Category Archives: My Brompton

Ralph-e’s overdue Hack?

Ralph-e (my Alfine 11-speed Brompton – with a GrinTech electric conversion) has had a frustrating “chain drop” issue throughout the 5 years we’ve been together. With “Murphy’s Law” timing, infrequently the chain can be dislodged from the rear cog & chain tensioner sprockets. I’ve developed a second-sense feel for a successful unparking step, although I admit to including a quick look down at the chain at the rear hub before attempting to ride away. 

The following 3 pics illustrate the scenario: (1) taut chain over the rear cog, (2) slight reduction of tension in the chain (where the chain is sagging & starting to slide down & out over the widened rear frame), (3) further reduction of tension (resulting in further chain sag over the frame & commencement of the chain moving off the teeth of the cog). At this point, if the rear wheel rotates backwards then the chain will fall off the cog & then off the tensioner sprockets. The reduction in chain tension usually comes about when parking/unparking & as long as back-pedaling is minimised then chain drop can be avoided. I believe the Alfine hub also has some slight drag when rotating backwards & so vigorous back-pedaling while riding can also achieve increased chain slack & sag over the rear frame tube; hey presto, chain drop?!



Now I think I may have resolved the issue, through setting up a “chain keeper” for the section of chain closest to the rear cog (thereby maintaining chain alignment over the cog teeth). The next 2 pics show my chain keeper in situ with the chain taut (pic 1) & chain sagging (pic 2). My keeper?: a large-sized cable tie (working great). Maybe not what Brompton would do?

Advertisements

Robinson’s last ride

Tough night tonight. Had my last ride on Robinson & then Robinson took its last ride in the Tardis – to a new owner in Sydney…
As my original Brompton & source of initial education for riding, upgrades & maintenance, Robinson was greatly valued & appreciated. On behalf of Mrs Aussie & I, as well as Peregrine, Clarence & Ralph-e, we salute you. Farewell Robinson.

Monkii revival

Updated – 7/1/17 (refer end of post)

My Brompton bidon cage system is still my favourite but it doesn’t suit someone that wants to use their folded Brompton as a shopping trolley, with handle bars unfolded & a bag on the luggage block – because the cage would foul the bag & regularly removing/installing the cage is best avoided. (Whoops, see update below.) A cage that is readily removable is the Monkii system but after trying one for some time, I’m not keen on 2 aspects of the design. First, I don’t like strapping the bottle to the cage & having to remove the two together when drinking. The killer issue though, is that the Monkii cage can readily be ejected when riding over bumps. So, here’s my attempt at fixing those 2 issues…
Peregrine with the old system… 

 
… & Clarence with the new setup… 

 Here’s a pic of the old & new components… 

 
Recipe: take one Monkii system, remove the strap & cut off the wings & tail of the cage. Drill & countersink the cage spine & attach to a standard cage with some screws & nuts. When the Monkii stem block is being mounted, hook an O-ring under the block. When installing the new “combo cage” to the bike, hook the top of the cage under the O-ring & stretch it up so that the Monkii portion of the cage can be connected to the Monkii stem block. 

 
So, I now have a Monkii system that lets me easily remove/attach the bottle when drinking & won’t become disconnected over bumps – & lets me readily remove the cage when operating in “shopping trolley mode”!

Update: Since using Ralph-e & trying to avoid removing the luggage bag (& disconnecting the battery), I now realise that I can leave my Bidon in the cage system & the bag just pushes the Bidon to the side (as the bag pivots around while folding the front wheel).

2017 Best wishes

The very best of wishes for the New Year to you from the Aussie household. We’ve had a very interesting 2016 year & I’m sure that regular readers of the blog have observed the many outings & happenings of the Brompton family.

The introduction of Ralph-e reminds me that Brompton are also crafting an e-bike so maybe a good time to offer my experience & recommendations?

Accordingly, “a Plea to Mr Brompton…”

I’d like a lightweight mid-drive Pedelec Brompton with torque-sensing BB & on-bike battery storage, easily removable (aircraft-legal, 100Wh module units), but not impinging on luggage capability. I’m also happy to use my local hills for testing of various gearing options, & undertake frequent travel to review in-field scenarios not available to UK residents. (e.g. why wait to get your hot weather testing done?)

