Blip, Zap, Splat

[boogerblaster]

Bikerpet, I used to race Hare Scrambles and you are correct. If you come upon a log say 3 feet in diameter going about 40 mph you do get a Much bigger lift. Believe me it's a very violent way to jump a bike , and will use all of 14" of travel and leave you wishing there were more.

[boogerblaster]

I forgot to say that the anti-squat reaction of the rear suspension is what keeps the rear tire pressure on the obstacle for traction. More throttle, more anti-squat, more traction.

[bikerpet]

10 hours ago, boogerblaster said:

Bikerpet, I don't double blip. After I get the front wheel up I leave the throttle on ( a little for small obstacles, more for larger ones ). It keeps the rear suspension from bottoming so hard , because it encourages an anti-squat reaction in the rear suspension. 

I'd suggest you work on altering that approach. Get off the throttle as the back wheel hits the obstacle.

You destroy traction when you drive up things on engine power, the slightest skid & the tyre quickly spins up and you stop. If you drive up on a trailing or closed throttle the tyre will never spin up. It might still lose traction, but it won't spin.

This is where riding on throttle alone is a dead end. You have to learn to ride on the clutch in order to be able to adjust power & acceleration quickly enough.

If you ride in to an obstacle slowly (as is common) then you simply can't build enough inertia to climb a larger obstacle power-off with throttle alone. But if you learn to build plenty of RPM & then control the power to the wheel with clutch then it's easy to have ample inertia in the flywheel to get you up big steps even with throttle closed.

Throttle = available power

Clutch = applied power

Oh, and chain tension squats the bike more, not anti-squat.

[bikerpet]

10 hours ago, boogerblaster said:

I forgot to say that the anti-squat reaction of the rear suspension is what keeps the rear tire pressure on the obstacle for traction. More throttle, more anti-squat, more traction.

Sorry, no gentle way to say it, but you are absolutely, totally wrong with this.

Watch & listen to some good riders tackling big obstacles. Its abundantly obvious that the throttle is closed or dramatically reduced during most of the climb. You'll hear big rpm as they set up, then as they launch the noise falls away dramatically. At the top there is often an increase in rpm again as they ensure they've got power on hand to fine tune the last bit of the climb. If you can watch & listen in slow motion you can hear individual ignitions of the engine and you'll really understand what happens.

Forget about about your squat/anti-squat ideas, that's going to take you nowhere in trials.

What keeps the tyre on the obstacle is the rider.

If you can find a good trials coach, spend some money and save yourself years. There's a lot of pretty ordinary coaches out there (plenty who can ride, but can't teach), so do your research. If there's no one near you, take a look at neilprice.com its far the best online coaching I know of.

[boogerblaster]

On 5/3/2023 at 6:16 PM, bikerpet said:

Sorry, no gentle way to say it, but you are absolutely, totally wrong with this.

Watch & listen to some good riders tackling big obstacles. Its abundantly obvious that the throttle is closed or dramatically reduced during most of the climb. You'll hear big rpm as they set up, then as they launch the noise falls away dramatically. At the top there is often an increase in rpm again as they ensure they've got power on hand to fine tune the last bit of the climb. If you can watch & listen in slow motion you can hear individual ignitions of the engine and you'll really understand what happens.

Forget about about your squat/anti-squat ideas, that's going to take you nowhere in trials.

What keeps the tyre on the obstacle is the rider.

If you can find a good trials coach, spend some money and save yourself years. There's a lot of pretty ordinary coaches out there (plenty who can ride, but can't teach), so do your research. If there's no one near you, take a look at neilprice.com its far the best online coaching I know of.

I didn't say to full throttle it . It's a combination of rear suspension design and rider technique. I'm an engineer and I always look at a situation from that point of view first , because if a bike is poorly designed NOBODY is going to be doing splats.

 

[boogerblaster]

On 5/3/2023 at 6:00 PM, bikerpet said:

I'd suggest you work on altering that approach. Get off the throttle as the back wheel hits the obstacle.

You destroy traction when you drive up things on engine power, the slightest skid & the tyre quickly spins up and you stop. If you drive up on a trailing or closed throttle the tyre will never spin up. It might still lose traction, but it won't spin.

This is where riding on throttle alone is a dead end. You have to learn to ride on the clutch in order to be able to adjust power & acceleration quickly enough.

If you ride in to an obstacle slowly (as is common) then you simply can't build enough inertia to climb a larger obstacle power-off with throttle alone. But if you learn to build plenty of RPM & then control the power to the wheel with clutch then it's easy to have ample inertia in the flywheel to get you up big steps even with throttle closed.

Throttle = available power

Clutch = applied power

Oh, and chain tension squats the bike more, not anti-squat.

Again I am not advocating heavy throttle. You're putting words in my mouth. Also my technique works fine. Been doing it for 50 years . I could do well in the expert class but choose to ride intermediate as I don't heal quickly or fully these days. After being paralyzed multiple times ( once quad, multiple times para ) my focus is live through the ride. And have fun.

[boogerblaster]

On 10/29/2020 at 6:51 AM, lineaway said:

 The real good riders do not need a kicker!

I agree.

[bikerpet]

10 hours ago, boogerblaster said:

I didn't say to full throttle it

Nod did I say you did. But you did say:

On 5/3/2023 at 10:44 PM, boogerblaster said:

More throttle, more anti-squat, more traction.

which does imply that full throttle is going to give Max. traction.

10 hours ago, boogerblaster said:

Also my technique works fine. Been doing it for 50 years

Great, carry on using it. But bikes & technique have moved on a bit over the past 50 years so possibly there's better ways to tackle some things.

I get it if you're happy with what you're doing & it works, you've obviously had a long time to refine it.

But just because you're an engineer & your technique works for you doesn't mean there may not be another potentially correct analysis.

In fact claiming "engineer" status does little to support your assertion - civil, software, electronic, structural; there's a lot of engineering disciplines with little or no relevance to suspension function. You may well have all the knowledge & experience to truly analyse this, but I've seen so many people say "I'm an engineer" only to discover their engineering is in a totally irrelevant field, or that they call themselves an engineer because they work in an engineering machine shop. Yes, I'm naturally sceptical.