[zedro]

Wow, splitting hairs much? You said "might want to wait..." That's not a suggestion?

Can't you ever pull back on something you said? Or maybe you really believe that nobody should try to run with an idea that nobody else has developed?

man, you just dont get what i'm saying....

 

[AlberTop]

might want to wait until it hits the automotive market first....

The best F1 car ever built, Williams 1993, had a full active suspension. It was so advanced that FIA banned the car and active suspensions.

Our bikes are like F1 cars compared to standard bikes. Why don't ask for some type of active suspension? At least until UCI forbids that.

 

[Jm_]

Wow, 3 pages...

Anyhow anyone that is knowledgable in car racing knows that you can stop quicker without ABS.

 

[zedro]

The best F1 car ever built, Williams 1993, had a full active suspension. It was so advanced that FIA banned the car and active suspensions.

Our bikes are like F1 cars compared to standard bikes. Why don't ask for some type of active suspension? At least until UCI forbids that.

that suspension was controlled by hydrolic rams, a smattering of sensors and two supercomputers. I'm not sure who you are gonna ask for it.

 

[Macrider]

that suspension was controlled by hydrolic rams, a smattering of sensors and two supercomputers. I'm not sure who you are gonna ask for it.

is the Bose suspension fully active?

I read their site about it, look very cool - Lord knows my Soundock is great ;-)

 

[zedro]

is the Bose suspension fully active?

I read their site about it, look very cool - Lord knows my Soundock is great ;-)

fundamentally i dont think so but it could be made to be since it doesnt use springs/damper units. And heres little article clip on the differences between re-active, semi-active and fully active suspensions:

"The system is able to change the attitude and ride height of the car according to certain control laws." The benefit is that at any given moment an active suspension system can optimize the suspension. To do this an active system can control three major areas: 1) The system can control ride height according to changes in weight and in aerodynamic loading. The system can react to internal loading, such as roll and be made to create roll or no roll. 2) The system can stop the car from pitching under braking or acceleration. 3) You can actually control the springing/damping and the hub motions of the car.

So called Re-active systems can perform only the first function. A Semi-active system performs the first and second functions, but only a fully active system actually achieves all three. Controlling the springing, damping and hub motion is obviously requires the most sophistication and is the most difficult to achieve. If it does not work there is no suspension at all! Wright, " With a semi-active system, if the computer says: 'I will do nothing at all,' you still have suspension." Wright continues by saying, "Those are great differences. There ar others, but these are really in the control laws - what you are asking the system to do. That is an area where it is impossible to know what other people are doing. You can only look at videos and guess."

What Wright is saying is that with a semi-active system there is a conventional passive suspension, springs and dampers. Whereas a fully active suspension, the system is capable of sensing bumps and nearly instanteously reacts. It does this so quickly that it's almost as if the suspension anticipates the bump. Compare this to a conventional spring/shock system and you'll find the conventional system extremely retarded, reacting with seeming casualness.

now unless your suspension would come with a couple of engineers and high powered laptops, i'm guessing you wouldnt even want fully active suspension. Well that and you need some kind of power supply for the ram mechanisms....

 

[S.G.D]

that suspension was controlled by hydrolic rams, a smattering of sensors and two supercomputers. I'm not sure who you are gonna ask for it.

check out prodrive active suspension!

mega cool!!

~SGD

 

[zedro]

check out prodrive active suspension!

mega cool!!

~SGD

its actually semi-active (or reactive):

"Prodrive Active Shock Technology (AST) is designed to help eliminate the compromise between handling and comfort, enhancing high performance without sacrificing ride quality. AST uses a semi-active shock absorber in combination with its proprietary Ride State Aware(TM) algorithm to ensure optimal control of body and wheel motions, thereby increasing comfort, control and grip. "

 

[AlberTop]

that suspension was controlled by hydrolic rams, a smattering of sensors and two supercomputers. I'm not sure who you are gonna ask for it.

I want that on my 2010 Boxxer.

