lukathonic

I know that touring bikes aren't built for speed as much as durability/comfort/stability, but I have a question about speed.

I just picked up a Novara Randonee during the 20% off member sale - I really like the feel and I'm generally happy with the components (except the saddle and pedals)

My old bike is an older stumpjumper converted for commuting (continental contact tires and bar ends), and I was expecting a speed increase going to drops and skinnier tires on the randonee. But I'm averaging almost exactly the same speed on my 5 mile commute (16-17 mph)

I have considered it might be the tires on the randonee, with have a top pressure of 65 psi and more tread than the slicks on my mtb. Bike weight is comparable.

Do you think that as I get used to the riding position my speed will increase, or should I not expect a speed increase? Thanks for your help.

Machka 

That sounds about right. A lot of people think that a road-style bicycle is so much faster than a mountain-style bike, but there really isn't that much difference ... especially if, as you say, the bikes weigh the same, and you have slicks on your mtn bike and tires with more tread on the new road bike.

fthomas

I have a 3 yr old Randonee and found it less tiring over long distance vs. the mountain bike with slicks. Speed same. Two different tools for the job. Put a load on each and I don't think you would be disappointed. It is proven contrary to popular belief that a 26" touring bike is just as fast as the 700C sister

fthomas

I have a 3 yr old Randonee and found it less tiring over long distance vs. the mountain bike with slicks. Speed same. Two different tools for the job. Put a load on each and I don't think you would be disappointed. It is proven contrary to popular belief that a 26" touring bike is just as fast as the 700C sister

58Kogswell

I agree with the statements of the earlier posters and I am not trying to second guess you but don't forget that you are accustomed to riding that same commute route at a certain speed, based on a certain level of effort, every time you ride it. It is not easy to change to give the bike more power than you were used to. If you use about the same effort (amount of work) as you have in the past you will end up at about the same speed. You said both bikes are set up for pavement so don't expect a whole lot of difference. Modern bikes are so efficient that merely changing the geometry, tires, etc. with no change in power input will not make a big difference. The rolling resistance and the internal power loss to friction, etc. are about the same. Get a 16 pound carbon bike with 23mm high pressure tires and you could probably notice a difference. Only don't do that.

seeker333

I think your average speed will drop significantly below 16-17 mph once you add a 30-60lb payload, and try to carry this load for 10X or more distance than your current daily commute. Then you'll just be wishing you could go as fast as you could on your unloaded MTB.

Simple, huh?

BigAura

Overall weight is always an issue. Tire pressure is also important. The diameter of a wheel is the least significant of these. Your Rondonee is probably not much lighter than your mountain bike. I would definitely upgrade to a higher pressure tire.

If you’re planning on touring watch the overall weight which includes the bike, equipment, supplies, and rider. Less weight ALWAYS equals more speed or distance for the same energy.

foamy

Slick, high(er) pressure tires will make a difference.

sykerocker 

You're speed is already quite good - I'm normally averaging 14-15mph on my tourers and normally budget myself 12mph for the day on a trip, counting stops, meal breaks, nature breaks, etc.

john bono

I think you are underinflating your tires. I keep mine at 75 psi.

Oh, and as for performance, it isn't quite as fast as my Sequoia, but it's plenty fast enough for a commute.

m_yates

You will notice a speed difference in a headwind if you use the drops. I have been commuting on a touring bike (Windsor tourist) 22.6 miles round trip each day. I used to do this commute on an old mountain bike. The drop bars make a big difference for me in a headwind. I was also able to get my backpack off my back by using racks and panniers to carry my stuff.

robow

I have a mountain bike that I've converted to a touring bike and it weighs in at 24 lbs without racks and such. I just finished building a carbon fiber road bike this month and it weighs in at 19 lbs, (yea, the triple crank, large count spoke wheels, and brooks make it heavier than it could have been). I average about 1.5 mph faster on the road bike and that's it. The wheel weight probably accounts for most of the difference.

Lake_Tom

The Novara Randonee and the Stumpjumper may have tyres with vastly different rolling resistance. For low rolling resistance, you want tyres with a high "thread count" and a supple carcass to roll smoothly over bumps and pebbles instead of being jounced up and losing energy.

seeker333

You get those 1.5 mph >90% from drop bars and an advantageous aerodynamic position.

Wind drag increases as a square (area) of your speed. It takes ~4X as much energy to pedal at 20mph as it does at 10mph.

Panniers and other luggage increase cross sectional area, which is pretty much directly proportional to drag.

Behind drag, your next speed killer is those ever popular 800-900g Schwable tires. Heavy tires, tubes, rims, spokes - in that order.

Actual weight of bike and gear is the least significant factor on flat ground, but begins to become a factor as the climbing grade increases.

All of this explains why most bicycle tourists average 10-12mph - and half that speed when the wind is blowing.

robow

"You get those 1.5 mph >90% from drop bars and an advantageous aerodynamic position."

