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 Post subject: Modern Clelands
PostPosted: Fri Jul 16, 2010 11:56 pm 
retrobike rider
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Modern and Future Clelands?

This is a forum in which to discuss the design of Geoff Apps' Cleland Cross Country Cycles. Both modern and old. It is also intended that anyone interested will be able to follow and contribute to the development of future Cleland designs.

What is a Cleland?
A Cleland is the bicycle equivalent of a trials motorbike. They are not however intended for 'Trials Riding' but for cross-country touring. The general idea is to design a reliable machine that can be ridden comfortably for extended periods of time. The 'Trials' bit is that you should not need to get off and walk if the going gets tough.

Clelands are not really mountain bikes at all, as they were developed independently of US style mountain bikes and so any similarities are coincidental. The fact that many of the features of the 1970/80's Clelands are to be found on modern mountain bikes is simply because Geoff Apps' design solutions were so ahead of their time.

What is it that distinguishes a Cleland from a mountain bike?
The long answer is, many subtle design details and engineering features.

However the most crucial are that like a trials motorbikes:

*Clelands use very low tyre pressures as a form of high frequency suspension. And a way of: reducing rolling resistance, increasing grip, and improving handling.

*Clelands are designed to be ridden in a style that motorbike trials riders call "on the pegs". This means that the rider stands bolt upright on the pedals, with no body weight on the handlebars at all. The bike is then allowed to articulate under the rider, as the rider's arms move in a rowing like motion as the handlebars rise and fall. This is a more efficient, alternative to low frequency suspension. No damping, no springs and the only mechanism is the bottom bracket axle . With practice the rider can even do this whilst pedaling hard. And by pushing and pulling the handle bars and utilising the pedaling reaction forces, the bike can be made to preempt, and not just react to the rise and fall of the trail.

In these two respects alone, riding a Cleland is a a very different experience to that of a mountain bike. And that's before we consider the differences in the braking and transmission systems etc.


Attachments:
Geoff and Cleland Dingbat1988.jpg
Geoff and Cleland Dingbat1988.jpg [ 64.95 KiB | Viewed 5239 times ]
File comment: This riding technique is classic Cleland. Rolling along whilst standing upright and letting the bike rotate, seesaw style, underneath you. From this position you can also hop either the front or rear wheel over any obstacles or in this case branches.
Cleland near Guildford June 1986.jpg
Cleland near Guildford June 1986.jpg [ 213.21 KiB | Viewed 5240 times ]


Last edited by GrahamJohnWallace on Sat Jul 24, 2010 8:35 pm, edited 1 time in total.
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 Post subject:
PostPosted: Tue Jul 20, 2010 7:12 pm 
retrobike rider
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This is a 700c wheeled Highpath' Big Blue.

This design can be made to order by David Wrath-Sharman at Highpath Engineering. This is at present is the only modern Cleland that uses a custom made frame.

David also has the parts to make the original 650b Highpaths apart from the 650b x2" (54-584) Nokia Hakkapeliitta tyres which have not been made since 1993.

The only other suitable low pressure tyre is the 650b x 2" (54-584) Nokian Hakkapeliitta STUD A10s. Nokian however. tell me that this size is no longer available despite still being shown on the Nokian website.

http://www.suomityres.fi/hkplstud.html

If anyone knows of a supply of these (54-584) tyres, please let me know.

In the mean time the search is on for some modern 650b tyres that can handle pressures as low as 15lbs PSI. The best bet may be to pair up some 650b tubeless tyres with some heavy duty downhill inner tubes.


Attachments:
Highpath BigBlue 1992 .jpg
Highpath BigBlue 1992 .jpg [ 221.23 KiB | Viewed 5218 times ]
1990s Highpath.jpg
1990s Highpath.jpg [ 34.41 KiB | Viewed 5218 times ]
H-u-b_B-r-e-a-k_S-n-a-p.gif
H-u-b_B-r-e-a-k_S-n-a-p.gif [ 106.48 KiB | Viewed 5218 times ]
Quarter_Big_Blue.gif
Quarter_Big_Blue.gif [ 33.22 KiB | Viewed 5218 times ]
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 Post subject:
PostPosted: Tue Jul 20, 2010 7:31 pm 
retrobike rider
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The Cleland frame geometry is similar to the geometries found on many modern bikes. So two styles of modern Cleland have been developed and built around modern stock frame-sets.

The top picture is a geometry shot of a 1988 Highpath Cleland hiding behind and Small framed 2005 Giant NRS3.

The middle picture is a geometry shot of a 1988 Highpath Cleland and a modern Cleland NRS prototype.

The bottom diagram shows the geometry of the 1988 Highpath Cleland shown in the pictures.


Attachments:
GeometryAa.jpg
GeometryAa.jpg [ 81.04 KiB | Viewed 5186 times ]
GeometryCc.jpg
GeometryCc.jpg [ 83.52 KiB | Viewed 5186 times ]
highpath_322.jpg
highpath_322.jpg [ 128.6 KiB | Viewed 5212 times ]
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 Post subject:
PostPosted: Tue Jul 20, 2010 11:30 pm 
retrobike rider
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Geoff Apps was in all probability designed and made the first 700c wheeled off-road 29er bicycle in 1981.

