Novice suspension setup questions

[SK400]

Greetings

Can someone remind me:

1/ rake angle: what is the recommended front and back chassis to road clearance? and where on the frame is the height measured at?

2/ camber angle: on the post 2006 superlight models, what is the camber angle change from one full screw turn of the tie rod end into the upper A arm? any front camber suggestion for 13" avon ZZR tires ?

3/ tool to adjust spring compression: any recommendation on what tool to use?

 

 

thanks a bunch everyone

[yellowss7]

Seb, I believe it's 15mm lower in front than the back for the rake. measured from the front motor mounts and the rear tube just infront of the rear wing mounting point. How low you go up front is dependent on how brave you are with your sump. :jester: I seem to recall, 75mm as a safe road height but for track you could go lower. Just remember you need some clearance to get the car on and off the trailer.

 

I have a couple of C spanners that came with the car for adjusting the spring perches, but If you are careful You might be able to loosen them with a big screw driver and hammer, just be sure to take the weight off the wheel to make it easier.

 

Tom

Edited May 19, 2015 by yellowss7

[simon450]

Anyone know whether the caterham R500 Duratec dry sump set up uses -12 or -10 fittings?

 

 

Sent from my iPhone using Tapatalk

[SK400]

Thanks a ton Tom.

 

I just installed my new 13" Apollo avon ZZR tires combo (looks great!). However the front tires (185/55/13") are probably 3/4 inch or 1" narrower than my stock 195 Avon CR500 15" and my carbon fiber clamshell fenders look too wide for this new tire /rim combo. Should I be looking for narrower carbon fiber clamshell fenders and perhaps wingstays. Does such thing exist?

 

Also, any thoughts on the recommended front camber angle for these Avon ZZR tires?

 

Simon,

i'll look this weekend and send you a PM if I can figure it out. I have the cosworth dry sump.

[yellowss7]

Seb, around 3.5 negative camber is the Blat chat recommendation for the ZZR's. If you are switching back and forth between them and the CR500's then you could compromise with -2.75 to -3.0 if you didn't want the full -3.5.

 

And just to clarify semantics, your front wings are the Cycle fender type not Clams :jester: Clams are the old school style that I run on the Yellow car. They make tire width changes a breeze, and look way cooler. :smilielol5:

[Kitcat]

3.5 negative camber seems mammoth, I think I run minus 2 but... ???

Seb, where did you buy your Avons? And why did you switch from the 195 CR 500's?

The cycle fenders are about $250 per side, so not a cheap switch. I am running the CSR front fenders and have trouble finding anything small enough to fit under them.

[Croc]

That neg camber sounds right. I did not change it on either of my cars when I switched to 13 inch wheels and ZZRs and the fronts are wearing a little lopsided on track but I will just swap the tires around and run them reverse when they wear too far. Some of the guys in the UK swear by running the Avons backwards in the Caterham race series as the tread holds up better. I much prefer the ZZRs over CR500 although they will never be as quick as slicks. Roger Krause was excellent to deal with - he knows Caterhams well.

[SK400]

I bought the ZZR tires from Roger Kraus as suggested by Mike. Roger was a table pounder for these tires.

I wanted to go down and try 13" on my car so opted for the R620 setup (Apollo wheels and 215/55/13 in the back and 185/55/13 in the front) honestly without more thought going into it. But the swap from my 15" CR500 is not a straight forward swap .. the front wheel are 1.15" smaller in diameter and it throws the suspension setting and rake angle way off. On a separate note, i tried to adjust the camber this weekend but to no avail... got stuck at trying to loosen up the upper ball-joint from the upright but ended damaging the rubber gaitor.... Any tool or advice on how to remove the ball joint from the upright? officially standing in my way of setting up the car the right way .. and I have one more weekend left before trying Monticello.

thanks !

[yellowss7]

Seb, the traditional method, is bang it with two hammers. Really.:willy_nilly:

[slomove]

Not sure what may be relevant to Caterhams, but before my change to wide track on the Birkin I preferred loosening the upper a-arm suspension bolts and turn that part to change camber. Much easier than getting that tapered rod end bolt out. I think it just fretted/corroded with the aluminum upright.

