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WhirledTraveller
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Joined: January 09, 2008
Posts: 928
Location: Cambridge, MA
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 Posted: Mon Nov 29, 2010 11:35 am Post subject: |
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| SGKent wrote: |
| You don't want the sprung weight moving. You want just the suspension to rise and fall. You don't want the sprung weight accelerating up and down. The shocks are just to take energy out of the springs, not cause the springs to avoid absorbing the energy. |
This is just not the only issue. If the only issue was making the vehicle float down the road like a cadillac then yes you can make the springs do all the work of absorbing compression and just damp it out a bit on the rebound so the car doesn't bounce. However this introduces other issues and you'd need really stiff springs to avoid bottoming the suspension when you took a big hit like a pothole. The compression damping of the shocks takes that shock load off the springs in proportion to the velocity of the impact so you can have softer springs (nice for highway floating) and still not bottom out when the going gets rough. There are other issues as well. You can have a nice stable springy ride at the same time the wheels are bouncing up and down like mad and you might not even feel it. If they are bouncing they are losing contact with the road and you will lose traction. In order to properly control that bouncing you need to consider the inertia of the unsprung weight, the springiness of the tires, and probably a hundred other factors in addition to just the weight and motion of the vehicle itself.
You see fools all the time throw 20" heavy alloy rims and razor thin tires on their rides thinking it looks racey meanwhile they totally destroy the handling of the vehicle because the suspension isn't properly tuned for the new system. Point is shocks are not that complex themselves but they have a complex function and engineers spend a lot of time tuning for the best compromise. They don't just do "one thing".
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SGKent
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| Posted: Mon Nov 29, 2010 11:49 am Post subject: |
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| we can agree to disagree. |
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fusername
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Location: Boston MA
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| Posted: Mon Nov 29, 2010 3:40 pm Post subject: |
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| SGKent wrote: |
| we can agree to disagree. |
normally i am happy to see this get tossed into the middle of a technical debate, but this is one of the few that haven't immediately turned into a flame war and gone downhill from there. while it may be the final result, and this shock shopping thread is almost the wrong place to do it, why not continue while things are going well?
SGkent, I don't know if this is just a failure in my understanding of the physics here, but with conventional shocks, as long as there is compressive resistance (a function of velocity and nothing else, correct?) this can only be achieved by placing a force on the upper shock mount, and therefore moving the body. the only way to absorb the spring energy without moving the car up is by doing it all on rebound resistance, which apparently is not how its done, as someone mentioned many automotive shocks have zero or extremely light rebound damping, something i was unaware of. The only way a shock can dissipate energy is by trying to raise the sprung weight (chassis) on compression or to stop the unprung weight (suspension) from dropping, or stopping the bus from oscillating upwards after the wheel has been compressed.
can you explain how else the shock dissapates this energy without trying to make the body move? I think i am missing a step here.
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stever1000
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skid
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porschpow
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SGKent
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| Posted: Thu May 10, 2012 7:42 am Post subject: |
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call Eric and see what brand he has. We bought Nakata from him and were pleased. Sometimes he has Cofap or Boge. (They are all Brazilian). I highly recommend the Koni if you can afford them - or find a set of NOS Monroe HD or Gabriel HD from the 70's and you will have about the same.
http://bughaus.com/Type_2_front_shocks.htm
http://bughaus.com/Type_2_rear_shocks.htm |
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ddwbeagles
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Joined: May 12, 2009
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Location: Stephens City, VA
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| Posted: Thu May 10, 2012 7:50 am Post subject: |
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Old posting getting some activity. Toss in another recommendation for the german HD SACHS/Boge. Yes, the HD version, not the standards. Koni's get lots of love/raves, but if your looking for something better than KYB, yet more (available) and affordable than Koni's, you should consider. My side-to-side drift in high winds or when Truckers passed is gone and these alone have made for a more reassuring and comforting ride. Worthy of consideration.
....and "No", I have no affilations with the company or any vendor selling them.
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Wildthings
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| Posted: Thu May 10, 2012 9:54 am Post subject: |
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| ddwbeagles wrote: |
| Toss in another recommendation for the german HD SACHS/Boge |
Any help with finding a source? |
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porschpow
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| Posted: Thu May 10, 2012 11:53 am Post subject: |
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Yes I was divided between the boge's originals and the boge/sachs HD ones. I think I was quoted 42/F and 47/R pricewise. I wonder if they can get me the HD ones...Whats the difference. Stiffer ride?
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drober23
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| Posted: Thu May 10, 2012 12:07 pm Post subject: |
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Bus Depot has some Boge shocks that specifically state they are from Germany. They also have Koni at the moment.
They also list this one (Sachs/Boge High Performance Shock):
http://www.busdepot.com/details.jsp?partnumber=211413031PHD
I don't have experience with any of these, but my Konis are in the mail! 
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zerothehero
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| Posted: Fri May 11, 2012 2:06 pm Post subject: |
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I use the standard Sachs/Boge shocks and like the ride very much. I have also used the cheaper Cofap's in the past though and was OK with those.
Some people find them a bit soft but I like the comfort.
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SGKent
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| Posted: Fri May 11, 2012 3:38 pm Post subject: |
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| you just want a little heavier than standard in a bus. We replaced the Nakata with Koni and the handling improved a little. It was also a stiffer ride which reminded me of the 1971 deluxe I had - and all that was on it was a set of HD Monroes. Monroe today is not the same USA made Monroe of 1970. All those HD American made shocks are gone. Suspensions in cars have changed as well so the market is much different than it was in the 60 and 70's. The Nakata's were priced affordably compared to the Koni. I really think it would be interesting to compare a HD $20 shock from the 1970's to the Koni. IMHO the ride would be about the same. |
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ddwbeagles
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Joined: May 12, 2009
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Location: Stephens City, VA
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| Posted: Mon May 14, 2012 10:52 pm Post subject: |
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| Wildthings wrote: |
| ddwbeagles wrote: |
| Toss in another recommendation for the german HD SACHS/Boge |
Any help with finding a source? |
Bus Depot used to carry both versions and it's where I got mine. When it came in, they still have the OG Vendor's labels on them (Just Kampers) in the UK. Which is probably still a source. If not, VW Heritage also a UK vendors has them. With shipping, still cheaper than Konis.
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David W - from Chesterfield, VA / Jefferson SD / Stephens City, VA in that order.
71 Ghia Coupe autostick
78 Westy
86 Vanagon Weekender
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Wildthings
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| Posted: Tue May 15, 2012 4:21 am Post subject: |
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Thanks
| ddwbeagles wrote: |
| Wildthings wrote: |
| ddwbeagles wrote: |
| Toss in another recommendation for the german HD SACHS/Boge |
Any help with finding a source? |
Bus Depot used to carry both versions and it's where I got mine. When it came in, they still have the OG Vendor's labels on them (Just Kampers) in the UK. Which is probably still a source. If not, VW Heritage also a UK vendors has them. With shipping, still cheaper than Konis. |
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porschpow
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Posts: 1094
Location: Hamilton, NJ / Flanders, NJ
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| Posted: Tue May 15, 2012 3:29 pm Post subject: |
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There is a place called RPM foreign parts, they have the original German made Boge shocks, Ibelieve 42 for the front and 47 for the back
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