In a pinch, sometimes you just need to fall back on the old ways. While this fits a few bikes the JR will not, I cannot attest to the durability. It mounts on the right side to avoid issues with disk brakes, but it reads sideways. It probably works ok, but I have not tested it. I cannot control the quality of the chassis. It will cost the same as the standard JR, but I lack the confidence and motivation to stock anymore than the 2 or 3 I purchased to experiment with. If it breaks, I'll work with you or provide you a link where you can buy the chassis directly.
In 1977 Pete Riegel designed and had manufactured an order of race pace computers. They sold at a modest rate – enough to barely break even. At one point he quit selling them because the advertising was costing more than the profit. The units sold for $2.50 each. You can read about the development of the computer at the URL below:
Here is a picture of the computer. It’s basically a special-purpose circular slide rule.
Say you want a shot at a three hour marathon. How fast should you be running a 10k?
A marathon, 26.219 miles, run in 180 minutes, requires a pace of 6.865 minutes per mile, or 6:52 minutes per mile.
Setting the “distance” arrow at “M” (for marathon) will show a performance factor of 712 opposite the 6:52 pace.
Now, setting the “distance” arrow at 10 km will show a pace of 6:11 (6.18) minutes per mile opposite the 712 performance factor. Since 10 km is 6.214 miles this pace will yield a finish time of 38.40 or 38:24.
The computer works over a range of 1 mile to 26.2 miles. Is it geeky? Absolutely. Does it work? Yes.
The computer may be ordered from Jonescounter.com until the stock runs out. Price is $4.00 per unit, postpaid. Any quantity may be ordered if ordered for shipping with a Jones Counter. For computer sales only, a minimum order of 10 units is required.
RIGHT-HAND JONES COUNTER (JR-5R)
In 2010 a right-hand version was made available to fit bicycles with disk brakes, 5-digit only. Due to lack of sales, the unit is no longer in production. My JR-5R has been personally ridden over 3,500 miles on terrain ranging from the baby-heads in the Appalachians, Slickrock in Utah, to the ashy slopes of Mt. St. Helens. The JR-5R used a mirror-image of the standard unit, which allows it to be installed on the right-side of the hub.
CHASSIS REPLACEMENT KIT:
If your old counter chassis has bent or broken for any reason it can be replaced quickly at low cost. Included in the chassis replacement kit ($29) are instructions on replacing the chassis, and the nuts & bolts you need to fix it. This will be the last chassis you need to purchase.
Contact Tom + Tina at:
The latest revision to the JR will be to include a brass extension to the tang.
This item is still in the testing and development stage but is intended to replace the wire used in the current version to provide a more elegant installation.
A pre-production sample can be provided for $200 for evaluation. Delivery TBD.