Diffdrop problems (1 Viewer)

[stellz996]

So i recently installed 1.0 inch thick spacers ontop of my fox 2.0 coil overs, the preload was backed off by 1 inch to keep the lift as close as possible to what it was before. Ofcourse this was causing some binding. The left hand shaft is a standard aftermarket shaft as its all i could get before christmas to replace one with a split boot, the right hand one is a 10mm extended shaft rated for up to a 4 inch lift.

The extended one had some minor binding at full droop and the new aftermarket one had really noticeable binding at full droop and still noticeable at ride howght on left turns.

Today i stuck a standard spacer style diff drop in hoping it would at least help but during a test drive i thought it felt worse, i jacked it up on axles stands and my thoughts were right, the right hand side is definetly worse at full droop and the left i can barely turn. (The left hand extended cv goes back in on the 9th and both sides get high angle and high clearance boots added at same time).

My problem is why is it worse now with the diff drop than before?

Right hand side ride hieght- 620mm
Right hand side full droop 670mm

Left hand side ride hieght 630mm
Left hand side full droop 670mm

All measurements center of hub to gaurd, i also think that considering i had 40-50mm of droop pre spacers and roughly the same now with the spacers that something is a bit off as i would have thought dropping the preload 25mm would give me around 80-90mm droop at least

 

[stellz996]

Both photos at ride height, using a free app on the phone best angle reading i could get was right side 11.2 degree and left side 15.4 degrees and yes the left side inner boot is destroyed

 

[mtnbiker4evr13]

I would think with what you've changed it would be "better" driving normally with the diff drop but the compressed/droop binding could be worse. This is assuming both CVs are not the issue due to wear/tear.

Reason on the compressed/droop is the diff spacer is pulling the relation of the diff output to LCA down which changes the CV angle relative to the LCA and increases the CV plunge as it cycles through the travel. Angles will be better in droop naturally but but are you binding on the outer due to angle or is the shaft hitting the cup? I can see having an extended shaft and diff drop making the cup contact worse by pushing the cv shaft further towards the cup. (Drawing not to scale... but shows the theory.)

...All that to say droop is likely the problem. Things already get tight at stock width with "mid" travel coilovers allowing more droop and your 1in spacer makes that even worse.

 

[stellz996]

So i have 2 oem cvs waiting to be picked up, they will be fitted with high angle inner and outer boots, at around $1300aud im hoping the problem will be sorted as the more i read the more it becomes apparent that most aftermarket cv's actually have less working angle than the toyota oem versions. Regarding wether its the inner or outer binding my guess would be inner as at full droop i get bind with the wheels strait

 

[stellz996]

I would think with what you've changed it would be "better" driving normally with the diff drop but the compressed/droop binding could be worse. This is assuming both CVs are not the issue due to wear/tear.

Reason on the compressed/droop is the diff spacer is pulling the relation of the diff output to LCA down which changes the CV angle relative to the LCA and increases the CV plunge as it cycles through the travel. Angles will be better in droop naturally but but are you binding on the outer due to angle or is the shaft hitting the cup? I can see having an extended shaft and diff drop making the cup contact worse by pushing the cv shaft further towards the cup. (Drawing not to scale... but shows the theory.)

I would think with what you've changed it would be "better" driving normally with the diff drop but the compressed/droop binding could be worse. This is assuming both CVs are not the issue due to wear/tear.

Reason on the compressed/droop is the diff spacer is pulling the relation of the diff output to LCA down which changes the CV angle relative to the LCA and increases the CV plunge as it cycles through the travel. Angles will be better in droop naturally but but are you binding on the outer due to angle or is the shaft hitting the cup? I can see having an extended shaft and diff drop making the cup contact worse by pushing the cv shaft further towards the cup. (Drawing not to scale... but shows the theory.)
View attachment 3229358
View attachment 3229364
...All that to say droop is likely the problem. Things already get tight at stock width with "mid" travel coilovers allowing more droop and your 1in spacer makes that even worse.

Hi mate, so providing the diff drop and oem cvs fix the binding their my next issue will be that my aftermarket ucas hit the coils now, even though the total coilover length of with the spacers added only increases 3mm over my previous coilovers which the same arms worked perfectly with. Appart from changing to a tube style uca and forking out more money than i can afford is there a way to eliminate the binding here. They are double adjustable at the chassis end but not adjustable at the ball, they are oversized joints so none of the extended joints available will fit either. Link below Superior Billet Alloy Upper Control Arms Suitable For Toyota Prado 120/150 Series (Pair) | Superior Engineering - https://www.superiorengineering.com.au/superior-billet-alloy-upper-control-arms-suitable-for-toyota-prado-120-150-series-34645?product_id=34645

View attachment 3229358
View attachment 3229364
...All that to say droop is likely the problem. Things already get tight at stock width with "mid" travel coilovers allowing more droop and your 1in spacer makes that even worse.

