Rover 2000TC Rear Spring Stiffness?

#1
Hello all,
can someone tell me what the spring rate is for the 2000TC rear springs? The reason I am asking is that I fitted a set of 3500S springs some years ago to my 2000TC at the same time I installed the Ford V8. But the car has been plagued with oversteer, a very 'twitchy', light feeling at highway speeds. Not sure how it will behave if I really push it into severe cornering because I'm afraid to do so;-) Searching through the Forum archives I found some very informative posts by Chris York regarding the balance between front and rear roll stiffness and the contribution to oversteer if the rear roll stiffness gets too high. So I'm beginning to conclude, based on the Forum info, that I've altered the front/rear roll stiffness in a bad way.

Now I know the spring rate for the 3500S rear springs, i.e k= 260 lb/in (mine were measured at 254 lb/in) but nowhere can I find the k value for the 2000 rear springs. I am wondering just how much stiffer, if any, the 3500S rear springs are. If they are stiffer, then my next move will be to fit a stiffer anti roll bar up front to see what improvement in handling I get.

All help would be greatly appreciated.

Cheers,
Tom
 
#2
I'm extremely sure they are stiffer, Tom, but like you, I've not found values for the 2000 springs. I think I might start by fitting a set of V8 front springs before moving on to the rollbar. You ought to be able to get a bigger one of those made up locally. After all, it's only a spring steel bar with a hexagon machined at each end. You could even give them your current one to get the length and hex size off. Won't stop you using the car, but you'll definitely know about front end roll!

Remember that along with my V8 front springs and stiffer anti roll bar I also used the 10% uprate V8 heavy duty rear springs.

Chris
 
#3
Hopefully somebody else will have the definitive answer, however, the following might assist.

I can’t find any original 2000 figures, but have found a few references to spring rates in magazine articles published when the V8 was introduced, where note was made of the differences from the 2000:

Autosport: States spring rates increased from 150lbs/in to 170lbs/in. However, I suspect this relates to front spring rates only.

Autocar: States rear increased from 150 to 250 lbs/in. Also states weight distribution is 50/50 front/rear for V8, whereas 2000 was 53/47 front/rear. With a full tank fuel, the V8 was 60lbs heavier than 2000.

Motor: States front spring rates increased from 150 to 170lbs/in and rear from 230lbs/in to 265lbs/in (although later in the article it states rear spring rates as 260lbs/in!). Rear damper diameter increased from 1” to 1 + 3/8”.

There appears to be a consensus about the front rates, and as the V8 was not that much heavier than the 2000, I suspect the Motor figures are more likely to be accurate for the rear springs. If the front rates were increased by 20lbs/in, a similar but slightly higher figure for the rear (especially considering the slight change in weight distribution to the rear), might fit better with The Motor’s stated figures.
 
#4
That all looks right to me. The only surprise is that there is so little difference at the back. Mind you, the extra 10% of the HD rears made a large difference to Lucky.

So I think that confirms my advice above - fit a set of V8 front springs as the first act, followed by the uprated bar after you've assessed that change. You certainly won't ruin the ride quality just by the spring change. BUT there is only one location on the car where I would substitute Polybushes for the OE rubber and that is the panhard rod to the diff. Except of course - you won't have that set-up on yours with the Jag diff! The front suspension in particular is completely ruined by polybushing.

Chris
 
#5
tonys said:
I can’t find any original 2000 figures, but have found a few references to spring rates in magazine articles published when the V8 was introduced, where note was made of the differences from the 2000:

Autosport: States spring rates increased from 150lbs/in to 170lbs/in. However, I suspect this relates to front spring rates only.

Autocar: States rear increased from 150 to 250 lbs/in. Also states weight distribution is 50/50 front/rear for V8, whereas 2000 was 53/47 front/rear. With a full tank fuel, the V8 was 60lbs heavier than 2000.

Motor: States front spring rates increased from 150 to 170lbs/in and rear from 230lbs/in to 265lbs/in (although later in the article it states rear spring rates as 260lbs/in!). Rear damper diameter increased from 1” to 1 + 3/8”.

