Gravity racer - Calling all daredevils!

[Philphine]

hey, you never showed what it looked like.

[breakurnees]

Sorry about that. I meant to do a short ride, assess the effectiveness of my bungee dampeners and than come back and do a second video. I felt confident and went the whole way. The steering was shaky anytime it wasn't pointed straight, and it got away from me on that last curve. While my buddy was shooting the speedometer, I was picking up speed and then wobbling like crazy. I let off the front brake, grabbed the rear and tried to ride it out, but got sideways and then highsided it.

I'll try to shoot a video of the bike in its current state soon.

[fast eddie]

can i make a suggestion about wobbles? usually on g-bikes wobbles are not from speed. if you're going under 40mph then i would definatel suggest that it's not a speed wobble issue. get rid of the bmx fork and install a road fork w/ a negative angle and at least 3 inches of reach. set up your seat (i would highely suggest getting rid of the seat and resting on knee trays) so that none of your body weight is being supported by your arms. a correctly built bike should be able to be ridden w/ no hands, and you should be able to move the bike right/left under you while riding w/out moving your torso,head,shoulders. also, make VERY sure that your rear wheel is mounted straight, and that it is tracking in line w/ the front wheel.
fast eddie

[breakurnees]

Thanks Eddie. I don't have a seat, I have kneelers, but I don't think i could balance without hands. My bike has a raked out springer fork. I was thinking about swapping for a bmx, but I may look for a road fork. The bike caught wobbles anytime the front tire wasn't pointed straight. Since the frame is flipped and stretched, I think a BMX fork would still have some forward rake. Is there something other than the forward curve on a road fork that makes it better?

[fast eddie]

what kind of springer fork? i would definately suggest flipping the frame back to right back up, when ya lip the frame you increase the racke, which is good if your drag racing and only going straight, but terrible in turns as you have found. a rigid bmx fork would be great, some guys say shock forks are better, some say rigid is better, thats up to hte rider i suppose but i would definately suggest a normal fork and righting the frame. forks will usually either have a bend in the tubes or drop outs welded on, either way what they give the fork is caster, like a grocery kart caster wheel, it's steadier when trying to maneuver than if it were straight up and down. do you have a lowrider fork on the bike?

[breakurnees]

It is a straight springer fork, but I flipped the bracket it is on to rake it further. I think just putting a standard fork on will help. Righting the frame would be a pain at this point, and the wheelbase would become a lot shorter. I'll give that fork a ride first, and then try righting it if it is still twitchy.

[fast eddie]

ya got bigger brass than i, ya couldnt pay me enough to ride a flipped frame again, i raced on one in a world cup event and it scared the bageezus outta me! springer forks are taller so they increase rake, a flipped frame increases rake, flipped brackets increase racke, but .. the best set up is to leave the head tube angle where it is. a few inches of wheelbase is not worth the dramatic loss of maneuverability your experiencing with your set up. ride safe brother
fast eddie

[OUTLAW]

hey Eddie, these guys are funny. hope we don't hear about em how they died. wow, flipped bikes, springers, yep, they got bigger brass then me too. I guess if they are going around 30 they can get away with it. but over 60, too scary for me. when I built mine I went 68 on it. no prob. but it was set up right. of course I had good mentors like you and alot of others who new how to build em an ride em. sooo, this ought to be interesting.
take care my friend.


Outlaw

[fast eddie]

good to hear from ya outlaw and thanx for the kind words. i didnt get to do any riding this summer, alot of baby mama drama to deal w/, but im ready for next summer with a new bike and a new streetluge ! trial and error is a good way to learn, hopefully no serious crashes happen, building/rebuilding/tweeking/tryin new setups .... that's all part of the fun! ive ridden some wrecks down the hills thinking i had a brilliant idea, i would trade those lessons for anything. notice i dont post pix of any of those wrecks .. only the good bikes!

fast eddie

[OUTLAW]

yep, your right. but even posting the bad is good to learn from. I went back thru all the builds and there is some good ideas, some work some don't. I was lucky to get it done right the first time. over on gravity bike's there was alot of good builders with lots of good advice. that helps alot when your running down a road over 40 mph. putting on the right gear is a + to keep ya half safe. lucky I had no problems. I don't build em anymore. just no time and I too have to go a distance for the good runs even here in the PNW.lol.I torn the bike down an rebuilt it back to a BMX and gave it to a deserving kid here in my hood. all you daredevils, stay safe. good runnin on the hills, it's a blast.

Outlaw

[cobraontrike]

Has anyone heard of the crested butte chainless race. I have done it the last two years and I've seen gravity bikes compete. The race is so much fun. The only rule is no pedaling. U can have a chain if u have a coaster brake but it has to be tied to the sprocket so u can't pedal. I did it on my trike two years ago and a tall bike this year

[fast eddie]

ive wanted to that race for years, never seems to work out for me, is it a dirt road or paved?

[subadrew]

all paved except for the last 200 yards(ish) which is kinda sketchy =)

[TXBONE]

you have to look up gravity racing tuna canyon california. Its an unbelieveably steep road here in topanga canyon ca. Its called TUNA CANYON ROAD. The road borders topanga canyon and malibu dropping down the hole mountain at an insane grade. People come from all over and i see them all the time as i drive home to TOPANGA.They hold soap box races and gravity bike races illegally here. They turned it into a 1 way road about 5 years ago, which makes it ideaI for gravity racing bikes and crazy skateboarders too. Get going 62 MPH on my downhill bike, kinda lame in the street, but if i had a gravity bike, id bet i could get it going 70 mph plus.

[S.I.N. CYCLES]

breakurnees -
One thing for sure springer fork is probably not well suited for speed. You should really just try swapping the fork to a BMX fork something with a 30mm offset will give you a silly stable ride, like hands behind your back in the straights. Although you will have a bit of wheel "flop" when you steer with the fork to much. I think you will be happy with the results. Flipped frames are all about body language, which scares a lot of folks. You could always move towards a 0 offset fork (flatland bmx fork) for tighter steering. S.I.N Brothers have went through multiple forks from wrecking our consensus is to use the beefiest forks you can get a hold of! I have ridden flipped, not flipped, and of course our hybrids that combine a bit of both. They all just take getting used to, and sometimes run better on different types of roads.

Kneelers are great, but you can not solely depend on them, having sturdy rear pegs is super important. Being able to shift your weight between handlebars, knees, and pegs is absolutely key to getting the most out of any road. We have found seats to be near pointless except for causing serious damage to anything between your legs guy or gal.

Keep riding!