 

[mtnbiker4evr13]

At 13min mark there is good discussion about UCA coil clearance on UCA's.

That said, those Superior UCA's are gorgeous and appear to have tons of meat that could be taken down on the back side where you are having contact if you are really married to the coil spacer.

 

[stellz996]

At 13min mark there is good discussion about UCA coil clearance on UCA's.

That said, those Superior UCA's are gorgeous and appear to have tons of meat that could be taken down on the back side where you are having contact if you are really married to the coil spacer.

The spacers are actually a cheap way for me to test wether or not the coil overs i want will fit rather than buying a 500$ coil over on a guess. Superior tell me it is most likely an alignment issue as these arms are sold with there 4 inch lift kit witch uses 573mm extended length coil overs. While thier knowledge and customer service is usually great im wondering if this actually has any merit.

I am basically aiming to push the limit of mid travel, using 590mm extended length coil overs

 

[BMThiker]

That guy's YT channel is fantastic. He explains everything quite concisely with actual geometry.

 

[mtnbiker4evr13]

That guy's YT channel is fantastic. He explains everything quite concisely with actual geometry.

My engineering brain loves how he does each of his videos. So good!

 

[mtnbiker4evr13]

The spacers are actually a cheap way for me to test wether or not the coil overs i want will fit rather than buying a 500$ coil over on a guess. Superior tell me it is most likely an alignment issue as these arms are sold with there 4 inch lift kit witch uses 573mm extended length coil overs. While thier knowledge and customer service is usually great im wondering if this actually has any merit.

I am basically aiming to push the limit of mid travel, using 590mm extended length coil overs

That makes sense, basically the front version of your rear DIY long travel. With the Superior double adjustable UCA setup you could push the length out some via the adjusters and try to compensate on the alignment with what the LCA will allow. That might get some clearance at the coil but will be hard to get the positive camber out though.

I'd also say check out Tinker's YT videos on diff drops, long travel etc.. he does a beautiful job showing the suspension cycling while measuring CV angles at different amounts of droop with real numbers.

If I'm remembering correctly (parroting online measurements) things are going to get complicated past 9.5-10in of travel up front even with the goldilocks coilover. Going up the UCA is going to make contact with the inner fender before you run out of CV geometry or get metal to metal at the bump stop. Going down OEM UCA runs out of travel first at the ball joint, then with an aftermarket setup you can go all the way to CV axle contact at the diff cup like my first post. (all this at stock width).

With an arm style diff drop that gives a real 1" drop you might get the full 10" wheel travel from metal/metal on compression to full droop CV bind. With the usual little front spacer drops you're only going to get the drop of 1" sloped to the rear mounting points so ~.5" (12mm) of real "drop".

I love alternative setups, so very interested to see where you end up!

 

[stellz996]

That makes sense, basically the front version of your rear DIY long travel. With the Superior double adjustable UCA setup you could push the length out some via the adjusters and try to compensate on the alignment with what the LCA will allow. That might get some clearance at the coil but will be hard to get the positive camber out though.

I'd also say check out Tinker's YT videos on diff drops, long travel etc.. he does a beautiful job showing the suspension cycling while measuring CV angles at different amounts of droop with real numbers.

If I'm remembering correctly (parroting online measurements) things are going to get complicated past 9.5-10in of travel up front even with the goldilocks coilover. Going up the UCA is going to make contact with the inner fender before you run out of CV geometry or get metal to metal at the bump stop. Going down OEM UCA runs out of travel first at the ball joint, then with an aftermarket setup you can go all the way to CV axle contact at the diff cup like my first post. (all this at stock width).

With an arm style diff drop that gives a real 1" drop you might get the full 10" wheel travel from metal/metal on compression to full droop CV bind. With the usual little front spacer drops you're only going to get the drop of 1" sloped to the rear mounting points so ~.5" (12mm) of real "drop".

I love alternative setups, so very interested to see where you end up!

I do watch his videos, and uave watched his uca and diff drop and ones. Handling the compression side of things is easy, with the spacers the travel range is moved down full compression is further from the fender, the spacers also require bumpstop spacing so again compression is moved away from the fender. I did think about moving the uca outwards and as my lca's are seized i will likely by installing the superpro versions which have double offset bushes which i believe ad a few more degrees of camber adjustment. Maybe this will fix the coil bind, i dont see my self reaching 10 inches of travel, though, looking at 3 inches of lift and 4-5 inches of droop at the wheel

 

[stellz996]

That makes sense, basically the front version of your rear DIY long travel. With the Superior double adjustable UCA setup you could push the length out some via the adjusters and try to compensate on the alignment with what the LCA will allow. That might get some clearance at the coil but will be hard to get the positive camber out though.

