Mark II recumbent. First ride today.

Recumbents and all feet forward machines

Mark II recumbent. First ride today.

Postby RosscoG » Sat Feb 06, 2010 2:13 pm

Ive been posting at bentrideronline about this project although thought I better put a post up here for the locals too.
Pretty happy with the layout now. Still tossing up whether to put a CF version together or just put some better gear into this one and call it my permanent ride, odd as it is.

Had a great first real ride today. Only a couple of breakdowns. (Crank fell off, oops)
Bit sore, as i havnt developed my bent legs yet.
Good speed other than the hills, which is mostly an issue with the engine.
If anyone see's me around Brisbane, please do pull along side and say Hi. I have enjoyed meeting and riding with a lot of people already, as it sure attracts some attention.

Rossco

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by BNA » Sat Feb 06, 2010 5:00 pm

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Re: Mark II recumbent. First ride today.

Postby Freddyflatfoot » Sat Feb 06, 2010 5:00 pm

Thanks for the post Rossco.
have to admit, I missed it on BROL!
Looks like a very interesting MBB FWD. Be interested in hearing what else you have in mind. looks very innovative.
Cheers!
Rob
---------------------------------------------------
Homebuilt trike, with electric assist
26"/20" trike, "Goanna"
SWB recumbent, 700C/451 , "Kookaburra", homebuilt.
FWD project (Cyclone).
Optima Raptor
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Re: Mark II recumbent. First ride today.

Postby RosscoG » Sat Feb 06, 2010 6:45 pm

Thanx,
For now, i'm just tweaking then tweaking then rebuilding the bits that i cant tweak any more.
Its pulling to the right so i am chasing that before going further. Something is out of true (most of it probably), very frustrating.

Next I am looking into air shocks with some rebound control, adjustable preferably. With the trailing front suspension at such a high angle, the snap back after a big bump can bounce the front wheel, not ideal. BUT, wow they are expensive. Anyone know of a cheaper option?

Very shortly i would like to put some some decent drive gear in there. It is cheap, nasty, old MTB stuff atm and I need more! I spin out at about 60kph at the moment with plenty more to go, so I hope to add some to the top end as well as get some much smoother gears. This bike is a little scary at this speed tho, so that is not an absolute goal.

After that, who knows... mmm a smooth integral seat, carbon fibre lowracer with 700's...... mmm

Rossco
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Re: Mark II recumbent. First ride today.

Postby Freddyflatfoot » Sat Feb 06, 2010 8:28 pm

Scary at 60? Thats a worry! My low racer is nice and stable at spped, currently top speed is 83 kph. Could go quicker if I had longer downhill runs!
My gearing pretty much spins out in the 60's, but IMO, that's ok. I would rather have the close gear gaps in the range where I'm actually pedaling!
BTW, do you really need the front suspension? You could try it without. You might be pleasantly surprised, and might find you can get the power to the road more efficiently. IIRC, the top end Cruzbike, only has an elastomer suspension block in the headstem.
Cheers!
Rob
---------------------------------------------------
Homebuilt trike, with electric assist
26"/20" trike, "Goanna"
SWB recumbent, 700C/451 , "Kookaburra", homebuilt.
FWD project (Cyclone).
Optima Raptor
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Posts: 237
Joined: Mon Jun 30, 2008 8:50 am
Location: Ballarat, Victoria

Re: Mark II recumbent. First ride today.

Postby }SkOrPn--7 » Sat Feb 06, 2010 8:42 pm

Rossco thanks for sharing your creation over here and I must say it is an interesting build/design keep us updated in your trouble shooting and problem solving so we can all learn and good luck in tweaking.
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Re: Mark II recumbent. First ride today.

Postby RosscoG » Sat Feb 06, 2010 9:22 pm

Only got hairy because it was very rough and i didn't have a lot of room to maneuver. I think i could go faster on a good hill on a nice surface, wow, 83 mine will not do that, thats for sure. I will do a lowracer one day, although i just couldn't justify it now. This one feels low enough around other bikes as it is.

Suspension, y, it is necessary. I tried first with standard forks, not bad for handling on the smooth although traction is bad. Power to the ground relies on keeping contact with it. Traveling along even a cemented path i could feel each expansion crack through the drive, just slipping a bit. Then there is driveways, going up one of those under power lost over a 1/4 turn, a full stroke at some speeds.
These forks had quite some curved rake making handling badly twitchy, so i spun them around for serious trail, which worked, although made the skipping worse and the forks would have failed in this arrangement.
After this, i used some MTB shock forks as pic below. This worked well, although would need a lot steeper head tube angle as i was getting stress fatigue in parts.
I know this approach was over the top, although it has sure been an interesting excersise. I can put this bike into, over, across anything and it just makes a horrid noise and deals. And it has served me well at least twice now. Once with the MTB forks, i got off the side and then realised there was a big ditch in the cement, i think the non shocked forks would have crumpled that time and again since in the current arrangement.
I agree, there could be a lot done differently in a race version, although this is more my all terrain model ;)

Older version really roughly assembled to test the layout.
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Re: Mark II recumbent. First ride today.

Postby JulianEdgar » Mon Feb 08, 2010 10:08 am

Next I am looking into air shocks with some rebound control, adjustable preferably. With the trailing front suspension at such a high angle, the snap back after a big bump can bounce the front wheel, not ideal. BUT, wow they are expensive. Anyone know of a cheaper option?


Consider using an airbag plus pressure bottle see - http://www.bicycles.net.au/forums/viewtopic.php?f=29&t=13832

The amount of damping control you can get is high. Note I had to modify the airbag pressure connection (increase it in diameter) so it's not a straight off the shelf fitment.
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