so, I've been coming up with bad ideas again.... And trying to figure out what it would take....
I have an old soap box derby car that was deemed "TOO OLD" to officially race anymore several years back. And I think the Tucson SBD is currently dead anyway (the hill got "populated" with businesses), that's incredibly sad...
I also have a Briggs 5 horse motor, sadly missing a clutch....
I've been hypothesizing about mounting the Briggs on the car, and using the gear set (setup backwards) and chains from a old mountain bike.... (IE variable transmission) so I can drive the thing around at normal speeds, maybe even burn rubber, then when opening it up, have some gears so I'm not limited to 25 mph.
It would need to have the "drive axle" be an idler shaft that would then be attached to the wheels by another pair of chains and appropriate gears, as the wheels are mounted on solid shafts, with bearings in the wheels. I probably also want to get the old school steel wheels instead of the fancy new fiberglass disks. Probably a little less likely to explode. And I could weld the sprockets to them, instead of drilling/fracturing the fiberglass.
I sat down with my buddy, who is an AERONAUTICAL engineer, so again, a bit out of his typical field, and he thinks it to be possible, but not specific enough results to say what gears I would want, etc...
I've been daydreaming of Bonneville for a decade and a half.... It would be a kick to have a mini-landspeed racer...
I figure, a 5hp motor, on say, 400 pound (probably less) loaded car, relatively aerodynamic, ought to be able to turn 100 mph, considering a 2800 RPM wheel speed (12 inch diameter wheels), and a 3600 rpm WOT on the Briggs.
and probably want some of those fancy bicycle disk brakes on the front...
In stock form, depending on the hill, the SBD can push 50+ with gravity alone...
I would probably never actually hit a buck, but it would be cool if I could....
Briggs powered Soap Box Derby Car
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blackagatha
- Posts: 2582
- Joined: March 10, 2007, 12:49 am
- Location: Arizona
Briggs powered Soap Box Derby Car
'63 with 390 & lots of juice. But never enough. Always want more.
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Brian Taylor
- Posts: 1469
- Joined: August 18, 2009, 3:52 pm
- Location: Dallas , Texas
- Contact:
If you want to "play" at a small Briggs powered vehicle I would suggest a better starting point than a SBD racer. Think more along the lines of a King midget.
Here is a link there is a bunch of Crosely stuff first the King midget is at the back
http://oldcarandtruckpictures.com/Crosley/
Here is a link there is a bunch of Crosely stuff first the King midget is at the back
http://oldcarandtruckpictures.com/Crosley/
As my dad used to say, somewhere there was a horse that died a painful death from terminal constipation due to missing a key part of its anatomy.
I'm a mechanical engineer who just happens to be into mountain biking, so maybe I can help. 
Do you have any photos of the car? I'd like to see what the wheels and hubs look like. Also, a sketch of how you see it going together would be helpful. I'm picturing an idler shaft passing through the rear of the car, with a total of three chains. Two on each rear hub, and one to connect the idler to the driveshaft of the engine. Is that right?
Here are some things I think you'd need:
- Chain tensioning device
- Chain guards
- Adaptors to mount disc brakes calipers to the car, and the discs to the hub shells
- Cable routing for the brakes and an actuator pedal
- Throttle mount
- A means to mount the idler
- A derailleur mount (if you intend to use the bike's gear-changing mechanism)
- An adaptor to mount the bicycle sprocket to the driveshaft of the engine, and one to mount a sprocket to the idler
The mechanism for changing gears will be critical and could be problematic. All your sprockets will need to be aligned and true, or else you're going to have issues. I foresee problems with chain skipping. It's hard enough to change gears on a bicycle under load when it's human-powered, let alone when subjected to 5 hp. You'd probably need to throttle down to change gears.
I think I'd run it as a single-speed and use the throttle to control your speed. Set it up so that you can swap out sprockets easily. That way you can tune your acceleration and top speed to suit your needs. Gear it low for zipping around town, then gear it higher for top-speed runs.
Something you could do is have some wheels laced to rear hubs with a freewheel. That way you could throttle down and coast in "neutral" down hills. Also, if you got disc-specific ones you could easily mount your brakes, since they have the mounting points integrated into the hub shell.
