Horst Link no longer relevant??

deanopatoni said:

Horst link a 'Dead Fish'?

The original philosophy behind the Horst link was to lessen the effect of braking induced jacking and chain torque suspension squatting. Back in the day bikes relied on rim brakes which due to their location being so far from the centre of the rear axel, meant that they would cause the suspension to jack up under breaking as the entire rear end was pivoting around the main pivot point (adjacent to the bottom bracket). The Horst link greatly lessened this effect by effectively disconnecting the seat stays from the equation.

The other reason for the Horst Link was that when tension was applied to the chain (ie peddling) the effect was to make the suspension squat as it tries to pull the rear axle toward the bottom bracket. Again the Horst link fixed this. Fast forward to 2005 when most full suspension mountain bikes have disc brakes the need for the horst link is irrelevant, because the braking force is applied a lot closer to the rear axel, result being no suspension jacking. What about the chain torque squatting you ask?

That was eliminated shortly after the Horst Link invention by lifting the main pivot point from adjacent to the Bottom bracket to more in line with the top of the granny ring.

In conclusion, my opinion is the day of the Horst link has gone, its no longer relevant, and good on Turner for having the balls to change their design.

PS The new design, in my opinion results in a frame design that will last longer that a horst link design, because previously the rear pivots were subjected to a greater amount of sideways pressure from the rear wheel. The TNT solution means that the rear wheel is connected to the bike by a single swing arm, and that's got to count for something.

I'm buying one..... (a TNT model that is).

Click to expand...

As for braking, the disc brake force is much closer to the axle than rim brakes but is the force is also proportionally larger. The brake force applied to the wheel and the force at the tire contact patch can be (for linkage calcualtion purposes) be replaced with a force and a torque at the rear axle that will be identical for disc brakes and rim brakes and it also doesn't matter what orientation the disc or rim brake is mounted (the mounting location will matter for structural strength considerations).

The main reasons why riders can't tell the difference between HL Turners and TNT turners:

1. The main swingarm pivot is in the same place and the center of curvature of the HL is in almost exactly the same place. This means that the peddaling characteristics that are determined by the axle path are the same.

2. The rest of the linkage points are the same, so the progresivness of the linkage (or leverage rate curve) is almost exactly the same. This means that the behaviour of the suspension to bumps and pedal induced movement (as it applies to the rate curve) will be the same.

3. Theoretical differences in the braking behavior which appear to be significant due to the difference in location of the HL's instant center and the TNT's main pivot are not as significant in most braking situations because due to the high center of gravity, the forward wieght shift from decelleration unweights the rear tire to the point where the differences in brake squat between the two designs are much less than the braking force coming from the front wheel.

4. The geometry, pivots, and structural stiffness of the 2 designs are identical except for the area at the rear axle.

In short a Turner is still a Turner with only small differences.

Ridge Rider said:

As for braking, the disc brake force is much closer to the axle than rim brakes but is the force is also proportionally larger. The brake force applied to the wheel and the force at the tire contact patch can be (for linkage calcualtion purposes) be replaced with a force and a torque at the rear axle that will be identical for disc brakes and rim brakes and it also doesn't matter what orientation the disc or rim brake is mounted (the mounting location will matter for structural strength considerations).

The main reasons why riders can't tell the difference between HL Turners and TNT turners:

1. The main swingarm pivot is in the same place and the center of curvature of the HL is in almost exactly the same place. This means that the peddaling characteristics that are determined by the axle path are the same.

2. The rest of the linkage points are the same, so the progresivness of the linkage (or leverage rate curve) is almost exactly the same. This means that the behaviour of the suspension to bumps and pedal induced movement (as it applies to the rate curve) will be the same.

3. Theoretical differences in the braking behavior which appear to be significant due to the difference in location of the HL's instant center and the TNT's main pivot are not as significant in most braking situations because due to the high center of gravity, the forward wieght shift from decelleration unweights the rear tire to the point where the differences in brake squat between the two designs are much less than the braking force coming from the front wheel.

