Quest to fit 15x12's - a little bit of fat work of course

[BigPinoyHunk]

Ok the old timers here know that i use two sets of wheel sets. one for the street and one for the strack. of course the obstacle is my huge 04 cobra brakes. here's my current combos:

Track:

15x4's with 26x4-15 tires (one inch spacer)

15x10's 5.5BS with 28x10.5-15 tires

Street:

17x8 4.5BS with 235/45/17 tires

17x11 with 7.5BS and a 315/35/17 tires

on my street wheels being so deep in BS, i can fit them because the rear swaybar is removed and the tires are only 25.7 inches tall. to make these fit well, all i had to do was hammer in the wheel well a tiny bit. but i eventually ended up using a 1/2 spacer to have the look of the wheel being closer to the fender lip.

for me to get a 15x12 in there with a 7.5 BS and a 2 inch taller tire would be to modify the front of the wheel well ONLY. a wheel tube or even a full mini tube isn't neccessary with these cars. doing some measurements, i have 1.5 inches of clearance before my street tires touch the leaf spring, there is 2 inches before the tire even comes close to touching the inner fender well in the middle. if i were to mount a 28 tall tire in there now with a 7.5 BS, it'll hit the front fender well.

with talks with a local fabricator, a full mini tube isn't neccessary which is 1500. just modifying the front of the wheel well is right and we will go with this. it looks like it'll be easy to get a 15x12 in the fender wells even with plans of going with a 28x10.5W-15 tire or with a 29 tall with either a 11 or 12 wide.

the only thing i also gotta do since i got large cobra brakes is to machine down my brake line so the wheel will slip into over the banjo bolt and fitting!

man, do we got large wheel wells or what?

 

[marks73]

You know better by now!

:worthlesswithoutpics:

 

[BigPinoyHunk]

in this pic you can see that i have a wide 12.7 wide 315/35/17 tire wrapped around my 17x11 7.5BS wheels with a 1/2 spacer (will work without but comes really close to inner fender well)



IN this pic you could see that i got 1.25 inches of clearance from tire to leaf spring. this will DECREASE to .75 inches without the spacer.



in this picture you could see from the inner fender well that i got 1.5 inches of clearance which will DECREASE to 1.0 inches without the spacer.



right next is the clearance between a 25.7 inch tire to the fender well thats is huge. it looks like i got about 2.25 inches of clearance and with me wanting to use a 29 inch tall slick, this will DECREASE to .75.



this is the front fender clearance from the tire which is huge as well, its almost 3.0 inches clearance which will DECREASE to 1.5 inches with a 29 tall slick.



here is the problem if you want this much BS and a tire taller than 26 inches. is this part of the fender well. this is where you/i will have to get modified to fit this much BS and have a 28-30 inch tall tire.

i am needing a little bit of a taller and wider tire for the new 660HP 521stroker alumium headed coming back (more compression much higher flowing heads this time so it equals more power). here is a few tires i am wanting to get into.

http://www.summitracing.com/parts/gdy-2797

this tire is really wide and offers not nearly as much bulge like other slicks.

http://www.summitracing.com/parts/mtt-3057

i want to go with this one thats not as wide in a 11 inch or get the 10.5W cheater tire but these offer much more bulge.

by the time i get that 15x12 in there with a 13.2 bulge tire in there, there should only be about 1/2 clearance between the tire and leaf spring which is minimal on a track condition. of course this is only at the track and i will stick with my 17s on the street.

 

[Silverback]

Track:

15x4's with 26x4-15 tires (one inch spacer)

15x10's 5.5BS with 28x10.5-15 tires

I asked in another threads, do you have pics posted or can you post pics? I was also wondering about details, but the 5.5bs answers that (and is what I expected as opposed to what a few have posted that you run that I didn't think would fit).

 

[BigPinoyHunk]

Track:

15x4's with 26x4-15 tires (one inch spacer)

15x10's 5.5BS with 28x10.5-15 tires

I asked in another threads, do you have pics posted or can you post pics? I was also wondering about details, but the 5.5bs answers that (and is what I expected as opposed to what a few have posted that you run that I didn't think would fit).

questions?

 

[Silverback]

Thanks... do you have pictures of them from other angles/closer up, so I can see how they fit (yea, i know, always wanting more )?

