sunbeamtiger.co.uk

I am seriously considering having a go at fabricating a set of caltrac type of anti-tramp bars for my Tiger. I understand some of the guys in the UK use them on their racing Tigers. Does anyone recall seeing pictures of them on the forum they could point out to me?

I am told they might hang down a bit too low for general driving ground clearance comfort. I would like to see what they actually look like on a Tiger. I have some as yet unmounted bolt-on Traction Masters which also will obviously hang down at the axle. So maybe the caltracs will not be any worse in that regard, and will work better.

It would also be helpful to see how big the bell crank plates are and where the bar across the top of the leaf spring is positioned. The regular guidance is to put it half way between the spring eyelet and the beginning edge of the second leaf. As you know, the second spring leaf is very close to the front eyelet!

I have been told it is helpful to remove one of the leafs for racing purposes to soften the rear and get the car to squat, aiding weight transfer under acceleration. I am thinking about giving that a try. Do the UK racing guys do that and if so which leaf do they take out? I am thinking about taking out the second leaf in conjunction with the caltrac mounting. But maybe having the caltrac working off of first and second leaves together would be better since they are a bit thin!

Rather than reinventing the wheel so to speak, thought I would consult with you guys first. Thanks in advance for any and all help!

Cheers, Gene

Hi Gene,

Here is a link that I found which shows a picture of one connected to a leaf spring. http://www.calvertracing.com/caltracs.php
Is it because the Caltracs are adjustable that you like their design better? I ask this as traction master already have a kit for the Tiger (weld-on or bolt-on). I do like the way Caltrac have design their rear mounting bracket though ( a bit more rigid than the T M's). To me it looks like the Caltrac bars may sit down a bit lower as well.

Regards, Robin.

Robin, I do have a set of the bolt on Traction Masters, but have not tried them yet.

The caltrac design is said to be much better. The axle is going to twist in the opposite way of wheel motion. Under acceleration the left hand side wheel will want to rotate counterclockwise and the axle clockwise as you look at it. That axle rotation will put upward force on the front half of the spring. This will tend to distort the main leaf allowing axle rotation as the pinion tries to climb the crown gear due to engine torque, etc. The caltrac converts that upward bending motion into a downward force against the top of the main leaf at the weakest point. That counteracts the upward force, keeping the spring from distorting, preventing wrap up, etc. The Traction Master bolt ons add ridgidity but it is pressing up on the spring instead of down, just at a stronger point. It also compromises the spring rate, which the caltrac does not. The weld ons are well know for transferring that rotational force to their welded on bracket, ultimately tearing it off the chassis. Plus they take out the front part of the spring function because the move in a different arc. The leaf spring can elongate and contract in length as it flexes. That is why they have the swing shackle at the back. Traction Masters don't. The caltracs do not interfere with that. Or so I have been lead to believe. Hence my strong interest. BTW, I am also soon putting in a 347, giving rise to my interest in all of this!

Cheers, Gene

You certainly do your homework Gene. I agree the Caltrac's look a lot more purposeful and designed around strength, hence the cost difference. The ability to adjust them is also a great idea.

Here's a rear axle video link that was posted on a healey forum, it shows the axle and spring motion under load fairly well. Big Healey, so not quite the same, but similar. Quite a range of motion.

http://www.youtube.com/watch?v=tN-4LLAK ... e=youtu.be

taken from: http://healey.hyperboards.com/action/vi ... ic_id/2828

Brilliant vid Wilbur! It's amazing to see how much "flex" the rear axle suffers. That Healey wasn't hanging around

Hopefully my specialist is reading this thread and he can fit a pair of Caltrac's next time my Tiger is in for a service

Tomaselli wrote:Hopefully my SPECIALIST is reading this thread and he can fit a pair of Caltrac's next time my Tiger is in for a service

that word keeps cropping up

Wilber, if a picture is worth a thousand words, that video must be worth in the millions.

Do the Healeys have a lever shock on the axle or is that arm below it some sort of suspension link? Whatever that arm is, it is certainly doing a big job of controlling axle rotation and consequent spring wrapup. I cannot imagine what the distortion of the spring would look like without it. As would be the case with a stock Tiger...

This Healey video makes me all that much more interested in seeing a caltrac type mechanism on a Tiger. Any guys on this forum that race their Tigers have any to share?

Cheers, Gene

It would be nice to see a before and after video showing the advantage in fitting tramp bars. Thanks for the video Wilber.

tigerguy2 wrote:Do the Healeys have a lever shock on the axle or is that arm below it some sort of suspension link?

Yes, standard Austin-Healeys have your basic Armstrong lever shock combined with a small other bushed link from end of lever to the rear axle mounting point.

bushed link looks like this: http://www.ahead4healeys.co.uk/SHOCK-LINK-id3791.html

Wish I could post a picture of my cal-trac setup, they really do work and i still use the back bracket of the old traction bar steup so they don't sit any lower thaen the stock traction bars. I still run a stock type spring, they only problem is I broke a couple of leaf spring right up by the front eylet but I really abuse my setup by drag racing it all the time and leaving off a trans brake

Twin Turbo

It would be good if you could post up a pic. They obviously work well and been well tested. If you can't post pic's you could email them to me,
and i will post them to the topic.

Cheers Mal