Bump in High Mode – Suspension Topping Out?

[lx570westtexas]

Hey everyone,

Hoping to learn from some of the more experienced folks here — I’m experienced enough with my rig to know when something feels different but when it comes to suspension systems, I am way out of my depth.

I have a 2014 LX 570 with stock AHC (which I love), around 96k miles, and it’s mostly stock. Lately I’ve noticed that when off-roading in High mode, I get a noticeable bump when the front suspension is fully extended, like when a front wheel drops into a rut or off a rock. It doesn’t happen at normal height, so I’m guessing it’s related to the suspension being at full droop in High mode.

Is this just the shocks topping out? Could it be a normal behavior in High, or does this point to worn dampers or something else in the AHC system?

I haven’t done any AHC mods or lifts. Everything looks intact visually, and the ride still feels great in Normal mode. I just want to make sure I’m not damaging anything, and I’d love to understand better what’s going on. I can take it to my Toyota mechanic or I can take it to an off-road place. I want to retain the AHC system and either replace or upgrade with similar outstanding long lasting Toyota parts.

I’m not really sure where to start. I have been noticing that the AHC system seems to droop more quickly so I was thinking about replacing that fluid. But I think I have a worn out something in the suspension or shocks.

Any advice or shared experiences would be really appreciated. Thanks

 

[Heckraiser]

Yes, that is probably your AHC shock topping out. Do you have a sensor lift? Mine had a little clunking noise as well. The solution is to add a strut spacer up front to extend the suspension travel a little bit. The 10mm Toyota spacer would work, E&E offroad sells a 13mm one (which is the maximum spacer you can add without changing out the top hat studs). There are ways to fit even larger spacers, up to 20mm if you really want to maximize suspension travel.

Changing fluid is a good idea if you don't know when it was done last. Replacing accumulator globes is also pretty standard maintenance at ~150k+ miles, but these probably wont fix your clunk.

Lots of good reading here, if you want to wade through it all:

Thread 'Long Travel AHC'

Jun 21, 2022

Probably no surprise, but I've been a big proponent oh AHC. Damping always dialed in regardless of load. Large fluid volumes and remote accumulator damper that stays cool with extended off-road travels. Actively pressurized for long term performance and durability. Combined with unique traits of adjustable height, load handling, and multi-rate springs for anti-brake dive and handling, there's a lot going for it.

But where does it come up short? Suspension travel due to shock length. Because length dictates maximum suspension droop of the suspension, it has until now limited travel...

• TeCKis300
• Replies: 702
• Forum: 200-Series Cruisers

• 

 

[lx570westtexas]

Yes, that is probably your AHC shock topping out. Do you have a sensor lift? Mine had a little clunking noise as well. The solution is to add a strut spacer up front to extend the suspension travel a little bit. The 10mm Toyota spacer would work, E&E offroad sells a 13mm one (which is the maximum spacer you can add without changing out the top hat studs). There are ways to fit even larger spacers, up to 20mm if you really want to maximize suspension travel.

Changing fluid is a good idea if you don't know when it was done last. Replacing accumulator globes is also pretty standard maintenance at ~150k+ miles, but these probably wont fix your clunk.

Lots of good reading here, if you want to wade through it all:

Thread 'Long Travel AHC'

Jun 21, 2022

Probably no surprise, but I've been a big proponent oh AHC. Damping always dialed in regardless of load. Large fluid volumes and remote accumulator damper that stays cool with extended off-road travels. Actively pressurized for long term performance and durability. Combined with unique traits of adjustable height, load handling, and multi-rate springs for anti-brake dive and handling, there's a lot going for it.

But where does it come up short? Suspension travel due to shock length. Because length dictates maximum suspension droop of the suspension, it has until now limited travel...

• TeCKis300
• Replies: 702
• Forum: 200-Series Cruisers

• 

Thank you so much for your input. I do not have a sensor lift.

I’ll look into getting the spacer replaced. Not sure if I can do it myself but I’ll look into it.

Ahc fluid change or globes replaced? Which one should I do at 96k? I’ve noticed it’s dropping quicker that normal.

 

[Heckraiser]

At your mileage, I would do the fluid change first. It's supposed to be a 60k service. Your globes may be starting to lose some of their capacity, but IMO, if you're happy with the ride, I would leave them alone. When they really start to go, you'll feel it in the form of a harsh ride and little/no distinction between comfort/normal/sport.

 

[lx570westtexas]

At your mileage, I would do the fluid change first. It's supposed to be a 60k service. Your globes may be starting to lose some of their capacity, but IMO, if you're happy with the ride, I would leave them alone. When they really start to go, you'll feel it in the form of a harsh ride and little/no distinction between comfort/normal/sport.

Thank you for your help!

