Racer X

[etard]

I love the geometry of the Jr. Brute bike as built by Thud for me, and while we get some things sorted on that drive system, I couldn't just leave Grange Racer in the shed, so I'm building her into what I hope to be a formidable race bike: Racer X

Well, Thud stripped her bare before his Exodus back to Michigan, and left me here to pick up the pieces. LOL The bike is a perfect platform for a monster sprocket setup, but I have everything I need here for a proper Jackshaft drive, which I think will look cooler. So here is Racer X before It was stripped:

The Black One





Here is the mockup of the drivetrain I plan to run:

Ok, so here I have the 7KW Collosus, but I plan on using a 130 KV Turnigy 80-100. Drive system is 15mm GT2 belt drive 20T motor 60T jackshaft. I am using a hollow steel BMX shaft and one of Recumpence freewheel to shaft adapter. I will use screws to attach the 16T Dicta freewheel to the 60T pulley, allowing the motor to freewheel. I need to find a low profile bearing for the pulley, or I might incorporate a one-way bearing here for instant throttle response without the freewheel delay. I also plan on using a much shorter Jackshaft tube, this is just for visual detail. OK, on the other side we have a 14T #219 sprocket which I will probably weld to the shaft, going to this sprocket:

http://www.ebay.com/itm/180744415606?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649#ht_500wt_969

I believe this sprocket is a 46T #219 sprocket, but I'm not sure until I actually get it. There are a few motorcycles using #219H chains for their camshaft gears which I think is the same pitch as #219. It's not a big deal as I can just switch to a bit larger (64T) rear sprocket and bigger drive sprocket if not. What I am trying to do is get "inside" of the brake so that my rear sprocket is smaller than a 8" rotor allowing my to run the two off the disc brake flange, and keeping things relatively narrow. This way the Brake caliper will be above the 219 chain, otherwise, I'll just throw my Magura Hydro rim brakes on the rear. I also plan to make a proper battery box inside the front triangle. Don't get me wrong, these boxes are the best for switching out batteries, charging and don't get in the way. I just want to clean it up a tad.

I have a modded 12 FET Thud helped me build, and I'm gonna try putting sensors in the Turnigy and running at 72 volts. She should be a runner! I hope to get everything together before Jay64 gets back from Hawaii. Then we'll take all the bikes up to Grange and run some laps! Second best thing to actually running in the race.

 

[Byte]

Niceeee! I'm going to follow this build

 

[Jay64]

Nice, love the name too. Dang, between both your bikes, I'm going to have to figure out a better bike setup so that I can run with you when I get back.

Dude, while writing this I just realized that the bike shop in Corona never gave me back my original rim and spokes when they put the hub in the 20" rim.

 

[etard]

Corona? Circle City Cyclery? If so, I was there last Friday getting some custom spokes cut. Jay, when will you be back on the mainland?

I think this build should move fast. Most of the lathe work will be done tomorrow at work, I don't think my lathe has the accuracy for these rpm's and I want a smooth drivetrain.

A few minor changes:

1. Rather than use a 1/2" shaft adapter for the 14t 219 sprocket then welding the whole mess together. I have decided to get a 3/4" shaft and taper the other side down to 1/2" for the freewheel adapter and one way bearing.

2. I'm going to attempt an eccentric jackshaft housing for belt tensioning. Basicly, chucking the housing in my 4 jaw chuck and boring a hole off center. I have many years of practice at this. :lol:

 

[Whiplash]

Awesome! Glad to see you getting moving on a new project here on the forum! I am hoping to have something for maybe the next race or two down the road, I am stuck with work for now for a while!

 

[recumpence]

Hey Etard,

With that much torque, you will probably need to go with 20 or 25mm wide belt. That 15mm wide belt will probably skip. I have found 15mm wide belts tend to skip above 5kw or so (not sure the NM torque, so this is a loose number). Or you could move to a Gates Polychain or Contitech Syncromesh belt in the same 15mm width. They are the same pitch, but much tougher material.

Personally, I would move to a 20mm or 25mm width.

I agree with the comments above. It is good to see a new build from you on the forum!

Matt

 

[Hillhater]

If you are going with a 3/4 shaft, you could avoid some machining & components ..freewheel etc ..and simply fit one of the many go kart clutches that carry changeable 219 sprockets..
It may make it easy on your controller etc as well ?
There is a ton of 3/4" belt drive jackshafts stuff available for go karts.

 

[AussieJester]

With that much torque, you will probably need to go with 20 or 25mm wide belt.

Definitely,..... etard, i used what you have planned on my blue cruiser and it skipped a few teeth
when you gave it a handful...

