I need to get the corner weights on the Dirtball, so I can start working out the coilover spring rates. I am having trouble finding someone with race scales I cam use.
I have been researching the DIY bathroom scale methods and the question I have for the hive:
Pros/cons (mostly conns) of weighing one wheel at a time?
Very slow and tedious. That's all I can think of. Make sure you have pads the same height as your scale under the other three wheels.
You know, being a cheapskate at heart, I tried and tried to find a cheap way out of it and couldn't. Every alternative has enough variation (read: inaccuracy) and PITA factor that my brother and I split the cost of real corner scales.
Just buy a set and rent out to friends who need them, too. I bought these ones for just $685 and love them http://a.co/aMg6Uan
It's definitely worth it if you can spend the money on them. Spend some time to make absolutely sure you have every single scale leveled with respect to all the others. Even a tiny fraction of an inch higher on one scale can move a bunch of weight to the other corners and the stiffer the springs/swaybars are the greater the effect it has.
Disconnect sway bars before corner weighting a car
In reply to loosecannon :
re sway bars, I have heard that before, but assuming the floor is level, I am having trouble picturing what difference it could make.
Michael
In reply to loosecannon :
Assuming they're adjustable. If not it's better to leave them connected, since you probably won't be driving with them disconnected. If they are adjustable then yes, you should disconnect and readjust the endlinks so they slip right in after everything else is adjusted.
Anecdotally, on my S2000 with coilovers, when I still had the factory swaybars I could literally disconnect them while on the scales and it made absolutely no difference to the corner weights. Other cars could easily have different results though.
I made a DIY setup a long time ago with 350lb bathroom scales - 2 per corner with a board across them. Need to use mechanical scales, the digital ones have a set sequence and time out that won't work for this application.
The repeatability was not good, and it was very difficult to read the dials esp since one was under the car because I didn't have space in my garage to set up ruggles scales. Wound up giving up on that and buying a set of scales like mentioned above.
If you had a reliable, readable scale and some 2X12's for the car to sit on and allow you to roll on and off easily at each corner, measuring a single wheel at a time would not be too bad. If you have to jack the car up and down between each wheel measurement, I think it would be too tedious and time consuming.
I do have a load cell with max 1250 lb limit that you could have for very reasonable money if it's useful to you. Would need a DAC module to hook it up to a PC to get readings - so its own little project before it's useful. LMK if interested.
Thank you for the replies.
I had an a person located that had a set of scales I could use... but I have not got them to respond now. Also I can't justify the money to buy my own.
Right now I am looking for more of a ball park figure, so I can get a spring rate range and give that to the shock manufacturer. The ones I am looking at are adjustable and re-valveable, so I think right now I have a pretty wide target.
Added in the complication that I am not going to get the new chassis done for this season and I am going to have to make them work with the current suspension system. (AKA it's all going to change again later).
I just need someplace to start, so I can get the ball rolling. But personal experience is what I was looking for!
Having the sways connected can hide bad corner weights which will reveal itself as asymmetrical handling. Definitely disconnect them for set up. Once you're set up, they shouldn't make any difference once you reconnect them. In fact, that's the time you set your adjustable end links - do the corner balancing, then adjust the end links so there's no preload on them.
If you're just trying to get front/rear weights so you can rough in spring rates, then life is much simpler.
In reply to Madhatr :
Have any grain elevators or truck stops nearby that would let you use their scales? If the approach is level you could do one wheel at a time, front, rear, then total. It might not all add up to the total, but it should get you in the ballpark.
I found the bars to be unequal on my ZX2SR with non adjustable links, a little shimming evened things up.
By taking weight off the left front, lite battery, things evened out pretty good. Cross weight was very good.
Be sure to have the driver, or equivalent weight in the drivers seat.
In reply to Keith Tanner :
Thank you again for sharing your knowledge.
Yes, I am just trying to ball park spring rates right now so I can get them ordered and start fabricating brackets. Once the new chassis done and I really want to dial everything in, actual corner scales will be the ticket.
In reply to Pete Gossett :
That idea was tossed around last night, however I have some experience with that and I have questions about the accuracy. I think I have a plan we might try this weekend... gotta see if it will be an epic fail or not 
If just ball park is all you're after, go to a truck stop and weigh one end of your car at a time. It will be accurate enough to tell you axle weight and you can pick the right springs from that.
There have been a few lo-buck attempts to sell products that allegedly do corner weighing for cheap, but they just aren't accurate. Even a 1/16" error when working with 320 lb springs is 20 pounds.
I bought a pair of inexpensive $30 electronic 400lb scales from amazon. Made 3:1 lever arms to get capacity to weigh one end of the car at a time. Ramps to roll the car onto the lever arms. The scales remain on for 5 minutes. I made sure the lever fulcrum dimensions were precise by screwing a piece of 1” conduit in line with the center of the tire to carry the car weight. I use a cube laser level to set all 4 wheel pads to within 1mm. If you’re careful leveling (expensive scales won’t level themselves either), you can get repeatable results.
loosecannon said:Just buy a set and rent out to friends who need them, too. I bought these ones for just $685 and love them http://a.co/aMg6Uan
BTW how are those Proform scales? They're a good chunk cheaper than the established names.
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