For those of you who have spent considerable time on both touring and mountain bikes, which do you consider gives you the better cardio/overall workout? (and, obviously why...?)
I'm basically referring to non-trail type biking terrain but, moreover "street" or road terrain that includes flats and inclines.
If you feel there are other factors involved, I'd like to hear your thoughts on that too.

Thanks...

MHO is that mountain biking is a better workout - much more variable in both aerobic and muscular challenges over a 1-hour period, you get more work-recover-work cycles in there. Plus, the bike is typically heavier, tires much knobbier and softer, riding surfaces much less smooth - it's harder work just making it go.

There is no question that road riding allows for a better workout. You can modify and create different workout conditions far better on road than off.

Nobody trains for the MTB cup circuit on their MTB bikes, they ride road and then do techical workouts on their MTB for handling.

Since you're only considering flats and non-trail situations, I would think the intensity of the workout would solely rest with the operator. Granted, you can obviously go faster with less "gas" on a light, low friction road bike than you can on a mountain bike.

My experience with mountain bikes is that when used on trail, they are a more complete workout than a road bike. But that's on trail. You get a lot of upper body work on a technical trail (jumping logs, keeping your balance, climbing very short super steep hills).

I have had both bikes for about a decade. I've been using the mountain bike almost exclusively during that time. Since I recently started commuting to work on a bike, the road bike all of a sudden is looking a lot more attractive. It takes me 50 minutes to ride to my office (12 miles away) on my mountain bike, using somewhat slick tires. I'm thinking the road bike could lop off 10 - 15 minutes. We'll see.

-em

If you want the best workout in say, an hour or less, definitely go with the MTB on some bumpy hilly trail. Until I got one, I imagined myself gliding up hiking trails on wheels - what a shock to find out that pedaling up a bumpy incline is HARD WORK. Between keeping both tires down, and keeping the momentum going, it's a significant challenge.

Unfortunately most of us don't live so close to good off-road riding terrain, so getting that one hour ride may involve a second hour or more, in the car.

OTOH, if you want to get a longer, fat-burning workout that's as close as your back door, there's nothing like a road bike. Early AM rides when the roads aren't too busy, the wind in your face, miles slipping by...that's what skinny tires and an aerodynamic bike are for. I laugh when I see people hammering away on the roads on their MTB's, doing MAYBE 18 MPH, knobby tires singing...

But in the end, whatever makes you happy.

I love the early morning rides Mike describes, too. Get out and watch the sunrise. I get to watch it come up across the water from Orchard Beach.
I ride my mountain bike on paved bike paths to the beach then pedal across the SAND! Talk about expending lots of energy - I am pretty pooped after that 90-minute morning ride.
And those nubby tires are great on the snow In winter.......

I think the underlying theme is the same: if you want a workout, it all depends on how much you push yourself in either medium. As Murph points out, if you want fat-burning vs. aerobic, etc, you need to figure out your heartrate ranges and train within those. The truth is you can get a hard workout with both and an easy workout with both. The railtrail in NP is an easy MTB workout, but biking over the ridge on an ultralight carbon fiber bike is tough. The reverse is also true. If it's a workout you seek, then you should examine your overall objectives, the availablity of tough trails vs. good hilly rides and then buy what's appropriate. Personally, I'd never buy any kind of hybrid because you cut yourself short in both media. For street riding I moved to MTB exclusively from road exclusively about 5 years ago and haven't looked back.

Here are some sources (quality unknown) for heartrate training:

http://www.ultracycling.com/training/heart_rate_training_zones.html

http://www.runnersworld.co.uk/news/article.asp?UAN=176 (applies to running, but principally the same).

http://www.brianmac.demon.co.uk/articles/scni5a9.htm (caution: pop-ups!!).

http://www.heartmonitors.com/general_training.html

Oh yes, indeedy, there is plenty of cleaning to be done after a trip across the sand. Enough grit sticks to my sweating legs, so the oily bike parts really picks up the stuff.
Naturally, the bike gets cleaned first.

Sorry for resurrecting a 3-month old thread, but I'm gonna' take the plunge and buy a touring bike (my area really does not have terrain suitable for a mountain bike).

So, for you touring aficionados out there...any type/manufacturer, etc. recommendations for good touring bikes under $1,000?

Thanks...