Advertise on Bikeforums.net



User Tag List

Page 8 of 49 FirstFirst ... 67891018 ... LastLast
Results 176 to 200 of 1205
  1. #176
    Senior Member
    Join Date
    Sep 2012
    Location
    England, Great Britain
    My Bikes
    Tarmac/LangsterPro/Epic
    Posts
    259
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dro.pru View Post
    Thanks Quinn8bit.

    I prefer clinchers but thank you for the site! (Quick search shows they have the same wheel in clincher)
    Miche also made the Pistard wheelset in clincher (I had a set on my first track bike). I just searched Wiggle because I knew they stocked them, not anymore it seems...

    http://www.ribblecycles.co.uk/sp/roa...ft190000000000
    Last edited by Lew.; 12-22-13 at 11:11 AM. Reason: Link
    Epic/Tarmac/Langster Pro

  2. #177
    Member
    Join Date
    Dec 2013
    Location
    NJ
    My Bikes
    Windsor Hour Track Frame, Motobecane Cafe Fixed, Gravity Road Bike
    Posts
    41
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Lew. View Post
    Miche also made the Pistard wheelset in clincher (I had a set on my first track bike). I just searched Wiggle because I knew they stocked them, not anymore it seems...

    http://www.ribblecycles.co.uk/sp/roa...ft190000000000
    Thanks Lew. I'm in the states, but at that price its cheaper than velomine aftercurrency conversion. I have to check the shipping.

  3. #178
    Senior Member
    Join Date
    Sep 2012
    Location
    England, Great Britain
    My Bikes
    Tarmac/LangsterPro/Epic
    Posts
    259
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dro.pru View Post
    Thanks Lew. I'm in the states, but at that price its cheaper than velomine aftercurrency conversion. I have to check the shipping.
    Ribble do things *super* cheap, but I thought they shipped to the states?
    Either way, I posted the link as evidence they exist. If I remember right, Ribble are out of stock at the minute anyway...
    Epic/Tarmac/Langster Pro

  4. #179
    Resident Alien Racer Ex's Avatar
    Join Date
    Jul 2007
    Location
    Let me check.
    My Bikes
    Of course.
    Posts
    11,238
    Mentioned
    14 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by carleton View Post
    Everyone I know who has used the Miche cog system was OK with it. They never gushed that everyone in the world should use it. It's an OK system if you have it.
    I have it. No chain whip is nice. At least that's what my knuckles say .

    I've seen a number of spun cogs, and one spun Miche carrier. If you do a lot of on/off and your hub isn't robust the odds of ending up with buggered threads is pretty good (the Miche carrier spun on an old, well used Zipp disc ridden by a sprinter).

    40+ years of being a mechanic makes me leery of high stress areas that are constantly being taken apart and put together.

    Don't know why they didn't go to a coarser thread on these things; dirt track motorcycles have a similar set up with a knock off nut and the TPI count is really low...dirty environment and no issues.
    Last edited by Racer Ex; 12-22-13 at 05:16 PM.

  5. #180
    Elitist carleton's Avatar
    Join Date
    Jul 2005
    Location
    Atlanta, GA
    Posts
    10,931
    Mentioned
    6 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by usheen View Post
    I have 48 and 50t chainrings, 13,14,15,16t cogs, and I want to get 2/3 new chainrings for a better gearing selection, should I get 47+49 or 49+51?
    Look here: http://www.bikeforums.net/showthread...ew-track-racer

    That guide isn't set in stone, but it's a good guide.

  6. #181
    Member
    Join Date
    Dec 2013
    Location
    NJ
    My Bikes
    Windsor Hour Track Frame, Motobecane Cafe Fixed, Gravity Road Bike
    Posts
    41
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Lew. View Post
    Ribble do things *super* cheap, but I thought they shipped to the states?
    Either way, I posted the link as evidence they exist. If I remember right, Ribble are out of stock at the minute anyway...

    yeah, thanks for that other source. I have to see how much is the shipping, if i have to spend whatever I save on the wheels then it is not worth it.


