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Rack & pinion conversion


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I am planning to convert the steering on my TR3a to rack and pinion next spring. In speaking to a fellow TR owner, he has recommended the Protek one.

 

Has anyone used this make, if so how successful is it?  Also as a matter of interest, what happens to the centre horn and indicator unit?

 

I would value all of your comments and experience on this subject.

 

Chalky ???

 

----------------

1959 TR3a TS61652  almost on the road......yippeeee!

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You are aware that your indicators will have to move from the centre of the wheel to a stalk or switch?

 

Revington do a refurbished and uprated steering box, which, coupled with an uprated idler arm and uprated drag arm make the old type of steering work much better.

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If you don't mind originality and your steering box needs recon. I can only advise to go for a R&P. Steering is so much lighter and much more direct. I have one from Moss based on the rack of a Mini one and the fitting, a piece of cake, is same as the one from Protek. I am very pleased with it. I dont mind a new switch for the indicators. I have put it on the dash behind the stwheel and the stalk length is such that I can easily reach it with one finger and keep both my hands on the wheel.
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I got the Revington rack on my 3, combined with a full front suspension modification, 3deg trunnions and Tr6 upper wisbones and adjustable fulcrum pins   :)

Cornering is great, steers almost better than the 6.

The backside is that some welding is required.

Clive, what are indicators for, they just violate your privacy, no one is supposed to know where you are going to  :P

Jean

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Forgot to mention that, like Jean I ahev a modified suspension(uppper and lower trunnions, late upper wishbones, spax and springs). Although I am convinced that the Revington system might be the optimum choice I also believe it (the fitting)is an overkill for a roadgoing car. The fact that it needs to be weldedon, might limit installation when the body is off or at least the engine is out. Protek based fixing systems (bolt on) can be done with both body and engine in situ. Only the front appron needs to be removed. Also when you compare prices you will understand exactly what I mean with overkill.
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I do not have any figures in front of me, but I think the prices of the racks are more or less the same.

The brackets on my car were welded with all in place, except the front of cause.

The Revington price includes 80 pounds for the modified steering arms, but these are refunded when you trade in the

steering arms from your car.

Anyhow after I had removed the front, of a newly painted car, for the 3rd time to look after the steering house oil leaks I was so upset that the rack and pinion was for me the final solution :angry:

Jean

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with all respect for the outstanding quality of Revington items and the outstanding service, but my rack from Moss TT was nearly 1/2 price, no items to exchange, all included and ready to bolt on, no costs for welding. On top a promotional free delivery at the time.

It will always be so that there are companies who develop new solutions and ones that try to find (or copy)products based on standard mass production items. Both are needed to keep our cars on the road but also to keep products affordable.

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Chalky,

I fitted the Protek R&P kit about four years ago and am very pleased with it.

The installation was straight forward , but the body was off at the time.

Re-location of the horn and indicators was more complicated than fitting the R&P.....my set-up works OK but I am not yet completely satisfied with it.I am currently using a self-cancelling indicator switch from a Renault Estafette , but this could change shortly.

 

Cheers

 

Mike

http://mikek.9online.fr/index.htm

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Jean, the Moss kit is complete with tie rods and ball joints, all bits and pieces incl. (I did not have to buy one single washer or nut) to fit to the standard tie rod levers (106575 and 6).These are to be changed left to right but kept in the same position (not upside down). The fitting instructions were clear (even for me). Price in dec.2003 was 258 £. As said I can't compare with the Revington system, but this rack is 100% to my satisfaction, easy to fit (and thus to remove) and did not cost a hole in my pocket. the fact that it is based on a Mini one standard rack (BMW Quality)with modified tie rods convinced me further to go for this one.
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Jean, what do you mean by 'steering arm' : the tie rod levers that are bolted onto the vertical links? I've a Protek rack on my TR3, and now I'm changing to a 3° castor system : late TR4 or all TR6, I think it will be TR6.

The tie rod levers of a TR3 are 3cm shorter than the TR6 ones : this gives a 23% quicker steering of the wheels = a 23% quicker steering rack, but I don't know yet what the consequences are for the steering geometrie, especially the bump steering. The TR6 tie rod levers are protruding somewhat in front of the brake disks and the end of them is sitting much lower than the the TR3 lever.

With the protek rack, it is impossible to eliminate the severe bump steering in terminal droop (wheel falling) on my car, I don't know if this has much importance. Bump steering in bump (wheel rising) has very adverse consequences. I'm trying a TR7 rack with Triumph saloon tie rods now. The TR7 rack is 4.5 cm shorter than the the Protek rack, so the tie rods can be some 3 cm longer and this will better suit the geometrie of the suspension. The tie rod levers of a TR3 can be bent 1cm to the outside to fit the tie rods of 22 cm. The protek tie rods, incl. tie rod ends are only 19cm.

