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So I've lowered the rack in the Triumph to clear the bottom of the engine. To sort out the bump steer this will inevitably cause, I also need to lower the tie rod end. Normally, the tie rod end mounts on the top of the steering arm. I've drilled out the tapered hole to take a 5/8th" bolt so I can use spacers to get it to the right height. 

Everything is just mocked up with clamps and spacers while I work out where it needs to be. I just had these rod ends lying around and will probably be using different ones, but they will be the same bore/thread size.

This is where stuff would be if it had the factory tie rod ends on it. As you can see the tie rod and or rod end are too long. The rod end is 5/8" unf and the tie rod is 1/2" unf. The thread on the tie rod cannot be extended as the diameter reduces after the thread.

My initial idea is to shorten both where I have the red lines. And use a threaded joining thing, in blue, to join them. I think I would have the rod end always threaded all the way in, with thread lock maybe and do the adjusting at the tie rod end like a 'normal' car.

 

Does this look okay? Is there a better way to do it?

IMAG0862Draw.thumb.jpg.a077885434d7ca8f77bfe633085ce21e.jpg

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On 10/10/2018 at 20:07, Adoom said:

So I've lowered the rack in the Triumph to clear the bottom of the engine. To sort out the bump steer this will inevitably cause, I also need to lower the tie rod end. Normally, the tie rod end mounts on the top of the steering arm. I've drilled out the tapered hole to take a 5/8th" bolt so I can use spacers to get it to the right height. 

Everything is just mocked up with clamps and spacers while I work out where it needs to be. I just had these rod ends lying around and will probably be using different ones, but they will be the same bore/thread size.

This is where stuff would be if it had the factory tie rod ends on it. As you can see the tie rod and or rod end are too long. The rod end is 5/8" unf and the tie rod is 1/2" unf. The thread on the tie rod cannot be extended as the diameter reduces after the thread.

My initial idea is to shorten both where I have the red lines. And use a threaded joining thing, in blue, to join them. I think I would have the rod end always threaded all the way in, with thread lock maybe and do the adjusting at the tie rod end like a 'normal' car.

 

Does this look okay? Is there a better way to do it?

IMAG0862Draw.thumb.jpg.a077885434d7ca8f77bfe633085ce21e.jpg

Looks ok. The rod end will need a jam nut to lock it into the blue sleeve thing, make sure the threads go in 1.5x thread diameter,  make sure the rod end doesn't bind at full suspension travel,  including compressing the bump stop a bit, the rod end will need a large flat washer as a failsafe , and the bolt that holds it on should have a shank that is a good fit in the arm 

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11 minutes ago, rusty360 said:

Would anyone have the specs for seat belt mount doubler plates? Or do I need to buy the hobby car manual for that one section? And what about sprog seat teathers? Any legal requirements around these at wof time?

https://lvvta.org.nz/documents/standards/LVVTA_STD_Seatbelts_& Seatbelt_Anchorages.pdf

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  • 2 weeks later...

So what's "acceptable" bump steer?

I made a contraption to measure it.IMAG0881.thumb.jpg.086225bd37a2c2edfb88d66f1ba59afd.jpgIMAG0882.thumb.jpg.8a78cd12c72f0239d372b028c6d8fd0f.jpg

Ignore the g-clamp, the bolt is too short.

Over 100mm of travel, full droop to full compression, I'm getting 0.67 degrees of toe change. As the suspension is raised, it toes out. 

If I run the ride height I'm thinking of running, the travel will be reduced to ~60mm and the toe change would be about 0.45 degrees.

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1 hour ago, Adoom said:

 

Over 100mm of travel, full droop to full compression, I'm getting 0.67 degrees of toe change. As the suspension is raised, it toes out. 

If I run the ride height I'm thinking of running, the travel will be reduced to ~60mm and the toe change would be about 0.45 degrees.

What's that in mm?

https://www.lvvta.org.nz/documents/infosheets/LVVTA_Info_04-2010_Bump-steer_Measurement_Background_Information.pdf

 

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My brain melted trying to comprehend that lot...

In theory, if you can keep the strut distance the same as factory, or close to it, there shouldn't be much change from factory in bump steer, correct?

So for example, a shorter strut installed, with RCA spacers attached to bottom should keep the strut length not too different. It's all about keeping the steering arm connection close to stock distance from top hat position. Yeah / nah?

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18 minutes ago, Nominal said:

I'm confused by your question.

I've measured the up/down suspension travel in mm.

And the angle the wheel is toeing in/out in degrees. Which I calculated using the distance between the two pins and how much gap there is between one of the pins and the board bolted to the wheel hub. (as the wheel turns/steers one of the pins lifts up). mm by themselves are a bit meaningless if you don't know the distance from the wheel center the measurements are taken from. eg: The largest meausrement I got was 5.5mm, but if I measured further away, I'd have a bigger number for the same wheel angle.

I had read that pdf you linked. I can't use the method they describe because I've only got suspension(and modified steering) on one side of the car. 

27 minutes ago, Bling said:

My brain melted trying to comprehend that lot...

In theory, if you can keep the strut distance the same as factory, or close to it, there shouldn't be much change from factory in bump steer, correct?

So for example, a shorter strut installed, with RCA spacers attached to bottom should keep the strut length not too different. It's all about keeping the steering arm connection close to stock distance from top hat position. Yeah / nah?

Nah aye. I've lowered the steering rack, because there is an engine in the way, now I'm trying to fix the bump steer that has caused. I'm not talking about bump steer from lowering the car "too much".

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39 minutes ago, Nominal said:
2 minutes ago, Adoom said:

I'm confused by your question.

I've measured the up/down suspension travel in mm.

And the angle the wheel is toeing in/out in degrees. Which I calculated using the distance between the two pins and how much gap there is between one of the pins and the board bolted to the wheel hub. (as the wheel turns/steers one of the pins lifts up). mm by themselves are a bit meaningless if you don't know the distance from the wheel center the measurements are taken from. eg: The largest meausrement I got was 5.5mm, but if I measured further away, I'd have a bigger number for the same wheel angle.

I had read that pdf you linked. I can't use the method they describe because I've only got suspension(and modified steering) on one side of the car. 

Nah aye. I've lowered the steering rack, because there is an engine in the way, now I'm trying to fix the bump steer that has caused. I'm not talking about bump steer from lowering the car "too much".

It was just that the LVVTA discussion was around toe change in mm, not so much in degrees

Works out to about 3.5mm assuming 24" overall wheel + tyre diameter for the 0.67 degree

or ~2.55 mm for the ride height change.

If this is just one side, then the amount would be double.

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11 minutes ago, Beaver said:

He's spaced down his front cross member so factory strut length probably become irrelevant....??

Not that either. Cross member is in the same place, but the rack is ~50mm lower than factory. So I've also had to lower the tie rod end the same amount, which in theory gets the bump steer back to normal.

 

5 minutes ago, Nominal said:

It was just that the LVVTA discussion was around toe change in mm, not so much in degrees

Works out to about 3.5mm assuming 24" overall wheel + tyre diameter for the 0.67 degree

or ~2.55 mm for the ride height change.

If this is just one side, then the amount would be double.

My imaginary wheel/tyre/distance between the pins is 470mm or 18.5".

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1 hour ago, Beaver said:

He's spaced down his front cross member so factory strut length probably become irrelevant....??

Sorry I should have made it clearer, I was jumping on the bump steer question band wagon. Not commenting about his setup, I lack the know how to make comment on that bit.

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