dirt jump geometry ?

**racerjosh** · 05-05-2008, 04:14 AM

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 ..

**Frankenschwinn** · 05-05-2008, 06:05 AM

Originally Posted by racerjosh

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 ..

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.

**Cru Jones** · 05-05-2008, 06:29 AM

Originally Posted by Frankenschwinn

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.

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.

**kidwoo** · 05-05-2008, 08:16 AM

Seatpost: 27.2
Seatclamp: 31.8mm
Front mech: 31.9mm

So dialed for dirtjumping.

**racerjosh** · 05-05-2008, 11:20 AM

ah right .. well heres a picture of it anyway .. http://i212.photobucket.com/albums/c...josh/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?

**WestCoastHucker** · 05-05-2008, 11:45 AM

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

we still need geo numbers...

**1453** · 05-05-2008, 12:02 PM

Originally Posted by racerjosh

http://i212.photobucket.com/albums/c...josh/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

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

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.

**racerjosh** · 05-05-2008, 12:51 PM

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/M...?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 ?

**ebrider510** · 05-05-2008, 01:35 PM

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.

**racerjosh** · 05-05-2008, 02:09 PM

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

**DirtBag** · 05-06-2008, 05:02 AM

You have it nailed down to the 2 bikes - but have no idea on the geometries of either?

**racerjosh** · 05-06-2008, 09:21 AM

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

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

**sittingduck** · 05-06-2008, 09:59 AM

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.

**racerjosh** · 05-06-2008, 10:00 AM

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

**racerjosh** · 05-14-2008, 08:27 AM

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