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Old 07-16-2005, 04:34 PM
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Default Narrowing and backspacing.

First off, how much can you narrow a Strange 12 bolt without having to relocate the springs and lower control arms? What are the pros and cons of relocating these parts? I'd like to take off as much as I can without having to relocate anything to remove rotating mass and to have a nice dish on the wheels as well as tucking the tire. I currently have 15x10 Bogarts with 7.5" backspacing. I plan on buying another set of 15x10 Bogarts, but need to decide on what backspacing. I will be removing the parking brake as I dont use it anyway. Again I want narrow the rear end and put more backspacing as much as I can without having to relocate the springs and LCAs. Am I making a bad choice by not relocating them? Lastly, how much are ya'll paying for a set of axles and to get your rear end narrowed? Thanks.
Old 07-16-2005, 04:47 PM
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I went 3" per side and 15x10 with a 5" backspace I think it looks real nice.
Old 07-16-2005, 06:06 PM
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Did you have to relocate the springs and LCAs and what size tire are you running?
Old 07-16-2005, 07:14 PM
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3" to 3.5" narrower and everything stays in the same location. You can get away with a little more backspacing to get some nice tuck. You may want to offset the LCA to get 28x10.5 W's to not rub. Otherwise it all fits in there with no other changes.
Old 07-16-2005, 08:17 PM
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an you fit the w's w/o the narrow rear end? Could you not just offset the rim differently?
Old 07-16-2005, 08:45 PM
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Well if I wanted the rims and tires to be in the same location as it is in now and I narrowed the rear end 3" per side, then I would get 4.5" backspacing since I have 7.5" now. Is that correct? But if I wanted to have a little more tuck, I would need to bring it out some to 5" of backspacing. So if I did the most common setup which is 3" per side with 5" of backspacing on a 15x10 wheel, I wouldnt have to relocate the springs and LCAs? I dont think I'm gonna end up doing the wide version of the 29.5x10.5, just the regular width. I think it'll be enough for my setup. Of all the searching I did through this section, I didnt find anyone to do anymore than 3" per side. Anyone out there do more than that or know of anyone that has? Thanks.
Old 07-16-2005, 08:54 PM
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Ideally we could use a rim with 8" of backspacing, but since 7 or 7.5" is the most you can get in a commercial rim you can't do much. Because you are narrowing the rear end your choices of commercial backspacing allows you to get a little more tuck. So a 5" BS rim will be more ideal. You will not have to relocate your shocks or your LCA, although offsetting the LCA is not a bad idea. Nothing a small spacer can't help with either if you are a pinch too tight. For the most part you should be able to bring that all in, but it is entirely dependent on your section width.

You can fit W's with and without the axle being narrowed. The biggest advantage of narrowing is you can move everything in a bit, loose some of the weight and have an added bonus that you get the axles in the range of more commercial rim sizes that make the tires look nicer on the car. It's certainly not a huge improvement in performance, but if you have an axle that can be narrowed it's only a couple hundred dollars. And if you are buying a new axle, it's worth it to just get it shorter. BTW, 40 spline axles can not be re splined and you will have to get new axles if you are working with those. I'm not sure about 33 and 35 splines, but I think that most of them can be resplined.
Old 07-16-2005, 09:10 PM
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Well narrowing the rear end I want to do for weight savings, less rotating mass, so that I can tuck more tire, and to have a deeper dish for a better/meaner look. 3" per side is the ideal amount that should be taken off right? I'll have to see how much space I will have when I mount the tires on to see if I need to relocate the LCAs. I'm sure there are others out there that are running 29.5x10.5 with a narrowed rear end and could tell me if its gonna need to be relocated or not. If I do, I guess its no big deal. What's involved? Also, if I have to relocate the LCA, does it mean that I have to do the spring as well? I'm running 35 splines I believe. Whatever Strange 12 bolts for our cars usually come with. From what Strange told me, my axles cant be shortended because there is only 3" of spline on them. Is this true or can it be resplined as you mentioned? Is there any downside to shortening an axle? A 4.5" backspacing would give it a deeper dish, but would also make the rim stick out more, correct?
Old 07-16-2005, 09:39 PM
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Some Strange axles have splines that are larger in diameter than the axle itself. That's why they cannot be resplined. If you have an axle that has splines as big as the axle diameter getting those shortened works. It's no different than if you bought them that long in the first place. You just have to know whether you can shorten yours or if you have to get new ones. If you are going to narrow an axle, 3" is ideal. Standard 12 bolts either had 31 or 33 splines from most of our sponsors. You would have had to really ask for a 35 spline in most cases since most of us don't push on a car to really need a 35 for the masses.

As far as spacing, you can always use a spacer to push the wheel out a bit if you need to. But, I already know what you will not likely need that. If you move the LCA in that does not necessarily mean the spring needs to move in too. If you crawl in there and look you'll see that the LCA is more outboard of the spring. Simply pushing/offsetting it to the inside of the place that it bolts in gets you an extra inch of tire clearance. You can always go with a smaller diameter spring with the same spring rate as stock if you have to. They are very cheap. Billingsley sells them for around $60 a pair I think.

A .5" difference in backspacing is not going to make your dish look huge. A 15 x 10 on a 5 is still going to have 5" of dish as opposed to 5.5. But, you will see that the tire edge is outside the upper fender line which looks rather ghetto. I'd rather get the 5" BS and then mess with a small spacer if I had to. I had mine with no spacers.

