Backspacing ponderings...

[Spook50]

Say I want to make my wheelbase wider on my 62. I've never liked how narrow it looks when it's sitting up, and if I end up with an OME kit (or a springover) it's going to look even narrower, and possibly affect stability. I don't want to put full width axles on (well okay actually I do, but that's alot more time and money than I want to spend on something that will still see DD operations). Concerning the strength of the lug studs, what's the minimum backspacing you guys think could be handled if I wanted to run 33" mud terrains? Nothing huge, but certainly big enough to get me anywhere that I'd be wanting to go.

 

[ginericLC]

3.25" is pretty good on a 60. You have a fine line between hitting the outer edge of the rear fender lip and hitting the body (wheel well) right above the frame in the rear. You could drop to 2.5" backspacing but you'd have problems with the outer lip. 3.5" is stock and is pretty good. You'll find finding a 15x8 in lower than 3.5" - 3 5/8" will be sort of tough. Both of those would work fine. Remember it isn't only backspacing that is going to make your rig wider, it is also tire width and rim width.

 

[ntsqd]

Something to keep in mind is a suspension factor called Scrub Radius. Scrub Radius is the difference between where the steering axis intersects the ground and the center of the tire's contact patch. If they are the same point, then there is no scrub radius. If the center of the contact patch is outboard of the steering axis point on the ground, then the rocks the tire hits will have more leverage against the steering system. That works the steering box, the box mounts, the steering damper or ram, the wheel bearings, and all of the steering joints harder than if the contact patch center and steering axis ground point are in the same place. It also can lead to an increased tendency to wander going down the road as it can make the vehicle more sensitive to minor pavement irregularities.

The flip side is that the tire more rolls in turning than it pivots. This combined with the angle of the steering axis (& any Castor) means that turning the steering wheel causes the inside tire to have more load put on it (it's trying to lift that corner of the vehicle) and the outside tire to have some load removed. When you see Comp buggies sawing the steering wheel back and forth they are taking advantage of this to get traction.

 

[Spook50]

Something to keep in mind is a suspension factor called Scrub Radius. Scrub Radius is the difference between where the steering axis intersects the ground and the center of the tire's contact patch. If they are the same point, then there is no scrub radius. If the center of the contact patch is outboard of the steering axis point on the ground, then the rocks the tire hits will have more leverage against the steering system. That works the steering box, the box mounts, the steering damper or ram, the wheel bearings, and all of the steering joints harder than if the contact patch center and steering axis ground point are in the same place. It also can lead to an increased tendency to wander going down the road as it can make the vehicle more sensitive to minor pavement irregularities.

The flip side is that the tire more rolls in turning than it pivots. This combined with the angle of the steering axis (& any Castor) means that turning the steering wheel causes the inside tire to have more load put on it (it's trying to lift that corner of the vehicle) and the outside tire to have some load removed. When you see Comp buggies sawing the steering wheel back and forth they are taking advantage of this to get traction.

Interesting. I hadn't thought of that. So it would seem that the best way to get a wider wheelbase would be to spend the time and money to convert to full width axles and trim the outer lips of the wheel wells to prevent rubbing...

 

[ntsqd]

I'd say that it really depends on what you're trying to do and are willing to live with. The increased wear on the wheel bearings would be a non-issue to a rig that only sees a few thousand miles a year. The ability to alternately load and unload the front tires is highly desired by some folks.

Neither is very desirable to me, but rock crawling isn't my use. Higher speed traversing of the desert is what I am building towards, and for that to work well a lot of scrub radius isn't a good thing.

 

[Spook50]

I'd say that it really depends on what you're trying to do and are willing to live with. The increased wear on the wheel bearings would be a non-issue to a rig that only sees a few thousand miles a year. The ability to alternately load and unload the front tires is highly desired by some folks.

Neither is very desirable to me, but rock crawling isn't my use. Higher speed traversing of the desert is what I am building towards, and for that to work well a lot of scrub radius isn't a good thing.

Rock crawling isn't my goal either. What I want is good stability on road and frequent trail use. It's still a DD, but I take it into deep mud and snow quite often.

 

[Bomar]

Spook

I am trying an angle on this. I am getting 16x8 wheels with a 5 inch backspacing and going to run a 1.5 spacer so that I bring it back to 3.5 but not to put the wheel out to far in the wheel well. I am going to run a 285/75.

I will be putting this setup on this weekend. I think that it should fill out the wheel well but still have the full range of motion.

 

[ntsqd]

Is a 16x8 not available with the 3.5" BS? I'm struggling to understand why the need for a spacer.

FWIW I run that tire size on an GM OE 16x6.75 wheel and they look and fit just about right on a rim of that width. Were it me I'd be looking at using a 7" wide rim.

 

[ginericLC]

4.5" and 5" backspacing is common on 16x8s. About as low as you can find in a 16x8 is 3 5/8" and they are pretty limited. Personally I think you are spending a lot of money for nothing. Buy a 33x10.50 on a 15" rim and run it on a 15x6 stock even or 15x7 rim. I can tell you from my experiences spacers suck on a daily driver. I have them on my 100 only because there aren't wheel options for 5 on 150mm bolt pattern.

