Bowed front tires (\/)

Suspension, steering, brakes, wheels & tires

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sb4boys
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Bowed front tires (\/)

Post by sb4boys »

I replaced all the bushings, tie rods and coil springs on the front suspension of my 68 F-100 and the tires are now bowed in (\/). I adjusted the tie rods but get the same results. The tires were straight before I changed everything. Is there something else I need to adjust to fix the issue?
71Fe2O3
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Re: Bowed front tires (\/)

Post by 71Fe2O3 »

Do they appear this way when looking at them from the front of the truck?

If so, this is a camber issue. As far as I know, camber is adjusted by bending the I-beams (assuming you have a 2WD truck with stock suspension), which you likely can't do at home, nor should you need to if you are maintaining stock height. There are threads on here about owners installing longer springs to increase the height of the front end-this requires brackets to lower the other end of the I-beams.
The I-beams are attached to the frame at the end opposite the tire, so you can only influence camber by lengthening or shortening the wheel end of the suspension. Your description suggests that you lengthened the wheel end. Perhaps your springs are too long or not seated properly.

If they appear that way when looking at them from underneath, your problem is with toe, and can be changed by adjusting the length of the tie rods. You can use a tape measure to get this close. Measure the distance between the fronts of the front tires and the backs of the front tires and adjust the tie rods until the fronts are slightly closer together than the backs (toe in), probably between 1/8" and 1/4".
A knowledgeable mechanic with an alignment rack can do a better job, but this will get you close enough to be able to drive the truck.
Fred

1970 F100 4WD short bed, 360 engine, very rusty plow and yard truck

1971 F100 2WD long bed, 302 engine, on the road

1968 F100 2WD long bed, 360 engine, stripping for parts
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1972hiboy
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Re: Bowed front tires (\/)

Post by 1972hiboy »

I think a couple trips to the alignment shop are in order. First trip to get you safe to drive. Then drive the truck around for a couple weeks , let the front end and springs settle a bit then align again. New coils will tend to do that. ride higher at first then settle down a bit. this is if the camber is the concern. if you are talking about toe then that adjustment is in the steering linkages.
Rich
1973 f350 super c/s 460/c6 22k orig miles
1972 f350 srw crewcab special 390
1972 f250 4x4 sport custom 390fe Red
1972 f250 4x4 custom 360 FE " Ranger Ric"
1972 f250 4x4 custom 84k og miles 390
1971 f250 4x4 sport custom 56k og miles. 360
1970 f250 4x4 428 fe hp60 205 d60
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daveford72
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Re: Bowed front tires (\/)

Post by daveford72 »

Did you check the height of your new coil springs? My 1967 f350 is like that. The prevs owner put in very heavy ones that are a little too tall.
sb4boys
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Re: Bowed front tires (\/)

Post by sb4boys »

All,

Thanks for all the feedback. The coil springs were the same size, but the truck is not being driven at this time, and the springs have not had a chance to settle. This could be some of the cause. Looking at the truck from the front the tires do appear in a "V" pattern. The tires were straight before I replaced all the bushings and tie rods. Would these replacements cause the camber to change?
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Re: Bowed front tires (\/)

Post by Ohiotinkerer »

If possible try rolling it back and forth maybe 10 feet or so and see if that helps it any - if the bottom of the tire is in further than top it could be from just being up off the ground. I put new springs in my 68 and when i let it down mine were like that.....just the nature of twin I beam suspension. Once I drove it everything settled in........as far as the toe from replacing the tie rods 1/8 inch out on the front will do you fine until you get it aligned........
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1968 F100 2wd - Rangoon Red - 360 w/T18 - power steering and brakes
1997 Honda CBR 900RR
71Fe2O3
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Re: Bowed front tires (\/)

Post by 71Fe2O3 »

In order to roll in a straight line, steer properly, and minimize tire wear, the front end of a vehicle must be adjusted in the three dimensions known as caster, camber, and toe, which are generally expressed as angles.
The caster angle is a measurement of the steering axis and affects how the vehicle steers and straightens out after a turn. Think about a motorcycle with a vertical fork relative to one that is steeply raked. I don't think you can modify caster on these trucks.
The camber angle is a measurement of the relationship between the vertical axis of the wheel and the vertical axis of the vehicle. Positive camber is when the top of the wheel tilts away from the vehicle, and negative camber is when the top of the wheel tilts toward the vehicle. On a vehicle with I-beam suspension, the length of the springs would have a direct affect on the camber angle.
The toe angle is a measure of the relationship between the wheels and the longitudinal axis of the vehicle (the front and rear edges of the wheels relative to the frame), and is adjusted by changing the lengths of the tie rods.

The problem you described is a change in camber angle. Nothing you did should have affected caster, and the tie rods affect the toe angle but not camber. I don't think that changing bushings would affect alignment. It seems most likely caused by the springs, either because they are too long, as daveford suggested, or because they need to settle in, as 1972hiboy claimed.

You may also have changed your toe angle when you changed the tie rod ends, but this may not be visible. Drive the truck a bit, slowly on back roads at first if you can, see how it feels-you may need to adjust the toe angle or have it done. If your springs are the stock length, the camber angle should come back to normal.
Fred

1970 F100 4WD short bed, 360 engine, very rusty plow and yard truck

1971 F100 2WD long bed, 302 engine, on the road

1968 F100 2WD long bed, 360 engine, stripping for parts
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Re: Bowed front tires (\/)

Post by ultraranger »

After the bushing change, did you tighten the bolts with the suspension in droop or, did you tighten the bolts with the tires back on the ground and the suspension loaded with the weight of the truck on them?

Make sure the tail of the upper ends of the coil springs are seated into the buckets. If they're rotated out of position, it's going to push the stance of the truck higher in the front.
Steve

1969 SWB F100 Ranger. 240-6, C-4, 9" N-case 31-spline Traction-Lok w/3.50 gears.

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