Tandem Cycling - Tips for a first timers Trek T50?

My wife and I just bought a Trek T50 off craigslist today. We both have mountain bikes but don't ride at the same pace so we thought we'd try a used tandem for a while to see if we like it. We plan to stick to the state park which is wide hardpack (crush'n'run). I'm sure we'll also do a fair bit of pavement but I expect most of our miles to be hardpack and/or greenways for now.

The bike needs new tires, tread is ok but they're the original tires and look a bit weathered after 15yrs. We rode our first 6 or 7 miles on them today but they're old and don't inspire much confidence after reading about some of the tandem crashes here. Any tips on replacement tires without spending too much? Stock was 700x38, it looks like we can take a slightly wider tire up front and maybe in the rear too hopefully.

Any other suggestions on other toys to order beyond a couple tubes and set of tires? We'll also probably pickup a rear rack and trunk bag.

The original owner also changed the sync on the cranks, the stoker's cranks are flat (on-the-pegs) when the captain cranks are vertical. I assume this is probably a poor way to start and we should re-sync them to be in the same postions?

1) I'd put the cranks in-phase since you are both already cyclists. You will likely find standing together easier if the cranks are in-phase.

2) Start out by concentrating on having fun together rather than seeing how fast the bike can go.

3) 15yo tires are due to be replaced for sure.

3) Don't forget a pump.

4) If you are used to a camelback you might want to check if she feels comfortable having you that much closer to her. Otherwise get used to drinking out of water bottles again.

Welcome, post some pictures.

Bontager 700c x 38 is what our Trek T100 came with. We rode gravel roads well and also pavement. Our team weight is 310 lbs (yours?). Now we run Schwalbe Marathon Racer 26x1.5 (different bike now but similar tire, not too wide, little tread). Choose a tire with high pressure rating.

If you want to do pavement as well and you don't get too technical on the trails, a 38 tire without much tread will be a good all purpose tire. Don't worry about the price of tires, you might spend $ 10-20 more for a better tire which will be on the bike for a couple of years at least, marginal cost per ride is insignificant, the costs of a blow out or flats are much higher. Tires are the second most important safety feature after helmets.

Measure your chains and replace if they are worn beyond tolerance.

I like to have a rack and a set of panniers, often go out with only one pannier mounted, but we take food, clothes, a thermos, whatever makes stoker happy, no back packs.


I like to have a rack and a set of panniers, often go out with only one pannier mounted, but we take food, clothes, a thermos, whatever makes stoker happy, no back packs.

We're about 295 as a team. We just ordered a pair of Kenda tires for now, a 700x42 for up front and a 700x38 for the rear.

A camelback was fine yesterday although I don't mind switching if my wife feels I should. We also ordered a rear rack & trunk bag, we may look into some panniers too if they're handier or we need the space.

Any tips on how to get the cranks in phase?


I keep a small pump in my Camelback, I guess I ought to break it out to see how easily it'll fill a 700x38 to 80psi...

We had our first flat today, only our 3rd ride but we expected as much with 15yr old tires. New ones are still in the mail and we'll replace both tires and tubes when they arrive.

http://evansnc.com/gallery/picKLE-cache/West_Side/Tandem/atandem1_320.JPG

Good lookin' tandem duo!
Suggestion on a pump: Topeak Mt. Blaster. Looks like a standard pump but with a hose that clips on top of pump. When utilizing the pump, a foot pad (to stand on with 1 foot) unfolds, handle flips to become a T-shaped handle and hose attaches to the valve stem. Pump away just like a floor pump! 'Almost' a pleasure to have a flat!
Enjoy the ride TWOgether!
Rudy and Kay/zonatandem

Any tips on how to get the cranks in phase?


The timing chain pops right off if you just push the chain at the point where it engages the chainring forcing it off one tooth and back-pedal the crank until the whole chain is disengaged. You pop it back on the same way by mounting it onto one chainring, engaging one tooth on the other chainring and back-pedaling, as you would mount a drive chain that has fallen off the chainrings. If somebody can pick up the bike and pedal forward rather than backwards you might find it easier. Getting the cranks in-phase involves doing this but eyeing the cranks to make sure they are parallel as the chain engages. None of this is too hard to do, but like everything it takes a little practice. No need to brake the chain with a chaintool.

