I got into and accident on my bike yesterday and got pretty banged up. Im just thankful that im relatively okay, accept for some road rash and a sprained ankle. I was only going about 30-35. It was my second run down my road. It happened just after i put my head down a little bit. Any reason why this would happen or what i could do about it. Maybe a steering damper? I wasnt going super fast? i put up a pic of my bike any input is greatly appreciated. :thumbsup:
Isn't that the bike you built from scratch?? I hope you didn't mess it up too much? Maybe you need higher handlebars? You know that bike is pretty tall! Maybe the rake on the neck needs to be stretched out a few more degrees? you know? maybe the front wheel is a little too close to the frame and needs to be out farther. sorta like a chopper, but not that far out?
Bearings woirn out in the front will do it pretty easily... Just the tread pattern of the tire will do it at some speed no matter what ya do.. I'd say the build of the bike looks good.. Taller handle bars would probably give ya more control over the rig, but if the tire doesn't like anything over 33 mph or something, thats just it's limit.. What kind of rubber is it? Is it some of those Chinese Horrible Freight wheels and tire setups?? If so those things are dangerous.. :hammer:
I'd shorten the fork legs till the bike is level and make the bars wider and taller. The build itself was great to watch and you did a good job but some fine tuning is always needed on a scratch build. Sometimes the trial and error part hurts though. Glad you're not hurt bad, now it's time to sort it out and keep on going!:thumbsup:
OK..try this little experiment, squat down in front of the bike (if it doesn't hurt too much!) and pinch the front tire and rim front to back between your knees, now reach up and grab your bars and try to steer the front end, how far will the bars turn side to side with the wheel in one position? I don't know how thick the tubing is that you used to build your forks with, but it may not be strong enough to have that long of a fork design. When you leaned down like you said, you changed the weighting on the front tire and caused a little wobble, (which is semi normal with these small wheels) and the long forks allowed it to compound into a tank slapper, and away you went! More rake (least desirable) shorter forks (kind of hard to do at this point) or a stronger front end (more desirable) may be what you need. Try the experiment first.
wow thanks for the help guys :thumbsup: im going to try to answer everything in one post lol this may be long. Now the wheel that i used on this bike of from northern tool. they have cheap bearings but they are make to go up to 25mph. They neck i used is off a bike it has bearing and bearing cups. The tubing i used for the bike is 1/8in dom tubing, this is what i used for the front forks. My spacers for my front wheel is tight but there is a little play in the bearings, im talking like 1/16 or 1/32 of an inch. When i put the wheel between my knees there is almost no play. I could try to tighten up the bolt near my triple trees though. Ive already stiffened the trees up so there is no play. Now the top tree bolts through the handlebars. The rear suspension is independent and probably could use a little work. It is the bike i made from scratch and all the damage is that the foot peg is scratched up and so are the handle bars. ill have some pictures later, but all my welds held :thumbsup: thanks for anymore input
my buddys little indian had some. couldnt figure out why untill we yanked the rear off. blew the bearing. prob his fat ass......
and dont feel bad i got in some mud on a hill side and dumped mine bad. bruises and cuts all over my left leg.....
that was before my carb got royally f'd. not from the wreck though
and dont feel bad i got in some mud on a hill side and dumped mine bad. bruises and cuts all over my left leg.....
that was before my carb got royally f'd. not from the wreck though
Alexp, Whether you realize it or not you just hit on the cause of your problem. Soon as I looked at your pic I said to myself "his rake and trail are not with safe limits". Go to the top of this page and do a search for rake and trail. There are four pages of posts for that subject and I remember some of them have some pretty good graphics illustrating proper rake and trail. It's almost impossible to just explain it in words; so take some and learn it. And besides, if you're going to be a builder it's absolutely essential to understand it. If you choose to ignore this aspect of bike building you "WILL" (not might) end up in a hospital. Good luck. Ogy
Lots of good advice here as far as I'm concerned. Another thing that I believe we should keep in mind when we are mounting tires on our minibike rims is to remember that NO two wheeler in the whole universe was produced with flat section tires. As others have said; there are a lot of reasons why a particular bike under some circumstance decides to go into a spate of undampened oscillation. Flat bottomed tires are never helpful and in conjunction with other faults are always unhelpful.
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Your death wobble can more then likely be solved with math and a welder.
Try this formula...
RB Racing Professional Rake and Trail Calculator
Try this formula...
RB Racing Professional Rake and Trail Calculator