Wheel track vs. Axle Track

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newyorkkopter
newyorkkopter
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Joined: 16 Aug 2010, 23:45

Wheel track vs. Axle Track

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Hi guys, I've been doing some research on wheel track vs axle track

I wanted know, is the net effect of increased wheel track the same as increased axle track?

Like for example,
A normal E46 M3 has 60'' rear tracks (measured hub to hub)

But if I put lower offset wheels on the car, the wheel track would get wider(tires would be further apart), while the axle track would stay the same

Now my question is would the net effect of mounting the wheels further apart be the same as increasing the axle(hub to hub) track?

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Sebp
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Joined: 09 Mar 2010, 22:52
Location: Surrounded

Re: Wheel track vs. Axle Track

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It would not be the same. For both, front and rear axles you have to consider your suspension geometry.
If you only change your offset between rim and wheel hub your original suspension setup stays the same. For wider "axle track" you would have to install larger wishbones which would change the wheel hubs' travel radii.
Additionally in the front you have to consider the effect on your steering angle.
No smartphone was involved in creating this message.

newyorkkopter
newyorkkopter
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Joined: 16 Aug 2010, 23:45

Re: Wheel track vs. Axle Track

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that makes sense, but can you explain how it would be different?

Like typically, a wider axle track produces less roll,

so would a wider wheel track produce less roll as well?

(I mean in a general sense; every car is different)

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Ciro Pabón
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Joined: 11 May 2005, 00:31

Re: Wheel track vs. Axle Track

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Hi, newyorkkopter. I'm kind of firing from the hip here, but I'd say no.

Actually, trying to get the benefits of a wider track from wider/expanded/modified rims is one of the marks of the ricer beast, if you follow my drift. Along with fake engine noises, large wings, body kits and decals from other cars...

If you don't mind having no suspension, then wider/expanded tyres are the bees knees
Image

There are several disadvantages.

Depending on how you increase your track, sometimes wheel or wishbones bearings would be subject to greater forces.

Sometimes, tyres would bump into the body.

Sometimes people try to compensate with negative camber (tyres would look like this: "/\"), making things worse.

Another thing is more unsuspended mass, heavier steering, a bit less acceleration because of the added rotational mass (if the extensions are fixed to the rims, clearly), changes in balance of under/oversteering, etcetera, etcetera.

I've seen (and given my condolences to) cars that can't even turn the steering wheel fully in either direction without the tyres rubbing.

However, yes, you'd have less lateral roll, specially if the body hits the tyres.

Do... not... steer... this... car!
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Ciro

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Wheel track vs. Axle Track

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The main problem is that on the front steering axle you are moving the position of the kingpin inclination angle relative to the centre of the tyre footprint.
This completely alters the steering geometry.
If you fit wider wheels they need to be wider by an equal amount either side of the wheel centre.
If they are not (usually because of clearance issues) you should change the steering and suspension geometry and rate.
Cars designed for low speed drifting are not really worth comparing for road or proper competition use.
Neither are low speed show machines.

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Ciro Pabón
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Joined: 11 May 2005, 00:31

Re: Wheel track vs. Axle Track

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Well, yes, auto, but you forgot to say it can be done anyway.

As I say sometimes to my kids: "every squirrel is a flying squirrel if you throw it hard enough"...
Ciro

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Wheel track vs. Axle Track

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A question very easy to ask but as you see quite faceted answers and rightly so .In finding good setups one quite often has to compromise as your aim surely is maximising grip -but this does not count for anything if one end of the car is lacking grip then and you simply cannot exploit all the potential which might be there.
So widening track or axle width may or may not help .And sure it is very much a question just where you will try to run the thing and how stiff the competition is ....
I had more than once to do something completely "wrong" to make a car handle "right" and be quick on the day.sometimes facts of life ,circumstances and whathave you might drive you to mount a set of wider rims on the car even though it might be a much better solution to have a wider axle...but if you can have the first and gain a tenth instead of two for the better solution but you cannot afford to buy a 10K € Upgrade and you were winning races anyways with the old setup....it is rather obvious what a sensible guy would do... :roll:

and let´s face it-if that tenth is not bothering you in the first place -only the engineering orgasm to have it done "right" will bring back your peace of mind...if you don´t understand what I wrote -just mount the wider rims.

newyorkkopter
newyorkkopter
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Joined: 16 Aug 2010, 23:45

Re: Wheel track vs. Axle Track

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Thanks guys for all your input

Makes sense, it is definitely more complex than just wider is better.
A wider wheel track to compensate for a narrow axle track is abit rice, as well as it heavily alters the steering geometry of the car as well

So basically what I'm getting from all this is that at end of the day it really depends on what you as a individual are looking for and that this is a much more complex topic than I presumed