Drop spindles and increased track width..
 

Attachment 1499002

I have a 64 GMC 1000 that I purchased this summer. The previous owner converted the front to disc with 2.5" McGaughys drop spindles. He told me that this conversion added what seemed like " a few" inches to the track width.

This week I finally received my Mob Steel steelies and mounted them up. I also changed out the front springs to a CPP 3" drop spring. This achieved tucking the rubber into the fender well, but with the backspacing I ordered there is rubbing during turning/compression.

I'm trying to see if anyone knows if there are other drop spindles that maintain the stock track width or even narrow it a bit. I want to end up with a Porterbuilt stage 2 set up which can be customized to fit my track width, but for now, while I'm broke, I'm trying to find the best way to solve this issue.

I see my options as of now are:
-Put the 1" drop spring back in that didn't cause any issue, but the stance is t right
Or
-Find a set of spindles that can narrow the track width (best option if it is available)
And/or
-Roll the fender lip tight to see if it gets me enough room (don't think it will though)
Or
-Find $2000 to buy the PB Fab stage 2 front set up (wife will shoot me)

Let me know what you guys think. Thanks for your time in advance.

Re: Drop spindles and increased track width..
 

If I'm not mistaken, the CPP modular drop spindles do not affect track width.

Re: Drop spindles and increased track width..
 

Run a shorter front tire?

Re: Drop spindles and increased track width..
 

I also have the McGaughys drop spindle disc brake to install on my 64, what front back spacing dud you order?

Re: Drop spindles and increased track width..
 

Your tires look really tall.
What size are they?
How did you determine what backspace to order on your Mobsteel wheels?
Seems like you just need more backspacing to suck the wheels in.

Re: Drop spindles and increased track width..
 

I dont think that has ever been confirmed by anyone,... even CPP.
No exact dimension compared to:
1) drum brake spindles
2) oem disc brake spindle
3) standard 2.5" or 3" drop spindle.
The CPP Modular spindle is narrower,... but by how much has never been documented.

Re: Drop spindles and increased track width..
 

I measured for backspacing using all the resources on this site. It was my first time doing it, but did get confirmation from my tire guy. More backspacing would definitely fix the issue, but buying more wheels is not an option. The wheels are 20x9 with 5.5" BS. Tires are Toyo Proxi ST II, 275-45-20. I was going off of PB Fab, and wanting to end at a dropmember. The figures I referenced talked of a 30" tall tire setup. These measure out at 29.7". When everything was mounted, I had a 2.5" drop spindle and 1.5" drop springs, and nothing rubbed. But stance wise, it didn't look right to me. There was a 1" gap between the front fender lip and the rubber. I changed to springs to 3" drop, and all went bad. I would love to find a drop spindle that would retain the stock (or narrower) track width but for now I'm going to put the longer springs back in so I can get back to driving it. I'm at the firehouse today, but tomorrow I am going to pull some numbers on my track width to compare to stock, and other members who have stock suspension with different drop spindles.

Easiest fix would have been more back spacing and/or a 275/40/20. I went back and forth a hundred times on both of these decisions. Both were new to me and a bit daunting. With this being a pretty big purchase for me, I definitely put much thought and effort into it. But didn't account for the additional drop that I planned. I appreciate all assistance in correcting this issue. Thanks guys.

Re: Drop spindles and increased track width..
 

If the tires are the same front & back then you'll have a spare set for the rear & won't have to worry about smoking the rear tires since you have a spare set lol

Re: Drop spindles and increased track width..
 

I like your thinking! Just have to see if I can sell that to the wife. Ha ha.

Re: Drop spindles and increased track width..
 

I would run a 20x8 (5.5" backspace) with a 245/40-20 tire up front.
A 9" rim and a 275/45 is huge up front on a low truck.

If you move that big tire in with a narrower drop spindle, will you rub on the inner fender?

Re: Drop spindles and increased track width..
 

I'm just going by what the sales rep at CPP told me??