From that one it looks like they tuck in surprisingly well (and almost look small). It's funny what the proportions of these cars do to tires (the car isn't any bigger than my TA, funny thing is that same custom fit car cover fits both like a glove, and that tire would look really big on that car).

I'm actually surprised that the 26" tall front doesn't look too small on the front.

I'm almost tempted to find some chevy pattern adapters and try some of the bigger wheels/tires I have sitting around for my TA. I have a set of Z06 wheels with 305/35-18's on the back rims that look massive on that car that I'm wondering if they'd look good on the Mach.... Huh, I just remembered that the race tires for that car are mounted on some dual bolt pattern Draglites, 1/2" offset, those will probably bolt right on, 15x9 for the rear with 5.5bs should be really close, don't remember whats on them but I know they're 28" tall...

 

[BigPinoyHunk]

Thanks... do you have pictures of them from other angles/closer up, so I can see how they fit (yea, i know, always wanting more )?

From that one it looks like they tuck in surprisingly well (and almost look small). It's funny what the proportions of these cars do to tires (the car isn't any bigger than my TA, funny thing is that same custom fit car cover fits both like a glove, and that tire would look really big on that car).

I'm actually surprised that the 26" tall front doesn't look too small on the front.

I'm almost tempted to find some chevy pattern adapters and try some of the bigger wheels/tires I have sitting around for my TA. I have a set of Z06 wheels with 305/35-18's on the back rims that look massive on that car that I'm wondering if they'd look good on the Mach.... Huh, I just remembered that the race tires for that car are mounted on some dual bolt pattern Draglites, 1/2" offset, those will probably bolt right on, 15x9 for the rear with 5.5bs should be really close, don't remember whats on them but I know they're 28" tall...

i'm going to the track on saturday so i can snap some pictures of it then. let me tell ou though, with the 4.5 offset, it'll come somewhat close to the fender but you got to have them rolled for COMFORT. also, if you have 4 leaf springs then you might need to worry if you want this wide rim and not a rolled lipped.

if you want a 15x10 and not worry about the lip, get a 6 - 6.25 backspacing with a 275 tire or wider. however if you want that nice offset look and have the tire closer out to the wheel fender (like me) get a 15x10 with a 5.5BS but stay with a 26 tall tire. the top tire to fender clearance will be more than 2.5 inches like mine now and the suspension won't compress hard enough to come down on the tire and will not go past the fender. i believe most people will use a 295/50/15.

all in all, get a 5 leaf spring (i have a used set in the backyard that i want to get rid of and will part ways cheap).

in my case, lotsa power, means u need lotsa suspension and tire to hook it up.

 

[Finmach]

Olie, I have in similar Mach 1 a 1" narrower rear than the normal '71-'73 rear is, so we can think that to my wheel BS you would need to add 1/2" of BS to get same results as I do.

I use MTT # 3056ST 29.5x9-15 as track tire, it's section width is 11.40". Wheels are 15x9 Weld Prostars with 5.50" BS. By using a 6.00" BS wheel with 9" overall widht wheel you would have it sitting like my car has.

Front wheel well is the closest possible place to hit the tire. I've got app. 1" space to the outer wheel well. Inner fender has been bend & hammered.

My car sits fairly low from the rear, so I wanted to keep the tires under the fenders. With taller rear with std eye leafs I would be able to bring the tire closer to the fender lip without hitting the tire in a bump.

Back the day I had a 325/50-15 = 28 x 13.50R15 Mickey Thompson street radials. I had also a stock lenght rear axle. With 15x10 Magnum 500 wheels with 6" BS the fitment was nearly perfect with std eye leafsprings. Here's few shots:

this was the first test shot with unmodified wheel wells.

Plenty of space = just about enough.

Later when the rear was lowered, I was forced to give up from the big meats... If you're using the big puppies only at the track, I would go for the 28" tall and with 13.50" wide like the MT 325/50-15. By going to taller tire with similar section width you're looking for big time tire rubbing if unless you're going to raise the rear skyhigh. Your car has a nice stance & rake, so I wouldn't lift the rear. Either stay in wide 28" or go for narrower but higher tire.