 

[riffman12]

I had this issue on my LX470 back in the day and it drove me nuts. Even after changing fluid (and eventually globes) the issue never went away.

It would happen when cruising on a bumpy trail in high mode. Shocks topped out and made a big clunk. It made it so I couldn't really use high mode unless I was crawling in 1st/2nd gear

Curious to see if others have had this issue with the 570 and how they remedied it

 

[lx570westtexas]

I had this issue on my LX470 back in the day and it drove me nuts. Even after changing fluid (and eventually globes) the issue never went away.

It would happen when cruising on a bumpy trail in high mode. Shocks topped out and made a big clunk. It made it so I couldn't really use high mode unless I was crawling in 1st/2nd gear

Curious to see if others have had this issue with the 570 and how they remedied it

That's worrying! I hope others can chime in if they've had something similar happen. Trying to crowd source LX 570 owners who understand AHC and offroading.

 

[TeCKis300]

It's not an issue per say. Every suspension has max droop limits. While it's perceptible, it shouldn't be a loud clunk or anything.

This can be more annoying for some setups and tuning. The LX470 with its shorter suspension travel was notorious for limited droop travel in AHC high mode. The LX570 does retain more down travel stock, but once sensor lifting, can result in limited droop travel. As pointed out earlier, the suspension can be augmented for more down travel which will greatly increase its slinkiness and reduce topping out.

AHC damper modes can also as Comfort is going to have the least amount of rebound damping, with Sport having the most. It may be counter intuitive but I rarely use Comfort off-road these days as I'm more aggressive and want the additional damping and body control.

For reference from this thread:

Thread 'Suspension Travel Comparison'

Nov 8, 2020

Been meaning to do this to get some objective numbers to compare ride height versus droop travel versus compression travel. What better to do on a rainy day.

Hope is that others may contribute and I'll update my table. We've known for awhile that some aftermarket suspensions increase what is already excellent droop travel. OEM spacer added to an otherwise stock LC or LX suspension increases travel at the front. Even though LC and LX differ in suspension fitted, the overall geometry and travel should be very similar or exactly the same.

All measurements are from wheel center to...

• TeCKis300
• Replies: 84
• Forum: 200-Series Cruisers

• 
• 

Front Measured Ride Height	Front Measured Max Compression	Front Measured Max Droop	Front Compression /Droop Travel	Front Total Travel	Rear Measured Ride Height	Rear Measured Max Compression	Rear Measured Max Droop	Rear Compression /Droop Travel	Rear Total Travel
LX stock	N-19" H-21"	*16"	24.5"	N-3.5"/5.5" H-5.5"/3.5"	*8.5" or ~9"	N-20.75" H-23.1"	-	26.63"	N-4.12"/5.88" H-6.5"/3.5"	~10"
LX - .75F/.5R Sensor Lift, OEM Front Spacer [COLOR=rgb(255, 220, 133)]@TeCKis300[/COLOR]	N-19.8" H-21.8"	*16"	25.375"	N-4.4"/5.6" H-6.4"/3.6"	*9.4" or ~10"	N-21.25" H-23.63"	*17.5"	26.63"	N-4.6"/5.4" H-7"/3.0"	*9.1" or ~10"
LX AHC Long Travel - 1.5F/1R Sensor Lift, LC OEM Spacer (10mm) + stacked 6.5mm spacer, 1" extended AHC shocks	N-20.75" H-22.75"	*16"	25.75"	N-5"/5.5" H-7"/3.5"	10.5"	N-22" H-24.35"	*17.5"	27.375"	N-5.12"/5.88" H-7.5"/3.4"	11"

 

[LUXCRUZ]

I have had this exact same issue with the suspension topping out after a mild tech stream and sensor lift. I have installed a Westcott designs 200 series preload kit on the front as well as their spring spacer in the rear. In the rear, I installed E&E off-road shock risers and that gave me about 1.5 inches more droop in the rear. Even with a pretty significant lift in the rear, I have no issues with topping out. I ended up dropping the front down so it’s in a bit of a stink bug position now. Even with that, I’m still having problems with the front. Mainly when you lift it into high mode with the AHC the system over raises the front to basically the max. And then as you drive it, it drops about 3/4 to 1 inch. Which seems to be tolerable. I’m not sure why I’m having this issue. I may have to recalibrate with text stream to the stock height again and start over.

I also feel like I have zero rebound control, even with all new accumulators. I am attributing that to the lift, heavy tires and preload kit. But I was considering replacing the shocks to see if it helps at all.

As a sidenote, I was wondering if anybody has ever considered using limit straps like some of the LC guys.

Let me know what you guys think. Thanks!

 

[LUXCRUZ]

Also, I believe that the spacer on the top of the front strut that comes with the Westcott designs kit is about 10 or 15 mm. You can’t see it in the photo.