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Rear suspension recommendations

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Triumphgt6er Avatar
Triumphgt6er Jim Snell
Cave Creek, Arizona, USA   USA
1974 Triumph TR6 "Bubbles"
My recently acquired TR is in desperate need of a rear end refresh. Did a fair amount of searching and wasn't able to find much comparison of the various spring options so thought . About 25 years ago I also updated the rear springs on my prior TR6 using TRF competition springs and liked the results. I don't recall for sure, but thing they were also lowering springs. I'm sure TRF has also changed suppliers or something in the last 25 years.

My initial plan is to put rebuilt shocks from Peter at Worldwide and will have him do the heavy duty valving. For the springs, I'm doing heavy duty and thinking the 1" lowering springs. It looks like Goodpart springs fit the bill (looks like TRF sells Goodparts for their 1" HD spring), TSI has a heavy duty lowering spring (anyone know who supplies them?) and British Parts Northwest also has a set (same question - anyone know who supplies?(?

Interested on feedback from others how have done the HD valving from Peter along with 1" lowering springs and who you got them from. Appreciate the info!

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tirebiter Jeff Garber
Dighton, MA, USA   USA
I can't give you much help but I maybe able to explain how to compare the springs from various suppliers. It takes a bit of assumption on you part as well as some cooperation from the suppliers you want to deal with.

The springs have a certain number of turns/coils. Count how many. More is a softer spring. Less is a stiffer spring.

Also consider the wire gauge/thickness/Diameter that the spring is wound from. Thicker is stiffer. Thinner is softer.

The outside diameter of the coil is also a consideration. Larger would be softer, smaller would be stiffer.

Uncompressed height has more to do with ride height than it does with stiffness/softness.

Assumption : Most springs available will likely be made of the same material if not very closely matched. You can get different spring materials if you go with coil-overs.

Spring stiffness or softness is measured at halfway between free height and coil bind. The "spring rate" is how many pounds it takes to compress the spring at this measurement point. Higher spring rate is stiffer. Lower spring rate is softer.

If you are going to use lowered springs you need to use a higher spring rate than stock to help prevent the suspension from bottoming.

When a spring is made it starts out as a piece of straight wire of a certain thickness and a certain length. The wire is wound around a form to make it into coils. Imagine the straight piece of wire held securely at one end. Put a weight on the free end to see how far the wire will flex. That is similar to compressing the coils in order to check the spring rate.

A longer piece of wire will flex more. A thicker piece will flex less. Softer springs generally last longer than do stiffer springs before taking a "set", which would be lower than when it was manufactured.

Cooperation from suppliers : Can they tell you the dimensions # of coils, Outside Diameter of the coils, wire diameter ? Can they tell you the spring rate.

I believe most if not all aftermarket TR-6 springs will be made to the same Outside Diameter. They maybe more concerned with Inside Diameter if thicker than stock wire is used.

maddmapper Avatar
maddmapper Ken Prentice
Victoria, BC, Canada   CAN
Am looking into the same things for my TR250 rebuild. I'm still on the fence with the HD valving for the lever shocks but I am sticking with levers rather than the shock conversion.

Regarding springs, I have stock springs on my TR6 but know a couple of guys that went the HD route with the springs on their TR250 and wish they hadn't as it makes for a very stiff ride (they both went the shock conversion route though). I was leaning the HD route but I don't mind the way my TR6 rides and based my research, I am going to go with the lowered (non HD) springs for my rebuild.

So many combinations and personal preferences to base things on.

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dsixnero Avatar
dsixnero Dan Colanero
Westville, New Jersey, USA   USA
Jim,I have the HD lever shocks with comp. rear spings,the shocks are great. Dan

Triumphgt6er Avatar
Triumphgt6er Jim Snell
Cave Creek, Arizona, USA   USA
1974 Triumph TR6 "Bubbles"
In reply to # 1348710 by dsixnero Jim,I have the HD lever shocks with comp. rear spings,the shocks are great. Dan

Thanks Dan!

Think I have my spring choice down to either the Goodparts springs or a set from BPNW. I like the fact that BPNW has an option for either lowering HD springs or stock height HD springs:

Stock Height BPNW
Lowering BPNW

Would love to hear from a BPNW spring user!



Edited 1 time(s). Last edit at 2016-02-22 02:11 PM by Triumphgt6er.

dsixnero Avatar
dsixnero Dan Colanero
Westville, New Jersey, USA   USA
Hey Jim,ask bpnw to measure the standing length of the hd stock springs and I will measure the set from trf that I have and we can compare-stay in touch,Dan

Triumphgt6er Avatar
Triumphgt6er Jim Snell
Cave Creek, Arizona, USA   USA
1974 Triumph TR6 "Bubbles"
In reply to # 1350334 by dsixnero Hey Jim,ask bpnw to measure the standing length of the hd stock springs and I will measure the set from trf that I have and we can compare-stay in touch,Dan

Hi Dan - I went ahead and got the BPNW heavy duty stock height springs during their sale this week. Got them today. Fronts are 9.5 inches; rears are 11.5. Compared the rears and they are virtually the same height at 11.5 (maybe an 1/8 difference at most). As you can see there are more coils in the heavy duty spring.