Do you have any photos of the car? I'd like to see what the wheels and hubs look like. Also, a sketch of how you see it going together would be helpful. I'm picturing an idler shaft passing through the rear of the car, with a total of three chains. Two on each rear hub, and one to connect the idler to the driveshaft of the engine. Is that right?
Here are some things I think you'd need:
- Chain tensioning device
- Chain guards
- Adaptors to mount disc brakes calipers to the car, and the discs to the hub shells
- Cable routing for the brakes and an actuator pedal
- Throttle mount
- A means to mount the idler
- A derailleur mount (if you intend to use the bike's gear-changing mechanism)
- An adaptor to mount the bicycle sprocket to the driveshaft of the engine, and one to mount a sprocket to the idler
The mechanism for changing gears will be critical and could be problematic. All your sprockets will need to be aligned and true, or else you're going to have issues. I foresee problems with chain skipping. It's hard enough to change gears on a bicycle under load when it's human-powered, let alone when subjected to 5 hp. You'd probably need to throttle down to change gears.
I think I'd run it as a single-speed and use the throttle to control your speed. Set it up so that you can swap out sprockets easily. That way you can tune your acceleration and top speed to suit your needs. Gear it low for zipping around town, then gear it higher for top-speed runs.
Something you could do is have some wheels laced to rear hubs with a freewheel. That way you could throttle down and coast in "neutral" down hills. Also, if you got disc-specific ones you could easily mount your brakes, since they have the mounting points integrated into the hub shell.
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DV65CustomCab
- Posts: 1497
- Joined: July 18, 2006, 4:23 pm
- Location: Elizabethtown, PA
A few years ago I came across a site about a bunch of guys who built miniature replica antique car 'racers' out of Harbor Freight wheels and parts with plywood bodies. They actually had an impromptu racing series somewhere in California. I tried finding it again via Google but whatever tags I used didn't work. You may want to poke around for it. They were pretty much the same concept as what you were talking about. They did caution that building a gas powered vehicle out of wood was probably not the safest idea.
Stop The Longbed Hate! 
'65 F100 Custom Cab bought 2002/Sold 2014
Now: '93 F150 Lightning
'65 F100 Custom Cab bought 2002/Sold 2014
Now: '93 F150 Lightning
5 hp can make you go way fast if done right....
these Jr dragsters have a '' 5 hp briggs block ''
http://www.youtube.com/watch?v=WWW3kiTG ... re=related
these Jr dragsters have a '' 5 hp briggs block ''
http://www.youtube.com/watch?v=WWW3kiTG ... re=related
.
.
.
[b]'' I think what scares me the most about you guys is that I understand you '' ..... KID
'' lookin good, a little paint adds at least 100hp!'' ....... COOTER
'' well an old guy can dream cant he? ''............ICEMAN
''I would donate organs before selling my slick''........ HOOFBEAT RACER
.
.
[b]'' I think what scares me the most about you guys is that I understand you '' ..... KID
'' lookin good, a little paint adds at least 100hp!'' ....... COOTER
'' well an old guy can dream cant he? ''............ICEMAN
''I would donate organs before selling my slick''........ HOOFBEAT RACER
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Uncle Skip
- Posts: 4695
- Joined: July 15, 2006, 8:30 pm
- Location: Pearland, Texas
Aggie.
A true story.
Once upon a time (1962) in a state far, far away, (south Georgia to be exact) a friend and I built a really neat go cart with the motor from his dad's roto-tillers and an old plywood derby car. A big honking Kohler 10 horse power horizontal shaft unit and rope steering. That couldn't have been a good idea even back then.
Mr. Pope was an electrical contractor (more on that at a later time) and also owned an outboard motor and boat dealership on the Kinchafoonee Creek in Albany, Georgia.
Had a long parking lot that ended in the boat ramp down to the water with a pretty steep ramp.
Anyway, we got the cart put together and flipped a coin to see who would give it the initial test run. I didn't know it at the time, but God loves me; Danny won the toss.
