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by james-o
22 Jul 2020, 7:02pm
Forum: Bikes & Bits – Technical section
Topic: Maybe steel isn't so real.....
Replies: 153
Views: 6435

Re: Maybe steel isn't so real.....

Had a test run on a Genesis equilibrium disc which is as near in spec to the pinnacle Arkose R2 I ended up buying as it's possible to get. The Genesis was steel and twice the price of the aluminium pinnacle but I preferred the pinnacle with it's internal cable routing (even down the chain stays ) . The ride comfort was very similar, in fact I would say if anything the pinnacle was better and a slightly lighter bike.


I'd agree ; ) but the steel bike has a more premium image, sells at a higher price and it's all materials history/rep/sales value. The Equilibrium is quite a stiff steel bike, but not as stiff as many Al and carbon bikes on the market at the time it was conceived. The Arkose, in particular the new frame R and D series, I'd say is a fairly flexible and forgiving Al frame. Not quite as stiff as an Equilibrium overall imo/ime and argualbly more comfortable (for ref I designed the V1 and V2 Equilbriums for Genesis and the Arkose range for Pinnacle/Evans so I know them well. I still own and ride a 2011-12 Equilibrium with the 520 tubes).

And on that note, reading the debate on planing here with interest - I had a custom classic audax style bike made recently, partly to test out how I get on with slimmer steel tubes for longer rides. Standard OS 8-5-8 tubes, 31.8 DT and 28.6 TT, a more flexible tubeset than I'm used to for a road bike. I'm a relatively strong rider but no Cat 1 sprinter. I enjoy the feeling of climbing in bigger gears out of the saddle, similarly enjoy riding my SS MTB. But I'm more of a steady distance rider generally so the BQ ideas interest me. The main thing I've noticed with this new slimmer-tubed Reynolds frame? I climb for long-ish periods out of the saddle with a low cadence/in larger gears with less leg burn than I'm used to or would think of as normal. It feels more natural on this bike. I'm not going to get scientific about it but I've been climbing that way on this new bike a lot simply as I'm finding it rewarding and complimentary to my riding style.
There is something in the BB flex/sway that feels 'right' when climbing like this. It's not the same as the oval ring I use on my SS but there is a similar smoothing effect of sorts. There's perhaps a small gain in efficiency of effort or output, or maybe it's purely enjoying the springy feel. But getting up a hill at my normal cadence and gear but feeling a little less stressed by it all is interesting. I've read about planing and gone back to it recently, I remembered that they claim a speed gain but not the lowered leg burn (can you have both? I don't think so). While I have a lot of respect for Jan Haine and his work, I can't see that planing is any more than biomechanics that work for some people some of the time. Perhaps it works for me some of the time. Not sure yet, though I can see where the concept comes from now.
by james-o
8 Jul 2020, 1:28pm
Forum: Bikes & Bits – Technical section
Topic: Maybe steel isn't so real.....
Replies: 153
Views: 6435

Re: Maybe steel isn't so real.....

Interesting OP and skim-read thread. This general point has come up in conversation a few times and one point I'd make is - yes, actual vertical compliance is within millimetres or less between frames. But what we feel as comfort in a bike mostly isn't coming from vertical compliance in the frame, it's coming from lateral twist. "Steel is real" is about lateral twist and spring ime/imo. Mostly in the front triangle.
Pedaling, steering/cornering loads and bumps that aren't entirely vertical, all twist a frame and that changes how inputs the come through the front wheel first come through to the saddle. A slim steel tubed eg lug 531 frame and a carbon race bike can feel similar vertically over small bumps when you try to isolate what you're feeling through the saddle only, but when riding normally at pace along an average UK lane or road there can be a big difference in overall feel and 'comfort'. The steel bike (thinking of a slimmer-tubed and more traditional road bike here) tends to have more lateral twist and spring / flex. My experience on more trad frame bikes is that once you unlearn the riding style that gets the best from a stiffer race style bike, a slim steel, trad square frame can be equally fast as well as feeling more comfortable because less of the lateral forces come through to the rider. Too flexible can be more difficult to hold a line around a bumpy corner or can get a speed wobble. Too stiff can also take that same bumpy corner badly. Pros and cons to all that, depends on how you ride. For me the right level of spring and stiffness is that hallowed ride feel that can be so engaging on fast twisty roads or when off road.

I think the history of the Genesis Croix de Fer is similar; originally designed as a cyclecross bike but never really competitive, so evolved into a more allrounder.

