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Tech letters for April 9, 2003
Edited by John Stevenson
Confounded by carbon fiber? Need to sound off about superlight stuff? Tech letters is the forum for your gear-related questions and opinions.
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Electronic everything
Pro wheel choice
Shim vs post
Lefty rack
Campy 10 speed chain links
Codes on bolts
Crank length and knee angle
Headlight computer interference
Roof rack bike holders
Spinergy Spox
Tacx IMagic
Tyres
Electronic everything
Just a thought. We've now got common and commercially available:
- power sensors (Powertap, SRM, Polar just to name a few)
- cadence
- speed
- electronic shifting (Mavic and the new Campy).
We could take all of this info (much of which is wireless therefore easy to tap into) and feed it into a central unit that continually monitors the speed, cadence and power, and changes gears accordingly. Bingo, a workable automatic bicycle, that could operate in a number of ways (i.e. constant cadence, constant power, etc)
I know it's possible, the question is will anyone take the steps to make it commercial?
Simon van der Aa
Australia
Tuesday, April 8 2003
Pro wheel choice
It seems that it has become more and more prevalent to see pros running a deep dish aero wheel in the rear and a standard wheel in the front. Is there any advantage to this?
Jason Kilmer
Thursday, April 3 2003
Shim vs post
I just received my custom Guru Racelite frame with Dedacciai U2 tubing. This frame has a rather large seat tube diameter (35mm), so it came with a 27.2mm shim. Should I use the shim or purchase a seatpost that fits the frame?
Rene Decquir
Sunday, April 6 2003
Lefty rack
I just purchased a Cannondale MT bike (F800) with a Lefty fork. Is there a mount available for use with my pickup truck rack? I would hate to lie the bike down on the truck floor during long hauls.
Steve Justice
Thursday, April 3 2003
Campy 10 speed chain links #1
I snapped two 10 speed campy chains (joined at the LBS with the correct tool). In both cases they broke at the joining link. Ever since then I have joined the chains in the "normal" fashion and had no problems. From my experience the joining link should be called the weak link? In both cases the chains broke within 2000 km of riding. The chains joined without the joining link have run for 5000km with no problems.
Lee Bolden
Thursday, April 3 2003
Campy 10 speed chain links #2
Two good questions, and to answer your first one is YES. I put them on the same way as the old chain. I have been a mechanic for 25 years and have never had a chain break on me (6'3" x 220 lbs.) Only about two years ago, when I first went to the Campy 10 spd., and only because it was new and foreign to me. I put the chain on the way Campy say's you should. Well, in about two months, my darn chain broke on me. I put it together the old fashion way and have never had a problem again. I spoke with Campy directly about this and they said I shouldn't have done this? But now, if you buy a new Campy chain, they don't use that special link anymore, they have gone to a special chain pin just like the Shimano has for years. So maybe Campy finally realized that they had a bad thing too and have made the proper changes?
Dan Plummer
Thursday, April 3 2003
Codes on bolts #1
Codes on bolts do have meanings. Try this link for more information.
www.rockcrawler.com/techreports/fasteners/index.asp
From: Troy Mault
Thursday, April 3 2003
Codes on bolts #2
The 'codes' on bolts refer to the grade, or strength of the bolt. Grades commonly found on bicycles include 8.8,10.9 and 12.9. The first number refers to the ultimate tensile strength of the material used in the bolt, the second the ratio of the tensile yield strength of the bolt. For example, the material of an 8.8 bolt has a ultimate tensile (breaking) strength of about 800 MPa, and a yield strength that is 80% of that, about 640 MPa.
The yield point is the stress level at which a material will deform to the point that it will not return to its original shape. The ultimate material strength is the stress at which the material actually fails, in the case of a bolt, when it breaks.
Rob Moore
North Vancouver, BC
Thursday, April 3 2003
Crank length and knee angle
It might seem counterintuitive, but shorter cranks often allow people with short legs to produce more power (yes I know that power and leverage are different things) and push bigger gears. I (5' 5"), and many other smaller riders, have found longer cranks contribute to extreme knee angles at the top of the pedal stoke that result in large dead spots and reduced performance when pedaling seated. It may be due to pedaling style: I like to sit back in the saddle and push a big gear forward/ over the top of the pedal stroke. I am now thinking about switching back to 165's to improve my time trialing and climbing.
Gen Kogure
Thursday, April 3 2003
Headlight computer interference #1
Me again - I've been pondering your problem some more I think that a possible fix would be to enclose your light in a metal mesh to make what is called a 'Farady cage'. Depending on what frequency the wireless computer operates - it should be marked somewhere on the packaging or on the computer itself. Depending on frequency of operation the voids you can have may be acceptable to let light shine out. A way to check if there is any hope is to wrap your light completely in Aluminium foil with it on and see what happens.
I used this idea to solve interference problems for volunteer firefighters whose old ignition systems were interfering with the radio. I'm on the cycle2max.com website so you can contact me though that and you can give me more information and I'll be able to help better.
