[Tigers] Front suspension

Fri Oct 1 18:31:41 MDT 2021

Buck, thanks for chiming in. I totally forgot to mention the bump steer issue, that is a great story re: Mike Jones. Take careMike

-----Original Message-----
From: Buck Trippel <bucktrippel at verizon.net>
To: 'Michael Wood' <mwood24020 at aol.com>; garywinblad at comcast.net; blance598 at gmail.com
Cc: tigers at autox.team.net
Sent: Fri, Oct 1, 2021 11:00 am
Subject: RE: [Tigers] Front suspension

I have a lot on my plate right now so this will have to be brief. I’m replying to Mike’s earlier post and not Jim’s mods.

In Mike Jones’ talk a few weeks ago at SUNI he described some of the challenges that he, Kevin Beattie and the Rootes engineers encountered when they put the Tiger into production. He mentioned that they knew that the rack position made anti-Ackerman an inevitable problem, but they were under a deadline to put the car into immediate production. They did design a MK2 version would have larger 14”wheels which could accommodate longer steering arms to lessen the problem as well as the larger 3-puck Girling brake package used on the Cobras and Austin Martins on all corners. But by the time the Mk2 was produced these were eliminated and only Mike’s relocation of the Panhard bar mount survived, chassis-wise.

So we all know the Tiger’s Ackerman is terrible. It also suffers from a complete lack of camber gain. And its bump steer is horrendous. (We’ve carefully measured all of them.) One discovery that prompted a chuckle was that when the Tiger takes a set in a hard turn the bump steer is so bad it actually corrects some of the Ackerman problems. I pointed this out to Mike and expected him to identify an engineer who came up with this entirely creative band-aid but instead he said he was sure it was completely unintentional. That immediately let the air out of my balloon.

As far as aftermarket fixes, Dale’s numbers look great for ackerman, camber gain and bump steer. I’ve driven Tigers with Hokansen’s mod and they drive nice but I never have seen his numbers.

As far as mods to the stock suspension, the main problem for me is Camber gain. When the chassis rolls it rotates the inside of the tire patches off the pavement. Any real fix needs the ball joints to be an inch or two further apart. The Tiger spindle weighs half what a Pinto’s does. It’s flimsy in comparison. We have seen enough flexing on the race track that I have been scared to space the ball joints further apart. We built a spaced a setup and did a one-day test with it at Willow and it worked but it now sits on the shelf due to my reluctance to take on more risk.  MG arms take a little of the problem away as does milling off the “feet” on the rack but the aftermarket solution of putting the rack under the motor addresses all those problems. I think Dale is still selling his replacement crossmember front suspension but I suspect they will now cost you more than $5K.

As to the electric power steering from Europe, I’ve installed and tested it. It’s fine around town and on twisty roads however I can’t get enough caster into a Tiger to make it reasonable to use on the open road. It has too much friction for our cars to overcome it and track straight on the highway. You have correct constantly. For an hour or two that’s OK. It’s so much work that an 8 or 10 hour cross country day became impossible for me. So it now also sets on a shelf in the garage. I’m expanding the garage.

Buck Trippel 

From: Tigers <tigers-bounces at autox.team.net> On Behalf Of Michael Wood via Tigers
Sent: Friday, October 1, 2021 9:37 AM
To: garywinblad at comcast.net; blance598 at gmail.com; tigers at autox.team.net
Subject: Re: [Tigers] Front suspension

I'm far from expert...maybe a layman open to experimenting lol 

I think a lot of guys building Mustangs, Camaros etc still do the Shelby drop (relocating the upper control arm downwards). But, I don't know how it would work on a Tiger, as we run into control arm clearance to unibody issues pretty quickly at the fastener to the rear (if you follow what I'm saying) when shimming for negative camber. That clearance becomes even less when you start looking at dropping the physical location of the UCA. So, the question would be whether the negative camber gained in drop would offset the loss of ability to shim, I guess. But, yeah, the camber curve should improve. 

Wonder if anyone has done it?

Mike

-----Original Message-----
From: GARY WINBLAD <garywinblad at comcast.net>
To: Michael Wood <mwood24020 at aol.com>; blance598 at gmail.com <blance598 at gmail.com>; tigers at autox.team.net <tigers at autox.team.net>
Sent: Fri, Oct 1, 2021 9:23 am
Subject: Re: [Tigers] Front suspension

Mike, 

Thanks for your expert analysis! 

