Yet Another Cycling Forum
General Category => Freewheeling => The Dark Side => Topic started by: fd3 on 11 May, 2019, 12:18:32 pm
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I have been musing about removing the rack from my speedmachine and installing something akin to a saddle bag. Some googling found the radical rear bags - but at £100 I started wondering whether I might as well buy a tail box at "only" twice the price (... until I ended up looking at the large lowracer CF ones, which are things of beauty but also about £600+).
Further googling brought me back here, to a post from 2008
https://yacf.co.uk/forum/index.php?topic=12431.0
And I am giving serious consideration to making my own tailbox out of correx. So my questions are:
Anything new I should consider, anything changed in the last 11 years?
Is this something within the realms of possibility for someone with basic DIY skillz (I can assemble IKEA furniture, but wouldn't make my own from bits of wood).
Where do you get correx from?
My starting plan is to emulate box 1 from here
http://www.recumbents.com/wisil/tailbox/barracudatailbox.htm#Tailbox%20version%203
Not looking for a massive areo boost, just someplace to store some basic repair tools, innertube and mini pump.
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I am still considering building a tailbox for the Wincheetah (see 'Tales from the Wobbly Workshop' thread if you are unfamiliar with my builds).
I have worked with composites - moulding a new seat, mainly, and did consider paper mache over a large balloon to form a shape to mould a tailbox (cutting and adding flat panels where required).
At work (School D & T workshop) one of the A level students has been working on a transport case for fencing (wiv swords) equipment, and has layed carbon fibre over a material I hadn't seen before - a honeycomb plastic sheet with a slight fleece outer layer, which gives excellent adhesion for the resin. The thinner sheets curve 2 dimensionally quite well, like plywood. I have saved offcuts so I could attempt a faceted tailbox, or even use it for the flat sections on the balloon mould idea (although I have some carbon fibre coated Nomex offcuts I intended using). :smug:
I don't know the name of the honeycomb sheet material, but apparently it was ecconomical (£15ish for a 8' x 4' sheet), but the delivery from Sheffield was expensive. >:(
We are working with Correx on the currently featured 'Wobbly Workshop' project but that's only for an artistic outer shell. The correx we will use, is from recycled A1 size Art portfolio cases :D
In my 'reclaimed' store I also have some PVC foam board that was being used as trim in part of the school - I think it is also used for signs. It is heat formable - used with the sort of hot wire/element setup for bending acrylic. It is much stronger than correx and still relatively light, so might also be a material to look out for. Maybe ask for offcuts from companies that do signs/promotional displays. ;)
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Aerolam.
Light, exceedingly strong - but it cannot be formed.
You can only fabricate rectilinear forms from it.
We used to use it (to save weight over mdf) for baseplates for large (3m x 3m) architectural models which had to be shipped to the Middle East.
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I built a correx mailbox for my speed machine for racing with the BHP back in the day - won at the last event in East London before the Olympics!
It is certainly doable, stitched with cable ties and sealed with black tape. It has a big speed improvement effect - at higher speeds/downhill. It is a temporary sort of thing though - and mine disintegrated on a hot day because the correx softened I think.
The most challenging part is creating an effective lighweight frame and mounts - I used aluminium struts and I can'r remember how I bracketed them to the frame. Bear in mind the rear suspension means the box is either attached to the seat or the luggage rack but not both!
Others have had good results with something called 'Zotefoam'.
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Bear in mind the rear suspension means the box is either attached to the seat or the luggage rack but not both!
Good to know, as I did wonder whether I would have to keep the rack anyway.
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There's a special flavour of hot glue that's designed to stick polypropylene, which is just the thing for bodging correx. Cable-ties work best if you use them across the grain (if you have to use them along the grain, stick another layer of correx underneath in the other orientation).
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Bear in mind the rear suspension means the box is either attached to the seat or the luggage rack but not both!
Good to know, as I did wonder whether I would have to keep the rack anyway.
Under no circumstances remove the rack. It is an integral part of the bikes structure and the main pin that it pivots on is a big deal. I seem to recall I mounted onto the rack, which seems the obvious way to go. The other counterintuitive thing is that the most effective box is about twice as big as one initially thinks it should be! Good luck.
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Under no circumstances remove the rack. It is an integral part of the bikes structure and the main pin that it pivots on is a big deal.
Really? That's a surprise as there are pictures of Speedmachines without a rack - in fact most of the pictures on bikefix
https://www.bikefix.co.uk/speedmachine
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Under no circumstances remove the rack. It is an integral part of the bikes structure and the main pin that it pivots on is a big deal.
