Bigger tires and the limits of an SYA KIT

[Trist]

I hope you’re well. I’m currently finalizing my wheel and tire setup and wanted to share my current plan to see if anyone might have any final thoughts or recommendations.
After doing extensive research, here’s the configuration I’m aiming for on the 2015 3.0 TDV6 D4:


Tires: 275/70R18 (~33.2”)
Lift: SYA kit only (no lift rods or X-Lifter)
Wheels: 18x9, ET20–25(30) (ideally Compomotive PD1881)
Reasoning & Understanding:The SYA kit redefines the ECU’s zero point and provides a true ~1.5/2” mechanical lift, without increasing pressure on the air struts or limiting suspension travel. In my understanding a SYA + rhino rods pushes struts near or beyond design limits adding bushing preload and ride harshness, and isn't ideal for daily driver. You would have a so called double lift and need a IID GAP TOOL to rebalance out by 0.5 inch. I could be way off here but using the SYA kit and limiting straps(included) there's simply no need for a pressure lifted system like the rhino rods on top of that. The vehicle clears the tires and gives you sweet dreams knowing it won't lay on its tires in case of failure.

However it is necessary if you ran a lift rod setup, the SYA bracket moves the sensor mount higher, so the sensor thinks it's lower than it really is. This allows the strut to sit in a more neutral position, even when the ECU thinks it's at “normal height”. You get the lifted ride height without the strut being overinflated. Less internal pressure = Less bellow expansion = longer strut life.


I also understand I’m right at the edge with this tire size, but from what I gather, it’s a viable and stable setup for both daily and off-road use when combined with
(feedback about trimming zones or alignment settings I should be aware of is appreciated):


Fender liner trimming (front bottom corner)

Possible frame horn cutting (if required at full lock)

Rear liner heat gun work or light trimming

Proper re-torque of suspension arms at new static height (to avoid premature bushing wear)



I want to avoid wheel spacers and prefer a direct-fit wheel in the correct offset range.
My goal is a functional, clean build that maintains comfort and geometry while gaining ground clearance and sidewall + arch presence.
Based on your experience, do you have any additional suggestions or concerns about this setup or would you recommend any other specs that hit the same balance between fitment, strength, and availability?

[DieselLSE]

Why? Where will you be going that 18" wheels, 260 x 60 x 18 LT tyres and a LLAMS kit won't get you? This kit will get you anywhere in Australia (and probably Africa as well). And yes, I always fit a bull bar and winch just in case. What part of Belgium is so rough and remote?

[loanrangie]

Complete waste of time, i cant see how it provides a zero ECU point when it pushes the arms down mechanically which will limit travel.
An electronic lifter and moderate 265/65/18 or even 275/65/18 will provide more than enough clearance.

[Tombie]

I love a good "monster" truck... I've built a couple of them over the years.

What they are is a vehicle full of compromises... most of them negative.

SYA kits push arms down mechanically, forcing CV joints into a permanent state of stress. wear and risk of failure at these points then becomes high.
They drive like crap, they will track all road ruts, they stress wheel bearings with oversize rubber, they cheew fuel, lack acceleration... the list goes on.

If you want a monster tyred 4x4 start with something else...

[DiscoDB]

You will probably have more luck searching the US forums where those kits seem to be more popular.

Lucky 8 SYA Kit Problem | Land Rover and Range Rover Forums (https://www.landroverworld.org/threads/lucky-8-sya-kit-problem.42939/)

New air struts and Lucky 8 SYA kit | Land Rover and Range Rover Forums (https://www.landroverworld.org/threads/new-air-struts-and-lucky-8-sya-kit.42694/)

SYA Kit, Oversize Tires and Stability Control | Land Rover and Range Rover Forums (https://www.landroverworld.org/threads/sya-kit-oversize-tires-and-stability-control.43087/)

[Trist]

Complete waste of time, i cant see how it provides a zero ECU point when it pushes the arms down mechanically which will limit travel.
An electronic lifter and moderate 265/65/18 or even 275/65/18 will provide more than enough clearance.

Do you mean the kind of lift rods that increase pressure and preload? I agree those can be problematic, as I have mentioned in my Post.
What I’m referring to is the SYA kit that physically repositions the sensor bracket and bump stops, so the vehicle rides higher with lower air pressure.
It’s not like a +2” static rod lift. Curious if you’ve seen the difference between these approaches in practice?

[Trist]

I love a good "monster" truck... I've built a couple of them over the years.

What they are is a vehicle full of compromises... most of them negative.

SYA kits push arms down mechanically, forcing CV joints into a permanent state of stress. wear and risk of failure at these points then becomes high.
They drive like crap, they will track all road ruts, they stress wheel bearings with oversize rubber, they cheew fuel, lack acceleration... the list goes on.

If you want a monster tyred 4x4 start with something else...