Yes, I never did find what Ackerman is best either..  I heard Doane speak and he said the reverse Ackerman is actually an advantage when you are 

countersteering (what I think he meant).  I wrote a program to figure out how it works on the Tiger.  Turns out Ackerman is not really that bad until 

you get to pretty extreme steering angles, so on a big track it isn't really that bad.  And with initial toe-out dialed in it might not be that bad on a really 

tight course.  And because of the fulcrum pin issue, I NEVER go full lock anymore, even parking. 

Yeah camber... why did the lowered a-arm trick seem to work back in the day but isn't used anymore?  The GT-350s I have looked at still have it. 

I know it was bad for braking but so is initial negative camber? 

Heavy steering, why I left my big stock steering wheel. 

Gary 

On 10/01/2021 11:54 AM Michael Wood <mwood24020 at aol.com> wrote: 

Gary, I think you nailed it, reverse Ackermann leads to some funky slip angles and strangely heavy steering, particularly felt at low speeds...the front tires are literally fighting each other. The fact we all typically add wider wheels makes the steering even heavier (both contact patch to move around and scrub radius). Finally, maxing out caster with wedges (which I do) makes it even worse!  

The longer MG steering arms help, I've found on cars I've driven so equipped, but I haven't bothered to do on my car. Toe out changes the slip angle and also helps get the car to turn in, but I only go to toe out (1/4") when autocrossing, as toe out also is a great way to kill tires. Besides the poor camber curve, Ackerman is another reason why I run as much negative camber as possible...if the outside wheel isn't technically aligned to the turn radius correctly, at least I can maximize the unaligned contact patch in roll lol. Funny thing, even the real experts I've read can't seem to agree on "Ackermann", because there are so many other variables. 

I don't know, outside of a custom solution like Dale's or Hokanson's front ends, of a real fix. I've just learned to live with heavy steering, but if it really is a problem, going to stock width wheels and smaller section width tires really makes a difference. The electric power steering solution has gotten to be a pretty easy deal, but that obviously does nothing to address the underlying geometry issues. 

Mike 

-----Original Message----- 
From: GARY WINBLAD <garywinblad at comcast.net> 
To: Lance Beauchamp <blance598 at gmail.com>; Tiger List <tigers at autox.team.net> 
Sent: Fri, Oct 1, 2021 7:42 am 
Subject: Re: [Tigers] Front suspension 

Lance, 

 There are a couple more expensive solutions that might be still available. 

Dale did design and make an entire front crossmember/suspension.  It fixed the geometry but was about $5K 

last I heard, and he might have stopped making them. 

People (mostly in EU) have put in electric power steering.  It mounts up under the dash so it all looks stock, 

would be great in a parking lot or tight course.  Others have put in conventional hydraulic power steering. 

Shelby had his guys put in a Miata power rack in his wife's Tiger for instance. 

Gary 

On 10/01/2021 9:36 AM Lance Beauchamp <blance598 at gmail.com> wrote: 

So it is what it is, end of story, thank very much for a really good explanation,  still love the car. Beau  

On Thu, Sep 30, 2021, 10:13 PM GARY WINBLAD <garywinblad at comcast.net> wrote: 

HI Lance, 

Steering geometry is a real problem.  Shelby throwing the rack way out in front of the engine was a quick solution. 

Rootes didn't want to change a Shelby design... so we suffer today.  Doane knew it was a problem but he thought 

Rootes would build a new crossmember. 

The problem is when you go around a corner, the inside wheel needs to run a smaller radius turn than the outside. 

Toe in on turns or Ackerman geometry is what it is called.   The Tiger has reverse Ackerman, the inner wheel turns 

a larger radius!  When I used to push my Tiger out to my slightly downhill driveway it was easier to turn the wheel 

full lock than to reach down and pull the parking brake... what a great design Shelby! 

On a tight autocross course or a parking lot this is really less than ideal...  MIKE analysis?? 

On a big course it might not make such a difference though Jim Adams said he had to "toss the Tiger like a sprint 

car"  (keeping it jumping and sliding rather than be smooth.. I hear that as...). 

Longer MGB steering arms and initial toe-out is the small solution Dale has... 

You may notice, its hard to turn the wheel at slow speeds, especially with big sticky tires. 

But once you go into a fairly tight turn, it becomes easier as both tires lose contact.. and the Tiger goes straight 

off the corner... 

Mike, do I have it anywhere correct? 

Gary W. 

On 09/30/2021 9:55 PM Lance Beauchamp <blance598 at gmail.com> wrote: 

You say you spend alot of time on suspension Gary, can you tell me how to make the Tiger easier to turn at lower speeds, like 15 mph or under. I always  blame the steering  geometry,  is it all that?  Beau  

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