    My only concern is the radial laced front wheel. I've always been wary about it in general (Nothing like a classically laced wheel in terms of strength). Even more so since I'm a heavier rider (200 lbs). That being said I do like the looks of them.

    does anyone know if 24 spokes radially laced is sufficient for my weight?


    Quote Originally Posted by Racer Ex View Post
    I have it. No chain whip is nice. At least that's what my knuckles say .
    longer lever on the chain whip, gets you further away from the spokes.

    Quote Originally Posted by Racer Ex View Post
    Don't know why they didn't go to a coarser thread on these things; dirt track motorcycles have a similar set up with a knock off nut and the TPI count is really low...dirty environment and no issues.
    I guess the idea is that they are always covered (the threads on the hub). When I change cogs I put a little of anti-seize (that white gunky stuff that is impossible to wash off your hands/clothes).

    I once worked in manufacturing on an internship, higher TPI was always used, especially in a situation where you had to torque something down (diaphragm compressors). You have more control with a fewer TPI. One revolution of the nut (or in this case, cog) gives you a smaller lateral movement. Also with more teeth in the thread the torque is spread out over them all and you have more teeth that "bite"

    ^just my 2 cents. from an engineering standpoint.

    one thing I don't like is that there are different metals in contact. for example steel cogs on aluminum hubs. The cog is harder than the hub so there is potential to strip the threads or cross thread. (either way I was taught to apply anti-seize when two different metals are in contact, because they cant spur a corrosion seizing them together.

  7. #182
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dro.pru View Post
    ...
    My only concern is the radial laced front wheel. I've always been wary about it in general (Nothing like a classically laced wheel in terms of strength). Even more so since I'm a heavier rider (200 lbs). That being said I do like the looks of them.

    does anyone know if 24 spokes radially laced is sufficient for my weight?
    ...
    I've got this wheelset. The spokes are burly 14 gauge. The wheelset is strong (and heavy). I'm about the same weight as you. It'll work.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  8. #183
    Member
    Join Date
    Dec 2013
    Location
    NJ
    My Bikes
    Windsor Hour Track Frame, Motobecane Cafe Fixed, Gravity Road Bike
    Posts
    41
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Brian Ratliff View Post
    I've got this wheelset. The spokes are burly 14 gauge. The wheelset is strong (and heavy). I'm about the same weight as you. It'll work.
    Thanks! Settled any concern I had. (Now i jut need my christmas bonus money. )

  9. #184
    Resident Alien Racer Ex's Avatar
    Join Date
    Jul 2007
    Location
    Let me check.
    My Bikes
    Of course.
    Posts
    11,238
    Mentioned
    14 Post(s)
    Tagged
    1 Thread(s)
    Understand the theory of thread pitch. And in some applications fine thread is just fine.

    The problem with an engineering theory is that it has to go out into the real world. Any greater "bite" on a finer TPI goes away badly if those threads are compromised in any way through either dirt, cross threading (more likely on fine TPI in a rushed situation or with less adept mechanics) or corrosion (anti seize isn't 100% protective, and is a nice dirt attractant, but it's probably better than bare threads).

    You look at the vast majority of race related wheel or drive train "quick change" items (motorcycles, Indy cars, Sprint cars, Etc) and you'll see a lot of low TPI stuff for that reason. I've yet to see anyone use a torque wrench on a cog or lock ring

    Nice shot of an early Indy car quick change hub:



    The rotary wing combat aircraft I worked on used primarily fine pitch threads, I assume on the engineering premise you noted because virtually every fitting was torqued. We had big trays of replacement nuts and bolts for things that were on and off on a regular basis (pre-flight and low period inspection), even with well trained mechanics, torque wrenches and a relatively clean flight line (unless we were out in the field) we had a lot of stripped stuff.