Pretty much. Originally designed as a CX bike for riders who explored more than raced as it used discs that were heavy and less/not popular for racing at the time, great for winter lanes and byways though. Also an example of a fairly stiff steel bike. It was built tough and for more -will say 'spirited' as I think 'aggressive riding' is a daft term- and for carrying a load so the tubeset was stiffer than I'd want for something like an Audax bike now. It was a 31.8 TT and 34.9 DT, 8-5-8 and 9-6-9. For me that sort of tubeset has some lateral spring if I push it harder but for more easy-going riding pace, unloaded, it'd feel quite stiff.
by james-o
8 Jul 2020, 1:02pm
Forum: Bikes & Bits – Technical section
Topic: USB outputs, USB-Werk and fault diagnosis - I'm stuck
Replies: 5
Views: 379

Re: USB outputs, USB-Werk and fault diagnosis - I'm stuck

Thanks for the input. I've got hold of a USB charge multimeter so will ride with that lined in and see what V and mAh out readings each unit gives me. The functioning unit is 6 years old and has had a lot of use w/o issues to I've not lost faith with the item itself, just interested to find what's gone wrong with the other.

Greystoke - I have one of those car chargers somewhere, might try that out. Would be interesting to see what sort of reading it gives with the USB multimeter vs the USB-Werk.
by james-o
1 Jul 2020, 4:25pm
Forum: Bikes & Bits – Technical section
Topic: USB outputs, USB-Werk and fault diagnosis - I'm stuck
Replies: 5
Views: 379

USB outputs, USB-Werk and fault diagnosis - I'm stuck

Difficult to do this remotely I'm sure, but through a process of elimination with 1 fully functional dynamo to USB-Werk system on one bike and 1 non-functioning replica system on another I wonder if the points below show something I'm missing. I have a multimeter but my electronics ability is basic, up to wiring dynamos but not fault finding like this. Much gratitude and debt to anyone who can get me further on than what I've done so far...

1) Bike A works. USB-Werk charges phone and Garmin as normal.
Bike B, the new one inc a new SON hub, didn't charge anything yesterday on a test ride. The F+R lights work as normal though. So I turned the lights off and rode ~2hrs today, more than enough to charge the cache battery in the USB-Werk so it can let charge through to devices (if it was in fact flat to start with - not sure). Nothing coming through when I tried it at the end of the ride though.

2) Checked all bike B connections with the meter. No broken wires. Power can go from hub to USB-Werk power in cable ends.
3) Swapped out bike B's USB-Werk power out USB line only with the one from bike A. Nothing.
4) Swapped the Garmin lead from bike A onto bike B. Bike B now has all the power-out side cabling from Bike A. Still nothing.
5) Checked the USB-Werks themselves, unplugged on the bench. Both are reading 5V power out on the meter (Bike A, 5.01V. Bike B, 5.5V ... is that significant? Unsure)- so there must be charge in the cache battery to get that reading, right? - this corresponds to there being no dynamo resistance on bike B with USB-Werk lined in when the wheel is spun, since I think it's topped up and is not drawing power.

- but if the cache battery of bike B is full and reading 5V+ out, with all functional leads attached why would there be nothing going into either a phone or Garmin plugged into it?
- If I swap over only the USB-Werk itself, bike B works fine. So tempted to say I have a duff USB-Werk.. yet it reads 5V+ on the meter?

Is this about Amps as well as Volts? Both USB-Werks read 0.05 microamps when unplugged, I suppose there's no current pushed through from the dynamo, but it's hard to spin the wheels and measure the output (should be 0.5A).

Stumped. Any ideas or hints of what to try? Thanks.
by james-o
7 Aug 2016, 9:19am
Forum: Bikes & Bits – Technical section
Topic: What is the "centre of steering"?
Replies: 34
Views: 2079

Re: What is the "centre of steering"?

One of Thorn's great admonitions against short stems is that they might put the rider's hands behind the "centre of steering" thus causing an uncontrollable wobble or shimmy.


Only if the bike is inclined to shimmy in the first place. Colin's points are right re shimmy, I'd say. It's a resonance related to the spring or stiffness of the frame and the front end trail, and speed. Tyres, pressure etc can influence it too as part of the trail 'system'. Resonance can occur and where your hands are may be part of resisting/preventing/controlling it but not a cause. Hand position can affect weight distribution and that's part of it, but again only if the bike can be prone to shimmy.

