Bicycle Tech/Gear Discussion Thread

Jun 07, 2013 at 10:42 PM

I think it happened bc the original owner, my brother, rode them and he weighs around 200lbs!

Giving people broken components seems to run in the family. Like that time I have WDC a cracked stem. Remember that ole buddy? Haha. You almost died! Sabotage.

Jeff Owens

Jun 07, 2013 at 10:43 PM

Yacks, don't you have carbon tubs too?

WilliamDC

Jun 07, 2013 at 10:51 PM

http://youtu.be/z5rRZdiu1UE

twoyacks

Jun 07, 2013 at 11:02 PM

Jeff Owens said:

Yacks, don't you have carbon tubs too?

Indeed I do....they are race day only wheels.

"They say the Devil’s water it ain’t so sweetYou don’t have to drink right nowBut you can dip your feetEvery once in a little while" The Killers

http://www.youtube.com/watch?v=ff0oWESdmH0

Phil Maronilla

Jun 07, 2013 at 11:07 PM

Saw them at the Garden last month. Awesome band.

twoyacks

Jun 07, 2013 at 11:08 PM

I've been known to dip my feet in the Devil's water (carbon)....

dstokes

Jun 08, 2013 at 10:55 PM

Productive afternoon:

clean drive train
overhaul rear brifter (dicey proposition)
replace shifter cables & housing & new bar tape
swap out brake pads and put on carbon wheels

Hope it all holds up for the race tomorrow. . .

Able to leave a mess 'cause the wife is out of town; now off to the movies!

mugwump

Jun 09, 2013 at 01:53 AM

twoyacks said:

Wait are those carbon fiber reinforced plastic rims ??? Oh you are making this way too easy...I smell a booby trap !

http://www.flickr.com/photos/jam1ec/4664995001/

Yacks,

The wheel seen folding under a crashing Cavendish actually sprang back to true. Freaky.

twoyacks

Jun 09, 2013 at 02:56 AM

Alien technology? Maybe it was a Z-rim ?

Rotor
A guy nobody has ever heard of, Dale Cooper, invents a little machined aluminum thing that attaches to your stem and allows for tangle free rearbrakes.
ACS markets this as THE ROTOR.

Locking levers
Steve Potts has come up with a new brainwave. It's a neat little button on the lever that you press down to keep the brake locked on. ACS are making a new lever incorporating the new idea.

ACS Z-Wheels
ACS ad, february 1985: Track or tricks? Up to now you had to flip tor it. Nylon mag wheels are great for freestyle but they sure weigh a lot. Alloy rims are super light - but you can't thrash them. ACS Z Rims are the answer. Super tough Z rims and matching Z hubs combine all the strength of solid mag wheels with the weight advantage of plain alloy rims. Now you don't have to chose between weight and strength- At the track, in the air or on the street, lightweight ACS Z Rims will never let you down. Thanks to the unbreakable DuPont Zytel material, ACS Z Rims are virtually indestructible. And that's a promise: ACS will replace Z Rims and other ACS components If broken during normal use. Send damaged part only for free replacement. ACS Z Rims are available in white, black, red, yellow and blue, individual rims or complete wheels with ACS Z Hubs - they're at your dealer now.

?: ACS Z-Wheels were a popular type of wheel for the professionals. All colors with matching hubs. There was a rumor that if you placed them in the Freezer they would straighten out. From the experiences of my friends this didn't really work. But they did make nice decorations to the pile of old broken bike parts in my garage. Unfortunately they faded away quickly. Brakes wouldn't work well with them.

twoyacks

Jun 09, 2013 at 02:57 AM

viva the z-rim !

acs85zrims.jpg

Brendan Rigby

Jun 09, 2013 at 02:54 PM

phillip, regarding your fork, see the Technical FAQ here: http://velonews.competitor.com/2013/06/bikes-and-tech/technical-faq/technical-faq-valve-stems-wheel-migration-and-more_289611 (search for "Dear John")

if the clear coat is worn off and the underlying carbon has been scraped through, especially when you used the bike in an intended way, i can't see canndondale/the shop you bought it at putting up too huge of a fight? the key is that it's normal to put a 25mm tire on that fork and that it fits other forks. because the fork is different than others, it seems to have a manufacturing defect. those are bad news for manufacturers in terms of liability.

why should you bother? a) you don't know how long you'll have that bike but it won't be good to have a bike with semi-abraded carbon in the middle of the fork (not scrolling up to check out the amount of missing carbon but i'd be nervous to have any gone there); b) your new fork will accommodate the proper tire sizes!

go ask the folks where you bought it...maybe they'll tell you "25mm tires don't fit on caad10s" which would make things a bit more difficult

after shredding my tire last week en route to floyd, i'm not running 25mm 4seasons on my 52cm caad10. fits fine. i run them at 112 psi.

eragot

Jun 09, 2013 at 07:28 PM

Much too much air pressure. I run 100 in 25mm tires. I weigh more.

twoyacks

Jun 09, 2013 at 07:29 PM

112 psi???? the whole point of running 25's is to run lower pressure without pinch flats = increase comfort, contact patch and reduce rolling resistance. Run those pigs at 95 rear 92 front....JUST DO IT !

twoyacks

Jun 09, 2013 at 07:31 PM

U sir r a 25mm dilettante....

