Strengthening Folder's Rack
 

Periodically when I travel with Brompton packed folded into a suitcase or bag, I find its rear rack getting shoved into the inside of the fold, i.e. drive side. The rack pushes the fender that locks the real wheel. This is some pain when you are away from the base and lack large tools or even a piece of wood that you could afford marring in straightening the rack. After a few times like this I decided that I should do better. If you have some experiences or better solutions, I would love to hear about them.

The rack is the original Brompton rack. It has alu stays and the stays get bent in the middle, apparently when the luggage is tossed around leading to the rack's rear getting displaced to the side. I thought about replacing the rack, but the aftermarket racks notoriously look less structurally sound than the original Brompton rack. I thought about replacing the alu stays with stainless steel stays, but that would increase the weight. Finally I came up with a brace connecting the stays in the middle that should make the rack more rigid. The brace is out of a flattened alu tube and it is attached to the stays with mini hose clamps. At this point I only have one brace on the nondrive side, but I might add one on the other side depending on how the situation progresses.

https://cimg8.ibsrv.net/gimg/bikefor...6eba58bd1e.jpg

Buy one of Nittos https://www.perennialcycle.com/shopc...rack-by-nitto/

how much?
Go with titanium then..



my old Mk2 had 1 steel one , with a bottle dynamo mount on it.. of the 4.




...

Nitto rack is box-like in the rear, a floppy structure with no inherent strength. Brompton rack has triangulation by contrast. I do not to jump in to pay for an expensive lesson if I see a problem ahead right away.

Do not know, but I would also need to drill rivets, replace them presumably with bolts and cut and drill flattened tubes very accurately, most likely ending with repetitions. The brace(s) is so much simpler in comparison and potentially more effective.

Was this commercial? Your own?

[QUOTE=fietsbob;20581653]Buy one of Nittos https://www.perennialcycle.com/shopc...rack-by-nitto/QUOTE]

+1 on this. The nitto rack looks to have continuous lateral bracing in the back where as others including Brompton are compromised so that they can take less shipping space by folding.

The Brompton had a steel rack until ~1992. After that the aluminium rack was invented which then went through various iterations until today's version (which was invented in about 2016).

https://up.picr.de/33901221mm.jpg

https://up.picr.de/33901222om.jpg

https://up.picr.de/33901224kw.jpg

https://up.picr.de/33901226on.jpg

Thanks for the info and photos. The iterations indicate that Brompton does not consider the rack design to be matured either. The racks on our Bromptons are both pre-2016 but I have hard time figuring out how the current model is different. Checking the other Brompton I can see that its rack is shoved to the right too, but at this point not locking the wheel. Anticipating further work I placed an order for more mini hose clamps for the braces.

The new rack shown above does not have "pin" connected top stays so it has more resistance to "racking" sideways.

Mk2 had a rack, sold it, when I got the green M3L. w/o a rack..
fit a Carradice SQR and saddle bag on the seat post, for more space..

Rain Gear for changing weather..



...

I would not agree to this. This would basically mean any product that undergoes changes at any point in time would be immature... The changes on the Brompton aluminium rack that I am aware of are pretty subtile:

- in the early 2000s the straps were changed to the current version. Slightly different material and different designed hooks.
- at around the mid 2000s the was a second hook added at the underside of the rack. before that there was only one on each side
- in 2016 the upper flat side of the rack was changed. It offers now two lowered "rows" for the straps so they no longer stick to the surface in rolling mode. Aside of that this upper part of the rack received an overhaul designwise. The centerpart is now slightly longer towards the rear brake whereas the outer part is a bit shorter in the same area.

2016 Version
https://cimg2.ibsrv.net/gimg/bikefor...3e723c0a39.jpg

https://cimg9.ibsrv.net/gimg/bikefor...8d28c83a2e.jpg
https://cimg1.ibsrv.net/gimg/bikefor...7a8d8f8460.jpg

pre 2016 Version

https://cimg3.ibsrv.net/gimg/bikefor...68509c6060.jpg

https://cimg1.ibsrv.net/gimg/bikefor...ec63437a6d.jpg

https://cimg5.ibsrv.net/gimg/bikefor...64dfca3bd9.jpg


Hooks 2016 version

https://cimg7.ibsrv.net/gimg/bikefor...df9ff8a10e.jpg

Hooks mid 2000s - 2015 version

https://cimg6.ibsrv.net/gimg/bikefor...77cd53b6aa.jpg

Hooks ~1992 - mid 2000s version

https://cimg6.ibsrv.net/gimg/bikefor...8f6b038e48.jpg


The Brompton rack is rated for a load of 10kg - in fact it carries far more than that. You can put a child or even a lightweight grown up standing onto the rack, it will carry and you can even ride your passenger around, An unofficial way of carrying a child of primary school age on a Brompton.... Sitll bent rack stays are common - for a reason. As some other parts on the Brompton the rack acts as an protection device, in this case for the folded bike. If too much force is applied, the stays will bend. They donate themselves to protect the rear frame. Some people manage to get them bent even during folding. The tip is to catch the carrier with your foot before it hits the ground harshly - this will protect the stays from bending.
A similar protection mechanism exists with the roller wheels: The old small standard wheels rolled badly but protected the bike as the took the force, suspended a little bit and at excessive force broke before the frame did. Same with the new standard wheels since 2015 (?). Just that they roll much better and are at the same time more flexible than the old version. The easy wheels that you are using lack this protection - this may be the reason for your issues. So for airline travelers the easy wheels are not the best choice. Same goes for inline-skate wheels: Those are furthermore too heavy and too hard - longterm chances are that your rack gets bent and the little ears on the frame that carry them break.

