Search found 47 matches

by Red Kite
22 Sep 2021, 10:36am
Forum: Electrically assisted pedal cycles
Topic: crank vs hub power
Replies: 27
Views: 3726

Re: crank vs hub power

I've a crank-drive torque-sensing Bosch-powered hybrid, and a converted Brompton with front hub drive and only cadence sensing.

They are obviously very different to ride although that is more to do with differences in the bikes than the drive. I like and use both. As far as the drive difference is concerned, I think that is more to do with the sensing than the motor position.

The Bosch is far more natural (as distinct from better or worse) - no sense of a 'motor bike' feel, more like having stronger legs and more breath to spare. The trick to keeping rider effort low is to use the gears when gradient and headwind increase as well as upping the assistance level. The reason is simply that the motor is torque-limited and whilst it might nominally add 300% to rider-applied torque, there is a point where it can't. It's very easy when getting used to the bike just to turn up the assistance as a first response but to give more power the motor needs to spin faster when the torque is maxed out.

The cadence-only bike feels unnatural (not necessarily worse) by comparison because the power levels are much closer to being literally that - if one reduces pedalling effort to stop accelerating, the motor power continues unabated. One soon learns to stop pedalling to cut the motor and I no longer notice the 'push' effect. Again, using gears as well as higher power if one has fragile knees is the way to keep effort low.

I have no real sense, when riding, of where the motor is or its type.

It's clear that a crank drive can increase transmission wear, whereas a hub drive should in theory reduce it. On the other hand, a hub drive will stress wheel it is fitted to. I haven't had either bike long enough to experience either problem but I keep an eye on spoke tightness and chain lubrication.

The hub drive on the Brompton is geared and gives a fair amount of shove, especially considering the weedy 5.2Ah battery.

With the right technique and low enough gears perhaps either kind can be kind to bad knees, but it is obviously worth trying out the type you are contemplating before you buy if you can.
by Red Kite
18 Sep 2021, 7:10pm
Forum: On the road
Topic: Losing my nerve?
Replies: 28
Views: 1799

Re: Losing my nerve?

I rather lost my nerve when I more or less gave up cycling owing to a heart complaint. Unfortunately it can be a downward spiral if it leads to creeping along near the kerb instead of riding more assertively - I'm not sure how the psychology works but perhaps inattentive (i.e. most) drivers subconsciously feel they are being invited to pass. I started cycling more (and faster) when I got an e-bike and I have regained confidence and seem to experience fewer scares.

It's still chilling just how bad some drivers are, particularly with inappropriate use of speed.
by Red Kite
3 Sep 2021, 8:09pm
Forum: On the road
Topic: Why do short fun rides start so early?
Replies: 100
Views: 4095

Re: Why do short fun rides start so early?

mjr wrote: 3 Sep 2021, 6:57pm
1. I think it's mostly around organiser commitments, then their preference, and only rarely does anyone try to find out what works for the majority. I don't say that's wrong, just that it's that order.
I think that's right, and it's right that it's right - as volunteers, they would like to pick a time when they can do it. Also, if it's a regular commitment, they don't want to lose a whole day every time. The riders choose whether they want to go that week - the organiser has to do it every time.

I don't organise rides, but I volunteer in the community shop. I'm not really an early bird but I do 06.45-09.30 every Saturday. I choose that shift because a shift that stopped me having other options every Saturday, such as visiting the grandchildren 60 miles away, just wouldn't be one I would commit to.