He went down the parking lot to the street and then made a U-all turn and headed full speed back toward the ramp.
Unfortunately, at the last minute, he realized we had forgotten all about brakes. That little drop down gizmo with some tire tread did NOT cut it. As a result, "we" promptly launched the cart, Danny, and his father's roto-tiller motor about 50 yards out tp the middle of the creek, never to be seen again. Except Danny.
It was such a beautiful thing to see, the great sweeping arc as the cart literally flew thru the air off the boat ramp and landed nose first in the water.
I still can picture it in my mind.
[Did I mention he had bloody knees when he got back to the boat ramp?]
After this little incident, which seemed to be a recurring theme in the coming years, Mr. Pope developed a nervous tic in his left eye that stayed with him until he died, every time he saw me and Danny together.
He used to say, "you boys aren't building anything are you?"
Is there a lesson or message in this little story? How do sea turtles know to swim the oceans and then go back to the same beach they were born on?
Nobody knows......
But remind me to tell you all about the skunk trap, the ski kite, trout-lining on the river with whiskey, or the Bowie knife deer hunt stories some time.
All true. A man couldn't make this stuff up.
Maybe at Slick Stock.
ROTFLMAO
U@ss
A true story.
Once upon a time (1962) in a state far, far away, (south Georgia to be exact) a friend and I built a really neat go cart with the motor from his dad's roto-tillers and an old plywood derby car. A big honking Kohler 10 horse power horizontal shaft unit and rope steering. That couldn't have been a good idea even back then.
Mr. Pope was an electrical contractor (more on that at a later time) and also owned an outboard motor and boat dealership on the Kinchafoonee Creek in Albany, Georgia.
Had a long parking lot that ended in the boat ramp down to the water with a pretty steep ramp.
Anyway, we got the cart put together and flipped a coin to see who would give it the initial test run. I didn't know it at the time, but God loves me; Danny won the toss.
He went down the parking lot to the street and then made a U-all turn and headed full speed back toward the ramp.
Unfortunately, at the last minute, he realized we had forgotten all about brakes. That little drop down gizmo with some tire tread did NOT cut it. As a result, "we" promptly launched the cart, Danny, and his father's roto-tiller motor about 50 yards out tp the middle of the creek, never to be seen again. Except Danny.
It was such a beautiful thing to see, the great sweeping arc as the cart literally flew thru the air off the boat ramp and landed nose first in the water.
I still can picture it in my mind.
[Did I mention he had bloody knees when he got back to the boat ramp?]
After this little incident, which seemed to be a recurring theme in the coming years, Mr. Pope developed a nervous tic in his left eye that stayed with him until he died, every time he saw me and Danny together.
He used to say, "you boys aren't building anything are you?"
Is there a lesson or message in this little story? How do sea turtles know to swim the oceans and then go back to the same beach they were born on?
Nobody knows......
But remind me to tell you all about the skunk trap, the ski kite, trout-lining on the river with whiskey, or the Bowie knife deer hunt stories some time.
All true. A man couldn't make this stuff up.
Maybe at Slick Stock.
ROTFLMAO
U@ss
I'm not arguing with you. I'm just explaining why I'm right.
Pardon me. Does your deaug bite?
Pardon me. Does your deaug bite?
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blackagatha
- Posts: 2582
- Joined: March 10, 2007, 12:49 am
- Location: Arizona
holy rats skip! that story is epic....
Big M, that's about exactly what I got in mind, 3 chains, 2 on the wheels, with about a 2:1 reduction involved.
Drive axle mounted with unknown type of bearings at this point with rear sprocket set and derailer from bike.
Gokart clutch on briggs, looks about same size as smallest gear on bike sprocket. NOT SURE, but the gokart sprocket LOOKS like it is same as bike chain.
Soapbox car currently equipped with Fiberglass wheels, with 1/2 inch wide "tires" that only prodrude about 1/8 inch past the rim. Wont cut it.... They'll explode, and cant attach gears/brakes.
I'll go get a pic of the car....
I think I'll need to cut off and extend the tail section though....
Big M, that's about exactly what I got in mind, 3 chains, 2 on the wheels, with about a 2:1 reduction involved.