Bromptons get shipped from the factory in a simple cardbox. 100.000s of them. Rarely something breaks. So in your case I'd assume a combination of a possilbly not too well protecting case, easy wheels and baggage handlers at the airport that cause the inconvenience. Swapping the wheels for the newer version should be quick, cheap and easy. Maybe the problem is solved then. If not I'd suggest looking at you packaging. In most cases the Brompton hard case will be an overdose but it exists for a reason. Any soft case includes the risk of underprotection when we talk about baggage handlers. Still I consider it to be better to have a bent rack stay than a broken rear frame. So your mod may in fact be counterproductive if you are unlucky.

And again the Brompton proves to be a tiny but complex beast. Purposefully designed but not always easy to understand...

Thanks for all the details - indeed this rather sounds like tweaking. The indentations in the rack for straps make sense as in my version the straps have hard time finding a space for themselves.


Obviously after you fold the bike it pushes down with a weight of 10kg :). When you are placing the bike on the ground the force is even greater.

Still, the reaction does not need to be this inelastic. A bike is generally a pretty rugged structure and the stays in the current Brompton rack are pretty feeble.

I am not happy with the roller wheels either. They are EZ-Wheels and some I bought just a month ago. All the arguments you give can be applied to a suitcase. Yet with a suitcase I can walk for blocks and for EZ-Wheels the length of a driveway is a challenge and half a block a major undertaking. After rolling the bike for half a block on EZ-Wheels they are all bruised up. I have skate wheels on order for a trial, first a pair, but after your arguments I may look into wider, but still rubber covered, aftermarket wheels.

As you go to wider EZ-Wheels you get more heel strike.

I have SideWinder on nondrive side and double crankset on drive, i.e. opportunities for a heel strike are eliminated in my situation. One way I am unfair to the EZ-Wheels is in rolling the bike mostly on 2 wheels within the SideWinder, but that also underscores my need for better wheels.

Given that far more people are interested in suitcase than in Brompton rolling wheels, I went to look what consensus might be reached there and it is skate wheels:

Best Luggage Wheels | Luggage Tips | Top-Travel-Tips.com
Understanding the Types of Luggage Wheels - Lofty Luggage

The issue then remains of weight. The Brompton EZ-Wheels weigh 32g each and 60mm skate wheels offered by Bikegang are listed at 57g. Two wheels will hit me at 50g

The thing is that skate wheels lack the dampering. No doubt the roll better than the Brompton wheels (if have skate wheels on my Bernds folder) but the main issue with rolling the brompton is rather the axle width than the wheel size. Skate wheels do not damp, so when rolling extensively may damage the "ears" through vibration alone. Let alone you problem during flight. I'd rather recommend the new standard wheels - they roll about as good (or a tiny bit better) than the former ez-wheels but offer dampering. And they are lightweight.

PS: Regarding suitcase wheels: There may be a lot to say about this. My strategy was to buy a Rimova suitcase and you are done. Best wheels I ever had on a suitcase despite being the same form factor than other ones.

My rolling wheels, that get most use, are directed laterally and are mounted on right angle alu pieces, see one on the corner of the rack in the first post. If something were to go bad, it would be the alu pieces getting the hit, so I might be OK there going with the skate wheels in your argumentation. On the other hand, along that line, I should hold on with replacing any of the remaining 3 EZ-Wheels. In suitcases indeed every once in a while a wheel goes but then they get so much more abuse than the Brompton rolling wheels.

I have luggage donts arrived at by evolution and I do not do zippered suitcases. However it is good to hear that there is something to aim at there regarding the wheels.

I think side winder loads the rack in its weak direction and puts greater forces on the struts and may weaken the connecting rivets at the tops.

I understand where you are coming from, but this has not been an issue so far for us. When we encountered a locked or nearly-locked rear wheel this was each time after a travel with the bike and in most cases before there was any SideWinder there. As to hauling around a bike on a SideWinder, the response from the current rack appeared completely elastic. I cannot tell about the long-term impact on the rivets, but the concern certainly adds to interest in strengthening the rack structure.

The SideWinder itself allows you to integrate pretty seamlessly with the rest of the population and, since I put it on, it has been my preferred way of rolling the bike. In fact if your concerns were true I would still persist in using the SideWinder or equivalent or partially equivalent contraption and, in spite of potential loading problems, either seek ways to strengthen the existing rack or switch to another rack, down to making a rack from scratch.