Tender/Helper Springs, necessary or not?
12-30-2009, 04:09 PM
#16
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The springs unseat because the damper "droop" has not been set correctly for your spring package, or you've not selected springs that will work within the damper travel.
I've not really seen helper springs on a well set up car, and am not sure why you need them if you've used the correct springs and set the droop correctly.
The tender springs are used to change the spring rate of the suspension during the initial compression of the damper. They should be collapsed when the vehicle is at rest and I use springs that are proprotional to the weight distribution of the vehicle, so in a 911, the rear tender springs have a higher spring rate than the front. I generally have to change the droop limiters in the dampers for the individual car I'm working with.
I've not really seen helper springs on a well set up car, and am not sure why you need them if you've used the correct springs and set the droop correctly.
The tender springs are used to change the spring rate of the suspension during the initial compression of the damper. They should be collapsed when the vehicle is at rest and I use springs that are proprotional to the weight distribution of the vehicle, so in a 911, the rear tender springs have a higher spring rate than the front. I generally have to change the droop limiters in the dampers for the individual car I'm working with.
What is the purpose if the Tenders are collapsed at rest? How is that different than a Helper which pretty much does the same thing and only expands under droop conditions?
I understand now why people put helpers, but why put tenders instead if they in effect are doing the same thing. If they are compressed at rest, then they certainly aren't doing anything under cornering loads.
Seems like they may help absorb some bumps on bumpy tracks, but that's about it.
12-30-2009, 04:22 PM
#17
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What is the purpose if the Tenders are collapsed at rest? How is that different than a Helper which pretty much does the same thing and only expands under droop conditions?
I understand now why people put helpers, but why put tenders instead if they in effect are doing the same thing. If they are compressed at rest, then they certainly aren't doing anything under cornering loads.
Seems like they may help absorb some bumps on bumpy tracks, but that's about it.
I understand now why people put helpers, but why put tenders instead if they in effect are doing the same thing. If they are compressed at rest, then they certainly aren't doing anything under cornering loads.
Seems like they may help absorb some bumps on bumpy tracks, but that's about it.
A helper is a working spring that has remaining travel when the car is in it's static position. It is there to solve a problem - generally this is a problem with suspension geometry that messes up the wheel rate.
If these terms do not make sense to you, let me know and I will further explain.
12-30-2009, 04:27 PM
#18
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Tender springs have magnified effect as spring rates rise. You typically do not see or need them with rates below 600 lbs/in. As rates increase, the amount of suspension movement decreases and the unloading (and complete loss of grip) of inside wheels becomes more digital; on-off. Properly sized tender springs will help to smooth out that transition; making it more gradual because you still maintain some spring pressure on the unloaded tire. It is also more effective when you run softer sway bars as typical with very stiff main springs. Tender springs should be sized to be just barely collapsed at rest.
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2016 Ford Transit Connect Titanium LWB
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Retired Club Racer & National PCA Instructor
Past Flames:
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1974 914/4 2.0 Track Car
CLICK HERE to see some of my ancient racing videos.
12-30-2009, 04:45 PM
#19
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Doesn't seem like there is much open knowledge on the necessity of these units. I know that a lot of race cars have tenders, and many have helpers, sometimes it's hard to tell which is which, but from the conversations I've had, I know people are running both.
The question is WHY one vs the other, or what is the penalty for running neither other than noises?
The question is WHY one vs the other, or what is the penalty for running neither other than noises?
12-30-2009, 04:45 PM
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Ok, now we're getting somewhere. Thanks SD and Larry.
I just needed to justify the expense. I do not buy anything that I don't know the specific purpose for or benefit of.
So tenders are the best route then for a track car, so now comes the tuning part, how do you determine the proper rate of the tender springs for your car? I see many are in the 150 - 250 lbs range.
I just needed to justify the expense. I do not buy anything that I don't know the specific purpose for or benefit of.
So tenders are the best route then for a track car, so now comes the tuning part, how do you determine the proper rate of the tender springs for your car? I see many are in the 150 - 250 lbs range.
12-30-2009, 05:03 PM
#21
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Ok, now we're getting somewhere. Thanks SD and Larry.
I just needed to justify the expense. I do not buy anything that I don't know the specific purpose for or benefit of.
So tenders are the best route then for a track car, so now comes the tuning part, how do you determine the proper rate of the tender springs for your car? I see many are in the 150 - 250 lbs range.
I just needed to justify the expense. I do not buy anything that I don't know the specific purpose for or benefit of.
So tenders are the best route then for a track car, so now comes the tuning part, how do you determine the proper rate of the tender springs for your car? I see many are in the 150 - 250 lbs range.
Peter
12-30-2009, 05:05 PM
#22
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Or like Bob says, you can call Chris and buy a setup from him. With the amount of knowledge and experience that I have, that is still what I would do.
12-30-2009, 06:08 PM
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Never a bad idea;
On light cars with stiff springs, the amount of lift in a spring that is not seated can represent a fairly sustantial weight jacking if you think of it in terms of how many turns of the seat that represents. Scares the crap out of you when they seat themselves too.
On light cars with stiff springs, the amount of lift in a spring that is not seated can represent a fairly sustantial weight jacking if you think of it in terms of how many turns of the seat that represents. Scares the crap out of you when they seat themselves too.
12-30-2009, 07:32 PM
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You need to know what the length of the spring package needs to be at designed ride height, and then the overall spring length at full droop. This is based in part upon the shocks that you pick. Calculate the amount of compression of the main springs, and the compressed length (stack height) of the tenders to fit the length required at ride height, and then pick and adjust the uncompressed tender length to be long enough to keep the springs in their perches under full droop.
Or like Bob says, you can call Chris and buy a setup from him. With the amount of knowledge and experience that I have, that is still what I would do.
Or like Bob says, you can call Chris and buy a setup from him. With the amount of knowledge and experience that I have, that is still what I would do.
Interesting, how does he determine all of these things without the car present.
What's his information, maybe I can pick his brain.
Thanks
12-30-2009, 09:48 PM
#25
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You can find Chris on the forum here. Spline Technologies is his company. Please take a reasonable approach to picking someone's brain that is trying to make a living. I am sure if you ask him some questions you will realize he knows what he is talking about. The one thing he cannot assess over the phone or via email is one's ability. The more responsive the suspension, the more on top of it you must be. I have had two coaching sessions with Chris and after driving with him you realize why he has track records. After only two 20min sessions with Chris in Oct, I was .7 secs off the track record for my class on old practice tires.
12-31-2009, 04:46 AM
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thats why I took it to him to set up. I would not know the differance at all. All I know is there are two springs under there not just one main spring...As far as spring rates, no clue either. I could look at the numbers on them but would have no Idea what they mean. when I need advice I just call up Chris and we work it out. Have had no complaints on my setup. even still works very well after dropping 400 plus pounds off the car. Car feels very stiff with out bouncing all over the place like I see some cars doing. Its just right...
sorry not much help. I do a lot of work on my car but suspension is his job...
12-31-2009, 09:40 AM
#27
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