Skiptooth sprocket question

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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I had the good fortune of finding a pre war skiptooth 26" Schwinn DX cruiser at the dump the other day and as close as I can guess from reading up on it the year would be somewhere from 1940 to mid 40's. I'm been staring at it since figuring what to do with it since the frame and fork are really nice , the handlebar is in good condition and the seat just needs new leather and cleaning up. The DX was a budget model at the time, but still was a pretty cool bike. The tank is missing, fenders and chain guard as well. I sat an 80cc HT in the frame and it is tight, but I think with a slant head it will fit. I think I'd like to keep the bike pretty much original without going crazy with a real restoration and will be on the lookout for a chain guard, rear rack and tank if I can afford it. Here's where my question is regarding the pedal crank sprocket. It is a skip tooth and the wheels I intend to put on it are going to be modern heavy duty rims from bikeworldusa, 26 by 2.125. The sprocket is pretty cool and is called a "sweetheart" due to the heart shaped cutouts. Since it is a kind of signature thing with this model it would be nice to keep the sprocket even if I change the crank to something shorter to accommodate the engine clearance issues.Now, to the point... does anyone know if you can use a regular cruiser chain with a skip tooth sprocket and a wheel sprocket which is not skip tooth? I'm guessing not, but hoping you can. Or can I use a skip tooth chain if it will work with the wheel sprocket? Does anyone know? Since this will be a motorbicycle I don't anticipate a whole lot of pedaling, but it still has to be able to be pedaled.
Silverbear
 

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wildemere

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Feb 12, 2008
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If its 1" pitch then 1/2" pitch chain will work without issues.

Width would be your only problem.

I an recall old fixed wheel track bikes having these chainwheels for weight saving reasons. The chain was normal as was the rear cog.
 

GearNut

Active Member
Aug 19, 2009
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I have asked about using the skip tooth chains at a local antique bicycle store.
What I learned was:
If you can get ahold of a rear sprocket that has an even number of teeth, you can file down every other tooth and keep the skip tooth chain if you want to.
Standard bicycle chain is 1/2 pitch. Skiptooth chains are also known as "inch pinch" chains.
Do the math.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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i know from experience that a regular 1/2" pitch chain will NOT work with a skip tooth (1" pitch) sprocket. two totally different animals. the skip tooth chain has two different links, alternating 1/2 link, then 1' link, repeating... a newer 1/2'' pitch chain will roll right off, jam up, or break.

i've been down this road before and i've tried just about everything imaginable.

here's some options for it that you're just gonna love...

the easiest thing to do, would be to buy a "newer" sweetheart sprocket with the conventional 1/2' pitch. you can get one here for 6.95. Pedals ~ Sprockets ~ Cranks

that way you can use a new chain, the new sprocket on your wheels, and everything would be nice and modern, and simple.
but who wants to take the easy way out?

so, the first thing you have to do is find a skip tooth, inch pitch chain. if there's one rusted to the bike already, you're in luck. soak it in oil for awhile.
if not, ebay always has them. they usually go for 50 bucks for an old stretched out one, to 100+ for NOS.

that's the easy part. it just takes money.

now, for the rear cog (sprocket).

i've done both of these on a bendix coaster brake, and they both worked.

the bendix cog has three nubs that slide into grooves in the hub, and then are held in by a snap ring.
you can find an old skiptooth cog with the same inner diameter to fit over the hub. find one with just a round hole, no nubs.
then, weld on three nubs to match the hub. install, and ride around.

this one's even more fun.

buy an extra rear cog to fit your bike, make sure it has an even number of teeth, then grind every other one off. make sure you quench it in water after each tooth, or whenever it gets really hot, so it doesn't warp.

the only problem with this method (besides the mess, the time, the P.I.T.A. factor,) is if your using an old chain, the new cog teeth might not get along with it, so you might have to do some extra grinding and filing of the teeth. but, inch pitch chains are remarkaby strong, and don't stretch anywhere near the amount as the newer 1/2'' ones do.

here's things that WON'T work.

-switching the guts from another hub into your new one (unless you find the "holy grail" hub that i never could.)

-inch pitch chain on 1/2" pitch sprocket, and vice versa.

-finding an old rear cog that matches the one on your new back wheel, and fits right on (another "philosopher's stone".)

i don't have the bikes i did this to, so sorry, i don't have pics.

but i do have a brand new 18 tooth (equal to a 36) WALD skiptooth front sprocket, inch pitch chain, and an 18 tooth bendix rear cog, which will soon be grinded down to a 9...

hope this helped.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
Thanks to all for your responses. Well, I'd say this doesn't look too promising. No, there was no chain with this bike. If I really wanted the sweetheart sprocket, as you say I could buy a new one with the proper number of teeth, or forget about it and use the sprocket from a post war Schwinn, which would at least be old, good quality and Schwinn. I do have one of those from a middleweight American. Nothing is ever simple, is it?
Silverbear
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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I just took a look at the auction results from that sweetheart sprocket and crank on eBay. It ended at $68.58! Incredible... I'm listing mine tonight and with any luck may fetch a similar inflated price. Pretty good from a free bike. That would just about cover new heavy duty rims.
Silverbear
 

