Monday 13 August 2012

Servicing Shimano SPD Pedals

I love SPD pedals. But they're puzzling, because it's not obvious how to service them, other than keeping them clean and the release mechanisms (the bindings) oiled. So, here's a little post about servicing them. This is the PD-M520 bog standard pedal:

First thing to note is that the pedal unit (green arrow above) is screwed on to a splined threaded barrel (red arrow above, labelled (2) in the exploded view below). The splined threaded barrel goes over the metal axle. On the PD-M520, the barrel is made of PLASTIC! So if you try to use pliers to turn it, the splines will disintegrate (which may not be a huge problem if they are only ruined on two opposing faces, because you can still get enough purchase to tighten and loosen them again). Really though, it's best to use the proper tool, (11) below. Be sure to observe the arrow directions for loosening and tightening. You hold the pedal in one hand (easier to hold it in a cloth) and unscrew the splined barrel. 
I opened mine up and below is a photo. From L to R, the splined threaded barrel is shown located on the metal axle. Then there's a dished washer, a bush with ballrace cups on both circumferences, a cone nut and a locking nut. It looks like there are twelve tiny balls each side (I didn't measure them but Shimano tech docs say 3/32"). Also, shown in the exploded view above, there's a thin rubber ring seal around the axle just under the spline. Obviously to keep water and crud out. 
Below, you can see the ballrace cups in the bushing and the coned nut a bit better.
After cleaning it all up, I reassembled in the following sequence. Load up one side of the bushing (see below, on the right). Then pack some grease around the cone on the axle (see arrow below). Then, using a cocktail stick, press all 12 balls down onto the greased axle cone, and gently slide on the loaded bushing - unloaded face first of course. Then carefully spin on the cone nut, being careful not to dislodge the loaded balls and then the tiny lock nut.
Spend a few moments adjusting the bearing tension by turning the cone nut and locking the nuts down to each other. It's the usual game of trying to adjust the lock nut system to get free spinning movement with minimum (no perceptible) play. Slap on grease wherever there are parts rotating against each other. In total, it took me about 20 minutes to renovate a pedal that was grinding, hardly turning, into one that now spins freely. It's very clever, because the metal bushing which press fits into the pedal unit, seems to take all the load. Whirr! 

Monday 25 June 2012

Spa Cycles Wharfe Saddle, Seatpost Raleigh Twenty/BSA20

The Wharfe saddle from Spa Cycles is rather like a Brooks Swift...and a lot cheaper. This is what you get inside the box:
A little tool for the nose bolts, and a cloth bag to put it in. I fitted it to a new alloy seat post for the BSA 20, and added a Carradice Zipped Roll saddlebag:
It's quite a 'racy' saddle, and I wonder if I'd have been better off with the Nidd which is like a Brooks B17. We'll see, time will tell. 
Apart from improving the appearance, the new saddle n post saved nearly half a kilo in weight:

Old (g)New (g)
Saddle:910525
Seatpost and clamp:470380
Totals:1380905





Wednesday 20 June 2012

BSA 20, Raleigh Twenty clone

Since my beige colour Raleigh folder is with a cousin for use as a commuter, I recently picked up another bargain. It's a green, non-folding BSA 20 and this is how it looked on purchase:
The hub stamp and frame number indicates its an early 1978 model. That's the year of the film Grease, the hits Night Fever by the Bee Gees and Baker Street by Gerry Rafferty.

I've yet to decide what to do with it exactly. As I've been saying for many years, the Raleigh Twenty to a bike nut, is like a blank canvas to an artist. So far, I've merely pumped up the tyres, changed the rear brake inner cable (it was jammed with corrosion), oiled the hub, adjusted the toggle chain and generally lubed all round. Oh, and I did spend a fair amount of time unravelling a great deal of yellow knitting wool that I found wrapped around the rear hub and drivetrain. That's a new one for me!

Anyway, now I have a fully working, pottering bike for the grand sum of £15, plus cost of an inner cable.

So many possibilities... Perhaps I should start off with a strip and powder coat?

