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  1. #1
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    28c tires on Giant OCR2?

    Hey all, I'm doing a tour on my Giant OCR2 this summer. Yes, I realize it's a road bike and not ideal for touring, but I did an 850 mile trip on it last summer, fully loaded, and had no problems.

    My question is, do you think I would be able to fit 28c tires on it? I have 25's right now, and the only thing I'm worried about is the amount of clearance in the chainstay. I can't get to a bike shop for a little while, so any information would help. Thanks!

  2. #2
    Senior Member teacherbill's Avatar
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    Have a set of 28s on my OCR2 and I do not know how many miles they have on them. When you get ready to put them on the bike you need to not have them inflated. Install the wheels first then pump them up to your psi. I ride with airless tires from out in Denver, so when I installed them it was a tad more difficult. I had to release the brakes then reconnect them. I lost 3 to 5 miles per hour, but made up for it because a lack of worrying about flatting while on the road far, far from home. When the tires were constructed I had them set-up for a simulated 110 psi rating. A little harsh, but, I like a hard ride. The next set will be constructed to a 120 psi rating. Have a good time on your tour.
    Bill from Sebastian

    Mongoose Cruzbike Conversion
    Giant OCR2
    "Pain is only temporary. Quitting is forever." Lance Armstrong

  3. #3
    Senior Member fast_track's Avatar
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    I have a 2006 Giant OCR 3 and have Michelin Top Contact 28's on the bike. These tires have a wanna be cyclocross tread pattern and run a bit wider that slicks. I have no issues. The closest contact point is with the tire and the underside of the rear caliper brake. If I am not mistaken, in 2006 all the OCR series had long reach caliper brakes. My sister has a woman's OCR2 from 2008 and it has the long calipers too. If I were a betting man, I would say that you would probably be fine with 28's.

  4. #4
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    Awesome, thanks for the info guys. Do you really think I would lose 3-5 mph going from a 25 to a 28?

  5. #5
    Mechanic/Tourist
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    Quote Originally Posted by stephenboyd View Post
    Awesome, thanks for the info guys. Do you really think I would lose 3-5 mph going from a 25 to a 28?
    I see no reason that such a small change would result in that type of loss. It's easy to blame slower speed on one factor, but many things can slow down a rider. No matter what type of tire you have, the amount of tread contacting the road is EXACTLY the same given the same tire pressure and weight of bike/rider. The only factors that are different are weight (a tiny effect in this case), rolling resistance (somewhat of an effect but not that great unless comparing a tire with smooth tread to one with knobbies) and tire flex (again at higher tire pressure not that bid a factor).

  6. #6
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    That's what I thought. Thanks for the response, I'll probably upgrade before I leave.

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