Author Topic: N+1 for 2  (Read 1137 times)

SoreTween

  • Most of me survived the Pennine Bridleway.
N+1 for 2
« on: April 05, 2020, 04:39:11 pm »
I guess it's about time I introduced the latest N+1 in the 'tween household:

Marvel at the 18 speeds
Glory at the matched pair of rusty chains
Gasp at the three, yes three almost useless brakes
Careful not to miss unmatched tube valves holding back almost no air!

All for just over the cost of a weeks tandem hire ;D

Will not be moving off our almost flat drive until those brakes are improved.

Should I match up the pedals or is it better with them slightly off?
2020 targets: None
There is only one infinite resource in this universe; human stupidity.

Phil W

Re: N+1 for 2
« Reply #1 on: April 05, 2020, 05:22:25 pm »
Match them up as it makes setting off and stopping easier.

Kim

  • Timelord
Re: N+1 for 2
« Reply #2 on: April 05, 2020, 05:24:42 pm »
Having some TSO experience, I can't help but notice the lack of a 'suspension' fork or sonic disc brakes.   :thumbsup:
Careful, Kim. Your sarcasm's showing...

SoreTween

  • Most of me survived the Pennine Bridleway.
Re: N+1 for 2
« Reply #3 on: April 05, 2020, 05:52:56 pm »
Cheers Phil, I'll match 'em up.

Having some TSO experience, I can't help but notice the lack of a 'suspension' fork or sonic disc brakes.   :thumbsup:
A TSO it most certainly is (note the pic file name), you name it, it doesn't have it.
One thing it does have is a wierd split pilot bb housing.  And a timing chain like a piano wire, so much so I'm surprised it measures <.5% stretched.  The gear chain is >.5% & <.75% stretched.
I have a feeling the sheer quality of the thing has ensured it hasn't seen a lot of use.

I'd already lightened it before it was fully in the back of the car, this was achieved by the water in the stoker seat tube pouring out.  I hope it's a blind tube not open to the bb!
2020 targets: None
There is only one infinite resource in this universe; human stupidity.

Re: N+1 for 2
« Reply #4 on: April 05, 2020, 07:01:23 pm »
The pilot bb shell is split to make adjustment of the eccentric bb hub to adjust the chain tension easier.

The bb shell on my custom Moulton tandem wasn't split originally, and it was extremely difficult to rotate to adjust. Recent attention by the framebuilder included splitting the shell.

(Because I often switch between solo and tandem configuration, I have to adjust the connecting chain tension each time to get it on and off).

SoreTween

  • Most of me survived the Pennine Bridleway.
Re: N+1 for 2
« Reply #5 on: April 06, 2020, 08:16:22 am »
Ah thank you orienteer, I was wondering how timing chain tension could be adjusted  :thumbsup:

I do like a learning day :)
2020 targets: None
There is only one infinite resource in this universe; human stupidity.

Re: N+1 for 2
« Reply #6 on: April 06, 2020, 10:03:46 am »
Does having two rim brakes on the rear achieve anything? I thought tandems normally had a hub brake to limit heat fade / tyre burst as the rims warm up?

LittleWheelsandBig

  • Whimsy Rider
Re: N+1 for 2
« Reply #7 on: April 06, 2020, 10:12:14 am »
A big drum drag brake used to be commonplace on touring tandems in the mountains to stop overheating rims but Arai drum brakes haven’t been made for well over a decade.

Big heavy Al rims prevent rim overheating on rim brake tandems, particularly deep aero Al sections. The brake pads can start to melt anyway, unless carefully selected. Cheap tandems usually aren’t equipped thoughtfully.

Dual rim brakes on the same rim does help on wet descents, ensuring the rim is dry for reliable speed control.

The second rear brake is usually because the captain’s hands get tired dragging a brake down a long descent. Some tandems hook up a captain’s gear lever as a drag brake actuator, some tandems give the third brake to the stoker.
Wheel meet again, don't know where, don't know when...

SoreTween

  • Most of me survived the Pennine Bridleway.
Re: N+1 for 2
« Reply #8 on: April 06, 2020, 02:29:51 pm »
Timing chain adjusted to 12mm-ish movement, thanks again orienteer and Charlotte's Tandems.  A very simple job.  Cranks also aligned.
Squirt of Dinitrol ML down the stokers seat tube.
Brake pads de-glazed on some course emery paper and several bits of what looked like aluminium swarf removed.  Brake pivots cleaned up & lubricated and brakes adjusted.  Not terribly effective as the only adjustment on the spring return is the choice of 3 holes to locate the fixed end of the spring.  Also the brakes are the type where the cable connects to one lever and a fixed short piece connects from the yoke to the other lever.  These always pull unevenly.  Still, they feel better now.
There is huge lateral play in the hubs but that's a problem for another day.

With that we mounted up and had a wobble, lots of wobbling.  Mrs Tween has only cycled a few times in her life so this was always going to be eventful.  But after a dozen times up & down the garden & drive the terrified screaming behind me changed to our first 'wheeeee' :)
2020 targets: None
There is only one infinite resource in this universe; human stupidity.

Kim

  • Timelord
Re: N+1 for 2
« Reply #9 on: April 06, 2020, 02:46:18 pm »
Mrs Tween has only cycled a few times in her life so this was always going to be eventful.

That can actually help.  Inexperienced stokers who are cyclists tend to steer.
Careful, Kim. Your sarcasm's showing...