Viewing 12 posts - 41 through 52 (of 52 total)
• Going for a ride with Geoff Apps and….
• Superficial
Free Member

Well, I’m not usually one for looking at a side-on photo of a bike and making assumptions about geometry, but anyone can see it’s fairly extreme. It’s not so much that I want to know what the geometry is, just how he thinks it improves the ride and in which situations it’s better. Does it require more/less rider input? If his main goal is riding technical stuff at slow speed, how does it help that?

mudrider
Free Member

OK,I think that I will split my answer into two.

First, some underlying physics.
It is counter-intuitive but tall objects fall over more slowly than short ones. This is why a pencil is more difficult to balance on an upturned hand than a broomstick. And the more top heavy an objects is the longer it takes to unbalance. This is a branch of physics called “Inverted Pendulum Theory”. A bicycle is a form of ‘inverted pendulum’ and so taller top heavy bicycles topple over more slowly than shorter ones with a lower Center of Gravity. http://en.wikipedia.org/wiki/Inverted_pendulum

The next bit of physics is related to the fact that on Cleland bikes, most of the weight is over the rear wheel but is balanced by the side to side movements of the front wheel. Basically, on a bicycle with the rider weight over the front wheel you only need small adjustments of the steering to balance the bike. With the weight at the back you need far bigger movements. i.e.front wheel side to side motion is less likely to unbalance the bike.

Combine these two factors and you have a bike that falls over more slowly and front wheel that can wonder about without upsetting the balance of the bike.

Another benefit of having most of the weight on the back wheel is improved rear wheel traction and a front wheel that rolls over obstacles more easily.

Secondly because I’m feeling lazy, I will cut & paste an owners description of Riding a 1983 Cleland, that was recently posted on RetroBike.

“I find when seated that the upright position is fantastic for being able to look around you. It is much more ‘sightsee-ey’ than the more normal stretched out mtb position. But that short wheelbase and upright position make it very easy to lift or unweight the front wheel. Handy on rough terrain. But the setup makes the most sense when stood on the pedals. You stand almost bolt upright in a very relaxed and natural position. The similaritys to a trials motorcycle riding position are deliberate. It is difficult to explain how this allows the bike to move around underneath you, but it feels very natural. Geoff also believes that this is a good position for spinal health.”

Cheezpleez
Full Member

If I had the wherewithal to put a frame together, I’d love to build one of these.

I’ve got five MTBs and I thought they were all different. Now I feel like they’re all the same.

epicyclo
Full Member

Cheezpleez – Member
If I had the wherewithal to put a frame together, I’d love to build one of these.

You get a close approximation of that geometry by modifying an old suspension bike frame.

Just replace the suspension unit with a solid rod of an appropriate length, and you can dial in your head angle.

The fork then becomes the next hurdle, but again by modifying an old suspension fork into a rigid and locking in the right position you can get close. You can reverse the crown to fiddle with the offset.

AlexSimon
Full Member

The article on Geoff in Privateer was the highlight of the whole publication imo.
Really fascinating.

I thought the whole point of the pedals was to allow a high BB while retaining low CoG, didn’t know there were other benefits – interesting.

Deveron53
Free Member

It feels like that is like one of these:

whilst modern enduro mountain bikes are more like one of these:

Au contraire! The Lancia was how mid-90s bikes rode. Modern trail bikes are like this:

mudrider
Free Member

epicyclo – Member

Cheezpleez – Member
If I had the wherewithal to put a frame together, I’d love to build one of these.

You get a close approximation of that geometry by modifying an old suspension bike frame.

Just replace the suspension unit with a solid rod of an appropriate length, and you can dial in your head angle.

The fork then becomes the next hurdle, but again by modifying an old suspension fork into a rigid and locking in the right position you can get close. You can reverse the crown to fiddle with the offset.[/quote]
About eight years ago I noticed that a small Giant NRS frame had the same frame fundamental geometry as a Cleland. If the suspension is run ‘topped out’, this even includes the higher than normal bottom bracket height as running ‘zero sag’ was recommended with the NRS.

So I bought an NRS, fitted a longer seat-pin and a long tall stem and a variety of other bits that Geoff was using at the time. Since then I have also built two others.

The only problem with this is that you have to use 26″ wheels and in winter time, fit 1.9″ wide tyres, because the mud clearances on the NRS or other mountain bikes are nowhere as good as those on the best Clelands.

I know of quite a few riders who have built their own Cleland style bikes. Probably because, despite the design being around for over 30 years, they can’t go out and buy anything remotely like them.

ajantom
Full Member

…and back to the thread I started. Not been logged on for a few days, and it’s good to see a discussion going on!

I’m hoping to braze up a Cleland style frame over the winter, just need to source an appropriate tube set, and work out if I’m going to bother making a jig, or just bodging it 😉 I also need to find a cheap donor bike with either Nexus or Alfine gears on it.

mudrider
Free Member

I found this on eBay:

http://www.ebay.co.uk/itm/carrera-subway8-20-in-frame-alloy-8-speed-needs-work-nice-project-/231374733556?pt=UK_Bikes_GL&hash=item35df0240f4

Sometimes people who specify ‘collection only’ may be happy to pop the bike into an old unwanted bike box from their LBS, and for the buyer arrange a courier to collect from them.

Also, Giant and Ridgeback made similar Shimano/Nexus inter8/Roller-Brake bikes a few years back.

marka.
Free Member

I love the project. It’s the sort of thing that Pashley should try to make (to keep it British), but in reality it’s sort of a Jones already. Make it out of titanium, change to fancier forks and sell it for \$\$\$.

Geoff Apps’ reasons for choosing big wheels, very low tyre pressures and motorbike inner tubes seem to be the same reasons why people now like fat bikes. So I wonder if Geoff will rethink and rebuild the Landseer to take the massive tyres.

jamj1974
Full Member

Nice work mudrider!

mudrider
Free Member

mark a. – Member
Geoff Apps’ reasons for choosing big wheels, very low tyre pressures and motorbike inner tubes seem to be the same reasons why people now like fat bikes. So I wonder if Geoff will rethink and rebuild the Landseer to take the massive tyres.

Indeed, the fat-bike riders seem to share a very similar riding ethos to that of Geoff Apps.

However,the last time I rode with Geoff in July, he said that he thought that fat-bike tyres where too bouncy and did not have the handling characteristics he was looking for. I would say that his current thinking is more 29er+ based but using narrow rims. So maybe 700c or 650b rims with 3″ tyres.

Two years ago I looked into the feasibility of building a fat-bike framed Cleland on which the wheels/tyres could easily be swapped over depending on the riding conditions. I still like the idea, but have no plans at present to build one. Though this could change if I found an off the shelf fat-bike frame with the correct geometry.

Though I like the idea of extra flotation, one issue I have with fat-bike tyres is their high rolling resistance in sloppy mud and potential for building up heavy mud deposits when riding in sticky conditions.

Having larger diameter,narrower tyres is probably the best “one size fits all” solution for a Cleland style bike. Though one frame and a variety of inter-changable wheel sizes sounds ideal, though expensive. Especially for the Rohloff geared bike I am currently working on.

Viewing 12 posts - 41 through 52 (of 52 total)

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