Alignment: Quick Question
Created by: Rosebud
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I actually found my tape measure today and was much surprised to find that 9.4" (or thereabout is exactly at the wheel horizontal centreline. (A008s on 4.5 Minilites).
Who knew...
Cheers, Ian
Who knew...
Cheers, Ian
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Ian: good question about the 9.4".
My guess is that it needs to be high enough to get above any tire distortion from weight bearing but low enough to stay clear of any hub protrusions. somebody writing the manual wanted an exact number (easier to write out!), so they got one. It looks so much more exact than 9" or 9 1/2".
Maybe the bricks they used were nominal 8" and the wood they used was nominal 1.5" which added up to 9.4"
My guess is that it needs to be high enough to get above any tire distortion from weight bearing but low enough to stay clear of any hub protrusions. somebody writing the manual wanted an exact number (easier to write out!), so they got one. It looks so much more exact than 9" or 9 1/2".
Maybe the bricks they used were nominal 8" and the wood they used was nominal 1.5" which added up to 9.4"
.
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Quote:
Originally Posted by Spitz
Quote:
Originally Posted by 1963SV2
Quote:
Originally Posted by Cheleker
Rosebud,
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
.........
..And by the time you chase camber and caster as well .... both front and rear (no rear caster obviously).. and centreline angles .... I just go to the pros... (even if he does run an Escort
Cheers, Ian
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Here you go, Dan:
Same distance across boards out front and same distance across boards behind the wheel = parallel.
I chose 4 ft boards to have enough measurable change if boards were not parallel. This method can easily see divergence of 1/8 inch out of the 48 inch length in my case. Need to be sure not to bump/move the boards but keep them jammed up against the tires so measurement is consistent/reproducible
Again, I chose to make it parallel. A very small change of the steering arm adjustment goes a long ways. I'd say that turning the threads a quarter turn made a whopping difference and smaller incremental adjustments were wiser, then recheck the boards.
Same distance across boards out front and same distance across boards behind the wheel = parallel.
I chose 4 ft boards to have enough measurable change if boards were not parallel. This method can easily see divergence of 1/8 inch out of the 48 inch length in my case. Need to be sure not to bump/move the boards but keep them jammed up against the tires so measurement is consistent/reproducible
Again, I chose to make it parallel. A very small change of the steering arm adjustment goes a long ways. I'd say that turning the threads a quarter turn made a whopping difference and smaller incremental adjustments were wiser, then recheck the boards.
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Quote:
Originally Posted by Spitz
(snip)
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Quote:
Originally Posted by 1963SV2
Quote:
Originally Posted by Cheleker
Rosebud,
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
According to BMC you do an alignment "... at the specified height and diameter and preferably a gauge which measures the angles involved rather than the differences in distances between the wheels in front of and behind the centres. With the car unladen, tyres at the correct pressure and the steering in the straight-ahead position, each wheel should make an angle of 7'30" with the longitudinal axis of the car."
"When measuring distances rather than angles the measurements must be made on a 14 1/2 in. (368.3mm) diameter on the side wall of the tyre at a distance of 9.4 in. (239 mm) above the ground."
Horses mouth as they say...
Cheers, Ian
PS the same annual quotes tyre specs as 5.20-10 tubeless or the optional (radial ply) 145-10 tubeless. I'm just guessing now ... but I'll bet that 14 1/2 in pretty much equates to the widest part of the tyre sidewall..... Rationalising further .. you could drop a vertical from whatever point is the widest on your tyre (front and back) , halve this to get a centre, measure 7 1/4 in back out towards the sidewall marks and Bingo! you have your measuring points for the 1/16th difference.....
Good luck....
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Yes, we could go on forever talking about front toe out, and how the length of the measurement affects the (trapazoid) angle, but as 1963SV2 says, make sure the caster is set right. You can be a little off on the toe out and even the camber, but work hard to get the caster right.
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You're correct of course ... and i'm not surprised Harvey find zero toe acceptable ... considering the amount of flex and flop in even a tight front end.
Not surprised that Hunter's mate found his Mini running true. Toe doesn't usually affect tracking ..but caster has a large effect. We generally set up the case asymmetrically so that the car climbs up the road camber (which all (proper) roads have). Done properly the car will track straight on the highway without the need to steer to keep the car straight.
Cheers, Ian
Not surprised that Hunter's mate found his Mini running true. Toe doesn't usually affect tracking ..but caster has a large effect. We generally set up the case asymmetrically so that the car climbs up the road camber (which all (proper) roads have). Done properly the car will track straight on the highway without the need to steer to keep the car straight.
