Pictures of your recumbent

DIscuss anything relating to non-standard cycles and their equipment.
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Cunobelin
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Joined: 6 Feb 2007, 7:22pm

Re: Pictures of your recumbent

Postby Cunobelin » 29 Apr 2015, 8:01pm

firedfromthecircus wrote:Is yours 2 or 1 wheel drive? Am I right in thinking the 2 wheel drive differential is quite recent?

After looking at your picture I decided to price up a Kett, just for interests sake you understand!
I specced it as I would like it, so Rohloff, 2wd, dynamo hub, schlumpf etc. :shock:
Suffice it to say I will not be ordering one this week! :lol:


Mine has the Rohloff and the differential.

My only issue is the Rohloff mounting

There are two bars that the Rohloff mounts to, and one slips.

After about 80 miles you have to readjust the mount or the secondary chain comes off

It seems to be an issue as most of the Rohloff images show the same marks where the movement scratches the bar

This is a random image from Google showing the issue

Image

hercule
Posts: 986
Joined: 5 Feb 2011, 5:18pm

Re: Pictures of your recumbent

Postby hercule » 29 Apr 2015, 10:33pm

firedfromthecircus wrote:Is yours 2 or 1 wheel drive? Am I right in thinking the 2 wheel drive differential is quite recent?

After looking at your picture I decided to price up a Kett, just for interests sake you understand!
I specced it as I would like it, so Rohloff, 2wd, dynamo hub, schlumpf etc. :shock:
Suffice it to say I will not be ordering one this week! :lol:


Mine's a two wheel drive. The differential has been around from before the current series, it was an option on the pre-2005 steel framed models and standard on the "off road" verision, the Kettwiesel Ride (diff+front suspension fork+knobbly tyres).

We had a steel version before this one, when I wanted my own one I knew that I wanted the triple chainset (I didn't get on with the Schlumpf Mountain Drive) and the differential to avoid the front wheel hop the one wheel drive version experiences on steep hills (there are techniques for avoiding it). The lighting is actually via an AXA rim dynamo running off one of the back wheels, but I acquired a cheapo Shimano dynohub - it is pretty weighty so it tends to come on an off according to seasonal requirements.

When I got mine (2007) prices were not far off a kitted out Trice, shortly after that the £ plummeted against the € and they became very pricey!

Geoff.D
Posts: 1959
Joined: 12 Mar 2010, 9:20pm

Re: Pictures of your recumbent

Postby Geoff.D » 30 Apr 2015, 9:33am

Cunobelin wrote:There are two bars that the Rohloff mounts to, and one slips.

After about 80 miles you have to readjust the mount or the secondary chain comes off


Are you saying that that you have to readjust the mount after every 80 miles or after the first 80 miles from fitting? If it's the former, it seems out of kilter with the high level of engineering of the Kett and Rohloff. Whilst not a big job to readjust, for me it would be about every (riding) day and a half that I'd need to do it. Faffy and time consuming. I think I'd feel a bit miffed that they haven't found a solution.
Last edited by Geoff.D on 30 Apr 2015, 3:33pm, edited 1 time in total.

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squeaker
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Location: Sussex

Re: Pictures of your recumbent

Postby squeaker » 30 Apr 2015, 9:43am

Cunobelin wrote:My only issue is the Rohloff mounting

There are two bars that the Rohloff mounts to, and one slips.

That's diabolical - definitely the work of Stan :evil:

Needs a material change to alter both the coeficient of friction between bar and clamp, and the clamp strength to increase clamping loads....
"42"

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[XAP]Bob
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Re: Pictures of your recumbent

Postby [XAP]Bob » 30 Apr 2015, 9:45am

Trying to work out *how* it slips - since there would appear to be a pretty strong tension in both directions.

Then realised that the rolhoff is of course a torque convertor, so one chain set will see FAR higher tension, and a lower chain speed, than the other. But the tension is all that matters in terms of sliding along the rails.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Geoff.D
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Joined: 12 Mar 2010, 9:20pm

Re: Pictures of your recumbent

Postby Geoff.D » 30 Apr 2015, 3:41pm

[XAP]Bob wrote:Trying to work out *how* it slips - since there would appear to be a pretty strong tension in both directions.

Then realised that the rolhoff is of course a torque convertor, so one chain set will see FAR higher tension, and a lower chain speed, than the other. But the tension is all that matters in terms of sliding along the rails.


If I understand you, Bob, you're saying that there'll be a difference in tension between the input chain and output...and this resultant causes the slippage?

