Front end wider after disc brake conversion...

[ENDLIFE]

One late night of work a friend and his rig showed up for a disc brake conversion, and the case of Guinness made the job worth it. For anyone that has done this conversion knows it's very easy and straight forward. This morning I got a call of a problem but not a problem, he explained that the front end looked wider then the rear, but it drives perfect. Then I had to look at my rig, there it was, not by much, but my front end looked wider, as well.
I have a method for straightening front ends on Broncos and yes some Jeeps, it involves a couple of holders I machined to hold a laser in each bump stop hole, and then I center the axle to the frame. Another awesome CB member told me he had to de a rear disc conversion to get things to square up, and now comes my question....
Has anyone else had this problem, am I doing something wrong?????

 

[TwoDalesDad]

I have to go.....i now have the perfect excuse to add the disc's on back.....i will let her think that......the bronco won't be right...unless the wheels are even....ha!

 

[TheGanzman]

The '74 I just bought has discs front and rear; I noticed that even on this one, the front "track" appears wider - I'll measure it when I get it here. There's not anything really wrong or dangerous about that; actually, it's a LOT more common than you think! You could always put spacers on the rear in-between the hubs and wheels...

 

[broncodriver99]

Mine may be slightly wider, but pretty much every vehicle has a wider front track. I am not concerned about it.

 

[Timmy390]

My 74 had a wider front track before the disc conversion.....I found this when trying to set "toe" the NASCAR way with a string then with a long section of flat stock. Adding the disc's didn't increase it that I know of.....

Tim

 

[broncnaz]

A lot of vehicles do have wider front track widths than rear track widths. There are some handling traits that apply to the differance. I cant remember exactly what.

After I did a ford front disc swap on my 73 I noticed the differance But I believe the ford swap increases the track by about 1/2" Not sure how much or if the gm swap also does this.

 

[DuctTape]

A lot of vehicles do have wider front track widths than rear track widths. There are some handling traits that apply to the differance. I cant remember exactly what.

After I did a ford front disc swap on my 73 I noticed the differance But I believe the ford swap increases the track by about 1/2" Not sure how much or if the gm swap also does this.

Hmmm. Do you know what would happen to handling if rear is wider than front?

I have a d44 up front but PO swapped in a d60 from an f150 and rear is 1-2" wider. Not happy with my road handling characteristics and wondering if that is part of it.

 

[asinor]

Hmmm. Do you know what would happen to handling if rear is wider than front?

I have a d44 up front but PO swapped in a d60 from an f150 and rear is 1-2" wider. Not happy with my road handling characteristics and wondering if that is part of it.

It could be. A wider front track than rear track decreases the weight transfer from the inside rear to outside front. For an extreme example, compare the handling of a traditional 3 wheeler (very narrow front track vs. wide rear track) vs a Can Am Spyder or T-Rex (wide front track vs. very narrow rear track). The 3 Wheeler wants to tip in a corner, while the Sypder does not. A narrower front track will want to oversteer.

My stock D30 setup appears to be 1/2 to 1" wider in the front.

 

[bmc69]

My stock D30 setup appears to be 1/2 to 1" wider in the front.

FWIW, I just measured a few that are sitting around the shop area:

Narrowed '76 F-150 D44 and stock 9" rear in a '69: Front is 2" wider than rear

Stock '76 EB 44 and 9": Same thing...front 2" wider than the rear

Stock '68 D30 and 9": Front 1" wider than the rear.

 

[DuctTape]

It could be. A wider front track than rear track decreases the weight transfer from the inside rear to outside front. For an extreme example, compare the handling of a traditional 3 wheeler (very narrow front track vs. wide rear track) vs a Can Am Spyder or T-Rex (wide front track vs. very narrow rear track). The 3 Wheeler wants to tip in a corner, while the Sypder does not. A narrower front track will want to oversteer.

My stock D30 setup appears to be 1/2 to 1" wider in the front.

Sooo confused but thanks. Steering geometry should be easy but for some reason I always tie myself in knots when I try to figure it out.

 

[Steve83]

AFAIK, Ford trucks have always had a wider front track, but this says otherwise:



[QUOTE='68 Bronco Brochure]Wide 57" track for both front and rear axles[/QUOTE]

Maybe that's just marketing jargon meaning it's wider than vehicles with narrower tracks, and they're not being specific about the F/R track difference.

 

[rguest3]

I have had about 10 of these things and all of them have a wider front end. Drums or Disc.

I usually put a 1" spacer on the rear to compensate. Looks better to me.

 

[TheGanzman]

I have had about 10 of these things and all of them have a wider front end. Drums or Disc.

I usually put a 1" spacer on the rear to compensate. Looks better to me.

Do you subsequently notice any difference in driving/steering/handling?

 

[broncnaz]

For the most part you shouldnt see much differance in handling unless your racing or doing high speed cornering neither of which the bronco was designed for. Cant see a wider rear being all that detremental to handling after all look at dually trucks they handle fine.

 

[rguest3]

No, no difference is steering response. Nothing negative at all.

 

[MyOriginal66]

I've been told disks push the wheels about 1/4" out further per side than drums. But that's just what I've been told%)

 

[RODRIG3911]

I noticed on this page from TBP that the linkage for a 66-75 with DRUMS is 48" and the 76-77 DISK is 50". I wonder if that is just for the original disk and not when we do the aftermarket conversions??

http://www.tomsbroncoparts.com/category/66-77-bronco-steering-linkage

 

[broncodriver99]

I noticed on this page from TBP that the linkage for a 66-75 with DRUMS is 48" and the 76-77 DISK is 50". I wonder if that is just for the original disk and not when we do the aftermarket conversions??

http://www.tomsbroncoparts.com/category/66-77-bronco-steering-linkage

The 76-77 Disc knuckles are different. It's not so much that the wheel mounting surface is wider but the attaching point for the tie rods on the 76-77 knuckles are farther outboard(has to do with the inverted y linkage). That is why some wheels that fit 66-75's will rub the tie rods on a 76-77 disc front end.

 

[Steve83]

...the attaching point for the tie rods on the 76-77 knuckles are farther outboard...

So that means they adjusted the Ackerman angle on those trucks.