Is 1/2" leaf spring relocation worth the trouble?

[DionR]

Yes! @Craig Burriss proved me wrong on that one for sure!

Wasn't trying to rub it in or anything. And I think technically you were right as your point was they wouldn't work without some work.

I was only posting it for anyone that wanted to see what it might take to run a smaller offset and a bigger tire. It's not a bolt on for sure, that was my only point.

There is another Duster running around with like 315's on 18x10 +25mm wheels on the front (discussion here).

He had to trim things as well, and if you look at some of the other pictures he used massive camber to avoid flaring the fenders.

Just depends on what you are comfortable with.

 

[72bluNblu]

Wasn't trying to rub it in or anything. And I think technically you were right as your point was they wouldn't work without some work.

I was only posting it for anyone that wanted to see what it might take to run a smaller offset and a bigger tire. It's not a bolt on for sure, that was my only point.

There is another Duster running around with like 315's on 18x10 +25mm wheels on the front (discussion here).

He had to trim things as well, and if you look at some of the other pictures he used massive camber to avoid flaring the fenders.

Just depends on what you are comfortable with.

Yeah, that's its own story too. "minimal rubbing" can mean anything, and that's pretty much only a track car from what I gathered.

The other thing is saying he runs 315's in misleading, because his 315's are on 18x10's. That tire is supposed to be on an 18x11, and no smaller than an 18x10.5. So his 315's probably measure more like 295's. I'm pretty sure I can fit 285's as it sits on an 18x10, so that set up isn't nearly as extreme as it sounds.

 

[DionR]

The other thing is saying he runs 315's in misleading, because his 315's are on 18x10's. That tire is supposed to be on an 18x11, and no smaller than an 18x10.5. So his 315's probably measure more like 295's. I'm pretty sure I can fit 285's as it sits on an 18x10, so that set up isn't nearly as extreme as it sounds.

I thought I heard his street setup was a smaller tire, and his track pictures show a black wheel so he certainly has a different combination for that. But the article didn't mention it so I could have that wrong.

Funny thing is, when I was scrolling through the pictures I thought to myself; "those tires don't look any wider than what Blu runs".

 

[72bluNblu]

I thought I heard his street setup was a smaller tire, and his track pictures show a black wheel so he certainly has a different combination for that. But the article didn't mention it so I could have that wrong.

Funny thing is, when I was scrolling through the pictures I thought to myself; "those tires don't look any wider than what Blu runs".

Tire sizing can be funny too! Some 255's and 275's are very close in actual measured specs, I know there used to be some 305's that weren't all that much bigger than 295's. So there are definitely tires out there where the difference in the advertised size and the difference in the actual size aren't the same thing. And that's even comparing the "measured" specs, not accounting for a tire that's been mounted on a wheel that's smaller than the measuring wheel.

 

[DionR]

Tire sizing can be funny too! Some 255's and 275's are very close in actual measured specs, I know there used to be some 305's that weren't all that much bigger than 295's. So there are definitely tires out there where the difference in the advertised size and the difference in the actual size aren't the same thing. And that's even comparing the "measured" specs, not accounting for a tire that's been mounted on a wheel that's smaller than the measuring wheel.

I though the same thing, but could find any specs on the G-Force Rival it looks like he was running at the photoshoot.

This picture does show 315/30R18 on the sidewall, so maybe just his wheels are different for the track.

 

[72bluNblu]

I though the same thing, but could find any specs on the G-Force Rival it looks like he was running at the photoshoot.

This picture does show 315/30R18 on the sidewall, so maybe just his wheels are different for the track.

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So that's actually a pretty wide 315. Compared to the 295/40/18 Falken's I run (on the back) which are listed as 11.8" section and 10.5" tread width those 315's would be .8" and 1.2" wider respectively. But that's what they would be mounted on an 18x11, not an 18x10. I'd bet he's loosing at least a 1/2" of section width because of that.

 

[DionR]

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So that's actually a pretty wide 315. Compared to the 295/40/18 Falken's I run (on the back) which are listed as 11.8" section and 10.5" tread width those 315's would be .8" and 1.2" wider respectively. But that's what they would be mounted on an 18x11, not an 18x10. I'd bet he's loosing at least a 1/2" of section width because of that.

