Large capacity aerodynamic tailboxes.

[LarryOz]

I mounted this tailbox to the headrest and the seat too - did not seem to have any bouncing or vibration problems.
I really build the tailbox for the magic - but it still worked pretty good for the V20. It can carry 4- 1 liter bottles in each side. That is usually enought to ride at least 6 hours

 

[Henri]

[comment removed]

 

[Randyc3]

I mounted this tailbox to the headrest and the seat too - did not seem to have any bouncing or vibration problems.
I really build the tailbox for the magic - but it still worked pretty good for the V20. It can carry 4- 1 liter bottles in each side. That is usually enought to ride at least 6 hours
View attachment 16787

Hey Larry, just curious, what handlebars are shown here? Thanks.

 

[LarryOz]

Hey Larry, just curious, what handlebars are shown here? Thanks.

Carbon Fiber wing style

 

[Randyc3]

Thanks!

 

[FlockiBF]

I agree. I’m enjoying one of the M5 tail boxes attached to a Thor seat. I think it’ll fit well on a Cruzbike Adjustable Carbon Seat.
It sure looks fast.
View attachment 14461

What do I do with to much time on my hands ???

Design and print an aero cover for my Lezyne GPS computer. Guaranteed to shave nanoseconds off of every mile :)

forum.cruzbike.com

I bought a Carbon case from Proceda and will fix ist to my v20 as soon as it will be delivered.
I will send photos …….

 

[MaxLean]

I built this tailbox for my Magic, but it also fits on my V20 as your can see . It is not really large capacity, but I can can 2 1-liter bottles in each side, with some extra room for tools and other snacks. It has a flap on each side I can lift and oull the bottles out while riding. I can usually ride 6 hours pretty hard with 4 liters of fuel. I'm going to work on one (perhaps 3x larger that comes all the way down the bottom edge of the seat and wll probalby cover the top half of the back wheel - hoping to have it ready for the Sweden N-S ride in JulyView attachment 16647

What seat is this?

 

[LarryOz]

What seat is this?

It is the stock seat that John Morciglio built for the magic

 

[Karl42]

For my first carbon fibre project, I am building a support mount for the smaller M5 tailbox, similar to what @vosadrian has built in alu. Yesterday I made a mockup out of plywood, which seems totally functional, but quite heavy.

I made some progress on my mount for the 21l M5 Tailbag on the V20:


The mount is still a prototype made out of plywood, so that I can easily experiment with the optimal position. Once I have that, I might either make a lighter plywood version, or make it in Carbon Fiber:


I cut off some material from the lid, so that it can be mounted with hinges. I already have some carbon-kevlar hinges, but using duct tape works just as well:

 

[Frito Bandito]

That looks great Karl!

 

[Karl42]

New prototype for the tailbag mount. My previous version had the problem that it was way too heavy, and that its way of being attached to the headrest bars was too high, preventing the seat from resting on its contact points.
After reading here on this forum about using the Cateye clamps (which are also used for the new Cruzbike Race Case), I ordered a set of those and redesigned my tailbag mount accordingly. Here is the result:





This is made out of scrap 4mm-thick plywood that I found in the garage. Current weight of the mount is 186 grams without the cateye clamps. For reference, the original mounting part from M5 for their Carbon Highracer is 140g, basically a triangle made out of carbon fibre:


I considered using this original M5 part, but it doesn't really fit on the V20, as its width and angle are wrong. My new prototype is narrow enough to fit between the headrest bars, which I like more than bolting it on from underneath.

I ordered some boat varnish to make this plywood version waterproof, and then we'll see how well it works in practice. With the varnish and the clamps and screws it will probably come out at 250 grams or something, but I expect this approach to be much stronger than mounting the M5 box directly to the headrest bars, as the box is extremely thin and light (just a single layer of CF).

 

[vosadrian]

Looks great!!

Not sure if you considered a mount like what I have here: https://forum.cruzbike.com/threads/adrians-v20-tail-box.14393/

It may not be suitable for you. Not sure of the weight, but probably in similar ball park. For me it has been reliable over many thousands of kms.

 

[Karl42]

Not sure if you considered a mount like what I have here: https://forum.cruzbike.com/threads/adrians-v20-tail-box.14393/

I did see your post, of course. I don't have any experience with bending alu tubes, so my project was guided by what I had laying around in the garage in terms of materials and tools (and skill). Making a triangle out of plywood is about the cheapest and easiest approach for this, so I started with that. And if it is good enough, there is little reason to go beyond. But of course the original plan was (and still might be) to make a prototype out of plywood, and then make a final version in carbon fibre.

