teachndad

Hi,

I just bought a Trek T200 off of Craigslist. I am pretty sure it’s in very good condition. It is from the early 90s. It has the original tires on it with some slight rust on the bolts. The main drive chain to the rear derailer had surface rust on it and it was dry as a bone. It had been sitting in the guys garage for a long time. It came with a kids stoker crankset as well and the chain that comes with it. I have some questions about it.

I am new to tandems pretty much. I had bought a beater tandem off of craigslist about 2 years ago, added new tires, a new rear axle and two new seats. We bought it for my 15 year old son who has balance issues and can’t ride a bike. We recently moved and the tandem was stolen at the new house while we were away. It was a standard heavy one with 26” knobby tires on it and bad brakes. Yet we had fun with it.

Several weeks ago, I started looking on Craigslist and found one in a garage sale ad. He was asking $375. I had a budget of $225 and that’s what I got it for. I told that the guy and he took my offer. I was wondering if I got a good deal. The crankset teeth show little wear. It came with lowrider front racks and a rear rack as well. Wheels are true.

I have several questions that I need advice on.

The tandem does not have a tensioner pully(if that’s what it’s called) on the chain that connects the captain to the stocker. It has an elliptical bottom bracket which I am not familiar with. How tight should the chain be and are the elliptical bottom brackets hard to work with? I rode it around the neighborhood with my 6 year old yesterday, and I had no problems with chain jumping off.

How tight should the chain be to the kid crankset. I pulled it up on the frame to as tight as I could get it and then tapped it down a bit to get a little movement in the chain. It didn’t rotate stiffly. So I think I got it right. Also, does the kid crankset have to be removed for an adult to ride it, or can I just remove the pedals? I am thinking no, because the crankset is rotating.

I mounted the kid crankset, but it didn’t sit directly above the stocker chainset (left side of bike). The kid crankset has a fat shaft that sits in a press. I loosened the shaft and moved it to the left until the chainring was just over the lower stoker crankset. Seems to me the pedals for the kid would then be no longer centered below the kid. My son didn’t seem to mind. I just wonder if I adjusted it right. Maybe it’s just supposed to be that way. If I center the shaft in the press, the offset from the lower stoker crankset is off by at least 3/8”. Moving it left got it much closer, but not exactly over it.

It came with curved racing handle bars and a handle bar stem that is too long for me. Does anyone know what the size of the shaft of the handlebar stem is? I want something shorter and also angled upward to give a more relaxed riding position. It came with bar end shifters which shift very nicely.

The tires came with presta valves. I have always used shraeder valves on my bikes, just because of the availability of pumps at gas stations if you need air. I wanted to switch to shraeder valved tubes, but that means I have to drill out the current valve stem hole. The rims are quite narrow. They are a sort of dark gray. Can I drill out the hole on this narrow rim? Is it cheaper just to get a good hand pump, or switch out to shraeder?

I wanted to go with a larger tire. I am thinking of a 700C x 38 or even 29er tire. But I think there might be some clearance issues with the frame with a 29er tire. I have never liked the narrow tires, because I always I believe it’s easier to get flats on the narrow tires than maybe a wider tire. I am not a weight weenie, btw.

We plan on just using the tandem for around the neighborhood and maybe putting it on the car and taking it to the beach for a short bike ride now and then.

Just some observations. The Trek handles so much more nimbly than the old beeter tandem I had. It’s much lighter and can be moved in and out of the garage with ease compared to the old one. It shifts so much more smoothly. Everything is Shimano Deore. Brakes are so much better as well. I am loving it.

Your thoughts?

Thanks.