 

[BigPinoyHunk]

Olie, I have in similar Mach 1 a 1" narrower rear than the normal '71-'73 rear is, so we can think that to my wheel BS you would need to add 1/2" of BS to get same results as I do.

I use MTT # 3056ST 29.5x9-15 as track tire, it's section width is 11.40". Wheels are 15x9 Weld Prostars with 5.50" BS. By using a 6.00" BS wheel with 9" overall widht wheel you would have it sitting like my car has.

Front wheel well is the closest possible place to hit the tire. I've got app. 1" space to the outer wheel well. Inner fender has been bend & hammered.

My car sits fairly low from the rear, so I wanted to keep the tires under the fenders. With taller rear with std eye leafs I would be able to bring the tire closer to the fender lip without hitting the tire in a bump.

Back the day I had a 325/50-15 = 28 x 13.50R15 Mickey Thompson street radials. I had also a stock lenght rear axle. With 15x10 Magnum 500 wheels with 6" BS the fitment was nearly perfect with std eye leafsprings. Here's few shots:

this was the first test shot with unmodified wheel wells.

Plenty of space = just about enough.

Later when the rear was lowered, I was forced to give up from the big meats... If you're using the big puppies only at the track, I would go for the 28" tall and with 13.50" wide like the MT 325/50-15. By going to taller tire with similar section width you're looking for big time tire rubbing if unless you're going to raise the rear skyhigh. Your car has a nice stance & rake, so I wouldn't lift the rear. Either stay in wide 28" or go for narrower but higher tire.

weird how we are getting different measurements on our same cars. however i can see that you got drums and i got disc conversion which pushed out my wheels out a little further.

pictured i have a 7.5 BS with a .5 spacer.

 

[BigPinoyHunk]

after the track yesterday, i dropped off the car at the fabricators and we are going to see what can be done to put in some fat meat tires under there to handle not only the 521 stroker, but the trickiness of sticking a manual shifted car to the track.

ideally we just modify the front of the wheel well and fit 15x12 with 29.5x10.5w-15 slicks. lucky part is that the fabricator has that size tire available in the shop to do a test fitment.

he did talk about possibly relocating the leaf springs and make it super easy with a mini tub of course. but by then, i could fit 15x14's with 31x13-15 slicks in there. but i might lose the e-brake which is a must with a stick car.

i'll get a call wednesday to see whats up with the whole thing.

with this being said, i might have a set of wheels and slicks for sale!

 

[cazsper]

What wheels are you going to be selling? though I would love your engine (if it's still available) it will take forever to save up for now that I'm not working.

 

[BigPinoyHunk]

What wheels are you going to be selling? though I would love your engine (if it's still available) it will take forever to save up for now that I'm not working.

i might be willing to sell either my street 17s or my track 15's.

if i sell my 17's i'll use my old track 15's as street tires ( need something tall and skinny for the front tires ) and permanently use spacers in the front.

or just sell my 15's that were for the track. of course, i'll sell the wheels with tires!

 

[BigPinoyHunk]

this quest is now on hold because my fabricator wants me to make better upgrades in redoing suspension. instead of relocating leaf springs and still having leaf springs, we are now doing a ladder bar suspension with poly bushings.

since we are doing this, we won't have to relocate springs anymore because so we will just need to mini tube car until the frame.

also, the entire CALVERT rear suspension is for sale!

 

[Finmach]

weird how we are getting different measurements on our same cars. however i can see that you got drums and i got disc conversion which pushed out my wheels out a little further.

pictured i have a 7.5 BS with a .5 spacer.

Xoliex, sory it took so much time, I've been extremely busy with my family. My wife gave birth for our second boy, whew, I've been changing diapers, playing with the older one (3yrs) and dreaming from getting to garage. Now back to topic!

If you have 15x11 rear wheels with 7.5 BS, it equals 15x9 with 6.5 BS – it mounts the tire to the exactly same centerline in the wheelwel as the 15x11 with 7.5 BS.

Good point from the discbrakes, they tend to have thicker bolt centers = it makes easily a quarter of an inch difference. Main difference with our similar cars comes from the different wheel width. Back the day I had only 15x10 wheels with 6” BS and with std. width rear axle with drums. Now I got 1” narrower rear than the std. and with disc brakes – so there comes the main difference. As far as I am considered the Cobra brakes has very thick brake bolt center.

