Dual sus

[Wyatt Earp]

and for those who argue that you loose power etc have obviously never ridden a full suss...

 

With you here my man.

[Johan Bornman]

I'm gonna leave the debate there' date=' as a motor mech and also worked on and tuned suspensions for race cars I like to think I learnt a couple of things. I have a full suss bike, and for those who argue that you loose power etc have obviously never ridden a full suss...[/quote']

 

Hmmmm. 

 

We get this here quite often. Someone makes a statement, doesn't understand how it really works, then walks off in a huff with a parthian shot of how much experience he/she has in the particular field.

 

Two days ago we had a guy who "worked with metal all his life" and now this. But, the most amusing one was a guy who told me he actually is a rocket scientists and therefore I should believe him. He couldn't explain his claims either.

 

I have no doubt that you will now leave the "debate" but a discussion is not a debate when we don't have counter-arguments backed up with evidence - in this case simple physics.

 

I don't need to ride a full suspension to understand a couple of fundementals, just like everyone who rides a full suspension don't necessary understand forces. That little statement of yours is just an attempt to discredit me.

 

This is the Tech Q&A section and we try and stick to the facts.

 

 

 

 

 

[Wyatt Earp]

 

This is the Tech Q&A section and we try and stick to the facts.

 

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Well get with the program then.

[techguy]

Haha Dangle...

 

JB I don't know why you think I'm trying to discredit you, I never mentioned your name or quoted you...If read my opening statement I said I was opening a can of worms, as this topic has been discussed in length several times before, If I were to ask you your background what would your answer be? I am stating mine to give some sort of insight as to say I like to think I know what I'm talking about. I think your approach is a "BS baffles brains" trying to make things so complicated that not even you understand what you are saying.  NOW I'm discrediting you!

[X-Gear]

Get a Specialized with Brain shock.  Problem solved. 

[techguy]

Have one, I still run it with the brain all the way off...

[Mr. G]

Locking out my F/S on long and less rocky climbs, keeps the power pushing me forward and wastes none into the suspension!

[Johan Bornman]

Haha Dangle...

 

JB I don't know why you think I'm trying to discredit you' date=' I never mentioned your name or quoted you..

 

[/quote']

 

Sean, I'm the only one that disagreed with you and you fired a shot into the crowd saying we cannot understand how this work unless we ride dual suss. I think that is silly, considering we're talking about the physics of something here and experiencing it not a prerequisite for understanding. It is a simple line drawing of forces that's required.

 

I therefore consider that you addressed me. I think it is a fair assumption.

 

 

 

.If read my opening statement I said I was opening a can of worms' date=' as this topic has been discussed in length several times before,

 

[/quote']

 

We open lots of cans of worms here. No-one worries about that, we stick to the facts and the mechanics of it, no matter how controversial. That is not the issue. It is a red herring.

 

 

 

If I were to ask you your background what would your answer be? I am stating mine to give some sort of insight as to say I like to think I know what I'm talking about.

 

 

I would not answer you because I don't believe it has anything to do with the facts. My or your background has nothing to do with the argument. Only people who cannot substantiate a point will attempt to strengthen the argument with background' date=' education or tenure. I purely look at the argument.

 

 I think your approach is a "BS baffles brains" trying to make things so complicated that not even you understand what you are saying.  NOW I'm discrediting you!

 

 

I honestly dont' care what the aunties in Sandton think of me or my approach to things. People who know me here will probably give me some credit for at least explaining my statements. I understand what I'm saying and if my language baffles you, get a dictionary.

 

Now, back to the argument. We now know that you've tuned cars in your back yard, raced up and down in a souped-up vehicles of all types and have done so for years. We also know you've ridden motorbikes and hardtails and dual-suspension bikes.

 

Now get down to nuts and bolts and please substantiate your claims and explain why you say what you say.

 

 

[Fitter]

From JB:

I think the analogy is off kilter. Squatting under accelleration is completely different from bob during pedaling. Completely.

 

Squatting under accelleration on a motorbike or car causes no power loss. It was mildly irritating on BeeEms but did not affect its accelleration.

 

Bobbing whilst pedaling a bicycle produces lots of power loss. It messes with your rythm as well.

 

I fail to see how a bike is designed so that the rear wheel digs in under accelleration. Rear wheel downforce is a function of the rider's weight and to an extent, the shift in weight caused by accelleration. However, we don't accellerate fast enough to cause any weight shift to the back, so that is moot. We do brake fast enough to cause the reverse though.

 

A comparison of what happens when you brake hard and accellerate hard should make this clear to you.

 

Since you are making some unsubstantiated statements here, perhaps, nuts and bolts you know, you could substantiate your claims and explain why you say what you say?

 

 

 

 

 

cyclequip12010-05-26 05:52:01

[techguy]

Basically JB by your dodging my question about your background it proves to me that you are truly a 2nd hand cell phone sales man...

 

The truth is its the same as the 29er debate, it doesn't matter how many facts and physics you throw into the argument the average buyer of a bike will ask the question "is it better and will it work?" the simple answer is Yes.

 

Why do you think brands like Specialized, Trek to name two spend hundreds of thousands of dollars developing full suss designs and market them? Because they are better. And while they fit them with shocks that have a platform function it's because thats what the market dictates and if they didn't spec them with a Fox RP23 for example they wouldn't sell the same number, not because the system needs it. Thats a fact.

[BrendonMyb]

popcorn moment

 

kidding....

 

i know nothing about duelis so i cant help here

 

I have ridden my neighbours very beautiful spez epic but oh so above my budget bike. Have found it to drain me a little with the bobbing however the suspension was not set up for me.

 

have to admit though its very nice - wouldnt mind one for myself but on the other hand i have to admit that i love my HT too & will in all liklihood get myself another

 

sorry hijack over as im veering off point here

BumpNgrind2010-05-26 06:05:55

[TomvdP]

Ok, while I agree with JB that no suspension can increase downforce on the wheel there are certain types that can resist compression under pedal induced acceleration.

 

The diagram below shows Giant's Maestro suspension (and to a certain extent VPP - they are very similar)

Green - Force by shock (actually down on the rear triangle due to swing arm)

Blue - this is the important one, this is the force of the chain pulling the rear wheel forward, as well as the forward drive from the rear wheel.

Solid red is the swing arms

If the bottom swing arm was actually where the dotted red line is then all that forward force would be for nothing

BUT

By placing it at an angle when the forwards force is applied there is actually a downward force (on the rear triangle) from the lower swing arm which will prevent pedal bob.

So lockout is actually not necessary on this system - unless your pedalling style is inefficient to the point where it overcomes this force.

 

 

[Muddy]

 

Have one' date=' I still run it with the brain all the way off...[/quote']

 

Yip we can see that

 

[Mr. G]

What was the original question again???

[techguy]

What was the original question again???

 

When to lock out the suspension...

[Fitter]

The geometry of the Maestro is designed to resist chain jacking on the rear shock - but this is just one element of many factors affecting suspension kinetics.

I believe the thrust of JB's assertion had more to do with weight shift under acceleration (and correct me if I'm wrong here) and to this end the Maestro won't help a rider shifting weight under hard pedal efforts (like when standing). This will cause "bobbing" easily as much as chain jacking. I'd still like to hear JB's reasoning as to why squatting under acceleration differs between cars and bicycles. Also, some detail on the power robbing that bobbing apparently causes, and why pedal acceleration (I assume seated, to assist JB's assertion) causes so little weight shift as to rule it out of the equation.

cyclequip12010-05-26 07:44:27