Couldn't go any faster...

[tfkrocks]

Was riding on Vasco Rd. earlier (the hilly, windy part) and at one point I found that my bike was refusing to go any faster while going uphill. I was WOT at ~6k rpm going 65 mph and stuck there.

I'm not sure what to think of that as I was fine on the highway later. Any ideas what the cause of that might have been?

@rojoracing53 @CycleCam303 Figure you two would know what area I'm talking about.

[jkv45]

Originally Posted by tfkrocks

I was WOT at ~6k rpm going 65 mph and stuck there.

There's not much power at 6K, and it wasn't enough to accelerate the cycle up the hill.

In that case you have to downshift at least 1, and maybe 2 gears to get the engine up to where it makes its power - closer to 10K.

[fishdip]

Originally Posted by tfkrocks

Was riding on Vasco Rd. earlier (the hilly, windy part) and at one point I found that my bike was refusing to go any faster while going uphill. I was WOT at ~6k rpm going 65 mph and stuck there.

I'm not sure what to think of that as I was fine on the highway later. Any ideas what the cause of that might have been?

@rojoracing53 @CycleCam303 Figure you two would know what area I'm talking about.

You need to shift down.

[CycleCam303]

Yup, both Jason and I have been drafting each other wide open barely holding 70 mph. He's the expert but the uphill and strong wind just pummel the poor bike.

[CycleCam303]

The area she is talking about can be deceptively windy. Like super headwind. The as soon as you get away from the windy area the bike pulls from 6k no problem. It's just that its odd because I don't think people realize how much wind resistance and going up hill hurts acceleration.

[tfkrocks]

I was definitely at a higher speed and rpm before going up the hill. Didn't think the wind was actually that bad at that particular moment but I guess it was. I suppose there's a reason those windmills are there

[lgk]

Were you tucked?

[rojoracing53]

Wellcome to my world.

Don't worry it just a very sting strait on head wind right there so you don't feel it hitting you, all you feel is "why the **** is my bike losing all its power". I always start up at 70-75 and most days I need 5th gear to stay above 65, others I can stay in 6th, but sometime I have to go to 4th and I still end up doing 55. On those 4th gear days in the back of my mind I worry that something is wrong with the bike but then its ok after the climb.

Also keep in mind my bikes a fair bit faster then a stock and my 5th gear it taller then your sixth. I always walk away from Cam on that climb where he draft me or not.

[rojoracing53]

When I ride my bicycle to work from Brentwood to Livermore that **** headwind drops me to like 3-4mph and I have no choice but to stand up to pedal(very not arrow dynamic) because my gearing is to tall for anything below 6mph.

But on the other hand I can hit over 60 on the bicycle coming home

[lgk]

I cant even imagine going 60mph on a bicycle, it felt awesome enough going 40.

[tfkrocks]

Ok good I'm not crazy haha. And geez I would not want to ride a bicycle on those hills. Then again, I just don't care much for bicycles in general haha.

[jkv45]

Originally Posted by CycleCam303

The area she is talking about can be deceptively windy. Like super headwind. The as soon as you get away from the windy area the bike pulls from 6k no problem. It's just that its odd because I don't think people realize how much wind resistance and going up hill hurts acceleration.

All the more reason to downshift and get the engine into its powerband.

I wouldn't expect much acceleration at 6K. If you want acceleration in that situation you'll need to spin faster than that.

[tfkrocks]

I didn't need to accelerate. What got me was that I had been moving faster and I slowed down all of a sudden. It almost felt like when it's time to switch the petcock to reserve on a pregen.

[Motofool]

Originally Posted by tfkrocks

I didn't need to accelerate. What got me was that I had been moving faster and I slowed down all of a sudden. It almost felt like when it's time to switch the petcock to reserve on a pregen.

You don't have to read this, Rebecca; it is just the compulsive nerd that lives in me:

Our engines are strong only in certain narrow range of rpms': it is called peak performance.
Other types of engines, like the ones in Harleys', are strong in a more wide range of rpms': it is called flat performance.

The first type has many gear combinations in order to keep that rear wheel strong for any speed of the bike.
The second type of engines have less gear combinations, because the strength of torque of the rear wheel is there for a big range of speeds while keeping the same gear.

When we are rolling on a level road, the main force that opposes our forward movement is friction from the air that we are disturbing.
At open wide throttle, our bikes can only reach certain speed because they have a limited power (~30 HP in the narrow range of rpms' mentioned above).
That power is force times speed.
We reach a top speed because our rear wheel reaches a top force or torque.
If we don't keep the engine rotating in the narrow range that makes it stronger, we cannot reach that top speed, simply because we will have less torque at the rear wheel to push us forward.

Now, when you were climbing a hill, part of your weight became a force pulling your bike backwards.
A strong wind against your movement only adds to that force and the friction from static air.
In those conditions, the product force times speed tries to keep the balance; hence, the need for more compensating forward force induces a reduction of speed.
As the rear tire slows down, the engine regime is moving away from that optimal peak, becoming dramatically and quickly weaker and weaker in force or torque.

By opportune downshifting, you could try keeping the engine closer to the peak performance.
If you are late downshifting, the engine has no enough torque to increase its rpms' up to the optimal range (peak performance).
If the angle of the hill becomes big enough, the weight's component of the backwards force could be so strong that the bike couldn't climb even in first gear.

[gantt]

need more torque baby!!