Do Moulton steerer tubes break?

[rogerzilla]

Many current Moultons use a spring inside the fork steerer and a bobbin to guide the stirrup up and down inside it. The bobbin is just over 22mm diameter on a TSR, which means (given that its OD is fixed at 25.4mm by the need to fit a standard headset) the steerer is not butted and the wall thickness is 1.6mm all the way down. Earlier bikes had a smaller diameter bobbin, suggesting a thicker steerer.

Most bikes have a thicker butt at the base of the steerer because this is one tube on a bike that must not break.

How safe is it? Does the suspension relieve some of the stress in the steerer, or are Moulton just winging it?

[fossala]

Mk1 forks snapped of at the crown due to poor brazing to the steerer. This was fixed with mk2 (along with the rear forks that also snapped).

I’ve made lists of problems with Moultons over the years. They aren’t great engineers it the let down many failed (in a dangerous way) to market.

Nothing rides as well as a Moulton for years but now I feel Specialized Diverge with a futureshock 2.0 had taken the lead between comfort and speed. Still, they start at £4K so still “moulton” money.

[Mick F]

Mk1 Mk2 ??
What's mine?
Bought new in March 2016.

[fossala]

F frame mk1.

I’ve already gone through what is wrong with TSR frames in the past. If someone wants I’ll dig up my list of complaints with moultons oner the years but don’t want to derail the thread.

[fossala]

Will remove on OP’s request.

I have owned a few Moultons and I think as a do it all bike they are fantastic. My pride and joy is my AM-18, it is off the road while all the salt is down but I can't wait be be riding it again in the next few months.

The downside about Moultons are three fold. First is the poor design on many models, the second is the attitude at Moulton if you do have a problem, third is the lack of OPEN discussion about these problems.

Problems I can think of from the top of my head are.

APB suspension is too low, can lead to seat tube collapsing.
Series 1 rear forks not being strong enough.
Early series 1 front forks where not brazed correctly. It is common for the steerer to detach from the forks while riding where the brass hasn't fully flowed.
Paint on new models come of if you sneeze near them.
Moulton TSRs didn't have bump stops large enough at some point (don't know years that where effected), this meant that the forks banged into the leading link plates damaging the forks. This happened to me and Moulton refused to warranty them until I threatened legal action. IMO the damage that happened to my forks and them knowing it was a design fault that could lead to sudden failuer should result in complete recall and replacement.
Stainless steel New series rusting through.
£500 stems that go rusty in a year
Faulty rear flexitor on New Series that was leant to Bicycle Quarterly and ended up with a bad review. Moulton only fixed on proviso that the owner wouldn't lend out for review again...
Rear suspension on pivot on TSR is a faulty design. Is fixed on the SST still selling the TSR.
Early AM fork where too weak so they changed the design so there wasn't any taper.
Bridgestone Moulton rear forks can break at the pivot. I guess this is because the aluminium can't take the flex.

I'll post more when I think of them.

I would 100% never buy a Moulton new and I would only buy a few models (Later AM/Series 2/MK3) second hand after I have inspected them.

[gazza_d]

Many current Moultons use a spring inside the fork steerer and a bobbin to guide the stirrup up and down inside it. The bobbin is just over 22mm diameter on a TSR, which means (given that its OD is fixed at 25.4mm by the need to fit a standard headset) the steerer is not butted and the wall thickness is 1.6mm all the way down. Earlier bikes had a smaller diameter bobbin, suggesting a thicker steerer.

Most bikes have a thicker butt at the base of the steerer because this is one tube on a bike that must not break.

How safe is it? Does the suspension relieve some of the stress in the steerer, or are Moulton just winging it?

IMO yea it's safe and the suspension absorbs and relives a lot of the stress.

It's surprising how much vibration the small wheels and high pressure tyres create, but hardly any of it is transferred to the rest of the bike.

I've broken two of the "bent wire" dynamo light brackets just from those vibrations.

Further proof that the suspension does help though is the infamous Moulton Midi from when Raleigh owned the company and design.
They removed the front suspension to save money. And had such an issue with the frames breaking where the.headtube and main tube meet that they had to make a bolt on metal brace which was staggeringly ugly.

I've ridden Moultons for about 25 years now and been a member of the owners club for most of that time and now heard of any issues with headtubes failing, other than some of the early brazing being a bit suspect and the above mentioned Midi.

[fausto99]

F frame mk1.

I’ve already gone through what is wrong with TSR frames in the past. If someone wants I’ll dig up my list of complaints with moultons oner the years but don’t want to derail the thread.

The description "F frame" is in my mind reserved for 60s Moultons. Mick F's frame is definitely not one of those. It's a TSR which I would have described as the lower cost spaceframe Moulton.

[fossala]

F frame mk1.

I’ve already gone through what is wrong with TSR frames in the past. If someone wants I’ll dig up my list of complaints with moultons oner the years but don’t want to derail the thread.

The description "F frame" is in my mind reserved for 60s Moultons. Mick F's frame is definitely not one of those. It's a TSR which I would have described as the lower cost spaceframe Moulton.

Yes, I said that was in relation to F-frames and then made a comment about me already talking to him about my issues with TSR, the bike he owns.

[531colin]

Many current Moultons use a spring inside the fork steerer and a bobbin to guide the stirrup up and down inside it. The bobbin is just over 22mm diameter on a TSR, which means (given that its OD is fixed at 25.4mm by the need to fit a standard headset) the steerer is not butted and the wall thickness is 1.6mm all the way down. Earlier bikes had a smaller diameter bobbin, suggesting a thicker steerer.

Most bikes have a thicker butt at the base of the steerer because this is one tube on a bike that must not break.

How safe is it? Does the suspension relieve some of the stress in the steerer, or are Moulton just winging it?

Small wheel & short fork = less leverage at the crown, Shirley?

[Mick F]

I've broken two of the "bent wire" dynamo light brackets just from those vibrations.

I fitted a Son dyno hub, and initially fitted the front light on the handlebars, but didn't like it there.
I fitted it up there because Brucey warned me that the Edelux light would shake itself to bits mounted on the front brake.

Any road up, I fitted it on the brake, and it's been perfect. No rattling and shaking to bits, no breakages, and perfect.
It's been there on the front brake since April 2018.

[gazza_d]

Fitting to the fork crown like that is what I have done. On my other moultons which are V brake equipped, I found and bought jtek brackets which are super strong. The wire brackets broke where they'd been bent and there was an impression from the bending process.

I've just bought a front rack for the Cone (SST really) and it was hitting the light when mounted on the brake. I've now moved the light to the rack

[simonineaston]

How safe is it?

OP - can you elaborate? All my TSRs have been safe - well, there have been exceptions... two I can think of: the time I attempted to hop up onto the kerb, cycling through Bodmin, after getting off the chuffa. I'd forgotten to tighten the QR skewer... the other time, barely remembered, was cycling home from an evening meal at The Blue Ball at Triscombe, where the landlord had plied me with single malt...

[gazza_d]

The other thing about the suspension especially on the front is that it can and does absorb hits that would probably have someone off a conventional bike.

Those tree roots that end up as organic speed bumps on cyclepaths are a classic example. Sometimes esp in poor light they are hard to spot but a Moulton will just ride over and stay relatively stable, although you will know about it.