Tie rod ends

Does any one know if there is a tie rod end with the correct taper for the steering arm, but with a M12 thread to connect to the tie rods.

Cheers Mal

Hmmmmmm

Tiger tamer said:

Does any one know if there is a tie rod end with the correct taper for the steering arm, but with a M12 thread to connect to the tie rods.

Cheers Mal

Click to expand...

I'm guessing that you already looked into re-threading the rods as the easier approach? BUT, many of the recent baby sedans have M12 threaded balls which may just happen to have the forgiving taper. Good hunting . . . . .rw

Randy

I do have to cut and rethread the tie rods. But they don't have the dia for the Alpine tie rods I have. I will probably have to get some extensions made up or find some that will do.

Cheers

If you go into your local BNT they should have a catalogue that shows tie rod ends giving the dia of the top and bottom of the taper and the length if I remember correctly, as well as the threads. Or you may be able to ream the taper on your steering arms to suit a readibly available tie rod end.

Thanks grelley.

I am also looking at the M12 inner tie rods and would prefer M14. The M12 looks very light when I compare them to the original Tiger inner tie rods.

I am going power steer using a RX7 f3ds rack. The RX4-RX9 had M14 inner rods and from what I can see in a online catalogue, if the thread that connects the inner tie rod to the rack shaft is the same they should work. So I will check that option out as well.

After going back out in the shed the Taper on the RX7 tie rod ends is the same. Little longer length in the taper but the same at the same distance when measuring on the taper. If that makes sense.

Seems to me I found some Mazda MPV van tie rods the were thicker and had M14 thread... been a while
One way to adapt to the 5/8" UNF tie rod ends is with a transition male/female piece... a made a few out of hex back when I was still experimenting...

Jim
B382000446

Another option, if those don't pan out, is to use a "bump steer kit" like the ones sold for modern Mustangs and other things. Basically a steel or aluminum sleeve with the right threads for the rack on one side, and the threads for a rod end on the other side. There are some that come with a stud for the spindle side, but we have found that drilling it out to 5/8 (for use with a 5/8 rod end) is stronger. Then the rod end is bolted directly to the spindle. This is on heavy Mustang race cars, I imagine that you could downsize to 1/2 with no problems.

Look at these:
http://www.maximummotorsports.com/Bumpsteer-kit-1979-93-Mustang-tapered-stud-style-P449.aspx
http://www.maximummotorsports.com/Bumpsteer-kit-1979-93-Mustang-bolt-through-style-P448.aspx

Thanks for the replies. I have managed to find some 14mm rack ends with the correct M16X1 thread for end that connects to the rack. I still may have to make up some extensions as Jim has. The hex part of the rack end that you use to make adjustments is smaller than 14mm and is partly in the area I need to thread the rack end.
The bump steer kit may well be another good way to go about it if we are allowed to use them on the road over here.

Here is a pic of the rack in the car and the next problem.

Jeff,
How long is the adapter sleeve ( the red part ) ? approx

Cheers Mal

A bit more angle on that rack than my Miata one... very close to the frame rail. Mine is centered so might be a tad narrower than what you're using although I think it's very close to the Tiger rack length . RHD also has it's own problems with the lower rad outlet!!

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I ended up using the bump steer studs only...used a female LH thread 5/8" heim and a nice 'store bought' 5/8" male LHthread/RHthread adjuster. You could do the same sort of thing with a 5/8" male heim and a tube ( or hex ) threaded for 5/8" on one end and your ( shortened and re-threaded )metric tie rod on the other... Speedway sells them in either 7° Pinto or 10° GM...http://www.speedwaymotors.com/Adjustable-Tie-Rod-Adapter-Stud-to-Heim,3333.html I can't remember but think the Pinto was O.K. for taper. Lots of options... and hours to get it done Another thing to throw in the mix if helps... Alpine tie rod ends are 9/16" thread and come in both RH and LH thread although you have to buy them in handed pairs...

Another thing to throw in the mix if helps... Alpine tie rod ends are 9/16" thread and come in both RH and LH thread although you have to buy them in handed pairs

Click to expand...

Jim, that's what I am using at the moment. Both RH thread though. The new inner rack ends I have bought have M14 X 1.5 threads which are very close to the 9/16" thread of the Alpine tie rod ends. I can wind them on 5 threads before they bind.

Pic of the Alpine end and the new inner, held where I need to be.
Darn hex just in the way

Tiger tamer said:

How long is the adapter sleeve ( the red part ) ?

Click to expand...

About 6" or so. I have a few different sleeves, I'll check them out. Plus, I'm coming to NZ next week!

This one is about 4" for the sleeve, 6" overall. The rod end is 5/8"; the other side is M14, and its threaded about 1.5" deep. It appears to be a larger ID past the threads, so it could take a longer inner tie rod, until it bumped into the shank of the rod end.

Hi Mal

That tube might be just the ticket. I wonder if the length would be right using shorter tie rods. I'll post a pic of the one I have with the length. I can't be positive but I thought they were from a Mazda MPV van and DO have the 14mm thread
Good luck with the project
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Jim
B382000446

New problem. The rx7 series 6 fd rack is wider than ideal. I cut down the old rack ends and set it up connected to the steering arms. I am just getting binding in the ball joints on full lock.
Rack length from inner face of inner rack ends,
Tiger 590mm
Midget 630mm approx.
Mialta 630mm approx., from what I found on internet.
Rx7 s6 fd 680mm.

