UPDATE: Speed Racer v6.2 - Lower and Faster

[B. Sanders]

After some thought about aerodynamics vs. "streetability", I have modified the Speed Racer quite a
bit. It's still streetable; but it presents far fewer speed compromises, and yet retains steering
stability and minimal turning radius.

Here's a GIF image of the new design:

http://bsanders.net/SpeedRacer6.2.gif

Design highlights for this version:
- No rear suspension = maximum power transfer
- Extra-low seat height (lower than M5, Jester or Baron)
- M5-style fiberglass rigid seat
- Short wheelbase gives tighter turning radius
- Shallow head tube angle and plenty of trail
- Seat angle is steeper than the M5, Jester or Baron
- Non-power side chain routed to avoid leg interference
- Crank height is similar to M5 - lower than Jester, Baron
- Barnett Williams' chainstay design (1.5" pipe, brazed on)
- Avid mechanical disc brakes (V-brakes on test bike)

The steeper seat angle, shallow head angle, increased trail, minimal chain interference, disc brakes
and shorter wheelbase were all on my wish list after owning an M5 Low Racer. The 1.5" tubular steel
chainstays won't be quite as brutally rigid as the M5's massive sculptured steel stays; but should
be plenty efficient. This design (after it is tweaked a bit) could be as fast and stable as any bike
out there: Any speed deficiencies will be in the engine compartment, not from the bike design. I may
spec a monoblade instead of the BMX fork for later builds.

I think this one looks like a winner, and should be fairly easy to build. I'm going to have to
experiment a bit with the chain idlers quite a bit, it would seem; but the rest of it appears fairly
straightforward. Seat mounting should be a piece 'o cake.

Comments welcomed as always.

-Barry

 

[John Foltz]

B. Sanders wrote:
> After some thought about aerodynamics vs. "streetability", I have modified the Speed Racer quite a
> bit. It's still streetable; but it presents far fewer speed compromises, and yet retains steering
> stability and minimal turning radius.
>
> Here's a GIF image of the new design:
>
> http://bsanders.net/SpeedRacer6.2.gif
>

Hmm... sure looks like a Baron/Jester derivative to me... Not that that's bad...

--

John Foltz --- O _ Baron --- _O _ V-Rex 24/63 --- _\\/\-%)
_________(_)`=()___________________(_)= (_)_____

 

[Bentbiker]

reminded me a lot of a Zephyr, which seems like a very reasonable priced lowracer, that I rarely
seem mentioned here.

John Foltz wrote:
> B. Sanders wrote:
>
>> After some thought about aerodynamics vs. "streetability", I have modified the Speed Racer quite
>> a bit. It's still streetable; but it presents far fewer speed compromises, and yet retains
>> steering stability and minimal turning radius.
>>
>> Here's a GIF image of the new design:
>>
>> http://bsanders.net/SpeedRacer6.2.gif
>>
>
> Hmm... sure looks like a Baron/Jester derivative to me... Not that that's bad...

 

[B. Sanders]

"bentbiker" <[email protected]> wrote in message news:[email protected]...
> reminded me a lot of a Zephyr, which seems like a very reasonable priced lowracer, that I rarely
> seem mentioned here.
>
> John Foltz wrote:
> > B. Sanders wrote:
> >
> >> After some thought about aerodynamics vs. "streetability", I have modified the Speed Racer
> >> quite a bit. It's still streetable; but it presents
far
> >> fewer speed compromises, and yet retains steering stability and minimal turning radius.
> >>
> >> Here's a GIF image of the new design:
> >>
> >> http://bsanders.net/SpeedRacer6.2.gif
> >>
> >
> > Hmm... sure looks like a Baron/Jester derivative to me... Not that that's bad...

Yes, it does doesn't it? This one is quite a bit lower, however. I've since raised the seat a bit on
v6.3, making it even more like an Optima Baron; but with a slightly lower seat height and slightly
steeper seat angle. This change should make it even more "streetable" than a Baron, but much faster
than a SpeedMachine, Taifun, Stinger, Shockproof, etc. That is my design goal. I want stable
handling at all speeds, but excellent aerodynamics, too. Why compromise if you don't have to?

I'm thinking of going ahead with either 2 1/4" stainless steel or possibly 3" 6061-T6 tubing (again,
similar to the Baron and Jester). It will depend upon who ends up doing the bending and the welding.
I'll definitely want mandrel-bent tubes with the 3" aluminum tubing.

-Barry

 

[B. Sanders]

"bentbiker" <[email protected]> wrote in message news:[email protected]...
> reminded me a lot of a Zephyr, which seems like a very reasonable priced lowracer, that I rarely
> seem mentioned here.

