Whitey
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Hi everyone,
I have used the Bilstein BE5-A712/Ridepro ZC7296 combination on the Prado 120 IFS (2006 petrol/auto GXL) for some years, which has been troublesome from the start. I have found the BE5-A712 struts are too short with open length = 553mm, which results in topping out of the strut and bunny-hopping around corners/roundabouts/over speed bumps etc. Initially I had ZC7300 coils (385mm free length), which yielded only 35mm droop. Changing to ZC7296 (378mm free length) coils achieved 50mm droop. Similar low droop measurements of 35mm have been reported for OEM TEMS/King combinations, and 35-45mm for Bilstein/King combinations. Further, my ZC7296 coils have sagged and I’ve lost 0.85” lift in 1 year, increasing droop to 75mm, but the struts still top-out.
Here is a plot with some droop measurements for various shock/coil combinations;
Several users have reported IFS droop in the 70-100mm range, and I personally think after my own experience (and shortened shock life due to topping out) that there is no point lifting 2” or more without achieving this kind of front droop. As such, long travel shocks and perhaps UCA replacement appear critical to achieve maximum front droop, even in a 2” lift.
I’ve seen the commonly reported figure of 60mm (dashed line in the plot) as being the minimum droop required to avoid topping out shocks. Note that my BE5-A712 struts still top-out regularly with 75mm of droop. Just to make sure there was nothing peculiar with my setup, I spent the time and carefully measured my shock lengths and wheel travel.
Below I’ve plotted my Shock length vs Wheel travel/Droop for the IFS;
As you can see, my measurements agree closely with the commonly reported 1:2 leverage ratio for shock:wheel travel for the Prado 120, giving a motion ratio of about 0.45 for the IFS from my measurements (1:2.2). The plot also suggests around 105mm droop can be achieved at the maximum shock length of 570mm. I know of at least one user who has reported 100mm droop from an N140S strut with open length = 570mm. I would really like to see measurements from users with different shock/coil combinations, particularly long travel struts out to 570mm. I’m happy to update this plot with different shock/coil combinations.
After doing my measurements, I want to ask the ‘minimum 60mm droop question’ in reverse. What is the minimum open length on a front strut to avoid the bunny hopping/wheel lifting which I have experienced constantly with the BE5-A712 struts for several years. Have users experienced hopping/lifting on struts longer than 553mm?
This also has me wondering about the OEM setup. The factory strut is 420mm/540mm on a 370mm coil. Can anyone report instances of topping out this strut in an OEM vehicle with no accessories? Does anyone know the maximum droop on the OEM setup?
Many off-road forums state the optimal configuration for off-road performance vehicles as 30-50% up-travel, but this is not achievable in the IFS setup on the Prado. Shock down-travel is limited to approximately 570mm before CV binding occurs. In my setup, I have 73% up-travel (92mm) and 27% down-travel (34mm) from my stationary level ride height. I’d be very interested to hear the ratios from other setups, but I cannot see the ratio changing by very much (due to max down-travel of around 50mm), so it seems we are quite limited with minimal down-travel on the Prado IFS.
I am considering three options at the moment to replace my flogged out Bilstein/Ridepro combination; i) spend 4K+ on custom length 10-way adjustable remote-res King shocks, ii) spend 2K+ on adjustable Koni (88-1712/88-1689) shocks, or iii) the cheapest option at around 1K+, Lovells long travel (64610087F/64612489) shocks. I’m mulling over using Dobinson (C59-302/C59-327) springs. I’m still concerned that 395mm/617lb/in coils will still sag too much, and I’d like to hear what other users think is the optimal coil length/spring rate to maintain 2” lift with an ARB bar. I’m happy with a 2” lift, but I want maximum droop, minimal sag over time, and no shock bottom/topping-out.
As a general precaution for shock selection for the 120, users should also be aware of the CV binding 570mm shock travel limit on the IFS, and the 615mm swaybar limited shock travel on the rear end. Choosing extended travel shocks (even on a 2” lift) should avoid shock bottoming/top-out in most driving situations (unless a wheel is in the air etc.). A diff drop on the IFS will also keep your CV angles healthy, and give them a longer working life, even at 2” lift.
Look forward to hearing everyone’s thoughts.
