Torque Steering?

[Leeds Sprint]

Hello All

Since I bought it a year ago, my Dolomite 1850 has always had some pretty floaty rear suspension. I thought that new shocks, springs and trailing arm bushes would have cured all my rear end problems, but I'm still getting a fair bit of what I think must be tourque steering?

When I first press the accelerator, a small amount of steering correction is required to keep the car tracking straight. When I lift off an opposite correction of a the same ammount is required.

Overall it makes for a less confident drive. I would love to tighten things up a bit.

Is what I am describing sound like tourque steering?

What is happening with the suspension and drivetrain to make the car behave in this way?

What can be done to reduce the effects?

A weblink to the Wikipedia entry for Torque Steering is below:

http://en.wikipedia.org/wiki/Torque_steer

In the entry it says that rear wheel drive cars do not suffer from torque steering and that more powerful cars are more affected. Does this sound right? I can't imagine that my 1850 would be considered a particulary powerful car.

Thanks

Chris

[1300dolly]

are the front subframe bushes in good condition? this may cause a similar effect.

[tinweevil]

It can't be true torque steer that's a wrong wheel drive (fwd) malady.

Didn't we have this with one of the USofA members? iirc turned out to be one of the rear suspension arms fitted incorrectly, bushes & washers in the wrong order?

[Leeds Sprint]

Those are intresting suggestions?

1) Where are the subframe bushes located that might cause the problem? And what should I be looking for to indicate that they are in poor condition?

Image of front subframe from Rimmers below:



2) Incorrect order of washers and bushes sounds like an alarming proposition! I don't think I would know how to make sure that my garage didn't get things like that wrong. I wonder which bits of the Image below could be affected by this problem?



Thanks

Chris

[1300dolly]

subframe bushes
159209
159211
155793
155794
138626
All the bits that are not washers or bolts ,although these can also wear.
difficult to tell if they are worn have a look to see if cracked or seperating

its a bit of a job to do these as the enginge is bolted to the frame but it is worth it in my expience
it may be a good idea to get a local dolly owner to drive the car to give a comparision.
can't help with the rear arm sugestion ive not experianced that one.
jack the front up (on subframe)and try the steering on full lock ,is there any difference in the resistance at steering wheel or by turning road wheels by hand?
altough madmarts next comment mat also be helpfull.

[Mad Mart]

I'd say it was the rear tie bar bushes. 149849 and/or 152767.

[DavePoth]

Having had experience of a car with a loose front and a loose rear, dodgy tie bar mounts does feel a lot like torque steer. The front mounts will pull to one side regardless of whether power is on or not.

[Mad Mart]

BTW I thought you only had torque steer with FWD cars?

[DavePoth]

IIRC, torque steer occurs when the driveshafts are unequal lengths. Due to the weight of the longer one, there's more torque to that wheel, and so the car pitches off in the direction of the shorter driveshaft. It shouldn't be possible in a RWD car unless the drivetrain is transversely mounted, although I don't know if it actually happens.

-edit-

Of course I should read up about these things. It is the unequal length driveshaft that does it, but I think it has to do with the eccentricity of the rotation of the shafts under power as related to the steering linkage. So it cannot happen in RWD cars unless they have rear wheel steering.

[Hasbeen]

This problem was quite common with a number of cars in Oz, in the 60s.
One of the major manufacturers was using an inferior rear axle housing, & most of them were bent, in the horisontal plane. If you put the rear end
on a wheel alignment machine, you would find them with toe in or out of
up to 5/16". This would make them pull one way on acceleration, & the
other way on deceleration.

We had to set up the front of some cars, with negative camber on one side & positive camber on the other, & perhaps 2 degrees difference in castor, to stop them pulling into the oncoming traffic.

Another manufacturer had good diff housings, but was very slack with
their instillation. They were often installed up to 1.3" forward or back
from their intended place, on the springs. Although the wheels were
parallel, they were pointing out to one side of the car.

This gave exactly the same symptoms, but was easy to fix. You only had
to measure the wheel base on both sides, & adjust the position of the diff
on the springs to make both sides equal.

Independent rear ends were even worse, at that time. Many mechanics
had no idea of what to do with them. I once found one with the nearside wheel base 5 inches shorter than the offside.

Its not too hard to check all this, with a tape, & with the car between a couple of parallel string lines.

[2F45T4U]

Torque steer is where unequal length driveshafts wind up at different rates. the shorter one doesn't wind up as much as the longer one so the drive is put down to the ground quicker through that wheel.

[1300dolly]

YES WE KNOW WHAT TORQUE STEER IS , READ THE ORIGINAL POST.
chris wants to know what is causing symptoms similar to torque steer.

[Toledo Man]

Getting back on topic:

I think Mad Mart has hit it on the head. Snowdrop's rear end was a bit "twitchy" before I rebushed the rear suspension. Once that was done it was cured. Replace your tie bar bushes Chris. I recommend PolyBush (as sold by Jigsaw) or you could splash out and get Super Flex ones. I've heard not-so-good things about the poly bushes that the Triumph-specialists-in-Lincoln sell. There's a guy from Barnsley who's restoring a Sprint and he got said bushes and one of them was the wrong size!

[Leeds Sprint]

Thanks Guys

There has been some very helpful advice here.

I'm sure both the tiebar bushes in the back and the subframe bushes in the front could all do with replacing. The bushes I have replaced so far have been trashed. Ideally I would like to know which of the two are cusing the problems as described above, as I would tackle those first.

While driving to work today I tried my best to see if the problem was coming from the front or the back, but it really is hard to tell. Maybe one of you would like to take my Dolomite for a test drive some time and give me a second opinion.

Yes..... it would appear that torque steer is not the correct term to describe the phenomenon I am experiencing. So I am happy to stand corrected there. Can anyone suggest an appropriate term to describe the problem?

When I had my my rear shocks and springs replaced the other week I was a bit dissapointed to find that my garage had used bushes from the "parts suplier in Lincolnshite". Particularly as it was my garage that reccomended Polybush shocks to me in the first place. Anyway they have tightened things up a fair bit, so we will see how long those last.

Thanks again for all your help guys.

Chris

[DavePoth]

If it's the tiebar bushes, it'll feel a lot different under power as compared to coasting. The subframe bushes will cause it to be constant, although in my experience worse under braking.