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Rim/tire - diagram question by newfiejeff
Started on: 02-27-2014 06:58 PM
Replies: 19 (429 views)
Last post by: BrittB on 03-11-2014 10:59 PM
newfiejeff
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Report this Post02-27-2014 06:58 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

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Report this Post02-27-2014 08:03 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
The diagram says that 8.5" wheels will clear on the fender, but the rim will hit on the inside...so no they don't fit.
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newfiejeff
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Report this Post02-28-2014 03:01 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
So the red line on the left is where the rim would strike the car?
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Patrick
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Report this Post02-28-2014 07:55 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't 100% understand this diagram.

What are the thin vertical blue lines? Do they just signify where the outside edge of the factory wheels extend to?

And what are the white areas on each end of the grey (and yellow) "wheels"?

[This message has been edited by Patrick (edited 02-28-2014).]

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BrittB
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Report this Post02-28-2014 11:26 PM Click Here to See the Profile for BrittBSend a Private Message to BrittBEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think the white areas are is the actual tire itself.
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Patrick
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Report this Post03-01-2014 03:57 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BrittB:

I think the white areas are is the actual tire itself.


But there's nothing to indicate tire size on the chart (as obviously different width tires can fit each of the wheel sizes listed).
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newfiejeff
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Report this Post03-01-2014 04:10 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
Maybe the red is the suspension/brakes.
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Patrick
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Report this Post03-01-2014 04:48 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

Where's Joe Torma anyway? We need some answers!
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FieroBobo
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Report this Post03-01-2014 11:31 PM Click Here to See the Profile for FieroBoboClick Here to Email FieroBoboSend a Private Message to FieroBoboEdit/Delete MessageReply w/QuoteDirect Link to This Post
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 ~

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"Its nice to be important.
Its more important to be nice."

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fieroguru
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Report this Post03-02-2014 09:06 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
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.

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fieroguruperformance.com

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FieroBobo
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Report this Post03-02-2014 01:38 PM Click Here to See the Profile for FieroBoboClick Here to Email FieroBoboSend a Private Message to FieroBoboEdit/Delete MessageReply w/QuoteDirect Link to This Post
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 ~

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"Its nice to be important.
Its more important to be nice."

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newfiejeff
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Report this Post03-02-2014 07:44 PM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
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!!!!
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BrittB
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Report this Post03-02-2014 09:13 PM Click Here to See the Profile for BrittBSend a Private Message to BrittBEdit/Delete MessageReply w/QuoteDirect Link to This Post
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!
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fieroguru
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Report this Post03-02-2014 09:33 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by newfiejeff:

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.
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fieroguru
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Report this Post03-02-2014 09:38 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post

fieroguru

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quote
Originally posted by BrittB:

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.
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Report this Post03-02-2014 09:44 PM Click Here to See the Profile for BrittBSend a Private Message to BrittBEdit/Delete MessageReply w/QuoteDirect Link to This Post
I hoping they will extend out a little bit. My specialty is fiberglass so making fender flares would be a snap!
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newfiejeff
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Report this Post03-03-2014 05:34 AM Click Here to See the Profile for newfiejeffClick Here to Email newfiejeffSend a Private Message to newfiejeffEdit/Delete MessageReply w/QuoteDirect Link to This Post
So in saying all this, what is the best way to figure out what will work? It seems that the diagram has some flaws.
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fieroguru
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Report this Post03-03-2014 06:47 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by newfiejeff:

So in saying all this, what is the best way to figure out what will work? It seems that the diagram has some flaws.


Percy's 01201 - Percy's WheelRite Wheel Fitment Tool



http://www.jegs.com/i/Percy...Kl9rwCFYsWMgodVh8AWg

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.
http://www.fiero.nl/forum/Forum2/HTML/120740.html

[This message has been edited by fieroguru (edited 03-03-2014).]

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2.5
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Report this Post03-03-2014 10:09 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
So we need somebody to put labels on those lines in the diagram
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BrittB
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Report this Post03-11-2014 10:59 PM Click Here to See the Profile for BrittBSend a Private Message to BrittBEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BrittB:

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!


Tried them on and they fit, whoo-rayyy!



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