MTB-Road Bike conversion factor?

recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a general
rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

From some online sources, it appears that typical mtb tires running at
typical pressures produce a bit over twice as much rolling resistance
as typical road tires running at their typical pressures. Add to that
the fact that the more upright seating position of the mtb increases
aerodynamic drag, as does the larger frontal area of the mtb itself,
and I think it's probably safe to say that a typical knobby-tire mtb
requires a bit over twice the effort of a typical road bike at the
same speed.

--
Typoes are a feature, not a bug.
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recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a general
rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

Depends...

Compare a nice, light road bike with high-pressure 23mm tires to a
full suspension bike with knobbies, and it's probably more than 1.25x.

OTOH, throw a set of 1.25" slicks on a hard tail frame, mount a stem
that allows a reasonable reach out to the bars (for a fairly low
position), and the difference would probably be more like 1.05 to
1.1x.

Take that second MTB, mount 1.0" slicks and a rigid fork (or shock
fork with a lockout), and compare it to the road bike with the rider
sitting in what's essentially the same position on the brake hoods,
and there will be very, very little difference.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a general
rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

Check out:

http://w3.iac.net/~curta/bp/velocityMetric/velocity.html

You can do side-by-side comparisons with different tire types and
riding positions. Choose a power output based on guestimates and see
the difference.

Plugging in my personal power and weight values, I get pretty close to
your estimate of 100 == 125. That's MTB tires vs clinchers, drops vs
bar-tops.

Joseph

Here's a good real-world comparo:
I have a MTB with front Marzocchi shock, 1.5" Kenda Kwest slicks; and a flat
bar road bike with 25mm Conti Gatorskins, both set up with the same
freewheel gearing (11-34), although the chain rings are different gearing
and triple vs. double. I ride them dressed the same way with my Camelbak
full, etc. When I've rode the the same routes, the difference in average
speed is about 1 mph, with the road bike being faster. But I can keep up
with roadies on either bike.

So the difference is pretty minimal and if you do alot of bike path/lousy
streets/road riding, the MTB setup with slicks is probably the better way to
go -- that way you can take on whatever the road throws at you.

The biggest difference between the two setups is that it's a little easier
to ride a perfectly straight line on the road with the MTB due to extra
deflections from the suspension fork.

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an

MTB

Quoted message said:

Quoted message said:

should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km

road

Quoted message said:

Quoted message said:

loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a

general

Quoted message said:

Quoted message said:

rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

Check out:

http://w3.iac.net/~curta/bp/velocityMetric/velocity.html

You can do side-by-side comparisons with different tire types and
riding positions. Choose a power output based on guestimates and see
the difference.

Plugging in my personal power and weight values, I get pretty close to
your estimate of 100 == 125. That's MTB tires vs clinchers, drops vs
bar-tops.

Joseph

some physics person could help you

"recycled-one" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a
general rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

"Werehatrack" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a
general
rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

From some online sources, it appears that typical mtb tires running at
typical pressures produce a bit over twice as much rolling resistance
as typical road tires running at their typical pressures. Add to that
the fact that the more upright seating position of the mtb increases
aerodynamic drag, as does the larger frontal area of the mtb itself,
and I think it's probably safe to say that a typical knobby-tire mtb
requires a bit over twice the effort of a typical road bike at the
same speed.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

I would tend to agree just from the fact I have both and one weighs twice as
much. I use 100psi slicks on the MTB though which would cancel your
argument for me.

recycled-one said:

I ride an MTB for road rides. Obviously a kilometre of pedaling on an MTB
should count for more in effort/accomplishment compared to a tricked out
road racer.

So, what should be the conversion factor? Let's say you do a 100 km road
loop on an MTB. What should that be in road bike kilometres?

Ya, I know it depends on the specific bikes. I'm just thinking of a general
rule-of-thumb. My guesstimate is that 100km MTB == 125km RB

Based on some calories burned *estimators* I have seen, a MTB rider
burns in the area of 133% of the calories as on a road bike.

There are too many variables IMO. Type of tires (on both bikes),
position, weight, are you "MTB'ing" on or off road, if of, how techical
is the terrain, etc.etc.etc.

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