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dsixnero Avatar
dsixnero Dan Colanero
Westville, New Jersey, USA   USA
Jim, it seems to me that if,stiffer springs are the same hgt.,won't the car sit higher? and then getting the camber right with those TA bracket configurations can drive a person to drink.You could have had my four HD springs for 80 bucks,good luck. Dan

Triumphgt6er Avatar
Triumphgt6er Jim Snell
Cave Creek, Arizona, USA   USA
1974 Triumph TR6 "Bubbles"
In reply to # 1352621 by dsixnero Jim, it seems to me that if,stiffer springs are the same hgt.,won't the car sit higher? and then getting the camber right with those TA bracket configurations can drive a person to drink.You could have had my four HD springs for 80 bucks,good luck. Dan

Sounds logical. Talked quite a bit with Leighton at BPNW and they've sent me some testing they received from prior customers. Say they will end up stock height and haven't had any complaints or returns. Here's another piece of contradictory information. Free spring length would appear to be 11.5, but my Haynes manual says stock length was 10.92. Curious if that's a mistake in the manual an what something like a Bentley manual says is stock. Leighton also said if I don't like them they will return/exhange so other than some possible shipping costs and some time, nothing to lose there.

I'm waiting on Worldwide to get my shocks back to me (misplaced my paperwork supposedly). As soon as I get those back I can re-assemble and will report back. Stay tuned.....

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bergxu Avatar
bergxu Aaron Greenberg
Cincinnati, Ohio, USA   USA
I happened to stumble upon this thread recently as I've been thinking of freshening the springs on my totally stock '74 TR6. I've overhauled the suspension but used stock rubber bushings and have original type (but new) oil charged shocks in front and still have the lever shocks in the rear. I buy most of my parts from BPNW and was curious as to how you feel the HD springs did on your car. I have no interest in stiffening the ride of my car and I believe their HD springs are appx 15% stiffer than stock from what I've been told. Thanks for any input!

Cheers,
Aaron

tkamd73 Avatar
tkamd73 Silver Member Tim Bradley
Menomonee Falls, WI, USA   USA
Hi Aaron, we also have a totally stock 74, My son and I, recently replaced the rear springs with Goodparts lowered 470lb ones. Very happy with the results, ended up adding the 1/2 inch spacers as I didn't like the increased negative camber, so keeping the stock height. They stiffen up the back end just a bit, which we like. Have BPNW poly bushings, and looking to get the uprated shocks from Worldwide Imports. Tim

Patrick67 Avatar
Patrick67 Pat L
farfaraway, Qu├ębec, Canada   CAN
Hi,

I have increased negative camber on my 73 Tr6 and I wanted to correct this by switching to the
heavy duty springs. Would that correct the negative camber ? the springs I have now are stock and there are
1/2 inch spacers.

thanks



Pat

Triumphgt6er Avatar
Triumphgt6er Jim Snell
Cave Creek, Arizona, USA   USA
1974 Triumph TR6 "Bubbles"
In reply to # 1402723 by bergxu I happened to stumble upon this thread recently as I've been thinking of freshening the springs on my totally stock '74 TR6. I've overhauled the suspension but used stock rubber bushings and have original type (but new) oil charged shocks in front and still have the lever shocks in the rear. I buy most of my parts from BPNW and was curious as to how you feel the HD springs did on your car. I have no interest in stiffening the ride of my car and I believe their HD springs are appx 15% stiffer than stock from what I've been told. Thanks for any input!

Cheers,
Aaron

Hi Aaron - I ended up returning the BPNW stock springs in exchange for the HD 1" lowering springs. Felt the stock springs sat too high and were mushier than I wanted. I ended up putting in some Richard Good spacers that he custom cut for me (same price.....gotta love that) which were .3 vs. the standard .5 spacers. Came up with that size by measuring what was needed to take the negative camber out, but still keep it lowered as much as possible. If you're interested in how I measured it let me know (suggestion from Richard). My thought is start with the lowering springs and you can always shim it back up. You can't lower it if you start with the stock springs.

Am very happy with how things came out and it handles great. Here's a link to a recent summary of what all I did on my suspension rebuild:
http://www.triumphexp.com/phorum/read.php?2,1400997,1401112#msg-1401112

bergxu Avatar
bergxu Aaron Greenberg
Cincinnati, Ohio, USA   USA
Thanks Tim and Jim!

One of our local guys here in Cinci is giving the BPNW standard height HD a springs a try on his car and so I'm going to see how he likes it and if it doesn't rattle his teeth out I'm going to go the same route as him.

I don't want to lower because I have 205 Michelins on my car so I'm afraid I'll be getting too close to rub zone.



Edited 2 time(s). Last edit at 2016-09-29 09:58 AM by bergxu.

TR250Guy Avatar
TR250Guy Tim Moore
Dayton, Ohio, USA   USA
1968 Triumph TR250 "TRminator"
Granted its a TR250 but I put the BPNW lowered HD springs on with 15X6 wheels and 205 tires. No rubbing issues at all.



1968 TR250 "TRminator"
Owned since 1980
Frame off rotisserie restoration completed in 11-2014 by myself and my brother


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2015 Cincinnati BCD.jpg

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