The top picture, taken in 1983, is Geoff and his 1981, 29er Cleland Aventura prototype.

The second picture is Geoff and his latest Cleland Aventura TT (2010)


Subsequent pictures show the TT and its features in more detail.

Geoff describes the TT as the bike he wanted to build 30 years ago, but could not find the high quality components that are available today.


Attachments:
File comment: Geoff Apps 1983
4707183738_085e45ac3b.jpg
4707183738_085e45ac3b.jpg [ 146.04 KiB | Viewed 5182 times ]
File comment: Geoff Apps 2010
4707181766_d4071f5a93.jpg
4707181766_d4071f5a93.jpg [ 117.82 KiB | Viewed 5182 times ]
File comment: Cleland Aventura TT
4686420376_ba8a573486_bb.jpg
4686420376_ba8a573486_bb.jpg [ 220.56 KiB | Viewed 5182 times ]
File comment: Geoff's swing pedal design
4463341368_a8fb97ff5d_bb.jpg
4463341368_a8fb97ff5d_bb.jpg [ 216.79 KiB | Viewed 5182 times ]


Last edited by GrahamJohnWallace on Wed Jul 21, 2010 10:27 pm, edited 1 time in total.
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 Post subject:
PostPosted: Tue Jul 20, 2010 11:54 pm 
North Wales Deputy AEC
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Fascinating - as ever...

Mr K


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 Post subject:
PostPosted: Wed Jul 21, 2010 1:50 pm 
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Do I spy Mavic ATB cranks on that proto?

If you're using 650B tubeless tyres I'm not sure why you wouldn't just run then tubeless, rather than stuffing a thick inner tube in there.


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 Post subject:
PostPosted: Wed Jul 21, 2010 1:55 pm 
King of the Skip Monkeys
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Would have to have a go on one.


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 Post subject:
PostPosted: Wed Jul 21, 2010 2:57 pm 
East Midlands AEC
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Yes I'd love to try one out - I like the idea of riding very upright. Any chance one might be brought to one of the national Retrobike meets? Peak? Turkey Twizzler?


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 Post subject:
PostPosted: Wed Jul 21, 2010 7:49 pm 
retrobike rider
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MikeD wrote:
Do I spy Mavic ATB cranks on that photo?

If you're using 650B tubeless tyres I'm not sure why you wouldn't just run then tubeless, rather than stuffing a thick inner tube in there.


Mavic ATB Cranks? the moment. The close up of the same crankset on a 2006 bike might help you to identify the make. The important factor is to have a small PCD in order to accommodate the minor axis of the elliptical granny wheel. For the Clelands NRS.
I use 58mm PCD chainsets sold under the Thorn brand.

Tubeless tyres and inner tubes?
The problem is that tubeless tyres are fine at 30lbs PSI but at 15lbs PSI they become unstable when cornering. The Idea of using heavy duty inner-tubes as well as tubeless tyres, is based on the fact that the original Cleland Hakka tyres used large, heavy duty tubes that weigh 8 oz each. Some heavy duty Kenda tubes have just arrived in the post, so I will soon know if this works. It is important to use tubeless rims as they don't let the tyres slip until the valves rip out.

But why carry around the extra weight of a heavy duty inner-tube?
On smooth surfaces it only makes sense in terms of increasing tyre contact patch and so the grip. On rough surfaces, like cobble stones, the low pressure tyres can absorb all the vibration and so reduce the rolling resistance. Tyre design is important in that an inflexible tyre will have a very high rolling resistance when run at low pressure. The original Cleland tyres are thick but flexible, and are remarkably quick off-road.


Attachments:
2006 Cleland Aventura II prototype.jpg
2006 Cleland Aventura II prototype.jpg [ 52.63 KiB | Viewed 5110 times ]


Last edited by GrahamJohnWallace on Wed Jul 21, 2010 9:43 pm, edited 1 time in total.
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 Post subject:
PostPosted: Wed Jul 21, 2010 9:30 pm 
retrobike rider
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orange71 wrote:
Yes I'd love to try one out - I like the idea of riding very upright. Any chance one might be brought to one of the national Retrobike meets? Peak? Turkey Twizzler?


The best place to try out a Cleland is at the Annual Cleland' Birthday-Ride, at Wendover Bucks, in early December. (Sometimes inaccurately called the Wendover Bash which was a Summer event).


I could take along a Cleland NRS to the OWMBC in September, though I don't think that this is the forum for modern bikes. Even those that are inspired by retro designs.

I would love to come along on a RetroBike ride as long as its not too far from where I live. The Peak meet in September may be do-able. Alternately, contact me if you are riding near the Chiltern hills or Berkshire downs.

Or if you are going near the NE Scottish Borders near Berwick upon Tweed , contact Geoff Apps and see If you can join in one of his rides.


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