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PostPosted: Tue Jul 09, 2013 9:10 pm 
retrobike rider
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Joe of Loath wrote:
Hmm interesting, thanks! Will keep an eye out at the local bike co-op for retro hybrids in massive sizes, as the other options seem prohibitively expensive.


eBay may also be worth watching?

Below is the Rolls Royce of 700c British off-road bicycles. A Highpath Big Blue circa 1992.


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PostPosted: Tue Jul 09, 2013 9:15 pm 
Old School Hero

Joined: Mon Apr 22, 2013 1:56 am
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Not really keen on the styling, however cool it may be I'm afraid.


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PostPosted: Tue Jul 09, 2013 9:18 pm 
retrobike rider / Gold Trader
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Location: Wherever it is, I'm being just that little bit more Lance
GrahamJohnWallace wrote:

The problem here is most 29er's outside tyre diameter is actually less than 29 inches.
Take the tyre credited with starting the modern 29er movement, the WTB 700x52c Nanoraptor.
A 622mm diameter rim plus two 52mm tyre sections gives an outside diameter of 726mm or 28.5826771653852 inches. Or 28.58 when rounded down.

So "the first real 29er tyre did not measure 29 inches it was just closer to 29" than to 28".




Or 28.6 inches when rounded a bit further

Or 29 inches when rounded further still.

So the first real 29er tyre measured 29 inches to the nearest whole number.


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PostPosted: Tue Jul 09, 2013 10:52 pm 
Retro Guru
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Joined: Thu May 03, 2012 7:13 pm
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Location: The Cock Inn, Tillett, Herts
GrahamJohnWallace wrote:
Joe of Loath wrote:
Hmm interesting, thanks! Will keep an eye out at the local bike co-op for retro hybrids in massive sizes, as the other options seem prohibitively expensive.


eBay may also be worth watching?

Below is the Rolls Royce of 700c British off-road bicycles. A Highpath Big Blue circa 1992.

You could've warned me - I saw that pic and my Y Fronts exploded leaving my blue veiner in full view and me having to apologise to the Vocal and the chairman of the Rotary.


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PostPosted: Thu Jul 11, 2013 9:49 am 
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That Big Blue is completely awesome :)


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PostPosted: Thu Jul 11, 2013 5:42 pm 
retrobike rider
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MikeD wrote:
That Big Blue is completely awesome :)

Some of the advanced technologies on that 1992 bike are only just appearing in the shops today:
*100mm wide bottom bracket shell
*Elliptical chainset with the correct and optimum offset of the cranks relative to the major axis of the ellipse
*700c rims and fat tyres


Features that are not currently available in the shops but should be:
*Drop-swing pedals
*Lightweight 90mm diameter hub brakes with self centering brake shoes

Other interesting features:
*Fully triangulated frame design with asymmetric rear triangle
*Made to measure so seatpost and saddle structures that are part of the frame
*Built in lighting system


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PostPosted: Thu Jul 11, 2013 7:07 pm 
BoTM Winner
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Joined: Sat Mar 21, 2009 6:19 pm
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Location: USA
Please tell me how hub brakes are superior to current disc brakes. I have three bikes with hub brakes (41 DX Klunker, 37 C Klunker, and a 79 Champion Cruiser). The hubs range from the 50's (Atom), 70's (SA SB), and 2010's (SA). Two sets of them are era correct, one just is playing the part.

Pretty yes:

Image



Image


None of them come close to the modern hydraulic disc brakes on my Turner (Avid) or my WTB (Avid).

Image

Image

Low maintenance, ease to change a tire, superior stopping power absolutely.

Something to dwell over next time you are changing out a tube.


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PostPosted: Thu Jul 11, 2013 8:35 pm 
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Joined: Mon Apr 22, 2013 1:56 am
Posts: 164
I used to race electric cars. Small things, basically 4 wheel recumbants with a 250w motor instead of pedals. Two Sturmey hub brakes on the front could stop 180kg of driver, batteries and car from 30mph in about 10 metres. Never had disc brakes on any of our cars, but I can't think of much that would stop faster.

Plus over thousands of miles of racing we never had to change a shoe or a drum.


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PostPosted: Thu Jul 11, 2013 8:50 pm 
retrobike rider
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Hi Ductape,
All the hub brakes you have on your bikes have the same fundamental problem. The leading and trailing brake shoes wear at different rates until only the least effective trailing shoe is doing all the work. There are three solutions that I know to this issue.

1/ use hydraulic activation as this automatically divides the pressure equally between the shoes, regardless of the different rates of wear.

2/Use floating input cams like those used on Cleland and Highpath bikes. Here the activating cam can move side to side between the brake shoes and so self-centres to compensate for any difference in brake shoe wear.

3/Use multiple cams like the Shimano Roller-Brakes


Why are the best hub brakes better than modern disks?

1/The modulation characteristics are better because their is a longer distance between where the brake lever starts to bite and the point where the wheel locks.
2/The workings are enclosed as are the wheel bearings so there is less maintenance and brake shoe wear. (Despite frequent all weather use the rear brake shoes on my Highpath have never been changed and I bought that bike in 1988)


Why are modern disks better than the best hub brakes ?

1/They are lighter. But over the past thirty years, very little research and investment has gone into reducing the weight of hub brakes)
2/They make it easier to remove the wheels than hub brake designs do.


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PostPosted: Fri Jul 12, 2013 12:28 am 
BoTM Winner
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Location: USA
Then I am suprised downhill bikes where weight isn't as big an issue but tenths of a second are, haven't adopted the system.
I would guess the brake pad wear is about the same. One is just over a much larger surface area (never researched drum brakes beyond what was proper for my projects and how they worked). Why haul around 25 years of brake pad when you can just add new once a year or so.

Make my modern bikes disc.

For the most part quality Cars, motorcycles, and bicycles have left the drum brake behind. Profit margin?


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