Large capacity aerodynamic tailboxes.

Cruzbike is missing a trick in comparison to its European counterpart the Dutch company M5 in that it doesn't make large capacity aerodynamic tailboxes that can directly fit to standard bikes with the original seats. M5 make an 88 litre tailbox that can fit to the Shockproof and now a 57 litre bag that can fit to both it and the Carbon high racer. These tailboxes can be used for commuting and touring. Thor make a 35 litre tailbox that can be fitted to a Thor seat that has bee fitted to Vedettas and German company Proceda Gmbh make large capacity tailboxes but they fit to their seats. This is too much hassle, I think a Cruzbike made or licenced series of tail boxes that directly fit to its bikes with no modification would open up a significant capability to Cruzbikes range.
Why I like these tailboxes is that they not only have a large capacity but they actually reduce drag coefficient on the bikes. So you actually go faster with the tailboxes than without. Cruzbike promote the S40 and the Q45 and T50 as commuter options with pannier racks. This is a good option as I am a big fan of pannier racks over backpacks for commuting. I currently commute on a Giant Quick-E ebike with a pannier rack bag and used to use an Ortlieb messenger bag with a Diamond frame bike, the pannier bag being far more comfortable.
On a upright bike one of the advantages of a pannier rack is that you can get into the drops or use clip on aerobars so the drag can be offset by your body position, this is important with ebikes because you are cruising at higher speed.But this is not the case with recumbents, pannier bags increase drag. Why I think there is an opportunity is that a commuter configuration with say a V20C or other recumbent with a lower drag than the original bike can compete with not just other upright recumbents but also ebikes. According to M5 an upright bike will do 32 kilometres per hour at 250 Watts and 35 kilometres per hour in the drops, 37 km/h for a time trial bike and the Carbon High Racer will do 43 km/h and 48 km/h with a tailbox. I have seen videos of a Carbon High Racer cruising at around 40 km/h without a tailbox .
If you think about the potential advantage a recumbent starts with a lower drag coefficient to an upright but as soon as you fit any storage capacity to an upright its drag coefficient goes up but the suety of aerodynamic tailboxes is that not only does a recumbent start with a lower drag coefficient but you add between 57 and 88 litres of storage and the drag coefficient goes down so the difference if even greater I commute on an ebike and that is about the speed I cruise at my ebike is limited to 45 km/h or 28 miles per hour and I cruise at around 40 km/h in good weather . This means that if that same Carbon High Racer had a tailbox at the same power output it would do around 43-44 kilometres per hour. The M5 Shockproof with an 88 litre tailbox only requires 175 Watts to sit at 40 km/h. That means that a recumbent fitted with an aerodynamic tailbox is going to be faster than any non assisted bike. On my ebike I am pretty much faster than any other bike out there.
This would be true of a Vendetta as well. Now a Vendetta is not cheap but neither are a lot of ebikes, especially fast pedelecs with a 28 mile per hour limiter. A Scott E-Silence is around the same price as a Vendetta.
The huge advantage of a recumbent over an upright ebike is that you have essentially unlimited range that can be also used in touring and don't have to deal with the issue of electronics or batteries which have to be replaced and are really expensive. I just feel that the current configurations that Cruzbike have compete well with non assisted bikes but getting them faster will enable them to compete more with ebikes
 
Last edited:

Henri

scatter brain
You are bot the first to want a tailbox for Cruzbikes. Before deciding between V20(c) and S40, I even contacted Proceda, if they see a difference in the chance to fit a box to each one.*
I have a tailbox for my Toxy Flite and I only detach it because it's in the way if folding. (It is also in the way if the stock seat mounts. Once I have a way to remove the seat without taking off the box, I will keep it attached and only ride without box, when I plan to pack the bike into a smaller car. In the train it should be okay to have two pieces of luggage with me.) Not more heavy than rack and sturdy bags.

Nice: Lots of space. Does bot sway, so the bike rides more controlled. Does not slip to the heavier side like bags that are thrown over the seat like Radical Design Bananas. No aero penalty, maybe even gain. Lockable. Rain proof. Quick and easy to open and close. Very visable and a great canvas for even more visibility and customization. Protects the luggage from impacts.
Annoying: Highly irregular shape, won't fit box-shaped objects, has no straight floor (bad for takeout food unless modified) and things in the forward "spikes" are bad to reach (maybe make side drawers or just front access hatches). Bulky (in tha garage, train or bike rack). Can get scratched. Center of mass can be quite far back and up, which is bad for front drive. Expensive. Can't easily datach and carry around (Detaching can be made more easy, but carrying even with a strap will be unwieldy. Maybe design custom bags in the shape of the box inside to take out and carry the luggage in one package). Considerred a fairing in races? (I don't care!)

*) They said, their lowracer boxes should fit both models, but I don't know if they zook into account the shape of the Cruzbike sets, that is very different with their outer rim instead of two spines. I am planning to go to a dealer and have them take a look and guess. I really want one. Maybe I will look for someone to make one custom.
 

Frito Bandito

Zen MBB Master
I have no experience in laying fiberglass or carbon fiber, and I don't have work space to do it where I currently live even if I knew how. So, I have spent an ungodly amount of hours at all kinds of shops trying to find an acceptable solution that I can modify to work on my V20. I have found several unacceptable solutions that would leave me dissatisfied in the future, so I haven't done anything to effectively solve it. I have a possible solution that doesn't require building one from scratch, but it does involve a bit of modifications that probably anyone who can operate a few basic tools can do.
 

