That transverse bar at the front of the trailer....ooooh....there's got to be a more elegant solution?
CityCyclingEdinburgh Forum » Questions/Support/Help
'Bike' trailer - Is this a mad idea?
(87 posts)- Started 7 years ago by HankChief
- Latest reply from HankChief
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Posted 7 years ago #
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Uberuce made reference to an 84 or 86-litre crate for his Carry Freedom, though I don't recall which size trailer he used.
I think he referred to is as the "80 litre plastic jobby".
If memory serves me correct he has the same wide version of the trailer as me, although we don't have the fancy new load platform.
Posted 7 years ago # -
@Iwrats. Thanks for the input. I plan to cut down the x-roof bars and make good any sharp ends. Hankchief has concerns over the overall width of the trailer and its load.
All suggestions much appreciated.
Posted 7 years ago # -
@biketrain
It'd be good to see it, but I was thinking;
1) CoG of the carried bike ought to be directly over the trailer axle.
2) The clamping system on those Thule style bars is designed for a roofrack, which we don't actually need here.
3) I'd look at using coach bolts to fix the bike carrier to the trailer base directly.Posted 7 years ago # -
Apparently there is a Euro Standard for crates. Who knew...
So 600 * 400 seems the norm. I could fit 2 on it they were sideways or 1 comfortable longways.
If I go with the standard size it will be easy to get replacements.
Next question: ventilated or solid sided?
I'm thinking ventilated for reduced wind resistance ;-)
Posted 7 years ago # -
Go ventilated as you can get some good dry bags now of all sizes. Spotted a boat being towed on M6 yesterday wrapped in industrial strength cling film). Also had loose stone for my drystane dykes which I had stacked on pallets (four tonnes) delivered wrapped in cling film. If you are thinking of bike delivery side line?
Posted 7 years ago # -
@IWRATS
Thanks for your input you have got me thinking about the design again.
1) CoG of the carried bike ought to be directly over the trailer axle.
Good point. The Longitudinal Centre of Gravity is in front of the trailer axle.
Hankchief and I measured the hitch weight with the bike racks positioned as shown in the pictures.
Results of hitch weights,
With no bikes = 2 kg
With 1 bike = 4 kg
with 2 bikes = 6 kgMax hitch weight ~ 8kg
As Hankchief will be often towing the trailing with his tandem and no stoker then it is important that we get some weight on the rear wheel of the Helios. With the power he can produce, we do not want to see him doing burnouts on the Glasgow Road.
I think we are comfortable with the balance of the trailer. If in practice the CoG is in the wrong place then we can always add training weights. HC will be missing his ‘Training Weights’ when the Chieflets cycle to school.
2) The clamping system on those Thule style bars is designed for a roofrack, which we don't actually need here.
If there was only to be one bike rack attached to the trailer on the load carrying side, I would do this and mount it backwards ( using coach bolts, as you suggested in point 3). However this carry freedom will need to be able to take one or two bikes and be reconfigurable in the field.
The Thule bar serve a number of uses in this case.
a. They bring the CoG forward longitudinally for balance, see point 1.
b. They allow the bike carriers to clear the trailer frame, this would not be an issue were it not for the fact that we are mounting the bike racks to the underside of the trailer.
c. They allow the bike carrier’s position to be adjusted, tool free. They can be slid across the trailer to allow two bikes to be carried or when one bike is to be carried the active bike rack can be moved towards the centre line of the carry freedom. This will allow the Transverse Centre of Gravity to be midpoint between the wheels..
3) I'd look at using coach bolts to fix the bike carrier to the trailer base directly.
Good point. These would allow a relatively smooth surface on the load carrying side.
I have decided to use pronged t-nuts. These will sit flush with load carrying surface and allow the Thule bars to be removed and re-installed easily. My experience of coach bolts is that they tend to chew up the timber they are mounted and then remove to many times. They are great for fit and forget applications.
I am using Allen key headed bolts to connect the Thule bars to the trailer. This will allow the bike racks to be slid along the transversely without catching and bolt heads.
IWRATS Thanks for your input, you have made me thing through the design and enhance it. Nuts and bolts now ordered. Proof will be in the pudding.
The next design challenge will be selecting and mounting lights that will be legally the right way up when the trailer in the standard or upside down mode.
Also need to consider the flag(s). Should these be gimbal mounted?
Posted 7 years ago # -
With the power he can produce, we do not want to see him doing burnouts on the Glasgow Road.
Can we put that one to a vote?
Posted 7 years ago # -
IWRATS Thanks for your input, you have made me thing through the design and enhance it
My absolute pleasure @Biketrain, and thanks for the detailed post. Really looking forward to seeing this hitched to its locomotive, which I suspect is entirely capable of spinning up the rear wheel....
Posted 7 years ago # -
It is now mostly built. Just tidying up a few rough edges. Then the next stage will be to 'Pimp my Ride'.
Any suggestions welcome. Gimbal mounted flag etc.