Cheers, Ian
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Quote:
Originally Posted by 1963SV2
Quote:
Originally Posted by Cheleker
Rosebud,
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
According to BMC you do an alignment "... at the specified height and diameter and preferably a gauge which measures the angles involved rather than the differences in distances between the wheels in front of and behind the centres. With the car unladen, tyres at the correct pressure and the steering in the straight-ahead position, each wheel should make an angle of 7'30" with the longitudinal axis of the car."
"When measuring distances rather than angles the measurements must be made on a 14 1/2 in. (368.3mm) diameter on the side wall of the tyre at a distance of 9.4 in. (239 mm) above the ground."
Horses mouth as they say...
Cheers, Ian
PS the same annual quotes tyre specs as 5.20-10 tubeless or the optional (radial ply) 145-10 tubeless. I'm just guessing now ... but I'll bet that 14 1/2 in pretty much equates to the widest part of the tyre sidewall..... Rationalising further .. you could drop a vertical from whatever point is the widest on your tyre (front and back) , halve this to get a centre, measure 7 1/4 in back out towards the sidewall marks and Bingo! you have your measuring points for the 1/16th difference.....
Good luck....
Geometrical note: It shouldn't be technically necessary to halve the 14.5" to get a centre. If the toe out angles on each wheel are equal (steering straight ahead), your reference height correct, the diverging lines and the cross-measurement lines are parallel (which they should be), then you'd get an Isosceles Trapezoid (US) or Trapesium (UK), where the diverging sides are equal length (14.5") and form equal angles with the base. The result we'd be looking for is the 1/16" difference between the base (forward measurement) and the top (rearward measurement). It wouldn't matter how wide the base is.... sort of proven since there's no mention of varying wheel offset or rim width.
EDIT: Harvey just demonstrated this, and types faster too!
.
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Easier way to do this
lay a straight board alongside the tires on both sides of the car
have the boards up off the concrete a few inches ( I used bricks) so that the board runs alongside and touches enough of the tire in 2 places far enough apart to accurately and truly reflect the way the tires are pointed. Obviously have same air pressure in each tire.
I had the boards 4 ft long. Would not use anything shorter. Outer end is not seen in the photo. Have the ends supported out there in front of the car on bricks, too
Measure the distance from the ends of the two boards -the two ends in front of the car, and the other end of the boars that are just behind the tire. I placed a brick underneath the middle of the car (and out front) so the carpenter's ruler would not sag
I adjusted toe to make mine exactly straight ahead - zero toe. Boards are parallel.
Has been like that since I adjusted in 2002 ( and rechecked several times. ) Car goes perfectly straight and tires wear perfectly even
lay a straight board alongside the tires on both sides of the car
have the boards up off the concrete a few inches ( I used bricks) so that the board runs alongside and touches enough of the tire in 2 places far enough apart to accurately and truly reflect the way the tires are pointed. Obviously have same air pressure in each tire.
I had the boards 4 ft long. Would not use anything shorter. Outer end is not seen in the photo. Have the ends supported out there in front of the car on bricks, too
Measure the distance from the ends of the two boards -the two ends in front of the car, and the other end of the boars that are just behind the tire. I placed a brick underneath the middle of the car (and out front) so the carpenter's ruler would not sag
I adjusted toe to make mine exactly straight ahead - zero toe. Boards are parallel.
Has been like that since I adjusted in 2002 ( and rechecked several times. ) Car goes perfectly straight and tires wear perfectly even
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That's the way you do it. Money for nothing. Chicks for free.
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We did a down & dirty front end toe adjustment in the uneven hotel parking lot at Lake Tahoe at MMW 2011. Measuring across the front & rear of the tires from the same tread groove. Dealing with toe only. In those circumstances, it could not be perfect. But...
The OMS Mini owner emailed me after getting home to Portland, "When I took my hands off the steering wheel on the I5, the Mini ran dead straight."
My response get a laser alignment of toe, camber, caster to get it right.
The OMS Mini owner emailed me after getting home to Portland, "When I took my hands off the steering wheel on the I5, the Mini ran dead straight."
My response get a laser alignment of toe, camber, caster to get it right.
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Quote:
Originally Posted by Cheleker
Rosebud,
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. ......
According to BMC you do an alignment "... at the specified height and diameter and preferably a gauge which measures the angles involved rather than the differences in distances between the wheels in front of and behind the centres. With the car unladen, tyres at the correct pressure and the steering in the straight-ahead position, each wheel should make an angle of 7'30" with the longitudinal axis of the car."
