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Thread: Trek 720 1982

  1. #1
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    Trek 720 1982

    Hi,

    I just received my 1st vintage bike. It is a 1982 Trek 720. Yes, the one with the caliper brake. As I am learning the bike. I have a few questions hoping someone can help. I'm sure I will have more later.

    Here are what came with the bike:

    Shimano Deore triple crank, Deore XT FD/RD
    Shimano 600 brake & lever & downtube shifters
    Shimano Deore DX hub M650 front and rear with Mavic MA40 rims and 700c tires

    1. The rear spacing should be 130. I noticed the stays were pushed outward as the Deore hub is 135. Is the bad? Should I replace the rear wheel with 130 hub? What do you recommend?

    2. The brakes worked ok but it's gray color which I don't care too much. I might want to change them to older Suntour Superbe or Dia Comp. Is this a good idea?

    3. I also would like to change the drive system to Suntour Superbe or Cyclone OR to Shimano Ultegra with the 8 speed bar end shifter. Am I going the right direction?

    4. Does anyone know what I can use for touchup to match the color (teak?)

    Thanks a lot!

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    Large Member realestvin7's Avatar
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    That bike should not have come with 130 spacing. Upgrade it like a touring bike should be upgraded (sweet long cage derailleurs).

    What brakes are currently on it?
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    You are right. Trek changed the spacing from 120 to 126 in 1982 to accommodate 6-7 sprocket freewheel. So it is either 120 or 126.

    So it is even worse? Stretch from 120/126 to 135?

    The brake now is Shimano 600.

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    Senior Member randyjawa's Avatar
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    The stretch from 125mm to 130mm is acceptable but to stretch the drops another 5mm apart, to 135mm is just too much, in my opinion. You should replace the rear hub and fit a six speed freewheel to it.

    Changing brake calipers is not a big deal, provided the ones you install will reach the wheel rim braking surfaces properly. Ensure also that you get brakes that have the correct mounting system (hex head nut as opposed to socket head nut).

    Forget the eight speed transmission. The drop faces will not accommodate the eight speed properly. Stick with the six speed and seek out bar end shifters. Suntour Barcons are very nice, work great and will suit the bicycle just fine.

    You can take the bicycle to an automotive paint store and they will custom match the paint for you.

    All that said, you seem pretty new to the interest of vintage road bicycles. I publish a website, MY "TEN SPEEDS" with the intention of helping, like you, get a head start on the interest. A visit or two to my website just might end up saving you a good deal of cash, effort and frustration.

    I hope this has been a help and welcome to the Bicycle Forum, one of the best vintage bicycle information sources on the www.
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    Senior Member Road Fan's Avatar
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    The bike was built for 126 mm rear spacing. If the rear spacing is now 130 mm, it might not be a good idea to return it to 126. As a 130 you can put on any drivetrain 8-speed through 11-speed, as long as the hub is a 130 hub. I agree with Randy, going to 135 is not recommended, and you can get all the gear range you need with 130. If you ride road, the wheel strength will be adequate even with touring loads.

    If it was now 126, I'd say go for the 126, but I don't think it's your best move now.

    As far as the SunTour, I think it's a good direction, but there are many that you can take.

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    Senior Member sonatageek's Avatar
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    Interesting and that is what I would think, but I have a nicer 120mm spaced frame (531 throughout) and I contacted a local frame builder about re-spacing to 130mm. His response was no problem and the cost would be $20.

    I would not try such a large change on my own, but if the OP wants to go to 130mm, perhaps there is a local builder he could check with?

    Quote Originally Posted by randyjawa View Post
    The stretch from 125mm to 130mm is acceptable but to stretch the drops another 5mm apart, to 135mm is just too much, in my opinion. You should replace the rear hub and fit a six speed freewheel to it.
    .

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    DRF aka Thrifty Bill wrk101's Avatar
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    To me, the choice would be easy. 7 speed, 126mm spacing (double check the current spacing), Suntour Cyclone GT Generation 1 derailleurs with Suntour barcons. If your rear drops are already spread to 130mm, I would keep it at 130. Remove the wheel and check it, will take two minutes.

    That first generation Cyclone is my favorite group, and is still available at a reasonable cost if you are patient. Just picked up a set last week off ebay.

    A jump from 126 to 135 is doable, but should be done with a professional cold set. I have tried to squeeze in a 135 hub into 126 dropouts, it was not a good idea.... But with a cold set, you would be fine. I would not do it, that bike would be just fine with seven speed stuff.

    Touch up paint? Get a couple of colors of Testors enamel model paint (Hobby Lobby or similar), and a soda bottle cap, and custom mix your own. I do it all the time. Note, this is for minor touch up, a chip here and there, a scrape on the bottom side of the chain stays from a kickstand, and so on.
    Last edited by wrk101; 09-21-11 at 04:36 PM.

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    Senior Member ColonelJLloyd's Avatar
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    Quote Originally Posted by randyjawa View Post
    You should replace the rear hub and fit a six speed freewheel to it.
    So it's currently at 135mm (my guess is that it's not, but had a 135mm hub shoved between the dropouts) and you're suggesting to cold set it again to 126mm? What sense does that make?

