TC Front End Improvements-Handling

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BCBryan
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TC Front End Improvements-Handling

Post by BCBryan » Sat Mar 30, 2024 3:53 pm

I have been researching this lately and note that here was a flurry of interest in this with Post here about a decade ago. I'm interested to learn what the current recommendations are and how people feel about the modifications they have done.
First let me define my uses for TC 6984. My wife and I intend to use this car for local drives, errands, and some touring which would involve highway speeds- it will not see any racing.

Using Mike Sherrells books and Steve Simmon's article on the use of heim joints; here's the mods that I can see being worthy of investigation:
  • 3/4" or 20 mm lowering blocks
anti roll bar
Panhard rod
Tie rod link (Simmons) and drag link joints
Steering box-top replacement, or entirely different box, VW or Nissan?

The weakness in the tie rods and the alternate joints should be a useful discussion. Hopefully there is some consensus after a decade of testing.
At this point I'm inclined to add the lowering blocks and the anti roll bar- but I'm open to people's viewpoints. Not locked into anything at this point.
I have left brakes out intensionally for the moment.
Thanks , Bryan.

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Steve Simmons
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Re: TC Front End Improvements-Handling

Post by Steve Simmons » Sat Mar 30, 2024 4:22 pm

Consensus? Good luck! :lol:

My thoughts...

I don't feel that an anti-roll bar is needed or worth the effort. TCs tend to corner very flat already and solid axles have a fixed camber. Roll bars seem to be much more useful on IFS cars where they can help control the two sides individually.

The rose/heim jointed track rod makes a slight improvement because it eliminates the play in the original ends, and the oversized bar won't bend like the originals do. It also won't allow your toe to change at speed, which I feel may be the biggest advantage. But it isn't a night and day difference and it certainly doesn't look stock so it's more of a personal choice than a necessary upgrade. The original does work fine. I changed mine mainly because I don't have stock steering so I saw no reason to have the original spring-loaded rod ends.

I've never tried the lowering blocks that Mike mentions on my own car. I did recently drive a TC that had them, and it drove and handled very nicely. I didn't drive that car without them however, so I can't really say how much of a difference, if any, they made.

I've put a few panhard rods on and they do seem to make a small difference in steering response. If your front end is set up badly, they make a much bigger difference by masking other issues. I don't see any reason to NOT put one on other than originality. Panhard rods have been a popular performance enhancement for a very long time for good reason. If someone sold one for the rear of the TC, I would like to try it out.

The steering box issue is a hot topic. What I can say is that any of the available boxes, including original, can be set up to perform very nicely. There are only two reasons I can see to change to a Datsun or VW... ease of steering and safety. Not to say the original is unsafe, but since these cars were new people have rightly complained that they were one of the car's weak points simply because they are under-built. The Datsun and VW are absolutely indestructible in comparison, and I've never head of one failing, or even wearing out. In new condition the BC box is fantastic. But the lower ratio of the aftermarket ones does make the steering much lighter, and on the highway or rough roads the car is noticeably easier to control. But the downside is that it steers like a truck in comparison to original. If you've ever driven a Model A, that's pretty much what the TC will steer like with the VW kit. Note that the newest VW kit offered by Moss has improved the steering ratio to be almost as good as the Datsun. I have one car with Datsun and one with BC and they both handle beautifully.
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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Sat Mar 30, 2024 5:49 pm

The front hubs on a TC are maintenance/wear items, like tires or kingpin bushings. They wear out-- and cannot be fixed or repaired, no matter what anyone might tell you. For some reason people think the hubs are not very important, but if they are not in excellent shape you will never ever get the car to drive right. They wear out where the bearings fit in. I got a new pair from AS around 8 years ago, and they were nice quality. I imagine FTFU would have good quality, also. I used the opportunity of new hubs to convert to tapered bearings.

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ROGER FURNEAUX
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Re: TC Front End Improvements-Handling

Post by ROGER FURNEAUX » Sun Mar 31, 2024 4:54 am

As usual, Steve is spot-on with everything he says! Fitting a Panhard rod certainly makes a difference: I supply them and many of my customers have remarked on the improvement. To my knowledge, nobody has taken one off, but I have heard of people removing their VW conversion and reverting to a properly set up Bishop Cam.

