Kimplex shocks

a_colo_native · May 6, 2006

Gord

Have you spoken with the manufaturer about what the specs are for thse shocks?You can not just assume that because they willbolt in,that they will function properly and safely too. This is a very dangerous situation. These are designed for a 500LB snowmobile and not a 2660+LB car. The forces exerted on them are not even close to the same. An amphicar turning a corner at 20 MPH exerts lateral forces that no snowmobile could in any situation. The weight of the car alone is~6 times what they are designed for.With hi-way speeds and and a shock that is over taxed it will fail eventually (possibly a catastrophic failure). I would not place my car and passengers at that type of risk. If you have spoke with the manufatures and they say it is safe, then we should use them. It takes more than looking the part, it must safely act the part as well.When other shockshave broken, hadhe had been going down the road at even 35MPH (or 60MPH) when it broke, people could have died or worse. The lives of your passengers depend on it. Please let me know what they have said when you speak with them. Maybe they will work just fine, we need to know forcertain before something bad happens again. Maybe they will just wear our sooner but function safely.This is just friendly concern for all of my fellow amphibians.

John Bevins

WB6WSN · May 6, 2006

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<div dir="ltr" align="left">
<blockquote style="MARGIN-RIGHT: 0px">
<div class="OutlookMessageHeader" lang="en-us" dir="ltr" align="left">From: amphicar-lovers@yahoogroups.com [mailto:amphicar-lovers@yahoogroups.com] On Behalf Of a_colo_native
Sent: Saturday, May 06, 2006 9:36 AM
To: amphicar-lovers@yahoogroups.com
Subject: [amphicar-lovers] Kimplex shocks


Gord

Have you spoken with the manufaturer about what the specs are for thse shocks?You can not just assume that because they willbolt in,that they will function properly and safely too. This is a very dangerous situation. These are designed for a 500LB snowmobile and not a 2660+LB car. The forces exerted on them are not even close to the same. An amphicar turning a corner at 20 MPH exerts lateral forces that no snowmobile could in any situation. The weight of the car alone is~6 times what they are designed for.With hi-way speeds and and a shock that is over taxed it will fail eventually (possibly a catastrophic failure). I would not place my car and passengers at that type of risk. If you have spoke with the manufatures and they say it is safe, then we should use them. It takes more than looking the part, it must safely act the part as well.When other shockshave broken, hadhe had been going down the road at even 35MPH (or 60MPH) when it broke, people could have died or worse. The lives of your passengers depend on it. Please let me know what they have said when you speak with them. Maybe they will work just fine, we need to know forcertain before something bad happens again. Maybe they will just wear our sooner but function safely.This is just friendly concern for all of my fellow amphibians.

John Bevins

</blockquote>

I agree with almost everything John says; you should always besafety conscious when second-sourcing any part, especially in the suspension area. OTOH, the Kimplex shocks may not be as under-rated as you think.

First, the manufacturer is not going to tell you a darn thing about use of his parts in anything other than what the part is marketed for. The manufacturer has too much legal exposure to risk chatting with you about possibilities.

Next, the weight issue. I think that the snowmobile uses only one shock for its 500 pound mass, while the Amphi is using 4 shocks for its 2600 pound mass.That's only a 30% greater load for the Amphi. Further, the snowmobile shock should be rated for a high duty cycle; that is, a snowmobile is always bouncing and flexing its suspension, the shock is working hard all the time. In an Amphi, the shock is not being worked hard at all (who's doing slalom courses and hard cornering in their Amphi?).

Finally, the shock carries no lateral forces at all. The swing arm constrains all front-back and left-right motion. The shock does two things; dampen the swing-arm rotation motion and provide a mount and holder for the suspension coil spring. If the shock completely fails (the dampening function), at worst you will get a bouncy ride. If the shock fails (in its spring holding function), then things get much worse. Probably the worst shock failure would be if the upper or lower bushing eye broke off of the shock body or extension rod. The ride-height would drop, the tire would likely hit the wheel well, directional control would be very tough, the loose shock could flop over into the rotating wheel and jam or chew things up, and, in the rear, you would get tunnel and/or flex-joint damage.

When we start putting in replacement parts, we become vehicle engineers. We have to consider all operating conditions andfailure modes. You can get this expertise through a balance of book-learning and practical experience. If you have some understanding of strength of materials, statics & dynamics and thermodynamics, and you have been doing hands-on vehicle building and repair for a few years, then go experiment! But remember, you have to validate your ideas with real testing, and that means getting some real wear and tear on the modifications.

John's quite right to point out that initial fit is just the first part of the game. And I would also caution that accepting advice about after-market vehicle modificationsshould be at your own risk.
<div align="left">Ed Price
<div align="left">El Cajon, CA USA
<div align="left">67 Rust Guppy
<div align="left">

rlgreen_55 · May 8, 2006

I totally agree with what John has stated regarding shocks. Whatever
people try all should be thoroughly tested under various conditions,
length of time, loads, etc. John's reference to the person going down
the road when a shock broke was in fact my wife and I. Had we been on
the expressway (of which would have been another few minutes) when
the rear shock broke it could have been fatal. It had been in use for
months and when it failed it chewed up Amphi quite a bit.

Shocks are highly tempered quality steel and cutting them creates
heat which softens the metal, now thread them and you take metal out
of the shaft thus reducing its size and load rating, then welding a
eye bracket below the threaded shaft does more damage to the temper
and its durability and rating. Just my opinion and experience.

The only way we can keep our Amphis running is by experimenting with
various substituted parts. Some things work and some don't but that
shouldn't stop us from trying. The main thing is be safe!

--- In amphicar-lovers@yahoogroups.com, "a_colo_native" <rma@...>
wrote:
>
>
> Gord
>
> Have you spoken with the manufaturer about what the specs are for
thse
> shocks? You can not just assume that because they will bolt in, that
> they will function properly and safely too. This is a very dangerous
> situation. These are designed for a 500LB snowmobile and not a
2660+LB
> car. The forces exerted on them are not even close to the same. An
> amphicar turning a corner at 20 MPH exerts lateral forces that no
> snowmobile could in any situation. The weight of the car alone is ~6
> times what they are designed for. With hi-way speeds and and a shock
> that is over taxed it will fail eventually (possibly a catastrophic
> failure). I would not place my car and passengers at that type of
risk.
> If you have spoke with the manufatures and they say it is safe,
then we
> should use them. It takes more than looking the part, it must
safely act
> the part as well. When other shocks have broken, had he had been
going
> down the road at even 35MPH (or 60MPH) when it broke, people could
have
> died or worse. The lives of your passengers depend on it. Please
let me
> know what they have said when you speak with them. Maybe they will
work
> just fine, we need to know for certain before something bad happens
> again. Maybe they will just wear our sooner but function safely.
This is
> just friendly concern for all of my fellow amphibians.
>
> John Bevins
>

Mike Israel · May 8, 2006

Re: Re: Kimplex shocks

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Shocks or anything structural. Make sure that any welding is professional grade. A MIG welder in inexperienced hands can literally be a dangerous thing. A typical 100V Harbor-Freight MIGwill not have the power to join many heavier pieces, despite what it says in the brochure. It is all to easy to simply lay a bead across the top of some metal which has not really fused the two pieced together. Even with a TIG, a sufficient amount of filler rod must be used to strengthen the joined pieces. With sheet metal, inexperience may lead to a warped panel or a leak. With structural pieces, inexperience may lead to dead. If you are welding something structural, that simply must not fail, at least have that piece done by a professional.

Kimplex shocks

a_colo_native

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WB6WSN

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rlgreen_55

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Mike Israel

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