Brompton - advice on rear fold problem after Nano conversion

[Cycleops]

At least it's good to know what the real problems are. You haven't thrown money at a dead bike, you can transfer the conversion to another Brompton if you wish or sell it.
If you do get the repairs done you'll effectively have a new bike.

 

[alicat]

He then had a look at the bike and pointed out some major problems:
rear hinge needs replacing;
main frame needs replacing as I have over-tightened the seat post (hands up) and cracked it.

Aaaaaaaaaaaggghhhh! and triple Aaaaaaaaaaaggghhhh!

 

[Blaugrana]

At least it's good to know what the real problems are. You haven't thrown money at a dead bike, you can transfer the conversion to another Brompton if you wish or sell it.
If you do get the repairs done you'll effectively have a new bike.

Thanks for the positive thoughts.

I may be feeling particularly negative but the problems remain:
I still don't know why the fold isn't working.
I don't have any confidence in the person who did my Nano conversion.
I'm not sure that I would be happy with a new Brompton with my Nano kit swapped on to it, even by a different installer. In my very brief experience there were a few 'issues' and I don't know if these could be resolved.

To get my Brompton repaired I can only use non-dealers and I don't know if non-dealers are set up to replace a main frame and rear hinge.

I'm sticking with aaaagh, but thank you.

 

[alicat]

I suspect there are a fair few people who have worked on Bromptons for yonks and are competent to do the work but have chosen not to be dealers or have been rejected by Brompton because they do unauthorised conversions.

Did the Brompton Junction chappie say why the rear hinge had failed?

 

[Blaugrana]

Thanks, alicat.

Maybe I'll go back to LBK and see if they fancy replacing frame!

I've noticed some 'play' in the rear hinge for ages, but never worried about it until visiting Brompton Junction.

I'm sure the Bavarian road network will be almost as good as their cycle network...

 

[alicat]

Bit of a long way from you in Warwickshire and he might be off travelling; however I put my trust in Graham at Tiller Cycles. He is advertising an electric Brompton so he might be classed as over on the dark side. I would have confidence in him to do the work or he might be able to recommend someone closer if he's off travelling.

 

[Blaugrana]

Thank you again.

Once the dust has settled I could make a trip that far. Nano are based Leamington Spa and was thinking of going there.

 

[ukoldschool]

I have had my 2009 M6R Brompton converted by Nano and it is now not folding right.

Part of the problem seems to lie with the rear of the bike, which *shouldnt* have been affected at all by the conversion, so I am stumped.

The rear wheel seems to be further from the frame than it should be and the seat post hits the stop and sits 4 inches higher than previously.

Any advice gratefully received, including ideas of places in London I could take it for them to have a look.

Thanks,

Jeff

Am I going mad or have you put your seat down before folding the rear wheel under, and therefore the post is catching on the frame stop. Thats whats stopping your fold.... seat down is last move on the fold.
I am sure that a competent mechanic could weld up the crack in your frame (seat post tube) then grind it back down flush to save you buying a new one, they are only mild steel.

 

[ukoldschool]

 

[Blaugrana]

Thanks, ukoldschool.

Unfortunately, the fold is not due to me folding it wrong, though I am eminently capable of having done so.

The welding idea adds another possible solution - thanks.

Alicat - I've been in touch with Graham and he is confident he can sort it all. Thanks so much for the recommendation.

Jeff

 

[alicat]

Alicat - I've been in touch with Graham and he is confident he can sort it all. Thanks so much for the recommendation.

Jeff

That's fab. He's a great bloke. You can trust him 100% and you'll be in good hands.

 

[Kell]

Is the fold not going all the way round because one of your chain stays is catching on the frame? Is the rear end that far out?

I must admit, it looks all kind of wrong to me in the picture. The tyre is what should be butting up against the seat tube (and the main frame tube when fully folded), yet yours looks like the mudguard would hit the seat tube first. They haven't fiddled with the brakes and put the mudguard on the wrong side of the brace have they?

The other possibility - however slim - is that you're not doing it in the right order. Though if it worked before the conversion, this seems unlikely.

However, for the benefit of removing all doubt, when folding you should fold the main hinges from back to front.

1. Release the rear wheel and tuck it under.
   
2. Undo the frame main hinge and swing the front end around, tucking the catch onto the drive side stay. (NB this is when the rear wheel moves into its correct position, if you put the seat down before doing this, then it won't fully fold.)
   
3. Undo the handlebar and swing this into position.
   
4. Finally, put the seat down and this locks everything in place.

If you try and put the seat down before completing everything else, you'll find that the rear wheel hasn't tucked up fully.

When putting it up, it's almost the opposite - except I start with the handlebars, then the seat post, then the main frame hinge, then the rear wheel.

This isn't my bike, but this is where the wheel should be when fully folded.

 

[Schwinnsta]

Looking at your picture, it looks like the stop disc is out too far. It also looks like your missing the rubber stop on the bottom of the seatpost.

 

[kais01]

yes the stop disc prematurely catches the seat tube. but it seems to me that a possible reason for this is that the rear wheel catches the bottom bracket before the bottom part of the main tube.

why would that be? well the wheel and tyre seem of correct size. then looking att the front part of the chainstay it seems possibly shortened; collapsed and/or repaired??

the crack in the seat tube might also alter the angle and position of the seat post, causing conflict with the stop disc.

at first i would check the front part of the chainstay.

i suspect the nano conversion per se has nothing to do with the problem.

 

[kais01]

here is a somewhat similar situation. to make room for a 10sp cassette wheel i had to widen the rear triangle. this effectivicely shortens chainstay and seatstay, results in a squeese between tyre and bb. fold is not complete, but still ok, and nowhere near the situation of our ts.

in the second photo it is easier to see the angle i made of also the seat stay; on a stock brommie it is straight.