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TR2/3/3A TR3 rear suspension

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W

wifegonnakillme

Jedi Hopeful
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This is a tough question to pose since its as much about the feel of the car as anything specific...
My TR3 has been restored to driver status - meaning, all things needed for a safety (including alignment and new tires) plus the body have been done - but when i drive it the handling seems off somehow -
I know the cars have a bit of a tendancy to oversteer and I sense that on corners - but i'm wondering how i can tell if my shocks or springs in the back are shot? I joke with passengers that most of the rear suspension is in the tires as it seems to bottom out easliy on bumps...this bottoming out is what i sense on corners, feels like i can take to car to a point and if i go further it will seriouly oversteer
So the question is, have any other TR3 owners updated the rear suspension, and if so, was it worth it? I don't want to change the character of the car too much, but being a new owner, i'm not really sure what that character is...
Another forum member has offered up a comparison drive in the near future, but would love to hear from others that might have dealt with this,
Cheers,
Kerry /ubbthreads/images/graemlins/canpatriot.GIF
 
Kerry,
Good question and I wish I knew the answer.
How hard are you cornering when you experience this? My 3 rides 'firmly' but that is normal for the design.
I am aware of upgraded lever shocks for the 3 but it's recommended to weld stronger mounting plates on for the added stress encountered.
I'm waiting for someone to respond to your testing question as I'd like to know how to do that to.
Pat
 
the character of the car is that you can take the car to a point and if you go further it will seriously oversteer...

/ubbthreads/images/graemlins/smile.gif ... sorry- but they do have a history of going belly-up. Learn the limit and try very hard not to go past it.

The axle sits on top of the frame and only has so far to go.

I'd pull the shocks and make sure that they are full and give resistance when you pump em up and down.
 
Hi,

I own a TR4, not a TR3, which has a slightly wider track but otherwise the design of the rear suspension and handling characteristics are really quite similar.

The first things to check are air pressure in the tires, front and rear, along with the design of the tires themselves. Too low tire pressure will allow the tire to deform and roll over sideways on the wheel, which will reduce it's contact patch with the road and lead to more oversteer. Too high tire pressure causes the center of the tire's tread area to bulge outward, with a similar effect and result. Some tires simply aren't good handling and are more prone to break loose, causing oversteer if the rear of the car let's go first, and understeer if the fronts release before the rear. I think often that modern radials are a bit grippier than the original, bias ply tires these cars were designed to use. This can mean radials are will into oversteer (or understeer, depending upon the particular car's propensity) with less warning and controllability.

Are there any anti-sway bars installed on the car? If so, in particular a rear bar can cause oversteer. A rear bar is not generally recommended for the solid (live) axle TRs.

Next, is it possible the rear springs have lost some of their arc? The bottoming out you describe leads me to believe they might be sagged. Certainly, if the car bottoms on the suspension stops it can go into oversteer rather sharply at that point.

New leaf springs might be in order (or have the old ones re-arced). There are uprated "competition" leaf springs available that will help prevent bottoming, but will most certainly make the car ride harsher.

There are other things in this area to look at. Especially the bushings at the front eye and at the rear shackles, if any of them are old, worn out rubber-type that are letting the springs move around a lot.

Finally, inspect the frame around all the mounting points - front leaf spring mounting pin and rear shackles in particular - to see that there are no cracks and is no flexing going on.

Frankly, based upon your description, the shocks would be rather low on my list of things to looks at, but still need to be inspected for leaks and or any roughness in their travel. It might help to go to thicker shock oil, too. At least oversteer is more controllable than understeer!

/ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]
This bottoming out is what I sense on corners, feels like I can take to car to a point and if I go further it will seriouly oversteer
Cheers,
Kerry /ubbthreads/images/graemlins/canpatriot.GIF

[/ QUOTE ]
Are you sure that what you feel is "bottoming out"? - or maybe the inside wheel is topping out?

As Jim says; "The axle sits on top of the frame and only has so far to go." ie, there is limited rebound travel. As the body rolls too far & the inside rear wheel drops, the axle with it's inside wheel will contact the frame under it & will be lifted. It's quite easy for the axle to lift the inside rear wheel when the limit of body roll has been exceeded. very similar to having an excessively stiff rear anti roll bar.

The good part, if there is one, is that as soon as the inside rear wheel lifts & you lose traction on the outside wheel, the car will skate a bit sideways & the inside wheel will regain traction. If the situation is not too severe, the rear end will just hop sideways a few times & you will still have control.