Monday 14 May 2012

Quick Release lever alignment

Michael Barry, the Team Sky professional rider, recently wrote about his favourite cycling innovation, the humble quick release lever (article here). The other day, I looked idly at bikes in a public rack. I noticed that people position the closed lever in many different orientations. Which way should QR levers point? A good subject for a "Chuck's Tech Opinion," I mused.
Sounds like a trivial matter? No way, I say! A good friend of mine had a minor crash on his beautiful all carbon bike. The front fork was gouged by the QR lever - a very expensive mishap. The lever had been locked in front of the fork blade, pointing up. I've also heard stories about a person who pulled a bike out of the rack, and only when riding discovered that the QR lever had been snagged open!

When you examine pro bikes, it's very interesting, as it seems that rear lever alignment is team, or should I say team mechanic, dependent. So, for example, TT bikes from Radioshack/Leopard Trek (including Cancellara), Vacansoleil (including Larsson), Saxo Bank (including Boaro), Astana (including Brajikovic) have the QR lever on the rear wheel pointing backwards, as in the photo above. The others have the QR lever positioned under the chainstay pointing forwards (e.g. Team Sky), or back and up, or in the crook between chainstay and seatstay like this:
"In the crook" also appears to be the way most pro cyclocross riders orient the rear wheel QR lever. I guess that is because the risk of snagging the lever (e.g. by a passing bush!) is lower in this position (it's tucked into the stays, which protect it a little). Another thing the pros have to worry about (but I don't!) is ease of access for wheel changes.

When it comes to the front QR lever, it's much simpler. Among the pros, as far as I can tell, it is always pointing backwards. Either under the fork, or backwards and upwards. The other pro thing is that the lever on the front wheel tends to be on the left side of the bike (on the rear wheel it HAS to be on the left side).

So, fwiw, here's my opinion. On the rear wheel of CX bikes and commuters that are often parked in racks with other bikes - where there is a risk of snagging the lever - I will orient it tucked into the crook of the seatstay and chainstay. Whereas for TT, I may have it pointing backwards. It really depends on the frame structure around the dropouts and the shape and configuration of the QR lever. I am not that keen on pointing it forwards and down under the chainstay - but I would do that if there is no other way (it depends on the configuration of the lever and type of frame - sometimes it won't go into the crook without fouling the frame, for example). On the front wheel, it's always pointing back, either under the fork or backwards and upwards behind the fork blade. Usually this is achieved with the skewers oriented so that each QR lever is on the left side of the bike.

And yes, I agree with Mr Barry that the quick release is a great bicycle innovation.

Saturday 31 March 2012

Is Shimergo a waste of time?

Shimergo means using Campagnolo Ergo shifter levers with a Shimano drivetrain. Check out this beautiful Bianchi renovation (from the interesting "Pistarice" blogsite):
I used to think that messing about, mixing and matching combinations of components from one manufacturer with those from another, was pointless. Each brand is designed to function with its own compatible parts. So obviously, it would be less than optimal to use bits that were never designed to work another brand, right? But no, both theory and practical experience indicate otherwise.

The most common combination seems to be 10 speed Campagnolo Ergo levers with either 8 speed Shimano drive, or 9 speed Shimano provided the rear derailleur clamp washer is rotated a bit (what Shimergo practitioners call "hubbub" - photo here). 11 speed Campagnolo shifters also work with Shimano 9 speed systems. However, since 10 speed Campagnolo levers (e.g. Veloce 10) are significantly cheaper than Shimano STI levers (whereas Campagnolo 11 speed ones are comparably priced), Shimergo is useful solution for:
  • upgrading Shimano geared bikes with down tube shifters - e.g. touring bikes, or old road bikes
  • converting MTB drive trains for road use
  • a cheaper and I'd say "sexier" option for replacing defective 8 or 9 speed Shimano STI shifters
  • in some cases, improving braking performance, because the Campagnolo brake levers are likely to be an upgrade over the original brake levers 
So, for certain bikes, Shimergo is certainly not a waste of time. What we need however, is some list of the known combinations of types and models that function well together (I mean with more product detail than the combination tables in Chris Juden's CTC article). And let's not stop with Shimergo. What about Sramano, which I have heard can work too? If any reader has first hand knowledge of a combination of mixed brand gear train parts and shifters that work well, please do add a little comment here with product and model details. If I can gather enough data, I'll make a table of it and share that interoperability info with everyone!