Jules

Jun 09, 2013 at 07:46 PM

Sweet Jesus - that's high

Brendan Rigby

Jun 09, 2013 at 10:45 PM

i lied. usually i do 107/102 in line with my weight according to that chart online somewhere.

i will begin doing 112 because that is what the manufacturer of the tire recommends for "race" use of that tire ("max tire pressure - .5 bar" = 120 PSI - .5 bar ~= 112 psi according to my math, which is likely wrong). until i see the smoking gun (or burning rubber) memo from continental's internal research arm that says "we actually think 96 is better for races, especially bumpy ones in abandoned toxic airfields", i'm going to boldly go where no man has gone before and listen to the words of the company that manufactures tires for some of the world's most demanding applications. see attached instructions that came with continental's tire. they were not tire-specific instructions, however.

when i'm just riding around, i might go to 96, which is what they recommend for that tire in "city" mode. yack's recommendation is only 1 psi off from what they recommend. although 92 front is scandalously low. i do say.

the last pinch flat i got en route to FBF really sucked, so i want to minimize that risk. willing to sacrifice comfort. "why get 25mms at all then?" good question. call me a dilettante

2013-06-06 21.44.30.jpg

twoyacks

Jun 10, 2013 at 12:24 AM

here is another offering....in aluminum....for your viewing pleasure....

http://road.cc/content/news/81272-first-spy-shots-finished-kinesis-aithein-frame

Brendan Rigby

Jun 10, 2013 at 01:31 AM

it comes in orange. like kissena!

dstokes

Jun 10, 2013 at 02:22 AM

http://bicycles.stackexchange.com/questions/2744/what-pressure-should-i-run-my-road-bike-tyres-at

Brendan Rigby

Jun 10, 2013 at 03:22 AM

yes! thank you david! that's one of the diagrams i used when i ran michelin tires; they made that graph and include it with their tires. an excellent idea. there's some other old diagram...but i can't find it right now.

i now use a different company's tires and go with their recommendation. here's continental's guide, which accords with stereotypes about germans by providing raw instruction instead of colorful graphs. rumor has it the german version is just one word.

it's ripped from the image i posted above. their recommendation varies with intended use:

city/touring: .8(max pressure)
MTB: .75(max pressure)
race: (max pressure - .5 bar) (food for thought. why no multiplication?)

it does seem that they recommend higher pressures than michelin overall. hmmm.

i wonder why continental recommends a higher PSI for races? maybe they think you'll be taking turns harder and putting increased load on the sidewalls? and the sidewalls will deform less with higher PSI? it seems that the "city rider" would hit more, not less, potholes than the race rider. or perhaps in a race, your extended use of the tires will heat them up enough that you're going to inflate to the max PSI anyway? maybe the .5 bar is just an estimation of expansion that will occur in a typical race use (i.e., extended use at high speed, high friction) of the tire?

mostly i'm experimenting. going over bumpy corners at speed and with the bike at a severe angle feels as dangerous as it is with my 23mm tires. i prefer the illusion of thinking that rear tires do not slide out in turns and crashes do not happen in bicycle races. one of my 23mm tires ripped and needs replacing, so i figured why not try 25s? particularly b/c of FBF and turn 1 @ rockleigh. 25mm is more rubber on the road. even though my calipers showed that inflated to 110 PSI, the new 25mm tire was the same width as the old 23mm tire. but that's diameter: maybe the circumference is larger w/ 25mm than 23.

as for tire pressure, one vendor says one thing, another says another. will i notice a difference? doubtful, but i'll defer to continental's wisdom on their own tires. then again, how different is one tire from another? this is getting way too complex. i just want to ride my bike and not get flat tires before or during races. that's the worst.

Continental-Tire-Instruction-Highlight.gif

David Yang

Jun 10, 2013 at 04:12 AM

@Brendan - When in doubt, consult Sheldon Brown

http://sheldonbrown.com/tires.html#pressure

Some highlights:

...Rough surfaces generally call for a reduction in pressure to improve ride comfort and traction, but there is a risk of pinch flats if you go too far. Even at the lower appropriate pressure, wider tires, because they also are deeper, are more immune to pinch flats.

...Most tires have a "maximum" pressure, or a recommended pressure range marked on the side of the tire. These pressure ratings are established by the tire manufacturers after consultation with the legal and marketing departments...Newbies often take these arbitrary ratings as if they had some scientific basis. While you'll rarely get in trouble with this rote approach, you will usually not be getting the best possible performance.

...Savvy cyclists experiment with different pressures, and often even vary the pressure for different surface conditions.

