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Bicycle Gear Calculator...stumped!

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Bicycle Gear Calculator...stumped!

Old 06-11-22, 09:37 AM
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67tony 
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Bicycle Gear Calculator...stumped!

I'd like to see those young urban guys try this single-speed beast!
Interestingly, when I open up their website (sillycycle.com), pics of frame and tubing tools cropped up.



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Old 06-11-22, 10:21 AM
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Wow! Trying for the world land speed record? How many teeth front and rear? Here I thought the 58T chainring that came with my first Sieger was big ... .


Almost all-orig. 1960 Capo Sieger
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Old 06-11-22, 10:31 AM
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Originally Posted by John E View Post
How many teeth front and rear?
Counting the teeth without the chain on them, then extrapolating, I'm guessing about 136 front teeth.
The rear looks normal, probably 11 or 12.
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Old 06-11-22, 11:13 AM
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Originally Posted by 67tony View Post
I'd like to see those young urban guys try this single-speed beast!
Interestingly, when I open up their website (sillycycle.com), pics of frame and tubing tools cropped up.


And it's a mid-70s Schwinn Varsity!
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Old 06-11-22, 12:34 PM
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It looks like someone might have made a new drive-side chainstay, in order to clear that giant chainring! That's a lot of dedication & effort for a Varsity!

It certainly reminds me of an earlier Schwinn that hit 108.92 mph....






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Old 06-12-22, 08:38 AM
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Yes, but the best part of that setup is the "crash helmet".
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Old 06-12-22, 11:53 AM
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^^^^^^ Fork's bent.
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Old 06-12-22, 12:08 PM
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Originally Posted by madpogue View Post
^^^^^^ Fork's bent.
the classic jokes just never get old.

but seriously... it took this long for me to notice that Alfred's bike looks pretty much like a standard "stayer" bike used in motorpaced track races. Even the helmet is from that activity.
For those not familiar with this rather unique activity, Cycling Weekly has a nice article on it:
https://www.cyclingweekly.com/news/l...r-bikes-316992

The change from motorpacing behind a motorcycle to a sprint(?) car isn't too huge, aside from that chainring and the magnitude of the potential injuries.

Steve in Peoria

Last edited by steelbikeguy; 06-12-22 at 07:18 PM. Reason: I can't type... or spell.
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Old 06-12-22, 07:07 PM
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Notice how the chainrings are nearly the same design. Whoever modified the Varsity certainly was paying tribute to the 1941 Paramount.
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Old 06-12-22, 07:22 PM
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Originally Posted by pastorbobnlnh View Post
Notice how the chainrings are nearly the same design. Whoever modified the Varsity certainly was paying tribute to the 1941 Paramount.
It would be interesting to hear the history of that Varsity and chainring!
There are distinct differences in the chainrings.. maybe the most important is that it is for a 1/2" pitch chain, while the original is using 1" pitch block chain (I'm fairly sure). There are some minor differences in hole patterns too, so it's not like someone just showed a machinist a photo of the original and said "make me a copy".

It still seems like a lot of work for a bike that almost certainly can't be ridden, IMHO, etc.

Steve in Peoria
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Old 06-12-22, 07:26 PM
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I really like the adjustable bar stems on the Capo and the Paramount.
Checking on the'Bay doesn't show any.

Does anyone know the model(s)?

Edit: Yowzers! I checked "adjustable racing stem" and they're not cheap 😮.

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Old 06-12-22, 08:11 PM
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Originally Posted by WGB View Post
I really like the adjustable bar stems on the Capo and the Paramount.
Checking on the'Bay doesn't show any.

Does anyone know the model(s)?

Edit: Yowzers! I checked "adjustable racing stem" and they're not cheap 😮.
My old Cyclo-Pedia catalog showed two models of adjustable stems by T.T.T., better known as 3TTT nowadays, and previously known as Ambrosio.



I always thought they were pretty interesting, and possibly useful when setting up a bike. Never bothered to actually buy one, though.

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Old 06-13-22, 12:01 PM
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Originally Posted by WGB View Post
I really like the adjustable bar stems on the Capo and the Paramount.
Checking on the'Bay doesn't show any.

Does anyone know the model(s)?