Now, with the widetrack suspension the rod ends are seated in left-hand/right-hand thread bushings and I can adjust camber to any fraction of a degree in a minute with two wrenches. Pretty cool.

Edited May 25, 2015 by slomove

[SK400]

Really?! There is no other more graceful way? A pusher and puller? A dentist tool? Calls for an invention.

Removing the top wishbone is not completely crazy if it helps save some banging.

Let me know if you hear of any other method to help.

Thanks guys.

[jlumba81]

if the boot is already ruined you can use a pickle fork attachment on an air hammer.

 

 

[yellowss7]

No experience with this. http://www.sears.com/otc-ball-joint-separator/p-00971255000P?sid=IDx01192011x000001&kpid=00971255000&pla=&kispla=00971255000P&mktRedirect=y

 

But a BFH is still cheaper and quicker. :rofl: Get R Done! Tom

[CASwede]

Spin the nut to the bottom of the bolt. Cut a 3 or 4 inch section of 1 inch pine dowel. Place the dowel against the nut, and whack upward with and engineers hammer. The nut and soft pine wood will protect the end of the bolt. When tightening, spin it up with a non-nylock nut until everything is together and tight, then replace with a new nylock. There are one hundred different methods of voodoo that people have to unfasten that connection.

[Kitcat]

CASwede: And most of the 100 are on YouTube, just a quick Google search away.

[SK400]

So I ordered all the tools suggested. I'll attempt (again) this weekend.

In the meantime, I started to drive with the new ZZRs around town. the car feels different already, perhaps because the front wheels are slightly narrower and my rake is way off. The Steering feels more twitchy and responsive. Kind of cool.. but not sure how this will do on the track..

With all of your recommendations, my goal is to aim at a) 120 mm front clearance (versus recommended 145 mm for the street and caterham academy rules. BTW, that's what I had with my CR500) b) 2.75 or 3 degrees of negative camber to be able to interchange the ZZRs with the CR500 15", and 15 mm of rake to max weight distribution on the front end. I'll do all of this with 150 - 160 lbs ballast in the driver seat (4 bags of 40 lbs wood pellets). Let's see what this setup shakes out on the track.

 

As an aside, I really got tired of cleaning the streets for the city, picking up all sorts of debris and rocks because of the sticky tires. So I went to a custom shop and had quasi the entire car protected with the transparent stone guard film. Can't barely see there is a film on the car... and I don't feel as bad when I see (and hear!) rocks flying. Strongly recommend it .

[yellowss7]

Seb, you didn't mention what you were doing with setting the Toe. I had a little toe out which helps with turn in but is a little prone to tramlining on the street. (following the grooves, ridges etc) The other key things to consider is are you having any bump steer? which can be sorted with a shim or so under the steering rack and then the Castor, which is determined by the number of washers in front of or behind the front bolts on the lower wishbones.

Edited May 29, 2015 by yellowss7

[SK400]

Eureka! the ball joint remover tool worked like a charm. If careful, you can even remove the ball joint without damaging the rubber gaitor. So started at factory setting with a negative camber of 1.25 ish and turned in 6 turns.. setting the negative camber to 2.75. Can't really go further, i'm at the max of the threads. (curious how folks get to negative 3.5). so now, i'm at 130 mm in front and 145 mm in the back

 

As for toe, i'm now right around 1 degree toe out (changing the camber changed the toe). Do you think it too much? feels like i need to reign the toe back in a bit to toe out of 0.5 or so. I've left everything else equal eg bump steer and castor.

thanks!

[yellowss7]

Great news Seb. Way to keep at it. 5 weeks to go! Start polishing!!! Simon's red and white one is a year newer and still pretty shiny!! Tom

[Kitcat]

Toe out = turns in quicker/twitchier. Great for auto-x where top speeds are lower and all you do it turn. I like a bit of toe-in for track days as it makes the car more stable at speed. And Caterham turn-in is still pretty phenomenal. I suspect its a personal preference tho.