Nice! Your googlefu is much stronger than mine.

Years ago I read "The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10"(5mm)."

Based on that, his section width would be about 12.2". I assume the tread width doesn't change much though?

My benchmark for a tire that exceeds the expected specs is the RT660. A 295/30R18 in brand would be 12.1/10.8. So the section width of the 315 on that 10" tire wouldn't be really any larger, but the tread width would be almost an inch more, assuming tread width doesn't change when the tire is squeezed on a smaller rim.

 

[72bluNblu]

Nice! Your googlefu is much stronger than mine.

Years ago I read "The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10"(5mm)."

Based on that, his section width would be about 12.2". I assume the tread width doesn't change much though?

My benchmark for a tire that exceeds the expected specs is the RT660. A 295/30R18 in brand would be 12.1/10.8. So the section width of the 315 on that 10" tire wouldn't be really any larger, but the tread width would be almost an inch more, assuming tread width doesn't change when the tire is squeezed on a smaller rim.

I don’t want to know how much of TireRacks bandwidth I use up!

So with the section width it depends a lot on the tire geometry, obviously a tire with a short sidewall can’t vary as much from the rim width as a tire with a taller sidewall. Like when I went from 295/35/18’s on the back to 295/40/18’s the section width increased even though the wheels were the same exact 18x10’s.

The same goes for the tread width. If you squeeze a tire on a smaller rim it will bulge the tread, but you can get that back by running a lower tire air pressure. Of course that has limits too, and that will also be effected by the particular tires sidewall height etc.

So generally yeah, the tread width is less effected by the rim width than the section width, but the further you get from the measuring rim width the more the tread width will be effected.

 

[67autocross]

I’m going to run the 10 inch rocket wheels on my dart which “appears” to have a touch more clearances than the Duster style fender…based on my follow the science measurements 10inch is likely at the outer limit for a stockish fender…wider than that you might as well do flairs and step up to a 12 inch wheel…

 

[DionR]

I don’t want to know how much of TireRacks bandwidth I use up!

Ah, now I get it. I use TireRack a whole bunch too, way too much time on there. But I have found they are only useful for current models of tire. The 315 on the Duster above is a Rival, not a Rival S 1.5. No idea how much difference that makes.

I wish they would expose the old catalogs so we could get back to some info on the older models. I understand why, I am sure they feel they wouldn't be safe to use even if someone found a set in a basement. But it sure is needed for research purposes.

Speaking of TireRack, I hate how they changed the spec catalog. Scrolling to the right sucks, I sure miss the vertical catalog arrangement they used to have. Much easy to compare specs.

Maybe it is time to start self capturing the specs of the current tires so later on I can review them.

 

[DionR]

I’m going to run the 10 inch rocket wheels on my dart which “appears” to have a touch more clearances than the Duster style fender…based on my follow the science measurements 10inch is likely at the outer limit for a stockish fender…wider than that you might as well do flairs and step up to a 12 inch wheel…

I would run a 10" wheel front and back in a heartbeat on a no holds build. Mounts some 305/35R18 on all 4 corners and do whatever is needed to make them fit. Kind of a Widebody A-Body.

 

[Mojoe9955]

I ordered the Speedway slider which are advertised as being for Chrysler style leafsprings. In my haste to order them, I failed to read for springs with 1" ID spring eyes, needless to say, A Body springs are a bit smaller than that. I rigged up something in a drill press and with strip of sandpaper held against the secured spinning aluminum bushing, I managed to turn them down to fit. I noticed some of the other brands use nylon bushings, which would have been probably easier to turn down, but I'm not sure about the durability. If I was to do it again, I would try harder to find the correct size bushing or take them to a machine shop and have them done. I was going to use my buddies stand up press, but picked up bench top Delta Shopmaster for $40 off FB which will come in handy when fabbing my relocation brackets.

 

[racerjoe]

I ordered the Speedway slider which are advertised as being for Chrysler style leafsprings. In my haste to order them, I failed to read for springs with 1" ID spring eyes, needless to say, A Body springs are a bit smaller than that. I rigged up something in a drill press and with strip of sandpaper held against the secured spinning aluminum bushing, I managed to turn them down to fit. I noticed some of the other brands use nylon bushings, which would have been probably easier to turn down, but I'm not sure about the durability. If I was to do it again, I would try harder to find the correct size bushing or take them to a machine shop and have them done. I was going to use my buddies stand up press, but picked up bench top Delta Shopmaster for $40 of FB which will come in handy when fabbing my relocation brackets.