Gonna email RS right now!

 

[Jm_]

I want that on my 2010 Boxxer.

Gonna email RS right now!

Your 2010 boxxer will only have hydracoil 4 and will still leak.

 

[zedro]

Your 2010 boxxer will only have hydracoil 4 and will still leak.

but it will be an active-leak system

 

[shock]

One of the main problems with "true" active suspension is that an accurate map of the exact course must be programmed into the computer. This is so the suspension can "anticipate" every variation, and adjust the suspension to compensate.

Even on an "easy circuit like Indianapolis (500 track, not F-1), the difficulty of accurately mapping, and the driver consistently repeating lines, is, at the moment, impossible, even with the highest sampling data acquisition available. Attempts to do so have dated back at least 20 years that I'm aware of.

Most other so called active systems are designed to correct/control a particular set of circumstances, like ride height and pitch (like brake dive and acceleration squat), or roll, and mainly for aerodynamic reasons.

I don't really see computer controlled active suspension as being a worthwhile goal for DH bikes, but manipulation of the mechanical forces that exist, and better schemes to react to them.

As for ABS brakes, they can offer some advantadges in car racing, such as eliminate the tendency to lock the inside front wheel (as it unloads) while braking into a corner. This not only helps reduce braking distance, but saves the tires.

Aside from the fact that it is illegal in most forms of auto racing, there is an inherrant distrust among drivers, who fear (rightly so) that abs might prevent them from intentionally affect the cars behaviour while braking. For example "backing it in" to a corner with the brakes, can be an effective way to get a reluctant car (or bike) to turn, and drivers don't want to give that kind of control up to a computer.

I think the same thing applies to bikes, if you're riding at a reasonably high level, the brakes are another control mechanism

 

[JoeRay]

Funny fact about ABS and cars.

ABS equipped cars may stop a little bit faster on sealed surfaces but the primary benefit is being able to steer round stuff, not a marked reduction in braking distances.

But all this changes when you get on unsealed surfaces, gravel and the like. On gravel an ABS equipped car will take longer to stop then a non-ABS car. Why?

Well on gravel becasue the surface is loose it builds up in a litle drift infront of the locked wheel. This increases the braking effect, more friction and all. But with an ABS car the wheel keeps rolling and doesn't get the little pile of gravel infront, so all braking is through the brakes not the brakes and road surface combined.

True, you'll be able to steer a bit still but the braking distance difference is substantial like 60 plus feet from 40 mph or so.

Back to our DH bikes and where to we usually ride these the most

 

[MMike]

it would be flexy

 

[Jm_]

Funny fact about ABS and cars.

ABS equipped cars may stop a little bit faster on sealed surfaces but the primary benefit is being able to steer round stuff, not a marked reduction in braking distances.

But all this changes when you get on unsealed surfaces, gravel and the like. On gravel an ABS equipped car will take longer to stop then a non-ABS car. Why?

Well on gravel becasue the surface is loose it builds up in a litle drift infront of the locked wheel. This increases the braking effect, more friction and all. But with an ABS car the wheel keeps rolling and doesn't get the little pile of gravel infront, so all braking is through the brakes not the brakes and road surface combined.

True, you'll be able to steer a bit still but the braking distance difference is substantial like 60 plus feet from 40 mph or so.

Back to our DH bikes and where to we usually ride these the most

Well, not really. ABS takes the brake to the point right before it locks up, and then it pulses on and off, sometimes it passes that point and it momentarily locks and lets go. In either situation, your stopping distance is more than if you could manually take it to the point right before lockup, and hold it there. Not everyone is an expert driver though, and this point changes widely based on the surface you are on (ice, snow, gravel, pavement, etc). ABS takes that part out of the equation and does a decent job of stopping you without locking up, it also gives you more control as a locked up wheel gives you absolutely no control. So auto-racers can usually stop a car with big disc brakes more effectively without ABS, as a general rule. There might be more advanced ABS systems out there now or that will eventually get good enough (if they don't already exist) to make any difference immesurable, but since there aren't many times where we are locking up our brakes (at least from my experience) on DH bikes, I don't see how ABS would do anything usefull, but increase our stopping distances.