As far as Scrub Radius, in an uncut 60 this will not be a real factor.

 

[ntsqd]

What do you mean by "uncut 60"?

 

[Bomar]

I have ran spacers on many different types of cars for many years. I am fine with it.

I wanted a 8 inch wheel not 7.

If they are so great for the tire then why doesn't the tire companies suggest that size?

Only option in 15 for a 33x10.5 is BFG and I didn't want BFG. 16 inch a lot more options.

No option for a black painted steel wheel in a 16x8 with 3.5 or 3.75.

 

[cruiser88]

Just call All pro and get some spacers...many run them without issues

 

[ntsqd]

I have ran spacers on many different types of cars for many years. I am fine with it.

I wanted a 8 inch wheel not 7.

If they are so great for the tire then why doesn't the tire companies suggest that size?

Only option in 15 for a 33x10.5 is BFG and I didn't want BFG. 16 inch a lot more options.

No option for a black painted steel wheel in a 16x8 with 3.5 or 3.75.

Well OK, just seemed like the "stuffing it's ___ with bricks way of killing the cat" to me. I can see needing the spacers if the BS needed isn't available. My pref is to use as small of a spacer as possible. I'd rather go to longer studs than have a bolt-on spacer on something that sees lots of miles. Since you want steel, why not have Stockton or someone like them make the BS that you want? Seems like the total cost would come out less.

I really don't pay much attention to what the mfg says is the recommended rim size. They fit, they work, they don't have a excessively bulged tread indicating a too narrow rim, wtf would I care what the mfg says? I've nearly worn out that set of BFG's on those rims in something on the plus side of 30k of hard Baja & western desert miles. The tread is wearing evenly across the width, I can't ask for much more than that.

All Poo, no thanks!

 

[Bomar]

Stockton wheels are for 4 wheels shipped to me $750 per a quote this week. I love there wheels but so do they.

4 wheels from summit racing $230 and $119 for spacers then I have half my tires paid with the difference in the price between stockton. Plus with 30% off on ebay items I got my tires for $580 shipped for Cooper STT's.

I have ran spacers on cars that are going 150 mph on the track and have no issues with them and I have 10 friends that run them on LC's. I feel comfortable with the spacers.

On the tires 80's have 16x8 and I like the look of the bigger tires on those wheels so that is what I am running with.

I think the terrain that I run my truck in is quite different then what you run in. I will never see sand unless it is a in a river bed.

Also there are some nice Konig 4WD wheels that alot of guys are running in Cali on TTORA, Nice light wheels for $650.

 

[ginericLC]

What do you mean by "uncut 60"?

The fenders aren't cut. You are really limited to size and backspacing because of the fenders. You can't go crazy with backspacing on a 60 unless drop the bump stops quite a bit or cut the fenders.

 

[ginericLC]

I have ran spacers on many different types of cars for many years. I am fine with it.

I wanted a 8 inch wheel not 7.

If they are so great for the tire then why doesn't the tire companies suggest that size?

Only option in 15 for a 33x10.5 is BFG and I didn't want BFG. 16 inch a lot more options.

No option for a black painted steel wheel in a 16x8 with 3.5 or 3.75.

As for spacers, the quality of most of the current offerings suck. If you want to buy made in China POS spacers and put you and your family and other drivers lives at risk so be it.

I misread, I thought you were going to a 255/85/16 and not a 285/75/16. An 8" rim makes more sense than. I still think cost wise you'd be better off sticking with a 15" rim.

Boltons, Stockton, and True Design all offer a black painted steel wheel in 16x8 with 3.5" backspacing. They are expensive. Although I bet the True Design custom wheel is cheaper than the cost of wheels plus the cost of spacers.

 

[GLTHFJ60]

It's not that hard to find wheels with a backspacing of 3.0 or 2.5 inches though, so I don't know why everyone feels it's necessary to buy spacers and 3.5" backspaced wheels. At summit.com, they have 3.0 backspacing steelies in our bolt pattern for $50 a pop, and with a quick phone call, you can get 2.5" backspaced rims for the same price. I'm gonna go this route because the way I look at it, while spacers might be fine for the racetrack, I'm still not sure if I want 12 more bolts to worry about on each axle.

 

[ginericLC]

It's not that hard to find wheels with a backspacing of 3.0 or 2.5 inches though, so I don't know why everyone feels it's necessary to buy spacers and 3.5" backspaced wheels. At summit.com, they have 3.0 backspacing steelies in our bolt pattern for $50 a pop, and with a quick phone call, you can get 2.5" backspaced rims for the same price. I'm gonna go this route because the way I look at it, while spacers might be fine for the racetrack, I'm still not sure if I want 12 more bolts to worry about on each axle.

Not in 16s you aren't going to get a 2.5" backspaced wheel.

 

[GLTHFJ60]

Not in 16s you aren't going to get a 2.5" backspaced wheel.

True true true. I was only thinking about the 15" wheels that I've looked at.

 

[dshock]

I run FJ Cruiser wheels (17") with 1.5" spacers. I was very happy with the quality of the spacers and the fit with these wheels. If I was doing it over, I would do it again.

The scrub radius is very close to stock with my setup.

Regards, Dan