4. The geometry, pivots, and structural stiffness of the 2 designs are identical except for the area at the rear axle.

In short a Turner is still a Turner with only small differences.

Click to expand...

Good summary.

If someone had asked me a year ago how much difference there would be between a chainstay and seatstay pivot version of an otherwise identical bike, I would have said maybe 5%. I still think that's about right.

It's hard to perceive directly that level of difference. It might even be hard to measure it scientifically, given that experiments often have a + or - 5% accuracy.

I read many years ago in a road biking article that there was about a 2% efficiency advantage from achieving the same gear ratio with cogs twice as large. On a mountain bike consider a 44/22 combo vs. a 32/16. Could you feel that difference while riding? An even bigger difference has been measured between a clean chain and a dirty one.

Consider that the human mind probably works on the principle of "I'll see it when I believe it". Give Davide a TNT rear end to try. He paid his money for a Turner.

Also consider that the guys who buy floating brake kits and put them on their bikes seem to see an obvious difference. That difference couldn't be much more than twice as great as the difference between the HL and TNT Turners. You'd think that half of an obvious difference would still be noticeable. Could it be that the guys buying the floater kits want to see a difference and the Turner riders don't?

Jaybo said:

I have heard from two bike insders that Turner changed designs due to Ellsworth! They would not go into it but said the change was due to economics and not functionality. I have to laugh now when I see Quality without Compromise. Well, there is one compromise: TNT.

Jaybo

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Very true! the main reason for the change was because of the ICT patent not the FSR/HL- it has all to do with paying his main competition money for the ICT patenet which is a bunch of bull, DT did not re-invent the wheel here, he simply moved the pivot to the seatstay like ventana has done for years - to think that he changed the design for any other reason is foolish - DT him self has said that the HL design was the best application for his bikes, he used the HL design for many years with no problem - then TE somehow gets a patent on some imaginary line & DT now has to pay that royalty - a year later DT gets away from the very design that he has mastered & come to be well known for hmmmm!
A year ago if anyone would have asked " I wonder what a turner would be like with a seatstay pivot" or "what is better faux bar or HL" that person would have gotten wrecked on this site -- now that turner is a faux bar, it is now the greatest thing ever like it is something new - its been around for a while just ignored until now -

change

ayce said:

Very true! the main reason for the change was because of the ICT patent not the FSR/HL- it has all to do with paying his main competition money for the ICT patenet which is a bunch of bull, DT did not re-invent the wheel here, he simply moved the pivot to the seatstay like ventana has done for years - to think that he changed the design for any other reason is foolish - DT him self has said that the HL design was the best application for his bikes, he used the HL design for many years with no problem - then TE somehow gets a patent on some imaginary line & DT now has to pay that royalty - a year later DT gets away from the very design that he has mastered & come to be well known for hmmmm!
A year ago if anyone would have asked " I wonder what a turner would be like with a seatstay pivot" or "what is better faux bar or HL" that person would have gotten wrecked on this site -- now that turner is a faux bar, it is now the greatest thing ever like it is something new - its been around for a while just ignored until now -

Click to expand...

i think dt & the homer crowd both had to be satisfied that the design change would work. of course not everyone is satisfied. every design is a compromise & there is no such thing as perfection.

one good thing to me in all of this is that it has shown us that perhaps there is no holy grail in suspesion design and there is more than one way to skin a cat. perhaps it has opened our minds a bit.

it has to be the ultimate insult for a designer like dt to invent something, have it copied and then have to pay royalities on his own design. what does that say about our culture?

for people to say flippant bs like "oh look, there is a compromise!" or something to that effect is also disrespectful. i am sure i will get flamed for saying that, but i think it is ok to disagree or speak out about what has happened, but to bring it to the level of name calling is lame in my book.

i think the quality without compromise is in the build, customer service, and the commitment to making exceptional bikes.

ICT is not HL

Ridge Rider said:

As for braking, the disc brake force is much closer to the axle than rim brakes but is the force is also proportionally larger. The brake force applied to the wheel and the force at the tire contact patch can be (for linkage calcualtion purposes) be replaced with a force and a torque at the rear axle that will be identical for disc brakes and rim brakes and it also doesn't matter what orientation the disc or rim brake is mounted (the mounting location will matter for structural strength considerations).

