Spitfire 1979 Triumph Spitfire 1500 rear wheel alignment

[timtucker]

Howdy, just joined so this would be my first post. I have a 1979 Triumph Spitfire 1500 with 42000 miles on it. I noticed the rear wheels are angling in at the top at a good 20 to 30 degrees and that there is wear on the inside tread. When I put it up on the lift the wheels (rear only) angle outwards at the top. One person suggested it just needs new shocks, but I'm not sure that is the answer. Anyone have an answer for me on this? Thank you

 

[Trevor Triumph]

Could be shocks, but consider the spring. The usual suspects have replacements. There are shops that can re-arch the spring, too. Another thought is that if the car was raced/ autocrossed the owner may have adjusted the spring to provide that kind of camber. Most times, however, the camber is a matter of a few degrees, not twenty. Some drivers have used air shocks to eliminate the camber, but air shocks tend to cause stress fractures in the body and hence stress cracks in the gas tank.

Welcome to the site. There are a lot of people that know a lot about a lot! In others words, not just British cars.

T.T.

 

[timtucker]

thank you for the input...i will try to find a local shop that can check the spring arch......i did notice shimms placed on the spring arch (at least I think thats what they are) I may replace the shocks first just in case they look original

 

[luke44]

Shocks are not the problem, save your money.

I raced a Spit (ultimately being very successful at it) for several years, and can speak fairly knowledgeably about what you are seeing. The Spit rear end is a simple swing axle design, which has a lot of inherent design flaws. (early Corvair anyone?). The simple and best fix is to increase the static rear negative camber (exactly what you have).

The early standard race setup was to increase the negative rear camber (so the wheels would angle inward and are closer together at the top than the bottom) to prevent rollover and rear wheel lift under hard cornering. (the wheel would literally tuck in under itself going over to major positive camber - the same thing you see when the car is on a lift). To prevent this going too far in under load, a camber compensator - a flat bar, was also then attached below the diff to the 2 uprights, limiting the amount of tuck under. All in all, a bad design and a compromise fix.

Later designs (like your 1500) used a significantly modified spring which achieved the same result, but was much more reliable (and cheaper for Triumph).

The static sitting position of this is exactly what you are seeing.

Under load, this negative camber does flatten out, and in cornering it all works to the put maximum flat tire contact patch on the road. My guess, like TT noted, is the arc of the spring was adjusted a bit more - perhaps for auto crossing or just spirited driving.

While tire wear on the inside may increase, it may be nothing more than normal wear, and trying to fix this will likely decrease the handling - so it's a big trade-off - the remedy may be worse than the disease. if it were mine, I'd live with it and thank the previous owner for fixing this design flaw. Buy some new tires, don't worry about the wear, and enjoy your sporty setup.

Here's a shot of my early car in a hard right turn - what it can look like if not dealt with properly...

Here's a small picture of what can happen if you don't live with the negative camber you have now and go too far the other way...

The only other adjustment to check is rear toe - this is adjusted with shims where the upright "radius" rod mounts to the body. But this rarely needs adjustment unless the car gets hit.

You may want to check out these links as well. A picture of a Herald (same car underneath as a Spit) also really showing the point I'm making.

https://herald-tips-tricks.wikidot.com/rear-suspension:jacking-and-tuck-under

https://www.fairpoint.net/~herald948/database/cc/

Good luck with it, and welcome aboard. The Spit is a great little car.

 

[timtucker]

WOW!~ thats a relief! it handles great! and I was just worried when someone brought it to my attention. Love the little red devil and it all documented etc....42K miles is minimal and I even have the hard top for it. Thanks for your input and I feel much better now! The interior tire wear is minimal and I just didnt want to make a matter worse by driving it if it was in trouble. Will be posting other issues I have found very soon......Like the durn seatbelt buzzer that wont shut off???