i understand you now, i think the main reason you’re confused is because with a regular 5 link rear end coil spring there is no preload adjustment, as there is with coilovers and torsion bars. the reason there are not many different torsion bars is because front end weight on a built vs stock vehicle is not a very large percentage on such a heavy car, in comparison to like a 4runner where you might double the weight on the front wheels and need to double your spring rate.
100 Series long travel kit (1 Viewer)
- Thread starter Delta VS
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I believe that you completely miss my thoughts on the 100 series torsion bars, the difference between AHC, OE (non-AHC), OME, and all the other 32mm torsion bars, which are huge steps, with very little tuning in-between, for a vehicle that you’re typically adding a small amount (percentage wise) on the front suspension. It is my understanding that preload on the torsion bars does not change the spring rate, but their diameter has a significant change on spring rate.
I have a stack of 32mm torsion bars in the garage, that I’ll give you a really good deal on.
Experiment for yourself. Try AHC/OE/OME/32mm SAW, IM, TD, or Dobinsons at the same lift height (I have).
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ok, i understand you now. i know there we were nearing the limit of the front ahc protrusion bars when the system started to fail. and yeah diameter has a way bigger part in actual general stiffness than adding preload, but you need to remember that springs are progressive, even when you twist them so, although 200lb/in may sound linear but it is compounding, on our upgraded dobinsons torsion bars they do get softer and spongier when you loosen the preload off and mainly get stiffer/ not adding ride height.
One of the typical complaints about torsion bars, is that they are linear (unless they are tapered). Do you have an authoritative source, that describes a constant diameter torsion bar as “progressive”?
Could your anecdotal evidence possibly have anything to do with the change in droop?
Yep, I went through college/school of engineering ~40 years ago, and have dealt with torsion bars on multiple platforms for nearly as long (not professionally). I believe that there are flaws in your logic.
alright, is there a way you can explain the math then? What engineering? im only 18 and just finished my first year of school, and this stuff fascinates me, i think instead of debating this, it might be your place in the community as an already graduated engineer to give insight on more complex topics.
I am also working on calculating rsi numbers, dont know if any of you still have 100s and know what your rsi is/was
.Many more videos and pictures on @landcruiser_100 on Instagram
I’m in the middle of retiring, packing up, and moving. Maybe when the dust settles, and I’m not limited to just posting through a phone.
Nowadays there are plenty of resources on the Internet, and the Toyota 100 series is not unique in its use of torsion bars in vehicle suspension.
Without the math portion. Torsion bars are just coil springs that are straightened out. The twisting motion on the bar is the same as the compression of a coil spring. By turning the adjustment bolt you are simply changing the preload on the spring, not adding any more weight. So you’re really not twisting the bar any more than stock ride height. It is the equivalent of changing the installed height of a coil spring. If you were to draw a straight line on the the bar, and adjust the ride height to any position that you’d like, without reaching the end of suspension travel, the line would still be the same (same amount of rotation, or “twist” in the torsion bar”) regardless of ride height. The “harshness” that most people associate with lifting a torsion bar suspension, by turning the adjustment bolt, is typically caused by a now limited amount of droop, because of where the suspension sits at rest, in its range of travel.
Typical complaints about torsion bars are that they are linear, and unable to really do “dual rate” or “progressive rate” (tapered) torsion bars. By the method that a torsion bar is installed, you’re pretty much dealing with a “fixed length” for your application, leaving diameter as the only real spring variable (assuming solid steel).
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ok, the last part makes a ton of sense, i’ve thought about the twisting of a coil spring basically being an extremely long torsion bar. do you know what any of the land cruiser torsion bar spring rates are? in lbs/degree theta, or lbs/in? also haw many degrees does a typical coil spring twist such as a ome2863 when compressed? it must be twisting more degrees because of the thinner diameter?
I played with calculating approximate torsion bar spring rates, when I was figuring out “which torsion bar” for the 3 different 100 series in my driveway, after mixed results with 3 different “off the shelf” kits. All of that info is sitting on a desktop computer that is currently packed. At the time I was really less concerned with an actual precise number, and more interested in comparing the increase above OE for the different aftermarket options.
You might find this interesting:
Torsion Bar Wheel Rate Calculator - Sway-A-Way | Racing Technology
Available on this page are a useful chart and calculator for anyone looking to determine their torsion bars equivalent wheel rate. Wheel rate is the spring rate of a theoretical spring attached directly above your wheel. Identical to spring rate, wheel rate is measured in lbs/in. To keep our...
web.archive.org
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what....no triple "S's"?
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For all of those interested, I have been talking to Chris at KOR about doing a coilover conversion on my 2004 100 series. KOR is still in business, and he is still doing these conversion on the 100 series but has not been marketing the product at all.
See below for the quote.
Total Chaos UCAs: $840
KOR LCA and Shock Mounts: $2,950
KOR Fab Diff Drop Kit: $350 (I have a Slee one, so don't need this)
Bump Cans and Mounting Plates: $250
King 2.0 x 2 Bump Stops: $535
King Shocks: $2,250
Total Parts: $7,715
(+) Labor for Installation: $3,500
Total Parts + Labor: $10,675
Given the price, I am debating working with a shop in Southern California to make a RCLT HD-type kit for the 100 series, as it will not cost that much more than this (custom fab would obviously be more expensive, but the performance improvements would be significant for the incremental cost vs. the KOR kit).
See below for the quote.
Total Chaos UCAs: $840
KOR LCA and Shock Mounts: $2,950
KOR Fab Diff Drop Kit: $350 (I have a Slee one, so don't need this)
Bump Cans and Mounting Plates: $250
King 2.0 x 2 Bump Stops: $535
King Shocks: $2,250
Total Parts: $7,715
(+) Labor for Installation: $3,500
Total Parts + Labor: $10,675
Given the price, I am debating working with a shop in Southern California to make a RCLT HD-type kit for the 100 series, as it will not cost that much more than this (custom fab would obviously be more expensive, but the performance improvements would be significant for the incremental cost vs. the KOR kit).
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I know I am two years late to replying here, but the KOR kit is $10k. See my recent comment on the pricing that was quoted to me this week from KOR.
Cheap, right?!
My eye roll was more toward the weenie that started the thread and tucked tail and hid.
I hear you.
I am no business genius, but I don’t think it’s reasonable to ask the person who is providing a vehicle to help develop a product to pay for all the R&D, for the company to then turn around and make a bunch of money off the kit. I was emailing with Delta and would be willing to provide my vehicle, but I’m not going to pay all the upfront R&D cost on their kit.