If you look at some pictures that FastBlackTA just posted regarding his 3" narrowed axle and roll cage you'll see how nice everything fits.
Old 07-16-2005, 10:24 PM
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so is the main reason for narrowing the rear to save on rotational mass? if you had a stock width axle couldn't you just change the back spacing so that you could tuck the tires?
Old 07-17-2005, 09:06 AM
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Originally Posted by Dragaholic
Did you have to relocate the springs and LCAs and what size tire are you running?
Didn't relocate anything just moved my lca's in a bit with offset spacers. My tire is a 28x10.50x15.
Old 07-17-2005, 09:45 AM
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Originally Posted by 69vette
so is the main reason for narrowing the rear to save on rotational mass? if you had a stock width axle couldn't you just change the back spacing so that you could tuck the tires?
If all you want is the tuck, then the most BS you can get is 7.5" on a heavy rim and 7" on most of the light weight rims. Compared to what would be the functional equivalent of a 8" BS wheel when you look at your size options on a narrowed axle. An axle that's even 1" shorter will give you the ability to bring the tire in another inch. I think I've already covered the rest.
Old 07-17-2005, 12:09 PM
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Here's a picture of my set-up. Moser 12-bolt, 33 spline, narrowed 1 1/2" on each side. Very little hammering, but the bumb stops have been cut off, and a little welding vice leaving it look like ****. No spacers. 15x10 with 6.5" B/S Boggarts. Tires are Hoosier 30x10.5x15 - had to cut the lower outter fenders to make the 30" fit.

David
Attached Thumbnails Narrowing and backspacing.-bogarts.jpg   Narrowing and backspacing.-hood2.jpg  
Old 07-17-2005, 12:52 PM
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My friend Magnus has 15x10/5.5 backspace/2" narrowed per side with his Strange 12 bolt.

Another buddy Z8's has 15x10/5.0 backspace/2.5 narrowed per side. I'm not sure if he has other mods back there to make that combo work.
Old 07-17-2005, 07:30 PM
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Originally Posted by Pro Stock John
My friend Magnus has 15x10/5.5 backspace/2" narrowed per side with his Strange 12 bolt.

Another buddy Z8's has 15x10/5.0 backspace/2.5 narrowed per side. I'm not sure if he has other mods back there to make that combo work.
We're sick of hearing about your friends stuff. Let's hear about yours.
Old 07-17-2005, 07:31 PM
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So when I order a new set of Bogarts, do I request that they dont weld on a spacer or does that still stay intact? I guess I'll have to call Strange again and ask if the splines are the same diameter as the actual axle or if they are bigger, then I'll know whether or not I have to buy new ones or not. About how much do a set of new axles run? Also, if I do have to buy a new set, what do I ask for, a set of axles 3 inches shorter than the standard size? I checked into Tbyrne's site because that's where I ordered my rear from and they're 33 spline axles. On offsetting the LCAs, is Billingsley the only company that sells them? Are they a completely different LCA or is it just a bracket to relocate the ones you have? I looked on their site, but didnt find any pics or even the part description. I guess I'm gonna order another set of 15x10s with 5" of backspacing. Am I going to run into any issues with the brakes? I'll be removing the parking brake, so I'm not worried about that.

What are you referring to as offset spacers? I'm running BMR bolt in relocation brackets and my Spohn LCAs and on the side that it bolts to the rear end has sperical rod ends and there are no spacers that I know of and there isnt any room to put any to offset it.

Thanks everyone so far for all the help.
Old 07-17-2005, 07:38 PM
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You should make sure that your rims are for the backspacing that you order and that your spacers are separate. The spacers simply sandwich in between the rotor and the wheel. That way you can take them out.

You can probably pull the axles yourself and tell easily. If your thumbnail can grab the leading edge or you can visually see the outer diameter of the splines is greater in diameter than the rest of the axle, then you have to order new. If you order new, 3" shorter than what you have will work. Expect to pay a few hundred bucks for new axles, plus bearings.

You can offset any LCA that has adjustable rod ends on it. If you have a LCA that has bushings, then you need to wing it and either use those or get something else that can be offset. Offsetting the LCA is nothing more than mounting the LCA in the same place that you normally do, except that you have to slide it all the way inboard. Sometimes a 1/4" spacer will help keep the LCA off from the bracket (I'd recommend 1/4 to 1/2" spacer there). There is no bracket, it's nothing more than putting spacers on the bolt to make sure that the LCA lines up in the stock locations offset to the inside of the car. If you have a LCA that has the spacers pressed into the heim joints you need to take those out and replace them with spacers that push it over more in the same spot.
Old 07-17-2005, 07:40 PM
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Originally Posted by 69vette
so is the main reason for narrowing the rear to save on rotational mass? if you had a stock width axle couldn't you just change the back spacing so that you could tuck the tires?
The axles will be stronger also because they're shorter.
Old 07-17-2005, 07:55 PM
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Derty and others....I commend all of you for giving some real good tips...

dragaholic...Give me a call on monday. I can help you with the Bogarts and get things straighted out...spacers and other varies questions...

...most of the guys helped give some pretty good pointers on the board...

...being that you are using our Bogarts, we are offering exclusive pricing for any strange components.

regarding LCA's, we do offer offset LCA's but are not listed on our website. If you already have rod-ended LCA's as Derty stated...it's pretty simple to modify what you have already.

Steve
SJM Mfg, Inc.
Bogart wholesale/distributor
412 508 0634
Old 07-18-2005, 06:38 AM
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Here are some pics of mine:
Fab 9" Narrowed 3" per side
15x10 Alumastars with 5" B.S.
Billingsley Offset Lca's
Changed the rear springs over to 2.5 springs
Minitubbed
29.5x10.5x15



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