Recently on Cyclingnews.com |
 Bayern Rundfahrt Photo ©: Schaaf |
Tech letters for February 18, 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.
Send your emails to Cyclingnews' tech desk
Flight Deck Bracket
Cross brake set-up
Wipperman ten speed chain
650C vs 700C wheels
Bianchi Levitation wheels
Carbon rear stays
Crank length
Deda Synapsi handlebars
Pedal/shoe position
Speedplay Zero's V's SPD SL's
Time Impact Pedals
Tire wear
Wheels
Flight Deck Bracket
Just a quick line to ask if you know of a bracket that will sit my Flight Deck out in front of my stem.
I have seen photos of bikes with them on but cannot track one down, please help!
Paul
Tuesday, February 11 2003
Cross brake set-up
I have a cross bike that I really enjoy riding all year round, and I find that I am slowly using it more and more for 1-2 hour "mixed", mostly road rides. As such, I have been tinkering with my positioning on the front of the bike, trying to get things more in line with my road bike position, and I have had no trouble with this position on any of the trails I use (top-mount brake levers help a great deal). The problem is that I am having trouble properly routing the front brake cable under the stem I currently want to use; the negative angle of the stem causes me to have to bend the cable so severely that it sometimes feels as though it's binding up when I use it.
The position is exactly what I want and so I do not want to raise the height of the stem with spacers, which at some point would eventually solve the problem routing problem. Last year at some point I am positive I saw some pictures of some fancy hardware that brought the front brake cable through the stem face bolts and then dropped the cable directly to the brake from there. Does anyone know where I can get these? Does anyone have any other suggestions?
CJ
Espana
Friday, February 14 2003
Wipperman ten speed chain
I have a question concerning the use of the Wippermann 10spd chain on Campagnolo UltraDrive 10spd cassettes. Has any one had any experience with these chains? Are they better, last longer, stronger, etc. than Campagnolo's 10spd chains?
Mark Llewellyn
Tuesday, February 11 2003
650C vs 700C wheels #1
650c wheels became popular in the mid 1990s for mountain stages and Time trials, as well as for tri-athletes. ONCE and Mapei had some custom 650c Kleins and Colnagos for star riders such as Jalabert and Rominger. Also, 650c wheels were popular with female tri-athletes in the Hawaii Ironman.
Basically the pros of 650 vs 700c wheels:
Lighter
Faster to accelerate
Less wind resistance / more aero
Stiffer
Suit smaller riders
Cons of 650 vs 700c wheels:
Need a custom frame for 650c wheels
Need to use much bigger gears (55T ring can be hard to find)
Getting spare tyres (particularly spare wheels in a race from neutral service)
Resale (for us mere mortals)
650c wheels have fallen out of favour mainly for the above reasons, however Beloki used 650c wheels on his special custom mountain bike during last year's tour stages.
Nigel Smith
Pymble, Australia
Tuesday, February 11 2003
650C vs 700C wheels #2
A 650c wheel would be slightly more aero, although this is sometimes discussed since it turns faster at the same speed, thus making more rotational drag. It's sure lighter and stronger, thus can be made with fewer spokes (in theory) and this way compensating for the extra drag caused by the faster rotation, and yes, it should accelerated better because of a lower inertia. But not all things are nice on 650c wheels, since it's smaller, the tyre flex more on the contact point (ground) and this generates more rolling resistance. There's a lot of controversy on this debate of 650 vs 700c wheels, all things apart they seem to be very equal in terms of performance. All the extra advantage of the 650c wheels (lower weight, better acceleration and aerodynamics (?)) are in most cases neglected by the extra rolling resistance these wheels generate.
Who would benefit more from a 650c wheel? Here I believe in Cervelo's (www.cervelo.com) explanation: smaller riders seeking a low aero position. Anyone under 1.70m height is in trouble when trying to find a nice time-trial aero position. This happens because the 700c frame is already small enough that the head tube cannot be shortened further to put the handlebars in a lower position. One can lower its position many centimeters with a 650c frame IF this frame has a short head tube.
A great problem with 650c wheels is finding replacement items. Even a tyre can be very hard to find, narrowing the choices to a few brands and models. All in all, the 650c wheel is a system that can offer some advantage to smaller people. I see no use for them for taller people, just the headaches.