Roger
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Ray White
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Re: TC Front End Improvements-Handling

Post by Ray White » Tue Apr 02, 2024 9:44 am

I fitted a VW steering box because I have painful hands and dislike heavy steering while manoeuvring. The advantages of safety and stability were of secondary importance although I have fitted a Panhard rod because apart from the shock absorber arms there is nothing to locate the axle and stop it moving laterally.

I think the cars are low enough as it is... and the only real improvement in handling would be from radial ply tyres.

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Charlie Mac Quarrie
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Re: TC Front End Improvements-Handling

Post by Charlie Mac Quarrie » Tue Apr 02, 2024 12:44 pm

Purchasing new top front spring leafs from the UK that have had the front spring eye wrapped larger with a bushing installed to get rid of the excessive clearance is a nice noticeable improvement.
Charlie

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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Tue Apr 02, 2024 12:56 pm

Ray-
Thank you for being specific about why you went with the VW steering. Makes complete sense. I agree the Radial tire is a glamorous idea. My concern is fitment on the rear axle. Width is very limited on the TC, and the (bias ply) Model A tires I am currently running just barely fit. Getting the wheels on and off is like fitting a jigsaw puzzle, mentally. But it can be done.

The A tires I am running deliver exactly 4 inches of tread width touching the road. I always considered the extra width of the A tires to be a slight handling advantage, and the extra height of the tires is mostly offset by somewhat saggy springs that probably lower the car an inch or so.

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Ray White
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Re: TC Front End Improvements-Handling

Post by Ray White » Tue Apr 02, 2024 1:24 pm

Duncan M wrote:
Tue Apr 02, 2024 12:56 pm
Ray-
Thank you for being specific about why you went with the VW steering. Makes complete sense. I agree the Radial tire is a glamorous idea. My concern is fitment on the rear axle. Width is very limited on the TC, and the (bias ply) Model A tires I am currently running just barely fit. Getting the wheels on and off is like fitting a jigsaw puzzle, mentally. But it can be done.

The A tires I am running deliver exactly 4 inches of tread width touching the road. I always considered the extra width of the A tires to be a slight handling advantage, and the extra height of the tires is mostly offset by somewhat saggy springs that probably lower the car an inch or so.
I understand that Michael Sherrell runs radials with no issues. In fact, it may be that the overall diameter is slightly smaller which would presumably negate any problems with wheel changing. If that is the case - and I happily stand to be corrected on this - the ride height would be reduced. :thumbs:

I have also read that radials give a more comfortable ride....?

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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Tue Apr 02, 2024 2:23 pm

Charlie-
Curious how those Bridgestone radials working out?

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Charlie Mac Quarrie
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Re: TC Front End Improvements-Handling

Post by Charlie Mac Quarrie » Tue Apr 02, 2024 3:12 pm

Fantastic as far as I'm concerned. Everything about the TC works better as you would expect when putting really good tyres on any car.
No problem at all with rear fender clearance.
Charlie
IMG_1232.JPG

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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Sun Apr 07, 2024 4:32 pm

Thanks for posting the pic Charlie. Also, Rob Reilly says in another thread that the section width of a mounted and inflated American Classic radial in the model A size 475/500-19 is 5 inches even. The model A size tires I run have a section width of 5.2 inch and barely fit without scraping the drip rail in back. The american classic radials are something I am thinking about.

Of course the one problem of using radials is the need to de-camber the front axle. Not a small consideration.

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Steve Simmons
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Re: TC Front End Improvements-Handling

Post by Steve Simmons » Sun Apr 07, 2024 4:45 pm

It may not be that important to de-camber. Modern performance cars run quite a bit of negative camber. The only downside is the increased wear during normal driving. I have -3 degrees on both my MGA street car and my MGC track car and haven't noticed any significant side effects. Admittedly neither sees a ton of miles, but I've mostly worn out the MGC tires and they look pretty good.

