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Road 28mm Tires on a Giant Defy

Discussion in 'Cycling Department Forum' started by Bram, Aug 30, 2016.

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  1. Bram

    Bram Senior Member

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    Ordered a set of Continental Grand Prix 4000s ii 28mm. Let's see if they actually fit in my frame :)

    To be continued
     
  2. arthur666

    arthur666 Senior Member

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    I hope they fit. That's a good size for general road riding.

    I ran 28's on an old racing bike I was using as a commuter. It was an eye opener to feel the difference a slightly fatter tire makes. I ended up taking that bike on all my road rides while my other road bike with 23mm tires collected dust.

    When I was racing, most people ran 23mm, some even ran narrower ( 700x18! ) Now I shun anything narrow. All of my bikes now have wider than normal tires, except for my classic racing bike, which mostly just sits around looking pretty anyway.
     
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  3. Bram

    Bram Senior Member

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    My future bike needs to have space for 32mm or more for sure as I don't want to be sticking to perfect tarmac all the time. I have seen too many cool dirt roads the last month that I really would have checked out with bigger tires.
     
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  4. Bram

    Bram Senior Member

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    Did you really feel a difference @arthur666 ?
     
  5. arthur666

    arthur666 Senior Member

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    Yeah, you can run lower pressure and pavement feels smoother. Probably slows you down a tiny bit (just guessing, didn't log my rides or use a bike computer), but worth the trade for my purposes. I was on Specialized Turbo Armadillo 700x28 . Also, it *might* be all you need to tame the dirt roads you want to ride. I took this thing on plenty of dirt roads.
    DSC02888.jpg
    I loved this bike, but I eventually cleaned it up and got it to a good home. :)
     
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  6. Bram

    Bram Senior Member

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    Thanks @arthur666 What I read on the web the wider tires are having less roll resistance so technically they should even speed you up a few bits.

    Oh and that bike is awesome :heart:
     
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  7. arthur666

    arthur666 Senior Member

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    Thanks! Long story to that one... http://www.cycleexif.com/mclean-fonvielle Built in my neck of the woods (so proud, and so saddened by the tragedy)
    Anyway, it was given to me, rusty and in disrepair. I removed rust, touched up paint, rode it for a few years as a fixie. At one point, an addled old hippie walked up to me and the bike, stared, and said something like, "I knew the guy who built that bike[frame]. I think he would've loved the way you're using it."
    Eventually, after it had pulled it's hard duty as a daily commuter, trusty steed for drunken nights rides home from the bars, I gave it a retirement. Had it totally repainted, re-decaled, and I built it up with some scrounged Suntour Superbe Pro. Sold it to an appreciative good friend for what I had in it... Could've made a some money selling to a rich doctor, but that didn't feel right since someone gave it to me because they knew I would put it to good use. Anyway, I digress...

    I think I've heard someone else mention something to the affect of wider tires having less rolling resistance (up to a point). Sounds backwards to me, but I'm no physicist. :)
     
    Last edited: Aug 31, 2016
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  8. Flaviu

    Flaviu Senior Member

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    One thing is sure. Bigger contact surface - more rolling resistance, smaller contact surface - less rolling resistance. In fact, these are two things ;). Also I'm not a physicist but I like a nice "physic":imp::
    [​IMG]
     
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  9. Bram

    Bram Senior Member

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    NOOOOOOOOOOOOOOOO!

    It literally is one micrometer too large to fit and gets in the way with the caliper. Man this sucks as those tires looked absolutely fabulous under my bike.

    Back to 25mm and ill keep this set for my future bike with discbrakes ;)
     
  10. arthur666

    arthur666 Senior Member

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    @Bram : if its close there's still a chance that you could mount larger calipers. For example : http://brandscycle.com/product/shim...ions=1017202&gclid=CPSa4Yfl8M4CFQ6BaQod39MNsQ
    From what I remember, those calipers will let you use bigger tires. Take your bike to a shop and see if you can mount those calipers and pads will still line up. There is a range of up/down adjustment, and it is worth a shot.
    If you haven't taken the tires off yet, give us a pic of how close it is. :)
     
  11. Bram

    Bram Senior Member

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    Naah it's going to be too expensive as I am using Ultegra calipers. Ill just save this set for a future bike and order a set of new 25's.

    I have put the old tires back already so can't show you. But it was so close it was literally just touching the brake and the fork, damnit :)

    I used Continental Grand Prix II tires which are already a bit on the large size I read. Their 28mm set fits 30.1mm which is the issue.
     
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  12. arthur666

    arthur666 Senior Member

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    Oh. Touching the fork means it wouldn't have worked anyway.
     
  13. dazzyb2k3

    dazzyb2k3 Well-Known Member

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    I'm going through the whole 23/25/28 thing too. Up until 4 or 5 years ago i used to run 21's. I've even had 18's but that was downright scary in the corners lol

    Of the three road bikes i use regularly, i have 23's on my best bike, 25's on my 'normal' bike and 28's on my training bike.

    In terms of rolling resistance I can't say i've felt a noticeable difference. If anything my brain always tells me the thinner tyres 'feel' faster. That may or may not be the case but If there is a difference either way, it's marginal and as much about compound as width IMO. Comfort wise I found the 25's to be noticeably better than 23's. The 28's a little better again but for me 25's seems to be the sweetspot. Some of the roads here are in terrible condition so they all get a real hammering throughout the year. Once the 23's on my best bike need replacing i'll definitely switch to 25's.

    That said, I haven't really tested the same bike on different widths of the same make/model so it's not an apples to apples comparison. Also i'm a light rider so i can get away with running low pressures across the board and is probably why I don't feel a huge advantage of 28's over 25's. I also ride exclusively on the road these days. If your riding is a bit more varied then there's probably a stronger argument for 28's or bigger.

    On the whole i'd say the shift towards wider tyres is a positive one. You get noticeably increased comfort with no real downside apart from a few extra grams of rotating weight.
     
    Last edited: Sep 29, 2016
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  14. Bram

    Bram Senior Member

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    The 25mm i am using now measure 27mm so I am getting there :) Would still love to run a lot wider though.
     

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