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#391
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"Actually you are the first person to bring up this issue"
"Russ" wrote in message ... The issue of retrospectively recalling all existing forks is much more problematical and possibly unecessary, that's something that will be addressed by the manufacturrs in the light of legal cases and costs. I'd have thought that "lawyer-lips" have set a precedent that gives manufacturers a loop-hole to use regarding forks already on the market/in use. Lawyer lips were created not because of any inherent design flaw but because there was a risk of user error, ie the user *might* forget to tighten the QR correctly before riding or might not do it correctly. So there is no admission of an engineering problem, just an acknowledgement that someone may not use the device as intended and therefore a belt-and-braces (belt-and-suspenders for our American friends) approach has been adopted.. So based on this there is no reason why manufacturers couldn't move the mounts to the other leg, they wouldn't be admitting to any previous liability due to poor design but would be seen to be further addressing the risk of user error. -- Regards, Pete |
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#392
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"Actually you are the first person to bring up this issue"
Tom Sherman writes:
I didn't see a picture of this tricycle but short wheelbase recumbent bicycles, ones where pedal cranks are ahead of the front wheel, do endo's more easily than a conventional bicycle. Drawing a visual line from the rider's belly button (rider CG) to the contact patch of the front wheel shows that the CG is no better positioned than that of a conventional bicycle and usually worse.... Picture of my trike. http://www.ihpva.org/incoming/2002/df1a.jpg This picture could not be retrieved. The URL produces an error. Mr. Brandt's comments on short wheelbase (SWB) recumbents indicate outdated and/or incomplete knowledge. The first regular production SWB recumbent was the Hypercycle. Among other design defects, the Hypercycle had a very long pedal boom, which meant that the rear wheel would lift easily when the front brake was applied, and hard braking could well launch the rider off the front of the bike in a near standing position and/or put the chainring into the ground. Better designed (not all, by any means) modern SWB recumbents have a static weight distribution of approximately 40%/60% front/rear and will not lift the rear wheel under hard braking. Here is one such common design that I have ridden extensively (including emergency braking) without ever lifting the rear wheel. http://www.ransbikes.com/2004Bikes/Rocket.htm This is the exact design to which I refer. Drawing a line from the tire contact patch to the belly button of the rider produces a steeper inclination than a conventional bicycle. An endo was demonstrated by a rider who was convinced it would not occur. He left the recumbent behind as he went over the pedals to run down the parking lot. It was a relatively benign dismount although the bicycle got a few scrapes. Don't try this at higher speeds. Here is a picture of the SWB recumbent I regularly use for longer rides: http://www.ihpva.org/incoming/2002/sunset/Sunset001.jpg With the low seat height and short pedal boom, the angle formed by the ground, front tire contact patch, and combined bike/rider center of mass is very small. It would take sudden stoppage of the front wheel (e.g., wedged in a storm sewer inlet grating) for the rear wheel to lift off of the ground. That is certainly a compendium of mechanical oddities, unistrut fork, front spoke guard, primary and secondary chains with cross-over and dual tensioners. The tiller style steering is also unusual for using arm force while pedaling. How do you keep pant legs out of the chain? In the line with this thread, I cannot see riding this on steep trails or trails at all for that matter. Jobst Brandt |
#393
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"Actually you are the first person to bring up this issue"
James Annan writes:
If you consider forks without offset at the dropout end, as they are commonly made today, where offset is achieved at the fork crown, No change other than placing the mounting lugs for the disc brake caliper on the front side is required. I think the same caliper would be adequate for most brands with the distance between caliper and fork leg remaining as it is today. This requires a new fork strut anyway. It might even be possible to simply swap the left and right fork lowers. Sometimes one sees bikes where the forks have been installed backwards... usually on ebay. How long will it take to get the disc caliper ahead of the fork leg? I wouldn't be surprised to see different wheel attachment instead. There are already various quick(ish) release 20mm systems that seem little more trouble than a QR with retention lips. That can also be sold as an upgrade rather than merely a bug-fix. And you get to buy a new shiny hub too! Well that won't do as I already mentioned. The reversing load from braking and bouncing on the road makes anything but a conical "lug nut" ineffective to reliably prevent loosening. Let's get the caliper in the right place! Jobst Brandt |
#394
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"Actually you are the first person to bring up this issue"
On Mon, 29 Mar 2004 12:38:21 +0100, "Just zis Guy, you know?"
