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Making my own Coilovers for my B210 with ZX struts. Few questions........


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I understand the method used for making some coil overs with sleeves and strut collars and such. But I'm unsure of what length of springs to use. (ie, 10" or 14" or other length?)


link to intended used sleeves:


link to list of spring lengths, etc



These will be going on my 76 B210 4 door. I want comfort, but good handling.


What are some recommendations for spring rate and spring length? I don't want it slammed "on its nuts" ... just lowered.




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As they are adjustable, spring length is not really important. If too short, slide the sleeve up and use split collar to secure it. If too long, just lower it. Keep in mind that a proper spring that is too long may bring it close to the side wall of the tire. 

The most important thing when selecting a spring is it's spring constant or rate. It must support the weight of the car and must allow some suspension travel so the shock absorbers can absorb the harshness, provide comfort, and prevent rebound. (bounce) Generally a stiffer spring rate than stock improves handling at the expense of comfort. Trust me stock springs are very soft so you can almost always add much more rate before it becomes uncomfortable. Spring rate and 'feel' or 'comfort' are totally subjective and what works for you doesn't work for someone else. You are going to have to try several to find what works for you.


Spring length and rate are related so shortening a spring will change the rate. All things equal a longer spring is softer than one that is shorter, a larger diameter spring is softer than a narrower spring, a thinner wire is softer than a thicker wire.



Select a coil that will fit over the sleeve without chafing and fit the top hat and the lower spring perch. Remember that a wider spring may be close to the tire side wall.


Select a spring rate suitable to your needs. A B-210??? is similar to a 510 so 175-225 lb/in. Again I'm not suggesting a rate, only you can know what works for you. I guess I would rather have one too soft that too hard. Pick something or drive in a similar car with a known rate to see if you like it. You have to start somewhere to know weather to go up or down on the rate.


Spring rate...

If you can multiply and divide, and make a few simple measurements on a spring you can work out the spring rate. Some makers can supply these measurements even if they don't publish the rate. How anyone could buy a spring without knowing the spring rate is not only crazy, it's a foolish wast of money. Know what you want, and get what you want. verify the rate. Makers can play fast and loose with numbers. If a spring seller can't supply this information go somewhere else.

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You can do this. If using split collars you don't even need the sleeves.The split collar sets the ride height.  Hell you can cut your B-210 springs down to get the correct spring rate you want  too. Try it and if stiffer is needed, just trim them more. It's one way though, once cut you can't go back. Maybe find a spare set of B-210 springs? Split collars are about $25 but you need a small angle grinder and a morning. 

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I'm more than confident that I can do it, just wanted opinions on what others have used for length and rate.


I could make it easy and just cut springs and use collars, but I'm the type to not "ruin" parts for modification purposes. I'd rather get extra ZX struts and modify them. I could get extra B210 struts, but i'd prefer larger brakes, too.


Thanks again for the help!

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If you want to keep the same ride height, but stiffer. Weight the front end, divide by two, and that's the approx. weight on each front tire/spring. Measure spring perch to spring perch, that's ride height. Jack the car up, measure spring perch to spring perch. That's your minimum free length. Calculate the spring rate of the spring currently on the car. Knowing the weight of the corner of the car, you can calculate the compression of the new higher rate spring to achieve the same compression distance to maintain the same ride height, that's where free length and wire diameter and coil diameter come in..

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Do you have any of the coil over parts? If not, take a look at Coleman machine..you can buy flat 2.5" upper spring retainers, threaded collars and lower spring platforms cheap. 10" x2.5" ID spring, you could run an 8" too, but that depends on the OAL of the insert you are using as that will play a major part in determining your droop travel. With an off the shelf 280zx insert, I would run a 10" spring...most of these cars end up with way too much droop travel. If you have a lot of it, its important to keep spring tension, and not have the spring come off either retainer or platform.

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