Really? That's a surprise as there are pictures of Speedmachines without a rack - in fact most of the pictures on bikefix
https://www.bikefix.co.uk/speedmachine
If it's like the Streetmachine, then there are probably extra spacers fitted in the absence of a rack.
Also (DAHIKT) if you do have to remove it (eg. to replace a rack that's b0rked), that pivot is a complete bastard to reassemble, requiring that the folding-in-on-itself bike be supported while ham-fisted monkey force is applied to align the components and a third monkey tightens the bolts.
Anyway, the rack is surely an ideal structure for building a tailbox around, particularly if you want it to be easily removable.
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Stuart at Bikefix told me in no uncertain terms not to do it, as it woudl lead to me bringing the bits to him to sort out.
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Fair warning!
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Stuart has opinions about lots of things.
You might also consider foam mats, hot glued with Correx stiffening in strategic places. It depends if your priority is aerodynamics or storage or weight. Here's one I made earlier (and I think have posted earlier). It was limited mainly by the amount of Correx I had to spare, and the length of the mats I was using. It might not have added very much in the way of top speed, but it didn't make the bike any slower either.
(https://live.staticflickr.com/4158/33663704093_d3cd811c77_z.jpg) (https://flic.kr/p/ThKhpg)
Tailbox clever (https://flic.kr/p/ThKhpg) by beqi (https://www.flickr.com/photos/beqi/), on Flickr
(https://live.staticflickr.com/4170/33663707693_957beea9f0_z.jpg) (https://flic.kr/p/ThKitk)
Let's Kamm together (https://flic.kr/p/ThKitk) by beqi (https://www.flickr.com/photos/beqi/), on Flickr
(https://live.staticflickr.com/4194/34538691395_fa84e3e9b2_z.jpg) (https://flic.kr/p/UC4PDe)
Uneasy rider (https://flic.kr/p/UC4PDe) by beqi (https://www.flickr.com/photos/beqi/), on Flickr
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interested in your chain line there, do you find the return chain rubbing on the fork leg at all?
I'm running with a high front idler as well and a longer chain tube on the bottom - to just past the fork
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Probably nothing a bit of helicopter tape won't fix.
(High idler and chain tube for me too. It keeps the oil off my leg, mostly.)
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interested in your chain line there, do you find the return chain rubbing on the fork leg at all?
Yes, sometimes, but the carbon fork came with a big chunk of heatshrink tubing over it.
A chain that is dropped to that extent, running past a 700c front wheel, is an horrendous liability until you are on the open road. Turning right at T-junctions and small roundabouts, and probably hairpins on race tracks, were activities that make my Quest look manoeuverable. The bike was ridiculously quick but I'm quite glad I don't have it anymore!
The dropped chain serves mainly to prevent the inside of one's thigh being chewed through by constant rubbing on a second idler. My knees run quite close together when I pedal, and I never found a solution to the barrel adjuster on the front brake being in just the wrong place.
In terms of carrying stuff, the tailbag was for the most part a surprising success, and its weight a kilo maybe, probably rather less; basically three or four small, thin yoga mats' worth, plus three square feet of Correx, plus half a dozen glue sticks. The two sides at the top I made overlap, with a full length bit of Velcro to keep it shut, if not rainproof.
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A chain that is dropped to that extent, running past a 700c front wheel, is an horrendous liability until you are on the open road.
Whu?
*scales up mental image of bike to Arellcat-size*
Ah. (That explains the tiny handlebars.)
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interested in your chain line there, do you find the return chain rubbing on the fork leg at all?
Yes, sometimes, but the carbon fork came with a big chunk of heatshrink tubing over it.
A chain that is dropped to that extent, running past a 700c front wheel, is an horrendous liability until you are on the open road. Turning right at T-junctions and small roundabouts, and probably hairpins on race tracks, were activities that make my Quest look manoeuverable. The bike was ridiculously quick but I'm quite glad I don't have it anymore!
The dropped chain serves mainly to prevent the inside of one's thigh being chewed through by constant rubbing on a second idler. My knees run quite close together when I pedal...
that explains something, a flexible plastic tube, never installed anywhere, must be the heatshrink.
I manufactured an idler cover for the top idler to stop it eating my right knee, with chain tube to cover it. you are right about the slow maneuvering, even with a 26" front I get occasional clashes
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Well, I am such a div!
The simplest solution to my problem - toe strap round the neck of the headrest, attach saddlebag to that, job done.
Won't give me an aero advantage but a simple saddle pouch is in the shadow of the seat so won't be an issue either.
I'm still a bit incredulous that the rack would be such a faff to remove. Surely knowing that it needs to be treated carefully would solve the issue. (Yeah, I'm not certain enough to give it a go though).