Long travel?

Mr. G
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2/1/2010 10:45am Edited Date/Time 1/27/2012 10:48am
Here is a question for the suspension guru's. OK it might be a stupid question but what the heck. Anyway you know how the off road vehicals (4 wheel) run very long suspension with tons of sag? Why have dirt bikes never gone down that path. I remember back in the early 80's there was a suspension battle going on and since then the amount of travel has shortened a bit ( I think ) and has of course settled into a quality over quantity. Would dirt bikes just be too unridable with the car setup? Just a thought.
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BK
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2/1/2010 11:44am
Ozy
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2/1/2010 11:47am
too much time to rebound if they had 14" of travel with 7" of sag.

that's my guess
newmann
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2/1/2010 12:00pm
Late 70's saw a lot of bikes and aftermarket forks running a fairly long and soft negative pressure spring allowing the suspension a few inches of "float" instead of topping out on a 3/4 inch long rebound spring or no rebound spring at all. Those were the days of standard dampening rods and no external compression or rebound adjustments. Not too good. I still think this setup with the proper internals has the potential to offer the best fork action ever. Jeff Wilson's (San Antonio, Tx.) version of something Showa never followed through with. Seems to me you could literally have one stage rebounding and the other stage soaking up the next bump.





Mr. G
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2/1/2010 12:53pm
Is that why the bikes of late 70's early 80's looked like they had more travel than of today?

The Shop

mcopsey
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2/1/2010 1:05pm
newmann wrote:
Late 70's saw a lot of bikes and aftermarket forks running a fairly long and soft negative pressure spring allowing the suspension a few inches of...
Late 70's saw a lot of bikes and aftermarket forks running a fairly long and soft negative pressure spring allowing the suspension a few inches of "float" instead of topping out on a 3/4 inch long rebound spring or no rebound spring at all. Those were the days of standard dampening rods and no external compression or rebound adjustments. Not too good. I still think this setup with the proper internals has the potential to offer the best fork action ever. Jeff Wilson's (San Antonio, Tx.) version of something Showa never followed through with. Seems to me you could literally have one stage rebounding and the other stage soaking up the next bump.





Man, I would love to tear those things down and have a peek inside.
Rooster
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2/1/2010 1:58pm
There was a system that Danny LaPorte brought back from Europe that was used quite a bit in F1. It basically had no sag and sat very low in the travel. MXA tested it and found it something stupid like 4.5 seconds a lap faster on average.

They described it as feeling like you were running over a log if you hit a garden hose in the pits, but at speed it became totally plush. The forks required an external rod, but there were supposed to be working on a system that made them completely internal.

I asked Rob Hendrikson @ RG3 about them at the time, and if anybody was actually using them in competition. He hinted that there was one guy, but wouldn't say much about them or who it was. This was back in McGrath's dominant era. I'm not sure but I think FMF was looking at buying the rights to use the technology for MX.

Then for some reason the technology just seemed to die off and was never spoken of again.

I'd love to know more about the system and particularly why it disappeared. If MXA's test was any indication, it was definitely a game changer.
ocscottie
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2/1/2010 2:15pm Edited Date/Time 4/17/2016 8:31pm
I know this is way random and OT, but check the suspension on this thing out:

Crazy 4x4 suspension
lumpy790
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2/1/2010 2:30pm
Wasn't the rod thing from Race Tech and for data acquisition?
Rooster
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2/1/2010 3:00pm
lumpy790 wrote:
Wasn't the rod thing from Race Tech and for data acquisition?
No I don't believe it was any sort of data acquisition system. There was no mention of any electronics involved in their operation.
Ing
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2/1/2010 3:19pm
I think the basic problem with longer suspension travel (over 12") was that it changed the steering angle too much from full compression to full extension.
Pdub
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2/1/2010 3:33pm
Ing wrote:
I think the basic problem with longer suspension travel (over 12") was that it changed the steering angle too much from full compression to full extension.
There's that, and there's the matter of raising the center of gravity too high and compromising the handling.
Moto Mofo
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2/1/2010 4:58pm
Rooster wrote:
There was a system that Danny LaPorte brought back from Europe that was used quite a bit in F1. It basically had no sag and sat...
There was a system that Danny LaPorte brought back from Europe that was used quite a bit in F1. It basically had no sag and sat very low in the travel. MXA tested it and found it something stupid like 4.5 seconds a lap faster on average.

They described it as feeling like you were running over a log if you hit a garden hose in the pits, but at speed it became totally plush. The forks required an external rod, but there were supposed to be working on a system that made them completely internal.

I asked Rob Hendrikson @ RG3 about them at the time, and if anybody was actually using them in competition. He hinted that there was one guy, but wouldn't say much about them or who it was. This was back in McGrath's dominant era. I'm not sure but I think FMF was looking at buying the rights to use the technology for MX.

Then for some reason the technology just seemed to die off and was never spoken of again.

I'd love to know more about the system and particularly why it disappeared. If MXA's test was any indication, it was definitely a game changer.
the name of this setup was "contractive suspension".
2/1/2010 5:55pm
It may seem odd but some riders actually run less travel, esp. in SX. It is far better to have less really good travel than more not so good. You can get to a point where too much travel has the ability to upset the handling, and changes the attitude of the bike too much in a given situation. There is also another reason why you do not see the setup above (the RC replica bike) and that is because of the amount of flex that is a by product. For a MX bike the front doesn't have nearly as much side to side flex as it does fore and aft. A purely inverted fork handles fore and aft much better than conventional. The damping systems in current MX suspension has the ability to work in different areas of stroke, shaft speeds, and a mixture of the two. But to answer the question, 10-12" of really great controled travel is far better than 12-14" of flexy good travel.

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