BS only defines that how many inch does the wheel goes inwards from the wheel pad. The wider wheel the more BS you’ll need to be able to place the tire to the same centerline in the car. Tire will only bulge more with narrower wheel, with wider wheel the less the tire will bulge. You will need to calculate also the tire section width when choosing proper width & BS wheels.

But you will allways need to figure out that how much does the tire bulge per side of the wheel, it can be done when you now know how. I have measured many times my wheelwels and have allways managed to get proper ET / BS wheels with the tires I have wanted. Fitment hasn’t ever been an issue.

Moving to Ladderbar rear surely gives you plenty of room. I like your idea in every way but I would go with 4-link rear, since it doesn't attack the rear housing attaching points that much. Otherwise I would forget the minitubbing and hit it to the 15x14 or 15x15 rear wheels and some huge donuts. It would make your TKO600 to take some extra punishment when dumping the clutch!!!

 

[BigPinoyHunk]

weird how we are getting different measurements on our same cars. however i can see that you got drums and i got disc conversion which pushed out my wheels out a little further.

pictured i have a 7.5 BS with a .5 spacer.

Xoliex, sory it took so much time, I've been extremely busy with my family. My wife gave birth for our second boy, whew, I've been changing diapers, playing with the older one (3yrs) and dreaming from getting to garage. Now back to topic!

If you have 15x11 rear wheels with 7.5 BS, it equals 15x9 with 6.5 BS – it mounts the tire to the exactly same centerline in the wheelwel as the 15x11 with 7.5 BS.

Good point from the discbrakes, they tend to have thicker bolt centers = it makes easily a quarter of an inch difference. Main difference with our similar cars comes from the different wheel width. Back the day I had only 15x10 wheels with 6” BS and with std. width rear axle with drums. Now I got 1” narrower rear than the std. and with disc brakes – so there comes the main difference. As far as I am considered the Cobra brakes has very thick brake bolt center.

BS only defines that how many inch does the wheel goes inwards from the wheel pad. The wider wheel the more BS you’ll need to be able to place the tire to the same centerline in the car. Tire will only bulge more with narrower wheel, with wider wheel the less the tire will bulge. You will need to calculate also the tire section width when choosing proper width & BS wheels.

But you will allways need to figure out that how much does the tire bulge per side of the wheel, it can be done when you now know how. I have measured many times my wheelwels and have allways managed to get proper ET / BS wheels with the tires I have wanted. Fitment hasn’t ever been an issue.

Moving to Ladderbar rear surely gives you plenty of room. I like your idea in every way but I would go with 4-link rear, since it doesn't attack the rear housing attaching points that much. Otherwise I would forget the minitubbing and hit it to the 15x14 or 15x15 rear wheels and some huge donuts. It would make your TKO600 to take some extra punishment when dumping the clutch!!!

i have a 17x11 wheel not a 15x11.

with the wheel fitment, the biggest issue is the front fender well not too much the leaf. once a wheel housing is tubbed or mini tubbed, the leaf spring comes to hit. well, now i've gone to ladder bar, that is out of the way since its more inward.

the thing with going past a 15x12 is that the most BS u can get is a 8.5 with either a 12 or 14 wide. so unless somebody starts making deeper wheels, i'm stuck with a 12 wide. besides, a 12 on a 11 or 12 inch slick is huge.

with the ladder bar and four link, many racers around here agree that four links have to be hit super hard to work for you entirely and ladder bars are easier to work with on modern motor cars like ours. and besides, many fabricators around here say that it cost twice as much to install a four link than a ladder bar.

 

[Finmach]

What I ment was that the ladderbar is attached to the rear frame from one point per side and all the stress goes through that point where the upper & lower bars attach to eachother. I’ve seen ladderbar to rip off from the frame – it was ugly, I haven’t seen any 4-link break off from the frame. Skilled welder will probably do the job, so no worries. Otherwise I agree with you, ladder bar is easyer way to go and cheaper too, you can almost fabricate ladders without lifting the trunk floor & or rearseat floor, try that with 4-link… no go hot shot! 4-link needs higher space than ladders.

