Suspension , Jumps

S

sigzy

Member

Jul 17, 2002

1

0

• Jul 17, 2002

• #1

I own A 1997 KDX200. I'M STARTING TO JUMP THE BIKE QUITE HIGH (I FLAT LANDED APROX 10METRE HIGH ON SATURDAY AND WAS REBOUNDED INTO THE GROUND) AND WAS WONDERING IF THERE ARE ANY OPTIONS AVAILABLE OR IF ANY FORKS AND TRIPLE CLAMPS OFF OTHER BIKES WOULD FIT, TO SAVE ME HAVING TO BUY ANOTHER BIKE.
I CAN HELP WITH ANY ENGINE PROBLEMS, AND A KEEN FOR A REPLY, THANKS

 

C

clutchcover

~SPONSOR~

Feb 21, 2002

363

0

• Jul 17, 2002

• #2

Thats over 30 feet high. Thats really high for a flat land. You might retrofit some kx forks. Not sure as to the work involved though. Some people on this site have done it. Not sure if any other bikes with better suspension would have the same size forks, but maybe. It all comes down to whether you want to stay with conventional or go to inverted. I hear that marrizochi makes some good forks, not sure though.

 

J

jmutiger

Member

Oct 10, 2001

169

0

• Jul 17, 2002

• #3

I wish I had jumps like that with no gravity around my place.. 10 metres to flat!! Your the undisputed, undefeated king of fish tales around here :)

Up the oil, grab a set of heavier springs, and get a measuring tape :)

Jon!

 

M

mprest4

Member

Nov 14, 2001

90

0

• Jul 17, 2002

• #4

10 meters high!! that's about 2.5 stories high
i remember the last time i put my bike on top of my 2 story house and jumped off to a flat landing. it killed me.

force = mass times acceleration

acceleration due to gravity = 9.9 m/sec

i forgot the formula for velocity

one of you engineers calculate the velocity and force of the impact of a 220lb bike + rider dropping from 10meters

 

T

Tantrum

Member

Dec 4, 2001

197

0

• Jul 17, 2002

• #5

Maybe you should try skydiving. :p

B.

 

K

KTA

Member

Jul 14, 2000

287

0

• Jul 17, 2002

• #6

velocity = distance over time

 

A

andrew

Member

Aug 7, 1999

278

0

• Jul 18, 2002

• #7

OK, so maybe Sigzy's exagerating a little. Its a bit of a past-time down here ! Besides, it may have looked like 10 metres from his vantage point on the pegs & looking down over the bars !

Sigzy, mate, here's atip. Put in a decent set of aftermarket fork springs that'll suit your weight. Do a search on 'fork springs' to find heaps of opinions.
Just as a guide, I'm about 80kg and I've put in a set of eibach springs for an XR400. I'm told that stock Honda springs for the XR 400 or 600 are good too. The rate to get depends on your weight and preference. At 80kg and a preference for stiff springs (good for big jumps) I put in .42's. I don't bottom out (much) at the MX track.
Hope this helps a bit.

Cheers mate,

PS If you really did jump that high, I'd consider getting a KX500 instead ;)

 

Last edited: Jul 18, 2002

M

mprest4

Member

Nov 14, 2001

90

0

• Jul 18, 2002

• #8

ok - i found my old physics book. the speed of the bike falling from a 30 ft drop to a flat landing would be 55mph at impact. the force would be approximatly 4500 kgs . better get some good stiff springs

 

B

BB007

Member

Apr 4, 2002

22

0

• Jul 20, 2002

• #9

10 meters wow, you should take up super cross. And I was always told women couldn't add or measure because they were always told 2" was 6" if you know what we mean. LOL

 

N

Nevada Sixx

Member

Jan 14, 2000

1,033

0

• Jul 21, 2002

• #10

my friend flatlanded from over doing a 80 foot double,, he broke both his arms from the impact, then fell over and landed on them. he had a 99kx125..so maybe nicer forks won't keep the bike up from a jump like that even if you did have better forks.. but if i get my own kdx,, first thing im doing is getting new springs.