[race_prep] Guernsey Hillclimb 205 Build

[Miles 331 1 Cars]

What camber you running at the back?

On slicks you want more than 1.5 up front too

 

Got lost on the post after 52 pages so if it's been talked about then sorry

[wardy18 33 1 Cars]

Don't worry It's fine, I'm not sure on the back, I have some Skip Brown plates between hub and trailing arm so I'll have to check what camber that makes on the rear

[alexcrosse 124]

On slicks you want more than 1.5 up front too

 

depends what tyre it is really

[tri_longer 25]

What camber you running at the back?

On slicks you want more than 1.5 up front too

 

Got lost on the post after 52 pages so if it's been talked about then sorry

 

Does that depend on whether they are radials or cross plys as I was advised not to run more than 1 degree neg on cross plys as it destroys them, but you can on radials. Only going on what I was advised in the paddock so would be interested to know if this is not the case.

[Cameron 16]

Set up

 

Front - 300lb springs, ARB as standard diameter (i think) with adjustable drop links, 8.7" Avon crossply slicks on 9" rims

 

Rear - 21mm ARB, 8" Avon crossply on 8" rims

 

..Cross-ply slicks are very sensitive to changes in camber, so I would be aiming to keep body roll to an absolute minimum!

 

 

You can't get away with running lots of static camber with cross-plies like you can on radials, so 1.5Deg may be about the limit.

[wardy18 33 1 Cars]

I run Crossply 8.7/21.5/15 on the front and 8/21.5/15 on the rear both with A15 Soft Hillclimb Compound

[wardy18 33 1 Cars]

You can't get away with running lots of static camber with cross-plies like you can on radials, so 1.5Deg may be about the limit.

 

I had heard this previously also from a very knowledgeable guy who only runs 0.5 -ve camber max.......

 

The ideal way to tell, ive been told, is with a temperature sensor to test the temps across the tyre surface straight after a run to see which section is working harder then adjust camber to compensate

[Cameron 16]

Yep! I even mentioned that a few pages ago.

 

Carcass temps are one of the easiest and most reliable ways to tell whether your pressures & static geometry are right. I'd seriously recommend at least borrowing one for a day if you don't fancy splashing out, but they're a good investment as you can also get probes for surface temps to do brakes, or anything else you fancy!

 

You want to test 3 points across the tyre as soon as you come in from a run - outer shoulder, middle and inner shoulder - and compare the temps across the tread. As a generalisation, if you're hotter on the outer shoulder then you need more negative camber, hotter on the inner then you need less, hotter in the middle means your pressure is too high and colder means too low; this can be a very good way of getting towards the sweet spot as quickly as possible!

[wardy18 33 1 Cars]

Definitely going to get my own as its a very good tool, which would you recomend, Infrared or Probe:

 

http://www.ebay.co.uk/itm/Digital-Infrared-IR-Thermometer-Laser-Temperature-tester-Wireless-Gun-Non-contac-/230807066613?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&var=&hash=item35bd2c57f5

 

http://www.ebay.co.uk/itm/Digital-Thermometer-2-Way-K-Type-Sensor-Temperature-Probe-/170891503784?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item27c9ed68a8

[Cameron 16]

Probe, always! You need to stick it through the compound into the carcass to get the temps, infra-red will just do surface temp.

 

Edit - just noticed on the probe link it doesn't have the necessary spike.. have a look at tyre pyrometers to see what I mean.

Edited August 28, 2012 by Cameron

[Miles 331 1 Cars]

Just assumed Radials, My dad's got crossply's on his car, But it's 1938

[Anthony 1,003]

Don't worry It's fine, I'm not sure on the back, I have some Skip Brown plates between hub and trailing arm so I'll have to check what camber that makes on the rear

They're meant to be 1.0 degree negative camber and 20 minutes toe-in, assuming that they're fitted to 205/309 arms, although you can't always get them set exactly spot-on as it depends on the tolerance of the original arms.

 

Worth getting the rear geometry checked to make sure that they're setup properly as they are adjustable, particularly if it was a while ago that they were done and if you've since had the beam apart and adjusted the ride height. I have the original installation/setup instructions that I can scan in if you want them.