About the pedal revolution x speed it really doesn't matter because a 7 meter gear is a 7 meter gear, what happens here is that with a 700c you would be in a 17 cog while in a 650c wheel you would probably be in a 16, given that the chainring is the same size. What people do with 650c wheel to keep up with the same gear sizes of a 700c is change the chainring to a bigger one, for example, have similar gears people use a 42x55/56 on 650c chainring to duplicate a 39x53 on a 700c.
Marcelo Iannini
Brazil
Tuesday, February 11 2003
650C vs 700C wheels #3
Fortunately, 650c wheels are becoming less and less popular. If you are short and want a bike that fits properly, a 650c bike is a good choice. For all others, the drawbacks of 650c wheels are greater than the improved acceleration ability.
A 650c wheel will have a much harsher ride, higher rolling resistance, less aero since it will spin more revolutions at the same speed as a 700c wheel, a much greater chance of pinch flats due a lower volume of air and lack of availability that often leads to higher prices.
I always thought the perfect place for a 650c wheel is on a velodrome but they're even less common on the track than the road.
Jim Cushing-Murray
Tuesday, February 11 2003
650C vs 700C wheels #4
Zipp, the manufacture of high-end wheels, has an excellent article on this. The article can be found at:
http://www.zipp.com/TechInfo/wheel_rim_discussions/700_650.html
Gerald Chen
Tuesday, February 11 2003
650C vs 700C wheels #5
There are a number of differences that I have found having ridden 650c wheels for 13 years. Firstly, 650c wheels are definitely lighter and yes, they do accelerate faster, but the flip side of this is that they decelerate faster too! But compared to 700c wheels rotating at a given speed, 650c wheels with the same number of spokes as a 700c counterpart, produce more turbulence by way of the vortex effect of the spokes. They also have a slightly lower profile to the wind. Both of these factors are negligible and I challenge anyone to tell the difference.
But here is the big difference - 650c wheels are a lot more unforgiving (uncomfortable) especially on poor road surfaces over let's say an IronMan distance triathlon race. Believe me, I know. Also, on technical descents, 650c wheels are definitely more twitchy. Finally, 700c tyres are supposed to have a significantly lower rolling resistance compared to 650c tyres, especially the slightly wider tyres like a 23mm. Also, 650 tyres and tubes are somewhat more difficult to get hold of. You don't want to go on a long training ride with a bunch of mates, puncture a couple of times and run out of tubes/tubbies when all your friends have only got 700c bits.
Finally if you go the 650c route I would advise ensuring that you have a full carbon fork and maybe even a carbon rear triangle. Smaller wheels mean smaller, stiffer frames, which in turn means greater transfer of road vibration.
Victor Anderson
Wednesday, February 12 2003
650C vs 700C wheels #6
Man, this subject has been beat to death for years but the information stays in little known journals and rarely finds its way into the public realm. Basically the smaller wheels are faster, but the ride is not so good. One solution to this problem was extensively researched by Alex Moulton who sells a road bike with 17 inch wheels and a suspension system. His own tests have been confirmed by several independent research groups, including a General Motors test for their solar powered challenge car, that show small wheels have the same rolling resistance as larger wheels. Seems counter intuitive doesn't it? But then intuition tells us that apples fall faster than grapes and look what happened to Galileo for disproving that old theory! The reason the peloton rides 700C is largely because everybody else uses that size, and the UCI mandates wheels of at least 24 inch diameter for road racing. There have been attempts to use smaller wheels as Cino Cinelli tried in the early seventies, but the advantages just aren't significant. And darn it, the ride really is better with big wheels. Unless you ride a suspended bike. Ever try a full speed road sprint on a suspended bike? You will quickly guess why the peloton sprints with 700C!
Charles Rockwell
Wednesday, February 12 2003
If I remember rightly, what Moulton established was that the rolling resistance of his specially-made 17in tyres was about the same as some full-size tyres. That doesn't circumvent the basic maxim of tyre engineering that if you have two otherwise identical tyres at the same pressure, the larger one will have a lower rolling resistance. Tyre rolling resistance varies widely between brands and models. - JS
Bianchi Levitation wheels #1
I have a set of the Bianchi wheels, although I have yet to ride on them. I bought them for $250 Canadian (slightly used). The friend I bought them from said they're "OK". He replaced them with Ksyriums which he felt were lighter and stiffer. The Bianchi wheels are not particularly light (regular Ambrosio Excellight rims on Record hubs feel lighter) and require long stem tubes, which I don't need on any other wheels.