    Noteworthy that the race hub above uses the lugs to take up the torque load and the knock off "just" takes side load. Puzzling that we don't have splined hubs by now instead of the half step of screw on splined carriers. How long has road had splined freehubs instead of screw on freewheels? We can have a bunch of different BB standards hitting track bikes yet have zero progress here.

  10. #185
    Senior Member
    Join Date
    Jan 2006
    Location
    Australia
    Posts
    1,446
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dro.pru View Post
    yeah, thanks for that other source. I have to see how much is the shipping, if i have to spend whatever I save on the wheels then it is not worth it.
    Ribble do have free shipping over a certain amount to Australia (bought from them quite a few times - also have nicely prices Dura ace cogs ). Even if you don't get charged shipping, you may get slugged duty on the goods when they land in the States. Not sure of your import laws, currently in Australia we can get items $1000 and under duty free. Helps that our dollar is strong at the moment...
    http://climbinglama.blogspot.com.au

  11. #186
    Member
    Join Date
    Dec 2013
    Location
    NJ
    My Bikes
    Windsor Hour Track Frame, Motobecane Cafe Fixed, Gravity Road Bike
    Posts
    41
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    dalai, the set i'm currently looking at isn't in stock but once it is i imagine that i'll order it from there.

    Racer ex, it's nice to have a different perspective on things so thanks for that.

    Changing cogs/lockrings is like shaving, do it in a rush and you'll mess up and cut yourself.

  12. #187
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    RE: cog threads...

    The way I see it, a threaded system is the only way to achieve a zero backlash interface while ensuring the two parts are reasonably easy to disassemble. More importantly is you don't have to be all that accurate with your thread cutting to achieve that zero backlash interface. The knock against splined systems is they all inherently have backlash built into their design. With a road freewheel, backlash is acceptable since torque is applied to the hub in only one direction. To make a guaranteed low backlash spline means being really accurate with the machining, which means more expense. Miche cuts corners a little with the machined tooth profile they use. White Industries cogs are simply more expensive than their threaded cousins of equivilent (or better) quality.

    The Miche and White Industries both have proprietary splined cog systems; White Industries skip the carrier and have a proprietary hub to which these cogs mount. Easton track wheels use a nonproprietary splined system (Shimano cassette standard) and no carrier. Truth be told, having a true zero backlash system is probably overrated, but track racers tend to be picky about these things.

    On the point about the fine pitch, I think it's a combination of tradition dating back to steel hubs, standards, and concern about back pressure unscrewing the cog. Fine thread pitch means the cog will take more force to loosen and once loosened, will put less stress on the lockring under back pressure.
    Last edited by Brian Ratliff; 12-23-13 at 08:02 AM.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  13. #188
    Resident Alien Racer Ex's Avatar
    Join Date
    Jul 2007
    Location
    Let me check.
    My Bikes
    Of course.
    Posts
    11,238
    Mentioned
    14 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Brian Ratliff View Post
    RE: cog threads...

    The way I see it, a threaded system is the only way to achieve a zero backlash interface while ensuring the two parts are reasonably easy to disassemble...Truth be told, having a true zero backlash system is probably overrated, but track racers tend to be picky about these things.
    Having watched a few hundred threaded cog changes I'd say "reasonably easy" is relative. Especially at the Superdrome in the summer when all those nice bits that were assembled in air conditioned shops expand.

    Quick change Indy car hub above compared to a track bicycle...700HP + 4g's of braking force and 1800 lbs stop/starting feeding through a giant contact patch and multiple G's of side load on top of everything else changed out in 10 seconds (plus a hub temp that varies several hundred degrees) ...vs 1.5 HP, 260 lbs if it's a typical chubby sprinter and probably .03 G's of stopping force and changed out in 5-7 minutes.

