1986 Fiero 5 speed Here is the diagram that I am not quite sure of. I have a chance of getting 4 18inch rims 48mm offset, 8.5 inch rim size. The tires that is coming with it is 225/40/18, would they fit? I am looking at this diagram and it makes sense but to me it really don't answer my question.
This diagram is not the most self-explanatory version of this diagram. (I have seen better ones.) I will try to explain the diagram as best I can. (I may be wrong, however. Please correct me if I am.)
The Red line on the left side of the diagram is the rear strut line, where a stock wheel would hit the suspension.
There are 2 Grey lines on the far Right side. The 1st Grey line, (farthest to the right), is the outer edge of the Front wheel well. The 2nd Grey line, (slightly to the left of the 1st), is the outer edge of the Rear wheel well
The single Blue line just slightly to the left of the 2 Grey lines, is the outer edge of a 15x7 +30mm wheel, on the front of an ‘86-'87, or the Rear of an ‘86-'88.
The double Blue line, to the left of the single Blue line, is the outer edge of the 15x6 +37mm Front wheel on an ‘88.
The White edging on both sides of each wheel is for the wheel lip, (approx. ¼”, +/- )
I hope this proves helpful.
~ Bob ~
------------------ "Its nice to be important. Its more important to be nice."
Originally posted by FieroBobo: The Red line on the left side of the diagram is the rear strut line, where a stock wheel would hit the suspension.
While the tool is pretty decent on all the dimension lines on the outboard side, the Red line for the Strut interference isn't a fixed dimension (like the edge of the fender) like it is shown and different between the 84-87 and the 88's and the interference on the backside is different between the front and rear.
16" wheels will hit the rear strut/upright flange first on all years 17" wheels will pass over the strut/upright flange on the 84-87 and give them nearly 1" more rearward space (with coilovers), but 17's on the 88's are still limited by the strut/upright flange. 18" wheels will be limited by the rear strut body for all year and depending on where you place the bottom of the coil over sleeve the point of contact can be the coilover spring or the strut body itself (giving you about 1/2" more room). The 88's also have to keep a close eye on trailing link clearance (which also changes with wheel diameter). Also, since the 88 strut is mounted 1" further inboard at the top, it gets further from the wheel than the 84-87 as the wheel diameter increases beyond 18"
For example, a 18 x 9 with 48mm offset will fit the rear of an 88 Fiero (with coilovers) almost perfectly, but the diagram shows a 9" wheel with 40mm offset hitting the strut and sticking out slightly on the outer edge. With 8mm more offset, the wheels are tucked in deeper to fix the outer edge issue and should interfere more on the inside, but they fit because of 18" diameter allowed more clearance to the back side.
Similar issues happen on the front between the years (differences in a-arm shape) and chassis height (a-arm angles) and wheel diameter also come into play with clearance on the backside too.
Fieroguru, THANKS for your input and corrections. I was trying to be helpful, (as best I could), to the prior posters on this thread. Unfortunately, I am not nearly as knowledgeable as you are on the subject.
Thank you for sharing your knowledge and giving us all a clear detailed and in depth clarification on this subject. I think that the info that you have given us will go a long way toward clarifying the perrenial questions regarding "What size tire/wheel will, (or won't), fit on the back of my Fiero."
~ Bob ~
------------------ "Its nice to be important. Its more important to be nice."
Well, I have TSW rims that are suppose to be 18x8 with 35mm offset but in doing the math they are really 9 inches wide and in trying to install them they hit the stock struts. Bummed now!
So the 18inch 48mm offset with 8.5 inch rim will strike the strut? So if this is the case then I fully understand the diagram.
Thanks for all the help everyone!!!!
All it says is 8.5" wide wheel with 48mm offset will hit the strut, but without any reference to wheel diameter. This is a weakness in the tool as clearances do change and an 18 x 8.5 with 48 offset should fit any year once the strut is converted to coil overs.
Well, I have TSW rims that are suppose to be 18x8 with 35mm offset but in doing the math they are really 9 inches wide and in trying to install them they hit the stock struts. Bummed now!
I assume they hit the stock spring perch. If you convert to coilovers then they should clear the strut, but may not tuck in under the body unless they have a deeper offset like 48 mm.
I show using this tool on an 88 fiero in this thread and show the interference areas and the opportunities for more rear ward clearance by going to 18" wheels in the rear of an 88. //www.fiero.nl/forum/Forum2/HTML/120740.html
[This message has been edited by fieroguru (edited 03-03-2014).]
Well, I have TSW rims that are suppose to be 18x8 with 35mm offset but in doing the math they are really 9 inches wide and in trying to install them they hit the stock struts. Bummed now!