Jim Smith
Calgary, Alberta
Monday, February 10 2003
Bianchi Levitation wheels #2
Avoid the Bianchi wheels! We sold several pair on Bianchi bikes and every single one has come back to us with broken spokes. I wouldn't take a pair of these wheels even if they were given to me (and I've been offered a pair)
Chris Lowe
Tuesday, February 11 2003 (PST)
Bianchi Levitation wheels #3
I have two Bianchi race bikes, one 7005 SL with Levitation wheels and the other an EV4 with Campag Hyperon.
The Levitation wheels are significantly lighter than many rivals and are particularly good on rough roads. I seem to remember that they were reasonably priced, but are no longer featured in the Bianchi 2003 UK catalogue. Braking in the wet is very good. So far I've not had any problems or loose spokes. They look good too! The weight of the bike with intermediate spec Campag is about 18 pounds.
However, for absolute lightness and super smooth ride, you can't beat the Hyperons. The only drawback is price and inconsistent breaking in the wet. The EV4 weighs just 15 pounds, complete when fitted with these wheels (and Campag Record group set). I run it occasionally with the Levitations, but it is a chore to change brake blocks each time.
I find that using carbon wheels, cranks and seat-post, the bike tends to creak more than usual!
Jack Anziani
Buckinghamshire, England
Friday, February 14 2003
Bianchi Levitation wheels #4
The same wheelset is sold as a Avenir Equation wheelset in NZ without the carbon insert in the hub. They sell fro around $699NZ and weigh approx.1600g (705g front, 900g rear). 16 spoke front with 2 sealed bearing hur, rear is 20 spoke 4 sealed bearing and available with Campy or Shitmano freehub.
Try Repco Sport in Australia for Avenir products.
Stewart
New Zealand
Monday, February 16 2003
Bianchi Levitation wheels #5
Most of the Leviathon wheels I work on (I work at a Bianchi Dealer) are out of dish and don't true well. You can't true the wheels with the external nipples but instead have to use a tool inside the rim to true the wheel. The reason for this is the nipples are brittle and will break apart when a regular spoke wrench is applied to them.
The wheels are heavy and don't accelerate well, they have a slight aero advantage over a standard pair of wheels but the rim profile is not a 4-1 ratio so the aero savings are minimal for the expense.
Mark Legg
Tuesday, February 11 2003
Carbon rear stays
I've ridden scandium frames with and without carbon stays and found the difference to be far less than the hype would suggest.
The real reason carbon stays exist has nothing to do with performance and everything to do with manufacturing convenience and marketing. A traditional stay arrangement requires 6 welds: 2 at the seat tube, two for the brake bridge, and two at the dropouts. You can add a seventh weld if you want a chain hanger. A carbon stay eliminates all but one weld. It also eliminates have to cut and miter the brake bridge and stays. Instead you just mighter the wishbone plug, glue in the the of the unit and tighten a pair of allan screws at the dropout. This makes life much easier on the framebuilder. It also makes the folks in marketing happy because it gives them something new to sell. These are the real reasons carbon stays exist but good luck finding a manufacturer who is honest enough to admit this!
Chris Lowe
Tuesday, February 11 2003 (PST)
Crank length #1
I'd like to second Stephen Maluk's querry about crank length. That's exactly why I'm reading on the net today.
I'm 6'4" and 225# on 172.5's. Logic even if misguided seems to say: "Long legs = longer cranks."
I'm 52 and will ride 1,500 miles or so this season mostly for the pure joy of riding. It is much more joyful to go faster and easier.
I occasionally get to ride with some rather accomplished local riders and seem to have a disproportionate advantage downhill or with the wind (which means I can keep pace and even lead as needed). Unfortunately, that is counterbalanced by a disproportionate disadvantage as hill and wind resistance increase?
They say compliments on the flats but: "No one can hide in the hills!"
Naturally, I'd love fresh cranks, conditioning, or devices of any kind that helped me enjoy staying in touch with them .
