Well, it wouldn't be easy to take off frequently, but the Cateye Astrale works off the back wheel. It's only $19.99 at Performance (http://www.performancebike.com/.../Profile.cfm?SKU=569).

I've had mine for almost a year and I love it!

Dave,
No way to just attach the sensors, letting the wires hang, and use it only for indoor training? I appreciate your idea, and I know the easiest thing would be to install the Astrale full-time, I just love the wireless for outdoor riding.
Thanks again,
Tim

Yeah, you could let the wires hang and just unscrew the sensors, but the magnet on the crankarm would be tricky. You'd either have to leave it on all the time, cut a zip-tie everytime you wanted to take it off, or rig up a way to affix it that you could undo easily. Maybe a garbage bag tie? It could work, though.

I'm heading home from work now, so I'll take a look at my setup and give you a better suggestion in the morning.

Why do you need to know that anyway? Why not ride for time and HR (or RPE)?

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clm
Nashville, TN
https://twitter.com/ironclm | http://ironclm.typepad.com

Dave, thanks for looking into it.
Cathy, what is RPE? You are right, I can ride for time and use a heart rate monitor which I actually just inherited from my brother. While I am not gung-ho about finding a way to check cadence, I am interested in knowing speed and avg. speed. Any other ideas?
Thanks,
Tim

RPE=rate of perceived exertion.

I would keep looking for a way to rig the rear tire sensor, though. RPE is nice, but riding a trainer can be boring. I find the more data I have to evaluate, the more distracted I am and therefore the longer I'll end up riding.

Mr. Mike,
I agree about the more info the easier it is to not get bored.
Rigging the rear wheel does indeed sound like it might be the best solution. Cadence would be great, but like I said before, speed and avg. speed is what I am really interested in. That sort of stuff that can be great motivators/markers for having a hard workout in front of the TV watching taped TDF Stages.
Thanks to all, and please keep any more ideas coming.
Tim

Why would you want to know speed on an indoor trainer? It has no relevance to anything. I can sustain 30 mph indoors if I'm not pushing my 200 lb. body down the road. Its a different story when I'm actually moving. The RPMs of your bike's wheels is only relevant in relation to movement, weight and incline (or decline). MPH indoors has no real value.

Duration, cadence, heart rate and RPE; They have value.

Charlie,
Thanks for the insight. Duration and heart rate I can do easily, and maybe rig cadence using the Astrale temporarily on indoor workouts. But how do I figure out RPE?

 There's really nothing to figure out. Just assign a level or number to your misery level. 1-3 is going easy..

4-7 is a moderate effort.. 8-10 is sheer pain.

RPE: Nothing to figure. Using the Borg scale, it ranges from 6-20. Info here: http://www.undergrad.ahs.uwaterloo.ca/...g%20RPE%20Scale.html

For cadence? Ride along with the Tour and count your own cadence ever so often. I've found spinning classes are also good for learning cadence. I can now pretty much hit whatever cadence number you want.

For the trainer: I can't watch movies or TV, but I do watch the Tour (1989, 1999, 2000, 2001, 2002), Paris-Roubaix, multiple Ironman tapes (lots of Kona, NZ 01-02-03, Cali 00), Alcatraz and whatever else I have.

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clm
Nashville, TN
https://twitter.com/ironclm | http://ironclm.typepad.com

The new Cateye Astrale has a short cable for the speed sensor - only to be mounted on front wheel.

Sigma 1400 does also have a short cable for the speed sensor, but the Sigma cables can easily be extended. Mount the speed sensor on rear wheel. (I do this permanently - since I have to get the candence cable to the BB, it's much cleaner to let the speed cable follow the same route.)

The only trouble with Sigma 1400 is that it's CRAP - only lasting a few months. (The other, cheaper Sigma products lasts for years. Try the new Sigma 1600.

My last setup is Cateye Astrale using Sigma cables - works perfect, but a bit tricky to install.

Perhaps this isn't a great idea for an indoor trainer, because your sweat will get on the computer, but, I mount my wireless computer on the top tube and the speed sensor on the seat-stay...it keeps the front-end cleaner, and my knees don't hit the computer. If you really want the information, a cheap rear-mounted one might be your best bet.

