Body to tire clearance...

[Zandoz]

What are the opinions on the minimum body to tire clearance necessary with a triangulated 4-link suspension? I've been planning on using wheels with a 2-3" backspace, but I've recently come across a style that I like more, but are 4" backspace. I'm afraid they'd be too close.

 

[Hotrod46]

You could run a 1" wheel spacer to get 3" backspace. I've seen spacers machined from 6061 solid. I don't think I would run cast spacers. Your wheel studs may have to be changed to longer ones.

FWIW - I will probably be using spacers on an OT project I'm working on.

Mike

 

[fluidfloyd]

Bill,

I like 1.0" tire bulge to body clearance for a street car that sees body roll in hard turns or curves. With various tires that don't flex much you could tighten that up some more. Lay it out from a rear view in your cad program and roll the rear end and tires the maximum the shocks will allow and that should give you a good idea of where you need to be. I use to do that on a drafting table but now I'm spoiled!

George

 

[Screaming Metal]

What George said....but a good, general rule of thumb, if you can put your whole hand between the body and the tire, with your palm inside, resting on the sidewall. As long as you can put your hand in there your OK.
Summit & Mark Williams Enterprises (the rear end folks) all have spacers all thickness and sizes....if Summit doesn't have them, MWE I know does....and they aren't that expensive.

 

[Zandoz]

You could run a 1" wheel spacer to get 3" backspace. I've seen spacers machined from 6061 solid. I don't think I would run cast spacers. Your wheel studs may have to be changed to longer ones.

FWIW - I will probably be using spacers on an OT project I'm working on.

Mike

I've thought about spacers (and adapters that would give me more wheel choices), but my past experience with them back in the 70s on VWs was not good. Serious balancing issues. I don't know if the current generation of them are any better.

 

[Zandoz]

Bill,

I like 1.0" tire bulge to body clearance for a street car that sees body roll in hard turns or curves. With various tires that don't flex much you could tighten that up some more. Lay it out from a rear view in your cad program and roll the rear end and tires the maximum the shocks will allow and that should give you a good idea of where you need to be. I use to do that on a drafting table but now I'm spoiled!

George

Yea, the CAD programs have me spoiled to...I don't even know where my old drafting tools are. I've got it all laid out in DraftSight, but the problem I'm having is that the curve of the tire circumference would be right next to the compound curve of the rear corner of the body. I'm having a hard time figuring out where the point of contact would be.

 

[fluidfloyd]

Yea, the CAD programs have me spoiled to...I don't even know where my old drafting tools are. I've got it all laid out in DraftSight, but the problem I'm having is that the curve of the tire circumference would be right next to the compound curve of the rear corner of the body. I'm having a hard time figuring out where the point of contact would be.

I should have clarified my thinking a bit more. Set the 1.0" clearance from the closest part of body interference. Then just move the entire rear axle straight yp and down. Then roll it to it's limit and move it straight up and down again. That should give you a pretty good indication of tire bulge travel in it's worst case position. You could even give yourself 1.5 to 2.0" and still look good. I just really dislike using spacers if at all possible. as for drafting tools...I still have two or three sets. I had two big tables and machines but when I moved to Arkansas I couldn't give them away. Sometimes I wished I had kept one as I do find them therapeutic. Floor space was the big issue as my wife didn't really want one in the living room anymore. Such is life. Besides, I'm in the learning curve of Solidworks and that would be hard to do with pencil and paper.

George

 

[Zandoz]

What George said....but a good, general rule of thumb, if you can put your whole hand between the body and the tire, with your palm inside, resting on the sidewall. As long as you can put your hand in there your OK.
Summit & Mark Williams Enterprises (the rear end folks) all have spacers all thickness and sizes....if Summit doesn't have them, MWE I know does....and they aren't that expensive.

I just checked Summit...$72 a pair.

Looking at my 2D cad drawings, using the section width of the planned tires and the widest point outline of the body, it looks like the closest point of the sidewall would be about 2" from the outline of the body when viewed from the rear. Looking at the top view, the closest point between tire and outline would be about 1 1/2". In reality, the gap would probably be greater because of the compound curve of the body.

 

[Zandoz]

I should have clarified my thinking a bit more. Set the 1.0" clearance from the closest part of body interference. Then just move the entire rear axle straight yp and down. Then roll it to it's limit and move it straight up and down again. That should give you a pretty good indication of tire bulge travel in it's worst case position. You could even give yourself 1.5 to 2.0" and still look good. I just really dislike using spacers if at all possible. as for drafting tools...I still have two or three sets. I had two big tables and machines but when I moved to Arkansas I couldn't give them away. Sometimes I wished I had kept one as I do find them therapeutic. Floor space was the big issue as my wife didn't really want one in the living room anymore. Such is life. Besides, I'm in the learning curve of Solidworks and that would be hard to do with pencil and paper.