I will also admit I really, really hate the look of the 19" radial tires on TCs, but on the flip side it's probably one of the biggest single improvements you could make. Better ride, handling, road noise, etc. Why can't we have the best of all worlds? ;)
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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Mon Apr 08, 2024 8:52 am

Steve, you don't like the visuals on either of the radials? The American Classic's are of a pretty conventional appearance and overall diameter, while the Bridgestones are somewhat lowish profile and a smaller overall diameter and with a flat tread.

I do know that running smaller overall diameter tires with the stock 5.125 rear end would be suicide for my engine, as I typically drive for many miles at a time in the 50-60 mph range on backroads.

I would think the Bridgestone radials would effect appearance quite a bit, while the American Classic radials would not effect appearance much at all.?

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Re: TC Front End Improvements-Handling

Post by Steve Simmons » Mon Apr 08, 2024 9:26 am

I was thinking more of the Bridgestone, which are quite small and square but offer the advantage of a completely modern tire design. I would be very interested to compare the performance of the Bridgestone to the American Classic to see how they stack up. I'm betting the Bridgestone are noticably better simply because of the mass of rubber on the AC to get that bias-ply look. But the AC is likely much better than actual bias-ply. I haven't used either one on my car, just the old venerable Dunlop B5.
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Mark Strang
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Re: TC Front End Improvements-Handling

Post by Mark Strang » Wed Apr 17, 2024 9:38 am

Steve,
I just got Millie (TC 7801)on the road and per my friends warnings, the steering is not great with a lot of wandering. I rebuilt the gear box and installed a Tompkns kit. The parts appear to be proper with a newish peg and a great worm. All clearances are correct, the toe in is at about 3/16 inch, and there is no play in any of the associated front end components. It probably is as good as it will get considering what I've done. I'm sure, the steering won't be good as on my TD's but it seems as if it could get better.
I was think about the spring loaded tie rod ends after reading your article on Heim joins. To a large degree, wouldn't a similar result, aside from strength, be accomplished by taking out most all free play in the springs save a little for the rotation of the balls in the cups? It might not help much but I don't see where it would hurt. Your thoughts?

Mark

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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Wed Apr 17, 2024 10:46 am

When setting up the BC box, an often encountered problem is with aftermarket worms that do not come through Bob G in Canada. The defective worms are not cut correctly and seem to make it impossible to do the top plate shim adjustment for center steer drag (top of sector shaft should rub slightly against top plate). In my opinion the Tomkins kit is worse than useless, and the majority of people that report good steering in a TC are using the original style flat top plate. Remember that the front plate adjustment needs to be done first, for worm end play. Then the top plate adjustment for center steer drag adjustment is done-- second.

Back in the day when people raced these cars, The TC would run circles around the rack and pinion TD.

Interesting to note that a properly made up new top plate will have a textured (crosshatched) and hard chromed surface that the top of the sector shaft will rub against at center steer. The Tomkins kit is all about reducing friction at center steer, which is all wrong.

Worn front hubs can be hard to spot. Worn front hubs will make it impossible to steer properly. The front hubs wear where the bearings fit in. The bearings may press in with seemingly normal resistance, but once pressed in there is slop from the wear. If that the case, the only way to fix worn front hubs is to replace them with brand new.

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Re: TC Front End Improvements-Handling

Post by stephen stierman » Thu Apr 18, 2024 3:16 am

Before you go to all the trouble of changing this and that, set the toe in to 1/2" as the prewar cars were set. I did so years ago and it was transformational.

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Re: TC Front End Improvements-Handling

Post by EdCallo » Thu Apr 18, 2024 5:09 am

What do you mean "when people raced these cars"?. Last night I loaded the red car in the trailer for the May Lime Rock event

Ed

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Re: TC Front End Improvements-Handling

Post by EdCallo » Thu Apr 18, 2024 5:09 am

What do you mean "when people raced these cars"?. Last night I loaded the red car in the trailer for the May Lime Rock event. And the TC still runs circles around most TD's (it is a lighter car after all with the same motor)

Ed

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Duncan M
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Re: TC Front End Improvements-Handling

Post by Duncan M » Thu Apr 18, 2024 7:43 am

Ed-
Back when almost everybody was racing them, either in stock street form or modified racing form. Much quicker steering with the BC steering box.

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