KiM

 

[etard]

Whip, I'm gunning for you! LOL. Sorry you missed the last race, Grange is a great track and it's actually closer to you than me!

Matt,
That is a good point on the belt slip, I may have to rethink my gearing combinations and just go with the kart sprocket on the disc brake flange and put like a 20 something tooth on the motor. With a large motor pulley, belt slip shouldn't really be an issue, right? It will be easier to mount the standard sprocket than the cam sprocket I suspect.

AJ,
What size motor pulley were you using? I have a 20T here that might give me a little more engagement. If I use the 95T sprocket on the rear, I may need a much larger motor pulley anyway. I am just trying to get this together as cheaply as possible with parts I already have.

Hater,
I love that idea and may have to go in that direction if I decide to mount the monster sprocket up and do a direct drive. Thanks for reminding me, I had forgot about that option. I can't believe nobody has done it yet!

Anybody have thoughts on the One way bearings? I wonder if 2 or 3 of these with only a 3:1 reduction will be enough to go without the freewheel:

http://www.vxb.com/page/bearings/PROD/1-2inch/Kit8651

 

[etard]

Update on some things I did this morning:

I found this go cart rear hub and a tube I had cut for some bearings, so I will prolly go this direction. I'll just use a hole saw to cut out the motor plate that Thud left on the bike ( thanks bud ) and bolt it on. The mount to the left in the pic is a thrift store find I was gonna repurpose using 3/4" needle bearings. That setup would be fairly stout, but I think what I have will do. On the sprocket side I have bored out the key way on the ends so the bearing nuts from the old hub are squeezing the sprocket centered. I'm gonna try Dimpling the shaft and using the set screws to hold it in place. Then I'll drill a hole in the sprocket body , heat it and fill with solder. Crazy enough to work?

Finally getting around to making a sprocket adapter. This piece was a little small, but the biggest I could fit in the lathe. It's thick enough to either cut in half and make 2 or dish the sprocket in toward the wheel more. In order to ensure it is round, I will drill and tap the mounting holes, and then hold the sprocket in the lathe to cut out the center. I'm having fun and feel lucky to have all the tools I need right here. Although a welder would be nice to have, huh Thud? :x :lol:

 

[John in CR]

Why freewheel the motor on a race bike? Personally, I'd shoot for regen braking to reduce some of the load on the mechanical brakes, but even without regen get some extra cooling flow through the motor since a ventilating centrifugal fan on an outrunner looks like a no-brainer that already exists for some types of RC use. PaulD is a lot lighter than many of us and his motor was pretty darn hot at over 200° several minutes after a race, so we should be after all the cooling we can get, which includes while we're off the throttle for curves.

 

[AussieJester]

AJ,
What size motor pulley were you using? I have a 20T here that might give me a little more engagement. If I use the 95T sprocket on the rear, I may need a much larger motor pulley anyway. I am just trying to get this together as cheaply as possible with parts I already have.

Unsure...it was two teeth larger than the pulley that came stock on the recumpence reduction drive, which
IIRC is ~17 tooth Matt? I can't seem to locate the pulley i had on it, i have one here thats a 17tooth hence
i am thinking this might be the stock one...Either way the one i used ripped the teeth off the belt, literally, i had
two belts one with teeth on it one without LoL

KiM

 

[etard]

Why freewheel the motor on a race bike? Personally, I'd shoot for regen braking to reduce some of the load on the mechanical brakes, but even without regen get some extra cooling flow through the motor since a ventilating centrifugal fan on an outrunner looks like a no-brainer that already exists for some types of RC use. PaulD is a lot lighter than many of us and his motor was pretty darn hot at over 200° several minutes after a race, so we should be after all the cooling we can get, which includes while we're off the throttle for curves.

John, I don't believe it's possible to regen brake a non-hub setup let alone go without freewheeling. In my experience the chain will wrap up because of the resistance of the motor. You know I still have that hubmotor on the backburner, which has had some minor progress which I will resume soon.

AJ,
Bad news bro, I will attempt with this setup and may have to order a larger motor sprocket and belt. Thanks for the heads up, by any chance do you know what the reduction pulley tooth count was?

 

[AussieJester]

Why freewheel the motor on a race bike? Personally, I'd shoot for regen braking to reduce some of the load on the mechanical brakes, but even without regen get some extra cooling flow through the motor since a ventilating centrifugal fan on an outrunner looks like a no-brainer that already exists for some types of RC use. PaulD is a lot lighter than many of us and his motor was pretty darn hot at over 200° several minutes after a race, so we should be after all the cooling we can get, which includes while we're off the throttle for curves.