Edit: Yowzers! I checked "adjustable racing stem" and they're not cheap 😮.
Note that Major Taylor stems and the Schwinn adjust from the front. The OEM Ambrosio stem on one of my Capo Siegers adjusts from the rear.
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Bianchi: 1982 Campione d'Italia, S/N 1.M9914
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Old 06-13-22, 07:13 PM
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Originally Posted by steelbikeguy View Post
It looks like someone might have made a new drive-side chainstay, in order to clear that giant chainring! That's a lot of dedication & effort for a Varsity!

It certainly reminds me of an earlier Schwinn that hit 108.92 mph....






Steve in Peoria
That chainring appears to me to have considerably more than 57 teeth.
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Old 06-13-22, 08:20 PM
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Originally Posted by jonwvara View Post
That chainring appears to me to have considerably more than 57 teeth.
honestly, I can't count them, but since it is an inch pitch chain, the 57 teeth means a circumference of 57 inches.
The diameter would be 57/3.14, or 18 inches, or a radius of 9 inches. Assuming a crank length of 6.5 inches, the chainring looks like it could easily have a radius of 9 inches.

For those who aren't familiar with 1 inch pitch chains and chainrings, my old Cyclo-Pedia catalog shows some inch pitch track chainrings on the right side of this page....



I don't think I have a picture of a block chain that goes with these inch pitch rings, unfortunately.

edit: I do have this shot of a chain that isn't block chain, but is a roller chain with spacing that appears to replace block chain...




Steve in hot Peoria (and getting hotter)

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Old 06-13-22, 08:24 PM
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159 feet per second is equal to 108.4 mph!
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Old 06-14-22, 01:14 PM
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Originally Posted by steelbikeguy View Post
honestly, I can't count them, but since it is an inch pitch chain, the 57 teeth means a circumference of 57 inches.
The diameter would be 57/3.14, or 18 inches, or a radius of 9 inches. Assuming a crank length of 6.5 inches, the chainring looks like it could easily have a radius of 9 inches.
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That's what I get for commenting after seeing a tiny image on my phone--I had not noticed that it was 1-inch chain. But it still looks bigger than 57 teeth to me.
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Old 06-14-22, 02:00 PM
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Originally Posted by jonwvara View Post
That's what I get for commenting after seeing a tiny image on my phone--I had not noticed that it was 1-inch chain. But it still looks bigger than 57 teeth to me.
to be honest, I went back to the original image and realized that there is 1/4 of the chainring that is exposed, so I counted the teeth there. It's still a bit hard to see, but I came up with about 14 or 15, so the total of 57 teeth seems reasonable.

Here's a link to the full resolution image: https://live.staticflickr.com/4545/3...18b54_4k_d.jpg

It's interesting to see what they had to do to the chainstay to provide clearance for that giant chainring.

Steve in Peoria

oh... I should mention that I've seen this bike in person, while on RAGBRAI. Pretty impressive.


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Old 06-14-22, 08:09 PM
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Originally Posted by jonwvara View Post
That chainring appears to me to have considerably more than 57 teeth.
Ahhh- good catch- it's 57 metric teeth.
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Old 06-14-22, 08:53 PM
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Originally Posted by The Golden Boy View Post
Ahhh- good catch- it's 57 metric teeth.
Double it and add 30.....

Actually, to simplify on Steve's math, it's basically a skip-tooth chainring, so 57 teeth spaced at 1 inch would, in our 1/2-inch-chain world, equate to 114 teeth.

(I'm guessing the RAGBRAI photo was taken when the now-C&V van was "modern"?)
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Old 06-14-22, 09:04 PM
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Originally Posted by madpogue View Post
...
(I'm guessing the RAGBRAI photo was taken when the now-C&V van was "modern"?)
the photo was taken in 1991, on RAGBRAI 19. A little more than 30 years ago, so it probably qualifies as vintage.
In fact, it was so vintage that Schwinn was still in business! Good heavens.

Steve in Peoria
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Old 06-14-22, 09:12 PM
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Originally Posted by steelbikeguy View Post
the photo was taken in 1991, on RAGBRAI 19. A little more than 30 years ago, so it probably qualifies as vintage.
In fact, it was so vintage that Schwinn was still in business! Good heavens.

Steve in Peoria
Cool, and about what I expected time-wise. That lettering/branding of the word SCHWINN depicted on the van matches my stable of '89-'92s (eek, better not reveal how many....).
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Old 06-15-22, 01:26 PM
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Originally Posted by The Golden Boy View Post
Ahhh- good catch- it's 57 metric teeth.
Also, I hadn't realized the people were counting the teeth in base ten.
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