Spring rate?
- Thread starter PITT40
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275 is the stock rate.
Many believe the Tiger is vastly undersprung. Some believe the Tiger's early reputation as a evil handling car was do to these weak springs which allowed taking a set while on (or almost on) the bump stops, resulting in almost no suspension travel when road imperfections were encountered.
Many choose higher spring rates.
Dale sells 450 lb springs for the street and 600 (or so) for the rears. Most racers run as stiff or stiffer rates.
Dale's rear springs are also stiffer than stock.
As far as setting a car up for autocross, you might try to find the old Tiger Tales article Tom McDaniel penned maybe 10 years ago. Mike Wood would also be someone I'd consider as an expert. Maybe he'll chime in with his thoughts.
bt
at the beach
bt
at the beach
Many believe the Tiger is vastly undersprung. Some believe the Tiger's early reputation as a evil handling car was do to these weak springs which allowed taking a set while on (or almost on) the bump stops, resulting in almost no suspension travel when road imperfections were encountered.
Many choose higher spring rates.
Dale sells 450 lb springs for the street and 600 (or so) for the rears. Most racers run as stiff or stiffer rates.
Dale's rear springs are also stiffer than stock.
As far as setting a car up for autocross, you might try to find the old Tiger Tales article Tom McDaniel penned maybe 10 years ago. Mike Wood would also be someone I'd consider as an expert. Maybe he'll chime in with his thoughts.
bt
at the beach
bt
at the beach
- Messages
- 2,873
Sometimes Exact, BUT
We've actually tried to measure various springs from time-to-time. Starting from a relaxed 11-1/2" or 12" we press down thru the scale in 1" increments for readings. Oddly, they are almost never the same, and it takes a few pieces before we get a matched set. Example: 8-1/2" can vary from 325# thru 385# for new stock springs. The dirt/sprint guys next door have a 4-corner scale they let me park on once and decided that my pasta fed butt needed another 35# in the front left for true balance. Not that you can really balance the mongrel Tiger, but it did handle much better thru snug corners. I do have a "firm" set here that will lower your car about 1" and provide a stiffer feel if you want to try them.
We've actually tried to measure various springs from time-to-time. Starting from a relaxed 11-1/2" or 12" we press down thru the scale in 1" increments for readings. Oddly, they are almost never the same, and it takes a few pieces before we get a matched set. Example: 8-1/2" can vary from 325# thru 385# for new stock springs. The dirt/sprint guys next door have a 4-corner scale they let me park on once and decided that my pasta fed butt needed another 35# in the front left for true balance. Not that you can really balance the mongrel Tiger, but it did handle much better thru snug corners. I do have a "firm" set here that will lower your car about 1" and provide a stiffer feel if you want to try them.
When measuring springs, there are two parameters.
The first is spring rate. To check the rate you need two points, and the difference in load and distance give you the rate in pounds/inch.
To check the length, the height is measured at a "check load" which is picked to be near the load as it is installed in the car. Alternately, you can specify a "check height" and measure the associated load. This is done because the free length of the spring isn't a very good measure. You can have two springs that have different free lengths, but because they also have different rates, they will end up at the same length when installed on the car. It might seem like a minor difference, but it's not unusual to have at least +/- 5% on spring rate, and that can make a big difference in free length.
So-- if you are checking springs, check them at a fixed total height, not an amount of compression from free height.
I have access to a spring checker if you ever want them fully checked out.
The first is spring rate. To check the rate you need two points, and the difference in load and distance give you the rate in pounds/inch.
To check the length, the height is measured at a "check load" which is picked to be near the load as it is installed in the car. Alternately, you can specify a "check height" and measure the associated load. This is done because the free length of the spring isn't a very good measure. You can have two springs that have different free lengths, but because they also have different rates, they will end up at the same length when installed on the car. It might seem like a minor difference, but it's not unusual to have at least +/- 5% on spring rate, and that can make a big difference in free length.
So-- if you are checking springs, check them at a fixed total height, not an amount of compression from free height.
I have access to a spring checker if you ever want them fully checked out.
QC on springs can vary more than we might think. I've measured numerous sets of race springs that have had as much as 18% variance in actual rate. Hyperco and Swift are the two vendors that have consistently been best, fwiw.
My personal opinion on a no-compromise Tiger set up (using oem front suspension, including A-arm location) for autocross is pretty simple and is pretty standard for old A-arm cars with poor camber curve: lots of spring rate and lots of static camber. I think the motion ratio of the Tiger's front suspension is in the .5-.6 range, so using a simple calculation, the wheel rate of a 450# spring is in the 115-165# range. I think you could argue spring rates in the 1000# range might be indicated, to get wheel rate somewhat closer to corner weight, as a starting point. I've heard stories of racers "back in the day" running intentionally bound up front A-arm suspension and relying on the old, taller profile tires to provide spring rate to keep out of the suspension...don't know if that's true or not, though.
But, I also like to drive my Tiger on the road and not beat the crap out myself and my wife, so compromise is part of the deal. I'm currently running 450# front springs, but I cut them years ago...can't remember exactly how much and, as a result, I can't begin to figure out how much it upped rate. I also run a decent amount of camber, like -1.5 when autocrossing on street tires. I may go to 600# springs, but it isn't a priority, as I have a dedicated autocross car and want to keep the Tiger comfy.
Rear springs I'm starting to re-think. I've always believed that the rear end needed to, basically, follow along and compliance was key. So, rear spring rate in the 170-190# range seemed to make sense to me. But, I'm hearing from Buck that might be something to reconsider
One other thing: If you're going to bigger rates, I'd really suggest doing the Tom Hall mods to the front end. You'll be putting more load into the known failure points.
My personal opinion on a no-compromise Tiger set up (using oem front suspension, including A-arm location) for autocross is pretty simple and is pretty standard for old A-arm cars with poor camber curve: lots of spring rate and lots of static camber. I think the motion ratio of the Tiger's front suspension is in the .5-.6 range, so using a simple calculation, the wheel rate of a 450# spring is in the 115-165# range. I think you could argue spring rates in the 1000# range might be indicated, to get wheel rate somewhat closer to corner weight, as a starting point. I've heard stories of racers "back in the day" running intentionally bound up front A-arm suspension and relying on the old, taller profile tires to provide spring rate to keep out of the suspension...don't know if that's true or not, though.
But, I also like to drive my Tiger on the road and not beat the crap out myself and my wife, so compromise is part of the deal. I'm currently running 450# front springs, but I cut them years ago...can't remember exactly how much and, as a result, I can't begin to figure out how much it upped rate. I also run a decent amount of camber, like -1.5 when autocrossing on street tires. I may go to 600# springs, but it isn't a priority, as I have a dedicated autocross car and want to keep the Tiger comfy.
Rear springs I'm starting to re-think. I've always believed that the rear end needed to, basically, follow along and compliance was key. So, rear spring rate in the 170-190# range seemed to make sense to me. But, I'm hearing from Buck that might be something to reconsider
One other thing: If you're going to bigger rates, I'd really suggest doing the Tom Hall mods to the front end. You'll be putting more load into the known failure points.
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