[wardy18 33 1 Cars]

Yes please. thanks Anthony, i must admit when i rebuilt the new beam with these Skip Brown plates it was hard to work out which way they should go so i had to use the Vernier Caliper to measure the thickness as obviously the top is thinner than the bottom for -ve camber and the front is thinner than the back to create toe in but i remember i could hardly tell a difference when doing it but think i got it right.

 

Bit of an effort to double check now though!!

[Anthony 1,003]

Did you not get them setup properly originally then? Your rear geometry is probably all over the shop if you just slapped them togeter and didn't check and adjust until it was all within spec - the plates are only there to make the calipers run true(ish) to the disk, and all the adjustment is related to the orientation of the stub axle.

[wardy18 33 1 Cars]

Sorry i was under the impression that these plates were just a basic upgrade that fitted between trailing arm and hub and with having very slightly differences in thicknesses it would give the required Camber/Toe.

 

These came off my last rear beam that i had with the black/yellow 205 which i couldn't use again because the LH trailing arm snapped in 2 when i hit the granite wall and wrote it off so i took the plates off and measured them and fitted to the new beam that came with the new shell.

 

Didn't think there was anymore to it??

 

Apologies for my ignorance if i have this completely wrong, as said previously the whole suspension set up is fairly new to me, especially so 3 years when i was doing this.

Edited August 28, 2012 by wardy18

[welshpug 1,661]

If you hit the wall hard enough to snap a trailing arm I would be dubious as to whether the pins were still bent to skip brown's spec!

[wardy18 33 1 Cars]

If you hit the wall hard enough to snap a trailing arm I would be dubious as to whether the pins were still bent to skip brown's spec!

 

The pins seemed good still as the wheel hit face on to the wall

[Anthony 1,003]

 

That's what the kit consists of (well, there's two washers missing in that photo, but you get the idea)

 

The stub axles are effectively bent to a given spec, which is what changes the rear geometry. The stub axle can be rotated in the arm to change the geometry slightly, giving you adjustment to make both sides the same and within SBC's spec of 1 degree negative camber and 20 minutes toe in.

 

The plates are only there to adjust the angle of the caliper so that it runs true to the disk. The plates do not in any way change the geometry of the wheel.

 

If I've understood what you're saying, if you're only running the plates and not the stub axles, then effectively all you're doing is making the calipers run skewed relative to the disk, and atleast until the pads wear accordingly, badly compromising rear braking. I'm slightly surprised that it even fits though.

 

 

That's what the whole kit should look like fitted.

[wardy18 33 1 Cars]

BOLL**KS

 

I really cant remember if i used the Stub Axles or not now you say it, more than likely i didn't as being quite naive i though the plates did the work.

 

I have the toe set up apparatus at home so i will check what toe is currently running and also the camber.

 

Can you still get hold of these full set ups from new?

[Anthony 1,003]

Yes, but they're not cheap - £200 ish from memory.

 

Should be easy enough to tell if the stub axles are fitted or not - look at the back of the arm and see whether it has the cap head bolt sat proud as per my picture above, or whether it is a standard stub axle that will be flush with the arm.

[wardy18 33 1 Cars]

Mine looks exactly like your does, that could be a good thing for me then

 

Will check later on at the camber/caster.

 

So to adjust you need to undo the Cap head bolt and turn the stub axle, will the stub axle turn easily, what method is best for this?

[Anthony 1,003]

Instructions:

 

 

(click for larger version)

[wardy18 33 1 Cars]

Great Thanks Anthony, been a real help

[Miles 331 1 Cars]

I'd get some proper one's if your changing them, After trying to adjust a set of these Skip B ones it's a half hearted measurement of Camber etc

[wardy18 33 1 Cars]

Ill be having a look later on today hopefully, i cant see they would be a bad set up if you can get the right results from them, is going to be a bit of a faf trying to set them up as it will be a lot of re-adjustments and re-measuring and because the toe apparatus i have does the total toe of both wheels and not individual wheels so if its only reading a total of 20 minutes and for both wheels, according to above, i should have a total of 40 minutes i wont know which wheel is out, the only slight indication i will have is by checking the camber of each wheel as when i hit 20 minutes on each wheel the camber should be -ve 1 deg!!

Edited August 29, 2012 by wardy18