Thursday 29 March 2012

Peugeot Single Speed: more photos

I promised more pictures. Here is a rear view. Now sporting bottle cage, and yes, I preferred the green saddle (it's more comfortable actually).
Here is the internal brake cabling. Basically, just a hole in the top tube!
 The front entry hole.  You can just make out the bar end red LED lights. 
In the evening sun by the side of the road. Lovely!
So far, it's been a real improvement to my daily commute.

Tuesday 27 March 2012

Bike frame material: Is steel better than aluminium, carbon, etc?

Which is the best: steel, titanium, aluminium alloy or carbon? For that matter, what about bamboo and wood?!
Such questions have vexed bike designers for many decades. This post is not about the relative merits of each of these materials for bike frames, as there is plenty of information about that already (one of my favourite resources is here). Rather, I give my views on fitness for purpose and ride quality. I used to believe people who said that aluminium gives a harsh ride, until I bought a good alloy road bike, alloy front forks and thoroughly tested them in cyclocross. In my view, in practice, neither were harsh. I used to believe people who said the type of steel tubing really matters, and those who said 531C is the best, until I realised that it is not that simple. In the 1990s 7 steel bikes, identical except for the tubing, were built and blind tested (see this fascinating article). After much riding and reflection, the reviewer commented that the differences between the steel alloy bikes were very subtle - really rather minor. 

There are many ways to create a bike that works well and suits its intended purpose. Factors such as weight, shape, stiffness, tyres and saddle have a huge impact to how a bike works and feels. Ride quality is determined by so much more than frame material. I think there is a good way to look at this. First of all, think of all the things that make a bike efficient. What makes it go further, faster for less work input by you, the engine?! Then list the things that make your life on the bike more comfortable. After doing that, note that some of the comfort enhancing aspects serve to reduce efficiency, but even so, the increase in comfort may be worth it. So here's what I mean:

EFFICIENCY FACTORS
1. Bearings smooth. To put it another way, a jammed wheel would give atrocious "ride quality"!
2. Stiffness. Frame doesn't flex around when you push the cranks, descend at speed or turn
3. Wheels don't wobble, hop, or flop
3. Tyres have low rolling resistance 
4. A decent engine: rider has appropriate fitness and technique (my grandma ain't as efficient as Bradley Wiggins!)
5. Shape and size
6. Fitting is good, proper muscles engaged
7. Clipless pedals
8. Light weight
9. Aerodynamic
10. Components function efficiently 

Some of which work against the following:

COMFORT FACTORS
a. Tyre size and pressure - fatter, softer are more comfy
b. Saddle type
c. Suspension, whether through flexy frame or actual springs/dampers (which also add weight)
d. No nasty resonant effects - from high frequency teeth rattling vibrations, to scary front wheel shimmies
e. Relaxed seating position and rider view point
f. Contact points feel nice, allow subtle body shifts and position adjustments while riding
g. Components are convenient and comfortable to use

I hope you can see where the frame material fits into this. Basically, it contributes to 2, 8, a bit of 9, c and d. But any of the other factors could ruin the rider's experience of what is otherwise a great frame. Thus, all of the materials listed at the start of this article may be used to make a lovely bike frame that functions very well  - but only under particular conditions. Heavier tubing will make a stiffer bike. Both the load lugging touring cyclist and the road racer want a light, stiff bike but suitable frames are not the same in each case. Carbon fibre is great until it gets whacked or even scratched, when a small defect could make it dangerous through risk of catastrophic failure. Bamboo is natural carbon fibre! Modern super-steel alloys like Reynolds 953 undoubtedly make light, comfortable, strong, stiff, corrosion resistant frames, but so can carbon fibre composite, titanium and aluminium alloys. To underline my point, last season, Zdenek Stybar and Ian Field (world and national cyclocross champions) both used aluminium alloy bikes, while many of their world class competitors opted for carbon frames, but I don't know of any champion racers who used a steel frame. 

Ideally, your choice should be a personal one, based on real evidence and your preferences after test riding. After all, you will be riding the bike, not the person who gave their opinion on the frame material!