RCR suspension link lengths
- Thread starter Roger Allen
- Start date
Hi Roger,
If you check on my website (link below) I think you'll find most of what you'll need.. A simple matter of counting threads but I think I also have some measurements there.. I'm in sore need of updating the site but it has much of the basics on my build which is still in progress..
Terry Oxandale
Skinny Man
Randy,
What suggestions or tips can you provide on the orientation of the rear trailing arms? You've offered some very helpful tips on the lateral links in this regard, but over the past months I've tried to gain some insight into the "suggested" orientation of the trailing arms themselves. For example, are they parallel to the ground AND each other. Most references I've seen do not reflect this, but instead indicate an upward angle toward the front mounting point (anti-squat?). My concern is toe-out movement as the suspension moves upward if this is so.
What suggestions or tips can you provide on the orientation of the rear trailing arms? You've offered some very helpful tips on the lateral links in this regard, but over the past months I've tried to gain some insight into the "suggested" orientation of the trailing arms themselves. For example, are they parallel to the ground AND each other. Most references I've seen do not reflect this, but instead indicate an upward angle toward the front mounting point (anti-squat?). My concern is toe-out movement as the suspension moves upward if this is so.
Hi Terry,
To be honest with you - I have not tried to out-science the engineers that have built the car.
Rather I have just placed the lower control arms parallel with the ground (both front and rear) which is the way that all automotive suspensions are originally designed to be..
What you see on my website got me to the point where I had achieved that at ride height.
I positioned the rear upper control rod/arm (not the forward link) to where it won't interfere with any of the chassis during suspension bump movement and also to achieve the 6.5 degree inclination angle as specified by RCR. Note that this inclination angle is measured from the flat surface at the rear edge of the suspension upright..
This adjustment is done by changing the lengths of the two radius rods (forward control rods) to cant the upright to the proper angle.
Note that on my car it took a a number of spacers at the lower control arm's inner heim/rose joint to bring the rear toe angle closer to what it needed to be rather than turning one or the other of the outer joints further than my comfort level. I'll replace those spacers with one made specifically for the task on my lathe.
The front I adjusted to where I wanted it to be in terms of caster and camber as I wanted to be able to position the bodywork as such to center the wheels in the arches..
I hope this is of some help...
To be honest with you - I have not tried to out-science the engineers that have built the car.
Rather I have just placed the lower control arms parallel with the ground (both front and rear) which is the way that all automotive suspensions are originally designed to be..
What you see on my website got me to the point where I had achieved that at ride height.
I positioned the rear upper control rod/arm (not the forward link) to where it won't interfere with any of the chassis during suspension bump movement and also to achieve the 6.5 degree inclination angle as specified by RCR. Note that this inclination angle is measured from the flat surface at the rear edge of the suspension upright..
This adjustment is done by changing the lengths of the two radius rods (forward control rods) to cant the upright to the proper angle.
Note that on my car it took a a number of spacers at the lower control arm's inner heim/rose joint to bring the rear toe angle closer to what it needed to be rather than turning one or the other of the outer joints further than my comfort level. I'll replace those spacers with one made specifically for the task on my lathe.
The front I adjusted to where I wanted it to be in terms of caster and camber as I wanted to be able to position the bodywork as such to center the wheels in the arches..
I hope this is of some help...
flatchat(Chris)
Supporter
Roger -- does 28" and 29" sound right for the lengths of the trailing arms? ---otherwise the answers to your questions should be in the online RCR manual.:blank:
Hi Roger,
That's correct. I had to remove the locking nut on the outside of the upper balljoint as well on my particular car in order to get the negative camber I desired.
So as to not be too confusing with the pictures - I need to explain that I placed the one loose nut next to the other on the inside just as a place to keep it for the time being.
Hi Chris,
At the moment my rear radius arm lengths are around 31" and 32" joint centre to joint centre.
Although I can see the initial set up data in the RCR Manual and some references to the number of exposed threads here and there I really was hoping for a list of nominal link lengths and confirmed wheelbase and track data. This, I reckoned, would get me in the ball park with all wheels nearly square before fine tuning for the toe, bump steer, camber, castor and king pin inclination - and then probably going round again a few times no doubt.
With the RCR monocoque looking quite accurate, having the link lengths ought to get the settings close I reckon - or am I missing something?
best regards
Roger
At the moment my rear radius arm lengths are around 31" and 32" joint centre to joint centre.
Although I can see the initial set up data in the RCR Manual and some references to the number of exposed threads here and there I really was hoping for a list of nominal link lengths and confirmed wheelbase and track data. This, I reckoned, would get me in the ball park with all wheels nearly square before fine tuning for the toe, bump steer, camber, castor and king pin inclination - and then probably going round again a few times no doubt.
With the RCR monocoque looking quite accurate, having the link lengths ought to get the settings close I reckon - or am I missing something?
best regards
Roger
Hi,
Further on setting up my RCR suspension.
I've got P205/60R15 front tyes and P295/50R15 rear tyres on my Mk1 RCR40 (with standard rear end). Can anyone give me the distance between the tyre inner or outer faces front and rear on a set up car at the axle centre line?
Is 'track' measured beteen the centres of the contact patches???
What wheelbase are you working to?
Coming back to my earlier post - I consulted the Carroll Smith book on static set up. He says try to start with the link lengths but they are rarely available so do a rough set up and get equality side to side and work from there and that's where I am.
kind regards
Roger
Further on setting up my RCR suspension.
I've got P205/60R15 front tyes and P295/50R15 rear tyres on my Mk1 RCR40 (with standard rear end). Can anyone give me the distance between the tyre inner or outer faces front and rear on a set up car at the axle centre line?
Is 'track' measured beteen the centres of the contact patches???
What wheelbase are you working to?
Coming back to my earlier post - I consulted the Carroll Smith book on static set up. He says try to start with the link lengths but they are rarely available so do a rough set up and get equality side to side and work from there and that's where I am.
kind regards
Roger
Allen,
sent you dimensions to your rogerdallen - AT - btinternet.com address
sent you dimensions to your rogerdallen - AT - btinternet.com address
Last edited by a moderator:
Hi Fran,
Looks like the Blackberry is giving trouble because only the following dimensions came through:
Upper rear link
Upper rear rad. rod
Lower rear rad. rod
So, I'm still short of the following:
Lower rear link
Upper and lower front wishbones
Front track (specify the reference point on the hub preferably)
Rear track - (ditto)
Wheelbase
I'm just after the nominal design lengths to get me in the ballpark and equal side to side.
regards
Roger
Looks like the Blackberry is giving trouble because only the following dimensions came through:
Upper rear link
Upper rear rad. rod
Lower rear rad. rod
So, I'm still short of the following:
Lower rear link
Upper and lower front wishbones
Front track (specify the reference point on the hub preferably)
Rear track - (ditto)
Wheelbase
I'm just after the nominal design lengths to get me in the ballpark and equal side to side.
regards
Roger
resent...