"When measuring distances rather than angles the measurements must be made on a 14 1/2 in. (368.3mm) diameter on the side wall of the tyre at a distance of 9.4 in. (239 mm) above the ground."
Horses mouth as they say...
Cheers, Ian
PS the same annual quotes tyre specs as 5.20-10 tubeless or the optional (radial ply) 145-10 tubeless. I'm just guessing now ... but I'll bet that 14 1/2 in pretty much equates to the widest part of the tyre sidewall..... Rationalising further .. you could drop a vertical from whatever point is the widest on your tyre (front and back) , halve this to get a centre, measure 7 1/4 in back out towards the sidewall marks and Bingo! you have your measuring points for the 1/16th difference.....
Good luck....
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Rosebud,
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. Look in the Suspension and Steering section and look for Front Wheel Alignment. I even found it in one of the earlier generations of Haynes that covered 1959 to 1978 Minis. (That was before they split into two manuals: '59 to '69, and '69 and later.)
As Dan found out, the later Haynes manuals ('69 +) are not as helpful. Regardless of the wheel size, and using the toe-setting equipment I have, I use the same 14.5" measurement centered on the front wheels. That makes the 1/16" toe out no matter what wheel size is being used.
As suggested, you will find the proper toe out setting for 10" rims in the early Haynes manuals. Look in the Suspension and Steering section and look for Front Wheel Alignment. I even found it in one of the earlier generations of Haynes that covered 1959 to 1978 Minis. (That was before they split into two manuals: '59 to '69, and '69 and later.)
As Dan found out, the later Haynes manuals ('69 +) are not as helpful. Regardless of the wheel size, and using the toe-setting equipment I have, I use the same 14.5" measurement centered on the front wheels. That makes the 1/16" toe out no matter what wheel size is being used.
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Quote:
Originally Posted by Rosebud
Quote:
Originally Posted by Cheleker
The 14.5" would be centered on the tire with 7.25" on each side of the center of the wheel.
What it doesn't say is 10", 12" or 13" rims.
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Quote:
Originally Posted by Cheleker
The 14.5" would be centered on the tire with 7.25" on each side of the center of the wheel.
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Quote:
Originally Posted by 1963SV2
Caster does .. and changing the camber changes the caster ..and toe. Set the camber, then caster then toe.
Too much toe out will wear the inner edges. However, it doesn't really make sense to use incorrect settings to take out incorrect wear (getting the balance right is pretty much impossible).. Anyway, once tyres take up a wear "set" its preth much impossible to reverse.
Cheers, Ian
When I get the new tires I'll take my car to my Mini-frendly alignment guy and have him put everything back to spec. Then, I'll take the car home and check everything with my toe plates and create correction factors for furture use.
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I'm not sure where I got the 14.5" spread between the lines first (I've been doing this for decades), but it can be found in the early series of Haynes books, along with the 1/16" front toe out.
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Quote:
Originally Posted by Cheleker
The 14.5" would be centered on the tire with 7.25" on each side of the center of the wheel.
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Quote:
Originally Posted by Rosebud
I've set my toe at .79mm out, half of what Haynes recommends. Originally my toe was set at zero and I've noticed the steering feels a tiny bit sluggish at .79mm out. I may try it at 1.58mm just for reference.
I tried a couple of different camber settings up to 3° negative. I thought I could even out the wear on the inside of the tires and get a little extra milage out of them. At 3° negative the steering was very heavy. I dialed it back to 1.75° and it feels good.
Hmm... I'm using toe plates. It seems to me that the plates are measuring the toe from the center of the wheel to the outside circumference of the wheel; roughly 5" on a 10" wheel. Where does the 14.5" fit in?
I tried a couple of different camber settings up to 3° negative. I thought I could even out the wear on the inside of the tires and get a little extra milage out of them. At 3° negative the steering was very heavy. I dialed it back to 1.75° and it feels good.
Quote:
Originally Posted by Cheleker
For instance, the distance between the two measuring "lines" for 10" wheels is 14.5"
Caster does .. and changing the camber changes the caster ..and toe. Set the camber, then caster then toe.
Too much toe out will wear the inner edges. However, it doesn't really make sense to use incorrect settings to take out incorrect wear (getting the balance right is pretty much impossible).. Anyway, once tyres take up a wear "set" its preth much impossible to reverse.
Cheers, Ian
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