smdl
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| posted on 6/4/06 at 06:46 AM |
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Geometry Using Raceleda Components
During recent email exchange with Bruce at Raceleda (very prompt and helpful, BTW), I had indicated interest in their uprights, but had expressed
concerns with regard to the large scrub radius associated with the standard Cortina geometry. Here was his response:
"The Cortina has a small KPI (4.8) and you are right that this contributes to a large scrub radius. The best option to reduce the radius is to
run a Granada (7.4) with an Escort hub. This is possible with our system as the stubs, hubs and uprights are interchangeable."
I am interested in going this direction as I am using a Merkur XR4Ti (Sierra) donor, and want to match the front with the rear (book-width de Dion) as
much as possible. We don't have a lot of euro Ford stuff here, and I would like to go as light as possible, so it makes sense (to me) to
consider this option.
My question is: How much of an impact is the Granada/Escort combination have on the standard book geometry? Is this going to require a major
adjustments to the pickup points, wishbones, etc.? Has anyone as already done or considered this?
Technical drawings for the various components are located at:
http://www.raceleda.co.uk/tech_drawings.aspx
Any thoughts would be appreciated. I'm learning a great deal, but am still trying to get a good handle on all the suspension stuff.
Thanks,
Shaun
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andyb64
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| posted on 6/4/06 at 02:34 PM |
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I have changed from Cortina uprights to the Raceleda Granada uprights but with Cortina hubs and I have had to play around with the geometry. I
don't have any specific changes as I'm not building a locost but the top arm would need to be shorter which messes up the original
settings.
Hope this helps
Andy...
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cymtriks
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| posted on 6/4/06 at 07:52 PM |
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calcs done
from the raceleda drawings-
The Escort hub gives a mounting face to wheel turning centre distance of 3.3 inches with a 205/50-15 tyre. With a wheel offset of 38mm this gives a
scrub radius of 1.8 inches.
The Granada hub gives a mounting face to wheel turning centre distance of 4.27 inches with a 205/50-15 tyre. With a wheel offset of 38mm this gives a
scrub radius of 2.8 inches.
runing an Escort hub on a Granada upright would change this by only 11mm as this the width difference specified on their site. That makes the Granada
Escort combination, at 2.4 inches, worse than just using the Escort version which is what the book is based on anyway.
Have you got Raceleda's answer right? The numbers don't seem to make sense.
Ford geometry is terrible as most modern stuff runs much lower scrub radii, the Elise being 10.5 mm.
Alternative uprights include-
Lada (rwd version)
Skoda (rwd if you can find any, haven't seen one for years!)
MGF/TF
MX5
Elise
S2000
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smdl
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| posted on 6/4/06 at 08:09 PM |
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Thanks, cymtriks
Yes, I am certain that I have quoted Raceleda's response correctly, as I simply cut and paste it from their email.
With regard to the other upright options that you mention, I haven't seen any Ladas or Skodas for eons, and we didn't get the MGF/TF or
Elise in Canada. We do have the MX5 (Miata) and the S2000, so I guess those are options, but I was hoping to keep the same PCD fore and aft.
I'm really surprised by the scrub numbers that you came up with on these.  Very disappointed, as I thought that this was going to be the
answer for me...
Regardless, thanks for the help, and any other thoughts are appreciated.
Shaun
[Edited on 6/4/06 by smdl]
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scotmac
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| posted on 7/4/06 at 07:30 PM |
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I think Bruce was simply comparing the cortina stuff to the granada stuff...ie, granada gives a better scrub than cortina uprights, w/ their 4.8deg
kpi.
Since Bruce said that all his stuff is interchangeable, yes, it does appear that the escort stuff (uprights *and* hubs) might be the best option.
Shaun, is there problem w/ switching from the granada stuff to the escort stuff?
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smdl
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| posted on 8/4/06 at 01:33 AM |
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scotmac,
No, nothing really wrong with using the Raceleda Escort items, I guess, but from the analysis that cymtriks has done, it doesn't look like they
are much of an improvement over the standard Cortina items.
For that much cost, I would hope to get near to ideal geometry. I'll have to keep thinking on this...
Thanks, All.
Shaun
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Lippoman
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| posted on 8/4/06 at 04:37 AM |
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Book = Cortina?
Isn't the book based on Cortina, not Escort, uprights?
The mounting distance with (Raceleda)Cortina is ~115 mm (4,5 inch) so worst of the lot...
Aren't Raceleda components alloy versions of the Ford parts without changes in geometry? That was the impression I was under...
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