Clubsports have arrived, finally...

[MoonieGT]

After a two month wait they have arrived Won't get to install them until next weekend...

Coilover.JPG

[wrx74]

What springs will you install with these?

[MoonieGT]

550/350 with helper springs. They're being shipped from 949 Racing and won't be here till Tuesday...

[wrx74]

550/350 with helper springs. They're being shipped from 949 racing and won't be here till tuesday...

= skateboard!

[SirHustlerEsq]

Welcome to the skateboard crew.

[MoonieGT]

The ridiculousness of my wait takes another turn. In a Murphy's-law twist, I had bought a necklace online for my wife. The necklace was damaged upon receipt and needed to go back for an exchange. The company arranged for FedEx to come to my house and pick up the necklace. Here's the bad part. My springs were shipped separate from the shocks and arrived yesterday, but no one was home to receive them so FedEx left them on the front porch. Do you see where this is going? FedEx then showed up again later to pick up the necklace, saw a box sitting on the front porch, and took it! They took my springs @#!Q#@ which are the last piece of the coilover puzzle that I've been trying to solve for 2.5 months! I called FedEx yesterday and they said that they would call the distribution center and get back to me. I was NOT happy yesterday (that is until I got to go to Game 4 last night for Mavs series tying win!!!!) As of this morning they had not gotten back to me so I called them again. This time with better results. My springs should be re-delivered to me tomorrow... Maybe someday I'll get to install my coilovers... so what else will go wrong...

[SirHustlerEsq]

lol, that sucks.

[jeff_man]

Fedex says no skateboard for you. think i need some softer spring, the 800/550 hurt by back.

[MoonieGT]

Fedex says no skateboard for you. think i need some softer spring, the 800/550 hurt by back.

Are you running slicks? If not, you probably don't want those rates any way... I was told when I ordered mine that a car will make more grip if it's slightly under sprung copare to a car that is over sprung. I'm currently only on S-Drives, but I'm going to go to an AD08 or Starspec etc. next. For that tire I was told 550/350 was about as high as I should go. I asked about using 600 fronts and was told not to on the tires I plan on running.

[jeff_man]

Are you running slicks? If not, you probably don't want those rates any way... I was told when I ordered mine that a car will make more grip if it's slightly under sprung copare to a car that is over sprung. I'm currently only on S-Drives, but I'm going to go to an AD08 or Starspec etc. next. For that tire I was told 550/350 was about as high as I should go. I asked about using 600 fronts and was told not to on the tires I plan on running.

car is glue running 225/45/15 nt01.

[sean]

Spring rate choices on a miata are predicated on two things 1) grip provided by the tire and 2) lowered ride height (which coincidentally increases available grip). You have only considered the first. Many miatas with street tires run grater than 550 rates becasue they run sub 12 inch ride heights.

I get ~1 inch compression at the wheel in roll at 1.2g's per my data. With 550s, the back of the envelope says i would compress the shock another another .2 inches. Thus to the extent a car could ride at 12 inch ride heights on 550s, a car could run at 11.8 on 700s and still retain the same remaining travel and that remaining travel would go further.

Because CG is so important to autoxers, it often makes sense to run much higher rates in order to get lower CG.

[MoonieGT]

^ Good points. It was explained to me that if you run rates that are too high for your tire you will achieve less grip from the tire than it is capable of. Put another way, (and I'm just making up numbers for an example) if you over spring a tire you might get 90% of the total grip level the tire would otherwise be capable of but for the over-springing. Something about at the limit, the too-stiff spring will cause the tire to skip/shudder across the pavement.

I'm not an expert and I don't know what's right. But I trust the person the info came from, YMMV.

[jeff_man]

i r dumb, i just let ast pick my rates. car is ~4" f 4.25" r at the pinch seems. i could go lower and the higher rate keep the tires from rubbing but it's makes it harder to jack up and get over bumps so i said fuck it, i can deal with losing some tenths to make life easier.

[modernbeat]

Running 205 Star Specs on 700F/450R as a daily driver. The ride is comfortable at those rates with a decent shock to back them up. Both AJ and Matt at Vorshlag have commented on the comfortable ride.

[sean]

^ Good points. It was explained to me that if you run rates that are too high for your tire you will achieve less grip from the tire than it is capable of.

A few things

On a smooth surface with the exact same roll-couple--and all other things else equal--spring rates have no effect on the grip of a tire. Geometry excluded and with identical weight distribution and roll couple - ultimate grip is governed by two things: CG and Track (see http://www.rhoadescamaro.com/build/?page_id=764)

Practically, spring rates effect geometry and therefore grip, less so with a car like the miata that has good camber curves. Rough surfaces also can theoretically--when rates get absurd--cause reduced grip. But IMO, with high end shocks with good highspeed blowoff, this is not much of a problem with sane rates.

I think most people's impression that a car is oversprung derives from two sources (only one is really based on the spring rate):
1) cheap shocks that don't have effective highspeed blowoff or low speed damping
2) Increased rate of weight transfer from higher spring rates. This is where the tire type matters, Rcomps are much more transition tolerant that street tires (i.e. as long as you stay below their maximum grip, they can load up as quickly as you want), Street tires require a little slower ramp up to full grip, so as rates go up turn in needs to be smoother.

This is all abstract - individual vehicles, geometry, tires, wheels etc can have significant effects. Bottom line, because the miata is a great platform, most front rates between 500 and 800 can be made to work well at some reasonable height, with a big bar. I bet higher rates could work with a smaller front bar, but no one has really messed with it. I remember hearing some west-coast STS'ers were trying it, but I'm not sure what has become of that. Modernbeat might know more about that.

[MoonieGT]

That's good info, thanks Sean.

[MoonieGT]

Install question: I'm reusing my top hats. I've seen people say that it's possible to disassemble the shock while it's being taken off the car so that you don't have to use a spring compressor? Is that right? Is it a good idea? And if so, any good tips on doing so?

[jeff_man]

if you undo the top hat while the shock is on the car it will be so much harder to get the stock shocks off the car i believe. You can zip the top hat bolt of the stock shock and just have the hold thing explode apart. just do it somewhere that the shock can't take off one way under the load on the spring.

[sammm]

any good tips

Do yourself (and your body parts) a favor and remove the entire shock assembly still intact. Compress the springs (with a spring compressor) and then remove the top hat.

[BigDmiata]

Doing my vmaxx, I didn't bother with a spring compressor. Once off my car, I just took it over to the side of my house and stepped on the coil and part of the top hat while I unbolted it. Parts didn't shoot off but a few inches.