Totally agree that extreme lifts can ruin the geometry.
That’s why I’m trying to stay conservative: ~1.5” static lift with struts at normal pressure, no added rods or height stacking, careful trimming, and suspension re-torque.
My goal is more long-term geometry and comfort, not a showpiece on 35s. Any experience with this specific SYA kit design from Lucky8/Proud Rhino?

[Trist]

Why? Where will you be going that 18" wheels, 260 x 60 x 18 LT tyres and a LLAMS kit won't get you? This kit will get you anywhere in Australia (and probably Africa as well). And yes, I always fit a bull bar and winch just in case. What part of Belgium is so rough and remote?

My goal here is more of a static solution: I want to retain full range of air suspension without stressing struts long-term. Balance the disco's comfortable looks, geometry and off-road ability.
Not at all aiming for extreme clearance or rock-crawling, it's just not the cars habitat or purpose.
Belgium isn’t wild, but our convoy terrain includes a lot of mud, wet forestry and deep ruts that benefit from a 33” + sidewall.

There's just no purpose replacing 255/55/19's with 260/60/18's for the 0.8% difference and 5k in cost. Neither is there for a LLAMS kit running 770mm's, the default EAS is capable enough as it is.
The post obviously refers to a SYA kit usage without rods, the replies are just straight negativity instead of answering my question/giving experienced feedback.

[discomatt69]

Never seen these kits , how do they lift the car without increasing bag pressure?
to achieve that do they have a spacer under the bag or something?
just moving sensors, changing rods or bump stops doesn’t change height without changing airbag pressure
is it a body lift?

[Graeme]

Air-spring height is achieved using increased air volume, not pressure. Pressure increases with added weight.

[DiscoDB]

Never seen these kits , how do they lift the car without increasing bag pressure?
to achieve that do they have a spacer under the bag or something?
just moving sensors, changing rods or bump stops doesn’t change height without changing airbag pressure
is it a body lift?

The SYA kit is basically a spacer which sits between the top of the airbag and the chassis/body. So you achieve a lift at the same bag/shock extension.

The maximum lift is still limited due to the geometry of the suspension/drive train hence they also come with straps to stop over-extending when you pick up a wheel off the ground.

The maximum lift achieved appears to be no greater than what we can achieve say using the GapIID tool to reset the height, but the benefit is it gives the body extra lift when on the bump stops (which also get spacers to raise the height) so you can fit larger tyres with less concern about dropping the body onto the wheels when the air suspension fails.

This type of mod seems to be popular in North America where some very extreme rocky trail tracks are tackled and you want as much lift as you can get. I can’t imagine many of these kits have been sold into Australia. Never seen a post here on these before, but they get discussed a lot on Landroverworld.org.

[loanrangie]

Do you mean the kind of lift rods that increase pressure and preload? I agree those can be problematic, as I have mentioned in my Post.
What I’m referring to is the SYA kit that physically repositions the sensor bracket and bump stops, so the vehicle rides higher with lower air pressure.
It’s not like a +2” static rod lift. Curious if you’ve seen the difference between these approaches in practice?

No not rods, electronic like llams/easy lift etc. You don't need the SYA kit if all you want is 1.5" of lift.

[DiscoJeffster]

Air-spring height is achieved using increased air volume, not pressure. Pressure increases with added weight.

Not 100% correct. Pressure also increases as does volume as the bag expands. I get your point but there is an increase in pressure as well.

[DiscoDB]

Air-spring height is achieved using increased air volume, not pressure. Pressure increases with added weight.

I ran +40mm height for a while (when having suspension fault issues which would see the car regularly drop to a lowered height) and I very much liked how it “firmed” up the ride with the extra volume of air.

[DiscoDB]

My goal here is more of a static solution: I want to retain full range of air suspension without stressing struts long-term. Balance the disco's comfortable looks, geometry and off-road ability.
Not at all aiming for extreme clearance or rock-crawling, it's just not the cars habitat or purpose.
Belgium isn’t wild, but our convoy terrain includes a lot of mud, wet forestry and deep ruts that benefit from a 33” + sidewall.



If the aim is just to run the largest tyres you can and not for extreme rock crawling, I would be more inclined to program a 40mm lift with the GapIID tool to reset the normal height, and then look into just adding bump stop height extensions so when the suspension faults it doesn’t run the risk of the body sitting on the wheels.

The largest tyre size I have read anyone running on the D4 on this forum was 32” (275/65R18).

[Trist]

If the aim is just to run the largest tyres you can and not for extreme rock crawling, I would be more inclined to program a 40mm lift with the GapIID tool to reset the normal height, and then look into just adding bump stop height extensions so when the suspension faults it doesn’t run the risk of the body sitting on the wheels.

The largest tyre size I have read anyone running on the D4 on this forum was 32” (275/65R18).

Would a 285/65/18 work, only one available in my country...