    OP, your Trek 720 has long chain stays and if the spacing at rest is right around 130 you're golden. A 130mm road hub will let you run Shimano/SRAM compatible 7-10 speed cassettes. The Deore mechs will work famously in friction mode with some bar end shifters. You're on your way to having a nice setup.
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    Senior Member leaping_gnome's Avatar
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    About the brakes, and wheels too, Trek sized many of their early frames for 27" wheels instead of 700c. It will make a difference when you select a brake reach when replacing the calipers. I personally like the Suntour Superbe. They are very positive when used with Kool Stop salmon pads. The Superbes come in short and slightly longer reach so be aware when selecting. Since your hubs are probably not original (assuming the 130 spacing) then you probably do not have the original rims either, so probably 700c.

    Recently I met a fellow with a showroom stock immaculate 714 model from about 1981-1982. His bike was absolutely original and looked like it had just been set-up out of the box. I noticed that there was a large clearance between the front tire and the fork crown which made me realize that it had 700c wheels. There were drop bolts on both the front and back brake. My conclusion was that Trek had done that originally, perhaps as a 700c option. Your 720, being set-up for calipers, could be similar. Just saying, it's worth checking.

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    I am very new to vintage road bikes. Like I said, this is my first vintage bike. I have done fair amount of reading and hope to learn something from this bike.

    I guess the bike had 126 rear spacing originally. I am not sure if it had been stretched to 130, will have to measure it to confirm tonight when I get home. If it is 126 now, I 'd probably prefer to stay with it and build the bike with older parts with 6/7 freewheel.

    I noticed the Deore DX hub on the bike now has a few rings (5 or 6, look like spacers?) on the non-drive side of the hub. Is it possible to remove some of them and use the hub with a shorter QR before I find other hub or wheel so I don't keep stretching the bike? Is it okay to leave it like this if it is stretched from 126 to 135? I am looking at a set of vintage Phil Wood hubs to maybe build a set of decent wheels.

    According to some older posts here, 1982 (supposed to be 1st year they offered it) has 700c wheels and caliper brakes, but in 1983 and after, they changed to 27" wheels and cantilever brakes. So there are some confusions.

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    DRF aka Thrifty Bill wrk101's Avatar
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    My 1979 714, predecessor to the 720, came with 27 inch wheels.

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    Your 720 would have been spaced 126mm for a 6-speed cluster, and had Gran Compe centerpull brakes and 27" wheels. If you're planning on doing loaded touring you may well want more powerful brakes; Tektro makes several affordable dual-pivot models with various reaches so you could also convert it to 700C wheels as well. Later 720s had cantilever brakes and 700C wheels.

    Your Deore XT derailleurs and crank are fine, but original equipment would have been Huret Duopar and Sugino AT cranks (50-45-28 "half-step + granny").

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    Quote Originally Posted by JohnDThompson View Post
    Your 720 would have been spaced 126mm for a 6-speed cluster, and had Gran Compe centerpull brakes and 27" wheels. If you're planning on doing loaded touring you may well want more powerful brakes; Tektro makes several affordable dual-pivot models with various reaches so you could also convert it to 700C wheels as well. Later 720s had cantilever brakes and 700C wheels.
    IIRC the 700/27" wheel transition was the other way. While everyone was switching from 27" to 700C, Trek did the opposite on their touring frames. I used to have a 1983 with 27" wheels, now have a '82 frame.

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    I measured the rear spacing. It is 126mm rear spacing bike with a 135mm hub!

    Here is a picture of the hub spacers on the non-drive side of the hub I was talking about. There are two sets of spacer+washer total about 10mm. I think if I remove them and replace with a 126mm QR then it will be good. Right?

    DeoreDXHub10921.jpg

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    You will need to get a shorter axle or shorten the one you have. If you shorten the one you have, leave a nut inboard on the end you are going to cut (e.g. with a hacksaw). Calculate the required length to cut off by the difference in length of QRs, so in you case 9mm shorter. After you cut the end off, chamfer the cut end with a file or grinder, then unscrew the nut to clean off the threads.
    With the shorter axle, delete an equal length of spacers at each end and check the centering of the wheel in the frame; adjust if needed via the cones. Make sure you leave enough space on the drive side that the chain doesn't interfere with frame when on the small cog. Unlikely but possibly the wheel may need to be re-dished.
    If the threaded end of your existing QR has enough threaded length, you may be able to shorten it as needed also.
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    720's were sold both as a frameset and as a complete bike. Judging by the components you have on it now, yours was bought as a frameset. So I wouldn't worry about building it up as "original."

    I had Suntour Superbe brakes on mine for many years. They fit 27" wheels admirably, but when I switched to 700c I had to get a Campy drop-center bolt for the rear brake; the Superbe caliper would not reach the 700c rim. The front was fine, though.

    I'm not sure what the gray color of the brakes is, whether an anodized finish or a paint of some kind, but rest assured: removing it is easy. You'd want to disassemble the brakes completely and dunk the aluminum brake arms in the appropriate chemical, then polish with fine sandpaper and metal polish.

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    Old's'cool: I thought about doing what you said but with a few big ? I think I will try to find a wheel or a hub first, if no luck, will try this! Thanks for all the help!

    rhm: if I can find a set of superbe brakes the longer version with 49-59mm reach. Would those work with 700c wheels?

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