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There you go! Sometimes all it takes is a little creativity.

 

[Mojoe9955]

There you go! Sometimes all it takes is a little creativity.

And as a bonus on the way home from picking up the drill press I found this great table with casters and a drawer to store junk in.
Which as you can see I have no shortage of.

 

[Mojoe9955]

Progress update
I'm determined to make it work on my own. So I took some front shackle brackets from a 7.25 rear and with some cutting, welding and grinding was able to come up with something that will on blue tape with give me a 9/16 spring offset.

 

[Mojoe9955]

For some reason there is a hole in the right spot that lines up with the bracket and shackle. I made a washer to take up the space and will try and source a longer bolt to tie it all together.

 

[Mojoe9955]

I have my 1/2 spring offset is essentially complete. I still have to move the perches on the rear.
Utilizing which looks like a 1/2" factory hole thru frame rails, modifying the factory spring perches, a shim, an 8" grade 5 bolt and a bushing for the spring eye to secure the front. Copying member made brackets for the sliders somehow or another the rear spring eye ended up precisely at the end of its slider travel. At first this was not the case as using visual references, I guessed where the sliders mounted on my brackets...they didn't. I moved them forward 1" inch which coinced with the holes in the sliders which actually worked for the better as before I only had 2 bolts securing them to the brackets I now have 4.
I assumed when making the brackets they would be "plumb and square" to the frame torque box where they attached, actually was not. I shimmed the outside of the brackets and once I got them looking a little better and snugged up I drilled a hole in the back of my mounting bracket thru the frame and put another bolt to keep it centered and tightened it all up. This worked out good as I wasn't keen on having 2 bolts holding the slider brackets to the frame. I must have done something right as after all is said and done I'm pretty close to 42" and the springs are just clear of the inside edge of the wheel wells.

 

[mopowers]

Can you get a side shot of the sliders? How are they mounted?

 

[Mojoe9955]

Can you get a side shot of the sliders? How are they mounted?

 

[Mojoe9955]

On the front brackets I just have washers under the bolt head against the frame. In the final configuration I'm going the make a plate to spread some of the load as I'm not comfortable using cheap washers.

 

[mopowers]

Looks really good!

 

[Mojoe9955]

The jury is still out. I have plenty of room height wise using stock 5 leaf springs. There is plenty of room to go wider on the inside, the wheels I have are 285's on 10" wheels with 6.5 backset and are out almost to the edge of the quarters. I'm not sure if going wider is the answer as they'd be close to sticking out. The fronts are perfect. If I can lower the rear some, and trim the 1/4 lip which is pretty wide, I think I'll like it a little more.

 

[racerjoe]

The jury is still out. I have plenty of room height wise using stock 5 leaf springs. There is plenty of room to go wider on the inside, the wheels I have are 285's on 10" wheels with 6.5 backset and are out almost to the edge of the quarters. I'm not sure if going wider is the answer as they'd be close to sticking out. The fronts are perfect. If I can lower the rear some, and trim the 1/4 lip which is pretty wide, I think I'll like it a little more.

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I trimmed the lip on my quarters. I think it's only about 1/2" wide now.

 

[DionR]

The jury is still out. I have plenty of room height wise using stock 5 leaf springs. There is plenty of room to go wider on the inside, the wheels I have are 285's on 10" wheels with 6.5 backset and are out almost to the edge of the quarters. I'm not sure if going wider is the answer as they'd be close to sticking out. The fronts are perfect. If I can lower the rear some, and trim the 1/4 lip which is pretty wide, I think I'll like it a little more.

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So the front is an 18x9 and 275/40 tire? That's what you mentioned earlier in the thread, just curious if that stayed the same.

 

[Mojoe9955]

It is 245/40 on 9" out front. I think we were talking 275 on a 9.5"². I took it for gas and some groceries and it was a little squirrely. It seems like it settled some in the back. I just went out and looked at the fronts and it looks like there is enough room to upsize and I probably will. While I was under there I found a "squirrel" so I definitely won't be driving until then.