Brompton project

[JhnBssll]

I've designed a bracket, now printing it off for the first time to see what tweaks are needed to the geometry

 

[12boy]

After you learn how very nice a Brompton is for commuting you may think again. The ability to carry a load in the front on the frame is amazing especially as that low center of gravity actually improves the handling. Keep us posted after the bike is finished and you ride it, please.

 

[Gunk]

Great project, I’m looking forward to seeing finished, have you made a decision on paint/colour?

 

[JhnBssll]

No decision on paint yet but I've got a few ideas... I'm still torn between keeping it subtle and subdued or shouty and bright

First print out of the light bracket went well - the light fits the bracket almost perfectly (which to be honest I wasn't expecting first time!) but I've got the spacing a little out on the seat stay clamp features so I have another set of bits printing now Should do the job nicely If the next set fit well I'll print a final set at a slightly better resolution

 

[JhnBssll]

I've printed an updated lower mount, it now fits perfectly to both light and seatstays With this confirmed I've started the top part printing after tweaking the 3D printer a little - this print was better than the previous ones but if it can be improved slightly for the top part I may as well try

 

[JhnBssll]

I wasnt happy with the angle or height of the light when I test fit the mount so I've made another iteration of it

This time it sits higher points almost directly back rather than dipped down as it was before...

Just need to print the bottom half of it and I can call it done

In other news the sprocket has arrived so I've fitted that to the hub and checked the chain line. It was a bit out so I've shifted the chainring to the inside of the crank spider. This is far better but the chainring is only a couple of mm from the pivot now. I'll have a play with some BB spacers to move this over a little and that should be about right I've also got a 44t ring on the way which should better suit the Alfine hub.

Next job is to get the chain tensioner mods underway

 

[JhnBssll]

One of my colleagues turned down the spacer this morning, it now fits the tensioner a treat He blasted the green paint off toowhile he was at it

I'll pop it on the bike later this evening and take some measurements to get the idler spacing sorted tomorrow

 

[12boy]

Lookin good!

 

[JhnBssll]

I managed to spare some time on the Brommie yesterday evening but forgot to post my progress. With the anti-rotation washer modified I fitted the tensioner and went about replacing the idler spacers to get the correct alignment. This ended up being relatively easy as I had some black nylon spacers in just the right size in one of my handy drawers of odds and sods

That done I popped the chain on and immediately found a problem - the upper idler back plate clashed with the spokes I've removed enough material to create some clearance and will tidy it up later.

With that done it all runs rather nicely

Next time to check the fold again...

I did come across one minor niggle that I had predicted but not fully thought through - when folded the chain touches the brake boss bolt. I'm not convinced this really matters and don't intend to change it but it'll probably bug me every time I notice it

All in all pretty good progress though!

 

[Gunk]

Looking good

 

[tom73]

 

[JhnBssll]

A few more bits have arrived so I spent an hour or so playing with the Brompton this evening

First up I whipped the bottom bracket out to fit the spacer and try to get the chain alignment right...

While the crank arm was off I replaced the chainring with the 44t hobby that arrived yesterday.

Next up was the new spring and seatclamp assembly...

It looks pretty funky, time will tell how annoying it is in the real world Rear end built back up and she now looks like this...

Getting there! So how on to the front end. New Brooks Cambrium grips (matching saddle en route) fitted and Alfine gear display fitted to the lh side.

New folding stem spring clip fitted to the forks.

And another test fold for good measure...

 

[Randomnerd]

Interesting thread. Your grips might give you a lead with paint colour. I'm thinking desert camouflage would look the business.

 

[Justinitus]

Very interesting thread this!

Does the smaller chainring solve the issue with the chain touching the brake boss?

 

[Gunk]

Just gun metal grey with Brompton decals would good, people would think that it’s a new higher spec factory bike