The main reasons why riders can't tell the difference between HL Turners and TNT turners:

1. The main swingarm pivot is in the same place and the center of curvature of the HL is in almost exactly the same place. This means that the peddaling characteristics that are determined by the axle path are the same.

2. The rest of the linkage points are the same, so the progresivness of the linkage (or leverage rate curve) is almost exactly the same. This means that the behaviour of the suspension to bumps and pedal induced movement (as it applies to the rate curve) will be the same.

3. Theoretical differences in the braking behavior which appear to be significant due to the difference in location of the HL's instant center and the TNT's main pivot are not as significant in most braking situations because due to the high center of gravity, the forward wieght shift from decelleration unweights the rear tire to the point where the differences in brake squat between the two designs are much less than the braking force coming from the front wheel.

4. The geometry, pivots, and structural stiffness of the 2 designs are identical except for the area at the rear axle.

In short a Turner is still a Turner with only small differences.

Click to expand...

Good summery of the minimal pedaling and braking differences of ICT and monopivot TNT, Ridge Rider. And many great comments here by others.

The pedaling anti-squat and kickback are the vertually same in theory and ride tests now finally verify. The lower flex of the TNT design produces even more efficent pedaling responce. The braking tradeoff of the TNT's less flexy rear wheel mount and elimination of brake dive reaction offset the freer extending but more front suspension loading Turner 4-bar (so-called ICT) design.

The TNT design is a forward advance in Turner design, technically superior in all conditions than ICT.

I've said this for years. Turner invented his own designs. ICT is a written description of what Turner designed in the late '90s, which was followed by FSR design soon after Turner. The ICT patent even boldly sites prior design use by Turner, admitting it is a stolen design, without putting Tuner's name on the ownership application!

To the original post. So-called "ICT" geometry is not Horst link geometry.

HL has subtle but noticeable performance differences. Slightly more acceleration efficient, at the tradeoff cost of slightly increased pedal kickback than the ICT pedal kickback. And HL is slightly more bump compliant while braking at lower speeds than ICT, particularly more compliant than the more parallel versions of ICT which have significant rear suspension extending reactivity.

Unlike HL geometry, ICT does not change the axle path and subsequent pedaling reactivity compared to a monopivot with the same near BB pivot. The lower chain-stay pivot location of the HL produces a path that can be described by a monopivot if the pivot was where the back tire and front derailieur are, which has been impractical for bike design. Note that FSR design followed Turner in raising the chainstay pivots about inch higher above the HL geometry, but moved the BB pivot rearward as far as practical to somewhat maintain the Horst Link reactivity, but it compromised the more significant difference a Host link geometry produces.

An inch difference in pivot geometry is very significant when only a few millimeters in link geometry difference can sometimes make a noticeable difference.

Braking is potentially very similar between ICT and HL. The late '90's Turner "so-called ICT" geometry had HL type braking geometry. While the IC migrates in travel behind the front axle near axle height it is close to HL reactivity. For lower speed common trail riding velocity the HL geometry has more significant bump sensitivity compliance reactivity than when the IC is ahead of the front axle producing a rear suspension extending reaction. The HL become more compressive in mechanical reaction when deeper in travel and less compressing when in shallow travel, complementing bump travel traction compliance.

The more parallel floating brake designs more common of the Dare and latest almost yearly design change of the TE trail bikes are extending in brake reaction, effectively launching the rider if not for platform or slow rebound damping. Some downhill riders find advantage with extending brake reactivity, although the experts are not using floating brakes now days as much as in the nineties. The more rearward path DH designs such as high monopivot and Lawwill noticeably benefit from more extending reaction braking. Extending brake reactivity has no net benefit for slower trail riding.

Horst link has a noticeable pedaling and braking performance difference that many experts prefer. Many other experts prefer the soft pedaling and more stable braking lower monopivot design. It's a matter of personal preference.

- ray