The effect of hills on average speed?

[huggy]

Can you calculate the effect of hills on average speed.

When walking you can use Naismiths rule, to give you a target or estimation how long it will take.

So this evening I did this average 13mph over 18 miles with 1100 ft of up and down (it was a loop).
http://ridewithgps.com/trips/1339967

Can we esimate what my average would be on a flatter course, not many flat roads to actually do it round here.

 

[Nebulous]

Hi - I've no idea if there is a rule, but I have several loops I use depending on time available / tiredness etc. I've built up a fair bit of data on what speed / time I can do them in and there is quite a bit of variability, which is more wind dependent than anything else.

Over 30-50 miles my flattest routes have about 35 feet of climb per mile. The highest I usually get is high 50s which is just under where you are at (61 feet of climb per mile) and that knocks between 1 and 1.5 mph off my average.

 

[redcard]

About the same?

 

[GrasB]

Can you calculate the effect of hills on average speed.

When walking you can use Naismiths rule, to give you a target or estimation how long it will take.

So this evening I did this average 13mph over 18 miles with 1100 ft of up and down (it was a loop).
http://ridewithgps.com/trips/1339967

Can we esimate what my average would be on a flatter course, not many flat roads to actually do it round here.

To get an idea of your ride time on a hill climb you need to do is get a good idea of your nominal altitude gain (VAM) an hour, your flat road still air cruising speed (V), then also know your total distance (D) & total elevation gain on the ride (EG).
D / V + EG / VAM
For arguments sake say you have 500m/h VAM & 25km/h V. You're doing a 40km ride with 200m climbing
D / V = 40/25 = 1.6h
EG / VAM = 200/500 = 0.4h
1.6 + 0.4 = 2h
So 20km/h (or 12.5mph).

This will always over estimate your time if you're doing a ride that include down hill sections as it is extremely hard to estimate your down hill speed. Put it this way, descend like a demon & be sprinting out of the corners to get up to Vmax ASAP on the descent (5% will get you to 25mph fairly easily on the hoods a road bike) will have a huge impact on your average speed rather than gently feathering the brakes keeping the speeds under 25mph.

 

[uclown2002]

How many climbing feet per mile would be considered flat, hilly etc?

http://app.strava.com/activities/55473630

107 feet per mile; seems rather common where I live. My 23 mile commute still has 85 climbing feet per mile and that feels relatively flat compared to most of my rides.

 

[GrasB]

my guide is on a longish circular route:
Flat = 0-5m/km
Rolling = 5-10m/km
mildly hilly = 10-15m/km
hilly = 15-20m/km
very hilly = 20-30m/km
insane >30m/km

 

[Nigelnaturist]

How many climbing feet per mile would be considered flat, hilly etc?

http://app.strava.com/activities/55473630

107 feet per mile; seems rather common where I live. My 23 mile commute still has 85 climbing feet per mile and that feels relatively flat compared to most of my rides.

Is that over the course of the ride. I just can't get anywhere near that normally including rides like this.

 

[Globalti]

my guide is on a longish circular route:
Flat = 0-5m/km
Rolling = 5-10m/km
mildly hilly = 10-15m/km
hilly = 15-20m/km
very hilly = 20-25m/km
insane >25m/km

Wow! Up here in Lancashire 25 metres of climb in 1 km is mild! A relatively gentle climb that most cyclists have to do is Bailey Bank, from the river Hodder to a place called Walker Fold just north of Longridge Fell; it climbs 109m in 3 km, so just over 36 m per km. Further along the same road you've got Jeffrey Hill, which climbs 135m in 1.35 km, so 100 m per km and is my more direct route home if I'm feeling strong enough late in a long ride.

 

[uclown2002]

Is that over the course of the ride. I just can't get anywhere near that normally including rides like this.

Yes, that particular route I linked to was 46.5 miles with an elevation gain of 4974 feet; so if my sums are right that is 107 feet per mile. Three Cat 4 climbs in there, but hard to avoid the hills near home.

 

[HLaB]

my guide is on a longish circular route:
Flat = 0-5m/km
Rolling = 5-10m/km
mildly hilly = 10-15m/km
hilly = 15-20m/km
very hilly = 20-25m/km
insane >25m/km

I'm surprised my commute this morning actually scrape into the 'Rolling' territory I,ve have to go out and seek hills bumps on the steel fixie.

 

[jowwy]

my guide is on a longish circular route:
Flat = 0-5m/km
Rolling = 5-10m/km
mildly hilly = 10-15m/km
hilly = 15-20m/km
very hilly = 20-25m/km
insane >25m/km

my commute home is 100ft/mile - so whats that on your rough guide??

 

[Nigelnaturist]

my commute home is 100ft/mile - so whats that on your rough guide??

about 19m/Km

 

[Rob3rt]

my commute home is 100ft/mile - so whats that on your rough guide??

Convert ft to meter and mile to km, do the division, then look at his post?

 

[GrasB]

my guide is on a longish circular route:
Flat = 0-5m/km
Rolling = 5-10m/km
mildly hilly = 10-15m/km
hilly = 15-20m/km
very hilly = 20-30m/km
insane >30m/km

Wow! Up here in Lancashire 25 metres of climb in 1 km is mild! A relatively gentle climb that most cyclists have to do is Bailey Bank, from the river Hodder to a place called Walker Fold just north of Longridge Fell; it climbs 109m in 3 km, so just over 36 m per km. Further along the same road you've got Jeffrey Hill, which climbs 135m in 1.35 km, so 100 m per km and is my more direct route home if I'm feeling strong enough late in a long ride.

Go back & think about this again after re-reading my post, paying attention to the bold bit.
Hint: in the 2010 TdF out & back of the 25 categorised climbs would give you 8 which did not make it to >30m/km. One of those was an HC category climb.

 

[jowwy]

about 19m/Km

so its hilly then lol

which makes the sportive i did onthe weekend hilly too......and very nearly in the very hilly category, no wonder i was tired at the end