It's not a bad price at all, and the plans (blueprints) for it are posted for free on the Zephyr
website. I did take notes from the Zephyr design; but decided that the Baron, Jester and M5 are my
design ideals (with some tweaks for better low-speed handling).

-Barry

 

[Jeff Wills]

"B. Sanders" <[email protected]> wrote in message news:<Xu6Y9.15055$_s4.13852@rwcrnsc54>...
> > > Hmm... sure looks like a Baron/Jester derivative to me... Not that that's bad...
>
> Yes, it does doesn't it? This one is quite a bit lower, however. I've since raised the seat a
> bit on v6.3, making it even more like an Optima Baron; but with a slightly lower seat height and
> slightly steeper seat angle. This change should make it even more "streetable" than a Baron, but
> much faster than a SpeedMachine, Taifun, Stinger, Shockproof, etc. That is my design goal. I
> want stable handling at all speeds, but excellent aerodynamics, too. Why compromise if you don't
> have to?
>

B-

How many rideable prototypes have you built so far?

Jeff

 

[B. Sanders]

"Jeff Wills" <[email protected]> wrote in message
news:[email protected]...
> "B. Sanders" <[email protected]> wrote in message
news:<Xu6Y9.15055$_s4.13852@rwcrnsc54>...
> > > > Hmm... sure looks like a Baron/Jester derivative to me... Not that that's bad...
> >
> > Yes, it does doesn't it? This one is quite a bit lower, however. I've since raised the seat a
> > bit on v6.3, making it even more like an Optima Baron; but with a slightly lower seat height and
> > slightly steeper seat angle. This change should make it even more "streetable" than a Baron,
but
> > much faster than a SpeedMachine, Taifun, Stinger, Shockproof, etc. That
is
> > my design goal. I want stable handling at all speeds, but excellent aerodynamics, too. Why
> > compromise if you don't have to?
>
> B-
>
> How many rideable prototypes have you built so far?

Zero. I'm using the known ride qualities and aerodynamic characteristics of existing designs to
minimize the number of prototypes. The first one will be as close to perfect as possible, based upon
as much data as I can gather. It will be a prototype, by its nature, and I intend to tweak the
design and build a follow-on design.

Why do you ask? Do you think I should go into production with this design? The thought has
definitely crossed my mind. Aside from George Reynolds' bikes, no other lowracers are being produced
on this side of the pond that I know of. I'm pretty sure that this frameset could be produced at a
very competitive price, probably in line with the Zephyr. The business model for lowracers isn't
that great, however. It's a business for people who aren't out to make money - just to have fun. (I
need an income.)

Cheers,

Barry Sanders From the Frosty Midwest USA

 

[Jeff Wills]

"B. Sanders" <[email protected]> wrote in message news:<VsgY9.20121$_s4.14962@rwcrnsc54>... <snip>
> Why do you ask? Do you think I should go into production with this design? The thought has
> definitely crossed my mind. Aside from George Reynolds' bikes, no other lowracers are being
> produced on this side of the pond that I know of. I'm pretty sure that this frameset could be
> produced at a very competitive price, probably in line with the Zephyr. The business model for
> lowracers isn't that great, however. It's a business for people who aren't out to make money -
> just to have fun. (I need an income.)
>

I think you're on the right track with building a prototype, but...

Don't think about mandrel-bent tubes. Don't think about aluminum. Close the carbon-fiber catalogs
and tape them shut.

Build a frame out of mild steel, something like 1.5" to 2" square,
1/16" wall. This should cost something like $20 in materials. *Make sure* everything works the way
*you* like. If something's messed up, you can chop it up or build a second prototype for the same
minimal cost. Building real ridable bikes will teach you 100 times as much as making drawings.

We of the OHPV (Oregon Human Powered Vehicles) are building chassis to go into full fairings. The
frames are 1.5" square steel. We're going through this process with the aim of having several
streamliners ready for our races in May.

Jeff

 

[Tom Sherman]

Jeff Wills wrote:
>
> I think you're on the right track with building a prototype, but...
>
> Don't think about mandrel-bent tubes. Don't think about aluminum. Close the carbon-fiber catalogs
> and tape them shut.
>
> Build a frame out of mild steel, something like 1.5" to 2" square,
> 1/16" wall. This should cost something like $20 in materials. *Make sure* everything works the way
> *you* like. If something's messed up, you can chop it up or build a second prototype for the
> same minimal cost. Building real ridable bikes will teach you 100 times as much as making
> drawings....

Jeff,

What about using some large diameter exhaust tubing ('muffler moly") bent (pun intended) at a local
muffler shop? This should be inexpensive, and the weight will not be a concern on a prototype.

I have thought about having a frame custom built from large diameter titanium alloy tubing. Getting
it right would be easy, since the frame geometry would be an exact copy of the Earth Cycles Sunset
Lowracer [TM].

