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Spindle/Upright pics and measurements
http://www.locostusa.com/forums/viewtopic.php?f=5&t=1292
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Author:  carguy123 [ September 30, 2009, 9:27 am ]
Post subject:  Re: Spindle/Upright pics and measurements

Learned something new today.

I've seen some people talking about the Chevette spindle and others about the Fiero so I presumed they were different. This is the first time I'm aware of seeing the 2 come together.

So Vic's comment about the dropped spindle and big brake kit for the Fiero was a way to tell us how to find that in the market place because the they will be listed as Fiero rather than Chevette? In the parts world it's not common knowledge they are the same?

Author:  Dave [ November 18, 2009, 11:57 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Weighed an absolutely complete Fiero spindle with all new, stock brake components - 26 lbs

Image

Author:  wftb [ December 30, 2009, 1:13 am ]
Post subject:  Re: Spindle/Upright pics and measurements

i just joined this forum as i am working on a book based RX7 donor locost .i am also a fiero owner/modifier .i drive the only turbo 2.2 ecotec fiero gt as far as i know .my suspension is tubular with coilovers at all corners and i also have street dreams by ross drop spindles .my brakes are lebarron discs (11"0) with camaro front calipers and cadilac rear calipers .if you take the stock fiero front caliper assemblyand cut off the the stock pathetic solid disc , you can adapt a lot of aftermarket and OEM brakes because it becomes a tophat rotor system .grand am brakes are doable and a lot of fiero people have adapted corvette brakes .when i bought my frame kit , the seller said i could use fiero spindles .he included ball joints that fit the manufactured a arms .i had to carve out the the spindles to get the ball joints to work but now i can get decent brakes and use a lot of stuff i just had laying around .fiero wheel bolt pattern is 5 X 100 , not real common but not a bad wheel selection on places like tire rack .

Author:  Norm [ January 6, 2010, 2:40 am ]
Post subject:  Re: Spindle/Upright pics and measurements

Chetcpo asked so here's my contribution:

Upright is from a Caterham non-wide track with the trunnion front lower wishbone attach. Accuracy is between .01" and .1" I'd say. If you need a particular measurement more accurately let me know and I'll try to measure it. KPI is within +- 1 degree or so.

Image

Image

Author:  chetcpo [ January 6, 2010, 2:42 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Wow, that was fast! :) Thanks Norm!

Author:  ottocycle [ January 13, 2010, 7:46 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Hello all.
I am doing some homework on front uprights and along with geometry and dimensions, weight is important to me. I am working on a lightweight car and have yet to find a better front upright than the old British favorite the Spitfire/Herald as used by Lotus and many English race and sports car makers. Is there a better more modern substitute?
I am thinking perhaps the Legends or Dwarf car guys might have a unit. I want to use aluminum brackets and brakes where possible. I do not want to have 20+ pounds of hub, rotor and upright bouncing at each front corner.
BTW: How heavy is a Miata hub/upright and what is its KPI?

Thanks.

Author:  chetcpo [ January 14, 2010, 1:06 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

ottocycle wrote:
Hello all.
I am doing some homework on front uprights and along with geometry and dimensions, weight is important to me. I am working on a lightweight car and have yet to find a better front upright than the old British favorite the Spitfire/Herald as used by Lotus and many English race and sports car makers. Is there a better more modern substitute?
I am thinking perhaps the Legends or Dwarf car guys might have a unit. I want to use Aluminium brackets and brakes where possible. I do not want to have 20+ pounds of hub, rotor and upright bouncing at each front corner.
BTW: How heavy is a Miata hub/upright and what is its KPI?

Thanks.


Miata is pretty darn heavy...
Here's some race car uprights:
http://locostusa.com/forums/viewtopic.php?f=5&t=8199

Author:  ottocycle [ January 14, 2010, 1:27 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Thanks for the advice. I contacted the company regarding one of the uprights. The all alloy units have steering arms that look too light for a 1,250# car with modern tires. Steering arms take a beating (that is why they are often forged), and while I am not saying that they would break I am afraid they might flex which is a big NO NO.
By the way, I saw your report on the string computer and Miata hubs. Have you played with longer wishbone lengths and how did that work out?
Thanks.