2016 Seasons greetings

Seasons greetings to all from the Aussie household – & the Brompton family…

What did the year bring? Between Mrs Aussie & I, we did the London BWC & Sydney BUC & got another Pennants badge. Pretty good BBB year I’d say? (i.e. Brompting, Blogging & Bowling)

Ralph-e extras

Tools –

Along with my Brompton toolkit (stored on-board), here’s Ralph-e’s luggage bag set of tools.
There’s a few new items that most Brompton owners wouldn’t include but you’ll probably pick them from the descriptions below.

  • Brompton toolkit
  • 17mm front wheel nut ring spanner
  • Spoke tool
  • Allen keys
  • Pocket knife/scissors for heat-shrink removal
  • Electrical & duct tapes for cable repairs
  • CO2 inflator
  • CO2 cartridge
  • Tyre levers
  • Puncture repair kit
  • Tyre pump – Topeak MiniDualG
  • SV4 tube (in addition to one in the mainframe)

Tweaks –

Knowing Ralph-e was going to become considerably heavier after the electric conversion, & probably needing good stability when folded & rolling, in preparation I moved/robbed Robinson’s rear rack (after all, the rack weight was unlikely to be noticed on Ralph-e & Robinson’s role as “spare” would just as easily be accomplished as an M6L?). This turned out to be a very worthwhile operation. However, what I hadn’t anticipated was the borderline stability when Ralph-e was folded (especially with the luggage bag fitted). With the front wheel motor & battery weight concentrated outside the center-line of a folded Brompton, great care was needed to avoid toppling when transporting, etc. Seeing a BikeFun Eazy wheel extender on a Brompton at the Urban Challenge, what I may have considered as “functional bling” now leapt into mind as “essential function”? Sure enough, BikeFun’s brilliant gadget was right at home on Ralph-e & has quickly been integrated into the Brompton fold sequence (i.e. “Left pedal down, right wheel out, park, etc…”)

Progress –

Two aspects of life with Ralph-e have been pleasing. Beforehand I’d wondered if the weight would be a concern when folding/handling/etc & I also pondered if converting my Alfine 11-speed Brompton was the thing to do? Sure I’d like less weight but I’m coping & learning more. The knack to folding the front wheel is first to anchor the bike down by putting my toes on the rack/left-side Eazy wheels & then grasp the handlebars by each grip & lift well up until the front wheel naturally pivots around under its own weight (& the same for unfolding, where the increased weight pivots the front wheel very readily). If/when I need to lift the folded bike, my right hand grasps the mainframe just behind where the front tyre is close to the frame & my left hand lightly holds the luggage bag handle for balance. (Leaving the bag on the bike saves the inconvenience of disconnecting the battery in the bag. I’ve seen systems that allow an automatic electrical disconnection through the luggage block; maybe one day but so far so good?)

My logic for converting the Alfine Brompton was somewhat guesswork. A brief test ride of a 6-speed Brompton fitted with a cadence-based pedal assist (not a torque sensing system that I was intending) showed the disadvantage of stopping pedaling to change gear; the power goes away & your next pedal action has to start the motor again. (Brompton hub gears don’t like gear changes with pedal load whereas the Alfine hub can change gears under load, allowing me to keep pedaling & just change up or down through the 11 gears as necessary.)

My medical condition necessitates low gearing on my Bromptons. 6-speed Clarence & Robinson both have 40T chainrings & Ralph-e’s Alfine 11-speed has a 44T chainring. Ralph-e has 2 gears lower than a “reduced” 44T Brompton’s lowest gear (3 lower than a standard 50T unit) & an upper gear equal to a 44T bike. Before the electric conversion, I would start changing down early at hills to minimise fatigue & maintain some momentum. Now I’m having to re-learn many riding strategies when I can ride harder in higher gears & then quickly change down as/when necessary. Ralph-e’s lowest gears are getting a lot less use & I’m constantly changing up & down through the gears. I’m also learning about the e-bike setup with a torque sensing bottom bracket (supplying power to the motor proportional to my pedaling load). For example, on a recent gradual small rise Mrs Aussie had been well ahead but I quickly caught back up when she naturally slowed on the hill. I assume that the increased pedal pressure on the hill had the torque sensor supplying more power & I was accelerating up the hill while just maintaining my cadence? (A bigger hill would have seen me increasing my effort & changing down but this time I had a “magic carpet” sensation?) Every ride is a delight, with the power feeling smooth & natural with just my pedaling – “as it used to feel but now even better?”