2. the opening post asked why, rather than criticised. (A few posts later, one suggested reason was called "fussy", which might possibly be seen as criticism, but that's very tame compared to what some on here post!)
Yes I noted that, fair question from the OP. Although it's surprising how many [other] folk will actually complain about something offered voluntarily when they volunteer for nothing themselves. Again the village shop provides an example - I asked a neighbour why she didn't support it. She said "it's never open. If they want people to use it they should open at least 7 'til 7." It takes 40 volunteers to run and open this shop 8am-2pm daily, and she thinks someone should be there until 7pm every day for no pay so she can go when she feels like it!
by Red Kite
21 Aug 2021, 10:35pm
Forum: Electrically assisted pedal cycles
Topic: Swytch kit on a Brompton
Replies: 37
Views: 6678

Re: Swytch kit on a Brompton

Thanks. There probably aren't too many motors that will fit the Brompton fork. Isn't the Nano the one with near---silent friction rollers instead of toothed cogs in the gear train? The Swytch motor probably isn't noisy but it certainly makes a noticeable gear whine. Although I think it's actually quietened down a bit after it's little run, unless I've got used to it already.

The wheel is hanging together anyway!
by Red Kite
20 Aug 2021, 11:19pm
Forum: Electrically assisted pedal cycles
Topic: Swytch kit on a Brompton
Replies: 37
Views: 6678

Re: Swytch kit on a Brompton

My Brompton Swytch kit came about 10 days ago, 4 months from ordering, and I finally got around to fitting it today. How anyone can do it in 30 minutes beats me, I took 3 hours including changing the tyre over and figuring out which of a selection of parts to use, where exactly to position everything, and generally taking my time. I suppose I could do one in 30 minutes now, bar the tyre change.

It worked properly first time, so at least I got it right. Darkness falling, I gave it a 5 minute test. As expected, with only a crank sensor and no torque sensing it's much cruder than my Bosch-powered Cube. Once the pedals are turning, it applies the selected level of power which is a little disconcerting when it continues to accelerate even after reducing pedal effort, but I know I'll get used to that.

What is weird is that the wheel has only radial spokes, 28 of them. I asked my engineer daughter how she would go about calculating the forces when rotational force is transferred from hub to rim. The answer I received was "no idea". It feels solid but how long will it last? The instructions advise regular checking of spoke tightness.

Edit - I've now given it a run, 7-8 miles including a short steep hill, and I'm getting used to it easily. I used power level 2/5 which helped me up the steep stretch in bottom gear which is fine for me. I still find the constant power a little odd, and frankly when I want to bimble I end up going too fast, which I then have to regulate with periods of not pedalling so as to cut the motor power. I'll experiment with varying the power level instead. Battery level has dropped by one blob.

Overall I am happy with it so far.

Image
by Red Kite
23 Jul 2021, 7:37am
Forum: Does anyone know … ?
Topic: Child's First Bike
Replies: 19
Views: 1294

Re: Child's First Bike

Good choice, cycle-wise and financially. My granddaughters are working through Islabikes now, the 6 year old is on a 20" and it's incredibly light. Daughter buys them second hand and the "depreciation", if there is any, is less than the cost of buying cheap bikes.
by Red Kite
27 Jun 2021, 11:01am
Forum: Does anyone know … ?
Topic: Breaking force
Replies: 65
Views: 3472

Re: Breaking force

The force starts with the 'grip' the force at the brake lever. Then it's mainly a question of mechanical advantage. That can be limited by travel required at the brake end and available at the lever end.

Thinking aloud, the pads in a disc brake don't have to travel very far at all so it is possible to design for a relatively high mechanical advantage for a short lever travel - easier than with typical rim brakes where more clearance is probably needed. I think it's probably easier to design for higher brake force with discs, whether it's needed might depend on the friction material.

Actual braking effectiveness (deceleration force) other things being equal is proportionate to the friction coefficient and the force. Pressure, in simple theory for a single condition, doesn't come into it. In practice, an adequate brake contact area is necessary to keep temperatures manageable and give consistency.

This is musing, not knowledge.
by Red Kite
15 Jun 2021, 11:54am
Forum: Family Cycling
Topic: 11yo grandson finally manages to ride
Replies: 9
Views: 5620

Re: 11yo grandson finally manages to ride

It's ridiculously hard to learn to speak but most people manage it. The technique is the same, practice, but children have to want to do it. Sometimes we just have to wait until they're ready. Yes, show him you have confidence but don't push would be my approach. One day, probably very soon if he hasn't already, he'll just decide he's doing it and it will take him 10 minutes.