Having the light upside down may work giving a little shielding through the aluminium or steel handlebar.
James Hall
RF Engineer
Melbourne Vic
Friday, April 4 2003
Headlight computer interference #2
In regards to the letter from a former NiteRider customer svc manager about interference from NiteRider lights, I have one (DP12E), and it has caused interference problems with my Specialized SpeedZone Pro wireless computer.. However, I was able to remedy this with simple shielding made from several layers of heavy-duty aluminum foil (Reynolds brand in the US). I had to do some experimentation to find the right positioning, and also found that wrapping the whole head unit of the light was not as effective as simply placing foil between the head unit and the computer.
I have the bike head unit mounted just to the right of the stem, and the computer mounted as far to the left of the stem as is comfortable. I also have the transmitter mounted on the left fork stanchion, and had to experiment with its placement to get things "perfect"--ironically, the best placement of this transmitter is closer to the dropout rather than up higher--I think the line-of-sight was better.
So, interference issues can be handled, but it takes experimentation and an open mind.
Chris Cleeland
St. Louis, MO USA
Friday, April 4 2003 (CST)
Roof rack bike holders #1
I use a Thule roof mounted bike carrier on my Subaru Outback. I prefer the fork mounted model. You remove the front wheel and secure the bike via a robust locking device which operates like a quick release skewer. The bikes are mounted so securely, I reckon an Olympic gymnast could train on them for the parallel bars.
Go to www.thule.com.au and use the Australian Fit Guide utility to choose the correct model for your particular Peugeot 307 model and to locate a dealer near you.
Carlos Remedios
Sydney Australia
Tuesday, April 8 2003
Roof rack bike holders #2
Peter didn't mention which model of Peugeot 307 he purchased. Assuming it was a PEUGEOT 307, 5-dr, Estate, you could fit it with a THULE 755 foot and a 861 crossbar. Once you have this set up, there are numerous THULE bicycle carriers you could install.
Ted Niedziela
Southbury, Connecticut
Tuesday, April 8 2003
Roof rack bike holders #3
Go to a company called
Roof Carrier Systems
469 Burke Road
Camberwell
PH: 03 9822 9539
They are pretty helpful and do nothing else but roof racks and have quite a few options. I got some aftermarket ones for my Holden Astra and it was a lot cheaper than the dealer offerings. They do a number of European brands so the Peugeot shouldn't be a problem.
Tell them you know a guy called Mike Englisch (SKCC) and they'll probably give you a discount too.
Dave Coultas
Melbourne
Friday, April 4 2003
Spinergy Spox #1
I've had a pair of Spinergy Spox R1 wheels for three years now - without any problems. I've now ridden them about 7,000 km on nice paved roads, terribly rough roads and even a bit of single track. They still seem to be in great shape and I really enjoy their lightness and "cushioning" on harsh roads.
I did have them completely retensioned once during this time because after a flat (I rode on the rim a bit before realizing the flat) the wheel was slightly out of true.
I, too, have read reviews and even went as far as querying Spinergy directly about the quality concerns and whether it was safe to use them on an indoor trainer. I was assured they were okay and all problems had been fixed. They were really quite responsive to my concerns.
Sheila Ascroft
Thursday, April 3 2003
Spinergy Spox #2
I bought a pair of Spinergy SPOX used and put them on my cyclocross bike. I have rarely taken them off of the bike in the last three years. They have held up well on the road, moderate singletrack and fire roads. I never used them on the road bike because they flex too much for me. The only problem I have experienced with them is some breaking of the nipples on the rear wheel. I have broken three. This can be a problem with alloy nipples in general. You may want to contact Spinergy to get some spares since they are not commonly available at bike shops.
Mike Lockhart
Thursday, April 3 2003
Spinergy Spox #3
I have a pair of sew-up Spox from 2 years ago that have held up quite well. I use them almost exclusively for racing, but they have seen a lot of hard miles on bad California roads. Almost every race, someone comments on how bad the wheels are supposed to be, but aside from needing to re-tighten the rear hub periodically, they have been maintenance and problem free. Hopefully, I did not just jinx myself.
Jeff Cleary
Thursday, April 3 2003
Spinergy Spox #4
Hi Robert,
I have been using a set of R2's on my audax bike for 18 months now.
I have had 2 spoke failures in the rear wheel, 1 at the 100k mark of a 300k; I wrapped the spoke in with the others and completed the ride, the wheel remained true during this. The 2nd failure was at the early part of a Grimpeur, again I completed the ride. In my case both failures were rear wheel and at the end of the spokes.
I have read a lot of negative reviews as well, I believe on the whole that they are accurate and correct; however I when they are OK (most of the time) they are light. Comfortable and very smart.
Note that I weigh 140lbs, so it could be I have just got away with this because of my weight!