Drive axle mounted with unknown type of bearings at this point with rear sprocket set and derailer from bike.
Gokart clutch on briggs, looks about same size as smallest gear on bike sprocket. NOT SURE, but the gokart sprocket LOOKS like it is same as bike chain.
Soapbox car currently equipped with Fiberglass wheels, with 1/2 inch wide "tires" that only prodrude about 1/8 inch past the rim. Wont cut it.... They'll explode, and cant attach gears/brakes.
I'll go get a pic of the car....
I think I'll need to cut off and extend the tail section though....
'63 with 390 & lots of juice. But never enough. Always want more.
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blackagatha
- Posts: 2582
- Joined: March 10, 2007, 12:49 am
- Location: Arizona
sorry for the crappy pics, it's up in the rafters in the garage right now...
Biggest problem with the whole idea is that the tail wedges off real quick right behind your head. It would have to be cut off and extended, not sure where to cut, etc to make it work out and not look like schizzt.
I think some heavy guage angle iron welded up in a little framework would work well to extend, and make a removable section cover out of sheet steel...
oh ya and a crappy paint sketch
'63 with 390 & lots of juice. But never enough. Always want more.
Cool car!
You may want to confirm that the go-kart sprocket and the bike sprocket are the same width. A bike with 8 or 9 cogs on the rear will require a narrower chain than one with 6 or 7 cogs.
I would suggest finding some hubs that work before doing any modifications to the body of the car. What's the diameter on those axles/spindles, and how are they attached to the car? Are they just bonded to the fibreglass shell?
If disc brakes can't be mounted at the wheels, how about a single disc brake on the idler shaft?
The structural integrity of the shell itself could be a concern too. What does it have for framework, if anything? Perhaps you could build a chassis to support the engine and drivetrain and just slip the body over top?
You may want to confirm that the go-kart sprocket and the bike sprocket are the same width. A bike with 8 or 9 cogs on the rear will require a narrower chain than one with 6 or 7 cogs.
I would suggest finding some hubs that work before doing any modifications to the body of the car. What's the diameter on those axles/spindles, and how are they attached to the car? Are they just bonded to the fibreglass shell?
If disc brakes can't be mounted at the wheels, how about a single disc brake on the idler shaft?
The structural integrity of the shell itself could be a concern too. What does it have for framework, if anything? Perhaps you could build a chassis to support the engine and drivetrain and just slip the body over top?
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Uncle Skip
- Posts: 4695
- Joined: July 15, 2006, 8:30 pm
- Location: Pearland, Texas
One other thing I forgot, its been 46 years, was that the car had a eerie shimmy in the steering right before it launched into the creek.
As I recall, Danny looked like Cale Yarborough at a dirt track sawing the wheel back and forth.
I had no idea about caster back in 1963.
But we do now so you might want to be advised...........
U@ss
As I recall, Danny looked like Cale Yarborough at a dirt track sawing the wheel back and forth.
I had no idea about caster back in 1963.
But we do now so you might want to be advised...........
U@ss
I'm not arguing with you. I'm just explaining why I'm right.
Pardon me. Does your deaug bite?
Pardon me. Does your deaug bite?
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Roger Carter
- Posts: 730
- Joined: July 5, 2008, 7:11 pm
- Location: Corbett, Oregon
In the same time as Skip's story ('62-'63) I had a teacher (Mr. Charles J. Boer) that wanted to impress our class with the value of "word pictures". Those were words, phrases or short stories that evoked a vivid mental image of what was being described.
Skip, without a doubt, you would have set the top mark for the grading curve in that class.
Roger Carter
Skip, without a doubt, you would have set the top mark for the grading curve in that class.
Roger Carter
Truly a great tale Skip, and absolutely hilarious.
BA, I don't think I would convert the car so much as use it's body shell over a decent frame. I'm with you brother on the Bonneville racer - if you are even half/assed serious look up the SCTA rules - they are posted online. I swear that they have a class for about everything but a weedeater. If it passes tech they'll let you run it. I don't know about the chain drive, maybe look at a belt drive like on a Harley? Since the trannys on them are separate and belt driven also they may be your ticket.