Lowering the car along with stiffer rear springs would reduce body roll & give more rebound travel. Otherwise, just take the corners slower. Any rear anti roll bar will make the situation worse as will shocks with stiff rebound valving.

BTW, the big Healeys have a similar frame setup & similar problems.
D
 
alan is correct as usual,
check that your suspension is not bottoming.put a blob of grease on the top of your axle stop and drive car to duplicate the problem.stop car and check if the grease was transferred to the "axle hoop stop". if it was then you are bottoming the suspension (a-ha!).you can add a front sway bar or upgrade the rear springs. if you upgrade the rear springs you need the rear shocks to be upgraded as well (apple hydraulics).or you may want to just rebuild the rear springs,shocks,and bumper stops, first to make sure the original is restored first before adding a front sway bar or bigger front sway bar. soft suspension is good up to the point that you are bottoming. if that happens you are in need of an upgrade or the original is sacked.
rob
 
I find this post interesting and informative. I would like to add that the wheel base on a tr3 is kinda narrow, so be careful if you are racing a Honda; you might just come full circle. I have been driving a tr3 for over thirty years on regular bases and have discovered that the back end will come around much easier than one would expect. I can remember more than once all of a sudden going in reverse at about fifty while I was staring straight ahead.
Sp53



WTN you the man.

Sp53
 
[ QUOTE ]
...Frankly, based upon your description, the shocks would be rather low on my list of things to looks at, but still need to be inspected for leaks and or any roughness in their travel. It might help to go to thicker shock oil, too. At least oversteer is more controllable than understeer!

[/ QUOTE ]Omigod, I'm about to disagree with you, Alan! But if my faded memory of my TR3A days is any indication, one of the first things to check (beyond the most obvious things like tire condition and pressure and loose or broken bits) is the shock action. If they've gone dry, they do nothing. If topping them up brings back some measure of function, cool; otherwise, this is a reasonable and worthwhile item to replace if all else seems ok. (OK, I guess I'm not totally disagreeing with you after all!) /ubbthreads/images/graemlins/grin.gif
 
I'm in the process of a frame off and am currently doing the rear suspension on my TR3. What I noted between the spring tension between old and new leaf springs was night and day. Also, the front eye bush on the leafs and rear shackle bushings were so shot, they more or less just crumbled away as I took things apart. I'm getting the rear shocks rebuilt, so I can't comment on their internal condition. My thinking is is that if nothing has been replaced over the last 40 years on your car, it could very well be a combination of things which is causing your problem. Why not replace everything? Its only money...
 
[ QUOTE ]
Omigod, I'm about to disagree with you, Alan!

[/ QUOTE ]

Hey, you are more than welcome to disagree at any time. /ubbthreads/images/graemlins/cool.gif Especially when I state a point so poorly!

Hmmmm. I guess what I was trying to say was: Beyond checking the shocks for proper action and no serious leaks, good solid mounting, good links that don't have any play and possibly increasing the viscosity of the oil in them, there's not much more to do with them. Basically that's what you are saying, too, I think.

Another thing that's just slightly been just touched upon in this thread is the inherent dampening action of leaf springs.

Even if the old leaf springs still have adequate tension to support the car properly - ie., they haven't sagged - when they are flexed the leaves rub against each other constantly. In fact, this self-dampening effect is one reason that Triumph was able to get reasonably good handling out of these cars while using the rather primitive lever shocks. (The IRS cars with their rear coil springs are another story, and a conversion to tube shocks can help their handling manners a great deal, IMHO).

Depending upon how much they are used and in what conditions, old springs often get rusty and dry in between the leaves and that in turn can lead to rather quirky handling. The rubbing action between the leaves is a bit unpredictable and erratic.

So, it might be a really good idea to try lubricating the springs and see if that helps. I've tried spraying on some motor oil while the springs were still on the car. But doing this I have little confidence that any of the oil will ever actually find its way in where it's really needed. A better way is to remove the spring from the car and just soak it in a bath of old, used motor oil for a few days.

At first it might seem a problem to find something that will hold the long leaf spring and enough oil to cover it. They don't sell "leaf spring soaking pans" at the local auto parts store! Just get a 4 or 5 ft. section of rain gutter from your local hardware store and cap off both ends to make a long, narrow "pan" for soaking. After the oil has had a chance to penetrate between the leaves, drain and wipe off the excess and reinstall the leaf spring.

The difference this lubrication makes *might* be quite noticible, but how much really depends upon the actual condition of any particular set of leaf springs. It's hard to predict how much it might help, without just going ahead and trying it.