Russell Smith
UK
Friday, April 4 2003
Spinergy Spox #5
I've been riding Spox on my road bike (a Bianchi Campione, steel frame/carbon fork) since Spring of 2000. I love them. Light, stiff, great acceleration especially when I occasionally switch to my Open Pro rims I notice this. They also stay true.
I'm a competitive mountain biker, and use road riding for training, I ride the Spox on the road pretty hard, probably hitting more pot holes, and jumping more curbs than the average roadie...All I mean by this is that I definitely abuse the wheels to the fullest. Of course I only weigh 145 lbs.
The mechanic at the local shop has expressed his dislike of the wheels because of how hard it is to work on the wheel compared to "conventional" wheels.
A few weeks ago I broke a spoke while riding on a flat road at an easy pace, which was the first negative experience I've had with them. Replacing the spoke was not difficult, but was more time consuming than a traditional spoke, but I did it myself in about 30-45 minutes.
The mechanic also told me the design problem with the wheels is at the juncture of the nipple to the hub. You'll notice the nipple has a round/flat flange that holds it against the curved surface where the hub receives it. The flange should have a round/curved flange to match the curvature of where the hub receives it. Does that make sense? That flange is, according to my mechanic, the piece that has failed on people. It makes sense to me, but all the same the Spox wheels have held up really well for me, and I plan to ride them as long as I can.
Chris Bevens
Friday, April 4 2003
Spinergy Spox #6
I was involved in a test of wheels for a company. The spox scored higher then any other wheel except their own in rotational inertia. However we did notice that the nipples did corrode some. We did not experience a failure of any sort and the wheels rode well. I did feel like I had a flat all the time though. I have not heard of any failures, but I have also not seen many still around.
Joe Coddington
Tuesday, April 8 2003
Spinergy Spox #7
I used spox wheelset for two years and never trued them, I have heard of failures as well I think this is from over abuse (freeriding or heavier riders 200lb) I would have kept mine, but when I was hit by a car(not hard) the rear wheel bent and that was the end of the affair.
Darren Biggs
Thursday, April 3 2003
Tacx IMagic
I bought an i-Magic for training indoors this winter and have been somewhat under whelmed.
1. The Capricorn terrain is rather limited with no long hills. The idea of a virtual world you can choose to steer your own course around is interesting, but needs more variety. I ended up buying the Netathlon software, which offers some features the i-Magic software does not as well as more varied terrain. Netathlon does not use i-Magic steering.
2. I have never been able to get the USB interface working under Windows XP, despite help from the US and NL Tacx people. The Windows hardware wizard just won't recognize the driver as being valid. I have to reboot into Windows 98 to use the thing.
3. The i-Magic heart rate sensor reads the Polar cadence sensor as heart rate. I thought it was strange that my heart rate with no chest strap equaled my cadence until I figured it out. With a heart rate strap, the program reports inaccurate heart rate and goes wild every once in a while. Tacx plans no fix for this.
If I had it to do over, I probably would go for the Computrainer, a more mature and serious device.
Steven A. Marks
Thursday, April 3 2003
Tyres #1
For interested in tire rolling resistance, there is a detailed study on the subject available at www.terrymorse.com/bike/rolres.html.
David B. Dowling
Thursday, April 3 2003
Tyres #2
At best this discussion regarding tires shows no agreement amongst riders. Wear can be tested but I don't think you can test tires to determine their resistance to punctures or side wall cuts. I think it is simply a matter of luck. No matter what the manufacturers say, the difference in rolling resistance between two high quality clincher tires of the same width and using the same air pressure is so small that it is barely measurable and not significant. Ride liveliness depends on the suppleness of the side wall. Generally speaking, tires with a high thread per inch count allow for thinner side walls that will be more supple and they will retain the suppleness at a higher air pressure.
Jim Cushing-Murray
Thursday, April 3 2003
Tyres #3
If you are looking for the best all around tire Vittoria is hands down the best! They don't have the exposure in the US like Conti or Michelin, but they build the best clincher. The Corsa CX has a 290tpi casing and other tires just can't compete with the ride comfort, or quality (superb cornering, low rolling resistance). The Rubino is a longer lasting training/racing tire and also has superior ride characteristics. Sure a lot of the pros have to ride there sponsors tires, but when they get a choice, I've seen lots of pros choice to ride Vittorias. Also, if you notice, lots of pros ride tires with no decals or labels. Many of them are Vittorias.
My second choice would definitely be the Michelin Pro Race. I have them on my training bike, and have over 2000 miles without a single puncture! They corner well and seem to have a lower rolling resistance.
Last, I would choice the Conti GP3000. I have had numerous people tell me that they are very sketchy in wet conditions, and they don't feel as confident cornering. Also, in my opinion they are way over priced. On the other hand, Conti does make some of the best tubulars, but again, they are really expensive.
Choice of tires really comes down to ride style, and personal preference. I think it's better to spend more money now, and buy a few different tires. Use them for a short time, and find out which one suits you better and they just sell the rest. This way, in the long run you know exactly what you are looking for!
Jason Kilmer
Thursday, April 3 2003
