CHAIN DRIVE COUNTER

Here is a counter I cobbled up this week. It’s a chain-drive unit. The components were bought on the internet.





At middle left are Delrin gears and chain obtained from:
http://www.robotobjects.com/scripts/prodList.asp?idCategory=42

I bought the white nylon spacer washer at a hardware store.

I used the counter from an old Jones counter. As shown it is on the right side of the bike and it rotates backwards. A proper counter will mount on the left and will increase counts as the bike rolls forward.

I ordered a new counter with proper rotation (model 075845.001) from:

http://www.veeder-rootcounters.com/uploadedFiles/Downloads/7458_7461_Spec.pdf

I have not got it yet. When I do I will have a neater job. The bracket needs neatening too. However, as it stands it works. I have no idea of its longevity, but will report as I learn.

The counter was about $45, the gears and chain about $10. The chain has no master link. You just snap together the length you need. The big gear has 40 teeth, the small gear has 15. With the ten digits per revolution built into the counter the unit displays 26.6666.... counts per revolution of the wheel. Other ratios are available to suit individual taste.

I don’t know how to make this a universal application. I had to shop around to find gearing that would fit within the geometry of my wheel and fork. I had to cut away the central hub of the Delrin gear so it would fit around the inner bearing nut on my wheel. The gear and spacer are loosely held in place by the outer bearing nut.

I offer this just for what it may be worth. You can download a movie of it working at:

Counter Movie

Click on "CounterMovie.mpg"

This message has been edited. Last edited by: Pete Riegel,

I suppose there's a small degree of precision gained over the standard JO wheel/gear arrangement, but I'm a little concerned about the durability of the chain. Particularly in the middle of a measurement.

Maybe I've just seen too many episodes of Junkyard Wars, where it's ALWAYS the chain drive that fails, but the standard arrangement is pretty bulletproof.

What's the drive ratio? Does it yield a nice even constant?

I didn't make any particular effort to make the drive ratio exactly even. I was looking for something more than 20 counts per revolution. Also, the available gear had to have a 1/8 inch bore - that's the shaft size on the counter.

There were only a few options that fit well into the available space, so I picked one that worked and gave it a shot.

As for durability, I expect the thing to last well over a hundred miles, as there is virtually no load at all on the chain.

But time will tell. It will certainly wear out - the only question is when. With chain at $6.00 per foot it's not a big deal to replace when it starts getting some slack in it.

CHAIN DRIVEN COUNTER – FINAL ASSEMBLY

I received the Veeder-Root counter from Danaher yesterday. Today I put together the final version. See below.



It’s mounted on the left side of the bike, and counts increase as the bike rolls forward. The bracket is made from light-gauge aluminum, cut to size with tin snips. There is a slot where it mounts to the axle to permit forward-backward movement to get the chain just right fore and aft. Side-to-side positioning was achieved by bending the bracket. The chain is adjusted so that there is a little bit of slack at all times, which eliminates any tension beyond what is needed to rotate the counter. I have ridden it about 5 miles so far with no noticeable aggravations. I think it’s now in its final configuration, at least until another Eureka moment arrives.

The constant appears to be about 20,000 counts per mile, which means it will roll over every 5 miles.

A good test for the thing will be a ride on some brick pavement. We have a few brick streets in Columbus, and they are boneshakers.

This message has been edited. Last edited by: Pete Riegel,

CHAIN DRIVEN COUNTER 3.0

The bracket on 2.0 seemed flimsy so I made one that’s more rigid.

Counter Update

June 7 - 32 km covered so far without a glitch.
June 13 - Now 50 km. No sign of wear.
June 19 - 102 km and still rolling.
July 2 - 152 km. Still like new.
July 9 - 201 km. So far, so good.
August 19 - 431 km. No problems.
September 10 - 530 km, going as new

This message has been edited. Last edited by: Pete Riegel,

Chain-Driven Counter Update

Yesterday the counter reached 530 km (329 miles). It shows no signs of wear so far, and continues to perform flawlessly. I believe it to be a viable alternative to other designs. The price is less than the JO, but requires a degree of mechanical ability to get it rigged.

This message has been edited. Last edited by: Pete Riegel,