Overview of Ride Harmonizer concept - Front Roll Couple (FRC) - Keeping a car's handling neutral

#FatCatMotorsports #FCMElite #RideHarmony #FlatRide #Mazda #Miata #NB #suspension #tuning #SuspensionTruth #swaybars #handling
Short overview of the concept of Front Roll Couple which is a measure of how understeer or oversteer-biased your suspension is.
You can view the various NA and NB Mazda Miata Ride Harmony spreadsheets here. In this live stream, I go over the way I select springs, sway bars, and bump stops for:
1. Stock springs (regular street and E Street autocross)
2. 'Touring/Comfort' FCM Elite coilovers
3. 'GT/High Performance' FCM Elite coilovers
4. 'Track/Race' FCM Elite coilovers
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For a 1 on 1 FCM Elite consult (30 min for $125), use this link to send in your consult form and payment via Paypal:
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[@sr20dett1000]

Just got Bilstein B8 for my E90 with tein lowering springs. Those are one of the few lowering springs that give springs rates 191lbs front and 593lbs rear giving me 8-9% flat ride. That's already 36% stiffer in front and 29% stiffer in the rear. Thank for all for information and educational videos. It's seems tein does a good job with springs rates that maintain flat ride even on E46. I think the spring rates are to low, will see how much I drop.

[@SuspensionTruth]

Glad you appreciate the information, always good to engage. What you may not realize is that the steel springs are about half of the total ACTUAL spring rate - the bump stops provide about 150-200 lb/in once they start to engage (the front in particular, the rear less). If you're lowering and planning to change bump stops, that's a BAD IDEA, IMO. You are going to have very limited travel and not enough total spring rate to absorb bigger hits. That will stress the rest of the suspension. To properly lower the car without screwing up the ride or being into the bump stops all the time you need to have spring rates in the 350+ range up front, and the rear being inboard mounted you can't do a straight percentage, you have to look at the WHEEL RATE including the motion ratio. Don't think you know what you're doing just throwing numbers off a forum and saying "yeah, I can run this and be fine!" If someone has done the same thing and reports good results then maybe you're okay. I have a local E92 M3 customer who has this to say about changing from OE to Bilstein B6: "I'm not talented enough to say the B6s were any better on track than the stock EDCs. I'd judge them to be acceptable on track, but I still find the street behavior unacceptable." Lowering springs also are notorious for sagging. I would HIGHLY recommend you leave the front bump stop alone - just because you see a video doesn't mean you have to, or SHOULD make a mod. I changed bump stops because I IMPROVED the damping to remove the jacking down that makes the Bilsteins 'unacceptable' as my upcoming E92 M3 customer said. If you shortened the bump stops with a stock Bilstein B8 (likely even stiffer than the B6 / HD) PLUS throw on lowering springs then you are likely in for a world of hurt. The damping makes the BIGGEST difference in how a car behaves. Springs and bump stops and sway bars are important, but it's what very few people see or understand that affects the most.

[@sr20dett1000]

@@SuspensionTruth I have a stock e90 with non sport suspension. The struts and shocks are worn out or blown. Even with the worn out suspension I think the e90 on stock suspension handles well on the canyon roads. I don't push it to the limit because I'm on the street. I believe my E90 handles better than my E46 on stock sport suspension.

[@sr20dett1000]

@@SuspensionTruth forgot to address bump stop modification. I didn't say I would modify bumps stops. Is it because most lowering springs require in their instructions to modify bumps.