Another aspect of the pre-conversion conundrum was Pedelec vs Throttle. I wanted to be able to ride my bike as naturally as possible & preferred to avoid using a throttle (assuming it to lessen the natural riding experience, although the sensation of opening a throttle & enjoying a surge of power is very appealing?). As such, I liked the theory of a torque sensing pedal assist, (as compared to the straight-out cadence measuring system) & thought I could get by without combining it with a throttle. During my first days with Ralph-e & experiencing big hills, I temporarily fitted the throttle supplied with the conversion kit, to see if it was going to help. I found that it didn’t provide any more power from the motor over what pedaling was achieving (& that pedaling was essential, rather than expect to ride on throttle alone!). The throttle is now consigned to the luggage bag, just in case the TDCM bottom bracket should fail far from home?

Interestingly, my brief test rides with various throttle systems has shown quite some differences. I don’t just mean thumb-control vs twist-grip; factors such as smoothness, sensitivity & effort were all on display. Also, the ergonomics come into play when some bike setups require a throttle on the left. One aspect for me about using a throttle, is that I would be using it everywhere; I need the motor on flats as well as hills (unlike some riders who would just use a throttle to help the effort on hills). I’m kind of glad I’m not having to choose or depend on a throttle?

Ralph-e learning

My new ebike world is progressing nicely. So far, rides on Ralph-e (a recent electric conversion of my Alfine 11-speed Brompton) have totaled about 200km along mostly coastal bike paths. Mrs Aussie has laboured somewhat while I basically cruised (the reverse of our previous ride efforts for some years?). I coped with savage headwinds & stiff hills without much concern, although a certain amount of guilt nags away (for a while?).

My technicalities recipe is to take one Brompton, add a 250watt Crystalyte motor to the front wheel & mount a 20amp GrinTech controller above the rear of the front mudguard…
Fit a TDCM torque sensing bottom bracket, with a hole drilled in the bottom of the frame for the cable connection…
Mount a GrinTech Cycle Analyst computer to the handlebars & join everything together with a wiring loom…
…and finally, include a battery (in my case, an eZee Lithium-manganese 36volt 15AmpHour, i.e. 540WattHours) within a Brompton bag at the front…
The whole experience has been an illuminating & exciting learning curve, from the ride characteristics (sounds, power-off lag (especially on slow-speed maneuvers) & smooth power) to the technical data available from the computer system (up to 11 displays for ride, motor power, human power & energy data). Choosing to “go electric” was a concern for an appropriate ride experience (brilliantly answered?), a quality product (very satisfied, even considering the likelihood of an eventual Brompton ebike release?) & a deciphering of all manner of ebike jargon & implications (eg cost, weight, power & range?).

The info & stats from the computer display has provided insights & understanding for my ebike adventure. Rather than the experience of observing a series of lights representing battery level or power levels, while riding I can see the exact consumption from the battery (amphours), my output level (human watts), economy (watthours consumed from the battery per km ridden), the usual bike computer data – & other stuff I’m still getting my head around. However, determining the all-important battery range is still a work-in-progress while my economy level has been improving with re-configuring & fine-tuning for power output. So far, a range exceeding 100kms (depending on the demands of the ride?) is on the cards – although probably not on my agenda?

Brompton weight was something I could estimate pretty accurately (about 4kg?) before the conversion although battery weight was an unknown while I was unsure what battery size to use. The 540Wh unit I decided on is great for range but adds another 4kg in weight. As usual, front luggage weight on a Brompton has virtually no affect on ride handling. I’m becoming quite proficient at folding Ralph-e with the front bag in place & the folded handling has been helped with the inclusion of a rear rack.

The final word on my Brompton ebike experience to date: priceless!