Author Topic: 1960's Vs 2002  (Read 6526 times)

Re: 1960's Vs 2002
« Reply #25 on: April 04, 2008, 12:47:06 pm »
I reckon it's mainly the oversized tubes and the Armadillo tyres that make the difference. Those tyres are very hard and rigid, they probably ride like as if they were solid plastic.

border-rider

Re: 1960's Vs 2002
« Reply #26 on: April 04, 2008, 12:49:38 pm »
I'd tend to agree

My>Clarion's>Nutty's  frankenfixie has massive tubes, and had the aforementioned "solid" Armadillos inna 40 mm size.  It was incredibly rigid, even with a laid-back geometry and comedy clearances (40 mm tyres, guards and then still enough room for a small bus)

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Re: 1960's Vs 2002
« Reply #27 on: April 04, 2008, 12:53:41 pm »
It is possible to get a less flexible tyre to feel as comfortable as a more flexible one simply by inflating it less (although rolling resistance would be higher then).
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Re: 1960's Vs 2002
« Reply #28 on: April 04, 2008, 12:55:55 pm »
It has a similar effect, but probably wouldn't quite rescue the tyre with sidewalls of teak (to use MV's expression).  Ideally you can use a pretty high pressure and still get a decent ride.
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Re: 1960's Vs 2002
« Reply #29 on: April 04, 2008, 12:59:51 pm »
The problem with under inflating a thick and rigid tyre are snakebite puntures and getting dents or flats spots on your rims. But I suppose this would be less of a problem with wider tyres.

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Re: 1960's Vs 2002
« Reply #30 on: April 04, 2008, 02:02:26 pm »
The problem with under inflating a thick and rigid tyre are snakebite puntures and getting dents or flats spots on your rims. But I suppose this would be less of a problem with wider tyres.

Agreed, except they don't have to be all that wide to avoid the problem.

I reckon with 28mm ones (maybe even 25mm), it is possible to have nasty rigid tyres soft enough to be comfortable, yet hard enough to avoid snakebites and rim damage for all but the most outrageous potholes.

The only disadvantages then would be increased rolling resistance and wear rate, plus the extra weight of the tyres compared to more flexible ones which tend to be lighter.
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Really Ancien

Re: 1960's Vs 2002
« Reply #31 on: April 04, 2008, 03:02:06 pm »
I've just come back from a ride on the hastily ressurected 82 Record Ace and it rides better than my Hewitt Cheviot with carbon forks. I got to thinking about the bikes of the 60s and that 1963 is as close to the end of the First World War as to today and that the older guys building the bikes had probably started riding on unsealed roads.

Damon.

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Re: 1960's Vs 2002
« Reply #32 on: April 04, 2008, 03:15:57 pm »
I've just come back from a ride on the hastily ressurected 82 Record Ace and it rides better than my Hewitt Cheviot with carbon forks. I got to thinking about the bikes of the 60s and that 1963 is as close to the end of the First World War as to today and that the older guys building the bikes had probably started riding on unsealed roads.

Damon.

Just like the Fen Roads round here then !!

Really Ancien

Re: 1960's Vs 2002
« Reply #33 on: April 04, 2008, 03:31:38 pm »

Just like the Fen Roads round here then !!

We call them Meanygates in Lancashire, raised roads out across the Mosses.

Damon.

Re: 1960's Vs 2002
« Reply #34 on: April 04, 2008, 04:38:33 pm »
I'd go for the fatter tubes explanation. Since september I have a new Bob Jackson with a fairly relaxed geometry, slighly ovesized Reynolds 631. If I compare it's behaviour on cobbles with that of my '97 era Bioracer with non-oversized Columbus Brain (except for the toptube) the Bioracer is much more comfortable on cobbles despite the more race geometry.

