Coaster brake on front wheel ??? (Now with pics)

[John in CR]

Has anyone seen or used a coaster brake on a front drive recumbent? I'm finally getting around to building my own version of my favorite low racer, Bob Horn's Flowroller


Of course my adaption will be electric with my high efficiency series/parallel switching hubbie, and well over 2kwh will fit inside the frame. Since I'm shooting for max aero on this build, and I like clean handlebars anyway, I'm considering going with a coaster brake hub on the chain driven front. I'll have regen along with a big drum brake on the hubbie, so the front brake won't be heavily used, and I think I can overcome any torque steer from the force on the pedals with correction at the handlebars.

FWIW, I may have it rolling tomorrow and will share pics. It's not as basic as Bob's design, but I think it may be a bit better, though that may just be proud papa prejudice.

 

[AussieJester]

Can't say i have read about/seen in my travels...should be a super efficient
bike, best of luck with the fab John.

KiM

 

[jonescg]

I've always been skeptical of front wheel drives

 

[LI-ghtcycle]

I've always been skeptical of front wheel drives

ROFLOL!!!

Now that is COLD!! :lol: :lol:

 

[LI-ghtcycle]

Has anyone seen or used a coaster brake on a front drive recumbent? I'm finally getting around to building my own version of my favorite low racer, Bob Horn's Flowroller


Of course my adaption will be electric with my high efficiency series/parallel switching hubbie, and well over 2kwh will fit inside the frame. Since I'm shooting for max aero on this build, and I like clean handlebars anyway, I'm considering going with a coaster brake hub on the chain driven front. I'll have regen along with a big drum brake on the hubbie, so the front brake won't be heavily used, and I think I can overcome any torque steer from the force on the pedals with correction at the handlebars.

FWIW, I may have it rolling tomorrow and will share pics. It's not as basic as Bob's design, but I think it may be a bit better, though that may just be proud papa prejudice.

Glad to see you are coming to the "dork" side!

I know, I know, some of you are still convinced that recumbents = beanie hats with propellers and pocket protectors, but all I can say is you get the thumbs up and "Nice Bike!" from most anyone you meet including the ladys, so I'm happy to leave those avoiding recumbents in blissful ignorance while I get a steady 25 Wh/Mi. or less no matter how hard I push my motor. :wink:

 

[amberwolf]

Has anyone seen or used a coaster brake on a front drive recumbent?

I haven't myself, though it's part of what I considered using (within the 3-speed IGHs) on the front wheels of ARTOO, which would've had front-wheel motor drive via chain, but I never got far enough in design to build anything and test it.

I did a quick google, and found this:
http://www.recumbents.com/wisil/misc/eliasohn/bill_irvine.htm
which although they're trikes apparnetly have some very similar front-ends to teh bike you're picturing above. Never seen them around, or heard of him, though he's apparently a Phoenix resident. :?

The "python" bike discussed here:
http://www.recumbents.com/forums/topic.asp?TOPIC_ID=4226
with videos linked in first post uses a coaster brake on the front, AFAICT.

If I understand correctly, this trike
http://www.pedersenbicycles.com/vacuum.htm
had versions that used coaster front brakes.

 

[John in CR]

I guess I'll just give it a try. I have a laced up coaster hub already, so that's the easiest route to having front brakes for the initial test rides. Otherwise I need to fab a disc brake mount. I hate to get too much more into until I know the ride won't be too quirky. I'm just happy that by eyeballing it with no jig I ended up with a true frame, and more importantly I nailed the trail at my 3" target. With such a slack head tube angle, I felt it necessary to make my 2 front support struts adjustable, which should give me an adjustable trail of +/- a few cm. Those go on this morning, so I'll know how well that worked out. I might even get to ride this afternoon, which isn't bad, since I picked up the steel last week. 8)

John

 

[John in CR]

Glad to see you are coming to the "dork" side!

I know, I know, some of you are still convinced that recumbents = beanie hats with propellers and pocket protectors, but all I can say is you get the thumbs up and "Nice Bike!" from most anyone you meet including the ladys, so I'm happy to leave those avoiding recumbents in blissful ignorance while I get a steady 25 Wh/Mi. or less no matter how hard I push my motor. :wink:

I didn't realize it was the dork side. If that's the case I'll have to get the big grinder out and chop it into little pieces. If I tried to go full faring, then it would probably get dorky, but I may be able to get away with a front fairing that actually makes it look cool.

John

 

[john7700]

Glad to see you are coming to the "bearded, pot bellied" side!

 

[Pure]

I seriously would not put any kind of coaster brake on the front of any bike that might break 10MPH. Think about how they work, and ask yourself if locking up a front wheel at any speed is good idea. I do see that this is just to see if you like the riding position of the bike, before you put more work into it. But still, I would change the braking as soon as you know if your design is suited to your liking.

 

[John in CR]

I seriously would not put any kind of coaster brake on the front of any bike that might break 10MPH. Think about how they work, and ask yourself if locking up a front wheel at any speed is good idea. I do see that this is just to see if you like the riding position of the bike, before you put more work into it. But still, I would change the braking as soon as you know if your design is suited to your liking.

How do they work? Isn't it just a drum type brake inside the hub. The only time mine locked up as a kid was when I intentionally tried to do so.

On a side note @$#^ )_#! |}+_ &^%$ (*&) $#%^ &*^% !!! Old rusty bottom bracket cups SUCK! I just spent the entire morning getting one off, and finally had to resort to cutting off the face and making and inside cut with the dremel.

On to assembly.

