Winfried

Thanks for the tip. I checked with a magnet, and it's not steel so I guess it's aluminum.

Considering that a bag hanging from the Brompton block is closer to the frame than when hanging from the Tern luggage truss, less force is applied to the baseplate so just piling two washers around each bolt could be enough to prevent excessive stress around the holes on the block.

Last step: The baseplate on the Tern is taller (about 44,6mm) and wider (15,3mm) than the one of the Brompton. Because of this, a bag will wobble a bit horizontally, so I'll carve the inside to get the block to fit better against the baseplate.

… which looks like the perfect excuse to get a Dremel mini-drill :-)

I assume some people here know about those tools: Which model + extensions would you recommend that I can also use later for other works?

Thank you.

Winfried

It only took a bit of carving with a mini-drill and the T-Bag seems to hold:


To be safe, I won't carry more than 8kg, which is between the 7kg recommended by Tern with their longer luggage truss and the 10kg recommended by Brompton on their steel-made bike.

budgee

Congrats! You did it!..
Quite well done... and the T bag metal frame does not touch the handlepost???

fietsbob

note: Being fixed to the head tube, the real issue is hitting the brake Levers as they swing over or possibly into the bag,
as you turn the wheel, for balance.

Winfried

Nope, no problem at all. The handlebar is high enough and the brake/derailleur cables don't get in the way.

Considering its luggage truss is custom-made anyway, I wish Tern had had the smarts of making its luggage socket the same size as Brompton's so that users could use either Brompton's baggage block or Tern's (Klickfix's?) luggage truss, and buy any Brompton- or Klickfix-based bags

RadicalDesign rulez (and its Roltoptas bag is even bigger than its T-Bag manufactured for Brompton).

dr3do

@bike.gang.uk

Where to get this litte adapter (https://www.bikeforums.net/attachment...4&d=1420292790) to attach the Brompton Block on a Tern?

desriantoandika

Dahon MU P8 with front carrier block and Brompton S bag





https://www.flickr.com/photos/132680.../in/datetaken/

https://www.flickr.com/photos/132680.../in/datetaken/

dika

bike.gang.uk

How about this instead, with the base designed for Tern or Dahon? You can fit brompton bag on it directly. I am more worrying about the clearance in front of it for other folders.

fietsbob

differences in bolt spacing makes making 1 for each standard Realistic for the competing bikes .

CNC CAM that should be easy enough , in that aluminum Part ..

bike.gang.uk

Yes, we are back to this project, will make two samples ... @dr3do

badmother

For Dahons? I am about to atack a B lugageblock to fit it to my Curve but would rather have a custom made one for Dahon.

fietsbob

Plastic one wont suffer Metal Fatigue , how many flexing cycles, replicating rough roads for Years of use with a Heavy front bag load,

are you testing that Aluminium one to take & not crack?

badmother

Even the Brompton luggageblock is supposed to be changed every xx kilometer. Nothing lasts forever.

fietsbob

I just occasionally re tighten the screws holding the block to the frame.

fietsbob

I Note: Dahon puts their luggage block fitting into a compatibility with Klick Fix Mounts.

bike.gang.uk

Minor adjustment required but should be OK to go, now I need to pump up the tyres ...

tds101 

Nice!!!

ismail

Wow, great job, Sir ...

Is the spare still available?
I want one please.

mainstreetexile 

Looks good! Have you tried it with a Brompton T / Touring bag?

Any eta for when they'll be available for sale or price info?

lemauve

I agree with Mainstreetexile.

I would love to buy one too!
I'm also in San Diego!!!

slickginger

Hey guys! Dead thread I know. Let me know if I should start anew.

Do you know how much of an offset is required for the stock Brompton mount to clear the Tern/Dahon headtube without grinding anything? I'm designing a prototype adapter, and would like this info so it's a completely reversible non-DIY mod. Just doing stress analysis on it now and this offset is a major driver.

Admittedly I'm mostly just doing it for myself since I'm a daily folder commuter (Tern D7i pretty much stock) and getting sick of slinging my Timbuk2 bag! I'll have to introduce myself to the forum, just found this place and I'm very impressed with the amount of conversation on here compared with the Tern forums!

badmother

If you`ve got the bike and the Brompton block why not put some clay or similar between the two and measure the casting you get? I decided to grind down a Brompton front block (the plastic) to fit on my Dahon Curve since I did not want to wait for the one from bike.gang.uk This way of grinding it down destroys the strenght in the structure but I filled the (new) holes up with hard plastic. Not sure if I would trust it for touring with a full load but for commuting I would use it.

This solution is reversible for the bike but not for the Brompton block but that one is cheap.

slickginger

Hey whatever works. I like designing stuff so this is how I am solving the problem. I'm waiting for my block to come in, otherwise I'd just be able to measure it myself. Oh well, I'll just wait . I want to retain all of the strength of the original block, just adapt it to work on Terns/Dahons.

Which bag did you end up with?

badmother

Just remember the strain on the block is going to be different when you place it further from the headtube- as you do when using a adaptor. also the strain on the bolts.

We (me and son) have had ur Bromptons for some time so using the same bags for several bikes. I have added a Brompton block to two old steel detatchable 20" bikes in the past, there is some info about it in some old threads.

https://www.flickr.com/photos/778361...posted-public/

We have two Brompton baskets with my special rolltop modification and I bought a T bag this summer. Working on a smaller bag that can be used on both ClickFix and Brompton system.

I know what it is like to wait for parts. Just recived the wrong parts for some brakes and has to start from scratch ordering new parts

slickginger

I'm actually all over the strain part of that using FEA and (once I have the required offset) real-world testing. I'm a design engineer by trade, so I fully acknowledge that point and want to make sure this thing is structurally sound. Fatigue strength is probably the biggest issue but I don't believe that Brompton themselves are actually looking at that, so I'm not too worried. We'll see!

Isn't waiting for parts the worst?! I just want to get moving... ship faster!