Kimplex shocks - Welcome to The Amphicar Lovers Digest / Forum

**Kimplex shocks -** 05-06-2006, 11:36 AM

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

**RE: Kimplex shocks -** 05-06-2006, 06:51 PM

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

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.

Ed Price

El Cajon, CA USA

67 Rust Guppy