Hands behind the steerer tube -as I assume they mean by centre of steering?- isn't an issue in itself. I have both a very short-stemmed drop-bar bike and a bike with swept bars where my hands can be a little behing the steerer tube or well in front, ie all poitions around the steering axis. It doesn't cause or influence shimmy, loaded or not. One bike won't do it as it's plenty stiff enough, the other I can induce a little wobble at a certain speed with luggage on the bike by artificially flexing/steering the bike, but it won't resonate naturally.

For ANY BIKE that is light enough to be comfortable to ride unloaded, there will be a set of conditions (load, rider weight, tyre, wind, surface) which will cause a shimmy.
You might not have found it yet, but its there all right.

Totally agree. I know of plenty of bikes that have been criticised (or at least critiqued) for being stiff, but they are far less prone to handling wobbles or even a shimmy when loaded than some slimmer-tubed bikes. For off-road or rough-road handling, imo a short stem adds control and increases your ability to correct a momentary loss of grip, or react to undulations in the surface mid-corner (assuming your bike and load suits this sort of riding in the first place). For riding steadily on good roads it's not an issue though, more traditional road geometry and fit, stem dimensions etc work fine.
by james-o
7 Aug 2016, 8:57am
Forum: Bikes & Bits – Technical section
Topic: B&M 'USB-Werks" + Garmin 1000 + B&M IQ-X
Replies: 5
Views: 764

Re: B&M 'USB-Werks" + Garmin 1000 + B&M IQ-X

I have a USB-Werk and an SON front light with a Garmin 800, so a different set up but fwiw - the Garmin 800 has a 2000-2200mah batterey as far as I know. It charges in about 3hrs of ~14mph average pace road riding (estimate from experience rather than a calc. I then leave it plugged in mostly as once full it's not pulling any more current anyway so the front light runs at normal/full brightness with the topped-up Garmin plugged in (garmin running a simple route line, not tracking and rarely on turn-by-turn directions). If you start with a full Garmin charge and keep it plugged in most of the time, I can't see any issues with the USB-Werk keeping it topped up. The -werk does lack the output of something like a Sinewave but it's been fine for a number of road trips I've done, keeping phone and Garmin full w/o juggling acts or particular attention to it all.
by james-o
19 Mar 2016, 10:28am
Forum: Bikes & Bits – Technical section
Topic: FRAME STIFFNESS
Replies: 79
Views: 4811

Re: FRAME STIFFNESS

Colin, imo you're bob-on re the head tube, TT and DT shaping in your first post. We did the same things with 'XX44' head sets and head tubes when I 'designed' (I like your use of inverted commas there, I agree, most of us specify frames, design is a stretch and over-used in the industry imo) the Genesis ti and steel bikes to use the 44mm ID head tube. Reynolds' first HT in that format was done for Genesis back then. I think you may use the same Ti supplier as Genesis did and they made a flat-oval TT for us for the same reasons, I see they make quite a few variations on it now. The flat oval tube idea had been done before, 1930s or perhaps before even that, but the 44mm ID non-taper HT pulled a few benefits together there. Vertically ovalised Ti DTs have drawbacks at the lower edge of the HT end.

And chainstays with minimal crimping, can't agree more. Sometimes needed but good to avoid.

Planing is a funny one. Like many things in BQ the point is well-argued and hard to dispute yet for me it comes down to feel. Either you like flex there and / or low trail or you don't. Bikes are about feedback and feedback loops as much as demonstrable engineering sense and proven mechanics imo.
by james-o
21 Feb 2016, 11:32am
Forum: Bikes & Bits – Technical section
Topic: Carbon fibre disk brake touring fork
Replies: 41
Views: 2723

Re: Carbon fibre disk brake touring fork

I'd agree with a lot of that Brucey. Commuting on salty or oily roads can make a joke of a disc pad pretty fast, the main con vs the generally weaker but predictably so performance of rim brakes in the wet. I've never found discs an issue with upsetting my balance on the bike, the power's there but the control makes it pretty hard to go OTB anything but a very steep off-road situation.

As for a carbon touring fork though, I'd not bother. I think the scare stories of carbon can be overplayed but still, steel just works so well.
by james-o
21 Feb 2016, 9:26am
Forum: Bikes & Bits – Technical section
Topic: Carbon fibre disk brake touring fork
Replies: 41
Views: 2723

Re: Carbon fibre disk brake touring fork

Disc brakes have their plusses and minuses, but for most of the winter there is no real benefit in terms of braking performance because that is limited by the grip of the tyre on the (wet, muddy, icy) road anyway.