Kevlarr

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Jul 22, 2009
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Saw an Elgin on ebay (I think, it was late last night) that someone had actually turned a regular sprocket into a skiptooth. Would have looked more convincing except it was just a blank sprocket, it definitely wasn't an inch pinch chain.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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i'm almost positive schwinn made a sweetheart sprocket after the skiptooth, modern style. i'll keep my eye out for ya.

did you say you ordered the wheelset from bikepartsusa? i just got mine. weinmann alloy rims, 12 guage stainless spokes, and shimano hubs. they're pretty good, the silver anodizing isn't that great, it's kinda cloudy, and there's a splice where the rim's put together, and the spokes don't seem to be seated all the way, although they're tight.

for the price, they can't be beat. and i've ridden on them for the last day and a half, probably 70 miles worth, and they're smooth. we'll see how they hold up.

oh, back to the skiptooth. last week i checked out ebay around 3 in the morning, and there was an NOS diamond inch pitch chain, buy it now, for 25 bucks. needless to say, it's mine. i got it yesterday.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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That's NOT a DX frame... it's a straight bar! (Panther, Hornet & such...)
On a DX, the middle bar has a slight upward curve to it.

It's a very nice find!!! Congrats. Keep the original paint!!!

It should be easy to find a skip tooth chain & rear sprocket for it.
 
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raven61

New Member
Sep 4, 2009
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One slight adjustment to this,
"make sure you quench it in water after each tooth"

quench it in oil, real smokey, but will help maintain the metal temper more.
r
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
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northeastern Minnesota
That's NOT a DX frame... it's a straight bar! (Panther, Hornet & such...)
On a DX, the middle bar has a slight upward curve to it.

It's a very nice find!!! Congrats. Keep the original paint!!!

It should be easy to find a skip tooth chain & rear sprocket for it.
Thanks for the information. I have a Schwinn book my brother gave me and I tried to find the bike in there. The paint scheme looked like those on the DX models, so I went from that. The serial number search didn't help since the records I found online start after that. Do you know of a good source for looking up the serial number to see just what it is and when it was made. I don't want to misrepresent the bike as something it isn't. Too late on the paint. I debated leaving it and decided there was too much rust. It has been stripped down, primed and is now black. I was looking to do the paint after the Schwinn Motorbike, since I like that and it has the same frame as the DX which I learn mine isn't. I did find a feather chain guard on eBay for not too much and that is on the way. I have redone the seat, just finished last evening. I stripped it down, wire brushed all the metal parts, primed and painted black, found the seat padding was one thickness of burlap to which I added two thicknesses of carpet padding foam. Then I covered it in black elk hide which I always have around for making moccasins. Looks nice and I suspect it is going to be very comfortable. After I do the chain guard the bike will be put away for tinkering with in the winter. I'm thinking about a behind the seat gas tank made from a smallish brass fire extinguisher. If not that, then a cylindrical aluminum one upholstered in black elk hide. I'm getting real tired of those peanut tanks. Do you know of a really good reference for the old Schwinns? In taking that bike apart I was very much impressed with how well it is made. The handlebars cleaned up very nicely as did the seat post. The seat post clamping hardware (don't remember what it is called) looked pretty dull and I didn't think it would clean up well at all... discovered it is not chrome, but I think nickle and it cleaned up beautifully. Cool. It is going to be a really nice looking bike. Here's a couple pictures of a Schwinn Motorbike. I really like the tank decal.
Silverbear
 

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
Those pics look like a Schwinn Autocycle.
Google Schwinn serial numbers... or just post the # & I'll look it up fer ya!
Under the crank are the numbers G387802
I hope you have something for me... thanks for taking the trouble to look it up. I appreciate it. I got the front caliper brake adapter on after drilling out the broken screw that holds the fender to the underside of the fork. Hassle, but it is done and the new chrome fender looks sharp against the black paint.
Fun. My 39 Elgin step through frame came today and looks really good. Nice bright work on it. It is much nicer than the beat up 1940 fenders, skirts and chain guard I already had which will finish it out. Lots of fussing with dings and such, besides a lot of paint stripping.... sighh. However, I set an engine into the frame and it is a plug in. Perfect fit. It is going to be different, all right.
Silverbear
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
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northeastern Minnesota
Serial # G387802... Your bike was made 10/14/1950.
Thank you for taking the trouble to look that up.
I have just posted photos of the bike in question as it looks now under Silverbear's American Flyer #2 in the Tavern forum. You are surely right that it is a straightbar frame, but I am still unconvinced that it is not a DX, since the grphics for the DX are just like mine (as shown in a Schwinn book I have). I'd rather think it was a Panther, of course.
Silverbear
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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As I said, the DX center bar has a slight curve in it; the straight bar is straight. ;)

I just looked at the other pics... It's definitely a straight bar frame! You should look around on line & find out what models were painted like that.
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
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northeastern Minnesota
As I said, the DX center bar has a slight curve in it; the straight bar is straight. ;)

I just looked at the other pics... It's definitely a straight bar frame! You should look around on line & find out what models were painted like that.
You're right; it isn't a DX. I'll be on the lookout. I doubt it was a panther or other high end model since I saw no evidence of a front springer, rear rack or any of that having ever been there. Whatever it is, I like the frame design. Thanks for helping me out with this. These old Schwinns are great, aren't they!
SB