Disc brakes from an ATV?
Sounds like a fun project if you take some time to engineer it properly.
BTW, I would up grade the rope steering, LOL.
BA, I don't think I would convert the car so much as use it's body shell over a decent frame. I'm with you brother on the Bonneville racer - if you are even half/assed serious look up the SCTA rules - they are posted online. I swear that they have a class for about everything but a weedeater. If it passes tech they'll let you run it. I don't know about the chain drive, maybe look at a belt drive like on a Harley? Since the trannys on them are separate and belt driven also they may be your ticket.
Disc brakes from an ATV?
Sounds like a fun project if you take some time to engineer it properly.
BTW, I would up grade the rope steering, LOL.
1964 F 100 - I am going to do "something" with it.......
viewtopic.php?f=32&t=15942
1987 Mustang LX Convertible, 2.3 Auto - cruiser.
1994 F 150 XLT 2WD
~ Yes - I adopted another cat..............
Cam L Milan,
You'll be missed my friend.
viewtopic.php?f=32&t=15942
1987 Mustang LX Convertible, 2.3 Auto - cruiser.
1994 F 150 XLT 2WD
~ Yes - I adopted another cat..............
Cam L Milan,
You'll be missed my friend.
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Uncle Skip
- Posts: 4695
- Joined: July 15, 2006, 8:30 pm
- Location: Pearland, Texas
I actually think you're serious, so FYI:
Gates makes a product called Poly-Chain, which is a cogged v-belt. Harley Davidson uses them on their bikes and they're almost indestructable.
I'm like Greg and the rest.
I'd build a special chassis and put the body on that. Maybe a narrowed old go kart frame?
Maybe we will institute a new SCTA salt flats class.
LOL
U@ss
Gates makes a product called Poly-Chain, which is a cogged v-belt. Harley Davidson uses them on their bikes and they're almost indestructable.
I'm like Greg and the rest.
I'd build a special chassis and put the body on that. Maybe a narrowed old go kart frame?
Maybe we will institute a new SCTA salt flats class.
LOL
U@ss
I'm not arguing with you. I'm just explaining why I'm right.
Pardon me. Does your deaug bite?
Pardon me. Does your deaug bite?
Agreed on the belt drive possibly being a better alternative.
The charity bike ride I participated in last summer included several steep climbs. They wreaked havoc on the casual riders who relied on granny low to maintain forward motion. They would pedal as hard as they could for as long as they could, then attempt to shift. Those hoping for a nice crisp shift followed by a much-needed increase in mechanical advantage were instead subjected to the grinding, ticking noise that accompanies a chain that refuses to part ways with the big ring. The end result was usually a loss of momentum followed by a dismount, controlled or otherwise.
The moral of the story is that chains under load don't like to shift. My concern is that attempting to use the derailleur as a cheap means of shifting gears will result in chain skipping or shearing of sprocket teeth. Derailleurs can be notoriously finicky, especially the budget models.
To put things in perspective, I believe the maximum output that Lance Armstrong can maintain on a bike is on the order of 1 horsepower. So you'll need to make absolutely sure that the chain is up to the task!
The charity bike ride I participated in last summer included several steep climbs. They wreaked havoc on the casual riders who relied on granny low to maintain forward motion. They would pedal as hard as they could for as long as they could, then attempt to shift. Those hoping for a nice crisp shift followed by a much-needed increase in mechanical advantage were instead subjected to the grinding, ticking noise that accompanies a chain that refuses to part ways with the big ring. The end result was usually a loss of momentum followed by a dismount, controlled or otherwise.
The moral of the story is that chains under load don't like to shift. My concern is that attempting to use the derailleur as a cheap means of shifting gears will result in chain skipping or shearing of sprocket teeth. Derailleurs can be notoriously finicky, especially the budget models.
To put things in perspective, I believe the maximum output that Lance Armstrong can maintain on a bike is on the order of 1 horsepower. So you'll need to make absolutely sure that the chain is up to the task!
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blackagatha
- Posts: 2582
- Joined: March 10, 2007, 12:49 am
- Location: Arizona