TandemGeek

How tight should the chain be and are the elliptical bottom brackets hard to work with? From 1/2" to 3/4" of slack (up and down travel) is fine. Beyond that you run the risk of dropping the chain on bumps or aggressive out of the saddle riding. As for the eccentric, it depends on how 'stuck' it might be based on previous service and the time it's been sitting. The information at the following URL appears to have been lifted from a thread here at Bike Forums and it contains some tips / guidance that should help. https://www.luffman.us/gps/t100.htm

How tight should the chain be to the kid crankset. Also, does the kid crankset have to be removed for an adult to ride it. About 1/2" and, no... you can switch from kid to adult mode simply by removing the pedals from the cranks that aren't being used. Relative to your other questions on the kiddie crank installation, you get the chain line adjusted with a little trial and error. Ideally, the chain rings should be lined up and there are a number of ways to do that that minimize the off-center position of the cranks below the child's stoker. Mark Johnson has written an extensive primer on kiddie cranks that you can find here: https://www.precisiontandems.com/artkidbackinstall.htm

Does anyone know what the size of the shaft of the handlebar stem is? Best bet is to measure, but if memory serves the older Treks used a 1.25" threadless headset and 27.2mm seat posts.

Can I drill out the hole on this narrow rim? Is it cheaper just to get a good hand pump, or switch out to shraeder? Just how narrow is it? I'm guessing these are the original Trek house-branded "Matrix" rims. Again, common sense should give you a pretty good idea if there there's enough meat in the spoke bed to accommodate an enlarged hole... enlarged by using a ream or file not a drill bit. BTW, there are adapters that let you use a regular pump with Presta valves that don't cost more than a couple bucks: https://bicycletutor.com/presta-valve/

I wanted to go with a larger tire. I am thinking of a 700C x 38 or even 29er tire. Off hand, and because tire sizes vary so much from their label sizes, you'd need to measure the openings at the fork crown and rear stays to establish the maximum dimension of the tire opening and then compare that to the actual tires you're considering. Remember that if the rim bead is truly narrow on your Trek T200's Matrix rims, it may or may not work well with the size tires you're considering. Frankly, 32mm should be plenty wide and work just fine for riding on paved or hard-packed bike trails with what you have.

teachndad

Wow!

Thank you TandemGeek.

Excellent advice on all my questions. The links are very helpful. I especially appreciate the info on the Shrader adapter. Yes, the rims are the Matrix rims as you mentioned.

Fantastic.

Rod

moleman76

https://sheldonbrown.com/tire-sizing.html#width is a link to a matrix of suitable tire sizes for rim widths; rim widths measured inside the rim, so you would need to take a tire off (front wheel probably easier, if the rims are the same) to measure. There is pretty good clearance if you want to go with wide tires, but if you need wider rims, new wheels will cost you more than you've paid for the bike. As a point of reference, in 1994 the T200 had 28mm tires, the T100 35mm, and the T50 had 38mm; the latter two had a wider rim.

A reasonable floor pump, for inflating tires at home, will probably come able to handle either presta or schraeder. On the road, if you have a flat, you might not be near a service station! A size 4 Zefal HPX pump (might have to purchase from a discount source in Europe) should fit between the pegs on your T200. Some folks are fond of the Topeak Morph, puts out good pressure, has a hose for the connection to the valve.

I'd suspect a 1.25" threaded headset (versus the "modern" threadless variety).

The "Vintage Trek" site has information that may help you:
https://www.vintage-trek.com/model_numbers1.htm (way down, since model number starting with letters are given last) will help you figure out which year your bike is, based on the frame color)
https://www.vintage-trek.com/TrekBrochures.htm has brochures for the various model years

You got a good deal on that price!

teachndad

Thanks for the link to the presta adapter. I will go that route.

I measured the quill stem width with a tape measure and I came up with a 1 1/8 width at the top of the recessed allen head bolt on the top and also where the quill stem fits into the headset. That seems contrary to the feeling of the posters in this thread who felt it might be 1 1/4 width. I looked up the tandem by the color and it is the 1992 year model. There is a PDF of the technical details of the parts on one of the vintage Trek websites, but it's too small to see the size. Should I assume my measurements are correct at 1 1/8 even though, others feel it might be 1 1/4? When I measured it, it's definately not 1 1/4, that would appear to be too wide, even though I eyeballed it.

Thanks

Rod

TandemGeek

If the ID is 1.125" (1 1/8), then it's 1.125", hence the recommendation to measure. Being that it's a first year model and has a quill stem, it makes sense.