I wonder if taking the pedals off temporarily, letting him trail his legs and pushing himself off, will help with the starting off? (balance bike style, which he should manage as he can balance).

I honestly can't remember when or how I learnt to ride a bike. My granddaughters, with cycling parents, learnt quickly on balance balance bikes which I don't remember existing until a few years ago. Predictably, the pedalling was another hurdle, balance bikes having no pedals. The (tall) 6 year old is already on a 20" bike. The younger, 4.1/2 yrs, is a confident pedaller, steerer and braker. Her ability is very high, but her confidence is higher which leads to a lot of heart-in-mouth moments. Recently she sped ahead when we were out for a walk, she on her bike. I shouted in panic "Stop at the crossing!!!!" She braked to a halt at the kerb, pressed the button on the pelican, turned to me and said, sounding just like her mother, "Grandad, can we cross the road when the cars are coming? I don't think so!".
by Red Kite
5 Jun 2021, 4:57pm
Forum: Does anyone know … ?
Topic: Selle Italia Mitica Leather Saddle
Replies: 38
Views: 7389

Re: Selle Italia Mitica Leather Saddle - Epoca

Nessie23 wrote: 30 May 2021, 12:17pm Been for 2 x 1-hour rides on new saddle and very impressed.

After first ride the tensioning screw required 3/4 turn to take up the slack which confirms to me that the breaking in process has started. No adjustment required on 2nd ride.
I don't think my new Epoca, which arrived this morning, had any tension on it when it came - not obvious because the new leather is so stiff anyway. If you get one, just be aware that it probably isn't pre-tensioned - which I suppose makes sense as it could be in stock somewhere for some time before being used.

After an initial application of Mr Jojo I went for a ride which didn't raise any immediate problem - I could feel a bit of give almost straight away, so I returned after only 5 miles or so and set about taking up any slack.

Without any stretch at all it there wasn't room to get the little spanner on to the nut, and when I turned the hex screw both the screw and nut went round together so I fetched a normal open ended spanner that just held it. It took 3 full turns on the screw with no resistance before starting to tighten up so I gave it another one for luck and I'll check it when I've had another ride out.

I like it, I'm not feeling any discomfort and It's easier to fidget than it was on the shorter, narrower padded saddle I took off.

It certainly looks good.

Image
by Red Kite
31 May 2021, 8:00am
Forum: Does anyone know … ?
Topic: Selle Italia Mitica Leather Saddle
Replies: 38
Views: 7389

Re: Selle Italia Mitica Leather Saddle

Nessie23 wrote: 28 May 2021, 2:46pm Thanks, I am now aware that Proofide is recommended by Brooks. The only instruction from Selle was “Apply saddle treatment before your new saddle is exposed to rain or strong sunlight.” The actual instructions are visible on the label in the pic above.
Warning: This may offend the Brooks traditionalists...... but i have applied an application of dubbin last night. I rubbed it in and left it overnight and was just about to polish it off and go for first ride but the heavens have just opened and scuppered that plan!
I've decided I'll try one of these - I need a slightly wider, more sitty uppy saddle than the one supplied on my Cube. I haven't had a Brooks since the one on the bike my dad built for me about 54 years ago. I wasn't aware that I was very happy with it for several years, I just never noticed it so it must have been good!

I'll try Urad Mr JoJo on the 'leather'. I've been using it for years on boots, shoes, leather furniture, even steering wheels. It's a bit sweeter smelling and cleaner than dubbin.

http://www.uradleathercare.co.uk/All-UR ... duct_id=66

EDIT - finally got my Yorkshire head around parting with £54 (how much?!) and ordered a 'honey' Epoca.
https://www.planetx.co.uk/i/q/SASIEP/se ... oca-saddle.
I can't thoil a Brooks and rumour has it that the leather isn't what it used to be in any case. High hopes for the Epoca.
by Red Kite
30 May 2021, 8:45pm
Forum: Does anyone know … ?
Topic: Where are all the cassettes?
Replies: 62
Views: 4583

Re: Where are all the cassettes?

