Questions about coil springs: length, preload, and spring rate

So I just installed some new coilovers (FOX FTS2100) and the ride is very rough. Every time I hit a pot hole it feels unbelievably harsh. I noticed it doesn't flex at all on larger obstacles either which makes going over ruts and rocks unbearable.

Right now I have the preload set pretty high but not out of spec. I tried to match the front to the rear and I have done a pretty good job of that so keeping the current height would be ideal.

So my question is if I wanted to soften the front and keep the lift I have, what would need to happen? Should I buy longer springs with the same rate or higher spring rate ones? They are used and I rebuilt the shock but I didn't get new springs. Who knows how many miles are on the old ones. I believe the springs that come with them are originally 13" and 650lbs. Would say a 14" 600 lb one be softer? Or a 14" 700lb one?

Thanks!

 

The spring rate tells you how many pounds it takes to compress the spring 1 inch. So, the higher the number the stiffer the ride.

I personally tried 600, 650 and 700. Now, I only run 600 and would run 580 if available.

To answer your original question. You want longer springs with a lower rate. You can always crank them up for lift but you cannot lessen the rate.

 

Thank you! So I should try to get a longer spring with the lowest rate? Doing so will still allow the truck to be lifted the same amount?

 

650lb springs are way too heavy for a first gen with no front end weight, you'll want a plate bumper + winch and skids for those springs to feel better. The preload for lift isn't helping either.

I have 600# on my Kings with just a steel skid plate and they are pretty stiff

 

I watch people debate this all the time. Ride is a preference. I want a smooth ride and long travel. I find the lowest spring rate available. I don't care if the nose dives on a hard stop. I am not driving a sports car. I want a suspension that moves and won't beat you to death going over the bumps.

 

Interesting. I knew these trucks were pretty light but no that light. In the next few weeks I will be purchasing an All-Pro baja style front bumper. Do you think this would be enough weight or should I still look for some 600lb springs?

 

I'm by no means an expert on this stuff as the whole spring length vs. rating vs. preload vs. valving equation makes my head spin. All I know is that my Kings with 600# springs adjusted for ~2.25" lift are pretty darn stiff, too. I do know eventually I'm going to be adding a heavier bumper so I don't want to go with lighter springs, but it was suggested to me that I get my Kings revalved for a softer ride so that's what I plan on doing when the time comes to rebuild them.

 

This is exactly what I am thinking. Thanks!

 

I still think they might be too heavy for that but honestly I can't say for sure. Keep in mind our 1st gens came stock with < 500lb springs so 650 is pretty heavy duty for them.

 

Related, but shock pressure plays a role in coil rate as well. Let's say you want a 675 lb coil but only have 650 or 700 as options. You could go 650 and pump a little more gas in there, or visa versa. There's only so much adjustibility with that, but it is there. So I'd get 14" in whatever rate you determine you need, and a local shop could help you out with the gas if it comes to that.

 

On paper this sounds good but in my experience I disagree. I know I'm a second gen but the concept applies. I had 590lb coils, added a lot of weight, and then went to 660 lb coils. God damn the thing rode so much better with the stiffer coils, because they were a better pair for the weight I had up front.

 

I get that, valving is a whole different beast that's for sure. I'll get some 14" 600lb springs and see how they feel.

I didn't know that stock was only 500lb. 600lb is a large jump compared to stock.

 

I have mine filled to the recommended 200psi. I'm no expert on shocks at all and just followed the directions while rebuilding.

 

yeah for example the OME (old man emu) springs for 1st gens are all 500lb springs (OME 880 - 882) and the heavier ones for added weight are 590lb. They don't even advertise a spring above 600lbs for our trucks, you'd have to get one of the 2nd gen Tacoma springs to get a 650lb one

 

How much weight do you have added?

 

Nothing wrong with that at all, I have no idea what my fronts are at and have my rear at 150psi. Just wanted to let you know that you have some adjustability there. Before you go start messing with pressure though, I'd ask fox what the range is you should be within.

I went from a stock front end to an extra 265 lbs (bumper+winch+IFS skid). The thing nose dove like a mofo. For reference, stock for 2nd gens is 500 I believe, I had 590, and went to 660.

I don't know too much about 1st gens but it does sound like 14" 600 will be a good choice for you.

 

Good to know! In that case I would probably benefit greatly downsizing to a 600lb spring. And if OME's springs are rated at 590 for extra weight I'm sure adding a bumper/winch with 600lb springs would even out pretty good.

 

I know some 1st gen guys go with heavier ones (even know one here that does 700lb springs) but they are running a lot of added weight

 

I would definitely play around with pressures if the shops around me didn't charge $30 per shock to refill. I know on my bike lower pressure makes a huge difference (granted they are air shox) but id imagine the pressure makes a difference on coilovers too. I'll give Fox a call and see what they say.

That's quite a bit of weight but I think it was well worth it. Your truck looks super nice! I don't think ill be adding that much weight so year a 600 14" would probably be perfect. I also think 1st gens weigh less in the front due to the smaller engine.

 

Worst case if I end up adding too much weight I can always install some heavier springs. For now though 650 is way too much for me. That's crazy that people have enough weight to warrant 700lb springs.