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  1. #1
    Senior Member chrisch's Avatar
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    Tire Sizing Trek 520

    Hi everyone!

    After completing a few tours this summer with my new '07 Trek 520, I'm giving thought to changing the tires to something with a better profile. Many here have recommended the Schwalbe Marathon Plus tire, but I'd like to better understand tire sizing before buying anything.

    I understand it's possible to replace the existing 700x32C Bontrangers with 700x32C, 700x35C, or even 700x38C(??) Schwalbes. That's fine and all, but is there an optimal choice, or does it come down to preference? If it is preference, how will the different sizes affect my ride?

    Thanks in advance! chris
    TrackMyTour.com - An iPhone app for Bike Touring! See who's touring now and where.

  2. #2
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    Wider tires=More Comfort for you. They soak up bumps in the road better and you don't feel as beaten up by the bike as you do with skinnier tires.

    Wider tires are also slower moving than skinnier ones, but if you're doing loaded touring, the speed difference really doesn't matter.

  3. #3
    Senior Member chrisch's Avatar
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    Quote Originally Posted by fat_bike_nut View Post
    Wider tires=More Comfort for you. They soak up bumps in the road better and you don't feel as beaten up by the bike as you do with skinnier tires.

    Wider tires are also slower moving than skinnier ones, but if you're doing loaded touring, the speed difference really doesn't matter.
    Hi fat_bike_nut, I think what confused me is the second number in the sizing. I realize it's the spacing between the beads, but only considered how well the tire would fit, and not how wide the tread would be. I think it makes sense now. Thanks.
    TrackMyTour.com - An iPhone app for Bike Touring! See who's touring now and where.

  4. #4
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    i'm biased in favor of the wider tires,
    a regular 37-622 Schwalbe marathon is a good choice.
    it's suggested max air pressure is 85 psi vs. 95 psi for the 32-622 size.
    IMO, the rolling resistance lost by decreased air pressure is only gained
    back by the slightly wider and narrow tire contact area. only speed loss
    is probably due to slightly slower acceleration of the heavier 37 mm size.
    plus there is a comfort gain that is hard to project, after a few hours on
    the road; lower transmitted shock is a nice benefit. the fatter tire is
    also less subject to flats from tracks, pot holes and other pavement suprises.

  5. #5
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    How did those bontragers work out for you? I just put mine back on, I haven't ridden them yet.

    I used the Conti Top Touring (may they rest in peace) and loved them, for most of my road touring. I also used the Conti Travel Contacts on my australia tour, b/c they have some side-knobs, and I wanted that for additional traction on gravel roads. I found them to be a bit on the heavy/slow side, but they performed fine.
    ...

  6. #6
    Year-round cyclist
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    I have year model 2000, which had a threaded headset (i.e. slightly different fork), but I believe the recent Treks 520s have about the same characteristics. If that's so:
    - you won't have problems using a 700x37 tire, maybe even a 700x42 tire on the rear wheel;
    - a 700x35-36 is about the largest size that fits on the front wheel if you use fenders. I once tried a Continental Top Touring 700x37 in front; the wheel could spin, but barely.
    Michel Gagnon
    Montréal (Québec, Canada)

  7. #7
    Senior Member chrisch's Avatar
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    Quote Originally Posted by valygrl View Post
    How did those bontragers work out for you? I just put mine back on, I haven't ridden them yet.
    I like them, although I have little to compare them to. My tours this summer were mostly on paved surfaces, which is fine for the Bontragers. A better profile would have been nice on some of the unpaved roads and paths. I'm thinking of a tour in Iceland some year, and I'll definitely need something more rugged for that. Perhaps even a bike with suspension?

    Let me know when you get out with the Bontragers. I'm curious what you think of them in comparison to the other tires you've used.
    TrackMyTour.com - An iPhone app for Bike Touring! See who's touring now and where.

  8. #8
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    Here is the thread on my Trek 520 with a picture of 700x38c Kenda Kwest tires and fenders mounted.

    They ride just fine. I will most likely be dropping to 700x28 or 700x32 tires though just to see what the difference feels like.

  9. #9
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    I put these on this spring. just now at the 400 mile mark (414 to be exact). They seem like good tires for less than $10. no loaded touring yet but I weigh around 240#. I still have the 32 racelites on the front

    http://www.performancebike.com/shop/...tegory_ID=5420

    a friend rides a trek 1000 and saw mine so he got a set similar but in a 28. He says they are better than the racelites that came on his trek. I dont know if I'd go that far but they are god for the price.

    http://www.performancebike.com/shop/...tegory_ID=5420

  10. #10
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    It's strictly a matter of personal preference. If you are comfort oriented, wider is better, and if you are performance oriented, narrower is better. Somewhere in between is where you want to be. But if you want my opinion, there's no advantage whatsoever in going wider than what you need for your weight.

  11. #11
    Senior Member
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    Quote Originally Posted by Longfemur View Post
    It's strictly a matter of personal preference. If you are comfort oriented, wider is better, and if you are performance oriented, narrower is better. Somewhere in between is where you want to be. But if you want my opinion, there's no advantage whatsoever in going wider than what you need for your weight.
    one advantage to wider...you won't need to air up as often. I ride 2 bikes (depending on mood). One (the OCR3) has 26.5s and I have to air it up after 2 or three days. The 32 front and 35 rear on my 520 will go a week without needing air.

  12. #12
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    Wider is better in the dirt.

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