The local shop had a Dura Ace 177.5 crank set on display calling my name at an advantageous price, so I bought 'em... then started reading and waiting for the snow to melt.
So far no mention of such long cranks actually being used anywhere.
There was a caution about the need to frequently clean the Dura Ace Bottom Bracket and a suggestion to move toward bullet proof by chosing the Ultegra bottom bracket?
Then there was the alluring tests of the RotoR cam cranks with mechanical advantages especially at cadence below 115 (I have no cadence above 110 any way), but with no reference to crank lengths available or how to chose properly?
I'm new to semi-serious cycling. Is it OK to answer a single question with three more questions?
Chip Littlejohn
Tuesday, February 11 2003
Crank length #2
I am not a pro, but I am 5'8" tall and use 175mm cranks. A former top US rider and friend of mine (who is exactly the same size as me) pushed me to go longer and I really like it so far.
Paul Whitworth
USA
Tuesday, February 11 2003
Crank length #3
I'm trying to avoid this from sounding like I'm having a go at Stephen Maluk (who wanted to know what length crank arms pro roadies use, and also what considerations he should weigh).
Surely it doesn't matter what length arms pro roadies use, and the only consideration should be whether it feels right? Pro roadies are truly in a very different league to us regular guys who just like to ride bikes. If it feels right it is right; it really is as simple as that.
James Reinhardt
Cape Town, South Africa
Wednesday, February 12 2003
Crank length #4
Crank length is one of my "new" discoveries (I wrote about this before in a tech letter Nov 21, 2002). I'm 5' 7", 29" inseam, and for 19 years I consistently used cranks ranging from 167.5 to 170 mm (I tried and discarded 165mm and 172.5mm). Until Oct 2001, I was using 170s. I switched to 175s after finding myself going as fast on flats on my 175mm equipped mountain bike (2in knobbies) as my 170 equipped road bike (TCR with Rev-X's). I tried riding the Giant on 170s after about a month on the mountain bike (I was waiting for, and received, a replacement frameset) but it felt like my brakes were dragging. I bought and installed the 175's (same model/brand as the 170s) and immediately started rocketing. Someone pointed out that it could have been due to the "new" muscles being used - many "innovative" workouts show big immediate gains only because previously unused muscles were recruited in the workout. However, after a full season of racing, I have duplicated and improved upon my results with less training.
If you are 6' 2" tall, I'd do what I told my best friend (who is 6' 2" tall and rides a 60-62 cm) - get some 180s. Spin them for a month or two before doing huge efforts, and then reap the benefits. Normally skeptical of such suggestions, he tried it and agreed. In thanks he sent me his (now useless to him) 175mm cranks. As they are beautiful carbon fiber cranks, I couldn't say no.
Aki Sato
Wednesday, February 12 2003
Crank length #5
At 6'2" anything smaller than 175 is likely to be a little small, but that does depend on several factors. Your inseam and foot size (often neglected) are a much better indication than height. I'm on the small side of the border between 172.5 and 175 since I have an 87cm inseam and a size 9 (43) foot (I use 172.5 for road, 167.5 for track, and 175 for TT's). Yout feet are important levers in your pedal stroke (even if your calves don't do a lot of the work) and your choice of crank length should take this into consideration.
Something else to think about is pedalling style. If you tend to grind (ride with low RPMs) then you'll likely love longer cranks (which in my opionion will only reinforce bad habits and will likely cause injury), but if you tend to pedal at a higher RPM and change cadences often then a smaller crank may feel more comfortable. I'd try them both out and see which feels most natural at 85-120 RPM at 5 RPM incriments and then see how they feel higher and lower after that. See which one feels natural at 90-95 RPM which is where you should likely be most of the time and the choice should seem obvious. Can't decide then? Go with 175 (which is what most pros your size would use). First and more importantly though, make sure you have an adequite cadence and a proper pedal stroke.
Matt Vogensen
Wednesday, February 12 2003
All the studies of the pedaling action of very experienced riders that I have seen show little or no articulation at the ankle. The foot adds to the total length of the leg, but it's not a vital lever in itself.
Crank length #6
Based on your height, I would recommend 175 cranks, but you may find the 172.5 's ideal. I'm 5'9" and use 172.5 but go shorter on my TT bike. While you may gain more torque and leverage with longer cranks you need to still turn the pedals! Crank length can be very personal.
