UKC

Is there an equivalent for road or MTB to Naismith's rule?

Not thinking of hard core audax or mad cx racing, just having a normal sort of day out riding and wondering if there was a rough guide to likely time.

In reply to Andy Hardy:

Very personal, and for me changes hugely with terrain. On my road bike when I lived in Finland I could easily keep at 28-29 kmph for long rides, 100 ´- 150 kms. Since moving to Sheffield it seems like I'm doing well to get much over 20 kmph on longer rides just due to the hills! But I don't think you can factor that in as neatly as with Naismiths.

In reply to Andy Hardy:

I seem to remember asking the same question a few years back, and the conclusion was - no

The big difference is that angle plays a much bigger factor in cycling (particularly road) - you gain almost as much as lose on easy gradients, but as it gets steeper you slow down both up as well as down

In reply to Andy Hardy:



I guess the only way to do it is measure your ride times and speeds in different terrain to give you averages, and then adjust according to profile of the route you are doing. Don't forget to factoring looking at the view and the odd puncture repair. The other thing that can make a world of difference offroad is the conditions. If it's raining will make a difference, but what really does it is what the conditions have been like in the weeks before. if the water table is up and its boggy, Naismith's is probably the best tool as you'll be barely doing walking pace, when on a day at the end of a dry spell you could be cruising at 20kph.

Bikehike.co.uk is an excellent tool for planning as it will give you a profile which really helps (and can export GPX files etc for a garmin/twatnav if you have one)

For a leisurely pace ride I generally I reckon on 10-15KPH off road in good conditions - this gives a bit of flexibility for stops and so on, 7-10 if it's likely to be muddy or boggy, If I'm out on a hard "training" ride rather than fun, then I'd be looking at the same speeds as averages but MPH instead

In reply to balmybaldwin:

Thanks everyone, when I have worked out the formula I'll patent it as Hardy's rule

In reply to Andy Hardy:

Not really. If you have a sharp bend at the bottom of a descent you lose all momentum and can crawl up the other side. Rolling hills you can often get up the other side whilst still moving at a fair rate. If the ascent is technical off road slower again, if smooth forest trail same gradient much faster. On the road shallow gradients below say 5% you can big ring it at a fair luck uphill, above that you'll start dropping gears and speed as your heart rate climbs...

In reply to Andy Hardy:

Really difficult, I'd suggest. I tend to work on averages modified to take account of distance, hilliness, wind and whether or not in a group. Other things such as traffic lights, right turns etc can really slow you down, so open roads will tend to be faster than a route that takes in towns. Big hills are a different game altogether - 5 hours churning away in the lowest two gears is unlikely to be recovered by reckless descending on the other side.

For what it's worth, I use the following, assuming a smallish group of mixed fitness who can sustain a 21mph average for an hour on a flatish course (with a few short sharp hills) and then stop for a well-earned pint - this as a general meausure of fitness.

Rolling terrain - 18 mph for 45 miles (c. 1,500 feet of ascent)
Hilly - 16 mph for 45 miles (c. 3,000 feet of ascent)
If there's a strong wind, then the rolling course pace may well come down to 16.5

For a group who can manage maybe 20mph for the hour blast - if they've got at least one or two strong members among their number:
16.5 for the rolling course, and maybe 14 for the hilly.

Planning figure for me - 17mph on my own, 15 in hilly terrain. Mountains - depends. Relatively slow on the way up, relatively quick on the way down. Average speed heading into London and back out again (20 miles each way, with 500 feet of ascent on the way back) - 16 in, 14 out. Ride London - closed roads and shared workload - 22mph for 100 miles.

Make of that what you will.

As a really rough guide, for a cyclist of reasonable fitness on a road bike, putting some effort in, riding 50 miles a week, try 15mph as an average. Expect less if it's hilly or windy

In reply to Andy Hardy:

If you know your functional threshold (critical) power there are some interesting tools on the net that will take a .gpx file and calculate an overall time as well as an effort profile. You need to dial in your preferred pace though, i.e. tempo or endurance.

https://whatsonzwift.com/gpx-to-zwift-workout/ (free)
https://www.bestbikesplit.com/

Or course conditions can have a very large effect.

In reply to Andy Hardy:

Anyone hazard a guess how many kcals are burnt cycling?

For a 35 mile, 3000ft of ascent in about 2.15 my very basic garmin reckons about 1500-2000

Is this remotely sensible?

In reply to Andy Hardy:

Shouldn't that be Naismith's rule for velocipedes?

Anyway I'm sure his rule would be : don't.

In reply to Tim Davies:

How much weight are you lifting?

In reply to Andy Hardy:

75kgs

In reply to Tim Davies:

If I assume you averaged at 200W on the flat, and then add on the work to vertically lift 85KG (75KG plus 10 to cover your bike & kit), then the energy required for this rough calc is:

200W= 200J/S
2 & 1/4 hr ride = 1800sec
Which means you need 1620000J in energy output (for the flat bit)

For the vertical lift = force*distance
850N*910M = 773500J

Total: 2393500J

Now because the body isn't that efficient in turning calories eaten into work done, we have to assume an efficiency... generally this is thought to be 22-26%, so lets use 24%

kCal (burned)=[(Total energy required (kJ)/4.2)/0.24)]

= 2374.5

(Which is prob an overestimate)

So it's about right if you take out the estimation errors I'll have made

In reply to balmybaldwin:

Thanks ! I always reckoned that even if it was 1000kcls it's still a few bars of choc or an extra cake (or small coffee at costa with extra marshmallows).