For someone with your technical experience I'm suprised to read that. That point has been discussed many times elsewhere. Using good discs shows that it's all about how much feel or modulation you have up to that limit of traction - the gain is in control rather than ultimate stopping power that as you say is limited by grip.
by james-o
8 Sep 2015, 9:07am
Forum: Bikes & Bits – Technical section
Topic: 10 reasons to dislike drop/road bars :P
Replies: 123
Views: 10816

Re: 10 reasons to dislike drop/road bars :P

Image

Jones 'H' bar. Very useful fore-aft position variation. Depending what gear shifter is used, I can cover the brake with my 2 outer fingers from a narrow+fwd position and from the rear in the normal index-finger braking, that's around 4-5" of distance.

I have bikes without drops and I can see clear advantages to that set up until I have a headwind and limited time.
Yup .. The only time something like a Jones or trad M-bar is lacking the right position.
by james-o
6 Sep 2015, 10:08am
Forum: Bikes & Bits – Technical section
Topic: 10 reasons to dislike drop/road bars :P
Replies: 123
Views: 10816

Re: 10 reasons to dislike drop/road bars :P

Interesting topic. I love as well as hate drop bars. I love how they work on a ' proper' road bike yet I don't want to be limited to tarmac on my 'road' bike. I find drop bars challenging at best for riding off-road, at least any riding that's not pootling. I know John Tomac rode like a man posessed on drops but that doesn't help me ride anything like that way on the average easy MTB trail and they seem to limit the fun-factor. I think roadie drops came from track sprinting bars rather than anything with off-road or comfort in mind. The way the STI hood ergonomics have evolved means its a great 2-position set up but they're still a bit hopeless for anything tricky off-road, imo. You can set them up with a hi-rise stem so that the drop hook is in a better position to be used all the time, you get better braking yes but then the hoods are sky-high and it becomes a 1-position bar again, and in the case of flare drops the hoods have an odd position. In that case I think an M or H-bar is a better solution.
So on my other more off-road biased bikes I have Jones bars or some type of swept M-bar. These are great as the braking is generally better and a significant benefit is that the grip stance narrows as you move forward and widens as you move back, logically better for varied terrain imo and the main aspect where drops fail for me - the hood position is higher, suiting trickier terrain in many ways, but also more forward and less effective for braking and grip security (hydro discs can improve this quite dramatically though). But, and it's a big but, the swept M/H bars don't let me drop my position for headwinds or fast road descents. They encourage a more MTB-like handling approach that is great off-road and gives a bike a more relaxed, town-bike feeling on tarmac. So in many ways it's about my attitude on the bike as much as ergonomics and there's a compromise to make either way.
by james-o
27 Jun 2015, 4:59pm
Forum: Bikes & Bits – Technical section
Topic: Effect of bottom-bracket height
Replies: 17
Views: 3538

Re: Effect of bottom-bracket height

Yes 25 deg lean angle from the vertical, as the minimum lean angle. Should've clarified the 'minimum' bit : )
by james-o
27 Jun 2015, 1:24pm
Forum: Bikes & Bits – Technical section
Topic: Effect of bottom-bracket height
Replies: 17
Views: 3538

Re: Effect of bottom-bracket height

I think a higher bottom bracket and thus higher centre of gravity would make the bike feel more stable (the opposite of a car), much like a broom but not a pencil can be easily balanced on a finger.

This is the idea behind the 14" plus BB on Geoff App's Cleland bikes. An amazingly agile bike at low speeds. But for fast corners and good handling in general I like a BB that's as low as possible without getting pedal strikes too often. I think 10mm change there can make a subtle but worthwhile difference in cornering feel and control but only if you're pushing your cornering speeds a bit. Road bikes can be a fair bit lower than the 68-70mm that most race bikes use if you don't want/need to pedal through corners. The European safety standards require a 25 degree lean angle with the pedal dropped to the side of the lean so that tends to limit BB drop.
by james-o
21 May 2015, 6:55am
Forum: Touring & Expedition
Topic: Dirt road touring / bike-packing in Crete - info
Replies: 3
Views: 689

Re: Dirt road touring / bike-packing in Crete - info

Looks good .. I wondered what that area would be like for a trip a few year ago. Back on the list!
by james-o
21 May 2015, 6:49am
Forum: Bikes & Bits – Technical section
Topic: Recall Notices
Replies: 7
Views: 612

Re: Recall Notices

The Bicycle Association passes all recall notices to its members so the trade does get to hear of them. Perhaps a public-facing aspect of that would be good but to be fair they're simply passing info along, it's the manufacturer's responsibility for a reasonable means of contacting customers.