Jump to content
Forum software update now live Read more... ×
Sign in to follow this  
boxofbits

TR5 rear springs on a TR4a

Recommended Posts

Afternoon All

Ive just tried a pair of 350lb rear springs on my TR4a which I believe are roughly equivalent to TR5.

I’ve now got about 1/2-3/4 degree positive camber. Driving it you can feel the spring is overcoming the damper on rebound so you get a further pitch from the suspension. I can see why Triumph had a problem sorting this as the ride is much better and more controlled damping wise with the standard 310lb spring. The ride height is also too high.

Has anyone else modified the rear springs without compromising ride height and camber and were uprated dampers also fitted?

 

regards

Kevin

Share this post


Link to post
Share on other sites
2 hours ago, Malbaby said:

What rating springs did you have in the car previously.

If they were 310, why change?

I’ve gone back to 310 lb as the ride height looks right. The TR5 is obviously the same body but if they used the same chassis arrangement then I assume they run much higher and with positive camber. The rear spring rate of the TR5 is I believe around 350lb

Kevin

Share this post


Link to post
Share on other sites

I have Moss TT4212 rear springs 420lbs and Moss TT4001 390 lbs on front. 1/2 ins lower and bit stiffer. Fitted in 2005 along with tele  conversion and Koni shocks. Also polybush spacers under springs 5mm.

Works fine for me, comfortable and stable. Ideal for touring and fast road use. As the rears are shorter than originals they can be fitted without using spring compressors.

Also have front antiroll bar.

Chris

Edited by ChrisR-4A

Share this post


Link to post
Share on other sites
On 12/1/2018 at 9:33 PM, boxofbits said:

 The TR5 is obviously the same body but if they used the same chassis arrangement then I assume they run much higher and with positive camber.

Kevin

No they dont, the camber is set using the trailing arm brackets and the ride height is the length of the springs and also the camber.

Stuart.

Share this post


Link to post
Share on other sites
4 hours ago, stuart said:

No they dont, the camber is set using the trailing arm brackets and the ride height is the length of the springs and also the camber.

Stuart.

Thanks Stuart, so with the stiffer springs on the TR5, approx 350lb, you would assume it would have to sit higher due to the higher rate spring, unless they altered the chassis/ trailing arm etc to bring it down. My TR4a sat a good 2” Higher with 350lb springs. I’ve also got 3/4 degree + camber on the pass side and about 1/2 degree neg on the driver side. It seems camber is completely dictated by how precise the chassis/ trailing arm mounting is which I’d imagine you’d be lucky if it was spot on, especially as most chassis’ have been reconditioned at least once, unless it’s a brand new CTM unit?

Another question is if you’re doing a resto and it’s not right, do you normally fit adjustable trailing arm brackets to get it right? I’ve checked the brackets btw with 2 notches outer and 1 notch inner facing up

Regards

Kevin

Edited by boxofbits

Share this post


Link to post
Share on other sites

No the camber is set using the 36 different combinations of 1/2/3 notch brackets There is no real difference in the trailing arm sections of the chassis between a 4a/5/6 its all to do with setting the arms right, you can fit thicker spring insulators to correct ride height differences and Triumph also used steel shims to alter them as well. A 5 will sit the same height as a 4a and so will a 6 despite the extra weight in the rear of a 6 its all to do with setting them up right. I dont use adjustable brackets.

Stuart.

Share this post


Link to post
Share on other sites

I am with Stuart on this . 

If you go to the Buckeye triumph site there is a chart which is perfect for the job and easy to follow.

Roy

Share this post


Link to post
Share on other sites
1 hour ago, stuart said:

No the camber is set using the 36 different combinations of 1/2/3 notch brackets There is no real difference in the trailing arm sections of the chassis between a 4a/5/6 its all to do with setting the arms right, you can fit thicker spring insulators to correct ride height differences and Triumph also used steel shims to alter them as well. A 5 will sit the same height as a 4a and so will a 6 despite the extra weight in the rear of a 6 its all to do with setting them up right. I dont use adjustable brackets.

Stuart.

Many thanks Stuart for clarifying this, and Roy thanks for the info.

I'm not keen on adjustable brackets either, but it looks like if I swap the passenger side brackets round it'll go towards negative, so I'll try that and see how I get on. Interesting to know there is a 3 notch bracket with the lowest hole ( was this made available for the TR6 for some reason)? This bracket should then give provision for further adjustment if the swap round doesn't quite give enough.

Thanks again for advice

Regards

Kevin

Share this post


Link to post
Share on other sites
15 hours ago, boxofbits said:

Many thanks Stuart for clarifying this, and Roy thanks for the info.

I'm not keen on adjustable brackets either, but it looks like if I swap the passenger side brackets round it'll go towards negative, so I'll try that and see how I get on. Interesting to know there is a 3 notch bracket with the lowest hole ( was this made available for the TR6 for some reason)? This bracket should then give provision for further adjustment if the swap round doesn't quite give enough.

Thanks again for advice

Regards

Kevin

This will help you understand whats going on http://www.buckeyetriumphs.org/technical/Suspension/RSGeometry/RSGeometry.htm

Stuart.

Share this post


Link to post
Share on other sites
5 hours ago, stuart said:

This will help you understand whats going on http://www.buckeyetriumphs.org/technical/Suspension/RSGeometry/RSGeometry.htm

Stuart.

Interesting and we’ll written article. Thanks

Kevin 

Share this post


Link to post
Share on other sites

Stuart

When you have to reset the rear brackets what do you use as a starting point say with the std springs on a TR5, then I suppose measure and see what has to be changed. 

What's the ideal starting mounting bracket positions inner and outer please?

John

Share this post


Link to post
Share on other sites
17 hours ago, John L said:

Stuart

When you have to reset the rear brackets what do you use as a starting point say with the std springs on a TR5, then I suppose measure and see what has to be changed. 

What's the ideal starting mounting bracket positions inner and outer please?

John

Hi John

If this is of help to your question to Stuart I believe the brackets you should be starting with are 2 notch ( up) on the outer and 1 notch (up) for the inner. You might not necessarily get the factory camber reading when these are fitted due to chassis variation/ repairs etc but once measured use that as a guide to see what bracket configuration you might need for a ‘ relative’ camber change. I would say about 1/2 to 3/4 max negative would be a comfortable unladen figure to go for. If you need to correct ride height after you can fit spring spacers, but like my car ensure first that body to chassis spacing is right first and even on left-to-right otherwise you’ll just be building in more errors. There are 36 combinations though many of them are unusable under normal circumstances I would have thought. Use Stuart’s link above

Kevin

Share this post


Link to post
Share on other sites
20 hours ago, boxofbits said:

Hi John

If this is of help to your question to Stuart I believe the brackets you should be starting with are 2 notch ( up) on the outer and 1 notch (up) for the inner. You might not necessarily get the factory camber reading when these are fitted due to chassis variation/ repairs etc but once measured use that as a guide to see what bracket configuration you might need for a ‘ relative’ camber change. I would say about 1/2 to 3/4 max negative would be a comfortable unladen figure to go for. If you need to correct ride height after you can fit spring spacers, but like my car ensure first that body to chassis spacing is right first and even on left-to-right otherwise you’ll just be building in more errors. There are 36 combinations though many of them are unusable under normal circumstances I would have thought. Use Stuart’s link above

Kevin

What he said ^ but dont forget you are supposed to set the camber with the car loaded other wise it will be dragging its rear on speed bumps, and also between alterations you do need to take it out and rag it round the block to make sure it has settled properly again.

Stuart.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use.