I just came across a listing on ebay offering plugs for rear fork tubes. I immediately checked mine and was amazed that ends are indeed open. I have no idea why would Brompton leave ends open as water/moisture will easily get in and result in rust. How other users look at this and did anyone close those down?
Rear fork tubes plugs
- Thread starter CEBEP
- Start date
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Darius_Jedburgh
Veteran
Interesting. Have you got a link?
here it is
Though seller posts to US only, so I can't order. And so far I couldn't find any similar products in the internet.
Darius_Jedburgh
Veteran
That will be why I couldn't find any!
I resorted to carving up a plastic cork from a wine bottle, and liberally coted the inside tubes with oily sticky stuff.
If not made by Brompton these are probably plugs from something of tubes with similar diameter (I measured 7mm). Maybe even not related to bicycles at all. I don't think anyone would create a mold and mass produce them specifically for Brompton.
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The bottom of the stays is open. You do not care about water that can pass through and droplets that can evaporate. You care about the water or moisture in general that can get trapped. You might even wonder about the plugs acting to trap the moisture after a wet bike gets its rear triangle folded and gets stored.
berlinonaut
Veteran
- Location
- Berlin Germany
If you want to harm your Brompton you should buy these. Brompton had a support document for many years regarding this. Recently they reorganized their support pages and a lot of older articles including the one in question got lost. This is what they said:
PAINT FINISH
The steel frame parts on every Brompton bike are powder-coated (rather than using a wet paint) in order to give an even and durable finish. The powder is sprayed at the frame part and attached with an electrostatic charge, it is then baked in an oven to melt and adhere it to the frame. (...)
DURABILITY
Before painting, each frame is pre-treated with a chemical anti-corrosion treatment. This protects the bare metal and prevents any surface corrosion that may develop, penetrating through the metal. Often visible in the open tube ends, this rusting is on the inside of the frame tubes and is purely cosmetic than a structural problem. The electrostatic spraying of powder paint means the powder cannot enter into the inside of tubes easily and means that there is no paint on the inside of tubes beyond the first 3-10mm. Consequently, the inside surface of the frame on a Brompton is unpainted and can appear ‘rusty’ but this will only be a surface discolouration due to the chemical anti-corrosion treatment.
As the steelwork is protected from corrosion there is no need to apply any rustproofing or similar to seal the tubes. Blocking the ends of the tube can do more harm than good and can actually trap moisture inside the frame and not allow it to breathe. Wiping with an oiled rag will lessen the appearance of this yellow-red colouration.
Original source (no longer avail): https://brompton.zendesk.com/hc/en-...-Raw-Lacquer-Flame-Lacquer-Our-Paint-Finishes
I am always baffled about the amount of people that seem to think that the people at Brompton would be complete idiots that produce a bike for 35 years w/o any thinking so that it will break within minutes and over the whole time no one recognized it whereas they themselves are so incredibly clever that they immediately, literally minutes after aquiring a Brompton (or even w/o ever having owned, ridden or sometimes seen one), identify the obvious weaknesses of the concept and know how to make it better. You should really learn that loads of people are selling snake oil. They make a living from that. Some w/o even understanding that they are selling snake oil.
rogerzilla
Legendary Member
I have known a few rear triangles rust out and break, which is why good used rear ends are quite easy to sell. I would not seal the tubes, but some Dynax S50/Dinitrol or whatever is a good idea.
berlinonaut
Veteran
- Location
- Berlin Germany
Just to get the relation:
- how long ago was that and which years were the Bromptons in question built?
- how may cases have you known and how many Bromptons do you know of where the rear triangle didn't rust through in comparison?
I'd say it probably does not harm but would not go as far to say it would be a good idea or necessary.
LittleWheelsandBig
Veteran
The rear triangle of my first B rusted out through the chainstay bridge and just about through an adjacent chainstay in under a decade. Riding on salted roads and not immediately washing the crap off tends to do that.
ExBrit
Über Member
- Location
- Southern California
PLASTIC CORK !!!!!???? You barbarian! You're one step away from canned Merlot.
They probably deleted it because it's complete BS. No powder coating is applied to the inside of the tube. It's simply not technically possible. Chemically treated against rust? I rode mine only once in the rain and rust surface inside the frame and seatpost channel appeared immediately. There is no chemical treatment to protect inside surfaces from rust.
It's arguable that putting plugs will accelerate rusting or not but leaving ends open was definitely poor design in my opinion assuming the tubes are not stainless or titanium.
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Maybe spraying rust protector inside the frame and putting plugs on both ends could offer better rust protection. Or as @rogerzilla suggested just rust protection and leave both ends open for moisture to evaporate.
What about applying WD40 periodically?
