High Roller frame size

Joined
Oct 19, 2012
Messages
799
Location
Wakefield, UK
I've been using these:-


They are just the right width for a chain. You can also get them in singles on both ebay and Amazon. The downside is the 15mm inner diameter bearing with 15mm bolts a rarity but you can get a 15mm to 12mm adapter for a mountain bike front axle from ebay for a couple of ££.

A lot of pulleys have "V" grooves which are not ideal. You want a flat bottom or a toothed pulley.
 
Joined
Oct 28, 2019
Messages
10
Location
Sydney Australia
Latest update:
I have now test ridden the bike, or more correctly rolled the bike downhill, appropriately for the High Roller!

Wasnt game to lift my feet too far from the ground and onto the pedals. It is much harder to ride than a conventional bike.
The faster I went the more stable it seemed but I will need a lot of practice, anyone put training wheels on one?
https://flic.kr/p/2ihqqLA
Checked the head angle and its within 0.1 degree of the 73degrees called for in the plan, havent measured the trail as yet but since I used a pretty standard mountain bike fork it should be OK.

I made rollers ( as suggested) out of polyethelene chopping boards and ball races (from Bunnings for OZ viewers).
But ended up not using them, as yet anyway.
https://flic.kr/p/2iinApf
When I assembled it I found the chain missed the seat when it goes straight from the chainwheel to the rear cluster.
I have it going through a bit of plastic water pipe which stops it rubbing on your leg as well the front brake cable which I will secure back closer to the frame.
In the photo its not under tension but the tube can float up and swivel to align with the chain.
The chain return from the derailleur to the chainwheel currently uses a second derailleur idler ( as suggested in the plans) to guide it high enough to clear the front wheel. It is not welded to the frame but can pivot to align with the chain. I might cut the second wheel off it as its not necessary I think.

https://flic.kr/p/2iir8Y5
I have read that sometimes with suspension you get bobbing if the chain doesnt go through the line of the suspension pivot point, since the suspension is pretty stiff I dont think this will be a problem and anyway I have a roller to use if it is.
https://flic.kr/p/2iipZpc
The handlebars can be tilted so that I can fit the bike in the back of the car, they can also be tilted forward and back if needed for comfort.
The seat which is on angles and can slide along the frame but will be bolted on when Im happy with the position and also allows it to be removed for transport.
Id like to use skewers to secure them both, on one of the other threads this was being discussed.
https://flic.kr/p/2iipY1f
Skewers 5mm dia and about 50mm long is what I would need, does anyone know if its possible to get them that size.

Yet to be done are the rear brakes and cables for it and the derailleur, its just wired into a middle gear at the moment.

Regards
Stewart
 
Joined
Feb 7, 2008
Messages
2,538
Location
Nottinghamshire England
Checked the head angle and its within 0.1 degree of the 73degrees called for in the plan, havent measured the trail as yet but since I used a pretty standard mountain bike fork it should be OK.

Regards Stewart
OK first up if you hold the back of the seat and push the bike forward does it :-

A) front wheel swing suddenly left or right and cannot be corrected by simply tilting the seat back in the opposite direction ?

If yes trail is wrong

or

B) bike can be pushed and steered by tipping rear of seat left or right trail is ok

All forks are different some are dead straight and some have a bend and some have straight offsets.

the rest is riding experience :D
 
Joined
Oct 28, 2019
Messages
10
Location
Sydney Australia
Thanks for the replies.
The trail is OK as it responds correctly to tilting the seat side to side as in B in Stormbirds post above, though
the headset bearings might need a bit of greasing to make it smoother.
I looked up the links mentioned in the "building a woodie" thread on AZ. One of these links was to a http://www.wisil.recumbents.com page which calculates suggested trail dimensions for recumbents.


Putting in the values for my High roller it suggests for normal handling the trail should be about 10.5cm, and 15 cm for "freight train" and 5.3cm for "jet fighter"

You can also plug in the geometry of your bike to give its actual trail, on mine its 6.1cm.

This is closer to "jet fighter" than normal so I guess the issue is the rider since Im not a jet fighter pilot.
I could experiment by removing the spring and installing a shorter compression strut which would increase the head angle and thus the trail. Might do this and try it when it stops raining.
However I think it is probably a matter of getting more experience in riding it.

Did anyone else here find riding a 2 wheel recumbent harder than a conventional bike?

Regards
Stewart
 
Joined
Feb 7, 2008
Messages
2,538
Location
Nottinghamshire England
When you do ride it can you feel the individual pedal strokes moving the handle bars slightly ?

If yes you probably need a little more trail.

Of course being new to a recumbent nuances like that are hard to judge when you have a death grim on the bars and are hanging on for grim death :D

A compression strut is a great idea leaves the wheels and so the brakes alone so you can still ride it safely.
If you made it adjustable maybe one tube inside another you could explore a few different lengths at the same time.

I tamed a ' jet fighter ' by adding more rake with different forks , changed something that needed constant steering corrections and was a handful trying to ride single handed whilst signalling etc into a bike that could be ridden a short distance with the hands off the bars [ I do not recommend this except for testing purposes ;)]

At the end of the day there is no substitute for seat time ......

if the height is scary try either 24" or 20" wheels
 
Joined
Feb 20, 2013
Messages
682
Location
Axedale, Victoria, Australia
Website
axerail.coffeecup.com
I would not like to attempt to ride any commercial MTB that I have ridden in recent years without holding the bars. Use to be able to do it once but I am convinced that bike design has changed somewhere along the line. The ones I have tried seem to become instantly unstable to the point where I have not been able to go "Look Ma, no hands!" Not a good idea anyway. You are just that little bit further from recovery if something happens - like a stone under a wheel.
 
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