Whitey
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Hey all,
I’ve been struggling recently to get a decent amount of caster on my 120 with the OEM upper arms at a 790mm ride height. After recently finding my lower arm cams seized I replaced my lower arm bushes and after putting everything back together I was already rotating the rear PS cam almost right out to get just 1.5deg of caster. The front end handling was the worst I’ve ever had on my Prado, and I was pretty miffed with the wheel alignment after all the trouble of replacing seized up cam tubes.
As such, I started looking very closely at after market upper arms and what they could do, firstly in terms of caster (to improve high speed handling), and secondly in terms of what open length they bind up the double wishbone. Upper arm-Coil clearance at full droop is also a major criteria.
I’d already looked at upper arms previously just out of curiosity, and many of you will already be aware of the debate about uniballs vs ball joints.
My review of non-adjustable fixed caster uniball arms suggests that in lifted geometry they never give the amount of fixed caster claimed by the manufacturer. Uniballs suffer quickly from exposure to the elements and can end up losing material on the surface of the balls and rattle and squeak their way through a short service life. As usual, much of this information is from online forums, so these are reports of failures, and they always give a subjective opinion. A perhaps more rigorous assessment of uniballs comes from the desert racing community in the USA, where they are very popular. Some drivers have to change uniball arms after one race, take from that what you will. Uniballs have their place in the 4wd’ing community, and many racers will swear by them and the extra droop they allow.
This is one recent example of problems with a Camburg arm, post #27 onward;
http://www.fjcc.com.au/f36/bilstein-...12/index3.html
Upper arms binding on the coils (including the OEM arms) is a big issue, and it is technically illegal, and your vehicle can be defected because of it. Many will rotate the coils to sneak the arm in between coil windings, however, this is still illegal, and obviously undesirable from a mechanical perspective.
So what about ball joint upper arms?
There are newer design fixed (non-adjustable) ball joint arms (Blackhawk etc.) around now that can utilise the original OEM ball joint, however, their wheel alignment specs are not known or proven in lifted geometry. In the USA, this type of arm has on occasion had ball joints pop out due to poor fitting. Similar to claims of a fixed amount of caster in uniball arms, I simply don’t believe it until I see real wheel alignment figures.
When discussing the performance of after market ball joint arms, one must consider the OEM ball joint (90 deg included angular range of motion) binds at 575mm open length. This restricts the maximum strut open length to under 575mm, typically 570mm on the 120 series Prado.
There are after market ball joint arms such as SPC (camber and caster adjustable) that can allow droop past 575mm open length, right down to 589mm, which is CV bind. Not only will you have CV binding issues at such lengths, but at shorter lengths at 575mm, the CV boot is already folded and binding on itself, and rubs directly on the back of the strut ring eye. The tie rod ends will also have their boots stretched enough to weep grease. At 575mm, everything is already at the limits.
Keeping the strut length to underneath 575mm means less wear on everything, and if you are still running OEM arms, it means your suspension tops out on the struts rather than the ball joint, something which is not a good idea. Most running long struts on the 120 keep them in the 570-573mm range, before the OEM ball joint binds.
SPC arms were out of the question for me with a very lengthy history of major and ongoing problems. However, I really liked the concept of the adjustable ball joint and the large amount of caster that is reported in lifted geometry, up to 3.8deg caster at 85mm lift on the 120 IFS. Both of those figures are at the extreme end of what is possible for the IFS.
After speaking with another Pradopoint member who is running SPC arms, I was informed that Fulcrum have developed their own version of camber and caster adjustable arms.
These have already been in the market for a little while for 150/FJ’s, see here;
http://www.superpro.com.au/find/supe...999501238/vid-
As you can see from the Superpro catalogue, the new Fulcrum arms have been constructed in an OEM style look, and they run Superpro bushes. It’s definitely a plus to use urethane in the upper arm bushes and avoid twisting/tearing the Toyota rubber. Below is a photo of the arms on my 120;
The Fulcrum arms utilise a sliding camber slot, +/- 2 degrees, and an adjustable ball joint that can be rotated through four different positions to yield 0-4 degrees of caster adjustment. Both of these figures relate to non-lifted OEM ride height. The ball joint has an 85deg range of motion. The arms are folded steel, with a welded insert, and are considerably stronger than OEM. They are made in Victoria.
The principal engineering goal behind these Fulcrum arms is that they are road legal everywhere in Australia, as such they must not bind on the coils at full droop, and they are restricted to 50mm lift.
Fulcrum R&D is only 5min around the corner from me here in Brisbane, so I went and explained myself to the engineers, and I was very lucky to find they needed a 120 Prado to complete the testing phase on their 120 arms. I donated my 120 to them for a week, and they very generously supplied me with a free set of arms.
So what do I think about these new adjustable Fulcrum arms and what have I found for wheel alignment and ball joint bind?