And here's the older guide that's linked on Sheldon's page:

http://www.bikequarterly.com/images/TireDrop.pdf

Overinflating, while avoiding pinch flats, has hazards of it's own.

An overinflated tire is more prone to damage from sharp rocks and similar road hazards.
An overinflated tire can bounce on surface roughnesses. This can cause dangerous interruptions in traction, particularly if it happens during cornering.

Brendan Rigby

Jun 10, 2013 at 12:10 PM

sheldon

Jules

Jun 10, 2013 at 12:34 PM

You guys have too much time on your hands

jim_nelson

Jun 10, 2013 at 12:53 PM

I think there is probably a difference between optimum pressure at which to avoid pinch flats and optimum pressure at which to go fastest. I'm about 160 (OK 162.5 this morning but I'm always a couple pounds heavier on Mondays) and I like right about 100 on my pump's analog gauge. I rarely pinch flat.

However, that brings me to a question I meant to post last week. Last Saturday morning while riding with Yang and Wes I DID pinch flat on a hole near 3rd Street in the park. They kindly stopped to watch me make the change and ended up helping because the tire was so GODDAMN tight on the wheel I could barely get it off and then I could not get it back on. I snapped a Park lever trying to get the thing back on. The combo is my Powertap wheel with a widish Velocity rim and a 23mm Conti GP4000S. I don't remember having that much difficulty when I put the tire on the rim initially but maybe it's just filed away in the "when this basket of frustration is full I put my head through a wall" portion of my brain. With David's help I finally got the tire back on the rim.

Anyway, not exactly sure what my question is here except maybe are there specific rim/tire combos that people have encountered that have been particularily hard to work with? Was it the narrower tire on a wider rim? Do tires shrink?

mugwump

Jun 10, 2013 at 01:27 PM

jim_nelson said:

Anyway, not exactly sure what my question is here except maybe are there specific rim/tire combos that people have encountered that have been particularily hard to work with? Was it the narrower tire on a wider rim? Do tires shrink?

Jim,

This is a classic issue. Rim diameters are not all the same, nor are bead diameters. Some combinations do work better than others. In my limited experience with wide rims, I've found them easier to mount and remove tires.

What's surprising to me is that the issue came with a Continental tire. In my experience, those are usually among the easiest to mount and remove. I typically don't need a lever to either put on Conti's or take them off.

And, no, tires do not shrink. If anything beads get stretched over time.

dstokes

Jun 10, 2013 at 01:44 PM

I concur with JP about specific combinations of tires and rims. Someday I'll tell you about my long saga riding across the country with a sub-optimal combination and lots of pinch flats (before I even knew what they were). But I don't understand the concept of a pinch flat with tubulars. Seems like it might be an artifact of Ragot's autocorrect algorithm.

With regard to manufacturer's recommendations, I believe they are more interested in covering their asses than optimizing your performance. Case in point, browse the following data about the actual shelf life of canned goods:

http://grandpappy.info/hshelff.htm

David Yang

Jun 10, 2013 at 03:42 PM

jim_nelson said:

Last Saturday morning while riding with Yang and Wes I DID pinch flat on a hole near 3rd Street in the park. They kindly stopped to watch me make the change and ended up helping because the tire was so GODDAMN tight on the wheel I could barely get it off and then I could not get it back on. I snapped a Park lever trying to get the thing back on.

Yeah that was a PITA. IIRC didn't the rim tape get caught under the bead or something and further mess things up? The tire itself was completely twisted and torqued looking when we were trying to ply it back onto the rim.

FWIW I have issues with 28 Vittoria rando tires onto a Mavic CXP33 for my commuter which is the opposite of your 23 tire/wide rim combo.

alyoshas

Jun 10, 2013 at 05:25 PM

to come back to pressure discussions: I do it by feel. I get on the bike and look how much the tire flattens out, if it's continuous with the rim...i'm good to go. I race Hed Jet 6 FR and a little bulge is good since its a wider rim than most I suppose. Also because it's a wider rim, it requires slightly less pressure and I find myself inflating 95psi in the back and 90 in the front for a criterium in dry conditions like white plains.

Jeff Owens

Jun 11, 2013 at 07:34 PM

So my Reynolds wheel is shot and they'll rebuild the hub around an Assault with new spokes for $450. Ehhhhhh.... Doesn't seem like that great of a deal.

Plus, I think the Boyd's (is the deal offer still up?) and others have the newer more stable/aero profile, like zipp Firecrest, no? Reynolds is still the old school thin/narrow.

Anyboyd heard anything about Novembers?

http://www.novemberbicycles.com/rfsw-wheelset/

David Yang

Jun 11, 2013 at 08:58 PM

@Jeff Owens - The set you linked just seems to be off the shelf hubs and rims since they say their Rail model is their first with a proprietary rim design.

http://www.novemberbicycles.com/rail/

Also, correct me if I'm wrong but isn't $450 < $790+35s&h? If the hubs are still good, $450 for someone rebuilding your wheels with new carbon rims and spokes seem pretty good to me. What kind of spokes?