Lowered and axles

[tofurun]

I have read in a few places where lowering the car weakens the rear axles. I am about to start my suspension build and need to know a safe distance I can lower the car without worrying about hurting the rear axles. Something about the angle from being lower makes them weaker. I am also making double the stock cars hp so that's a factor too, the last thing I need is to stress them more. Anyone very knowledgeable on this specifically?

[gramicci101]

Going lower than about an inch stresses the cv joint. The stance crowd has parts specifically to raise the subframe and bring the axles back to a somewhat normal angle. That said, plenty of people run 1-1.5 inches down with no issues.

[churchx]

It's more about angle of connection of axle with diff. If one goes overboard with lowering, worth installing some diff riser for angle to get shallower, to lessen load of work joint has to do per each turn.
Also, it's not just about rear .. if one cares also about handling, worth searching about roll center adjusting to fix some handling issues overlowering introduces.
And stiffer suspension.
And ..

BUT! That all is not much of an issue .. if one lowers at reasonable extent, eg. <1". Also you'll keep this way more practicality/compliance/drivability/comfort for daily driving. (for example, worth installing much stiffer springs to compensate overlowered suspension bumpless travel. So for not going overboard your spine will thank you for not making car undriveably harsh).

[DAEMANO]

@tofurun

I've covered this in quite a few posts.

-1.2" or less = generally safe
-1.5" = rolling the dice
-1.6" or more = trouble, especially if running improved power.

PartsShopMax has what you need for $100. Install likely needs a professional.
https://store.partsshopmax.com/shop/...s/ZNC6SDR.html

FRS / BRZ Solid Diff Riser

The axle angle is so bad when this car is lowered that it puts a lot of strain on the axle joints. This bushing set eases the angle of the axles on lowered cars by raising the diff 20mm. Bolt on CNC aluminum gold anodized front bushings and Weld on laser cut steel subframe/rear diff mounts with new hardware. The FRS and BRZ use a lexus diff and also the luxury oil filled rubber mounts that are great for canceling a lot of noise, vibration, and harshness from the luxury car but they are doing you a disservice getting the power to the ground in your sports car. CLICK HERE to jump to the forum to see our installation example.

[wparsons]

It also depends on how much camber you're running, more camber in the rear increases the angle the outer CV joint has to work through.

[smg1138]

Originally Posted by wparsons

It also depends on how much camber you're running, more camber in the rear increases the angle the outer CV joint has to work through.

How much negative camber can damage the CV joint? I generally run about -2 in the rear.

[JDM4E]

Does anybody do diff risers that are "the same" or similar like OEM in terms of NVH? I would like to do +20mm but OEM style.

[wparsons]

Originally Posted by smg1138

How much negative camber can damage the CV joint? I generally run about -2 in the rear.

It'll depend on ride height as well. What ultimately does the damage is the angle the CV joint is working at. Being lower increases it, but so does camber.

[DAEMANO]

Originally Posted by JDM4E

Does anybody do diff risers that are "the same" or similar like OEM in terms of NVH? I would like to do +20mm but OEM style.

I know there is another company making them (Whiteline I think or perhaps or Cusco) unsure if they're soft or solid.

[J95]

Originally Posted by DAEMANO

@tofurun

I've covered this in quite a few posts.

-1.2" or less = generally safe
-1.5" = rolling the dice
-1.6" or more = trouble, especially if running improved power.

PartsShopMax has what you need for $100. Install likely needs a professional.
https://store.partsshopmax.com/shop/...s/ZNC6SDR.html

Is there any updated info about this? Lately I am reading a lot about people breaking axles but I am unsure about the amount of drop that causes it

I plan on lowering aorund 1,2-1,5 inch so maybe at the limit. I want to track the car often (NA) and I wonder if do I really need the risers

Originally Posted by DAEMANO

I know there is another company making them (Whiteline I think or perhaps or Cusco) unsure if they're soft or solid.

can you tell if you mean this one?
https://www.cspracing.com/whiteline-...ing/wl-kdt924/


I presume you can raise the diff because there are 3 holes but not sure. PSM kit has other parts too

[NoHaveMSG]

Originally Posted by J95

Is there any updated info about this? Lately I am reading a lot about people breaking axles but I am unsure about the amount of drop that causes it

I plan on lowering aorund 1,2-1,5 inch so maybe at the limit. I want to track the car often (NA) and I wonder if do I really need the risers





can you tell if you mean this one?
https://www.cspracing.com/whiteline-...ing/wl-kdt924/


I presume you can raise the diff because there are 3 holes but not sure. PSM kit has other parts too

I have been running around -1.5 on my car for a long time, FBO with flex fuel, tons of track days, no CV issues.

Also keep in mind raising the subframe height increases anti squat which will have a negative effect on putting down power. We already have too much anti squat in the rear suspension geometry. SPL documents this in their installation instructions.

https://www.splparts.com/products/fr...-bushings.html

[J95]

Originally Posted by NoHaveMSG

I have been running around -1.5 on my car for a long time, FBO with flex fuel, tons of track days, no CV issues.

Also keep in mind raising the subframe height increases anti squat which will have a negative effect on putting down power. We already have too much anti squat in the rear suspension geometry. SPL documents this in their installation instructions.

https://www.splparts.com/products/fr...-bushings.html

that sounds good, thanks for sharing the experience
it would be so helpful if those who did have CV issues can share their ride height

about anti squat, I had no idea about that... good to know! however I would only raise the differential, so I believe it should remain the same

edit: well I just found this post... will be super helpful
https://www.ft86club.com/forums/showthread.php?t=49511

[NoHaveMSG]

Originally Posted by J95

however I would only raise the differential, so I believe it should remain the same

If you could that would be great. You may need to have some custom solid rear bushings for the diff to do it. Really going to have to measure the pinion angles and see what is possible.

[J95]

Originally Posted by NoHaveMSG

If you could that would be great. You may need to have some custom solid rear bushings for the diff to do it. Really going to have to measure the pinion angles and see what is possible.

its possible with these parts
https://store.partsshopmax.com/ZNC6SDR.html