Re: Drop spindles and increased track width..
 

Definitely would be a safer choice in hind sight. When I get home from work tomorrow, I'm going to do more measuring. Maybe I just need to find someone with a set of 20x8 5.5bs mob steels on their truck who wants a wider rear setup and we can do a two wheel swap.
Hopefully I can get it figured out without needing to do that, but nothing is ever off the table. Thanks again for all the ideas. I'm going to call some different manufactures tomorrow and ask some questions. Thanks, Brandon

Re: Drop spindles and increased track width..
 

Attachment 1499119

Here is where I was at after just installing the wheel/tire set up, with the 1 1/2" drop springs. I didn't have any rub issues on the 1 1/2 hour drive home. Just for reference.

Re: Drop spindles and increased track width..
 

Are your rear wheels & tires the same size as the front?

Re: Drop spindles and increased track width..
 

Yes. They are all the same and the back has 1" wheel spacers.

Re: Drop spindles and increased track width..
 

So you could have used a 20x9 with 4.5" backspace on the rear?
Just trying to get my numbers straight for the 63-66 trucks.
What year rearend is in the truck?

Re: Drop spindles and increased track width..
 

The stance is not bad on the taller spring. You have got a lot of tire on there so you may have to live with the taller spring till you can get a drop member under it with the narrow arms on it.
Jimmy

Re: Drop spindles and increased track width..
 

So it looks like 20x8 4.5 bs is the way to go for lowered springs or bagged stock arms and rear end.

Re: Drop spindles and increased track width..
 

Everyone should measure their own trucks.
Too many differences and mods that might not be mentioned in a thread.

Re: Drop spindles and increased track width..
 

The rear is the stock 64 10 bolt. 20x9 with 4.5bs would put it right where I'm at. The back clears fine and is in good shape. I was trying to keep the wheel/tires all the same size for rotation purposes. I appreciate your info and have learned a lot from your posts. Thanks Keith.

Re: Drop spindles and increased track width..
 

If the Porterbuilt setup is made for a 30” tire and that’s what you want to end up with in the long run it would probably be best just to throw the 1.5” drop springs in and save the money towards what you really want. You won’t have the cool rake but it still looks really good. I think you would have to spend several hundred bucks towards a solution to a problem that is basically temporary if your tire and wheel will work with the PB setup. :chevy:

All that said. I agree with lowlife99.
30" tires a pretty big on a lowered truck.

Re: Drop spindles and increased track width..
 

Another vote for different back spacing on the wheels. I replaced my front end with one for a 2003 Lincoln Towncar (Ford Panther front end) and went thru 3 sets of wheels before I got the back spacing right. I also went thru two sets of springs. But now it looks good. Nothing spending money won't fix. But once you get it, you have it. :)

Re: Drop spindles and increased track width..
 

I'll be home in a couple hours, and then I'll start making some calls and doing some measurements on my current track width. I'll need to find out what the stock track width is for a 1964 GMC 1000. I'm sure it is on here somewhere. Then the taller springs will go back in, and see where things go from there. Now that PB's new site is up, I double checked the tire height numbers and they reference a 29" tall tire when quoting ground clearance levels with the different drop kits. I was going to call them and get their input also. Thanks everyone for the assistance. B

Re: Drop spindles and increased track width..
 

Project delayed for a day due to needs around our small farm. I'll let everyone know what I find hopefully tomorrow evening.

Re: Drop spindles and increased track width..
 

I made some calls this morning and here is what I've found so far. All information below was from the tech support line at each individual company:

McGaughys (pronounced McGoy i learned)
-their 2 1/2" drop spindle adds +3/8" to each side for a total of +3/4" added to overall track width
CPP
-their modular 2 1/2" drop spindle does not change the stock drum brake track width you had prior to converting to their spindles and disc brakes. They said their may be "minor" differences based on individual truck, but should not be a measurable difference.

Called Porter Built and left a message. More info to come .