Re: 1960's Vs 2002
« Reply #35 on: April 04, 2008, 05:41:29 pm »
Dawes..    700*25 Spesh Armadillos      110 PSI
Carlton     700*23  Vittoria Pro tetch     125 PSI

Wow--given that you're comparing rides on rough roads, I was surprised to see such skinny/firm tires. But since I've been riding 700x32 at 65/70 psi, we may just have very different preferences.

There's a very narrow window of acceptable fork offsets for a given head angle; so I suspect your Mercian has a slacker-than-normal head angle (racing bikes are normally 73 or 74 degrees head, with an offset of 43-45mm).

If you get too much offset the bars get floppy

Ewww, cycling debate!  ;)  Saddlebags at 10 paces?

Jan Heine at Bicycle Quarterly has done a lot of research into this, and concludes (in my incompetent summary) that longer fork offsets and normal-ish head angles make for more stable bikes, especially at low-medium speeds. His tests seem to be pretty convincing, if counter to common assumptions.

OK, I'll crawl back into my little poseur burrow now and leave this to the real cyclists....  :-[ :-\
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Re: 1960's Vs 2002
« Reply #36 on: April 04, 2008, 06:32:02 pm »
Counter-intuatively perhaps, when the head angle is the same, a greater fork offset makes the steering quicker, not more stable.

See www.phred.org/~josh/bike/trail.html
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Re: 1960's Vs 2002
« Reply #37 on: April 04, 2008, 06:36:27 pm »
If I understand correctly, that is essentially the opposite of what Jan Heine's research has found. I hate to summarize what he's found, though--this is the kind of thing that sets of long debates elsewhere, and I don't want to misquote him.
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Re: 1960's Vs 2002
« Reply #38 on: April 04, 2008, 06:50:25 pm »
The webpage I mention was linked to by Sheldon Brown, and has been cited by others on the rec.bicycles.tech newsgroup many times over many years - so I think it's probably correct.  However I'm not sure from personal experience because I'm never sure that everything else is the same when the fork offset has been different.  A difference in head tube angle, and other things, can more than make up for a difference in fork offset.
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Re: 1960's Vs 2002
« Reply #39 on: April 04, 2008, 06:55:54 pm »
If you look at almost any bike, you find that the ones with the shallow head angles have the greatest offset.  Otherwise the trail - a measurable dimension, but essentially what gives the bike its self-centreing tendency - would be huge, making the steering "stiff" and unresponsive.
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Rollo

Re: 1960's Vs 2002
« Reply #40 on: April 04, 2008, 08:39:54 pm »
Veering a bit off-topic, this is an old but great article by a physicist looking at bicycle stability and factors influencing it, amongst them fork rake and +ve/-ve trail.  Nothing about comfort though, I'm afraid.

Re: 1960's Vs 2002
« Reply #41 on: April 04, 2008, 08:59:43 pm »
The webpage I mention was linked to by Sheldon Brown, and has been cited by others on the rec.bicycles.tech newsgroup many times over many years - so I think it's probably correct.  However I'm not sure from personal experience because I'm never sure that everything else is the same when the fork offset has been different.  A difference in head tube angle, and other things, can more than make up for a difference in fork offset.

It's all very complex, and far over my head. But I think the point of a lot of Jan Heine's research is that a lot of the longstanding assumptions about what makes for "stability" hold true at high (racing) speeds, but not at more typical riding speeds. And there's the whole language and perception problem about what various riders prefer and call "stability" or "ability to pick a line" or.....
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Re: 1960's Vs 2002
« Reply #42 on: April 04, 2008, 09:47:03 pm »
It's all very complex, and far over my head. But I think the point of a lot of Jan Heine's research is that a lot of the longstanding assumptions about what makes for "stability" hold true at high (racing) speeds, but not at more typical riding speeds.

I'm not sure about that.

Quote
And there's the whole language and perception problem about what various riders prefer and call "stability" or "ability to pick a line" or.....

This I definitely agree with, and makes it a tricky subject.  People can mean different things even by terms as basic as "quick steering".
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