George

I'm thinking that before I can do any serious modeling of the articulation, I'll need to figure out the roll center of the suspension. Unfortunately my suspension modeling program was on the computer that died a few months back.

My drafting table went to a good home...my niece is using it for her art work.

 

[Hotrod46]

but my past experience with them back in the 70s on VWs was not good. Serious balancing issues.

That's why I suggested the type that have been machined from solid. The older pieces like you used on the VDub were all cast.

Mike

 

[409T]

I've watched people get their tires nice and close to the body, then light them up at a stop sign, the tires expand, hit the body and you have 31" diameter doughnuts in the fresh paint. Just sayin'.

 

[Zandoz]

That's why I suggested the type that have been machined from solid. The older pieces like you used on the VDub were all cast.

Mike

I checked the ones from Summit...billet aluminum.

 

[Zandoz]

I've watched people get their tires nice and close to the body, then light them up at a stop sign, the tires expand, hit the body and you have 31" diameter doughnuts in the fresh paint. Just sayin'.

That's one aspect that I don't think I have to worry about. I doubt there will be much lighting up with the little V6 that will be powering this thing...LOL

 

[baddawgcustoms]

Speedway has billet aluminium 1/2 inch spacers for $12.99 each. They Cary them up to one inch.

 

[Zandoz]

Speedway has billet aluminium 1/2 inch spacers for $12.99 each. They Cary them up to one inch.

I think Speedway's are all 5 lug....I would need 4 lug...4x4.25 specifically. The more I think about it, the more I think I'd opt for 4-to-5 lug adapters before I'd go with simple spacers. That route would increase my wheel options greatly...but I'd probably just try and track down another pare of Lincoln wires to match the ones I have for the front.

 

[Screaming Metal]

I think Speedway's are all 5 lug....I would need 4 lug...4x4.25 specifically. The more I think about it, the more I think I'd opt for 4-to-5 lug adapters before I'd go with simple spacers. That route would increase my wheel options greatly...but I'd probably just try and track down another pare of Lincoln wires to match the ones I have for the front.

Might consider redrilling your hubs, if you have the meat on the flange....Gab had shown some folks (I think it was either last year or the year before last)how to make their drill jigs, which is really simple, by-the-way.
All you need is some blueing, a pr. of dividers, a calculator or pad w/ paper, if no drill jig.
Alot safe and sturdier than running a wheel adaptor. Then, if you need a shim behind your wheel to space it, just run whatever spacer you need. If they're cnc machined alum. or steel....they're in balance....because they are symmetrical

 

[Screaming Metal]

IF you do decide to do wheel adaptors, do yourself a favor and get quality ones....
http://adaptitusa.com/4-lugto5lugadapters.aspx

Heres a chart by them to find out what you got....
http://adaptitusa.com/referencebook.htm

 

[Zandoz]

Might consider redrilling your hubs, if you have the meat on the flange....Gab had shown some folks (I think it was either last year or the year before last)how to make their drill jigs, which is really simple, by-the-way.
All you need is some blueing, a pr. of dividers, a calculator or pad w/ paper, if no drill jig.
Alot safe and sturdier than running a wheel adaptor. Then, if you need a shim behind your wheel to space it, just run whatever spacer you need. If they're cnc machined alum. or steel....they're in balance....because they are symmetrical

I seiously doubt I'll be attempting any redrilling...to be honest, I don't trust my ability to avoid ruining a rather expensive set of new drilled & slotted rotors, or the old axles for that matter.

IF you do decide to do wheel adaptors, do yourself a favor and get quality ones....
http://adaptitusa.com/4-lugto5lugadapters.aspx

Heres a chart by them to find out what you got....
http://adaptitusa.com/referencebook.htm

Oh yeah! After my past VW adapter nightmares, I'd definitely be looking for quality. At this point I don't think I'll be needing them. The more I play with the 2D CAD drawing, the more I think the 4 bolt wheels that I'm liking will work...and I can always play it safe and get a pair of the Bassett DOT wheels with 2" backspace.

 

[ellis8500]

Bill, these cars have such stiff suspension that I do not believe articulation will be an issue. Mine feels every tiny bump and seam in the road. I do not believe there are any smooth streets in the St. Louis metro area. Some are pretty good but most not.

 

[Zandoz]

Bill, these cars have such stiff suspension that I do not believe articulation will be an issue. Mine feels every tiny bump and seam in the road. I do not believe there are any smooth streets in the St. Louis metro area. Some are pretty good but most not.

Hopefully this one will not be so stiffly sprung. I'm planning on 6" travel coil overs, with 140lb rate springs. If those are too stiff, I'll back off to 125lb rate springs. There's also going to be the option of switching to air springs.

This thing is intended as a cruiser, and to be as comfortable as possible.