[python] Re: (no subject)

  • From: Henry Thomas <whpthomas@xxxxxxxxx>
  • To: python@xxxxxxxxxxxxx
  • Date: Wed, 4 Nov 2009 17:15:38 +1000

Hi All,

It has been a long time since I have posted, I generally follow the list, but I am in my last year of my PhD so have been very busy. On the question of whether or not to build a tilting trike, I feel I have some personal experiences that may be worth contributing. I will start by saying that I do love riding my tilting trike, personally it was a technical accomplishment that I always get a kick out of, and it gets a lot of attention. That being said, from the point of view of being the right bike for my commuting needs, it has been an abject failure. It is rather heavy, has low visibility in traffic and on the increasingly busy roads I started to feel less and less safe. I also got hammered by the bumps. Trikes have three contact patches, so when there are rough spots it is very hard to avoid them. The rear suspension has helped, but crossing tram lines with 100psi tires at any reasonable speed is brutal.



So last Christmas holidays I went back to the drawing board. I started from scratch by listing all the things that I wanted my bike to be able to do for me.

- it wanted a recumbent because that did not put any pressure on my hands (I have very bad RSI)
- it had to have full suspension to compensate for high psi/low rolling resistance on bad roads
- it should weigh as little as possible
- it should have a clean/uncomplicated chain line
- it should allow me to cycle with other road bike riders on the weekend and not feel like the poor cousin - I wanted to be at their eye level.

After quite a bit of doodling I realised that I didn't want a tilting trike, or a low racer, or a SWB. I ended up with the LWB design you see above. I drafted the plans in Solidworks, and two weeks later I was riding around on my new bike - it worked first time - I call it the Longbow. The suspension is awesome, a natural frequency of 1.3hz on the front and 1.6hz on the back, which means they both list together if I go over a speed bump at 28kph - no hobby horsing. The chain-line is clean, and the gear rations are perfect for the kind of riding I do, flats and rolling hills. It is not a steep hill climber, but there aren't any where I live.

So have I gone off low racers and tilting trikes? No, I still plan to build a few more, I would also like to build a rear wheel steer bike. But for my daily commute and for social rides on the weekends, it turns out that this new bike is perfect. We did a 130k ride a few weeks back, and while I had saw legs, the other guys on road bikes really had an uncomfortable ride for the final 40k or so. As I said, this things is amazing on corrugated dirt roads and chewed up bitumen a speeds above 20k, which is exactly what I needed it for.

Now getting back to the original question, should you build a tilting trike - what I would say is that this is the wrong question, start with a list of things you want your new trike/recumbent to be able to do, then ask us to help rule out the designs that won't give you the things you need. I have always found this forum a great place to get feedback on whatever design you ultimately choose to build.

Wishing you all the best in your adventure.

Warm regards to everyone.

-h

On 03/11/2009, at 4:24 AM, Marcel Maatman wrote:

Hi,
 
Maybe the solution of Bram's Tilting Trike will do?
You can go to his site: www.fastfwd.nl It has an English part .
Als trike builder Henri Thomas has a lot of information. He has used the Python  design for his Jetrike.
A lot of succes!
 
greetz
Marcel (Twello, the Netherlands


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