 

[Pure]

I'm pretty sure that's about right. From what I remember (it's been years) it didn't take much reverse pressure from the pedals to lock it up. Yeah you can vary how hard you push, but at faster speeds, you hit a bump and jab your pedal in revers. You're not going to have a good day.

Like I said, for what you are doing it should be ok. I just personally would not want that brake on my front tire, so would change it as soon as I figured out if I had the frame to my liking.

BTW, I do really like the model you are going off of, and can't wait to see what you've done.

 

[John in CR]

It got a bit late for decent pics, but here are a couple of teasers. We'll have to see how it rides. I think I'll have to go to a really recumbent position, because it ending up higher than I was thinking due to not considering how forward the seat needs to be to reach the cranks. Worse case this can easily become a no pedal chopper. Better pics to come.

 

[MadRhino]

That is a very slack steer angle, you're entering the chopper club John.

 

[999zip999]

Non peddling just some pegs. With a front hinge on the seat and springs onthe rear. Some gussets on the front end after you get the ride ability down. Where are going to put the batteries.

 

[John in CR]

That is a very slack steer angle, you're entering the chopper club John.

That's the only way to make the BB in front work, though now I understand why Bob Horn connected the steering tube further up the seat tube on his. Handling is definitely out the window leaving this just a highway cruiser for mostly straight lines, but that was the intent and no suspension makes it a necessity. My biggest concern now is how it handles side gusts of wind...well that and making the 90° out of my street, since the comfortable turning radius may be huge.

John

 

[John in CR]

....Where are going to put the batteries.

Between the 4 long pieces of angle iron of course (the yellow area in the pic at the bottom). There's enough width, length and height for 2 packs of A123 M1's side by side that are each 7p high and 23s long with plenty of room to spare for 20s15ah of Lipo packs and a big brick controller. That's 3.5kwh of pack inside the main frame with plenty of room to hang a big pack under the frame, and behind the seat that will taper to form a proper tailbox once it proves road worthy.

The motor is the 93% peak efficiency hubmotor I've been testing, which has a switch for parallel windings for normal speed cruising with a Kv of about 17, and then switching it to the series connection gives it mountain goat climbing ability. With a non-aero upright it was pushing me 45mph with a saggy 20s pack of well worn Konions, and then pulled me right up a 25% grade.

As long as I can make it comfortable to ride without getting blown off the road, this baby should be able to post some nice no pedaling ES distance numbers for you guys to chase. We might even try to give the 24hr electric scooter distance record of 706 miles a shot, as well as slowing it down for single charge distance shot. I think we can beat the best a Tesla has done at 347 miles, though the world record of 1014 miles is out of reach.

John

 

[LI-ghtcycle]

Nice Work John!

Very interesting design, looks like it should be comfy!

 

[John in CR]

Nice Work John!

Very interesting design, looks like it should be comfy!

Thanks. I had to go a bit wide, 15cm to fit the batts I want, so the seat will need to be fairly high for comfort. I'll be sure to take some good pics when I break it down for painting, since there's some cool stuff that's not really visible. There's conical bearings forming the headset, and I used threaded rod at the top end of the front support struts that enables me to tune the rigidity of the front end and makes the trail adjustable so I can run different size tires and still tune in the steering, assuming I can live with the wacky way the steering works.

If I can't live with it, I'm sure I'll be able to easily sell it, because the locals go crazy over the chopper look.

John

 

[Pure]

That is pretty sweet man. What are your thoughts about a fairing on the front of it?

 

[Harold in CR]

That CroMo tube ??

 

[John in CR]

That is pretty sweet man. What are your thoughts about a fairing on the front of it?

I'll try something eventually, but first I want to get consumption numbers and add the mandatory stuff first like an aero trunk/tailbox and remeasure consumption with each aero improvement. With the 3 long tubes in front I have to think a front faring will help a lot, especially if I can get legs, feet, and cranks behind it.

 

[John in CR]

That CroMo tube ??

Angle iron frame + cheap mild steel tubing + a chromo threaded steerer that I hacked off a road fork + ??? for the BB and chainstays. That may be Chromo since it came from an odd looking Cannondale frame.

I haven't found Chromo in CR yet, and may order a bunch if I can find a bulk price, but it's really unnecessary. Saving a few pounds won't make any measurable difference on a bike to carry well over 100lbs of batteries. 4130 doesn't seem to come in angle anyway, and the space savings of angle over tubing and easy welding are big pluses on my builds. I'd only need chromo if I was building frames for sale internationally due to people's general misconception that weight makes a difference on an ebike.

If welding 4140 wasn't technically challenging and required heat treatment, I'd get it by the sheet and have it bent into angle for lightweight builds. While tubing is structurally stronger than angle, once the angle has enclosed sides it becomes the better choice.

To me ebikes made just of tubing is a design error because it wastes so much space, which is a huge premium on an ebike until the volumeric energy density increases significantly.

John

 

[John in CR]

First go round fitting didn't work out, so I have to make another day of adjustments. I have a feeling that the bike will end up too chopperish and not enough low racerish, but worst case it's been a good learning experience, and I have some interesting solutions to share along with pitfalls to warn against.

 

[maydaverave]

Your gear ratio determines alot about how well a coaster brake hub works. The more leverage you have the greater control but the farther you have to move the pedals. With a 45 chain ring a 20 tooth cog gives you the best control. I have the opposite, a front hub with rear coaster. With a 16 tooth cog i can pedal assist but braking is crap either nothing or locked up. 18 is a good balance but if your only using it for braking 20t is best. any more teeth and I think you would have to turn the pedals to much.