For most you would be correct but not likely in my case since I'm almost never in my drops and surprisingly, I have both bikes set up where my posture is very similar so not likely a large aero advantage on the roadie.

kpfeif

In that case, you probably should have spent $12 on slicks for your mountain bike and saved the several grand on the carbon roadie!

robow

My wife said the same thing

lukathonic

Thanks for the comments everyone.

Skewer

Wider tires actually have lower rolling resistance than narrower tires of the equivalent make and model at the same pressure. At some point, however, a point that is likely much faster than most of us are going, aerodynamic drag trumps rolling resistance in importance for tires, and hence skinnier, more aero tires are more popular with professional racers.

<<Narrower tires of 23 mm and less, decrease rolling performance and require higher inflation pressures, which adversely effect riding comfort. Gains are made in aerodynamics requiring less energy for maintaining speeds exceeding 40 km/h or 25 mph.[/SIZE]>>
https://www.rouesartisanales.com/article-1503651.html

Also, for steadily cruising fast on the flats, a heavy rear wheel is not a bad thing. It is easier to hold your momentum with more wheel weight at high speeds. Of course if you are constantly decelerating and accelerating, or climbing, all bets are off. But Sosenka used a whopping seven pound rear wheel when he set the world one hour distance record a few years ago, traveling 49.7km in one hour.

<<In his attempt, Sosenka was using a 3.2 kg wheel and 190 mm cranks, with his bike weighing a total of 9.8 kg. The reason for the heavy wheel was that although it was harder to get up to speed, it was easy to maintain it.>>

https://www.cyclingnews.com/news/?id=...l05/jul19news6

Lake_Tom

Cool story with the record setting cyclist.

Notwithstanding the heavy rear wheel example, do you think that "change of direction" counts as acceleration? The cyclist is obviously losing the momentum in the X direction when he changes to the Y direction (with a 90 degree change of direction meaning all the momentum is lost). There is stored kinetic energy in the wheels (angular momentum), but I don't think that the energy of the bike is there. My hunch is that the kinetic energy of the bicycle is lost as the tyres make the turn. It turns into heat.

climbhoser

I commuted on a MTB with knobbies for a few weeks before I got my roadie. Thought the roadie would be WAY faster, but the first couple of times I rode it my times were slower

I had become so accustomed to the MTB that I wans't as efficient on the roadie.

The roadie is now only slightly faster, but the main difference is in how comfortable each is for me spinning long distances on pavement. The MTB geometry just isn't conducive to it, and my hamstrings get oddly sore.

The roadie feels comfy for all day stuff.

My$.02

Xanti Andia

Average speed might not be a good measure over a short commute. I ride a road bike and a mountainbike on city rides, I have a higher top speed on the road bike (23 mm tires versus 2.0 " knobbies), but on the moutainbike I have a better initial sprint out of the lights and pay less attention to potholes, overall my average speeds are similar.

skookum

A narrow tire is made to take a higher pressure, so why would you run them at the same pressure as a wide tire?

On the flats without a wind the main force you have to vercome is rolling resistance, up to about 15 mph where air resistance starts to have a bigger effect. A light wheel with a properly inflated narrow tire will have lower rolling resistance. In general rolling resistance decreases with increased pressure, but if you over inflate the tire you start to lose traction.

If you get up over 15mph then to get a really aerodynamic position you have to be on the drops, right down as low as you can go, but that is not a particularly safe position for commuting where youneed to be constantlyaware of traffic. Apparently the really low head down position of a triathlon bike has the same aerodynamic reistance as a recumbent, but a recumbent is more comfortable.

SRS

Here are some numbers derived from analyticcycling.com's formulas that illustrate points made in previous posts.

Hopefully, the following columns of data will display correctly on people's browsers.

Weight is in pounds (total - bike, person, gear), speed in mph, next four columns contain a front area decimal and hill grade, e.g., .5/0 is a frontal area of .5 square meters/0% hill grade. Values in the last 4 columns are in watts. All values use the same rolling resistance and are calculated with an air density equal to standard sea level. Higher density altitudes/elevations would result in slightly lower wattages. All wattage values use a no wind assumption. Though it is not an exact match, one can add the headwind component experienced to his/her speed to get an equivalent speed.

Weight Speed .5/0% .7/0% .5/3% .7/3%

200 10 30 35 149 154
200 15 70 89 249 268
200 20 137 185 380 424

250 10 34 39 183 188
250 15 76 95 300 318
250 20 145 193 447 491

As can be seen in the numbers and as mentioned by a previous poster, weight has little affect on wattage required whereas increased speed and hill grade have substantial affects on wattage required. Frontal area is in the middle of the pack regarding necessary wattage increases. Not surprisingly, as one's speed increases, a larger frontal area requires a larger increase in wattage required on a percentage basis.

If any one is able to cruise along at the lower right hand criteria I recommend you contact one of the ProTour team.

skookum

Here is the handy bicycle speed and power calculator, where you can change the variables and see how much difference it makes. Hours of fun. But I never can go as fast as the progam says I should.

https://www.kreuzotter.de/english/espeed.htm