There appears to be a consensus about the front rates, and as the V8 was not that much heavier than the 2000, I suspect the Motor figures are more likely to be accurate for the rear springs. If the front rates were increased by 20lbs/in, a similar but slightly higher figure for the rear (especially considering the slight change in weight distribution to the rear), might fit better with The Motor’s stated figures.
Tony,
thank you for taking the time to research this. As you say, there seems to be consensus on the front spring rate increase. For the rear springs the service manual says 260 lb/in for the 3500S and I verified this by testing my rear 3500S springs before fitting them. The test results showed 254 lb/in so right in the ball park. I would guess that Motor made a typo when they said the rear spring rate increased from 150 to 260 lb/in. Seems like they got confused and quoted the front spring rate.

At any rate, I will try to source a set of 3500S front springs although these parts are becoming very hard to source here in the US and shipping from the UK, or NZ, or Oz is getting expensive.
Cheers,
Tom
 
#6
chrisyork said:
So I think that confirms my advice above - fit a set of V8 front springs as the first act, followed by the uprated bar after you've assessed that change. You certainly won't ruin the ride quality just by the spring change. BUT there is only one location on the car where I would substitute Polybushes for the OE rubber and that is the panhard rod to the diff. Except of course - you won't have that set-up on yours with the Jag diff! The front suspension in particular is completely ruined by polybushing.

Chris
Chris,
thanks for the advice. I'm currently pursuing a two fold path, i.e. sourcing a set of V8 springs, not an easy task here in the US any longer, and at the same time looking in to finding chrome vanadium stock to have a stiffer anti roll bar machined. The only problem with changing out the springs is that it is a pig of a job. I should have replaced the springs last year while I had the front suspension apart to replace the rubber bushings. Oh well, hindsight is always 20/20;-)

Just a note on the Jag diff; I salvaged the Panhard rod fitting from the Rover diff mount and welded it to my redesigned mount, complete with original rubber bushing. At the moment I don't know how the new mount scheme is behaving under load but plan to fix a small video camera under there to see what is going on. Could be interesting;-)

Cheers,
Tom
 
#7
You could always have the replacement front springs wound. All the data you need to give to a spring manufacturer is in the V8 workshop manual! In the UK this is pretty easy to achieve, there must be places in the US who will do similar.

Chris
 
#8
chrisyork said:
You could always have the replacement front springs wound. All the data you need to give to a spring manufacturer is in the V8 workshop manual! In the UK this is pretty easy to achieve, there must be places in the US who will do similar.

Chris
Hi Chris,
I'm in discussions with a coil spring manufacturer here in the US but don't have a V8 shop manual so have had to glean front spring specs from various sources. The one spec I can't find is the diameter, either OD or ID. Would you or anyone on the Forum happen to have that at hand?

So far this is what I have:
Free Length 17.1 inches (434.8 mm)
Wire dia 0.587 in.
Number of coils 7.33
Rate (k) 170 lb/in
Ends closed and squared

Is the above correct or have I made some errors? Any help greatly appreciated.
Cheers,
Tom
 
#9
With the Jag rear end, is the load path from the rear suspension into the body the same as original suspension? Lateral loads originally were applied to the chassis through the panhard rod, if you are now applying those loads at a different height that may be the issue, not spring rates.

Yours
Vern
 
#10
Vern Klukas said:
With the Jag rear end, is the load path from the rear suspension into the body the same as original suspension? Lateral loads originally were applied to the chassis through the panhard rod, if you are now applying those loads at a different height that may be the issue, not spring rates.

Yours
Vern
Hi Vern,
thanks for the thought. The Jag mounting scheme dumps loads inth the chassis exactly the same as with the original Rover diff. I used the same Panhard rod, along with the mount that I salvaged off the old diff mounting bracket.

The oversteering problem has been with me for some time now, way before I fitted the Jag XJS diff so I'm fairly sure it is something I've done with the suspension. Right now I'm starting some testing with varying tire pressures. But first have to fix the fuel pump, an SU pump that wasn't assembled properly at the factory, resulting in a puddle of fuel all over the garage floor. Good job I don't smoke;-)

Tom
 

Demetris

Well-Known Member
#11
302Rover said:
But the car has been plagued with oversteer, a very 'twitchy', light feeling at highway speeds. Not sure how it will behave if I really push it into severe cornering because I'm afraid to do so;-)
Tom, maybe i got your description wrong, but the way you wrote it, is seems that you probably have a problem on front end suspension geometry, possibly something that was upset with the different weight distribution of your new drivetrain, or a rear suspension alignment issue.
I understand oversteering as something that happens when you corner, rather than a straight line feeling.
My experience with my TC with standard albeit almost new suspension components is that if you just drive into a corner with too much speed with closed throttle, it will understeer.
However, with power on, it is beautifully neutral, even on 2nd gear hairpins. I understand that the torque of my engine, especially with the V8 diff, is just enough to maintain the balance. In similar conditions, with much more torque available as it is the case with your car, there is no way to avoid oversteer if you use all that torque. I understand that with too stiff rear springs this will happen earlier, but i doubt that standard V8 rear springs fall into this category.
 