Chris Harnish
Champion Sports Network
Monday, February 17 2003
Deda Synapsi handlebars
I visited EICMA in Milan last September, where I also fell in love with the Synapsi. The folks from DEDA told me that UCI had already approved the bar for mass starts, but other exhibitioners/producers told the opposite.
I asked UCI directly on this matter, and they told me in an e-mail-reply, that the Synapsi is NOT allowed for mass-starts but ONLY for time trials.
Damn. So what is the point really with this stem/bar? I can only imagine it used on mountain-TT's if used at all.
What do you think about this?
Sven Jenisch
Denmark
Tuesday, February 11 2003
Pedal/shoe position
Regarding Evan Ruzanski's shoe/cleat dilemma: The best advice I have seen regarding the biomechanics of cleat/pedal position and pedaling forces was on a website called www.analyticcycling.com (I haven't checked it in a while). You might want to consider in particular the "shin length" measurement presented on their page and how fore-aft cleat adjustment might influence it.
There was another website that proved (I believe using a Nissen-Orzo based computer model) that the best position is the tried and true ball of the foot over the axle. If anyone else has seen this website, perhaps they could point Mr. Ruzanski in the right direction, as I cannot seem to remember where it was posted. The gist of the website seemed to be that too far aft caused undue calf strain, while too far forward caused loss of effective downward thrust.
Jay Mueller
USA
Tuesday, February 11 2003
Speedplay Zero's V's SPD SL's #1
If you tend to have knee problems, then there is no way around the Lollypops. You will need the float, that the SL's don't offer. The "Lance"-pedals might be very high rated and this with good reason, but you have to consider your body's/knees' demands for float. Think function and health and not design and "Lance"-factor :-)
The Team CSC is riding with Speedplays this season, and they seem to ride fast, so the loss of power issue might be in theory. The pedal itself is very small, true, but the cleat's size compensates for this.
Sven Jenisch
Denmark
Tuesday, February 11 2003
Speedplay Zero's V's SPD SL's #2
I've been using the Speedplays for years and would highly recommend them over the SPD SL's. If you're worried about loss of power due to the center of the pedal being at the end of a long spindle: don't. You'd have to be superman to flex it. People are also often afraid of the small pedal not providing enough support for the foot. The massive size of the cleat keeps that from being an issue. With their low weight, float, double sided entry, and now adjustability with the Zero's, I really don't understand why everyone isn't using them.
Gabriel Byrne
California
Tuesday, February 11 2003
Can I just say I thought you were terrific in The Usual Suspects? - JS.
Speedplay Zero's V's SPD SL's #3
I've been using Speedplay Zero's for a few months now after switching from my old Look-style Shimano Pedals and I would highly recommend them. The main reason I was drawn to them was the double sided entry making my starts a lot easier but I am really satisfied with the whole package. The adjustable float means that you can have your foot anywhere in relation to the pedal. Also, they critics were arguing that the free float, not the platform, of the X (and partially Zero) series would subtract power but I found that the zero's feel almost exactly like my Shimanos in terms of float.
Max Spirin
USA
Monday, February 10 2003
Speedplay Zero's V's SPD SL's #4
Anybody disparaging Speedplay pedals for "potential power loss" needs to learn a little bit more about physics. It's the shoe that will potentially cause this; modern, stiff-soled biking shoes will eliminate the issue. Once your shoe is acceptable, calculate the additional weight you need to lift given the delta in weights between the different pedals; the answer will quickly convince you that light is right. I own Speedplays and Sidi Ergo shoes; it's a great combo, and I can't feel any flex at all.
Mark Andrews
USA
Tuesday, February 11 2003
Speedplay Zero's V's SPD SL's #5
I have used Speedplays for sometime as well as Time. And have won races with both systems. Speedplay much better cornering clearance. I never noticed a loss in power with them. The only issue is that the float is extreme so if you can get used to that they are really very nice.