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[XAP]Bob
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Re: Pictures of your recumbent

Postby [XAP]Bob » 30 Apr 2015, 3:52pm

Geoff.D wrote:
[XAP]Bob wrote:Trying to work out *how* it slips - since there would appear to be a pretty strong tension in both directions.

Then realised that the rolhoff is of course a torque convertor, so one chain set will see FAR higher tension, and a lower chain speed, than the other. But the tension is all that matters in terms of sliding along the rails.


If I understand you, Bob, you're saying that there'll be a difference in tension between the input chain and output...and this resultant causes the slippage?



Yes.

The output chain is at a fixed gear with the rear wheels, the input chain is at a fixed gear to your feet (ignoring chainrings for the moment)

I will assume that the input and output sprockets are the same size (I know this is a bit off, but bear with me)
I will also assume that "direct drive" (or close to it) is in the middle of the gear range (haven't looked it up)
In general the input chain speed and tension are approximately constant (simplification of the pedal stroke, but you get the idea).
The speed of the chain doesn't matter in terms of the tension force that is exerted on the hub (through the sprocket) and the return side of both chains is assumed to have zero tension.

In a low gear (slow wheel speed) the output chain is transmitting the same power (assuming no loss in the IGH) through a much slower moving chain - this is therefore at high tension, and there is a net force (OutputTension - Input Tension) pulling the hub rearwards.

In the direct drive (medium wheel speed) case the input and output chains are moving at the same speed and (assuming no loss in the IGH) the same tension, so there is no net force and all is well with the system.

In a high gear (high wheel speed) the output chain is transmitting the same power (assuming no loss in the IGH) through a much faster moving chain - this is therefore at low tension and the net force (same calculation as above) is negative - i.e. the force is acting to pull the hub forwards.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

lukehall
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Joined: 3 Sep 2013, 9:44pm
Location: Cambridge, UK

Re: Pictures of your recumbent

Postby lukehall » 5 May 2015, 11:17pm

Image
Last edited by lukehall on 6 May 2015, 7:12pm, edited 1 time in total.

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[XAP]Bob
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Re: Pictures of your recumbent

Postby [XAP]Bob » 5 May 2015, 11:48pm

Image no worry - probably ends drop box to be logged in...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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[XAP]Bob
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Joined: 26 Sep 2008, 4:12pm

Re: Pictures of your recumbent

Postby [XAP]Bob » 6 May 2015, 5:50pm

Worry is iOS for showing btw.

It needs a Dropbox login to view...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

lukehall
Posts: 37
Joined: 3 Sep 2013, 9:44pm
Location: Cambridge, UK

Re: Pictures of your recumbent

Postby lukehall » 6 May 2015, 7:12pm

hopefully that now works

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[XAP]Bob
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Re: Pictures of your recumbent

Postby [XAP]Bob » 6 May 2015, 7:51pm

Yep. Interesting side bags...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

BlackPanther
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Joined: 3 Jan 2012, 11:24am
Location: Doncaster

Re: Pictures of your recumbent

Postby BlackPanther » 16 May 2015, 6:31pm

Image
The photobucket images don't work !!!

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[XAP]Bob
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Re: Pictures of your recumbent

Postby [XAP]Bob » 16 May 2015, 6:50pm

Is that new BP?

I ought to grab a shot of mine before I start modding it....

Ordered a dynamo hub for the rear and a new hub for the front, both take centre lock discs.
I tend to enclose the rear wheel after building, maybe with red abs though - since I have a red tail box :)

Also a toplight line small (really tiny rear light) and a Lyt for the front.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Indeboat
Posts: 121
Joined: 4 Oct 2012, 5:59pm
Location: Derbyshire

Re: Pictures of your recumbent

Postby Indeboat » 23 May 2015, 6:07pm

Hello Everyone
Just finished making my Atomic Zombie Warrior Trike(4 Weeks),done about 120miles on it at the moment,slight tweakes to the seat and cutting some weight off bolts, pulleys and the seat.
Rides very nicely ,Shimano XT 9 speed setup, triger shifters work very well and ergonomicaly spot on.
Avid hydraulic discs.
In my haste to build the trike i bought 20" rims and disc hubs from the USA ,but did not realise that there are two types of 20" rims :oops:
Bought stainless spokes from the UK and built the wheels
My rims are 451 ,but with the Shwalbe Durano tyres it works very well.
The seat closed cell foam is a bit on the hard side so i have removed small amounts from contact areas, also mounted the rear of the seat via a rubber shock absorber bush(works very well).
Hope to get out to Ely for a ride next week.
Richard

Image