Hey everyone,
After spending many hours hunting down OEM coil spring rates for various old and new vehicles, I thought it would be a great idea to keep a table of OEM rates for Toyota 4wd vehicles.
There are two figures for the coil spring rates, the first is calculated from the spring rate equation;
G = torsional modulus = 75800N/mm2 (spring steel)
d = wire diameter
Na = number active coils
Dm = mean diameter = inside diameter + wire diameter
Using industry standard, the number of inactive coils is 0.75 at each end, or 1.5 in total. This is the same no matter the type of end, ground flat or open. You can also note that the 0.75 inactive end approximation is always quite close by observing the marks on the coil ends where they rub on the coil buckets. The wire diameter should be measured on every coil wrap and then averaged, as the diameter can vary by up to 0.5mm across all coil wraps. Note my measurements now exclude the powder coat.
120/Hilux/150/FJ coils;
Landcruiser coils;
The second figure for OEM coil spring rate has been determined by load testing at King Springs. Here is a video showing how Dobinsons manufacture their coils, you can see the load testing performed at the 4:20 mark, where the coil is fully 100% compressed to solid coil height;
https://www.youtube.com/watch?v=en8Q...&nohtml5=False
Many thanks to John at Zordos Suspension for providing OEM coils for measurements, and to Steve at King Springs for load deflection testing of 12 coils.
If anyone has their pre 2015 OEM 150 petrol coils, if you’re willing to donate them to my coil collection could you PM me so I can complete the table. I’d also like to get some earlier Hilux coils from 05/06, as I suspect they have changed free height and spring rate slightly up to the 2015 coils I have measured. Same applies for Landcruiser coils, if you have some, please let me know!
This is a work in progress, so I’ll update the table every time I get some new data.
Best
Mark
After spending many hours hunting down OEM coil spring rates for various old and new vehicles, I thought it would be a great idea to keep a table of OEM rates for Toyota 4wd vehicles.
There are two figures for the coil spring rates, the first is calculated from the spring rate equation;
G = torsional modulus = 75800N/mm2 (spring steel)
d = wire diameter
Na = number active coils
Dm = mean diameter = inside diameter + wire diameter
Using industry standard, the number of inactive coils is 0.75 at each end, or 1.5 in total. This is the same no matter the type of end, ground flat or open. You can also note that the 0.75 inactive end approximation is always quite close by observing the marks on the coil ends where they rub on the coil buckets. The wire diameter should be measured on every coil wrap and then averaged, as the diameter can vary by up to 0.5mm across all coil wraps. Note my measurements now exclude the powder coat.
120/Hilux/150/FJ coils;
Landcruiser coils;
The second figure for OEM coil spring rate has been determined by load testing at King Springs. Here is a video showing how Dobinsons manufacture their coils, you can see the load testing performed at the 4:20 mark, where the coil is fully 100% compressed to solid coil height;
https://www.youtube.com/watch?v=en8Q...&nohtml5=False
Many thanks to John at Zordos Suspension for providing OEM coils for measurements, and to Steve at King Springs for load deflection testing of 12 coils.
If anyone has their pre 2015 OEM 150 petrol coils, if you’re willing to donate them to my coil collection could you PM me so I can complete the table. I’d also like to get some earlier Hilux coils from 05/06, as I suspect they have changed free height and spring rate slightly up to the 2015 coils I have measured. Same applies for Landcruiser coils, if you have some, please let me know!
This is a work in progress, so I’ll update the table every time I get some new data.
Best
Mark
Comment