Suspension Help

[FLtrackdays]

@FLtrackdays - I'm thinking of having my local shop do the rear bar as well but it sounds like they haven't done one in the a90 yet. I thought I read somewhere about a couple single use bolts on the rear subframe. Did your mechanic mention anything like this or run into any issues during reinstall? I haven't heard of anything like this before but this is my first BMW

Welcome to the club! My mechanic pretended like it was no sweat . At least that was my perception and he didn’t say anything. I would definitely do as Fuzzy says. His advice has been mega solid across this forum. My 2 cents. And they added some new bolts as well.

Sponsored

 

[DarkZupra]

@DarkZupra You never specified where you are rubbing. Also, what camber are you running? Lastly, how low is your car? I run RT660s which run wide in their 315 wide flavor and mine dont rub anywhere.

I was rubbing on the outside of the tire against the fender. You cant really compare tire size to tire size without including wheel width and offset. I think mine was JUST close enough that, because my suspension is on the softer side, i was rubbing on bumps. the 295s have fixed that for me about 95%. Ill eventually do the full SPL armset, but im not doing that myself.

 

[FLtrackdays]

I was rubbing on the outside of the tire against the fender. You cant really compare tire size to tire size without including wheel width and offset. I think mine was JUST close enough that, because my suspension is on the softer side, i was rubbing on bumps. the 295s have fixed that for me about 95%. Ill eventually do the full SPL armset, but im not doing that myself.

When I read @Evolution question, I was thinking “is he talking to me?”. I didn’t realize this exact same thing happened to you too . Sorry to hear but you make me feel better. If that’s any constellation. He recommended Ohlins on another thread and I bought them. Feels much stiffer. And I’m no longer slammed to the ground. I have the SPL bits. Giving her a go this weekend. Feeling mega confident I won’t blow a tire this time

 

[DarkZupra]

I dont hate my KW DDCs. Theyre a great dual use coil. They are a touch soft for me, but soft isnt necessarily bad. Too stiff of suspension reduces tire grip. I may see if i can get slightly stiffer springs for them, otherwise I may go Ohlins, but I do love that these keep the active setup from OEM. Gives a great ride in comfort, and is just stiff enough in sport.

 

[Rob901]

Welcome to the club! My mechanic pretended like it was no sweat . At least that was my perception and he didn’t say anything. I would definitely do as Fuzzy says. His advice has been mega solid across this forum. My 2 cents

Just got a quote for all the bolts/nuts. $80 for some peace of mind seems worth it.

 

[Evolution]

I was rubbing on the outside of the tire against the fender. You cant really compare tire size to tire size without including wheel width and offset. I think mine was JUST close enough that, because my suspension is on the softer side, i was rubbing on bumps. the 295s have fixed that for me about 95%. Ill eventually do the full SPL armset, but im not doing that myself.

I can completely compare tire size since my wheel setup is nearly identical to yours. We are within 2mm of each other for offset and my width is the same. You never answered how low you are or what your camber is. Those 2 are going to play a big part in why you are rubbing. I am going to guess you have very little camber and that is going to be why you are rubbing with such a small tire. Even though you dont have all the SPL stuff, you can dial in some good camber.

 

[DarkZupra]

I can completely compare tire size since my wheel setup is nearly identical to yours. We are within 2mm of each other for offset and my width is the same. You never answered how low you are or what your camber is. Those 2 are going to play a big part in why you are rubbing. I am going to guess you have very little camber and that is going to be why you are rubbing with such a small tire. Even though you dont have all the SPL stuff, you can dial in some good camber.

Rear camber is -2.5, i dont typically measure how far i lower a car, I do it until it looks and feels right. Plenty of pics to reference in my build thread, but im not dumped.

 

[Evolution]

Rear camber is -2.5, i dont typically measure how far i lower a car, I do it until it looks and feels right. Plenty of pics to reference in my build thread, but im not dumped.

Camber isnt bad but setting it at 2.7-2.8° would definitely help. Your wheel offset is honestly just a hair too much. If you were closer to a 40 offset, that would solve your issue since you still have some room on the inside of the wheel.

 

[DarkZupra]

Camber isnt bad but setting it at 2.7-2.8° would definitely help. Your wheel offset is honestly just a hair too much. If you were closer to a 40 offset, that would solve your issue since you still have some room on the inside of the wheel.

Yep im aware of that. However the 295 width tire fixed it, so Im fine.

 

[decodeddiesel]

There are some, the Cusco rear sway install doc has the OEM part numbers for the single use bolts if you want to replace them.

https://assets.ctfassets.net/fmj32k...22_rear_sway_bar_2020_toyota_gr_supra_a90.pdf

Omg! Thank you for posting the instructions in English!! Everything I got with the anti-roll bar was in Japanese with grainy black and white pictures.

I think I can do this with my buddy once I get my Quickjacks.

 

[suicidaleggroll]

Omg! Thank you for posting the instructions in English!! Everything I got with the anti-roll bar was in Japanese with grainy black and white pictures.

I think I can do this with my buddy once I get my Quickjacks.

Yeah it's really not that difficult, just time consuming. I did it by myself in 2 days, but I was also installing all of the SPL arms and a few other things at the same time. If I was just doing the rear sway I definitely could have done it in a day.

 

[decodeddiesel]

Just got a quote for all the bolts/nuts. $80 for some peace of mind seems worth it.

Are you going through a dealership for these parts or do you have a source online?

 

[decodeddiesel]

Yeah it's really not that difficult, just time consuming. I did it by myself in 2 days, but I was also installing all of the SPL arms and a few other things at the same time. If I was just doing the rear sway I definitely could have done it in a day.

Aw man, that's good news. BTW your write up on the SPL arms is outstanding and very motivating.

I'm still trying to find a shop within 50 miles of me that's willing to do an alignment on my car once I put the SPL bits on. That is something I really miss about living in Denver. I had like 5 shops within 10 miles of my house that would do it without a second thought.

 

[FLtrackdays]

Aw man, that's good news. BTW your write up on the SPL arms is outstanding and very motivating.

I'm still trying to find a shop within 50 miles of me that's willing to do an alignment on my car once I put the SPL bits on. That is something I really miss about living in Denver. I had like 5 shops within 10 miles of my house that would do it without a second thought.

Way smarter than me (like most on this forum). I went to Toyota, big mistake. BMW, they did it but…. I finally found 2 shops that actually did track alignments w/ SPL parts. Worth the 30-40 min drive.

Camber isnt bad but setting it at 2.7-2.8° would definitely help. Your wheel offset is honestly just a hair too much. If you were closer to a 40 offset, that would solve your issue since you still have some room on the inside of the wheel.

I’ll have to try this next time. Not the same tire setup as you guys, being square, but I’ve tried -2.5 and -3.0 all around. I didn’t notice a huge difference. So, back to -2.5, for now.

 

[Rob901]

Are you going through a dealership for these parts or do you have a source online?

Just a local dealership

Sponsored