Here is the alignment I have at the moment at 790mm ride height;
PS/DS
Camber -0.25deg/-0.24deg
Toe 1.2mm/1.1mm
Caster 2.81deg/2.30deg
SAI 12.56deg/12.32deg
Setback 0.09deg
I have a little more adjustment left, and can absorb some camber back through the arm slot to increase the caster slightly more, prolly not much more than 3deg. I’m running a 0.5deg caster split.
In caster terms, I’m quite happy with where the arms ended up. OEM specification is 2.67 +/- 0.75 degrees, so I’ve got the front end caster back to OEM spec. Handling wise my Prado feels significantly more settled at high speed.
To determine the geometry of the new Fulcrum arm, I did some strut/coil out IFS cycling measurements. Within 0.5mm, the Fulcrum ball joint binds the double wishbone at the same 575mm open length that the OEM ball joint binds at. The big difference of course is that the Fulcrum arms clear the coils.
Below is a photo of the Fulcrum arm at full droop on my 120 at 575mm open length (890mm bottom rim to guard), with a nice finger sized gap between the arm and the ball joint boot, and a finger sized gap between the tyre and arm.
There is also still plenty of clearance between the rear of the tyres and the guards. I’m currently running bfg 31’s. I’m sure 32’s will clear without any hassles.
So the Fulcrum arms tick a lot of important boxes. You can get OEM caster figures of at least 2.67deg back at 50mm lift. The ball joint binding at 575mm open length limits you to a strut open length shorter than 575mm, important for the wear and tear of everything in the IFS. The arms/ball joint boots clear the coils at full droop. They are considerably stronger than OEM arms. They utilise freely rotating Superpro bushes which won’t get stretched beyond its limits like rubber. These Fulcrum arms are Australian designed and built.
For the extremeophiles out there who want arms that droop below 575mm open length, and who like to lift up to 3” or more (and are not concerned about having limited droop), Fulcrum have indicated that in the future they will look into a longer travel ball joint. They will also look into moving the ball joint hole location on the adjustable plate further back, to obtain more caster at higher lifts.
For me personally, I don’t like lifting past 50mm on the IFS as after 790-800mm ride height you just loose droop due to the leverage ratio, even with the longest struts possible. So I’m very happy to keep running these Fulcrum arms with OEM caster figures up to 50mm lift, and keep my struts under 575mm and be kind to my IFS.
For those of you who like these Fulcrum arms and intend to give them a try, make sure your maximum strut open length is limited to a sensible 570mm.
Many thanks to Graham and the engineering team at Fulcrum, in particular Kirk, Scott and Nick who were hands on with my 120 and answered all my never ending questions!
Best
Mark
I’ve been struggling recently to get a decent amount of caster on my 120 with the OEM upper arms at a 790mm ride height. After recently finding my lower arm cams seized I replaced my lower arm bushes and after putting everything back together I was already rotating the rear PS cam almost right out to get just 1.5deg of caster. The front end handling was the worst I’ve ever had on my Prado, and I was pretty miffed with the wheel alignment after all the trouble of replacing seized up cam tubes.
As such, I started looking very closely at after market upper arms and what they could do, firstly in terms of caster (to improve high speed handling), and secondly in terms of what open length they bind up the double wishbone. Upper arm-Coil clearance at full droop is also a major criteria.
I’d already looked at upper arms previously just out of curiosity, and many of you will already be aware of the debate about uniballs vs ball joints.
My review of non-adjustable fixed caster uniball arms suggests that in lifted geometry they never give the amount of fixed caster claimed by the manufacturer. Uniballs suffer quickly from exposure to the elements and can end up losing material on the surface of the balls and rattle and squeak their way through a short service life. As usual, much of this information is from online forums, so these are reports of failures, and they always give a subjective opinion. A perhaps more rigorous assessment of uniballs comes from the desert racing community in the USA, where they are very popular. Some drivers have to change uniball arms after one race, take from that what you will. Uniballs have their place in the 4wd’ing community, and many racers will swear by them and the extra droop they allow.
This is one recent example of problems with a Camburg arm, post #27 onward;
http://www.fjcc.com.au/f36/bilstein-...12/index3.html
Upper arms binding on the coils (including the OEM arms) is a big issue, and it is technically illegal, and your vehicle can be defected because of it. Many will rotate the coils to sneak the arm in between coil windings, however, this is still illegal, and obviously undesirable from a mechanical perspective.
So what about ball joint upper arms?
There are newer design fixed (non-adjustable) ball joint arms (Blackhawk etc.) around now that can utilise the original OEM ball joint, however, their wheel alignment specs are not known or proven in lifted geometry. In the USA, this type of arm has on occasion had ball joints pop out due to poor fitting. Similar to claims of a fixed amount of caster in uniball arms, I simply don’t believe it until I see real wheel alignment figures.
When discussing the performance of after market ball joint arms, one must consider the OEM ball joint (90 deg included angular range of motion) binds at 575mm open length. This restricts the maximum strut open length to under 575mm, typically 570mm on the 120 series Prado.