    Yep, those concerns about backlash might be overrated

    But if that was keeping people up at night (and it shouldn't be given the above and that the other spline systems seem to work just fine with potential backlash) it would be quite easy to machine a slight taper at the base of whatever spline system you developed which would create a zero backlash interface. Same premise as a one bolt crank only much less aggressive taper.

    Badda bing, badda boom.

    Waste of CNC time though.

  14. #189
    Senior Member
    Join Date
    Jan 2009
    Location
    NZ
    My Bikes
    More than 1, but, less than S-1
    Posts
    3,368
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Racer Ex View Post
    Having watched a few hundred threaded cog changes I'd say "reasonably easy" is relative. Especially at the Superdrome in the summer when all those nice bits that were assembled in air conditioned shops expand.

    Quick change Indy car hub above compared to a track bicycle...700HP + 4g's of braking force and 1800 lbs stop/starting feeding through a giant contact patch and multiple G's of side load on top of everything else changed out in 10 seconds (plus a hub temp that varies several hundred degrees) ...vs 1.5 HP, 260 lbs if it's a typical chubby sprinter and probably .03 G's of stopping force and changed out in 5-7 minutes.

    Yep, those concerns about backlash might be overrated

    But if that was keeping people up at night (and it shouldn't be given the above and that the other spline systems seem to work just fine with potential backlash) it would be quite easy to machine a slight taper at the base of whatever spline system you developed which would create a zero backlash interface. Same premise as a one bolt crank only much less aggressive taper.

    Badda bing, badda boom.

    Waste of CNC time though.
    Why hasn't the White Industries system taken off? (Besides adoption by Saris)
    Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.

  15. #190
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Racer Ex View Post
    ...
    Yep, those concerns about backlash might be overrated

    But if that was keeping people up at night (and it shouldn't be given the above and that the other spline systems seem to work just fine with potential backlash) it would be quite easy to machine a slight taper at the base of whatever spline system you developed which would create a zero backlash interface. Same premise as a one bolt crank only much less aggressive taper.
    ...
    No arguments with that. These are all good reasons to go to splined systems. The only reason I don't is because of the proprietary, single source nature of the splined cogs and the availability of very good threaded cogs. For instance, my teammate found a 13 tooth NOS Campy aluminum cog which is the smoothest running cog I've ever seen/heard. Those little discoveries from back when track racing was more popular aren't possible if you are on a proprietary standard.

    On an off note, I've been surprised the steps people go through to dress up their cogs. Not only tumbling and/or polishing, but sourcing anti-friction coatings that will last only 5-6 races, etc.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  16. #191
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bigfred View Post
    Why hasn't the White Industries system taken off? (Besides adoption by Saris)
    Possibly because it requires a $200 proprietary hub. I get that on a race wheel. But I need a good supply of cheap hubs for training wheels (Miche hubs work great for this).

    It's not enough to have a better product (usually). One needs a path to transition from the current state of the art to the new solution. For instance, Mavic track disc users would scream bloody murder if Mavic adopted the WI standard exclusively, and if they tried to sell the WI standard alongside the threaded standard, nobody would buy the WI equipped disc. Now, if WI modified their spline to work with a carrier and offered a 13 tooth cog (useful for sprinting), and then went out and got Shimano to offer cogs with their spline, then it might develop into a standard. But I'm not sure if you can get a splined interface on a 13 tooth cog and carrier (not much room between the teeth and the carrier - Miche bottoms out at 14 tooth).
    Last edited by Brian Ratliff; 12-23-13 at 12:08 PM.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  17. #192
    Senior Member
    Join Date
    Jan 2009
    Location
    NZ
    My Bikes
    More than 1, but, less than S-1
    Posts
    3,368
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Brian Ratliff View Post
    .... But I need a good supply of cheap hubs for training wheels (Miche hubs work great for this)....
    How many hubs are you wearing out on the track?

