Lemme tell you y'all a story about 275 40 17s & 65 mustangs...complete with many pics

[dodgestang]

First off....thanks to Bill Gear...it took a while since the drop shipper sent my wheels to MO instead of MD...but I got wheels today and ran right out and get those 275 40 17 BFG DR I bought mounted

First thing that struck me was the size of these tires compared to my 255 40 17 on the same size rim

Pre-mounting research led me to beleive that they would end up being about 10.5 inch wide when mounted on an 8 inch rim...well that turned out incorrect...must be differences in brands since I got that measurement from another brand (iirc). As you can see my BFG KDs are 10 inches bulge to bulge

And it turns out these DRs are......11 :horror:

So some of you may remember how I posted about having 11.5 inches of clearance on one side...and 10.5 on the other...well that hasn't changed...so I'm already off to a bad start.

Mounting up the tires onto the car I didn't run into too many problems. As you can see, I clear the leaf springs ok

Passenger side:

Driver side:

But then I run into a small problem...front of the wheel well on passnger side there is light contact...but this is something that could be 'cured' easily with a hammer

And I have no such problems on the driver side:

So after I mounted them on the car and bolt them on, I drop the car and snap some pictures:

Passenger side - aside from small contact with the inner fender that can be fixed this side sure seems to fit:

Driver side - ohhh noo....this side doesn't seem too good :

And for some other interesting tidbits...I rolled them all through some light dirt.

275 40 17 on a 17x8 BFG DR = 8 inch contact patch at standard pressure

255 40 17 on a 17x8 BFG KD = 7.75 inch contact patch at standard pressure

Only benefit I gain (or IMO anyone else with a 65/6 mustang) with these is tire compound, IMO they can not be run on the street as it sits now and are only good for the straight line drags. Now I am hoping to figure out a way to gain .5 inch on the driver side, the passenger side easily fit the car, but given that I can't really get closer to the leaf spring than I already am I don't think there is a way to make these work long term for me and this car.

Bottom line: Half (arsed) fit.

 

[1320stang]

I think I'd pull the U-bolts and slot the hole in the spring perch on the housing and on the plate 1/4" with a die grinder. If you have access to a welder, I'd weld up the difference.

 

[dodgestang]

I think I'd pull the U-bolts and slot the hole in the spring perch on the housing and on the plate 1/4" with a die grinder. If you have access to a welder, I'd weld up the difference.

Not sure I understand what you are saying. I could concievably knock the perch off the housing and move it a little....that would prob introduce a slight angle to the leaf spring but wouldn't nessecatily move the rear around....and would have to add a panhard bar to manually locate the rear to keep it from moving around...and panhard doesn't fit with my exhaust setup that goes over teh axle and out the back valance.

 

[1320stang]

Nick, there's a bolt that runs thru your springs right? The hole in the spring perch keeps it from sliding off the perch. If you'll grind the hole on the perch out on the side the tires stick out, you should be able to scoot the housing over 1/4" to allow the rear to be centered. Does that make sense?

 

[dodgestang]

I understand what you say now...but...I have a 57 ford 9 inch...the perch mounts are sorta 'captured' by the u bolts so there isn't any play to scoot the leafs over on the perch even I move the centering hole. I would have to move the whole mount...but that also won't really move the leaf springs any....just the rear in relation to them...not sure if I have the clearance to move the tire closer to the leafs.

I will have to look tomorrow to see if I have any play between the leafs and the u bolts to see if it is possible to 'eek anymore distance there.

 

[steel1212]

Why do you have an inch diffrence on what side versus the other? I didn't seem to have that problem? Also what is your backspaceing on these wheels and are they 17x8s?

Also if you massage the inner fender on the one side why do you say you can't run them on the street? I mean the other side does stick out a touch for some reason.

 

[dodgestang]

Why do you have an inch diffrence on what side versus the other? I didn't seem to have that problem? Also what is your backspaceing on these wheels and are they 17x8s?

Also if you massage the inner fender on the one side why do you say you can't run them on the street? I mean the other side does stick out a touch for some reason.

They are on 17x8 4.75 wheels.

This difference is prob from quarters that were put on the car prior to my owning it. (both sides were done).

I'm not concerned about the inner fender that is an easy fix. I can't run them on the street BECAUSE the wheel sticks out past the fender on the driver side. My suspension works on my car...its is not held up by any artifical means (like some people do with air shocks) so the first bump I hit above 25 MPH and my fender will be damaged by hard contact with the tire.

 

[steel1212]

How close is your tire to your outer fender? Do you have a pic that shows that? Is your over all tire height 26"? Do you have reverse mideye rear springs or standard mid eyes?

 

[Jimmys66]

My car's the same way, the drivers side is in farther than the pass. side.

 

[66Runt]

Have you checked your *frame* to insure it's straight?

the reason I ask is that the distance from the wheel to the springs looks the same on both sides. And the springs connect directly to the frame at the same points on the subframe. So I am thinking either your body is off, your rear subframes are off or your spring eyes are tweaked. Or possibly a combination of the above.

