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  • Another Canyon sizing question (grand Canyon 29er)
  • sidetracked
    Free Member

    Are modern bikes shorter than old bikes? My old bike is a 1997 Roberts dogsbolx with 120mm stem and layback post. Its about 50mm longer from bar to post than the Grand Canyon 29er I’ve just bought (plus layback). I like the Canyon but I’m struggling to know if its the right size.

    The online sizing system said medium and the UK rep said that I should stick to that, he felt happier with me buying the medium and adding a an extra 10mm or so to the stem length than going up a size. It took another 3cm on my inseam for the online system to recommend a large, so I felt the rep was probably right. I’m 5′ 11″ with an 85cm inseam.

    But riding it, I keep pushing my bum to the back of the seat and generally feel more upright, and this is after sliding it back a cm. I know the old bike was all wrong by modern standards so I don’t know if its a useful frame of reference. Should I persevere and adapt to this shorter, modern bike or does it sound like I need to go up a size? I’m not sure what I should be looking for here.

    Incidentally, both bikes are the same length in theory. The Roberts has a 550mm top tube and a 120mm stem, the Canyon has 590mm and 80mm. But the roberts is slacker and has more post showing, hence the difference in length from post to bar. Here’s a pic:

    Does anyone in Brighton have a size large I could swing a leg over for comparison?

    Cheers
    //A

    ukcanyon
    Free Member

    Hi there sidetracked,

    It’s an interesting comparison with your Roberts. It isn’t me who you spoke with at Canyon, but as a fresh pair of eyes on it and I still agree with the medium size. I am also 5’11” and waiting for my Canyon 29er in Medium to arrive.

    Yes, obviously the bars are closer to the saddle on your new Canyon. However, the Roberts has a significantly slacker Seat Tube angle so if you look at the distance from the centre of the BB to the bars, I think it would actually be quite similar. I feel you’re right about thinking about a shift in geometry styles over time. Seat tube angles in XC bikes, particularly racey ones, are definitely steeper than they used to be, even from just a few years ago. On my current Grand Canyon CF I used to run a 20mm lay back post but have swapped it out for a 0mm offset post to get further over the pedals. I ride much further back on the road bike.

    Also consider that on the Large frame the Head Tube is 15mm longer so you bars will be higher, which they already are from the Roberts. Looking at the picture you could try swapping the stem to angle the other way. Obviously this won’t make it longer but will get the bars closer to the height you are used to form your Roberts.

    As I said, I think that the Medium is the right size, but if you are still struggling with the size please give me a ring at the Canyon UK office on 0208 5496001.

    WIth kind regards,

    Trevor @ Canyon UK

    monkeyboyjc
    Full Member

    Ive also 5’11” and also ride a medium grand canyon. I wouldnt like to compare it to any of my bikes from the 90’s as geometry has certainly move on a fair bit. Also the change from 26 to 29 comes into effect….. I must admit that I do ride with the saddle all the way back and the stem flipped to drop the bars slightly. As ukcanyon says yhe headtube is 15mm longer on the large and would personaly put me off.

    Had mine just over a year and its been a great bike btw.

    sidetracked
    Free Member

    Just realised I never responded to anyone on this – thanks for the replies I received.

    At the time I was staying on the tarmac whilst trying to decide if it was right for me and even today it feels too short and upright for that style of riding. However, from the first time I took the bike off road it felt right, really right. It climbs and descends incredibly well. I now have no doubt whatsoever that its the right size for me. The large would have been too high at the front for sure.

    Cheers

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