Joey Coddington
Tuesday, February 11 2003
Speedplay Zero's V's SPD SL's #6
I rode Speedplays for years. I originally choose them to protect my knees. A job they did very well. One adjustment you must make with Speedplays (or downside, depending on your point of view) is dealing with the float when you want to put more power to the pedals. Like climbing out of the saddle. It can feel like walking on ice the first few rides. But it is absolutely something you get used to. What I could never get used to, though, was a hot spot on the soles of my feet right above the lollypop. Lots of different shoes, same hotspot. Last summer I switched to Look pedals. I miss the degree of float I had with the Speedplays and the belief (perhaps exaggerated) that my knees were very, very well protected. My Looks have float adjustable up to 9 degrees, which so far has left my knees perfectly happy. And what I really love is the broader platform of the Looks. No more hotspots and power transmission feels much stronger and more direct. I miss certain aspects of Speedplays, but I'd never go back.
James Overall
Tuesday, February 11 2003
Speedplay Zero's V's SPD SL's #7
I have used the Speedplay X2's for about 4 years. They have been fantastic. Absolutely no concerns about knees, loss of power (where the hell did that come from?) or pulling you shoe out. The best shoes that I think go with them are made by Time. The Time shoes have a flat area that you can fix the cleat directly on to. You don't need any adapters, and it brings your foot really close to the axel.
David White
New Zealand
Tuesday, February 18 2003
Time Impact Pedals
The Time Impact pedal is great for many reasons, the best being that you can crank the living s#$* out of the tension and your foot will never release in a sprint. I can recommend them to anyone who needs to feel a big pedal under their foot no matter what shoe they use. I have ridden them on a pair of Sidis and my favorite DMTs. However, as to the Perry Stone comment, the paint wears off after about 3000km or so and the pedal's sharp end tends to tear up the bottom of carbon shoes.
James Whitesides
Kalamazoo, MI, USA
Tuesday, February 11 2003
Time Impact Pedals #2
The shoes are the problem. I had a pair of the 2001 Northwave Evolution and yes I could not adjust the cleats to get the feet closer to the cranks. And I have 2 plates, the Time and the Look plates. I tried them both. With the Look plates I was able to get my feet a little closer to the cranks than with the Time plates. Then I compared the plate's bolts position of the Northwave shoes with Shimano SH-R 212, the Shimano shoes would put my feet closer to the cranks. I used the Look bolt pattern of the Shimano SH-R 212 to mount the Time Impact cleats, and that worked fine. It got my feet closer to the crank arms like I wanted.
I like the Shimano SH-R 212, but I can't speak for their other shoes. The 212 has a stiffer and thinner soles than the Northwave Evolution. So my feet are closer to the pedal axle; hence, more efficient pedaling. I have since returned the Northwave Evolution and am presently using Shimano SH-R 212 with the Time Impact pedals.
Rithana R. Chea
Tuesday, February 11 2003
Tire wear
Russ Williams writes: "You should rotate your tires front to rear, if they are not specific to either end, every 1,000 miles or so..."
I used to do this myself until I read the following article by Sheldon Brown on his website: http://www.sheldonbrown.com/tire-rotation.html. Keeping the good tire in front sounds wise to me... new one on the front, front one on the rear, and the worn out rear one into the pile of "wind-trainer" tires.
Travis Hartman
USA
Tuesday, February 11 2003
Wheels #1
I agree with the wisdom of "solid and steady" and when setting up my dream bike (titanium with Campag Record) I went the sensible option of Record hubs and Mavic rims. The whole package has been wonderful for me. But - be aware - I had my front rim spoked radially (because it looks good) and recently avoided near disaster when I noticed the spokes were pulling the flange away from the hub with the aluminium cracked in a concentric fashion for about 3cm.
Now I must decide - a new Record hub and build with spokes crossing - or are Record hubs inherently crackable? Any other experiences out there?
Damon
Australia
Wednesday, February 12 2003
Most hub makers warn against radial spoking as it loads the hub flanges in directions they're not designed for. Stick with tangential spoking and you should be fine. - JS
Wheels #2
Your points are well taken, but I offer two slightly different perspectives.
1 - A perceived advantage is an advantage.
2 - I have the ability to ride about $1,000 worth of my $3,000 bike. But when
I get back from a training ride, I absolutely know that what was ultimately
responsible for my performance was me. The other $2,000 is insurance.
Jim Preis
Tuesday, February 11 2003
I certainly can't argue with your first point, Jim. However, I find it's cheaper to convince myself that all these super-duper modern gee-gaws won't make me go any faster! - JS