An alternative I've heard about - but not tried - is drilling some holes to serve as grease passageways and adding a grease zerk or two to the leaf spring. Pump a few strokes of grease in there every so often to lube the springs and wipe off any excess that oozes out. Sounds ideal, *but* I'd want to do a lot of careful research before trying this because I am fairly certain that even a small hole drilled in the wrong place could quickly lead to a broken spring! Apparently leaf springs for some applications come right from the factory fitted with grease zerks. Perhaps it would be useful to ask around at a heavy truck parts store or suspension repair shop for some ideas. Anyone done this?

Another and possibly more final solution a few of us here have discussed is converting to monoleaf spring suspension.

Monoleaf springs are just what they sound like... A spring made up of a single, very thick leaf rather than a stack of thinner ones. A monoleaf can be made of various materials: sometimes steel, sometimes reinforced fiberglass or carbon fiber, sometimes a combination.

The general idea, though, is to remove all the internal/interleaf dampening of the typical multi-leaf spring and have a much more smoothly progressive and predictable suspension. Just like with the IRS cars, I think monoleaqf suspension would make converting to modern, tubular shocks essential.

Unfortunately this would be a rather costly modification - between getting a custom-made monoleaf springs and doing a tube shock conversion. But I think if done right it could really transform the car's handling characteristics. Anyone want to experiment with monolead spring rates and such? I might... Right after I win the lottery. /ubbthreads/images/graemlins/wink.gif

/ubbthreads/images/graemlins/cheers.gif
 
Reading this string instantly brought back a memory. Before trying racing I autocrossed constantly. One Sunday (late '68 maybe) this stripped 3A shows up and it's more than quick and he never spins an inside wheel. I just figure initially he must have spent 2 weeks pay on a limited slip and I wasn't going to catch him. But then I started to realize just how much more lean there was to his chassis than mine going through figure eights,etc. Finally I go over to find out the story. He tells me to look at the rear axle. I'm sure my jaw hit the tarmac. They (he and his father) had cut out a slot into the frame say two inches down giving that much more travel to the axle tube. Neatly welded it back up and added a steel u tube not unlike some small single hoop roll bars. The hoop neatly bolted down to plates welded to the frame on either side of the slot. Can't remember if there were other strengthening members. For years I've thought about replicating it, but could never pull the trigger. I believe he'd said his dad was an engineer. Never saw him or the car again. He also said there was no LSD and it rode so much better on the street.
Tom Lains
TS58107
TS8651
 
so what do you think about tube shock conversions on a TR3 Alan? I've seen a guy's version that he did on a live axle TR4 but I was not that impressed with the execution. What he did was mount the bottom of the shock to the existing link and then bolted a plate to the bottom-most corner of the body that forms the passenger shelf. Since no kits are available I see what he was thinking and there is a similar point on the TR3 that could be used.

The TR6 kits have a bracket that mounts to the frame itself and then provides an upper point to mount the shock. I think the configuration of the 3 and 4 doesn't allow enough room for that kind of arrangement.

What bugs me is putting a major stress point on body sheet metal instead of a solid connection to the frame.

The other hickup he had is that there are 2 different springs on the live axle 4 and I believe that the earlier spring has less of an arch (and is the same one on the 3) so you'd have to get a steeper arched later live-axle 4 spring in order for the shock to fit.

Have you seen a better application that would work on a 3?
 
Hi Jim,

Personally, with standard "multi-leaf" springs I don't think a tube shock conversion would be worthwhile. The internal dampening effect of the leaf springs "helps" the lever shocks do an adequate job. Lever shocks can be upgraded by going to larger ones (DAS10 instread of DAS9 on TR3/4), by changing the oil to heavier viscosity and by changing the valving or installing adjustable valves (Cambridge Motorsports). Larger leve shocks require larger mounting brackets be welded onto the frames. I think a key concern is overheating the shocks during hard use, and there might be some way to increase the oil capacity of the shock, too.

However, if someone really wanted to install them (or were using a monoleaf spring where it makes more sense) I have seen TR4 tube shock conversions that weld directly to the frame. Because of the cars' similarities, I would think these would work with TR3, too, although there could be some interference with the body and some sheetmetal might need to be rearranged. But, hey, I'm just speculating here, really am not sure one way or the other since I've never tried it.

I agree, it would be a major mistake to mount shocks to the body only. Even if that new mounting point were very well-reinforced and strong, the suspension would put a constant beating on all the body-to-frame mounting points, probably eventually ripping them apart. Now if some shock brackets were *both* welded to the frame and attached to the body in some way... that would be a good thing if done right, I would think, perhaps providing some additional rigidity.

/ubbthreads/images/graemlins/cheers.gif
 
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