Advice on springs to pair with Bilstein dampers

[ayoustin]

I have Bilstein HD shocks on my N54 135i with stock springs. I can measure ride height (fender to wheel center) tomorrow, if needed.

[850tgul]

I'll jump in with the stats on my 128. Bilstein HD, swift spec r springs, Dinan camber plates in front, Dinan rear shock mount kit. All on 18x8.5 et45 Apex Arc-8s with Hankook 235/40/18 tires all around. I'm about 1 month on this setup so could still be settling I suppose.

I measured two ways here; ground to fender and center of the wheel to fender (on BMW center caps I used the intersecting lines of the BMW logo).

Driver Side Front :
13 & 5/16ths center to fender
25 & 5/16ths ground to fender

Driver Side Rear:
13 & 4/16ths center to fender
25 & 4/16ths ground to fender

Pax Side Front :
13 & 2/16ths center to fender
25 & 2/16ths ground to fender

Pax Side Rear:
13 & 1/16ths center to fender
25 & 1/16ths ground to fender

[houtan]

Had a chance to measure my front and rear. I only did from Ground to fender.

Driver and Passenger Front = 24 1/2
Driver and Passenger Rear = 24 7/8

So my front is sitting lower by about 3/8 of an inch.

[NIB]

Originally Posted by 850tgul

Should clarify that I have already decided to go with Bilstein B6/HD dampers. Went with these because they can be used with every spring from oem sport to Eibach, BMWP, or Swift. If I went with the B8/Sport dampers I'd have to use one of the lower springs. thx

1 have 225/45R18 wheel and tyre set up on the four corners of mine car, 2009 base model 128i Convertible, and the front passenger side (Right) is rubbing on the Strut and hooking. if I switch the wheel with the rear right passenger wheel, it stops hooking and roll. I want to change the tyre settings to 225/40R18 on all four sides. Mine question is, will the rubbing and hooking stop and if not what struts and springs should i install so as to forestall the hooking and rubbing with the struts for this tyre usage.

[850tgul]

What size wheels are u using, width and offsets?

[NIB]

Originally Posted by 850tgul

What size wheels are u using, width and offsets?

Wheel size I use is 81/2J X 18ET.52 with an offset of +51mm. I still want to maintain the wheel because it is factory fitted, advice if 225/40R18 Tires for all four corners will work or if another tire specs.

[ShocknAwe]

Originally Posted by NIB

Wheel size I use is 81/2J X 18ET.52 with an offset of +51mm. I still want to maintain the wheel because it is factory fitted, advice if 225/40R18 Tires for all four corners will work or if another tire specs.

For those widths and 18" diameter you should be using 40 profile tire in the front, and 35 profile tire in the rear. 45 profile possibly coupled with the 52 offset may be causing your problem. Too tall and rubbing on the spring perch. 45 offset is ideal for the stock front on these cars.

[NIB]

Originally Posted by ShocknAwe

For those widths and 18" diameter you should be using 40 profile tire in the front, and 35 profile tire in the rear. 45 profile possibly coupled with the 52 offset may be causing your problem. Too tall and rubbing on the spring perch. 45 offset is ideal for the stock front on these cars.

I can only get a BMW Rim of 8J/R18 with an offset of +30mm. Will this work for both front and rear wheel or should I attach a spacer of 10mm to bring it up to +40mm for both rear and front. My fear is the quality of work for the attachment by our local technicians.

Will 225/40R18 tyres not work for both front and rear wheel.

[ShocknAwe]

Originally Posted by NIB

I can only get a BMW Rim of 8J/R18 with an offset of +30mm. Will this work for both front and rear wheel or should I attach a spacer of 10mm to bring it up to +40mm for both rear and front. My fear is the quality of work for the attachment by our local technicians.

Will 225/40R18 tyres not work for both front and rear wheel.

Adding a spacer will make it worse. +30 offset with a 10mm spacer will make the new offset effectively +20.

225 square will work fine for an 8" wheel front and rear.

[NIB]

Originally Posted by ShocknAwe

Adding a spacer will make it worse. +30 offset with a 10mm spacer will make the new offset effectively +20.

225 square will work fine for an 8" wheel front and rear.

So you advise I should use the 8J/R18 offset +30mm

[ShocknAwe]

Originally Posted by NIB

So you advise I should use the 8J/R18 offset +30mm

If that's your only option.