Tom Sherman - Quad Cities USA (Illinois side) RANS "Wavewind" and Rocket, Earth Cycles Sunset and
Dragonflyer

 

[B. Sanders]

"Jeff Wills" <[email protected]> wrote in message
news:[email protected]...
> "B. Sanders" <[email protected]> wrote in message
news:<VsgY9.20121$_s4.14962@rwcrnsc54>...
> <snip>
> > Why do you ask?
>
> I think you're on the right track with building a prototype, but...
>
> Don't think about mandrel-bent tubes. Don't think about aluminum. Close the carbon-fiber catalogs
> and tape them shut.

> Build a frame out of mild steel, something like 1.5" to 2" square,
> 1/16" wall. This should cost something like $20 in materials. *Make sure* everything works the way
> *you* like. If something's messed up, you can chop it up or build a second prototype for the
> same minimal cost. Building real ridable bikes will teach you 100 times as much as making
> drawings.

Hmm. I appreciate what you're suggesting; but I question it. For one thing, I don't see how you can
expect to build a bike that handles well without examining other bikes that handle well, and
designing carefully. That's what I'm doing. Also: Speed isn't my only goal. I want my bike to look
great, too.

Believe me, I'm not eager to spend money. I'm not dreaming of carbon fiber just yet - though my
neighbor across the alley built carbon fiber wheelchairs that took gold medals at the Olympics. He
knows a thing or two about fabricating with carbon fiber, so carbon is probably in my future. It's
not terribly expensive, compared to the price of a new Optima Baron! (that's how I look at it)

> We of the OHPV (Oregon Human Powered Vehicles) are building chassis to go into full fairings. The
> frames are 1.5" square steel. We're going through this process with the aim of having several
> streamliners ready for our races in May.

Are you running a 1.5" square unsupported frame tube from end to end of the entire bike, without
reinforcement? Doesn't your bike exhibit some flexiness? That's what I was concerned about with
thin-walled 2" steel tubing.

-Barry

 

[Jon Meinecke]

On Sat, 25 Jan 2003 06:19:28 GMT, "B. Sanders" <[email protected]> wrote:

Barry,

I like the drawings you've posted and incorporating ideas from other bikes seems quite reasonable. I
look forward to hearing about how the project works out, particularly the fabrication details. More
power to you!

>"Jeff Wills" <[email protected]> wrote in message
>>
>> Don't think about mandrel-bent tubes. Don't think about aluminum. Close the carbon-fiber catalogs
>> and tape them shut. [...] Building real ridable bikes will teach you 100 times as much as making
>> drawings.

In the software development industry there's a truism that "running code trumps an unimplemented,
superior design".

I think Jeff's point was about not worrying too much about the finer details on the first prototype,
but rather get something you can ride and tweak then make another, better design, incorporating what
you've learned in an iterative fashion. In a sense, starting from an existing design inherits many
iterations, but there's still probably much to learn for oneself. That's probably part of the fun!

In terms of a 'business' plan, if you come up with a design that works well and can be made by
hobbyists, you might consider selling plans. (Consult a lawyer about liability...)

Jon Meinecke

 

[Jeff Wills]

Tom Sherman <[email protected]> wrote in message news:<[email protected]>...
> Jeff,
>
> What about using some large diameter exhaust tubing ('muffler moly") bent (pun intended) at a
> local muffler shop? This should be inexpensive, and the weight will not be a concern on a
> prototype.
>

I did this on a lowracer in, umm... 1991. 2" diameter muffler pipe, bent and then welded to a rear
triangle from an upright. 17" front wheel, Lightning seat. The only reinforcement to the bent tube
was under the seat, where a plate gusset spanned the bend.

Despite having the front and rear wheels in different dimensions, much less the same plane, the bike
was quite rideable. Too bad I never pursued the design further- it looked a lot like Ed Gin's
20/700C Festina.

Jeff

 

[Jeff Wills]

"B. Sanders" <[email protected]> wrote in message news:<Q%pY9.23992$4y2.1713@sccrnsc04>...
> > We of the OHPV (Oregon Human Powered Vehicles) are building chassis to go into full fairings.
> > The frames are 1.5" square steel. We're going through this process with the aim of having
> > several streamliners ready for our races in May.
>
> Are you running a 1.5" square unsupported frame tube from end to end of the entire bike, without
> reinforcement? Doesn't your bike exhibit some flexiness? That's what I was concerned about with
> thin-walled 2" steel tubing.
>

Take a look at the ZOX FWD bikes: http://www.zoxbikes.com/index_e.html
. Their frames are 1.5" square mild steel. If it's good enough for Sergio, it's good enough for us.

