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dirt jump geometry ?

Discussion in 'BMX & Dirt Jumping' started by racerjosh, May 5, 2008.

  1. racerjosh New Member

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    right then, without telling you what the frame is yet, would these geometry specs be good for dirt jumping?

    13" or 15"
    7000 series aluminium
    Bottom bracket: 68mm
    Seatpost: 27.2
    Seatclamp: 31.8mm
    Front mech: 31.9mm
    Headtube length: 120mm
    8mm dropouts
    Disc/ V-brake compatible
    Box section seat / chainstays

    ^^^ there the specs given so i dont know anything else about it like the top tube length etc ..
    #1
  2. Frankenschwinn New Member

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    None of what you mention here really matters. Its all about tt and cs length and ht and st angle as well as bb height.
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  3. Cru Jones Active Member

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    Yep. And if they just give you the specs like that and don't state the TT length, chain stay length, bb height, etc, then I would say no, it is not a good dirt jumping frame.
    #3
  4. kidwoo Celebrating No-Pants Day

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    So dialed for dirtjumping. ;)
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  5. racerjosh New Member

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    ah right .. well heres a picture of it anyway .. http://i212.photobucket.com/albums/cc313/blatajosh/12528.jpg .. its no particular brand (named brand-x) but its had very good reviews. the reason i was going to choose it was because of the good reviews and because i can buy decent parts (brakes, cranksets, headsets, forks etc) with the extra money

    or.. i was thinking of a 14" Da Bomb XLR-8R frame (or maybe 14" sputnik / depending on which is better for dirt jumping) .. buying this frame would probably mean that i would have to use some of the old crappy parts that are currently on my instinct frame

    i probably already no the answer to this question but is the Da bomb frame better for jumping (maybe lighter ?) than the instinct frame?
    #5
  6. WestCoastHucker Active Member

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    a picture really isn't worth a thousand words...

    we still need geo numbers...
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  7. 1453 New Member

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    if it has no brand name how does it get reviews? :think:

    I mean, personally, as long as it comes in rootbeer it would be pimp for DJ. Screw the CS length, HA, TT length, and all those superficial "numbers". No joke.:cheers:
    #7
  8. racerjosh New Member

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    nooo the name is 'Brand-X' the actualy name of the frame is Brand-X Dirt Jump Frame MK III from http://www.chainreactioncycles.com/Models.aspx?ModelID=12528

    finding it hard to find many geo specs for the da bomb .. not even any on their website

    the main problem is most of the frames ive seen on here ive never even heard of.. and ebay'ing them in the UK comes up with 0 results..

    the main frames ive heard of is Yeti, Kona, Cove, Norco, Club Roost, DA Bomb, DMR, On One, Identiti, Specialized, Orange, Giant and Saracen - there all off the top of my head and i may be able to think of some more if i really had a good think about it

    above, is a list of the frames im most likely to be able to get from ebay with relative ease, so they are the main frames im focusing on. im looking to spend a max of £150 (about $300) on a frame (2nd hand, or new if it comes under that price tag) for that i basically want a lightweight and strong true dirt jump geo frame :)

    any suggestions ?
    #8
  9. ebrider510 New Member

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    the bits of Geo information left out are the really key points for a jump frame. if the company doesn't give you access to the geo it probably isn't worth buying even though it does appear to be intended for jumping. try emailing chainreaction and see if they will give you the numbers.
    #9
  10. racerjosh New Member

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    to be honest .. i have realised that i have to spend a little extra for that somehting special

    now i have norrwed it down to 2 frames.

    1) DMR Trailstar
    2) Kona Scab

    now .. these are both 2 well known manufacturers for their products and i know that they both do dirt jump/ trail bikes. although i cant find any geo specs for them .. i will email them both to get the info :)
    #10
  11. DirtBag New Member

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    You have it nailed down to the 2 bikes - but have no idea on the geometries of either?
    #11
  12. racerjosh New Member

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    yeh i nailed it down to 2. i havent done that by geo since i dont no whats good and whats bad for a DJ'er i just ride the dam thing :greedy: but i kinda want to get the geo right for my next bike.
    ive mainly narrowed it down by price and by who the manufacturer is (so it will actually be a half decent peice of kit, wether its truely for DJ or not)

    havent got a reply from Kona yet but i got a reply from DMR
    DMR trailstar geo: (all measurments are in MM, apart from angles which are in degrees and weight which is in KG)

    Top tube: 544 (21.4 inches)
    head tube angle: 71
    seat tube angle: 72.5
    Seat tube CT: 402 (15.8 inches)
    wheelbase: 1033 (40.6 inches)
    BB height: 226
    chain stay length: 419
    head tube length: 110
    front mech: 28.6
    frame weight: 2.62KG
    #12
  13. sittingduck Active Member

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    16.5(419mm) chainstay is a bit long if you plan to do much street/park riding. Try to stay under 16" if you can. The rest looks ok.
    #13
  14. racerjosh New Member

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    yeh i was looking at the chain stay length as it does look quite long from pictures as well .. im just awaiting Kona's reply for their bike
    #14
  15. racerjosh New Member

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    right then after some serious searching i have found one of two bikes i am going to buy :) one of them might be a felt jump shot weighing in at 14kg
    http://www.feltracing.com/06/06_shot/jump_shot/geo.html

    the other might be a Norco One25

    the geo on the felt looks good apart from the chain stay length at the top end of 16"

    i havent seen the norco one125 geo yet but i have been told that it is a very nimble bike

    the norco is kind of my first choice, although its a 24" that im looking at and i dont really like 24" :huh: it finish's its auction in 4days so i have until that time to decide....

    anyone had experience with the Norco One25 or the Felt Jump Shot ?

    Any good ?

    regards
    josh
    #15
  16. sperkins New Member

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    i would look at the bike in person before you buy it...
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  17. Durt New Member

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    I own a '05 Felt Straight Shot. Same frame, pretty much. I love the bike. My only complaint is the long chain stays. It is very hard to manual but I do just fine on the street and the parks. I bought it as a complete bike, marketed as a Freeride Hardtail. Had a big 'ol 130mm fork, gears, the whole bit. I've replaced the fork, the front rim, the cranks, the pedals, the chain, removed the front brake and went SS. A little heavy with the burly rims but they are strong and take a lot of abuse. Knowing what I now know, would I buy it again? Ehhh probably not because my preferred style of riding has shifted to primarily DJ's. I'd go with a DJ specific steel frame.

    #17
  18. snaky69 New Member

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    Norcos ride very well, although they tend to be on the heavy side of things.
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  19. racerjosh New Member

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    decided not to go for the norco as its a 24" rim (dont like 24")
    so im going to get the felt jump shot for £200 (around $400 ?)

    setup of it is pretty good, Halo combat rims, dirtjam forks (changing to dirt jumper 1's), hydrolic brakes etc etc so i think its at a good price

    not too botherd about manuals, just about jumping :) and with the bike weighing at around 14KG .. i reckon its light enough :)
    #19