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  1. #1
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    Tandem Tire and Frame Size Questions

    Hi,

    I've been doing a bit of research but had a question about tandem tires.

    I recently purchased an older Gitane road tandem. It is in nice shape, and rides fine. It has two old tires on the bike. The front is a 700 x 28c Schwinn record, showing cracking along the tire surface. The rear is a massive 35c specialized, with a max inflation pressure of 75psi, also showing cracks. The tires feel supple to my hands, but I'm guessing its time to get some new ones, right? My friend and I will be riding from Rochester to Ithaca, NY (95 miles) next week. If we put on new tires, should we carry ones of these as a spare tire with us?

    The fellow riding as the stoker has a set of Michelin tires he just bought from Nashbar on special. They are 25c, and I don't know the model, but should know by the end of the day, and can add to this thread later. While I've read from other posts here that 25c tires can be OK, are their any things I should be wary about in using 25c tires? We are a combined weight of just over 300 pounds, and will be carrying 1 bag with a lock, some shirts, tubes and minimal tools. One note is that the 40-spoke Mavic rims are relatively wide, compared to my newer 700c road rims. Should using 25c tires be alright? Should they fit?

    --

    The second question is regarding size. I typically ride a 57-58cm frame. The bike is a 23" in the front and 21" in the back. The stoker fits the rear just fine, but with the very short seatpost that came with the bike, I'm finding I'm a bit short on leg extension. Is it OK to have my seatpost raised relatively high (7 or 8 inches above the top tube) or will this have bad effects on geometry and handling?

    Thanks for the help - I've been riding bikes for quite some time, but I'm a newbie to tandem riding. It's been great so far.

  2. #2
    Super Moderator
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    I'd replace the tires as you don't want to have a tire fail on a tandem, esp the front.

    Without knowing the rim, it's hard to judge, but a wide rim with a narrow tire will make it easy to get pinch flats.

    If you buy wider than regular road tires (i.e. bigger than 23c) make sure you get the wider tubes too. 19-21c size tubes in 25-32c tires make for easier flats too (not sure why but after perhaps 15-20 attempts at saving weight by doing so I stopped).

    I haven't tried 25c tires on our tandem. It has 28c and it's fine so we haven't bothered with it. The two of us are probably 320-330 lbs, bike is about 40 loaded up. Personally I'm ready to relace the wheels with much narrower rims and experiment with 25s, but we have too much going on to worry about that.

    Raising seatpost should be fine as long as you have enough post in the frame to avoid the post or seat tube bending. Difficult to say without pictures. You may have to fiddle with the captain's stem too. Your position should be similar to that of your single bike.

    hope this helps,
    cdr

  3. #3
    Senior Member zonatandem's Avatar
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    There should be a mark on pilot seatpost that shows you how much of post MUST be in the seattube.
    If post is too short, buy a new/longer post.
    We have run 23 and 25mm tires for years and no problems. Before that (in the old days) we ran 27 x 1/8 or 27 x 1 1/4".
    Definitely put on new tires before your tandem toot to Ithica!
    Enjoy the ride TWOgether!
    Rudy and Kay/zonatandem

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