My Yellow Speed Racing Review
Fitted my YSRs on the Mazda MX5 ND. I havent found any reviews on this product when i was looking to make my purchase, so im hoping someone will find this useful in the future (hello mystery web browsing person! 
)
The Spring rates are the 7kg/4kg variant and 33-way adjustable shocks.
Highlight items to prepare for:
- Ride height dropped by 20mm within a few hundred miles of driving. be prepare to re-adjust
- Must ensure you buy the headlight leveling tool OR perform the OBD2 reset option (if you are brave).
- the rears come with extended adjustment ‘rods’ for the shocks, so you can adjust directly from the boot.
- the fronts will fit under the stock OEM strut bar, but you will need to remove to adjust on the fly. best buy an aftermarket one for regular tuning or adjustment accessibility.
- The first couple of miles from the garage these springs feel like concrete! do not panic. read below, they soon got softer and flexed into their desired position.
I fitted these coilovers the same time as the Eibach ARBs / anti roll bars. I’m very happy with how they feel. Ive had various coilover setps on previous cars and i always look for a setup thats stiffer than any road car you will come across, but will happily skip along a back country lane without feeling i am bending the chasis.
This YSR meets that. Despite the huge spring rate increase from OEM
(in KG, the OEM is approx 2.7kg/1.4KG vs the 7kg/4kg). Bear in mind there are track specific spring rates, and they are much much stiffer again, clearing the 10kg mark on most.
The addition of the arbs also ensure that the car is very very flat on the bends.
The inital ride height (floor to pinch weld, the correct measurement!)
Front / Rear
OEM 145mm / 150mm
YSR initial fitment 115mm / 118mm
YSR after settling 95mm / 100mm
YSR after readjusting (now stable) 120mm / 128mm
I had arch rubbing at that settle-level on the front. rears had loads of space at the top and the sides.
When i readjusted i added some more heigh back in, and increased the rake angle.
To give rough guidance, i am at the level you would expect to be with your typical lowering springs for eibach/progress etc.
Shocks
In terms of the inital tuning of the shocks(once the Geo was complete - i used 949’s ‘‘Dual purpose geo’’) i had the shocks tuned to the following, to help give some initial guidance: (again, i couldnt find anything online about this from other peoples experience)
there are 33 clicks on the shocks for stiffness. All measurements are taken from the ‘most stiff’ (so, 1 is the softest, 33 is the stiffest. ‘‘10 clicks’’ would be 23/33)
I set front and rears to be 10 clicks on initial install. I found that this was fine for A roads for comfort and traction, however on any sort of B or C road the bound-rate was too slow meaning the rear tyres werent able to keep contact patch when hard accelerating which resulting in feeling like a flat stone across a lake.
Only adjusting the rears, i took that down to 28 clicks. this fixed the traction on bumps, but immediately introduced alot of body roll back into the ride (at the rear).
After playing around with it i have come in at 15 clicks which seems to be the sweet spot of minimal body roll, max traction over bumps (for everyday use). for track i would be heading towards the stiffest of course 
For the fronts, i came to adjust these AFTER the rears. (so, rears are at 15 clicks now before i touched the front)
The springs here are much stiffer, but they also have to handle the bulk of the cars mass. i took these down to 28 clicks, and found this to be a huge grip improvement on the B and C roads over 10 clicks. After some fine tuning i am settled with 24 clicks at the front.
so summary:
24 clicks front
15 clicks rear
This has given me a compliant car on A roads with a much improved experience vs OEM. and on the B and C roads (where i spend most of my time… i live in scotland!) it allows me to get the power down and keep it down on bumpy corners.
*final comment - these settings i now have are specific to the following conditions: ‘‘primarily throwing around corners on back country lanes where the road is not flat or smooth’’.
If you spend most of your driving near roundabouts, A roads and motoway i would personally suggest starting at 10 clicks front and rear too, as this will be a closer ballpark for what you will be wanting. and gives scope still to be stiffer on track when needed.
I cant wait to get it to track next season