If you are trying to steer while braking that hard, you are going to break traction and there's nothing that ABS can do to help. ABS is meant to give you a measure of control, but swerving radically while braking will still break traction.

 

[ioscope]

They exist, shimano made anti-lock v-brakes for commuters in the late nineties.

 

[BigMike]

This thread has become very interesting. A lot of good thoughts in here. Most of you know way more than I do about this stuff, so its interesting to read, Thanks

 

[MikeD]

They do have those stupid squishy noodles that they put on the front v-brakes on hybrids to prevent people from tossing themselves over the bars.

Back in the days of cantilever rim brakes someone came up with a pad that would make it very hard to lock up a wheel. Instead of static pads two rubber rollers were place with the axis of rotation just slightly offset from the rim tangent. The idea was that at high speed they would act like regular brake pads but when the wheel slowed down the rollers would start to roll preventing lock up. Needless to say they never really worked.

Shimano developed those way back, like 95/96. They were actually rim brakes, with 2 rollers for friction placed at angles. They didn't work so well.

just get a set of Vbrakes off a low end hybird. they come with this damper on the "noodle" that doesn't allow the brakes to lock up. tektro baby.

They exist, shimano made anti-lock v-brakes for commuters in the late nineties.

Hey, didn't someone make some sort of anti-lock rollers in the 90s? Or was it just a squishy brake noodle?

 

[BRacing]

Funny fact about ABS and cars.

ABS equipped cars may stop a little bit faster on sealed surfaces but the primary benefit is being able to steer round stuff, not a marked reduction in braking distances.

But all this changes when you get on unsealed surfaces, gravel and the like. On gravel an ABS equipped car will take longer to stop then a non-ABS car. Why?

Well on gravel becasue the surface is loose it builds up in a litle drift infront of the locked wheel. This increases the braking effect, more friction and all. But with an ABS car the wheel keeps rolling and doesn't get the little pile of gravel infront, so all braking is through the brakes not the brakes and road surface combined.

True, you'll be able to steer a bit still but the braking distance difference is substantial like 60 plus feet from 40 mph or so.

Back to our DH bikes and where to we usually ride these the most

Close. Cars that are designed for racing (especially off road/rally) still prefer ABS. The ABS computer is designed to allow for more 'lock up' to help build that "little drift in front of the wheel" before it pulses to regain traction. It's actually kinda funny, because it's as simple as changing a computer setting for different performance. You could even have an knob for adjustable settings on the brakes if you'd like.

Also, ABS does stop faster in most examples. But the main advantage of ABS is braking WHILE CORNERING. You can slow down later, after you've began your turn ("trail braking").

The technology is out there to make it applicable for Mtn Bikes. It could be installed with the front brake, the motor to pulse the brake fluid would be attached to the caliper. The sensors in the caliper/rotor. The computer/ power source/ adjustments can be mounted on/near handlebars. The hardest spot would be to find the "sweet spot" where you would want some slip, and when you would want the ABS to kick in.

Remember, we're not reduceing the braking POWER, we're decreasing the lock up of the wheel. You'll still be able to be flung over the bars using a properly set up front ABS.

-B

 

[Westy]

Hey, didn't someone make some sort of anti-lock rollers in the 90s? Or was it just a squishy brake noodle?

Actually it was a roller designed by Shimano but during lunch and engineer dropped an egg noodle on the prototype and the production guys didn't know any better and made them all that way. Rumour is the next generation geared hub will have sushi rice in it.

 

[MikeD]

Actually it was a roller designed by Shimano but during lunch and engineer dropped an egg noodle on the prototype and the production guys didn't know any better and made them all that way. Rumour is the next generation geared hub will have sushi rice in it.

It's too bad Shimano's not a German company. Bratwurst would be a good source of lubrication for a geared hub...one link could last years...