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Bottom arms and drive shafts
b14wrc - 18/8/12 at 09:08 AM

Hi all,



Just wondering about my bottom arms with respect to my drive shafts, I'm still designing the rear suspension. I think it's roughly going to be like this, any pointers?

Rob

coyoteboy - 18/8/12 at 10:16 AM

I'm not sure what your question is to be honest. You're going to need some bottom arms, I can tell you that

MikeRJ - 18/8/12 at 10:55 AM

And I don't think that roll bar is going to be very effective

matt_gsxr - 18/8/12 at 11:19 AM

quote:
Originally posted by MikeRJ
And I don't think that roll bar is going to be very effective


Looks like you might keep it to the £250 budget though.

b14wrc - 18/8/12 at 11:46 AM

Lol.

Sorry was in a rush when I posted.

I was just looking for pointers on how my bottom arms should align with the drive shafts? I know on the front its critical for steering characteristics, but are there any special considerations for my set up in the photo?

Oh, I thought that roll bar was quite good.....

May change it for some of that steel lying next to the build table to the left.

You would be surprised at my budget so far, reckon I've spent £700 on donor car and steel (plus bits and pieces) and I've sold about £350 worth of bits, so total is about £350 so far.... Which I think isn't too bad for the kit I have.

Rob

Doctor Derek Doctors - 18/8/12 at 12:00 PM

The original lower arms from whatever donor car you used for the gearbox and shafts would be a good place to start. They will definately clear the driveshafts and be upto the job.

MikeRJ - 18/8/12 at 07:10 PM

Since those uprights look like they are from a FWD donor, you are going to have to make links to tie to the steering arm to the chassis to hold the wheels pointing forward. The length and point of attachment of these arms will be critical, getting this wrong will give you significant toe changes as the suspension moves, and likely some evil handling characteristics. Avoid toe-out as the suspension compresses, some additional toe-in may be beneficial.

les g - 18/8/12 at 09:19 PM

AMI THE ONLY ONE THINKING IT.?????

BUT I THINK YOU NEED..........Neville Jones help here.....!!!!!

SORRY I'LL GET ME COAT
LES G

b14wrc - 19/8/12 at 10:08 AM

Hi,

I was hoping I could cut those steering arms off and mount the bottom are similarly to that of the sierra hub. Turning my hub through 180 degrees and having the ball joint at the top rather than the bottom. The macperson strut would then be upside down if it were thre.

Does that make sense? Toe will be set by adjusting one of the bottom arms attached to the hub.

Rob

froggy - 19/8/12 at 10:25 AM

I ended up with my shafts running downhill from the box at 5 degrees so they are parallel under power . The kimini book has sone good info and pics

mark chandler - 19/8/12 at 02:16 PM

quote:
Originally posted by b14wrc
Hi,

I was hoping I could cut those steering arms off and mount the bottom are similarly to that of the sierra hub. Turning my hub through 180 degrees and having the ball joint at the top rather than the bottom. The macperson strut would then be upside down if it were thre.

Does that make sense? Toe will be set by adjusting one of the bottom arms attached to the hub.

Rob


No need to cut them off, they provided plenty of stabilty when on the original car, you just need to take tie rods to the chassis in the correct position to eradicate bump steer, then you have a nice adjustment point.

So butcher the original steering rack, cut some threads on the arms and wack on some female rose joints

Just drop the shock onto the lower wishbone in front of the drive shaft.

[Edited on 19/8/12 by mark chandler]

b14wrc - 19/8/12 at 07:36 PM

Hi Mark,

That might be a better option, I don't know why I ruled out using the steering arms as another pick up point on the suspension, might make it stronger. Hoping to have 300bhp, so might need the extra support.

Aligning the shafts for when under load is a good point.

Regarding Kurts book Kimini, where is the cheapest place to buy it in the uk? I really would like to read it. Got slot of inspiration from the Midlana.

Rob

johnH20 - 19/8/12 at 07:37 PM

Hi B14wrc, I think the Sylva Riot/J13 does what you propose with the uprights. Suggest you take a look at one of them. As to lower links you obviously need to design the total geometry also having regard to available driveshaft plunge.