wrote: "Chris Malcolm" wrote in message ... bomba writes: Since most bike brakes are capable of skidding the front wheel in most circs, all that better brakes give you is finer control of braking force and less grip effort. And less fade. Why? |
#395
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"Actually you are the first person to bring up this issue"
Chris B. wrote:
"Just zis Guy, you know?" wrote: "Chris Malcolm" wrote: Since most bike brakes are capable of skidding the front wheel in most circs, all that better brakes give you is finer control of braking force and less grip effort. And less fade. Why? Brake fade is bad. If brakes give you less of it, it follows that they are better, all else being equal. I assume Chris Malcolm wasn't including dry pavement when he said "most bike brakes are capable of skidding the front wheel in most circs". On dry pavement the limiting factor is nearly always geometry rather than traction or "brake power". -- Benjamin Lewis F u cn rd ths u cnt spl wrth a dm! |
#396
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"Actually you are the first person to bring up this issue"
On Mon, 29 Mar 2004 12:53:42 -0800, Benjamin Lewis
wrote: Chris B. wrote: "Just zis Guy, you know?" wrote: "Chris Malcolm" wrote: Since most bike brakes are capable of skidding the front wheel in most circs, all that better brakes give you is finer control of braking force and less grip effort. And less fade. Why? Brake fade is bad. If brakes give you less of it, it follows that they are better, all else being equal. I agree but the implication was that disc brakes are more fade resistant (all of the other points Guy mentioned were positive traits of disc brakes), although this isn't clear by looking at the quoted section. No doubt Guy will clarify if he was instead referring to rim brakes. Again, I often hear that disc brakes are less prone to fade resistant and I wonder if it is true and why. |
#397
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"Actually you are the first person to bring up this issue"
On Mon, 29 Mar 2004 21:17:54 GMT, Chris B.
wrote: snip Sorry, that should read "I often hear that disc brakes are less prone to fade and I wonder if it is true and why." |
#398
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"Actually you are the first person to bring up this issue"
Chris B. wrote:
On Mon, 29 Mar 2004 12:53:42 -0800, Benjamin Lewis wrote: Chris B. wrote: "Just zis Guy, you know?" wrote: "Chris Malcolm" wrote: Since most bike brakes are capable of skidding the front wheel in most circs, all that better brakes give you is finer control of braking force and less grip effort. And less fade. Why? Brake fade is bad. If brakes give you less of it, it follows that they are better, all else being equal. I agree but the implication was that disc brakes are more fade resistant (all of the other points Guy mentioned were positive traits of disc brakes), although this isn't clear by looking at the quoted section. No doubt Guy will clarify if he was instead referring to rim brakes. Again, I often hear that disc brakes are less prone to fade resistant and I wonder if it is true and why. I see -- your question was a little unspecific. It would surprise me to find that disc brakes were less prone to fade, since they appear to have much less surface area available for heat dissipation, but there may be other factors I'm overlooking. They certainly must reduce the chances of tire blow-off due to heating of rims, but this is a different question. -- Benjamin Lewis F u cn rd ths u cnt spl wrth a dm! |
#399
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"Actually you are the first person to bring up this issue"
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#400
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"Actually you are the first person to bring up this issue"
"Doug Taylor" writes:
"Tim McNamara" wrote in message ... Not much of a clue, that, since the thread is also cross-posted to rec.bicycles.tech which has an international audience as a matter of course (although seems largely American) and alt.mountain-bike which has an audience of who-knows-what. People who know and ride the bikes that are being discussed. Unlike you. Well, now, that was certainly a charming response. It's unclear on what grounds you think this to be the case, nor why you felt the need for spurious invective. Ah, well, like many mysteries it will no doubt remain unexplained. |
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