GV27

Wheels yes - "sprung" weight, no. Now you're getting confused with cars. A lighter brake setup will help the suspension follow the road better resulting in better grip. Mass is mass. It takes a certain amount of energy to accelerate a given mass a a given rate. Doesn't make one hoot of difference whether that mass is bolted to the bike or not.

In fact I'd say the exact opposite. If I have a 20lb backpack then I have to hold it up as I ride along. If it's on the rack the bike holds it up. I can't fathom how weight that you have to move around every time you move has less impact than weight that you don't have to move.

Again - if I put 40lbs in a grocery cart it's easy to carry. 40lbs on my back is not. That's why things like wheelbarrows, grocery carts and bicycles were invented in the first place. Going back to the trailer - try riding 10miles with 100lbs in a trailer and then walking 10miles with it on your back. Think about it.

Really the only way to get significant gains is to put out more power with less aero drag. Trying to shave a couple of pounds off your bike is nothing compared to increasing your power output 5%.

spock

I've noticed that the hybrid has a front suspension. That will slow you down some, and not to mention the upright position. My trek 7000 had similar setup except for front suspension. I changed my saddle to road saddle and now it has flat handle bars with 32 tires instead of 35 and the difference is very noticeable.

rumrunn6

I'm gonna do a time trial. A selected 2 mile section of my commute and do it on all 3 bikes one after the other and time myself.

LesterOfPuppets

98% of hybrids are dogs, front suspension or not. Your road bike is a dog, too, so that's why you do best on your MTB.

My road bike is the fastest of my stable, but my hybrid (old Novara) is slower than either of my MTBs. I'd imagine some MTBs might be as fast as my road bike, mebbe a Ritchey P-21 with rigid fork and slicks...

hint, hint, Christmas is right around the corner... Hehehe.

SSSTANG

My MTB is an old ATX 870 with a rigid fork. For the riding I do, Rock Shox or whatever, would only be unneccessary weight. Next time I will probably use 1.50 tires.

slloth

I have yet to ride a MTB that is faster than any of the road bikes I have used for commuting. When it comes to speed I have never heard anyone recommend a MTB over a road bike for road use.

LesterOfPuppets

All depends on the road and mt. bikes in question. I'm guessing I could keep the Le Tour moving faster than the Giant, unless the Le Tour needs some maintenance...

rumrunn6

How come no one is saying anything about "geometry"? The only issues I've heard mention is wind resistance/posture; weight & maintenance. Doesn't a road bike let you push backwards a bit with your legs - whereas MB & hybrids force one to chop up and down with our legs. I mean doesn't the geometry of a road bike, even an old dog let me thrust more efficiently putting more horsepower to the wheels with less absorbed by the transmission. (sorry for the 4x4 & dragster/muscle car metaphor)

rumrunn6

Thanks for the equation Sam!

JMRobertson

The fitness of the rider has much more to do with this discussion than people are working into their equations. A less fit cyclist wont have a measureable difference between different bikes. An athelete would be able to tell the difference a few pounds would make.

My advice to a commuter is to measure your performace in terms of comfort, not in terms of minutes.

chipcom 

So perhaps the difference is as much you as it is the bike. If you have to shift your body weight to shift gears, you are not properly positioned on the bike. If your weight is shifting around, you are loosing forward momentum.

Additionally, the extra 'time to shift' because of friction shifting could be minor, but the 'timing of the shift' might be more significant. I note the difference myself between my road bikes with brifters and touring bike with barcons...with the brifters I shift more often, timed to keep my cadence steady, while with the barcons I tend to stay in the same gear longer before shifting...and usually shift earlier or later than what would be optimal.

Finally, there are way too many other factors that need to be considered, including weight, rolling weight, rolling resistance, fitness, traffic, lights, wind, temperature, mood, road conditions, etc. You are not exactly comparing apples to apples here.

ghettocruiser

On open roads my road bike is several km/hr faster, even with dedicated road wheels on the MTB.

In the city, the picture gets fuzzier. Although my fastest commute ever has been on my road bike (one time event) my average commute on the mountain bike is less than the road bike.

dynaryder

Get a digital fish scale and hang the bike off it. I picked one up for like $20-25 at a sporting goods store and find it comes in very handy. When I swapped last year's winter tires(Specialized Crossroads) for the same size Marathon Supremes,I weighed the tires and was amazed to find I'd cut about 1.25 lbs of weight off the bike(not to mention the spinning mass off my wheels). Also comes in handy for estimating shipping for stuff I'm eBaying.

dynaryder

FYI,hybrid does not always mean comfort bike. I would never commute on my full-carbon road bike.

T-Hussy

My warm weather commuter is a 91' specialized epic, full carbon with aluminum lugs(first generation carbon frame). Ultra fast commuter, helped my buddy remodel his house and got it for free. I dont regret commuting on it, Im super nice to it. Riding a nice bike when the weather is warm adds a lot of enjoyment to my commute and helps me stick with it even when its friday, my legs are whipped and a slight hangover lingers. My winter ride, 90' rock hopper, is my beater-bike.

tjspiel

I'm not saying that it's preferable to carry any amount of weight on your person instead of having it on the bike. I routinely carry 5lbs of stuff in my messenger bag. Over the 7 miles to work I barely notice it's there, but if I were to add five pounds to the back of my bike, I'd bet I'd notice immediately in the way it handled.

You may not agree but I'm pretty sure "unsprung" vs "sprung" applies to bikes, motorcycles and cars. I've got a good example. There's a wooden bridge I travel over every day. The faster I go, the more chatter I experience. If raise my butt off the seat a bit and allow the bike to rise and fall underneath me, - effectively reducing the unsprung weight, the bike follows the contours of the wooden slats better and there's less chatter. It's less annoying and I go faster. On the other hand any weight on the bike is dead weight.

Accelerating in a straight line on a smooth surface, mass is mass, but cycling isn't all accelerating in straight lines on smooth surfaces.

I do agree that at some point adding weight on your person instead of putting it on the bike creates fatigue and discomfort which ultimately will slow you down.

edit: I also agree that aerodynamics can be more important than weight. Often the penalty you pay for a bit of extra weight can be more than be made up for if in the process it improves your aerodynamics.

rumrunn6

Just got some pics of the old MTB. The tires are super wide slicks, easily 2". MAX pressure 65 lbs. Don't know for sure what brand.

Anogar

There are a lot of things to keep in mind; gearing, weight, how well maintained the two bikes are, how well they fit you, etc. Gearing can have a huge difference -- if the road bike doesn't have proper gearing for your commute but the mountain bike does, I'm not surprised at all that you find the MTB to be the faster ride. The road bike could also be in a questionable state of repair -- perhaps the chain line is bad, which saps energy, or the bottom bracket bearings are rusted and in bad shape, or lacking grease, etc...

There are a ton of factors -- just the fact that it's a road bike isn't going to make it faster than every single mountain bike.

rumrunn6

Turns out the MTB is an All TERRA GT

slcbob

I had relative improvements very similar to these. Fortunately, no wreck on the slicks. Lopped some off the MTB time by putting in a rigid fork, too. Still, on a road bike about 10% better than the MTB.

Concur that weight is over-rated. I'm not doing big hills, and the 10lbs difference matters but not that much.

I'm convinced that the money makers are:
a) general stiffness, power transfer, etc.
b) (big one) aero. Others dispute the road vs. MTB aero, but I think if you're not more aero on the road bike then one or both of them are set up wrong.
c) that great day, hit every light, got a little draft, tailwind, feeling manly that day, etc. etc. when everything went your way. That's good for 5 or 10%, too.

I don't know what a hybrid is anymore, so I won't touch that.