The timing chain pops right off if you just push the chain at the point where it engages the chainring forcing it off one tooth and back-pedal the crank until the whole chain is disengaged. You pop it back on the same way...

Whoa! I would NEVER recommend doing that except as an absolute last resort. If the chain doesn't utilize a masterlink, (which would be the easiest way), if you don't know how to loosen your eccentric bottom bracket, (second easiest), and you don't have a chain tool, then take off a set of chainring bolts! Anything but trying to force a tight steel chain over the top of alloy chainrings!

And secondly, if the sync chain is adjusted correctly, you *shouldn't* be able to do that. It should only have 1/2 to 3/4" max play. Any more play and you're susceptible to having your sync chain drop off under duress.

Another way to get that "proper adjustment" is to drop your drive chain off and spin the cranks with the sync chain a little loose. Get the feel for that, then keep rotating the eccentric until you feel the cranks starting to bind, and back off a hair. That's all the "recommended specs" are trying to make you do ... leave just enough slack so you don't put a bind on the cranks, and that's all!

Any tips on how to get the cranks in phase?

Text book method: With the tandem held by the stoker's seat post in a work stand and the front wheel sitting on the ground....

1. Loosen your eccentric's wedge bolt assembly. The eccentric is the large, round aluminum cylinder that holds your front bottom bracket. Trek's eccentrics can sometimes be a bit finiky when it comes to loosening the wedge that holds the eccentric in place. If it isn't seized you should be able to back out the bolt that pulls the wedge up against the main body of the eccentric so that about 1/2" of the bolt head is exposed and then loosen the wedge by striking the head of the bolt with a plastic mallet to drive out the wedge. If that doesn't work... get back to me.

2. Once your eccentric is loose you should be able to rotate it in the eccentric shell. Rotating the BB and eccentric towards the front of the tandem will increase the tension on the sync (aka. timing) chain, whereas the opposite will make it go slack.

3. Rotate the eccentric to slacken the sync chain and then lift the chain off of the front timing ring so that it will rotate freely.

4. Working on the left side of the tandem, reposition the stoker's crank arm so that it is pointed down with the chain wrapped around the timing ring and then move the front crank so that the arm is pointed straight back towards the rear cranks... parallel with the tandem's boom tube.

5. With the front crank now at 3:00 o'clock (leading) and the stoker's crank at 6:00 o'clock (trailing), lift the sync chain back onto the front crank's timing ring's top most teeth and rotate the front crank counterclockwise to fully re-engage the sync chain with the front timing ring.

6. Rotate the front bottom bracket and eccentric assembly towards the front of the tandem to remove the slack in your sync chain, then check the crank arm positions to make sure they are still at a right angle to each other. If they aren't, rotate the eccentric to loosen the sync chain and reposition the chain on the front crank's timing ring as necessary to get the cranks at a right angle.

7. Once you are happy with the crank arm alignment with the eccentric rotated forward, spin the cranks a bit to make sure they don't bind due to non-concentric timing rings (a common problem) and then tighten the eccentric. Once the eccentric is tight spin the cranks again to make sure they don't bind or have excessive slack. Anything over an inch of chain deflection can be problematic.

8. Loosen and adjust the eccentric as needed to allow for a slight forward or rearward rotation of the eccentric to decrease or increase sync chain tension and then re-tighten. You're looking to achieve an average of 1/2" to 3/4" of chain deflection, measured at the top run of the sync chain by moving the chain up and down with your hands.

Next Chapter: Alternative methods and tricks.

