Car vs motorcycle vs downhill bicycle

[tuxumino]

depends on the road and the cyclist, there are some bicyclists that would leave all but the best motard riders far behind on the decent from inspiration point to San Pablo dam road.
On that section of Wildcat Canyon road I think if you took the equivalently skilled bicyclist, rider and driver but they had never rode or drove that road, all three would go off the road.

 

[Carlo_Guzzi]

I hit 62 on the Carson descent, but I have much more ballast than most bicyclists who do that ride.

Me too, I think that ballast and a more aerodynamic shape (round with a bit of pear shape) are a plus in my downhill quest. Dang, you did get over 60! I really wanted that.

OK here's the math, stolen from another website:

You can easily determine your own speed using the following formula:

((((((T1/T2)D)3.1416)C)60)/12)/5280 = miles per hour

Where:
T1=number of teeth on the chainring (attached to the pedals)
T2=number of teeth on the cluster ring (attached to the rear wheel)
D=diameter in inches of the rear wheel (usually imprinted on the tire)
3.1416 = pi
C=your cadence - the number of revolutions per minute of the pedals
60=multiplier to change minutes to hours
12=divisor to change inches to feet
5280=divisor to change feet to miles
[/qoute]
So with my 54 front (52 is considered standard) and 11 rear (12 or 13 is standard) pedaling at 120 rpm with a 27" outside diameter tire (I just measured mine to be sure) I would be going 47.3 mph. I can pedal faster than that but form and available power go all to hell. I might have pedaled my way to 50, but certainly not beyond that. And the pros aren't either. Not because I'm as good as them, but because the equipment doesn't really allow it.

 

[ElectricPrunes]

There are some roads you can't drop a cyclist on. There's some roads I deliberately prevent cars from passing me on because I know the twisties are coming up and I'm gonna be riding their asses/looking to pass if I don't go first. Wildcat, mt diablo, mt halliekela on Maui, grizzly peak towards fish ranch/Claremont... South Park will get you up to 56+

 

[Brown81]

depends on the road and the cyclist, there are some bicyclists that would leave all but the best motard riders far behind on the decent from inspiration point to San Pablo dam road.
On that section of Wildcat Canyon road I think if you took the equivalently skilled bicyclist, rider and driver but they had never rode or drove that road, all three would go off the road.

My buddy Steve averages 37-39 mph on that descent.

But he is a fucking baller.

Likely blow the doors off most newb riders/drivers.

 

[kiltwearinfool]

My opinion? Depends on the road. When I was younger, I got all hopped up on adrenaline and testosterone & raced some buddies East down Woodside rd on a bike. I knew the road well & knew my capabilities. I passed a few cars, but my riding buddies called me insane & an asshole for being a "dick cyclist". Now, going West down the same road I would get left behind because the corners aren't as tight.

 

[ElectricPrunes]

My buddy Steve averages 37-39 mph on that descent.

But he is a fucking baller.

Likely blow the doors off most newb riders/drivers.

This is what the best cyclists are doing on that segment. Not quite 37 mph avg, but still ten over the speed limit on a road with some nasty hairpins, blind decreasing radii, and cars are barely doing 20.

http://app.strava.com/segments/406615

 

[Archimedes]

All depends on the sprockets. Thought everyone on BARF knew that by now.

 

[Brown81]

This is what the best cyclists are doing on that segment. Not quite 37 mph avg, but still ten over the speed limit on a road with some nasty hairpins, blind decreasing radii, and cars are barely doing 20.

http://app.strava.com/segments/406615

That's him at #11.

Coulda swore he showed me one over 37?

At any rate, a pretty good clip.

 

[redtail]

I think cyclist think they're faster downhill than everybody.

Back when I had my 2005 Buell, I was coming down Mt Diablo and caught up with two cyclist. They saw me and put their head down, which as you'd expect, didn't cause much acceleration on their part. So I get up behind them in the corner, in my opinion a motorcycle can go much deeper into a corner and carry much more corner speed than a bicycle, consider the contact patch, the tire compound, profile and tire pressures. They both were surprised to see me and one put his hand down in a back off motion. I'm thinking, wtf? It was okay as long as you thought you could out run me? I passed on the straight and never saw them again.

But to be fair, they are faster than the cars and squids.

 

[mean dad]

You can easily determine your own speed using the following formula:

((((((T1/T2)D)3.1416)C)60)/12)/5280 = miles per hour

Where:
T1=number of teeth on the chainring (attached to the pedals)
T2=number of teeth on the cluster ring (attached to the rear wheel)
D=diameter in inches of the rear wheel (usually imprinted on the tire)
3.1416 = pi
C=your cadence - the number of revolutions per minute of the pedals
60=multiplier to change minutes to hours
12=divisor to change inches to feet
5280=divisor to change feet to miles

Easily???

