u/edtse88

I think if you've been on this subreddit for the past month or so you've probably seen a few posts about the G line headtube splitting due to that one catastrophic incident with the orange G line or my post sharing some incidents where people had the rivnut cracking the headtube and pulling through the frame. I've also made some videos about this topic.

Anyways, my friend recently did a Brompton factory tour and sent me this picture of the G line front section of the frame:

​Also, I know this is the G line and not the new P line because the G line headtube is shorter than the new P line. What caught my eye was that there is a very noticeable reamed bearing seat on the top and bottom of the headtube. But after watching several videos of G line headset replacements, I noticed that none of them have this feature.

Exhibit A: From Woodman Components 9 months ago

https://ibb.co/LX7DVMk2

​Exhibit B: From Brompton Duo one month ago

https://ibb.co/67ztP7zv

​Exhibit C: the Orange G line with the Split headtube, also had no signs of the reaming but it was a bit mangled to tell for sure

https://ibb.co/DHY7sYMC

​I had this suspicion since my friend sent me that picture a few weeks ago and I already saw that Woodman video but finding this video from Brompton Duo confirms it for me.

So what did Brompton change and what does this mean? Well essentially, Brompton has changed the headtube stock to be a tube with a thicker internal diameter. The outside diameter is the same and the headset specifications are the same so that means they need to ream out the top and bottom of the headtube to fit the diameter of the headset parts they were already using.

This means that Brompton realized the headtube was too thin, probably because they were getting a lot of warranty repairs from the carrier block rivnuts pulling through the frame as I mentioned in a previous post.

AFAIK, Brompton has not announced this change or issued a recall and we don't know what serial number or batch will include this new headtube. IMO this is a huge disservice to existing G line users and Brompton should issue a recall for the G line.

I personally would not buy a G line until Brompton makes clear when they started with this new headtube. Even though they are brazing with the new headtubes now, we don't know when they will be put into production bikes or where they will be shipped or if there are still old stock floating around.

What do you think? Am I crazy or on to something lol

PS I will also plug a video I just made comparing the G line to my aluminium Brompnot, where I compare the headtube and what difference the material thickness has on tensile strength and yield strength. The table below might not make much sense without the context of the video but I essentially compare the load capacity of 2mm vs 3.5mm cross section of Aluminium and Steel and you can see how you can easily compensate for "weaker" aluminium with thicker material and how the Brompnot's thicker headtube is much stronger than the assumed 2mm thick G line headtube.

*edit oops I broke the image embeds when i edited the post. Links added instead :(

​

Another day, another Brooks Cambrium Accessory!

It reuses the under saddle adapter that comes with the Be Seen Lights.

Free file to download here. Needs M5x14mm bolt and M5 nut (nyloc preferred but regular nut with threadlocker also works)

If you want to buy the adapter with the hardware, you can do that here.

I've received a lot of requests to make a padded grip for the Brooks C17 saddle for more comfort when carrying so here it is!

I also made one for the Brooks B17 which honestly requires this more but the bigger metal nose and lower rails make it difficult to make as comfortable or secure.

I think I'll release the files for free on a less refined version and sell a more refined version. It's a fine balance of giving back to the community and not letting others exploit your work for their own profit.

PS the airtag hiding place works even without the grip, seems like a pretty good hiding place!

I'm not trying to fear monger but if you own a G line, you owe it to yourself to remove the front carrier block and check if there is cracking around the top bolt (make sure you reinstall with blue threadlocker and correct torque!). Especially true if you might have carried loads great than 10kg.

This example of the top bolt pulling through the frame was shared here couple months ago. And this is another example of the consequence of the thin headtube. But it's the first case that is more worrying because it seems like it could happen if you just overload your carrier block.

I bring this up now because since I made this video analyzing those two cases of the G line issue, one other person messaged me with a picture showing the same thing which they did not notice until they removed the block to replace it (they don't want me to share the image publicly).

I still think this is a poorly designed part of the G line even if you want to attribute some blame to the rider for overloading it. In the past, an overloaded front bag might break a bolt but I've never seen a frame failure.

Just got the Dakoyu Warna and the tools are quite stiff to flip out so made some thumb studs to make it easier to access.

First impression of the tool, still getting used to the toolset over my Charge + I have had for 9 years. I really like the idea of outside accessible tools but I’ll probably miss the tiny removeable bit and bigger file (especially the diamond file).

The scissors are way better and I’ll probably get more utility out of them vs the loss of the file. The extra bit set is very compact which is nice.

I might try to design a thumb stud for the scissors too but will require epoxy to attach it, we’ll see if it’s strong enough!

You can download and print them here: https://makerworld.com/en/models/2790764-dakoyu-warna-thumb-stud

I made a 3D printable insert for a 41mm seat tube quick release collar. You can download the file here: https://makerworld.com/en/models/2781627-brompton-anti-slip-seatpost-collar-41mm-meroca?from=search

Another hack is getting a 31.8 QR seat tube collar and filing the lip off but when you have a 3D printer, might as well do it the “easy” way.

Anyways I’ll probably keep this in my touring kit since it’s super annoying if your seatpost starts slipping part way through a long ride, not worth the risk of overstressing the frame by tightening the clamp.

Saw it in a G Line Facebook group, thought it's worth sharing in a more public forum. 5000 miles/ 8000km, rider is maybe 90-100kg. He noticed the crack after feeling a low tyre pressure sensation in the rear.

The bike is modded with a Rohloff hub. Not that it would cause this crack, but could be a reason Brompton rejects it for a warranty claim. He's going to try to get it warrantied anyways. He clearly loves the bike (the mileage and the Rohloff!) so hopefully Brompton do right by him!

40mm on the spec sheet but measured as 37mm on the old single wall Brompton rims.

Fits standard brakes and mudguards as well.

Also you can get TPU tubes that are wide enough, it’s just that all of mine were for skinnier tyres.

You would think that with such a niche tyre they would just do one type of casing, I don’t know why they did 60 and 120. I kinda wanted 120tpi with yellow walls but they don’t seem to do that.

I noticed Innova also do a 37mm wide slick, maybe good replacement for pricier Schwalbe One?

Anyways just a first impression, I’ll have to see how the rubber compound holds up to wear and punctures.

That flexible fruit market basket I picked up from the trash was actually the perfect flexibility to jam the other bike into.