DIY recumbent bike....?
Posted: 1 Jun 2015, 1:08pm
Well.... where to begin....?
I think it is fair to say that I am a life-long rider of 'normal' bicycles. Out of curiosity, I have tried recumbents in the past, and of course if you wish to go as quickly as possible, a low-slung recumbent position appears to be almost obligatory. But until recently the idea of owning such a machine did not appeal to me; they were for the most part expensive oddball machines, lacking in basic practicality.
Of particular concern is the perceived (certainly, if not actual, always) problem that a low slung machine may be missed by other road users. Having ridden a motorcycle for many years, I know all about that... and I know that the average motorist is looking out for other cars first, (lorries and buses too) slow-moving normal bicycles (if you are lucky) and then a third 'other' category. Rightly or wrongly, there is a perception that 'not being seen' may truly be a matter of oversight if you are riding a low-slung machine.
In the long term I have all kinds of mad ideas about much faster machines, but in the shorter term I realised that I would need a machine that I could use (much as I use an normal bike) with a recumbent position, just to train on and try a few ideas out. I looked at those you can buy and they seemed expensive (for what they are), mostly with a riding position that is lower than I'd like, and not particularly amenable to being messed about with.
So I decided to build my own '(very) high racer recumbent' machine.... starting with a motley assortment of knackered mountain bikes, and a few other odds and ends, I have built this;
Now the saddle is a lash-up... but this machine has 700C wheels and the seat height is much like that of a normal bike. When stopped, you can straddle the machine but only if the lowest part of the saddle is narrow enough to go between your legs. ( I still don't know if I will ever come to a happy compromise in this respect; all constructive suggestions welcome).
At first, I couldn't ride the thing at all, and I was seriously worried that I'd built something unrideable. But since then I've stuck with it and I've (over a period of about a week and forty-odd miles) become vaguely competent with it.
In terms of the design objectives, although it is early days yet, it appears to have worked, in that I have yet to have any close passes whilst riding it. I think that the high riding position may really be helping to make the machine more visible to other road users. The sight of pedals flailing round at about eye level (for car drivers) certainly seems to give them pause for thought!
I've installed a SA 3 hub as a mid-drive, with an 11-28T 9s cassette. As configured presently it is approximately like having 45, 60, 80T chainrings, but that can easily be adjusted to give 29, 39, 52T instead. This setup gives instant access to low gears for starting (essential, I have found) and the drive can be easily reconfigured for touring or fast road work. As well as other cassettes at the rear I can replace the 3s hub with a 5s one easily enough, and indeed the mid-drive mountings will even accept a derailleur system up to 135mm wide. Thus a double derailleur system could give me (say) 6 x 9 gears. The front chain cannot come off, and the rear chain has yet to unship whilst riding the machine, even though I have not implemented the provision for chainguides. The whole drive is very quiet in use, and since most of the use can be in gear 2, and the chain runs are on large sprockets with straight runs, I would hope it is quite efficient, too.
So far as practicality goes, it is a yard and a half from the pedals to where you can put your feet down; I have found that sitting upright, unclipped, legs dangling, is the best way to approach tricky junctions, provided you can coast through them or intend to stop anyway. The steering is weird (to me) having a slight tiller component, and so far I can turn in about a 25 foot circle, feet up and pedalling; with practice I'd expect to get better than this. High speed handling remains a mystery to me; I've yet to venture over 25mph on it.
Although I hadn't exactly planned it, I have found that I can easily attach my carradice saddlebag to the rear of the seat, so I've already been able to use the machine for some utilitarian purposes. However I shan't use it too much more until I have made a better saddle arrangement.
All comments welcome!
cheers
I think it is fair to say that I am a life-long rider of 'normal' bicycles. Out of curiosity, I have tried recumbents in the past, and of course if you wish to go as quickly as possible, a low-slung recumbent position appears to be almost obligatory. But until recently the idea of owning such a machine did not appeal to me; they were for the most part expensive oddball machines, lacking in basic practicality.
Of particular concern is the perceived (certainly, if not actual, always) problem that a low slung machine may be missed by other road users. Having ridden a motorcycle for many years, I know all about that... and I know that the average motorist is looking out for other cars first, (lorries and buses too) slow-moving normal bicycles (if you are lucky) and then a third 'other' category. Rightly or wrongly, there is a perception that 'not being seen' may truly be a matter of oversight if you are riding a low-slung machine.
In the long term I have all kinds of mad ideas about much faster machines, but in the shorter term I realised that I would need a machine that I could use (much as I use an normal bike) with a recumbent position, just to train on and try a few ideas out. I looked at those you can buy and they seemed expensive (for what they are), mostly with a riding position that is lower than I'd like, and not particularly amenable to being messed about with.
So I decided to build my own '(very) high racer recumbent' machine.... starting with a motley assortment of knackered mountain bikes, and a few other odds and ends, I have built this;
Now the saddle is a lash-up... but this machine has 700C wheels and the seat height is much like that of a normal bike. When stopped, you can straddle the machine but only if the lowest part of the saddle is narrow enough to go between your legs. ( I still don't know if I will ever come to a happy compromise in this respect; all constructive suggestions welcome).
At first, I couldn't ride the thing at all, and I was seriously worried that I'd built something unrideable. But since then I've stuck with it and I've (over a period of about a week and forty-odd miles) become vaguely competent with it.
In terms of the design objectives, although it is early days yet, it appears to have worked, in that I have yet to have any close passes whilst riding it. I think that the high riding position may really be helping to make the machine more visible to other road users. The sight of pedals flailing round at about eye level (for car drivers) certainly seems to give them pause for thought!
I've installed a SA 3 hub as a mid-drive, with an 11-28T 9s cassette. As configured presently it is approximately like having 45, 60, 80T chainrings, but that can easily be adjusted to give 29, 39, 52T instead. This setup gives instant access to low gears for starting (essential, I have found) and the drive can be easily reconfigured for touring or fast road work. As well as other cassettes at the rear I can replace the 3s hub with a 5s one easily enough, and indeed the mid-drive mountings will even accept a derailleur system up to 135mm wide. Thus a double derailleur system could give me (say) 6 x 9 gears. The front chain cannot come off, and the rear chain has yet to unship whilst riding the machine, even though I have not implemented the provision for chainguides. The whole drive is very quiet in use, and since most of the use can be in gear 2, and the chain runs are on large sprockets with straight runs, I would hope it is quite efficient, too.
So far as practicality goes, it is a yard and a half from the pedals to where you can put your feet down; I have found that sitting upright, unclipped, legs dangling, is the best way to approach tricky junctions, provided you can coast through them or intend to stop anyway. The steering is weird (to me) having a slight tiller component, and so far I can turn in about a 25 foot circle, feet up and pedalling; with practice I'd expect to get better than this. High speed handling remains a mystery to me; I've yet to venture over 25mph on it.
Although I hadn't exactly planned it, I have found that I can easily attach my carradice saddlebag to the rear of the seat, so I've already been able to use the machine for some utilitarian purposes. However I shan't use it too much more until I have made a better saddle arrangement.
All comments welcome!
cheers