#12
Apologies for missing replying to your messages earlier.

The data that I have for the front road springs on the V8 is as follows:

Manual Steering

# of working coils 6 3/8
Free Length 413.5mm 16.281"
Rate 30.35 kg/cm 170 lb/in
Inside Dia 4.625" (this is the registration diameter)
Outside Dia 5.789" (not critical)

Power Steering

# of working coils 7 1/3
Free Length 434.8mm 17.12"
Rate 30.35 kg/cm 170 lb/in
Inside Dia 4.625" (this is the registration diameter)
Outside Dia not known

I've frankly no idea why power steering springs are differently specced. The final ride height is meant to be identical and the spring rate is the same, so it appears to be solely a difference in wire size. The springs don't suffer from wind up as the steering turns, so there's no explanation there. As an engineer, I'd be more comfortable with the earlier, manual steering spec. The spring diameters are taken from my old manual steering springs.

What is critical is that you use a high quality chrome vanadium spring steel. The first set I had made went banana shaped quite quickly, this because the spring seats don't always lie vertical to each other.

The information given is sufficient for a decent spring manufacturer in the UK to select an appropriate wire size. Clearly, if the original wire sizes aren't available it is possible to play tunes with the combination of wire size free length and no of working coils - and this is what your supplier will do for you. They no doubt will ask for information beyond this in an attempt to avoid dusting off their brain boxes.....

Chris
 
#13
Hi Demetris

2200's use suffix A V8 rear springs and the difference in ride is extremely noticeable, so I think you are wrong on the question of difference in stiffness. I uprated my rear springs by 10% and can only just feel the change, for a difference to be really noticeable, as in the difference in ride between 2000 and 2200, I suspect the change is going to be in the rage 30% to 50%. 2000's are acknowledged to be extremely softly sprung.

Chris
 
#14
One thing we failed to mention on straight running. I've found that the toe in, or tracking, setting is critical for straight line stability. You should aim as close to parallel, or zero, as possible, with any error towards toe in. That is front wheels closer together at the forward extremity than the rear.

There is an engineering explanation for this unusual result. The front suspension has very pronounced camber change in bump. When running straight this has the effect of changing the level of road contact, and hence grip, of any tyre that is deflected upwards by a bump. If there is pronounced toe in or toe out, then the grippiest tyre will then "win" and steer the car in the direction of the tracking. This can be felt as nervousness over small irregularities like white lines etc.

Chris
 

Demetris

Well-Known Member
#15
Chris, it is true that i have first hand experience only from my car, however the differences you mention seem excessive.

The data of the 4 cyl cars make for an interesting comparison.

2000 models before suffix B
# of working coils 7
Free Length 16.5"
Rate 170 lb/in

2000 models suffix B onwards
# of working coils 8
Free Length 17.5"
Rate 150 lb/in

2200 models
# of working coils 6 3/8
Free Length 16.3"
Rate 170 lb/in

I have no data available for the rear springs, but as you can see the V8 front springs were just 13% stiffer from some of the 4 cyl models.
When i got my car it had a set of almost 40 year old 150 lb/in springs and i replaced them with a new set of early 170 lb/in springs, because it just happened to find these. Honestly, i don't remember any change in ride quality.
 
#16
Sorry Demetris - I was referring to the rear, 2000 vs 2200 / V8. On Lucky, the change in handling from going up 10% on the rears is quite marked, the change in ride only just detectable. Hence my comment about the 2000's being a lot softer than the V8's for there to be such a marked change in the ride quality between 2000 and 2200 / V8. Again referring to rear ride. I've never seen a poundage rate for the back of a 2000.

Chris

Tom:

Is that all you need information wise?

Chris
 
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