Anyone have suggestions on spring rates? ill be dropping my car on BC coilovers about 3-4 inches not slammed but low. Im thinking 16k front/14k rear, on stock rims, don't want to bottom out, stiff ride is fine with me as I've grown up around import racers/slammed trucks back in Hawaii. Ive done some searching and most people do the complete opposite spring rates i.e. 14k front/16k rear
BC coilovers spring rates
- Thread starter FX808702
- Start date
- Car
- 2017 QX70S
- Name
- Andy
14K/16K will be too stiff for me for sure. Its personal preference, there's no right or wrong. With properly adjusted dampening, you won't bottom out with 12K front & rear.
Given the added weight of the V8 block of the FX45, I'm have 12K front. I used to have a FX35 and I also have 12K front o it; it rides not as nice as the FX45 with 12K front.
Not sure if there is that much weight difference between the 1st & 2nd Gen, but its good info for your thought.
Given the added weight of the V8 block of the FX45, I'm have 12K front. I used to have a FX35 and I also have 12K front o it; it rides not as nice as the FX45 with 12K front.
Not sure if there is that much weight difference between the 1st & 2nd Gen, but its good info for your thought.
The reason people run higher rear spring rates and why coilovers are built with higher spring rates in rear is that the suspension design is different. On a first gen, the front is a mac strut which means the spring is very close to the wheels. The rear is a multilink and you'll see the spring is further inboard. The closer the spring is to the wheel, the lower the rate can be since there is less leverage. That's why on 1st gens the front spring rate is always lower than the rear even though the front is heavier. This is the case with most cars - the front springs are further out. I currently run 12K/14K because at the time BC didn't make any higher rates. Honestly if I could do it again, I'd run a stiffer spring in the rear. To me, the 12K is too stiff in front relative to the 14K in the rear so there is a porpoising over big bumps - front doesn't compress nearly as much as the rear. I only went 12K in front because of my ride height as I was tired of bottoming out. I forget, but I read an article on spring rates that basically recommended almost double the rear rate as the front for proper balance on a mac strut front / rear multilink suspension. This was for race cars but the theory is valid. If I could get 18K or 20K on mine I would have done that with the 12K in front.
Your 2nd gen runs a double wishbone front so the leverage is going to be different than the 1st gen. I don't know if it will be significantly different, but it will be different. I think I can safely say that it's not going to be different enough that you would run a higher spring rate in front than the rear.
Your best option is to call BC and get their opinion or Swift or anyone who makes replacement springs. No one on the forum designs suspensions so it's much better to go to the source.
Your 2nd gen runs a double wishbone front so the leverage is going to be different than the 1st gen. I don't know if it will be significantly different, but it will be different. I think I can safely say that it's not going to be different enough that you would run a higher spring rate in front than the rear.
Your best option is to call BC and get their opinion or Swift or anyone who makes replacement springs. No one on the forum designs suspensions so it's much better to go to the source.
The answer I was looking for! Thanks!! I decided to go 12k front and 16k rear, but I'll ask BC what they would recommend. Thanks again for the advice and knowledge!