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

Okay, looking at my setup last night, it shouldn't take you more than a couple of minutes to setup/take down. Three screws to undo (computer, cadence sensor and speed sensor) and the wires pull taut enough that they wouldn't get in the way. Like I said before, the only question is whether to leave the cadence magnet on the crank all the time or secure it with a twist tie or something else that can be easily setup/undone.

Two other things:

1) The Astrale that I use and that is on sale at Performance is the old model with the long wires for rear-wheel mounting.

2) I never use the speed function on the trainer. As someone mentioned, it's virtually worthless in that setting. I use the cadence feature exclusively, along with my HRM, and mark down the ride distance in my log for comparison purposes.

Hope this helps...

Hey Tim!

I think once you get on the trainer, you'll find that speed doesn't meet a damn thing on an indoor trainer. The model I have lets me change the resistance, so what exactly does it mean if I'm going 10 mph using my 39/23 ratio on setting 5, or 25 mph using my 53/13 on setting 1? I'm going 85-90 rpms in either case, and my heart rate is about the same. Bottom line: Because the resistance of the indoor trainer is nothing like the resistance of riding on the road, the speed measurement is meaningless. In fact, in terms of building raw fitness, speed measurement on the road isn't all that meaningful either when you consider hills, wind, pacelining, etc.

I've found that for a given level of exertion, I need to use a lower ratio (bigger rear gear) on the trainer than on the road -- which means the trainer will help me build stronger legs. In order to figure out how to get the best results from the trainer I bought a book called "Smart Cycling" by Arnie Baker, which includes a 12 week indoor trainer workout program. Others can probably suggest other, maybe better, books. His workouts focus on increasing cadence, increasing leg strength using individual leg workouts, and intervals.

Baker's book has specific gear ratios for the workouts, but I found I wasn't strong enough to use the suggested ratios. I used RPE to try to figure out the right gear ratio for the indoor trainer to match various kinds of efforts on the road. For example, I know about how hard I work to sustain 90 rpm on flat ground for 20 minutes, so I played around with different ratios and resistance settings until I got that right. Same for hill climbing. Once I had that dialed in (for me, it was 39/15) I would structure my workouts with specific times in specific ratios, for example 10 minutes in 39/14 followed by 5 minute recovery in 39/16. Or a 5 minute "hill" at 53/15 @ 70 rpm, or a 2 minute "sprint" at 53/17 @ 85 rpm. Following baker's suggestions, I would also try to set it in 39/17 and do 1 minute at 80 rpm, then 85, 90, 95, 100, 105, 110, and 115, then drop back to 80 rpm @39/19 to recover for a few minutes, then do it again at 39/16. I also did 3 reps on each leg individually of 2 minutes at 50 rpm at 39/15.

In any event, as long as your computer gives you cadence and elapsed time, you'll be all set.

Lee

I did the same thing, except I took my wired computer and modified it to work with the rear wheel so I could have all those numbers. But as everybody else has mentioned, the numbers don't mean jack. I can hop on the trainer at the max resistance setting and I can only average around 12mph or so for any meaningful amount of time, which can be quite the downer, until I found a wattage chart for my trainer and found out that 12mph at that setting was around 225-250watts of power output.

Andrew

I'm not sure why speed would be considered "useless" on an indoor trainer, granted the numbers may not have any bearing on the speed that you would see on the road, but it does have a valid purpose in my indoor workouts. For example I use a wind trainer and during interval work I know that I will use a specific gear and and try to maintain a certain pace. Since the load from the fans is constant at a given speed, I have a repeatable way of monitoring my fitness and seeing how it increases or decreases as the season progresses. I know its not as good as a power meter (that can be a thread on its own), but its the best way that I can afford. I don't consider that as useless.

By the way I have an Astrale with short wires and all I did was to cut the wires and solder in a section of wire that gave me enough length to mount the sensor on the chain stay.

In response to Burgerdp, that was my initial thinking. Speed might be helpful to know (and avg. speed) not necessarily as an indication of my actual sped, but more so to use as a training benchmark to adjust and record.
Thank you for the website Cathy. And to all who contributed. I like the idea of the cheaper Astrale on sale to simply take on and off. Leaving the cadence sensor on permanently sounds fine. Thanks for looking into it Dave.
And Lee, thanks man! Nice to hear from you on the forum.
Tim