Wheel spacers: when are they to much?

[1200 Hobos]

Massive spacer on the Hypermax evo @ 1:42. That's like, 2 inches?

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[Wendys or Bust]

hell yes, that bitch is huge! At least its machined to fit the wheel hub flush. I also wouldn't doubt they added it for brake clearance as well.

[Johnny Mac]

Originally Posted by TunerN00b

The lateral length from the balljoint to the center of the tire's contact patch, is part of the LCA length, as far as leverage is concerned, and does affect the motion ratio.

At least, that's how I've read it, and it makes sense to me.

You are correct. I wrote an article for Honda Tuning magazine on "Wheel Offset" that discusses the bearing issue, the reduced wheel rate for less positive offset, scrub radius, ect. and it is available here:

http://www.hondatuningmagazine.com/t...eel/index.html

If you have any questions about this, please do not hesitate to add them to this discussion.

[DB2-R81]

For solo II, track width does play a large role in the optimal driving line and there is a large trade off with the wider you travel around the cones.

[beanbag]

Originally Posted by TunerN00b

The lateral length from the balljoint to the center of the tire's contact patch, is part of the LCA length, as far as leverage is concerned,

No it is not, because there is a joint at the end of the LCA, namely the LBJ. Levers have a pivot in the middle, but not a joint that can flex. This is a linkage mechanism, and not a simple lever.

Consider what happens if you have a really thick spacer, and you have these different suspension geometries:

A) a really strong camber curve - a small deflection of the suspension causes the top of the wheel to flop inwards.

b) a parallelogram linkage where the camber is a constant 0.

c) opposite of A), where a small deflection of the suspension causes the top of the wheel to flop outwards.

Again, the effects of a wheel spacer on effective wheel rate comes thru the camber curve, NOT the increase in lever length of the LCA.

[Jaker]

I think you're failing to realise that the location of the LBJ does not factor into the lever arm length when looking at the wheel rate. The lower control arm does not bend at the LBJ. The effective length of the lower control arm in an OEM configuration is the total length from the inner pivot point at the chassis to the center of the contact patch of the tire. Not the inner pivot point to the LBJ. If you move the contact patch further out (wheel spacers) the effective length of the arm increases which alters the wheel rate.

[577HondaPrelude]

1) On a car with an upper control arm, wheel spacers will NOT effect the wheel rate
2) On a car with a strut (no upper control arm), wheel spacers will effect the wheel rate.

[DB2-R81]

Originally Posted by Jaker

I think you're failing to realise that the location of the LBJ does not factor into the lever arm length when looking at the wheel rate. The lower control arm does not bend at the LBJ. The effective length of the lower control arm in an OEM configuration is the total length from the inner pivot point at the chassis to the center of the contact patch of the tire. Not the inner pivot point to the LBJ. If you move the contact patch further out (wheel spacers) the effective length of the arm increases which alters the wheel rate.

Thank you, read and think about what Jaker wrote again. Upper control arm irrelevant.

[slammed_93_hatch]

while i know you can find anything on the net here is one of the first images that popped up on google image search.

http://www.miracerros.com/mustang/t_wheel_rate.gif


I don't see how it matters between strut or DBW/multilink.

You are still moving the center of the tires contact patch further away, increases the total distance. Like jaker said the LBJ is a solid attachment point.

[beanbag]

I tried simply saying it. Then I tried giving examples. Now I have no choice but to be a pedantic ass. Look at these two diagrams, which spells out how the UCA DOES matter in terms of wheel spacers. Because it sets the camber curve.



Now watch what happens when you take away the camber curve.



And yes, there are some approximations.

[Viorent GRIP!]

Originally Posted by essex

What about Moog bearings?

Does anyone have a ntn or koyo bearing number for a 89 crx?

Koyo Front wheel bearing (L/R) - 88-91 Civic / CRX
PN# 44300 SB2 966

Hit up Jeff @ Proparts USA he's got them.

[Justin Jones]

Originally Posted by Jaker

I think you're failing to realise that the location of the LBJ does not factor into the lever arm length when looking at the wheel rate. The lower control arm does not bend at the LBJ. The effective length of the lower control arm in an OEM configuration is the total length from the inner pivot point at the chassis to the center of the contact patch of the tire. Not the inner pivot point to the LBJ. If you move the contact patch further out (wheel spacers) the effective length of the arm increases which alters the wheel rate.

Pretty sure I agree with this.

[Wai]

I didn't check back this thread until now, didn't know it got into more discussions.

Originally Posted by beanbag

I think it only softens the suspension very very slightly due to camber curve, not motion ratio.

The OP drives an EP with strut, altho I don't have any detail info on how everything is mounted, I would say that the spacer would affect the motion ratio.

Originally Posted by beanbag

No it is not, because there is a joint at the end of the LCA, namely the LBJ. Levers have a pivot in the middle, but not a joint that can flex. This is a linkage mechanism, and not a simple lever.

For double wishbone, I would agree with you that spacers don't have much affect on the motion ratio.

For those who can't visualize it, try drawing simple free body diagrams. For DWB, spacers would increase the compression and tension on the UCA and LCA due to the longer moment arm, but the vertical forces that get transferred to the hub surface would not change; and hence, the force being applied to the spring would not change.

In simpler words, the additional force resulted from the thicker spacers is being resovled as a couple (tension/compression) and is taken by the control arms. The spring wouldn't see any of that.

I hope I get the point across, and of course I would welcome any corrections if I were wrong.

[beanbag]

A strut suspension generally has even less camber change than a double wishbone, so the effects of a wheel spacer would be even less. As you say, all that "extra leverage" from the wheel spacer will go into side loading the shock, not compressing the spring.