 

[russ69]

...He believes a downhill road bicycle will beat any car or motorcycle downhill...

No. Here's the list from fastest to slowest:

1. F1 car.
2. A whole bunch of formula racing cars (Indy light, Formula 2, ALMS, etc.)
3. MotoGP bike.
4. 250 go-kart.
5. Bicycle.
6. Skateboard.

Cars are the fastest things there are on a paved circuit and they are faster by a significant margin. Tilting the road downhill doesn't change anything.

 

[ElectricPrunes]

That's him at #11.

Coulda swore he showed me one over 37?

At any rate, a pretty good clip.

Yeah, he's hitting 37-40 mph on the straights, which is respectable without a car or bike to draft. I'm way down the list and have only done 35 on those parts.. I wanted to show off this website to folks who want to compare their motorcycle riding to cyclists. This is the way to do it.


While we're yapping about stupid top bicycle speeds, hwy 24 from fish ranch to orinda is legal for cyclists, is downhill and has a pretty massive slipstream with all the cars. I've been pulled over by CHP before on a bicycle. Lol. My top speed was 68 mph.

 

[protokultur]

<- also in the 60+ club, but I didn't know it until I downloaded the ride from the Garmin. That being said, descents of 35-45 mph are routinely possible on the long hills.

They both were surprised to see me and one put his hand down in a back off motion. I'm thinking, wtf?

So how about you back off then? It's a public road and he probably wants to descend safely at the speed limit without worrying about you making an unsafe pass. Just like if you were on the highway and an 18 wheeler is riding your ass.

To the OP's point, TdF is paced by motorbikes - so even in the case of cat 1 descents, a moto, with a good pilot, can keep up pretty well.

 

[reidconti]

I've hit 55mph on my road bike coming down monitor, but the moto has more grip and can accelerate between corners and then brake harder for the next one.

 

[Cycle61]

Tilting the road downhill doesn't change anything.

Sure it does. Fat guys on bicycles are faster than skinny guys on bicycles...downhill.

 

[redtail]

It's a public road and he probably wants to descend safely at the speed limit without worrying about you making an unsafe pass.

Really? Just curious, what did I say that made you come to that conclusion?

 

[mean dad]

So how about you back off then? It's a public road and he probably wants to descend safely at the speed limit without worrying about you making an unsafe pass. Just like if you were on the highway and an 18 wheeler is riding your ass.

How about if the bicyclist lets him pass? It's a public road, and the motorcyclist shouldn't have to wait for someone that can't maintain the speed limit.

But please, tell me how the moto rider didn't know how fast the cyclists would be, right after you tell him that the cyclist THOUGHT they would try to make an unsafe pass.

Also, in your 18-wheeler scenario, the moto rider should let the truck pass. Fucking duh.

 

[JPK]

Depends on the rider and the road and whether there are straight sections that would require pedaling or all curves. I'm definitely not a balls-out road bicycle rider (something about a wife and kids at home) but I can pass pretty much any car and about 1/2 of the motorcycles coming down the top part of the front side of Hwy 9. There are many bicyclists that are nuttier than me that could probably keep up with any moto. Where 9 becomes a little straighter and I have to pedal I'll get passed by pretty much anything motorized. The problem is that, to go that fast on a bicycle downhill, you need to be using the WHOLE lane.

 

[Brown81]

Yeah, he's hitting 37-40 mph at points. I wanted to show off this website to folks who want to compare their motorcycle riding to cyclists. This is the way to do it.

It's an interesting site, and exactly what he showed me. Thought it was pretty cool.

I'd bet they get well over 45 on that one fairly straight part.

 

[Brown81]

No. Here's the list from fastest to slowest:

1. F1 car.
2. A whole bunch of formula racing cars (Indy light, Formula 2, ALMS, etc.)
3. MotoGP bike.
4. 250 go-kart.
5. Bicycle.
6. Skateboard.

Cars are the fastest things there are on a paved circuit and they are faster by a significant margin. Tilting the road downhill doesn't change anything.

F1 car couldn't even get going down that road.

I'd bet money a 250 Kart would blow everything away down that hill.

Might lose the money but F1 cars make a lot of time up from 100-200mph, and I don't think that would be much of a benefit on that particular road. Like, the F1 might just be too much. Could be wrong. F1's are incredible machines!

But a 250 Kart on that downhill would be insane.