Of course bent inner rack ends would solve this problem. That should get the local parts guys scratching their heads.
I know of one car that had them

The Tiger rack end ball joints are able to be dismantled and shimmed for wear.



As you can see the Tiger ball joint is female where it connects to the rack. As it all comes apart this part could be remade with a male thread which would allow it to connect to the Rx7 rack.

The only thing is the inner rack ends would need to be shortened. They are probably never going to be used again as the original tiger rack was well worn.



Any thoughts welcome. I could admit defeat and get a Mialta rack, but I like the idea of bent rack ends as they place the load on the rack more directly down the rack. Having the inner tie rod at an acute angle puts lateral load on the rack that slipper pad has to take. I would think that is the reason they were designed that way.

Mal, I think I'd be looking for a Miata rack... I have a Miata ( in the car ), Tiger and Midget rack here.The width of the actual rack bodies are :

Tiger 489mm
Miata 492mm
Midget 495 mm

Your RX7 piece will probably be 50-75 mm wider than these which is why it's so tight on the side rail .

The inner tie rod ends butt up to the housing at full lock on the Midget but the Tiger and Miata ones travel into the housing at least 1/2" at lock so at a guess, the Midget has less overall travel. I don't have the exact figures close but IIRC both Tiger and Miata travel is just over 5" (130mm) The math sounds right as that leaves an effective 460 mm body between the inners.
I think using the longer MGB arms ( which you already have, ) takes away the need for 'bent' tie rods but the extra length of your RX7 rack takes that back.. and more ... probably even worse than stock geometry as far as ackerman angle!


Jim
B382000446

66TigerMK1A said:

Mal, I think I'd be looking for a Miata rack... I have a Miata ( in the car ), Tiger and Midget rack here.The width of the actual rack bodies are :

Tiger 489mm
Miata 492mm
Midget 495 mm

Your RX7 piece will probably be 50-75 mm wider than these which is why it's so tight on the side rail .

The inner tie rod ends butt up to the housing at full lock on the Midget but the Tiger and Miata ones travel into the housing at least 1/2" at lock so at a guess, the Midget has less overall travel. I don't have the exact figures close but IIRC both Tiger and Miata travel is just over 5" (130mm) The math sounds right as that leaves an effective 460 mm body between the inners.
I think using the longer MGB arms ( which you already have, ) takes away the need for 'bent' tie rods but the extra length of your RX7 rack takes that back.. and more ... probably even worse than stock geometry as far as ackerman angle!


Jim
B382000446

Click to expand...

I will heed good advice and find one. I did think I had one on the way but the owner didn't want to have to pack it and freight it.

Cheers Mal



Here is something else I just found. The MG RV8 steering arms are a little longer than the MGB arms. Slightly larger mounting holes than the MGB but the same spacing.

Geometry ?

AHA!! Who can do the geometric math on the RV8 arms with a Tiger rack? Does the A-angle improve enough?

Tiger tamer said:

...but I like the idea of bent rack ends as they place the load on the rack more directly down the rack. Having the inner tie rod at an acute angle puts lateral load on the rack that slipper pad has to take. I would think that is the reason they were designed that way.

Click to expand...

Not true. When you have a link with ball joints at each end, it is only capable of transmitting force in line with the axis from joint to joint. The shape of the part connecting them makes no difference. Because of the inherent geometry of the suspension with the rack so far forward compared to the tie rod end, there will always be an excess longitudinal load on both the rack and spindle; since the link can only transmit force in one direction, to get the necessary lateral component (to steer) it must also have a longitudinal component that makes the total force in line with the link axis. (Let me know if that is too much engineer speak and I'll explain it another way). That force is taken up by the bushings at the end of the housing. The slipper pad (assuming by that you mean the spring loaded aluminum bushing) is there to keep the rack tight to the pinion, so it doesn't want to climb off it with force.

A few other comments on the subject. Using a rack that is that much longer has a number of potential downsides. The first is that the bump-steer curves will be drastically different than what you are replacing. Not to say that the existing Tiger geometry is perfect (I don't know, but based on the Ackerman problem, I doubt that much thought was put into it) but it could be quite bad with that kind of change. Also, the longer rack/shorter tier rod combination makes all the angles get worse with travel. You already ran into the problem with running out of travel on the ball joint. I'm guessing that if you are changing to a power rack you also want to make the ratio quicker (shorter arm) which would make things worse. Also, have you checked the rack ratio (mm travel per rev of the input)? That could throw things off as well-- for better or for worse.

If I have all the dimensions I can calculate the Ackerman numbers... but don't forget that the longer arm will give you a slower ratio too.

Tie rods

0neoffive said:

AHA!! Who can do the geometric math on the RV8 arms with a Tiger rack? Does the A-angle improve enough?

Click to expand...

If you want to do the math, Dr Mayfield's website has all the formulas he used to calculate Akkerman angles. Also his consensus is that a whole new crossmember is needed to achieve the correct angles. Reference to his web site at "Mayfield Company"