Our frames are reinforced with small gussets at the (cut and welded) bends. However, I can't tell
you how they ride... the frames are still being fabricated. If things go bad, I'll report it here.

Jeff

 

[Jeff Wills]

Jon Meinecke <[email protected]> wrote in message
news:<[email protected]>...
>
> In the software development industry there's a truism that "running code trumps an unimplemented,
> superior design".
>
> I think Jeff's point was about not worrying too much about the finer details on the first
> prototype, but rather get something you can ride and tweak then make another, better design,
> incorporating what you've learned in an iterative fashion. In a sense, starting from an existing
> design inherits many iterations, but there's still probably much to learn for oneself. That's
> probably part of the fun!
>

Exactly, Jon. Like I said, you'll learn far more by *building* and *riding* than you will by
contemplating drawings. Even building copies of an existing design will teach you far more about it
than just taking measurements.

FWIW: my "real life" is software testing/QA . You'd be amazed at the number of bugs that get found
*after* the "final code" gets delivered.

Jeff

 

[Mikael Seierup]

"Jeff Wills" skrev...
> Take a look at the ZOX FWD bikes: http://www.zoxbikes.com/index_e.html
> . Their frames are 1.5" square mild steel. If it's good enough for Sergio, it's good enough
> for us.

I actually had a chance to look at some brand new Zox-20 clones last weekend. Pretty cool bikes and
looked fairly easy to make. If we get a local building group started here that might be fun to try.
Unfortunately I didn't bring my digicam.

There were also some nifty CNC-drilled (?) chainrings. Up to 72 teeth and you can even get your name
on them. Cheap too at ~50-60 usd. They hadn't yet tested how well the rings held up, but I just need
one for the annual 200 m sprint anyway. Addys here if anyone wants to know more.
http://hpvklub.dk/kontakt.htm

Mikael

 

[Jon Meinecke]

On 27 Jan 2003 16:09:23 -0800, [email protected] (Jeff Wills) wrote:

> contemplating drawings.

This can be fun, too, though. People approach creative tasks in many ways...

>FWIW: my "real life" is software testing/QA . You'd be amazed at the number of bugs that get found
>*after* the "final code" gets delivered.

No, I wouldn't be surprised.

We put those behaviors into the code so that 'you guys' will have something to do. %^P

S/W development is iterative, too. It all about tolerances.

Jon Meinecke

 

[Jeff Wills]

Jon Meinecke <[email protected]> wrote in message
news:<[email protected]>...
> On 27 Jan 2003 16:09:23 -0800, [email protected] (Jeff Wills) wrote:
>
> > contemplating drawings.
>
> This can be fun, too, though. People approach creative tasks in many ways...
>
> >FWIW: my "real life" is software testing/QA . You'd be amazed at the number of bugs that get
> >found *after* the "final code" gets delivered.
>
> No, I wouldn't be surprised.
>
> We put those behaviors into the code so that 'you guys' will have something to do. %^P
>
> S/W development is iterative, too. It all about tolerances.
>
> Jon Meinecke

Yup- which developers you can *tolerate*, and which aren't worth the space they occupy.

(FWIW: not only am I a QA guy, I'm *married* to a software engineer. She wrestles with firmware
code... Yikes! She's also prettier than me. )

Jeff

 

[Tom Sherman]

Jeff Wills wrote:
> ... Despite having the front and rear wheels in different dimensions, much less the same plane,
> the bike was quite rideable. Too bad I never pursued the design further- it looked a lot like Ed
> Gin's 20/700C Festina.

Jeff,

As far as I know, Ed has only had stock framed Ross Festinas (Festine?). You may be thinking of
Warren Beauchamp's Barracuda, which was basically a Festina clone with some significant
modifications:

Indirect steering Monoblade [2] instead of the Festina's fork with a bend in the right blade Step-up
jackshaft [2]

[1] < http://www.wisil.recumbents.com/wisil/barracuda/barracudaframe.htm
>
[2] These in turn were apparently copied by Earth Cycles for the Sunset Lowracer - the monoblades
appear practically identical.

Tom Sherman - Quad Cities USA (Illinois side) RANS "Wavewind" and Rocket, Earth Cycles Sunset and
Dragonflyer

 

[Dave Larrington]

Ed *has* recently had a rear triangle transplant on his Festina.

Dave Larrington - http://legslarry.crosswinds.net/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Tom Sherman]

Dave Larrington wrote:
>
> Ed *has* recently had a rear triangle transplant on his Festina.

Ed *has not* recently updated his Festina page, however.

< http://home.earthlink.net/~gkpsol/festina.html >

Tom Sherman - Quad Cities USA (Illinois side) RANS "Wavewind" and Rocket, Earth Cycles Sunset and
Dragonflyer