There are after market ball joint arms such as SPC (camber and caster adjustable) that can allow droop past 575mm open length, right down to 589mm, which is CV bind. Not only will you have CV binding issues at such lengths, but at shorter lengths at 575mm, the CV boot is already folded and binding on itself, and rubs directly on the back of the strut ring eye. The tie rod ends will also have their boots stretched enough to weep grease. At 575mm, everything is already at the limits.
Keeping the strut length to underneath 575mm means less wear on everything, and if you are still running OEM arms, it means your suspension tops out on the struts rather than the ball joint, something which is not a good idea. Most running long struts on the 120 keep them in the 570-573mm range, before the OEM ball joint binds.
SPC arms were out of the question for me with a very lengthy history of major and ongoing problems. However, I really liked the concept of the adjustable ball joint and the large amount of caster that is reported in lifted geometry, up to 3.8deg caster at 85mm lift on the 120 IFS. Both of those figures are at the extreme end of what is possible for the IFS.
After speaking with another Pradopoint member who is running SPC arms, I was informed that Fulcrum have developed their own version of camber and caster adjustable arms.
These have already been in the market for a little while for 150/FJ’s, see here;
http://www.superpro.com.au/find/supe...999501238/vid-
As you can see from the Superpro catalogue, the new Fulcrum arms have been constructed in an OEM style look, and they run Superpro bushes. It’s definitely a plus to use urethane in the upper arm bushes and avoid twisting/tearing the Toyota rubber. Below is a photo of the arms on my 120;
The Fulcrum arms utilise a sliding camber slot, +/- 2 degrees, and an adjustable ball joint that can be rotated through four different positions to yield 0-4 degrees of caster adjustment. Both of these figures relate to non-lifted OEM ride height. The ball joint has an 85deg range of motion. The arms are folded steel, with a welded insert, and are considerably stronger than OEM. They are made in Victoria.
The principal engineering goal behind these Fulcrum arms is that they are road legal everywhere in Australia, as such they must not bind on the coils at full droop, and they are restricted to 50mm lift.
Fulcrum R&D is only 5min around the corner from me here in Brisbane, so I went and explained myself to the engineers, and I was very lucky to find they needed a 120 Prado to complete the testing phase on their 120 arms. I donated my 120 to them for a week, and they very generously supplied me with a free set of arms.
So what do I think about these new adjustable Fulcrum arms and what have I found for wheel alignment and ball joint bind?
Here is the alignment I have at the moment at 790mm ride height;
PS/DS
Camber -0.25deg/-0.24deg
Toe 1.2mm/1.1mm
Caster 2.81deg/2.30deg
SAI 12.56deg/12.32deg
Setback 0.09deg
I have a little more adjustment left, and can absorb some camber back through the arm slot to increase the caster slightly more, prolly not much more than 3deg. I’m running a 0.5deg caster split.
In caster terms, I’m quite happy with where the arms ended up. OEM specification is 2.67 +/- 0.75 degrees, so I’ve got the front end caster back to OEM spec. Handling wise my Prado feels significantly more settled at high speed.
To determine the geometry of the new Fulcrum arm, I did some strut/coil out IFS cycling measurements. Within 0.5mm, the Fulcrum ball joint binds the double wishbone at the same 575mm open length that the OEM ball joint binds at. The big difference of course is that the Fulcrum arms clear the coils.
Below is a photo of the Fulcrum arm at full droop on my 120 at 575mm open length (890mm bottom rim to guard), with a nice finger sized gap between the arm and the ball joint boot, and a finger sized gap between the tyre and arm.
There is also still plenty of clearance between the rear of the tyres and the guards. I’m currently running bfg 31’s. I’m sure 32’s will clear without any hassles.
So the Fulcrum arms tick a lot of important boxes. You can get OEM caster figures of at least 2.67deg back at 50mm lift. The ball joint binding at 575mm open length limits you to a strut open length shorter than 575mm, important for the wear and tear of everything in the IFS. The arms/ball joint boots clear the coils at full droop. They are considerably stronger than OEM arms. They utilise freely rotating Superpro bushes which won’t get stretched beyond its limits like rubber. These Fulcrum arms are Australian designed and built.
For the extremeophiles out there who want arms that droop below 575mm open length, and who like to lift up to 3” or more (and are not concerned about having limited droop), Fulcrum have indicated that in the future they will look into a longer travel ball joint. They will also look into moving the ball joint hole location on the adjustable plate further back, to obtain more caster at higher lifts.
For me personally, I don’t like lifting past 50mm on the IFS as after 790-800mm ride height you just loose droop due to the leverage ratio, even with the longest struts possible. So I’m very happy to keep running these Fulcrum arms with OEM caster figures up to 50mm lift, and keep my struts under 575mm and be kind to my IFS.
For those of you who like these Fulcrum arms and intend to give them a try, make sure your maximum strut open length is limited to a sensible 570mm.
Many thanks to Graham and the engineering team at Fulcrum, in particular Kirk, Scott and Nick who were hands on with my 120 and answered all my never ending questions!
Best
Mark
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