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Thread: upgrading forks

  1. #1
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    upgrading forks

    I have a 10 year old mountain bike (a Diamond Back axis). I want to put new forks on as currently it has no suspension- i have had different opinions over whether this will be possible. Some say it is no problem, others say it was not designed for suspension and will upset the balance. Can anyone give me advice on this?
    thanks very much

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    Quote Originally Posted by womble365
    I have a 10 year old mountain bike (a Diamond Back axis). I want to put new forks on as currently it has no suspension- i have had different opinions over whether this will be possible. Some say it is no problem, others say it was not designed for suspension and will upset the balance. Can anyone give me advice on this?
    thanks very much
    It is possible to put a suspension fork on a older non-suspenion bike, but the statements made are ture:

    A. It was not designed for suspension - True.
    this does not mean that you can not add a suspension fork, but you have to know that the frame and
    components were not intended to accomodate the flex and movement of a suspension fork. If you keep that in mind in your riding style, you should be ok. I would not reccomend anything beyond
    100m travel,
    80m travel max would probably be best.

    B. It will upset the balance - True
    As the suspension fork will weigh more than the rigid, and it will probably change the rake of the front
    ork and lenghten the wheelbase. These are not all bad, just different.

    some other issues to consider:
    The size of the headtube, older bikes could have a 1inch tube, while the newer bikes have the 1.1/8inch tube. If you have the 1 in tube, it will limit the number, particularly of high end forks that are available.
    Also, you may have a threaded headset, and finding a fork with threads, is near impossible.
    Last edited by btadlock; 03-16-06 at 07:41 AM.
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    It might be worth getting a new bike, because you could be putting a lot of stress on the headtube, and the geometry would be altered greatly. You should go to your LBS and ask them about it.
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    Senior Member Chumley360's Avatar
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    I had thought about doing that to my old Diamondback Topanga so I spent some time reading and asking about swaps, geometry, and all the rest. By the time I was done I had lots of info that only sort of helped and had decided not to do it. I did the math and found that for what I would have paid for the fork and a new headset(mine had busted bearrings) I could get a used older hardtail for about the same price and less E-Bay searching. But that's just me.

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    10 years isn't that old at all. Bike companies were advertising "suspension corrected geometry" as early as 1994, and 1 1/8 headsets were introduced in 1989. It's very likely that your bike is already compensated for a 2.5" travel fork (63mm), and I'd bet money it's got a 1 1/8" head tube.

    Measure the axle to crown race distance on your current fork. If it measures 400mm or longer, the frame was built for front suspension.

  6. #6
    Bike Junkie roccobike's Avatar
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    I went the route you're considering. YES it can be done, but btadlock was right about the issues he raised. Simply put, You will change the geometry of the bike. It will lift front, raising the standover height about 1 inch (maybe a little more) and may affect handling. It will add weight, about 3 to 4 lbs to the front. On the other hand, if you're travelling on technical trails now, it will allow you to be more aggressive when confronting obsticles. I modified a Nishiki chro moly frame and I've not seen any stress problems with the head tube. The comment about 1 inch vs. 1 1/8 inch and threaded vs non-threaded are very important. The comment about a high end fork being difficult to find and very expensive is correct. However if you have a 1 inch, threaded head consider the Suntour SR3000 available from NYCbikes.com. I paid about $36 with shipping for one.
    There is one other important issue that has not been discussed before, cantilever brakes. If you have V brakes, disregard my comments here. If you have cantilever brakes, you have to make your own bracket to attach the brake cable to the fork to enable the brakes to work. Alternately, you can buy an old, high end fork off of ebay or a bike shop that has the brake cable post built on. OR you can convert the front brake to V.
    If you go the Suntour route, be aware, this is a really low end fork. It is a simple spring fork with limited travel and no rebound damping. But ours has withstood several rides on local MTB trails.
    If I had it to do over again, I would still buy the Suntour fork and make the change, but I've decided not to buy a high end fork for this bike. At some point, the comment about buying a newer bike with a frame designed for a fork is correct.
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    Commited Suicide WannaGetGood's Avatar
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    I would say that you could add travel to it. Just not to much.

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    Senior Member joetronic's Avatar
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    I was going to do this to my old DimondBack wildwood. I ended up making it a rigid SS. After doing the research and talking to my LBS it ended up not being worth the upgrade.

    BTW, if you do get a new bike instead, keep the rigid bike. I find after I ride the rigid for a while, I pick my lines better when on the suspension fork bike since on a rigid, you have to avoid more stuff in the trail so your teeth don't rattle out.

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    Quote Originally Posted by MERTON
    it will make the handling REAL screwy.
    Well, that depends. If you're referring to a highly technical trail, yes the change will affect handling, but if you're referring to cross country, I don't agree. In fact, this bike is now my ATF for level, non-technical fast trail riding. The slightly longer wheel base combined with the fork made for one fast bike on fast trails. I prefer it over all three of our late model MTBs.
    Last edited by roccobike; 03-17-06 at 08:56 PM.
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    Quote Originally Posted by WannaGetGood
    I would say that you could add travel to it. Just not to much.
    Good point. The fork I used is a low end fork with only 40mm travel. The more travel, the greater the amount of lift and change to the geometry. At some point, Merton's statement becomes correct, the handling becomes screwy no matter where you ride.
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  11. #11
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    Wasn't the Diamondback Axis a pretty good bike in it's day ? If it's only 10 years old it should be fine with a short travel fork(80mm or less).

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