I am installing BC coilovers on a 03 MCS and the front wheels seem awfully close to the lower ring on the coilovers. Do I need wheel spacers and if so what is a good recommended size?

 

It all depends on your wheel width, offset, tire size and shape. There will not be a universal answer.

I'm sure some will think my recommendation isn't conservative enough, however if my tires will clear the struts without compressing two sheets of paper worth of clearance, I'm happy. I have yet to observe witness rub marks regardless of application, be it Detroit potholes or track-days.

 

et45, 215/45-17 rubbed on my bc coilovers. h&r 5mm spacers cleared things up nicely

 

I'm gonna have to agree with ryephile on both points. I run with very little clearance and I regularly check for any signs of rubbing and have found nothing.

 

i check clearances w/ a business card. if it fits, it fits. it isn't going to get any closer.

 

btw, i forgot to mention that after i put on the 5mm spacers i could only get about 3 turns on the lug nuts...so i got the tsw lug nut conversion kit. if you need to do likewise make sure you know if you need a 12mm or 14mm set.

 

You also didn't mention your wheel width. Offset is only part of the backspace equation.

You bring up a very good point regarding safety using wheel spacers; you should have >6 turns of wheel bolt thread going into the hub to maintain good safety margin. With the use of wheel spacers, longer bolts or going to a stud and nut conversion [which is another way to get longer threads] are the only safe solutions.

 

I have 5mm spacers and the tsw stud kit w/ my BCs for giggles.

 

true, not all 215's are created equal...i have the dunlop direzza sport z1 star specs...specs avail here http://www.dunloptires.com/dunlop/di...00000&zipCode=
hope that helps

 

--->oxtox; you reinforce my point from post #2, tire size and shape are a big factor if spacers are needed. Some tires, like Falken RT-615's, are very narrow and round in profile for their size. Others, like the Dunlop Star Specs you have, are quite wide and square in profile for their size. They might as well be totally different "sizes", yet they may have the same numbers.

...but, and I gotta rib ya here...you still haven't mentioned your wheel width. You need both wheel width and offset to calculate backspacing.

 

ah sooooo.....i have the oem sidewalk wheels 7"

i was confused as the rubbing wasn't near where the tire and wheel meet

thanks, and i will try to be more precise in the future sensei.

 

if you are getting spacers USE LONGER BOLTS OR A STUD CONVERSION KIT!!! I had to use spacers when I put my Wilwood kit on DIDNT use new bolts and had a wheel fall off!!! I was lucky that I was doing about 2mph and felt it just before it came all the way off!!! destroyed my hub in the process (brakes were fine!!!)

 

Every spacer has a corresponding bolt length - buy new bolts!

And, spacers are not necessary on all four wheels...if track is increased on the front axle, this wider stance will help to alleviate some understeer by helping the front tires perform more work. My track setup was 15mm spacers added to 17 x 7" BBS 38mm offset up front and 5mm spacers to the same wheel in back - a 10mm difference. Today I use 5mm spacers up fron only. The difference is still quite noticable.

The only problem with 15mm spacers - aside from potential premature bearing wear - is that the front tires do stick out into the wind. I felt the difference at high speeds - 110~120mph and higher with an otherwise stock body - no aero aids or aero band aids.

 

i'm about to install my BC coils this coming week. wheel width 7.5, offset +45 with 215/40R17 GS-D3 tires. still hoping i won't need spacers...

which rubs which? the tire to the spring? wheel to the strut?

 

mine was tire onto strut

 

had my BC coils installed a few hours ago. happy to report that with 7.5" wide & +45 offset wheels & 215/40 GS-D3 i got about 2-3mm clearance from the strut