Author:  chetcpo [ January 14, 2010, 1:29 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

ottocycle wrote:
Thanks for the advice. I contacted the company regarding one of the uprights. The all alloy units have steering arms that look too light for a 1,250# car with modern tires. Steering arms take a beating (that is why they are often forged), and while I am not saying that they would break I am afraid they might flex which is a big NO NO.
By the way, I saw your report on the string computer and Miata hubs. Have you played with longer wishbone lengths and how did that work out?
Thanks.

Good. That was a long time ago. I abandoned the string computer in favor of the wishbone program. I've since built, raced, and sold the car.

Author:  ottocycle [ January 14, 2010, 1:39 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Is that Mike McDermott's wishbone program? Is available online and what do you think of it? I am a MAC user and I believe there is not a lot out there for that format.
Where did you race and how did it handle?

Author:  carguy123 [ January 14, 2010, 2:20 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

ottocycle wrote:
Is that Mike McDermott's wishbone program? Is available online and what do you think of it? I am a MAC user and I believe there is not a lot out there for that format.
Where did you race and how did it handle?


I'm a Mac user and I just run Windoze on my Mac when I need it. That's the beauty of the Mac, you can run it all!!

fortunately there are only 2 programs that I need the windoze for.

Author:  chetcpo [ January 14, 2010, 4:38 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

ottocycle wrote:
Is that Mike McDermott's wishbone program? Is available online and what do you think of it? I am a MAC user and I believe there is not a lot out there for that format.
Where did you race and how did it handle?


I autocrossed in WV and it handled well but I don't want to junk up a sticky thread going on about it.:wink:

Wishbone is a DOS program. Regardless of your OS the best way to use it that I've found is doxbox. http://www.dosbox.com/ You can download a version for your Mac.

Author:  chetcpo [ May 12, 2010, 4:44 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

john hennessy wrote:
if you project a line thru the top and bottom a arms they will converge at the instant center,
the rack hight is somewhat irelavant as long as the track rod is also on a line running to the same point,
if the ball joint on the rack is on an imaginary line between the upper and lower a arm pivots.

alas if the track rod has to be longer due to the fixed position on the spindle the track will change during suspension movement


I'm still not following you, I think you are seriously overcomplicating the whole thing.

If you are using a front upright from a production vehicle, place your rack at the same height as the outer tie rod pivot with the suspension at its normal ride height, in your desired alignment. Anywhere else and you introduce more bump steer. It really is that simple. :)

The instant center you refer to is always moving relative to the chassis as the suspension cycles through its range. It doesn't sit static in the chassis as the suspension moves around. When discussing bump steer you should only be concerned where it is at normal ride height. That will minimize the toe changes as it goes into jounce and droop. Since most of us are using production spindles/uprights the steering arm location is already determined, thus we really should only be concerned about the height of the tie rod end pivot at the end of the steering arm is at ride height in proper alignment. (caster/camber/toe/etc.) That's where the rack should go. :wink:

Author:  nisseven [ May 16, 2010, 5:55 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

That should be the end of that.
That is the best and most correct answer that I have seen on the subject of bump steer. Pity it is in the wrong thread. :BDH:
Bruce

Author:  nisseven [ May 16, 2010, 11:57 pm ]
Post subject:  Re: Spindle/Upright pics and measurements

Since this thread is spindle/upright measurements these are my results for MX5 NA model.
I was very carefull in measuring them and made a disc in the lathe to bolt the hub to so that I had a nice flat surface to measure from. One of the problems is finding the centres of the ball joints so made pointers to bolt in the holes.
The following were the results. Top b/j 25mm from top face and 127.5mm (5-1/32")from face of hub. Bottom b/j 32mm from bottom face and 77.5mm (3-1/32") from face of hub. Tie rod end pivot point came out at 20mm from face of arm and 66mm (2-19/32") from face of hub. Measured as per chetcpo square from the hub face the top b/j is 123.5mm from the centre and the bottom b/j 85.5 (3-11/32"). Measured between centres 212mm top to bottom b/j. Steering arm was 121.5 from centre and 58deg from bottom b/j and axle centre. Axle centre is 8.5mm offset from centre line between top and bottom b/j's. Of course the top b/j will vary given your choise as it is not standard part.
Chetcpo's measurements included the brake rotor whereas mine don't. Hope these are of some help to someone.
Top control arm is 250mm and bottom 350mm
Bruce

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