John, I don't believe it's possible to regen brake a non-hub setup let alone go without freewheeling. In my experience the chain will wrap up because of the resistance of the motor. You know I still have that hubmotor on the backburner, which has had some minor progress which I will resume soon.

AJ,
Bad news bro, I will attempt with this setup and may have to order a larger motor sprocket and belt. Thanks for the heads up, by any chance do you know what the reduction pulley tooth count was?

Sorry i don't i passed the reduction drive along to ES member Danny Mayes, Mr Recumpence would
be able to tellz you though i'm sure

KiM

 

[etard]

A little progress today, got the sprocket bolt pattern spot on and tapped. My first try was horrible, then I realized I could cut a small indent around the outer area where the sprocket mounts to. By making a lip for the inside of the sprocket I could then be sure the sprocket was centered, clamp it, and drill the holes through the sprocket. It worked great and now I need to do the same for the disc brake bolt pattern using the inside of a brake disc. I also found I larger motor pulley, not sure it is GT2 like the belt is, but it's close enough for jazz methinks.

 

[etard]

Sprocket adapters are hard to make! Well, not so hard as time consuming. Here is the adapter all tapped and drilled, I'm now waiting on some rims from Matt so that I can lace up this hub to figure out the sprocket offset necesary to clear the tire. I may not need any offset, if so I might attempt to cut this chunk of aluminum in half so that I can have two. Time to move on to the jackshaft...

 

[Danny Mayes]

I can't tell you the reduction cause i don't know what sprocket was on the motor. I can tell you the driven sprocket was 48 tooth.

My 2cents Etard, you can put an idler next to your motor pulley and get more wrap on it. Every extra tooth you get wrapped to that pulley increases it's ability to transmit power. Might get you buy without new belts and pulleys...

 

[etard]

Thanks Danny, I may have a go at the idler, otherwise, I will try this 30 tooth pulley. I don't really need much first stage reduction as I am going with #219 chain final drive so maybe a 2:1 belt drive will be plenty. Still not sure on the motor KV I will be using, if I go with this 180KV motor I will have to invest in an HV160 to keep the rpm's low and still get power.

 

[RWP]

Cool build etard. Was thinking of something like it myself...at least adding halls to the 130Kv motor and running it at 72V with a Lyen controller. The bike would be different though.
Do you think we are ever going to see any more of the Turnigy 80-100 and 80-85 motors?

With that much torque, you will probably need to go with 20 or 25mm wide belt. That 15mm wide belt will probably skip. I have found 15mm wide belts tend to skip above 5kw or so (not sure the NM torque, so this is a loose number). Or you could move to a Gates Polychain or Contitech Syncromesh belt in the same 15mm width. They are the same pitch, but much tougher material. Personally, I would move to a 20mm or 25mm width. I agree with the comments above. It is good to see a new build from you on the forum! Matt

Matt, where are the 20mm and 25mm pulleys coming from?

 

[recumpence]

Those pulleys would be coming from me. I have them made to my spec. :wink:

My primary pulley supplier is Pfeifer Industries. However, their production prices are really high on some stuff and reasonable on other stuff. So, I have them make the larger pulleys and I have another shop in the area make the smaller ones. There is a huge difference in price on the smaller pulleys from one shop to another.

I have found that motors of this torque level require at least 20mm of width to survive and 25mm gives a bit of headroom. Of course a wide belt affects the Q-factor and drops the efficiency a tiny bit.

Matt

 

[Arlo1]

Excited to see how this works for you.

 

[etard]

Roy,
Good to see you back in the game. I'm interested to see your latest build, is there a thread somewhere?

You may have missed this thread, it has some alternative sources for the same motor. I would suggest ordering one and having it sent to Thud for hall sensor mounting and rewinding.

Edit: ( forgot to post link)

http://endless-sphere.com/forums/viewtopic.php?f=28&t=31019&hilit=80+100+alternative

Matt,
I'm hoping the 15 mm belt holds up with a 30 tooth to 60 tooth setup, and maybe even an idler added to give more wrap as Danny suggested. If it doesn't I guess I will be pitting an order in for a proper setup from you.

 

[Thud]

#25 never skips

 

[recumpence]

E,

Yes, a 30 tooth pulley shoud do the trick. I run 30 tooth to 30 tooth 15mm wide belts when I tie two 3220s together.

Matt

 

[RWP]

Those pulleys would be coming from me. I have them made to my spec. :wink: Matt

Thanks for specking all this stuff out for us! How much are 72+/- by ½" to 1" bore and a 20 +/- x 10-12 or 3/8" bore pulleys? And where do you suggest I get belts?
Thanks!