TR Register Forum

The TR Register Australia Inc. forum dedicated to Sidescreen TRs and Derivatives
It is currently Wed Jun 19, 2019 6:47 pm

All times are UTC + 10 hours [ DST ]




Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Sun Apr 14, 2019 7:33 pm 
Offline

Joined: Wed Dec 18, 2013 5:05 pm
Posts: 303
I am hogging this forum but here is another issue.
When Bob Cousins bought the car in 1966 he dismantled, cleaned and reassembled the rear springs with good lubricant between the leaves. They have the same number of leaves as the standard ones on my other car, 6 I recall.
I installed them with new bushes.
Bob had the rear shocks rebuilt professionally and they move quite normally. A bit stiff but nothing out of the ordinary.
Now I am driving the car the rear suspension is very stiff on both sides. It is quite bouncy on the bumps down my rear lane.
I removed a shock to check it wasn't too stiff. It moves through full throw with only moderate pressure.I also backed off the rear hanger bushes as I had clamped them up tight.
The car is still pretty light, no upholstery except the drivers seat, no weather gear, windscreen, spare wheel etc.
The car was used primarily as a race car before Bob got it.
Would it be possible the springs are set hard for racing? I would have thought that would be achieved with an extra leaf which it doesn't have.


Top
 Profile  
 
PostPosted: Tue Apr 16, 2019 12:09 pm 
Offline

Joined: Thu Dec 19, 2013 9:35 am
Posts: 76
You can quantify the springs by measuring the spring frequency.
Disconnect or remove the shock absorbers. With car on level ground and driver in position have someone bounce the rear continuously then count the bounces for 30 seconds at least and extrapolate to a minute.
I believe Standard TR rear Springs should be about 130 Cycles per Minute, (CPM)
A sedan of similar weight might have a frequency of say 100CPM
Racing springs packs I think are set to about 145CPM
Springs set to 120CPM give a very comfortable ride but have a tendency to bottom out easily on our touring roads, which makes for other stress issues.
I hope that I am not too far out but it might give you something to discuss with spring makers.
Rob


Top
 Profile  
 
PostPosted: Tue Apr 16, 2019 7:29 pm 
Offline

Joined: Wed Dec 18, 2013 5:05 pm
Posts: 303
fingoon rob wrote:
You can quantify the springs by measuring the spring frequency.
Disconnect or remove the shock absorbers. With car on level ground and driver in position have someone bounce the rear continuously then count the bounces for 30 seconds at least and extrapolate to a minute.
I believe Standard TR rear Springs should be about 130 Cycles per Minute, (CPM)
A sedan of similar weight might have a frequency of say 100CPM
Racing springs packs I think are set to about 145CPM
Springs set to 120CPM give a very comfortable ride but have a tendency to bottom out easily on our touring roads, which makes for other stress issues.
I hope that I am not too far out but it might give you something to discuss with spring makers.
Rob

Thanks Rob. These springs don't bounce.
I think I have determined that they are Triumph competition springs. I talked with Bob Cousins, the previous owner, and as the car was a pure racing car before he bought it and it had competition front springs it is probable the rear ones were as well. I then discussed it today with David Clark and Viv Paine and my description of the movement range and symptoms seems to confirm this as being the case.
When the Register gets new springs in I'll change them.
Until then I'll wear a kidney belt.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC + 10 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group