I'd also say check out Tinker's YT videos on diff drops, long travel etc.. he does a beautiful job showing the suspension cycling while measuring CV angles at different amounts of droop with real numbers.

If I'm remembering correctly (parroting online measurements) things are going to get complicated past 9.5-10in of travel up front even with the goldilocks coilover. Going up the UCA is going to make contact with the inner fender before you run out of CV geometry or get metal to metal at the bump stop. Going down OEM UCA runs out of travel first at the ball joint, then with an aftermarket setup you can go all the way to CV axle contact at the diff cup like my first post. (all this at stock width).

With an arm style diff drop that gives a real 1" drop you might get the full 10" wheel travel from metal/metal on compression to full droop CV bind. With the usual little front spacer drops you're only going to get the drop of 1" sloped to the rear mounting points so ~.5" (12mm) of real "drop".

I love alternative setups, so very interested to see where you end up!

Suppose i was to have the lower spindle mounts extended an inchand use longer bolts, would that move the whole set up upwards or would it just move the mounting points lower

 

[NyNomad]

you don't need a diff drop unless the front lift is Over 3inches. 3inches below, not needed

 

[stellz996]

I am currently running 4.5 but will be bringing it down to 3-3.5, the coil over open length is more important than lift hieght when talking about diffdrops. Did you read the whole whole thread? I have cv binding at ride hieght turning left and with wheels strait at full droop. So yes i need a diffdrop and genuine cv joints with high angle boots. I could run 0 inches of lift I would still jave binding at full droop, if i ran stock coil overs at 4 inches of lift i would get no binding at all, hence the open length is more important than lift hieght when talking about whether or not diffdrops are needed

 

[mtnbiker4evr13]

Suppose i was to have the lower spindle mounts extended an inchand use longer bolts, would that move the whole set up upwards or would it just move the mounting points lower

If I'm picturing what you're saying correctly, basically put a 25mm spacer between the lower ball joint and the spindle?

Then that would "drop" the ride height by that same amount BUT while you would eliminate your full droop CV bind... you would also put your upper control arm ~25mm closer to the inner fender at full bump. Kinda doing the same thing as the drop brackets/extended spindles on the usual 4in lift systems.

If the closed eye to eye dimension on the 590mm coilovers can't use that last inch then that be a good compromise. Limit straps prior to CV bind might be an option too.

IFS is fun trying to balance packaging, travel and geometry haha. Question though, what are we wanting standard coilovers for?

-cheaper coilover?
-more wheel travel for slow speed crawling?
-more wheel travel for fast bumps?

The answer there will dictate what trade offs are acceptable. Hard to beat some decent mid travel coilovers for an all around setup.

 

[stellz996]

If I'm picturing what you're saying correctly, basically put a 25mm spacer between the lower ball joint and the spindle?

Then that would "drop" the ride height by that same amount BUT while you would eliminate your full droop CV bind... you would also put your upper control arm ~25mm closer to the inner fender at full bump. Kinda doing the same thing as the drop brackets/extended spindles on the usual 4in lift systems.

If the closed eye to eye dimension on the 590mm coilovers can't use that last inch then that be a good compromise. Limit straps prior to CV bind might be an option too.

IFS is fun trying to balance packaging, travel and geometry haha. Question though, what are we wanting standard coilovers for?

-cheaper coilover?
-more wheel travel for slow speed crawling?
-more wheel travel for fast bumps?

The answer there will dictate what trade offs are acceptable. Hard to beat some decent mid travel coilovers for an all around setup.

I dont want standard coil overs at all. Not quite between the ball joint and spindle but between the spindle mount its self. The way i pictured it working would be that it lifted everything but he coilover away from the lower control arm so yes, the upper arm would get closer to fender but the tyre would hit well before the arm. Would be the equivalant of running an extended balljoint. I could be wrong here and maybe im better off at finding a way to lift the uca higher than the spindle mount, The 4 inch brackets move the the hub downwards rather than the moving it upwards, so ground clearance is gained

 

[stellz996]

I did consider limit straps but im hoping there is more travel to be gained we i can overcome the cv bind and coilover bind, of course if theres not then straps will to the job

 

[NyNomad]

3" really is max recommended unless going long travel

 

[stellz996]

3" really is max recommended unless going long travel

Thats generally wat im aiming for as it will give me around 11inches of clearance even with diffdrop installed

 

[-MaTTi-]

No bind here, 4” lift, 8.5” travel:

Rough Country 3” dropped crossmembers and 3” longer spindles, FOX 2.5 coilovers with 16” Eibach springs: