On a tandem the components are usually under quite a bit more load/stress than on a single bike. I wouldn't trust rusty components, especially on a tandem.

rjberner

How many seasons can a steel dept store drivetrain last with little mileage if it rusts every winter?

I hope this thread isn't a joke....... but I guess it doesn't really matter in the end........

In my heretofore limited experience with a tandem and almost constant "maintenance", tweaking, and inspection to keep our high end componetry up to snuff, I would have to say that if you ride this "tandem" as hard as you think you will, you won't have to worry about rust. Stuff will fall off the bike nicely, long before winter sets in.

If this is for occasional ice cream rides, then maybe you'll have a chance. Tandems are perfect examples of why the old saying "Buy cheap / buy twice" was coined. Just be forewarned my friend.

zonatandem

Independent coasting/pedaling systems will add lots $$ to the price of a tandem; from the sounds of your posting you are more worried about the technical aspects with a cheap tandem than with longevity; tandeming has a great 'fun factor', so quit worrying, buy that tandem and see how you two get along!
We've had all our custom tandems last well over 50,000 miles of riding TWOgether.
Quality lasts . . .

CBBaron

My solution to an entry level tandem with a non cyclist stoker was a cruiser with 3-speed hub gear. The one we got is an Al framed Fuji. Its definately not fast and fairly heavy but it is comfortable for shorter rides and the simplicity of the design makes for alot more durable components.
If you want to put a number of miles on an entry level MTB style tandem I would at least upgrade to something the level of a Burley Zydeco or Trek T900.
Craig

godspiral

Thanks very much for your patient and clear response.

The Bilenky Viewpoint and Angletech Harmony semi-recumbent tandems (upright rear captain with recumbent front stoker) offer an optional dual drive system that incorporates a second gear cluster

That is such a fantastic design for those 2 bikes. I'd pick mtb components instead though. Has anyone found a framebuilder to make a frame for them as a way to get what they want more affordably?

godspiral

I don't think it will last long, if it rusts every winter. Besides, the efficiancy of the drivetrain will suffer as well. On a tandem the components are usually under quite a bit more load/stress than on a single bike. I wouldn't trust rusty components, especially on a tandem.

Quite true. There's the weight of 2 people pushing down on the chain. Most components are alloy these days, and I'm assuming modern 7-8 speed cassettes have some useful plating. If the chain rusts out, its pretty affordable to replace. The cassettes aren't so bad either.

ElRey

dude, you're not going to average 35kph on a tandem with the power figures you posted.

zonatandem

godspiral:
"Affordably" and custom frame cannot be spoken in the same breath!

godspiral

godspiral:
"Affordably" and custom frame cannot be spoken in the same breath!

I guess "welding help" would be a more accurate phrase then.

mrfish

Another opinion:

If you buy a supermarket bike like the one in the ad above and use it to go to the shops, it's fine and will last for probably 10 years if you perform basic maintenance, keep it in the garage and don't ride in the wet. It's basically fit for purpose. New from the shop on flat ground it will only be marginally slower than a mid range tandem. Up hills (shifting and weight), down hills and round corners (handling, braking) it will be a lot slower than a mid range tandem because the components, wheels and frame are not as good.

Although the base model is fine initially, you will find that the adjustments are required more frequently if you ride it intensively. As soon as you want to do a bit more than ride to the shops little things will start to go wrong, e.g. the wheel bearings will go loose, a rainstorm will wash away the grease from the unsealed bottom brackets and hubs, the wheels go out of true.... While these things are not terminal in themselves and easy to fix, the little niggling things quickly add up unless fixed or the bike becomes no longer rideable and the rider gives up.

You thus need to spend a critical amount to get a bike that will withstand regular riding. For a single bike, regularly rideable bikes start at about £3-400 in the UK. For a tandem you need to be buying about the same level of components as the single bike, which probably works out at around £1000. Key differentiator is sealed bearings on the b/bs, hubs and headsets and a major parts all coming from a Shimano groupset. To revive the eternal debate, Campagnolo stuff lasts longer but costs a bit more. Advantage of spending the money is that the £400 bike will be worth about £250-300 for a long time if you decide you don't like it, while the £200 bike will be very quickly be worth less than £50.

An example of this was when I went on a 2 week tour in France with a group of non-cyclists. A girl on a very cheap bike required a new front wheel when the flange split, then the rear wheel spokes would not stay tight, and other numerous minor repairs were required every day to keep her going. She probably spent about £100 on repairs and I don't think she enjoyed the tour as a result. The 20 other other £300+ bikes probably spent £50 in total on inner tubes.

Previous - Top - Next