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  1. #1
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    Suspension forks upgrading for a 92 MTB

    Hello All,

    I am new for mountain biking, but I really enjoy the XC in local park.

    I bought a 92 Diamondback Apex. It is a solid bike. I am thinking of change the fork to the one with suspension. My budget is tight. I plan to bid one on ebay. I wonder if you could give me some idea?

    Thanks,

    Jingye

  2. #2
    Old School Rad mtnbiker66's Avatar
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    Check the headtube size. That bike may have a 1" rather than a 1 1/8"
    Like a circus monkey on a stolen Harley......

  3. #3
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    Quote Originally Posted by mtnbiker66 View Post
    Check the headtube size. That bike may have a 1" rather than a 1 1/8"
    Looks like a 1" threaded fork... I know RST still makes suspension forks in that size, though many these types of forks are common on x-mart bikes, so watch out for the crap on ebay.

    I would actually stick with the solid fork, less things to break.

  4. #4
    Bike Junkie roccobike's Avatar
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    If that's a 1" threaded head, the cost of a new RST would be prohibative based on the value of the bike. I've made that conversion before using a cheaper Suntour fork, a Duo-Track fork and a used Rock Shox Judy. The results are mixed and, unless you're doing the work yourself, it can be costly. As in, you can buy a used hardtail from around 99 or 2000 for the amount of money this can cost.
    Some of the trade-offs include changing the geometry of the bike so that the handling on turns changes for the worse.
    If the brakes are cantilever, you have to come up with a cable stop or the front brakes won't work.
    A low end fork will wear out quickly and become soft, robbing power.
    I'm not saying, don't make the change, but don't have any illusion that this will make an old MTB anything like a current bare-bones entry level bike cause it won't. But it might cost you almost as much if you can't make all the changes yourself.
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  5. #5
    Senior Member sykerocker's Avatar
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    Right off the bat, take off your current fork and do a few measurements. If it's threaded, you're going to want to stick with a threaded fork or you're facing the expense of a new headset along with the fork.

    OK, now you've got to get two critical measurements. First is the diameter of the steerer tube (the part that goes through the frame's head tube). It's either going to be 1" or 1-1/8". Then, measure the length of the steerer tube. You're going to have to find that length or longer, at which point you'd cut it down to match the original.

    Then look at your brakes on the current fork - I'm assuming they're either cantliever or V-brakes. Which they are, and which type your possible replacement fork handles, will have some effect on your brake levers. Here again, you want to be able to stick with your original brakes, and suspension forks are predominantly, if not entirely, V-brake - if you're talking rim brakes, of course.

    I'm kinda looking at the same possibility for my Gary Fisher Gitchie Gummie, and am coming to the conclusion that it's going to be more cost effective to leave the stock fork on it.
    Syke

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    Hi All,

    Thanks for your reply. I took some picture of my bike. It does have cantilever brakes. I also wonder by changing the suspension fork, the frame would tilt up. I probably would just change to a fatter tire. Any suggestion for other upgrade?

    Jingye
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    Bike Junkie roccobike's Avatar
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    Are you sure about that being a 92 model year? I don't think so. The rear U-brake (also called a horseshoe) and the decal "DIAMOND BACK", two words, not one, tells me that's a older bike. (My guess, 87 or 88, I could be wrong).
    Due to the rear brake, you can not upgrade to V-brakes, well you can on the front, but not the rear. You need to share with us how many speeds you have on the rear and if its a freewheel or freehub with a cassette. I briefly owned a Diamondback from around that era. It had one of those rare Shimano 6 speed freehubs with a cassette instead of a freewheel. If you've got a 6 speed, you can upgrade to 7 speed, going to 8 or 9 speed will be more difficult.
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    I have an inexpensive suspension fork if you want to try it. It does have a 1" threaded tube. Also, I can pitch in most if not all brake components to convert it.

  9. #9
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    Quote Originally Posted by roccobike View Post
    Are you sure about that being a 92 model year? I don't think so. The rear U-brake (also called a horseshoe) and the decal "DIAMOND BACK", two words, not one, tells me that's a older bike. (My guess, 87 or 88, I could be wrong).
    Due to the rear brake, you can not upgrade to V-brakes, well you can on the front, but not the rear. You need to share with us how many speeds you have on the rear and if its a freewheel or freehub with a cassette. I briefly owned a Diamondback from around that era. It had one of those rare Shimano 6 speed freehubs with a cassette instead of a freewheel. If you've got a 6 speed, you can upgrade to 7 speed, going to 8 or 9 speed will be more difficult.
    You might be right. There is a lable on the frame shows, 'Warren county expires by 1992'. So, it might be an older model. I paid $50 from craigslist. I took some picture of the back. Maybe you can tell the story of the bike.
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  10. #10
    Banned. mazpr's Avatar
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    Take in consideration the increase height of a new fork, place the front tire in a book, piece of wood to raise it be it 3" (80mm) fork... and test the height and how much clearance it will be. Looking at the seat tube I think you are going to be ok.

    Check if its worth the investment, a brand new Mongoose Teocali Comp is in the 900 or so... brand new, disc brakes, check the ratings, good bike!



    To give you an idea, here is mine...





    Mine is 1"-1/8 Took me about an hour to do everything with a saw, lol!
    Last edited by mazpr; 10-10-08 at 08:05 PM.

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