Seriously, there are many different ways to get the sync chain off a tandem and they range from the text booth method to the one described by Xanti Andia, a method that I use myself under certain cirumstances by running my sync chain with 3/4" to 1" of slack, e.g., off-road riding and when playing around with crank phasing. However, to Onegun's point, if the sync chain is tight you really can mess up your timing ring teeth and run the risk of damaging your chain by forcing off and back on the timing rings. You can also remove one of the two timing side cranks in lieu of loosening the eccentric, a process made quite easy by self-extracting crank bolts commonly found on travel tandems. Yes, you can even remove the chain rings, assuming you can get to the bolts while the cranks are mounted: the latter is not something we can do with our daVinci cranks.

Regarding sync chain tension, the only really bad thing you can do is to have it way too loose... loose enough to self-derail at the rear timing ring on a hard bump or from chain sway, or to get looped by the crank arm also due to chain sway. Having a sync chain a little loose will only be problematic if you have a bent timing ring, are running disproportionately different widths of bottom brackets front and rear, or have a really flexy frame that bows under heavy pedal pressure. The latter is not a problem with your Trek as the frame is both heavy and stiff.

As for getting a sync chain too tight, I'm not sure you can do that by hand. While it's preferrable to have a little slack in the sync chain, the truth of the matter is... nothing puts more stress on a chain that it's actual use and once the captain begins to put a load on the sync chain, even one that seems too tight will still have a droopy lower chain run as the top run's links are all pulled tight under that load.

For more of the finer points... not to mention some pretty arcane stuff regarding sync chains and such, see the articles linked from this previous post: http://www.bikeforums.net/showpost.php?p=3896976&postcount=7

Text book method: With the tandem held by the stoker's seat post in a work stand and the front wheel sitting on the ground....

hehe! All good stuff, TG, but grab another cup of joe! :) He asked for directions on how to get his cranks IN phase, and you gave him directions for 90 out of phase!

Uhhh, you didn't by any chance just copy and paste your directions from one of the 1.2 million other posts you've written on the topic and forget to proofread it, did you? :D

He asked for directions on how to get his cranks IN phase, and you gave him directions for 90 out of phase!

Whoops...

That's what I get for checking in with the forum, writing the latest update on our Calfee, and watching the news all at the same time.

I guess I should have added a "don't try this at home" disclaimer or "don't force the crank if the chain is tight", or only pay homage to the guru's in this list, but in five years and two tandems I have not lost a tooth on my chainrings. I'll look out next time though.

I guess I should have added a "don't try this at home" disclaimer or "don't force the crank if the chain is tight", ....

FWIW, I didn't have any problem with your original instruction... noting again I tend to derail my sync chain as well. Moreover, I seriously doubt the OP could damage the chain rings on a Trek T-50, as they are surely far more stout and nick-resistant than the softer alloys sometimes used today.

In fact, Todd Shusterman of daVinci and I were talking a while back about chain rings and noted that, while some manufacturers hard-anodize their rings -- a good thing as it makes softer alloys more durable -- they do so before they machine the teeth. Therefore, any real benefit beyond the sometimes preferred aesthetics of having black or grey chain rings is eliminated as the part of the chain rings that wear are no longer protected by the hard-anodized finish. Go figure...

Anyway, forcing a sync chain off or on even by hand can nick or chip-off some of the material from these softer timing ring teeth if the sync chain is tight. However, a nicked timing ring tooth will only be problematic if any displaced material from the damaged tooth interferes with the seating of the chain... and even then, the chain will quickly knock down the high spots. To damage a chain would usually require the use of a lever, such as a screwdriver, to derail the a very tight chain.

Just a little more fodder....

On the other hand the job loosening the eccentric on a T50, if it is the same as the T100, is a bit cumbersome, involves a malet, and the right pegg to loosen the wedge bolt. I'd go with braking the chain if I chose not to derail, unless of course you need to anyway or you want to learn how these eccentrics work.

Thanks for all the replies. We rode 15 miles yesterday around town and my wife is becoming a big tandem fan now. I installed new tubes, tires, a rack & trunk bag, and computer last week and we'll probably order a set of grocery panniers soon too. I'm going to wait for a few more rides till I add on a set of clipless pedals.
Before I read the posts here, I found that i could pop the five bolts off the chainring to move the cranks in-phase. Probably a little more work than if I had read the directions here first...