When you got the car back from the body shop did you have them throw it on a 4 wheel alignment rack? That will tell you wether it's the body or the the subframe.

One thing you want to make sure of is that your rear tires are directly in line with the fronts. Otherwise you car will handle different between right and left turns in performance driving.

As a side note: Is the back spacing on your front rims also 4.75"?
Personal interest, as I'm getting ready to order 17x8's for my car and would really like to run 4.75" BS on the front.

Thanks,

Scott

 

[dodgestang]

the reason I ask is that the distance from the wheel to the springs looks the same on both sides. And the springs connect directly to the frame at the same points on the subframe. So I am thinking either your body is off, your rear subframes are off or your spring eyes are tweaked. Or possibly a combination of the above.

When you got the car back from the body shop did you have them throw it on a 4 wheel alignment rack? That will tell you wether it's the body or the the subframe.

The 10.5 and 11.5 from side to side existed prior to the incident with the tractor trailer. It is related to how the PO installed the passenger side rear subframe when he replaced it and it is not exactly perfect so my passenger side leaf sits slightly tweak. The driver side subs have not been touched so I believe the stock mustang has 10.5 to 11 inches (depending on how the rear quarters are hung)

 

[dodgestang]

My car's the same way, the drivers side is in farther than the pass. side.

I have heard that years of peg leg running tends to make this happen on some cars. I have also heard that with the quality and workmanship skill employeed (or lack there of) by someone who puts on new rear quarters its not all the uncommon to have variance like this.

 

[dodgestang]

How close is your tire to your outer fender? Do you have a pic that shows that? Is your over all tire height 26"? Do you have reverse mideye rear springs or standard mid eyes?

Mid eye 5 leaf...and 25.7 inches.....the picture is already in the post steel....the tire is well past the fender.

 

[steel1212]

No I can see its past it I mean from bottom of the fender to the top of the tire. I have a 26" tall tire and have plenty of room between those 2 points. I'm thinking that my racing shackles may have raised the rear of my car a little though as I mistakenly put them on the wrong setting trying to set it lower and ended up setting it higher . I guess its helped me in the end after all though.

 

[dodgestang]

No I can see its past it I mean from bottom of the fender to the top of the tire. I have a 26" tall tire and have plenty of room between those 2 points. I'm thinking that my racing shackles may have raised the rear of my car a little though as I mistakenly put them on the wrong setting trying to set it lower and ended up setting it higher . I guess its helped me in the end after all though.

My suspension goes through full range of motion Steel, so it will hit. The 255s scrubbed on the lip till I rolled it. Tires sticking out past the fender is 1979 even if my suspension was 'jacked' up and not able to move.

 

[steel1212]

Mine goes through the motions as well don't know what your meaning by, "My suspension goes through full range of motion Steel, so it will hit". If your driver's side looked like your passenger side would you say it was streetable? If so doesn't your passenger side sit right below your fender lip as well? I still want to see a side pic of your car as I think your tire is closer to your fender lip than mine is.

 

[66Runt]

The 10.5 and 11.5 from side to side existed prior to the incident with the tractor trailer. It is related to how the PO installed the passenger side rear subframe when he replaced it and it is not exactly perfect so my passenger side leaf sits slightly tweak. The driver side subs have not been touched so I believe the stock mustang has 10.5 to 11 inches (depending on how the rear quarters are hung)

That fits with what I thought. I would suggest, making sure your front and rear wheels are in line. IMO that is the most important issue you face.

Do you have 4.75" back space on your front rims as well?
Thanks,

Scott

 

[dodgestang]

That fits with what I thought. I would suggest, making sure your front and rear wheels are in line. IMO that is the most important issue you face.

Do you have 4.75" back space on your front rims as well?
Thanks,

Scott

Yes and yes.

 

[dodgestang]

Mine goes through the motions as well don't know what your meaning by, "My suspension goes through full range of motion Steel, so it will hit". If your driver's side looked like your passenger side would you say it was streetable? If so doesn't your passenger side sit right below your fender lip as well? I still want to see a side pic of your car as I think your tire is closer to your fender lip than mine is.

Not meant anything towards you....back in the late 70s everyone ran wide tires sticking out and air shocks to keep their fenders off the tires.

The passenger side as stated previously fits the car with minor tweaking to the inner fender, it is under the outer fender and the suspension has free range of motion up and down with no contact.

The distance from the top of the tire to the fender is not a very useful indicator of fit. My car is lowered from stock height so I am sure that I have less distance from fender to tire, when a tire is under the fender it wouldn't matter one way or the other how much space there was between the top of the tire and the fender. I will see about a picture later, I am in the middle of solving a roller idler arm installation issue.

 

[steel1212]

The passenger side as stated previously fits the car with minor tweaking to the inner fender, it is under the outer fender and the suspension has free range of motion up and down with no contact.

This is the part I'm trying to figure out. I'm assumeing that your passenger side is the same as both my tires just right under the outter fender lip. If that is the case, and you say that works, why the driver side doesn't work. I understand it doesn't work from a looks stand point as it sticks out but I don't see how that is any diffrent than the passenger side functionally?