I have just attempted to panic-buy a 9 speed 11-36 on the strength of of this and found they were out of stock where reasonably priced, so I've panic-ordered one instead:)
by Red Kite
26 May 2021, 8:08pm
Forum: Bikes & Bits – Technical section
Topic: How tight is 15Nm without tools to find out?
Replies: 70
Views: 12531

Re: How tight is 15Nm without tools to find out?

Tangled Metal wrote: 25 May 2021, 10:00am Brompton recommend 15Nm for the 5mm hex bolt on the saddle adjustment. I do not have the means to gauge this so how can you guess?

Do you just tighten until it won't go any more? Little or a lot of force? Does it matter? Better to have less tight or as tight as possible?
15Nm is 1.5Kg force on the end of a 1 metre bar. If you are gripping your hex key at say 100mm from the screw, you'll need 15Kg force (10 x the force at 1/10th of the distance). Do you know what 15Kg (33lb) force feels like? I'd say if you were using a short hex key like that it's properly tight - not "all your strength" tight, but well beyond what's needed to clamp say your brake lever to your handle bar.

I think you can feel things like this and get it right although I would use a torque wrench if I had one handy. If not, you don't have to do it in one hit. I'd tighten it a bit less than I think it would need and then see if I could move the saddle, and work up from there. Once I'd got by degrees to the point where I couldn't move the saddle I'd give it a good tweak.

IME the thing to watch out for thereabouts on the Brompton is the chrome seat post slipping down in the plastic sleeve. It's on a QR of course but if it gets a bit of oil or Mr Sheen on it, it can be hard to clamp it. I clean it with isopropanol which seems to sort it out.
by Red Kite
26 May 2021, 9:01am
Forum: On the road
Topic: Deliberate Close Passing /Assault and now just too scared to ride to work.
Replies: 61
Views: 8037

Re: Deliberate Close Passing /Assault and now just too scared to ride to work.

TallestTim wrote: 25 May 2021, 1:30pm Yes, which is why I'm often screamed at for "riding in the centre of the road" (obviously meaning lane) followed up with "you're not a car", and assaulted for it.
:roll:
It's appalling that you can be persecuted like that. I assume that is just this particular sociopath. Is there likely to be any progress with your complaint to the police? Frankly a spell at HM's pleasure wouldn't be disproportionate for what you have described.

As a driver, I like to see a cyclist riding primary. It clarifies the situation, we can both relax until he or she reaches a suitable overtaking spot. As a cyclist, I think it has become easier to take the lane over the last few years. Presumably some drivers (who may also be cyclists) have now become aware of why cyclists do it, and others have at least got used to it.

I don't know the answer to dealing with the minority that either hates cycles cyclists, or the simply ignorant, but I hope in this case something can be done.
by Red Kite
25 May 2021, 12:00pm
Forum: Electrically assisted pedal cycles
Topic: battery query.
Replies: 6
Views: 2159

Re: battery query.

jags wrote: 24 May 2021, 11:48pm will any 250watt battery drive 250watt hub motor ?
What matters is the voltage and the current it can supply. A 12V. A 12V 500Wh battery such as the one in many cars wouldn't be much use even if it didn't weigh 15Kg..

A typical e-bike battery now is 36V nominal. It needs to be able to supply up to a reasonable current (I'd guess on a scale of 10A) without too much voltage drop.
by Red Kite
25 May 2021, 9:39am
Forum: Electrically assisted pedal cycles
Topic: Ebikes v e-scooters
Replies: 33
Views: 4322

Re: Ebikes v e-scooters

PH wrote: 25 May 2021, 8:55amAre you surprised by it? IMO it's like comparing the price of apples and oranges.
Quite. You can buy an e-bike for less than Boris Johnson spends on a roll of wallpaper, so e-bikes must be cheap.