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Buggy Front Suspension
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1600buggy
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PostPosted: Wed Jun 03, 2015 9:25 pm    Post subject: Buggy Front Suspension Reply with quote

Ive been doing a lot of reading on softening up a stock torsion bar setup for fiberglass buggies.I have my own bars out now and one of the thin "slats" on each side of each bar is broken at the end. I cant buy just the small ones to replace so now i am wondering if I can cut them except where the grub screws go or if that will be to weak or prone to failure. Another option for me is to replace the two small ones with one big one. What was the original purpose of the thinner ones? Any suggestions would be greatly appreciated.

I will be having a beetle gas tank in the front adding weight.
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BL3Manx
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PostPosted: Wed Jun 03, 2015 11:27 pm    Post subject: Re: Buggy Front Suspension Reply with quote

1600buggy wrote:
.I have my own bars out now and one of the thin "slats" on each side of each bar is broken at the end. I cant buy just the small ones to replace so now i am wondering if I can cut them except where the grub screws go or if that will be to weak or prone to failure. Another option for me is to replace the two small ones with one big one. What was the original purpose of the thinner ones? Any suggestions would be greatly appreciated.


Just to clarify terms and make things a bit easier to follow, most people call each of the front torsion spring packs a "stack of leaves". The stacks are made up of wide leaves and narrow leaves. When you say "on each side of each bar", I think you mean on the top and the bottom of a stack.

You can cut either the narrow or wide leaves but like in the picture you copied you must use sections of the cut leaves to make the stack square where it fits into the anchor in the center and into each trailing arm.

Its very important that the stacks aren't flipped end for end, put paint on one end of all the leaves. Torsion leaves take a set and if they are reassembled and put under load backwards they will break.

The cut sections you put back on must be bonded in place so they can be slid into the anchor and trailing arm. Use solvent to degrease the leaves and use JB Weld and clamps to attach the cut sections to the leaves below.
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Dale M.
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PostPosted: Thu Jun 04, 2015 6:11 am    Post subject: Reply with quote

The narrow leaves give a softer more desire front "spring rate" over front leave stack the is all wide leaves...

Replacing a pair of narrow leaves with one wide leaf will change ride characteristics, usually wider leave is stiffer so it will probably make front end stiffer and that is probably wrong direction.... Usually softening front end (cutting leaves) is more desirable to compensate for the removed weight of steel body when chassis was converted to a buggy body.... 99% of the time you want to soften front end of FG buggy for 99% of its intended driving...

Dale
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didget69
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PostPosted: Thu Jun 04, 2015 9:36 am    Post subject: Reply with quote

I KNEW I should have Copyrighted that drawing... Laughing

bnc
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1600buggy
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PostPosted: Thu Jun 04, 2015 9:50 am    Post subject: Reply with quote

Yes you are right with all my terms. That's just what I think of them as. When I pulled them out they had a small VW logo stamped on the passenger side so thats what I used to keep them correct.

Will cutting the leaves affect durability in any way and will it keep the same ride height in the end? Softer is better but I like the height it sat at before. Also should I do both tubes or just the top or just the bottom.

Thanks for the drawing by the way. It is the only one I could find and illustrates very well. Hope you don't mind my using it.
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IowaRedManx
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PostPosted: Thu Jun 04, 2015 10:28 am    Post subject: Reply with quote

When I first built a long wheelbase bug I was at a buggy event and asked why the front suspension was so stiff. I talked with 8 or 10
others about it and did not come up with a reasonable answer.

Later I was talking with an older gentleman and he explained that there is a combination of things that must be done. We went over
to my buggy and he looked around. After a couple minutes he said that everything looked OK. Keyword "looked".
Then he went on to explain that the tires were designed to go on a vehicle that weighed about 4000 pounds. My buggy weighs about 1600
pounds. He then gave me a lesson in the rating on the tires. The date they were made, the weight that were designed to carry, etc. He also
explained that most tires fail due to improper inflation. In my case the tires were each designed to carry a maximum load of 1750 pounds
each. In other words they were designed for a vehicle weighing 7000 pounds or 3.5 tons. They were also rated for 38 PSI inflation, I was
running 32 PSI.

He advised me to lower my pressures down to around 15 PSI, and if I went off road to lower the PSI to about 8. Since then we have become
very good friends and I have enjoyed a very smooth ride from the buggy, with 18PSI in the rear and 10 PSI in the front.

The phenomenon of overinflation in the buggy world is even more pronounced when we put LT rated tires on a buggy. Remember that tire
failure generally is the result of to much weight which causes an excess amount of sidewall flex while driving. When the weight of a vehicle
is drastically reduces, it is possible to utilize a much lower pressure in the tires. I am always amuse when I see people trying to do the various
procedures to modify the front end, or things like coil overs on the front of a buggy

I am also curious as to what the actual air pressure is in your tires.
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BL3Manx
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PostPosted: Thu Jun 04, 2015 3:00 pm    Post subject: Reply with quote

I agree with Iowa, lowering the front tire pressure to around 12 psi and the rear to around 15 makes a huge difference in ride quality.

One other thing all short wheel base buggies need is additional caster to improve steering stability. Adding caster shims between the lower torsion tube and the frame head often solves nasty steering issues.
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manxdavid
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PostPosted: Thu Jun 04, 2015 3:21 pm    Post subject: Reply with quote

Plus no one's mentioned dampers. Oil shocks only, no gas and no coil overs.
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Wolfgangdieter
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PostPosted: Sat Jun 06, 2015 6:05 pm    Post subject: Reply with quote

So if one is broken - cut end pieces and a center piece off and tack weld it to outer wide leaf. I do same on one on the other side of same pack too. I'd try that on road - if still too stiff do same to the other stack of leaves. Since you have so little weight in front you don't need them all.
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Dale M.
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PostPosted: Sun Jun 07, 2015 6:42 am    Post subject: Reply with quote

Once one finds the right combination of leaves in torsion leaf pack, and is still not happy with ride height, one might want to consider a adjustable center section in beams, I went with new set of beams with avis adjusters and I actually set it "statically" during build and I am so happy with height/stance and handling I have never changed it and the build was more then 12 years ago...

And as someone else mentioned no gas shocks, minimal oil (only) shocks are more then enough...

Dale
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
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1600buggy
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PostPosted: Tue Jun 16, 2015 6:26 pm    Post subject: Reply with quote

thanks for the thoughts guys. i am in the process of building/restoring the buggy, never actually driven it but i had never thought about tire pressures. definitely something to play with. i had thought about adjusters but figured id get it together and install them later if need be. I have new oil shocks for it already and caster shims in the online cart. I will cut them like in the picture and see how it rides sometime in the future. if i can get away with doing only one tube first should it be the top or bottom or just do both???

thanks again guys, you are a huge help
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BL3Manx
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PostPosted: Tue Jun 16, 2015 6:52 pm    Post subject: Reply with quote

1600buggy wrote:
I will cut them like in the picture and see how it rides sometime in the future. if i can get away with doing only one tube first should it be the top or bottom or just do both???


Yes, you can do just one stack. I think there are 10 leaves total, some wide and some are a pair of narrow ones(side by side). Each leaf you cut is an approximate 10% reduction in the spring rate.

If you try it out and decide to cut additional leaves, it will be a bit more work in the end, but probably worth it to proceed slowly. You can't un-cut a leaf.
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