Beano

Well-Known Member
I'm not convinced on the numbers that M5 provide regarding their power. A Shockproof with a 88 litre tailbox that can do 40kph from 175 watts?
 

Henri

scatter brain
I'm not convinced on the numbers that M5 provide regarding their power.
I think those are famously extremely optimized with unrealistic setups. Never believe manufacturer's claims. But aerodynamic drag should be lowered enough to outweigh the added weight of the box on most rides, so it's at least "free" storage. (Luggage weight will of course count extra.)
 
I made my own Carbon box. Just posting here if you decide to go that way:

 

Derek

Active Member
I bought a Brain bag from Bacchetta and it works pretty well. Plenty of room for a 3.5L bladder and room for tools, windbreaker etc. I bent an aluminum bar to support the bottom as others have posted about on here in the past. Stock seat. Attached a fidlock water bottle to the side using a fabric mount which is incredibly un-aero but still got a .209 CdA on my last 40 mile ride (a drag-tastic winter jacket and no rear disc wheel). So, I’m satisfied. That said will be ditching the side mount bottle and instead moving it under the boom. The bag is wider than my head but the way it hangs off the seat pulls the fabric backward at an angle so I think the air can flow around it without a ton of drag. For the price, I highly recommend it. I think it’s a better solution for me than the race case was. The race case would be perfect if it had a hinged top. Perhaps the new version that’s expected out later this year will.
 
Last edited:
I bought a Brain bag from Bacchetta and it works pretty well. Plenty of room for a 3.5L bladder and room for tools, windbreaker etc. I bent an aluminum bar to support the bottom as others have posted about on here in the past. Stock seat. Attached a fidlock water bottle to the side using a fabric mount which is incredibly un-aero but still got a .209 CdA on my last 40 mile ride (a drag-tastic winter jacket and no rear disc wheel). So, I’m satisfied. That said will be ditching the side mount bottle and instead moving it under the boom. The bag is wider than my head but the way it hangs off the seat pulls the fabric backward at an angle so I think the air can flow around it without a ton of drag. For the price, I highly recommend it. I think it’s a better solution for me than the race case was. The race case would be perfect if it had a hinged top. Perhaps the new version that’s expected out later this year will.
I have a Fidlock bottle too and tried it under the boom on the V20 but I can't sit up with the bottle in situ so I rotated the upper part of the boom 180º to put the bottle at the top

Could it be that my initial fit was wrong so I couldn't sit up with Fidlock bottle fitted? It's the 600ml version I think
 

Derek

Active Member
Yeah that’s pretty weird that you can’t sit up w the bottle under the boom. I have a 33oz bottle in there and it fits just fine w/o restricting my movement. My inner thighs brush the bottle sides a tiny bit but that part of my legs are covered by bike shorts anyway so shouldn’t chafe. I personally would avoid the top of the boom since it’s up in the wind.

Btw: we must have different versions of the v20 because my boom has bottle mounts under and on top of it
 
Yeah that’s pretty weird that you can’t sit up w the bottle under the boom. I have a 33oz bottle in there and it fits just fine w/o restricting my movement. My inner thighs brush the bottle sides a tiny bit but that part of my legs are covered by bike shorts anyway so shouldn’t chafe. I personally would avoid the top of the boom since it’s up in the wind.

Btw: we must have different versions of the v20 because my boom has bottle mounts under and on top of it
Definitely only has mounts on the side without the measurements... I'll have another play with it this week if the weather warms up
 

Derek

Active Member
The key if you choose to put it under the boom is to go underhand w the dominant hand to remove it and reattach it. So it’s: underhanded grab, flip it around to squeeze/drink, flip it around for underhanded reattach. It took me a few different techniques before landing on that as the best approach so I figured I’d save you the trouble.
 
The key if you choose to put it under the boom is to go underhand w the dominant hand to remove it and reattach it. So it’s: underhanded grab, flip it around to squeeze/drink, flip it around for underhanded reattach. It took me a few different techniques before landing on that as the best approach so I figured I’d save you the trouble.
It’s not accessing the bottle that’s the issue, with the bottle in situ it will hit my chest if I try to sit up.. I’ll try moving the bars toward the BB as I may have them too close
 

Derek

Active Member
It’s not accessing the bottle that’s the issue, with the bottle in situ it will hit my chest if I try to sit up.. I’ll try moving the bars toward the BB as I may have them too close
Oh wow yeah I have my handlebars as far forward as I can without hitting my knees because it makes my elbows straighter which should be more aero
 

Henri

scatter brain
PXL_20230521_161202858~3.jpg
Quite a few things to be done still, before I can do real test rides. It might wobble a bit / wag it's tail, when I shake in the front. I hope, the headset is loose, but the seat might be flexing. If so maybe I can get some sideways stiffening for it.

It's a seat and box from German manufacturer Toxy, originally for their lowracer Toxy ZR. Produced by Proceda/Novosport. By chance it fit the contournof the frame quite nice (size L). The little mounting wings in the front got a axtra set of holes for the screws and the custom rear mount is inserted where the headrest would go. Arved said, he wuold be willing to make more of the custom mounting, if interest exists. (Again: He's in northern German.) I am going to post the price and pictures of the mount in a preliminary report soonish, I hope.

(Wheels are the gravel sixspoke from Nextie, Handlebar is Corner Bar from Surly.)
 

Xrad-T50

New Member
She looks fast just seating there! How are you liking the new corner bars? I have seen a lot of you tube videos on them.
 
Top