If you want a custom width aluminium wheels, this is your place to visit. They can modify your existing wheels to almost any BS & width you desire.

http://www.weldcraftwheels.com/index-1.html

 

[Silverback]

Arg... this is frustrating.

xoliex- you list everything from a 10" wide rim with 0 offset to an 11" wide rim with 1.5" offset in as fitting, you're literally moving your tire centerline in and out by 1.5".

Finmach- if I'm keeping track of your posts, you seem to be suggesting that you need a 1" offset in "but with thicker disk brake hubs" to fit the widest tires on the back, but I don't know how much wider those hubs are. I don't know what disk brakes you're running but the only car I know of that came with both disks and drums (iron and aluminum drums also) on the same rear axle added a 1/8" spacer with iron drums vs no spacer with the aluminum and I think no spacer with the disk brakes. I would guess that if yours are wider its in the 1/8-1/4" range, which means that you've got something like the equivalent of a 3/4-7/8" offset in wheel on a stock axle car, right (from the pics it doesn't look like you have any extra room inside or outside)

So what offset to do you think you'd need to run something like a 325/50 or a 295/55 rear tire with a stock rear axle/suspension assembly?

 

[Finmach]

Arg... this is frustrating.

So what offset to do you think you'd need to run something like a 325/50 or a 295/55 rear tire with a stock rear axle/suspension assembly?

Silverback, I understand your frustration, sorry for any inconvenience and I agree with you. Speaking from myself, it doesn’t help anyone me to give you exact measures from my own rearaxle if I have a different width rear than the standard, I could have written it more precisely. Good point and well taken!

So IMO, with stock axle with stock drums with wheel with app. ET 13 positions the wheels in the center of the wheel well. By using 15x10 wheels it needs to have 6” bs to get it in the center equals 15x10 ET13 wheel. I was able to mount 325/50-15 ET Street Radial (section width 13.10”) tire to stock wheel wells as you can see in the earlier pictures with the ET street radial pattern pictures and it was on the edge. You cannot use mid-eye or reverse eye leafs by then, since the tire is underneath the fender lip. With stiff std. eye rear leafs you can use those tires mentioned above. If you would use a MT ET Street Radial 295/55-15 tire (section width 12.00”), then you could bring the wheel more inner wards to make more room to the fender clearance. I would do it by adding bigger ET to wheel ET 25-26 equals 15x10 wheel with 6 1/2” BS, that way the tire would move closer to the leaf spring still leaving enough clearance and it would add more tolerance between tire & fender. You can use also the 15x10 BS 6" wheels with the 295/55-15, it only gives bigger tolerance between tire & leaf spring and to the inner fender area.

F.ex. If you would use 15x12 wheels in my stock rear & stock drums it would need a 7” BS to be able to get the position in the wheel to the center. By then I could only use tire maximum of 325/50-15 (13.10” section width) without hitting the fender well. 325/50-15 tire with15x12 wheel with 7” BS will position the tire exactly to the same place (centerline) as does 15x10 wheel with 6” BS. This is not a rocket science but I am not sure have I written it clearly enough.

 

[Tnfastbk]

Arg... this is frustrating.

xoliex- you list everything from a 10" wide rim with 0 offset to an 11" wide rim with 1.5" offset in as fitting, you're literally moving your tire centerline in and out by 1.5".

Finmach- if I'm keeping track of your posts, you seem to be suggesting that you need a 1" offset in "but with thicker disk brake hubs" to fit the widest tires on the back, but I don't know how much wider those hubs are. I don't know what disk brakes you're running but the only car I know of that came with both disks and drums (iron and aluminum drums also) on the same rear axle added a 1/8" spacer with iron drums vs no spacer with the aluminum and I think no spacer with the disk brakes. I would guess that if yours are wider its in the 1/8-1/4" range, which means that you've got something like the equivalent of a 3/4-7/8" offset in wheel on a stock axle car, right (from the pics it doesn't look like you have any extra room inside or outside)

So what offset to do you think you'd need to run something like a 325/50 or a 295/55 rear tire with a stock rear axle/suspension assembly?

Buy you one of these and you can measure what you need for your car

http://www.jegs.com/i/Percy's/760/01201/10002/-1?CT=999