Hoping to do a grand reveal on Friday at the 'PY or not PY'. Interesting to see if it can carry a herd of Elephant bikes. Is two a herd?
Posted 7 years ago # -
Uh oh...
Our secret plans have been leaked and copied by those pesky Mancunians...
Posted 7 years ago # -
But which bike is towing?
Posted 7 years ago # -
Don’t tell Hankchief but I have been testing out his trailer. On Sunday I needed to collect minibiketrain and midibiketrain from the next village. They had been to a sleepover so I would need to take their bikes and bring back their cases.
I duly loaded two mountain bikes on the trailer and loaded a pannier with tie down straps and plastic hats.
I used my ‘Protest Bike’, as seen as POP and other protest rides, as it is heavy and has low gearing. For the purposes of this post I use the term TUG. RIG means tug + trailer.The route was mostly downhill so the weight was not an issue; however the trailer bullies the Tug a little causing some uncomfortable oscillations. It was as if someone was alternatively pushing and pulling on my bike. This may be due to the high centre of gravity of the load. I had no issues the role stability, but I was careful when going up and down curbs to make sure both trailer wheels were perpendicular to the curb.
Braking was not a major issue but did take longer than normal. I would be useful to have some kind of parking brake on either the tug or the trailer. I found that the act of loading the trailer can cause the while rig to move and the tug fall over.
The other concern would be the getting through barriers both deliberate and consequential. At the end of a long downhill mixed use gravel path I was confronted with a sharp turn and a narrow gateway. Only by pushing the tug wide into the bushes was the trailer able to get through the gateway. Even then I did pick up some foliage.
On arrival, at the friend’s house I was greeted by midibiketrain with "We cannot cycle home. We have cases" and water pistols in turns out. Within 2 minutes I had the bikes unloaded and the trailer flipped over into load carrying mode. Admittedly I then had to move the tow hitch from one side of the tug to the other. It did not take long to load up the cases; however HankChief will need to get himself a selection of straps and bungees. There is no telling what he will carry in the future.
On the return trip it was quite a challenge to manage the younger riders. Some of the pavement they need to push along was too narrow for the rig, so I would need to give clear instructions and then then cycle up the road to the next meeting point. On occasion this meant, being on opposite sides of the road. Trailer was easier to pull with the lighter load and a lower centre of gravity.
On first impression this is a workable solution to Hankchief’s needs. There is the overhead of needing to be a skilled and powerful rider and planning non-road routes very carefully. Anther anomaly will be the port and starboard turning circle will vary dramatically depending on which way up the trailer is and hence the position of the drawbar. Again good route planning will be needed.
I look forward to HankChief doing the ‘First’ trial.
Trailer carrying two bikes by Bike Train, on Flickr
Trailer loaded with luggage by Bike Train, on Flickr
Negotiating a narrow gateway by Bike Train, on Flickr
Checking ground clearance by Bike Train, on Flickr
Posted 7 years ago # -
It was as if someone was alternatively pushing and pulling on my bike.
I get that with a full load in my off-road trailer, which is only 27kg all in. Like you say, seems to make no practical difference but feels weird.
There is no telling what [HankChief] will carry in the future.
Understatement of the year.
Posted 7 years ago # -
the trailer bully the Tug a little causing some uncomfortable oscillations
Having towed home very heavily laden trailers of freshly chopped firewood home downhill a few times now, this "troublesome trucks" effect seems to be what happens when you take a heavy trailer for a tow and try to slow the whole lot down with brakes at the front of the consist only.
Basically it's one of the main reasons why unfitted (i.e. no brakes on the wagons) trains require a brake van at the end.
Posted 7 years ago # -
the trailer bullies the Tug a little causing some uncomfortable oscillations
My trailer does this too, but I presumed it was because the drawbar connection to the trailer chassis is worn and rattles/flexes according to one's cadence.
InnerTuba's (recumbent trike towed) trailer has drum brakes that are operated on demand by a special headrest, but most designs have a sprung connection at the gooseneck which uses the deceleration of the towing vehicle to activate the brakes on the trailer.
Posted 7 years ago # -
the trailer bullies the Tug a little causing some uncomfortable oscillations
I've noticed this effect with revolution roller (child trailer) but not the revolution cargo. I had put this down to the difference in hitches. The roller uses spring in the single sided hitch to allow flex which has all the drawbacks Biketrain mentions, including potentially tipping the tug.
The Cargo uses a U hitch which attaches to both sides of the rear quick release. It articulates vertically there and horizontally where the bottom of the U attaches to the trailer. It doesn't have the same push pull feeling of the roller so I had assumed it was the nature of the hitch which caused the issue.
Posted 7 years ago # -
Did a dry run today (without anything on the trailer) and it worked well, albeit over 4 metres in length.
Made it through the tight gate we were worried about on page 1 of the discussion, without too much bother.
