Sticking 29 wheel on front of a 26 bike?

ninetubes
ninetubes Posts: 11
edited September 2007 in MTB workshop & tech
With the likes of Trek espousing the advantages of a 29 up front and a 26 on the rear, I was wondering just how much you would mess up your geometry by sticking a 29 on a 29 specific rigid fork on a standard 26 HT frame corrected for a, say, 100mm travel fork? By my reckoning it shouldn't change things too much, or have I missed some obvious principle?

Comments

  • Sir HC
    Sir HC Posts: 20,148
    Its going to be 1.5inches taller. With the front be higher up, it will slacken the head angle off, making the steering slower.
    Intense Socom
    Inbred
  • But won't the axle to crown height of the rigid 29 fork be around the same as for a 4inch travel 26 fork?
  • Splasher
    Splasher Posts: 1,528
    Sir HC wrote:
    Its going to be 1.5inches taller. With the front be higher up, it will slacken the head angle off, making the steering slower.

    Don't necessarily agree with that: It will depend on the length of the rigid fork you put on. Cyclocross forks are short because they are not suspension corrected for example and MTB forks come it all kinds of lengths.

    I think the more pressing question is why? You may be getting sucked into the marketing.
    "Internet Forums - an amazing world where outright falsehoods become cyber-facts with a few witty key taps and a carefully placed emoticon."
  • nicklouse
    nicklouse Posts: 50,675
    well which ridgid fork? and what sus fork? dont forget sus forks are run with sag.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Why? Well, building up a winter hack bike primarily for going fast on fire roads, and fancied trying something different, courtesy the ebay parts bin.
    Marketing folk would probably insist I went singlespeed as well, but.... no.
  • I suppose I'm wondering if there are any weird 29inch wheel dynamics at play, even if the head angle isn't knocked back too much. If it would be an easy swap, why would you go out and buy a dedicated 96er (or 69er or whatever) frame? Apart from the marketing, obviously.
  • nicklouse
    nicklouse Posts: 50,675
    there is also the fork ofset to consider. in fact many 29 wheels could well fit in a suss corrected 26" fork.

    but either way i have a feeling you wil have something that feels like a pig.

    i dont have the figures to work it out though.

    you really want the mid size. 27.5, or what is it 650 B?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Sir HC
    Sir HC Posts: 20,148
    Splasher wrote:
    Sir HC wrote:
    Its going to be 1.5inches taller. With the front be higher up, it will slacken the head angle off, making the steering slower.

    Don't necessarily agree with that: It will depend on the length of the rigid fork you put on. Cyclocross forks are short because they are not suspension corrected for example and MTB forks come it all kinds of lengths.

    I think the more pressing question is why? You may be getting sucked into the marketing.

    Missed the rigid fork part :roll:
    Intense Socom
    Inbred
  • Probably right - t'was just a thought. Now how about that 29 rear/ 24 front combo? Its going to be the next big thing..
  • Don't forget that this hideous big front/small rear idea was touted by Cannondale back in the early nineties and nobody paid much attention then either.

    It looks hideous and doesn't actually make much sense - "faster acceleration on the rear and smoother rolling on the front"??? Aren't the front and rear wheels covering ground at the same speed, hence the acceleration of your bike is affected by both wheels?

    Unless your rig is lengthening/shortening? Or maybe I am missing something.

    It just seems that the bike companies are desperate to find something else to sell to us - they are businesses, so can't just sell us all a perfectly-functional bike and then leave it at that.
  • supersonic
    supersonic Posts: 82,708
    Tim you are sorta right about the acceleration - you still have to acclerate the front wheel and turn it up to speed!