Best from the Bris
Mark
I have used the Bilstein BE5-A712/Ridepro ZC7296 combination on the Prado 120 IFS (2006 petrol/auto GXL) for some years, which has been troublesome from the start. I have found the BE5-A712 struts are too short with open length = 553mm, which results in topping out of the strut and bunny-hopping around corners/roundabouts/over speed bumps etc. Initially I had ZC7300 coils (385mm free length), which yielded only 35mm droop. Changing to ZC7296 (378mm free length) coils achieved 50mm droop. Similar low droop measurements of 35mm have been reported for OEM TEMS/King combinations, and 35-45mm for Bilstein/King combinations. Further, my ZC7296 coils have sagged and I’ve lost 0.85” lift in 1 year, increasing droop to 75mm, but the struts still top-out.
Here is a plot with some droop measurements for various shock/coil combinations;
Several users have reported IFS droop in the 70-100mm range, and I personally think after my own experience (and shortened shock life due to topping out) that there is no point lifting 2” or more without achieving this kind of front droop. As such, long travel shocks and perhaps UCA replacement appear critical to achieve maximum front droop, even in a 2” lift.
I’ve seen the commonly reported figure of 60mm (dashed line in the plot) as being the minimum droop required to avoid topping out shocks. Note that my BE5-A712 struts still top-out regularly with 75mm of droop. Just to make sure there was nothing peculiar with my setup, I spent the time and carefully measured my shock lengths and wheel travel.
Below I’ve plotted my Shock length vs Wheel travel/Droop for the IFS;
As you can see, my measurements agree closely with the commonly reported 1:2 leverage ratio for shock:wheel travel for the Prado 120, giving a motion ratio of about 0.45 for the IFS from my measurements (1:2.2). The plot also suggests around 105mm droop can be achieved at the maximum shock length of 570mm. I know of at least one user who has reported 100mm droop from an N140S strut with open length = 570mm. I would really like to see measurements from users with different shock/coil combinations, particularly long travel struts out to 570mm. I’m happy to update this plot with different shock/coil combinations.
After doing my measurements, I want to ask the ‘minimum 60mm droop question’ in reverse. What is the minimum open length on a front strut to avoid the bunny hopping/wheel lifting which I have experienced constantly with the BE5-A712 struts for several years. Have users experienced hopping/lifting on struts longer than 553mm?
This also has me wondering about the OEM setup. The factory strut is 420mm/540mm on a 370mm coil. Can anyone report instances of topping out this strut in an OEM vehicle with no accessories? Does anyone know the maximum droop on the OEM setup?
Many off-road forums state the optimal configuration for off-road performance vehicles as 30-50% up-travel, but this is not achievable in the IFS setup on the Prado. Shock down-travel is limited to approximately 570mm before CV binding occurs. In my setup, I have 73% up-travel (92mm) and 27% down-travel (34mm) from my stationary level ride height. I’d be very interested to hear the ratios from other setups, but I cannot see the ratio changing by very much (due to max down-travel of around 50mm), so it seems we are quite limited with minimal down-travel on the Prado IFS.
I am considering three options at the moment to replace my flogged out Bilstein/Ridepro combination; i) spend 4K+ on custom length 10-way adjustable remote-res King shocks, ii) spend 2K+ on adjustable Koni (88-1712/88-1689) shocks, or iii) the cheapest option at around 1K+, Lovells long travel (64610087F/64612489) shocks. I’m mulling over using Dobinson (C59-302/C59-327) springs. I’m still concerned that 395mm/617lb/in coils will still sag too much, and I’d like to hear what other users think is the optimal coil length/spring rate to maintain 2” lift with an ARB bar. I’m happy with a 2” lift, but I want maximum droop, minimal sag over time, and no shock bottom/topping-out.
As a general precaution for shock selection for the 120, users should also be aware of the CV binding 570mm shock travel limit on the IFS, and the 615mm swaybar limited shock travel on the rear end. Choosing extended travel shocks (even on a 2” lift) should avoid shock bottoming/top-out in most driving situations (unless a wheel is in the air etc.). A diff drop on the IFS will also keep your CV angles healthy, and give them a longer working life, even at 2” lift.
Look forward to hearing everyone’s thoughts.
Best from the Bris
Mark
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