I will try to find out wich levers will eliminate the bump steering at best, trying different positions of the TR7 rack.

Jean , you say that the Revington system has modified steering arms/tie rod levers : do you know the length, from the stub axle centre to the tie rod end centre?

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Yes Marcel, that's what I mean in just more simple old fashioned way. Revington is modifying the tie rod levers, probably hot bending, to reach the optimal position that prevents bump steer and additional toe in of the outer wheel in turns. They also provide shorter distant pieces to bring them closer to the disk, like the TR4s. This will not allow the dustcover to be re-used unless you cut an opening in it, like the TR4's.

I have the impression that the rack in general is positioned lower on the chassis than the Protek rack. Under normal load the tie rods are in an horizontal position, with the tie rod ends, seen in a vertical plan, half way the brake disk. It's obvious, that whatever you do, you will have to search for compromises as you will probably never be able to compete with the steering performance of a modern car.

Just crawled under the 3 and measured the arms. On my car the distance between stub axle centre and tie rod end centre is 12cm.

Jean

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Thanks Jean, this is making things clearer to me. So Revington uses the original short TR3 tie rod levers and bend them as far to the brake disk as possible. I'll try this first, because with TR6 levers, the steering will be slower.
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I do not want to get in between you guys'technical discussion about bump steer (I do not understand much of this, so that one I leave up to you) but just like to inform you that by changing the original tie rod levers left to right as in the Moss system they come closer to the disk as well (if I am correct and forgive me if I am wrong). I have obsoleted the dust covers. Jean is correct, also this system sits higher on the frame than the one from Revington in the sense that the steering arms are not horizontal (it uses a protek frame)
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Rudi, I'm not that technical either, but if you look at the steering and suspension it's rather simple.

The front wheels due to the construction of the suspension, top and bottom wishbones move up and down in a vertical plan. On the other hand the steering tie-rod ends describe an ark, to follow the ark the wheels at the front side, where the tie-rods are mounted will be pulled inwards, toe in effect.

This toe-in will occur at the top and bottom of the suspension travel.

So when travelling on a bumpy road the steering geometry will constantly vary and this is even worse in bends where the wheels follow different circles on the surface.

Maybe someone get explain it in a better way :;):

Jean

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Jean , you can get toe out too, at the top and/or bottom of the suspension travel : i.e. when the tie rod is longer than one of the suspension arms, or if the tie rod is horizontal while the suspension arms are at an angle with the horizontal plane. I'm trying to iron out bump steering at the moment : the movements of the front wheels when rising and lowering the suspension arm can be very strange when the steering rack is moved in various directions.

I've mounted the complete wheel suspension of a TR6 on my TR3 together with a TR7 steering rack (57.5 cm wide, compared with the Protek/Moss rack wich is 61.8 cm) : with the steering wheel in the straight ahead position, the shorter TR3 arms(bent to the outside as far as possible) and the longer TR6 arms give about the same results : it is possible to avoid almost completely the bump steering from full bump(wheel rised) to 75% of the droop (wheel lowered), but whith the steering wheel is turned to the right or left, the results are better with the longer TR6 arms. I'm still looking for the best position of the steering rack, and I will made this position adjustable for later tuning.

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  • 2 years later...

Hello there,

 

I was wondering if any of you knows toe-in value for the TR3A... My friend is currently in the middle of modifying suspension and some other parts, but we couldn`t find those values in any of workshop manuals that we have.

Thanks for your help,

Pawel

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According to the original Workshop Manual, TR2/3 should have the front wheels parallel to 1/8" (0.125") toe-in. Nowadays, tyre places do it all on degrees, so you need to calculate that 1/8" across the radius of the tyred wheel (about 13.5"). According to my "Four Figure Tables", which I have had since the 1950s, the wheels should be set between zeo and half a degree toe-in.

 

I am a little concerned that people are contemplating the bending of steering arms in the home workshop - get it wrong and you, your pride and joy and a few other people might be finished. In the total scheme of things, steering is a vital safety feature, and it must surely be worth a few hundred quid to ensure it is safe? I'm not in the job of plugging any one supplier's R&P against another, but would just observe that I believe the Revington product is more expensive because it addresses the problem of bump steer and also provides Ackerman geometry - something not found in any TR2-6 when it was produced. Who/what is Ackerman? Ackerman geometry means that the wheel on the inside of the curve turns through a greater angle than the outer wheel, which is what it ought to do. That said, both Protek and Moss have sold many R&P conversion kits and the comments I have heard have been "why didn't Triumph do it" and "wish I had done it sooner".

 

Ian Cornish

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I have just looked up the toe-in figure given me by Neil Revington - he specifies 20 minutes of arc, which is one-third of a degree (60 minutes in a degree). This agrees with my figure of zero to half a degree.

Ian Cornish

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  • 7 years later...

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