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PostPosted: Wed May 21, 2008 10:15 pm 
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As the title says... I'm trying to work out what you'd classify mini front suspension as. Twin A-arm, but not... :?

Does it add camber as your wheel goes up? I want to get an understanding of the characteristics of the front suspension so your help is much appreciated :)


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PostPosted: Wed May 21, 2008 10:35 pm 
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I think the most appropriate geometry would be as you said, double wishbone (a-arm). On the Mini, camber decreases with increased deflection (in other words, negative camber increases as you lower the car).

I think with equal-length upper and lower arms the camber remains static, but the track width changes with deflection.. but since the Mini has longer bottom arms the camber decreases with compression.

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PostPosted: Wed May 21, 2008 10:59 pm 
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Awesome. That was how I suspected/hoped it worked :)

What's the deal with the tie rod bars? With an A-arm setup both ends are rose-jointed, where with the mini the lower arm is made up of a lower control arm ( I'll be using rose-jointed arms ) and a tie rod bar which doesn't exactly pivot as such because it's bushed... :?

I guess what I'm asking is why are the tie rod bars bushed instead of pivoting like what KAD has done ---

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Just in case your wondering why I'm so interested, I'm planning on using mini front suspension in the rear :wink:


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PostPosted: Wed May 21, 2008 11:36 pm 
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Dont quote me, but I thought the rose joints were not road legal :?:


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PostPosted: Wed May 21, 2008 11:42 pm 
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jasonf wrote:
Dont quote me, but I thought the rose joints were not road legal :?:


Andrew doesn't seem to have a problem getting them engineered... :? :D


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PostPosted: Wed May 21, 2008 11:46 pm 
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no probs then.....is there an awd on the horizon then :wink:


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PostPosted: Wed May 21, 2008 11:48 pm 
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jasonf wrote:
no probs then.....is there an awd on the horizon then :wink:


Mid-mount RWD in the works 8)


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PostPosted: Thu May 22, 2008 1:07 pm 
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spraycanmansam wrote:

Just in case your wondering why I'm so interested, I'm planning on using mini front suspension in the rear :wink:


Just watch out when you lift off the throttle...

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PostPosted: Thu May 22, 2008 3:19 pm 
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brickworx wrote:
spraycanmansam wrote:

Just in case your wondering why I'm so interested, I'm planning on using mini front suspension in the rear :wink:


Just watch out when you lift off the throttle...


Why's that?


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PostPosted: Thu May 22, 2008 4:32 pm 
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brickworx wrote:
spraycanmansam wrote:

Just in case your wondering why I'm so interested, I'm planning on using mini front suspension in the rear :wink:


Just watch out when you lift off the throttle...


paah! backing off if for wimps!!!


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PostPosted: Thu May 22, 2008 6:19 pm 
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I think you would classify the Mini front suspension as unequal length, parallel, upper and lower control arms.

The only difference between it and upper and lower A-arms is that the Mini uses the tie-rod to control longitudinal forces (longitudinal defelction under braking and acceleration) while A-arms do it integrally due to their design (width of the pivot end).

No problem with spherical bearings on the tie-rods and lower control arms.

I think Steve is referring weight transfer on lift off from the back to the front. If you have good weight distribution, low COG and low roll centres then this becomes less of a problem. Hopefully Sams Mini will have 50/50 weight distribution (or very close to it, due to the engine being mid-mounted where God intended) and the static COG's will be very low (most likely about 50mm off the ground - front, and about 100mm - rear) and the roll centres close to the centrelines.

Regards,
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PostPosted: Thu May 22, 2008 8:30 pm 
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Archangel007 wrote:
due to the engine being mid-mounted where God intended


exqueeze me? God (aka Alec Issigonis) always intended for the motor to be in the front

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PostPosted: Thu May 22, 2008 8:47 pm 
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The problem with lift off is that, as the rear suspension unloads, camber will move from negative towards zero or positive. Not as much as a VW or old Merc but similar.

"What's the deal with the tie rod bars? With an A-arm setup both ends are rose-jointed, where with the mini the lower arm is made up of a lower control arm ( I'll be using rose-jointed arms ) and a tie rod bar which doesn't exactly pivot as such because it's bushed"

The lower arm/tie rod form a wide based lower A arm. The tie rod does pivot in its bush which is why you don't use two plastic bushes on the front end.

Cheers, Ian


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PostPosted: Thu May 22, 2008 9:11 pm 
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Archangel007 wrote:
I think you would classify the Mini front suspension as unequal length, parallel, upper and lower control arms.

The only difference between it and upper and lower A-arms is that the Mini uses the tie-rod to control longitudinal forces (longitudinal defelction under braking and acceleration) while A-arms do it integrally due to their design (width of the pivot end).

No problem with spherical bearings on the tie-rods and lower control arms.

I think Steve is referring weight transfer on lift off from the back to the front. If you have good weight distribution, low COG and low roll centres then this becomes less of a problem. Hopefully Sams Mini will have 50/50 weight distribution (or very close to it, due to the engine being mid-mounted where God intended) and the static COG's will be very low (most likely about 50mm off the ground - front, and about 100mm - rear) and the roll centres close to the centrelines.

Regards,
Tricky


I love your brain... It's reassuring to know that the person working on my car has his head screwed on tight :wink: 8)

So rose-jointed Mini lower control arms and rose-jointed tie-bars would be very similar to a conventional a-arm? Just a very wide one...


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PostPosted: Thu May 22, 2008 10:07 pm 
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simon k wrote:
[exqueeze me? God (aka Alec Issigonis) always intended for the motor to be in the front


Perhaps I should have said "As God intended all sports car engines to be located"........

After all, it is all about perfect weight distribution :wink:

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