Even got some approving words from R Smart for the 'contraption' as I was unlocking after MCC.
Passenger & bike carrying runs to follow...
Posted 7 years ago # -
First proper run today and it was a success. Hard work on the hills but kept a good pace on the flat and fitted through all the gaps.
You'll be pleased to know that I did wheelspin on SJR (but it was on a shiny draincover rather than roar powaaaaah :-)
Minichief will need to build up some stamina so we will be building up to 5 days a week. Who's going to spot us first?
Posted 7 years ago # -
Spotted and exchanged waves this morning.
I don't have the vocabulary to describe how awesome this is. Needs to be seen to be believed.
Posted 7 years ago # -
@stickman.
Was the trailer carrying a bike when you spotted HC?
Posted 7 years ago # -
It's this awesome.
No, it's this awesome....
Posted 7 years ago # -
@biketrain: yes
@iwrats: yes
My one suggestion for an upgrade would be a small speaker system that could blast out Ride Of The Valkyries.
It also needs a name. "BigRig" no longer captures it.
Posted 7 years ago # -
Another spot this morning came whilst mini chief was cycling, from the School's Head teacher.
Posted 7 years ago # -
I've had a trailer rig for bike carrying for past 20 years - uses the commercial quality rapid loading (<7 seconds) bike trays for buses and single wheel. Minor (bending) issues to resolve with the bracing of the connection of swan-neck on to the trailer 'chassis'. When not carrying bikes has carried fridges, flatpack furniture, stock timber, & polypropylene sheet (tough and hard-wearing lino alternative)
https://farm6.staticflickr.com/5804/21349135060_6a43617cf8_c.jpg
(Who needs a trailer - why small wheeled bikes win for load carrying - 4.8m offsaw battens)
https://farm1.staticflickr.com/275/19744338482_769e6f2c71_c.jpg
(Bed frame)
https://www.flickr.com/photos/h52/31379609796/in/datetaken/
(Radiator (on 90Kg capacity box trailer))
https://www.flickr.com/photos/h52/18579455896/in/datetaken/
(another (bigger) radiator plus mdf fascia boards)One issue with all trailers is the offset between the towing pivot and the contact patch of the rear tyre, and the related moments acting in the complex linkage of other weights and forces applied by the front wheel via the steering pivot and the rider. This I have learned is more pronounced when a 2-wheel trailer is towed by a bicycle and requires the facility to rotate in 3 planes, whereas a single wheel trailer only requires 2 degrees of freedom and 'leans' with the bike. The extra 'freedom means' that a 2-wheel trailer can flip over if an impulse load triggers an outward roll when cornering at any significant speed.
I still need to refine the Islabikes unit slightly to get a slight trail between the vertical pivot axis and the rear tyre contact patch, and offset the transverse pivot to stop the topple that can occur when a low speed tight turn is made when walking the bike. There is still the issue when braking hard in a turn that the unbraked trailer (weighing up to 100Kg on some trips) applies an outward force to the rear tyre causing it to slide out sideways and the bike fall away under you.
The problem is even more pronounced for those trailers that attach to a seatpost that apply the outward and lifting force with a substantially longer leverage than tow hitches mounted close to the axle and contact patch.
The best 2-axle trailer system is the 30mm tow ball (Vitelli Velobedarf for online sales) with a screw-up clamp or snap hitch , similar to the 50/60mm ball used for motor vehicles. These are normally fitted to the rear rack directly over the axle. A second option is the Miklink am axle mounted unit developed for towing cargo trailers and ambulance trailers where motor vehicle access is difficult - details from Transaid IIRC
https://www.flickr.com/photos/h52/26770886900/in/datetaken/
https://www.flickr.com/photos/h52/26441497983/in/datetaken/MIKlink hitch on ambulance trailer on Transaid stand at truck show
Whilst an overrun brake is an option, perhaps the better solution is to use the cable splitter accessories made by Clarkes, and fitted to the AM7 and related models. A neat and simple in-line sleeve and reaction cup that can be quickly separated.
I was building up a stock of such esoteria as Custom Folder, and might be persuaded to work on this ... along with all the other stuff!
The trailer also has a Mk 3 development on the stocks, a universal single wheel and hitch/swan neck which can be assembled with a basic tubular/ladder chassis to whatever length needed, or with an integral (monocoque) body.
Worst moment - riding off the Kessock Bridge downhill at over 20mph as the trailer started to hunt - as with a car (and motorbike with a tank slapper) the correction has to be by careful use of slight power and if possible weight transfer to get a better trail and enhanced self centreing. I had it once when towing a car on a trailer, where we had the engine, and weight behind the trailer axles making the nose light and tail a pendulum, the usual recipe for flipping a caravan on the motorway.
(Admin edit: Fixed your hyperlinks, though your radiator photo is possibly set to private)
Posted 7 years ago # -
The trend is growing...
https://twitter.com/GEddolls/status/1103430562801430530?s=19
Posted 5 years ago #
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