Cyclometers

It isn't stand-alone, but the Sigma Sport BC1400 (older model, ~$20 on ebay) has an optional cadence accessory. The normal cable isn't long enough so you need the optional extended accessory to attach to the rear wheel. I use it no problem with my trainer. It is a full function computer so you can probably detach your other one? Some of the newer Sigmas have wireless hookups so a rear mount is easy however you still need to attach the wired accessory for the cadence. Be careful as only the top model has the cadence ability w/ accessory. Hope that helps.

I just bought a Cat Eye Astrale from my local bike shop for $39. You probably could get it cheaper on-line. It has cadence built-in, but you have to install the cadence option on the bike/attach it to the crank somehow. I'm not sure, I had them do it.

Cateye products are great and I have owned nothing but their products for my road and mountain bikes.

Thanks folks.....
I found a Cat Eye Astrale @ perfomancebike.com for $19.99.
Ordered it and will see how it goes.

Thanx for all the input.