 

[Randyc3]

New prototype for the tailbag mount. My previous version had the problem that it was way too heavy, and that its way of being attached to the headrest bars was too high, preventing the seat from resting on its contact points.
After reading here on this forum about using the Cateye clamps (which are also used for the new Cruzbike Race Case), I ordered a set of those and redesigned my tailbag mount accordingly. Here is the result:
View attachment 17394
View attachment 17395
View attachment 17396
View attachment 17397

This is made out of scrap 4mm-thick plywood that I found in the garage. Current weight of the mount is 186 grams without the cateye clamps. For reference, the original mounting part from M5 for their Carbon Highracer is 140g, basically a triangle made out of carbon fibre:

View attachment 17393
I considered using this original M5 part, but it doesn't really fit on the V20, as its width and angle are wrong. My new prototype is narrow enough to fit between the headrest bars, which I like more than bolting it on from underneath.

I ordered some boat varnish to make this plywood version waterproof, and then we'll see how well it works in practice. With the varnish and the clamps and screws it will probably come out at 250 grams or something, but I expect this approach to be much stronger than mounting the M5 box directly to the headrest bars, as the box is extremely thin and light (just a single layer of CF).

Looks cool! My 2 cents. If you are concerned with the M5 tailbox strength, you could consider adding a 4mm strip inside to box as a fastening provision to spread the attachment load. Going beyond….epoxy it to the bottom. Unlikely it will ever fail. How did you attach the plywood sections? If you apply epoxy to them it will stop water intrusion and if you glue it together….same unlikely to fail. Great job and has given me some ideas for a next version tailbox mounting.

 

[Karl42]

How did you attach the plywood sections? If you apply epoxy to them it will stop water intrusion and if you glue it together….same unlikely to fail. Great job and has given me some ideas for a next version tailbox mounting.

The part is mounted to the V20 headrest tubes with the Cateye clamps mentioned by @Jim Parker in this thread: https://forum.cruzbike.com/threads/another-v20-v20c-rear-rack-option-the-s40-rear-rack.15455/
Those same clamps also seem to be used for the new race case.

The wood parts are glued together with wood glue, and the whole thing will be painted with boat varnish. I'll see how well that will hold up.

The connection between the box and the mount will be velcro, and possibly a screw, so that the box can be easily taken off. I don't know yet if the bike will fit in my car with the box on, and even if it does, I might not want to lay it on the side with the full weight of the bike on the box.

 

[Karl42]

This weekend I had my maiden voyage with the 21l M5 Tailbag: a 600km (372mi) Brevet in Germany.

Compared to my previous brevet setup with the Radical Banana Racer bags, the tailbox is much more aerodynamic and allows me to carry a similar amount of luggage.

Before, with side bags ands original Cruzbike Carbon Fibre Race Case:

Now, with M5 Tailbag:



I might make some more systematic comparisons by looking at average power vs. speed on similar rides, but not having the side panniers on already makes a huge difference.
For the 600km Brevet I brought a 2 litre Camelbak with water, a sleeping mat and bivy bag, rain gear, several layers of clothing, tons of food, sun screen and toiletries, tools, and a pair of light shoes for walking around at stops.
The bike does feel a bit more wobbly with so much extra weight in the rear, but overall the experience is pretty good, and I quickly got used to it. There is less wobble with a very smooth and even pedal stroke.
Having a hinged lid is so much more convenient for easy access than the screw-on top of the race case.
I still have to make some minor adjustments for silencing the drinking hose a bit more, and switching the duct-tape hinges of the lid to more permanent carbon-kevlar hinges, and adding more velcro to keep the lid closed more firmly, but I'm already quite happy with it.

The plywood mount has been sealed with multiple coats of boat varnish, so it is probably waterproof now. Final weight is 220g without the clamps. It seems very sturdy, so for now there is no need to try for a carbon fibre version of the mount. The box itself weighs 700g including the lid.

 

[Frito Bandito]

Your V20 looks really slick with the tail box Karl. Nice going on the 600km Brevet. I'd love to read about it if you are going to post about it.

I put a bit of weight in my 1st iteration tail bag and noticed that it was more wobbly as well. I tested it up to about 40kph when heavy, and it seemed to smoothen out at speed, but it would be nice to see how V20s with heavy tails handle at speeds above that. I assume it is perfectly fine, but it would be better to test it.

 

[Karl42]

A closer inspection of the plywood mount for the M5 tailbox after the long trip which included several sections of cobblestone road and other bumpy places revealed some glue seams that have come apart. I can probably change the design to address this, but maybe doing this in alu or carbon fibre would be better after all (on the other hand, this was still a prototype made out of scrap materials. Doing this again properly with plywood and glue that are rated as waterproof might be something to do).

@Mathew Fy and @Derek, could you please post some pictures of how you mounted your M5 tailboxes?

 

[Mathew Fy]

I mount mine directly to the Thor Seat.
This photo taken from inside the M5 case shows the cut-out I made to accommodate the headrest. Notice the fiberglass repair and the aluminum stiffeners where four bolts hold it secure.



Viewed from above shows the bolts going through to the front of the Thor seat. Note the aluminum stiffeners and spacer nuts.



Additional bolts hold the edges of the seat securely to the case.


When I swap things around I treat the seat/case as a single unit.