    Quote Originally Posted by Brian Ratliff View Post
    ...Now, if WI modified their spline to work with a carrier and offered a 13 tooth cog (useful for sprinting), and then went out and got Shimano to offer cogs with their spline, then it might develop into a standard. But I'm not sure if you can get a splined interface on a 13 tooth cog and carrier (not much room between the teeth and the carrier - Miche bottoms out at 14 tooth).
    I believe the 13 tooth cog is going to preclude most solutions that screw on over the existing threaded design.
    Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.

  18. #193
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bigfred View Post
    How many hubs are you wearing out on the track?
    I have four track wheelsets, two clincher and two tubular including a set of race wheels. Three of those have Miche hubs; the race wheelset has Phil Wood. The normal solution for the problem of changing cogs is just adding wheelsets!

    I do a lot of training on the road, since track time is at a premium. In any case, having to buy a $200 rear hub for each wheelset would just about double the cost of the wheelset. And since WI doesn't have a fixed-fixed option, I'd actually be changing cogs much more frequently than my present system. At the track, I'll have two wheelsets with three or four cog options which with chainrings cover the entire span of gear ranges from warmup to overgear. On the road, I'll have two cog options, a warmup gear and an effort gear.

    I really only change cogs very rarely and mostly for the road training to take into account varied terrain.

    I believe the 13 tooth cog is going to preclude most solutions that screw on over the existing threaded design.
    Probably right.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  19. #194
    Senior Member
    Join Date
    Jan 2009
    Location
    NZ
    My Bikes
    More than 1, but, less than S-1
    Posts
    3,368
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Brian Ratliff View Post
    I have four track wheelsets, two clincher and two tubular including a set of race wheels. Three of those have Miche hubs; the race wheelset has Phil Wood. The normal solution for the problem of changing cogs is just adding wheelsets!

    I do a lot of training on the road, since track time is at a premium. In any case, having to buy a $200 rear hub for each wheelset would just about double the cost of the wheelset. And since WI doesn't have a fixed-fixed option, I'd actually be changing cogs much more frequently than my present system. At the track, I'll have two wheelsets with three or four cog options which with chainrings cover the entire span of gear ranges from warmup to overgear. On the road, I'll have two cog options, a warmup gear and an effort gear.

    I really only change cogs very rarely and mostly for the road training to take into account varied terrain.



    Probably right.

    I see where you're at. But, the point of adopting a splined knockoff design is to ease cog changes and make the requirement of multiple rear wheels redudant. No more chain whips and torque tightened cogs. Just a retaining ring, which would experience zero torque and require only enough tightening to keep from backing off.
    Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.

  20. #195
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bigfred View Post
    I see where you're at. But, the point of adopting a splined knockoff design is to ease cog changes and make the requirement of multiple rear wheels redudant. No more chain whips and torque tightened cogs. Just a retaining ring, which would experience zero torque and require only enough tightening to keep from backing off.
    I get that. But then I'd be worried about cross threading lockrings instead of cross threading cogs. And if the wheels are tubular, it is always useful to have an extra wheelset lying around on race day anyway.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  21. #196
    Senior Member
    Join Date
    Jan 2009
    Location
    NZ
    My Bikes
    More than 1, but, less than S-1
    Posts
    3,368
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Brian Ratliff View Post
    .. But then I'd be worried about cross threading lockrings instead of cross threading cogs....
    Hence, Ex's point about corser thread pitches for a lockring that will see limited if any lateral load and zero torque load. With a splined hub/cog interface you no longer require a thread pitch so fine that you have to worry about cross threading.

    A positive design spiral of sorts.
    Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.

  22. #197
    Resident Alien Racer Ex's Avatar
    Join Date
    Jul 2007
    Location
    Let me check.
    My Bikes
    Of course.
    Posts
    11,238
    Mentioned
    14 Post(s)
    Tagged
    1 Thread(s)
    Damn discs kill off a splined hub system for most folks. That's why I'm on the Miche adapter.

    The 13 cog with a coating is kind of a reach if the papers I've read about friction losses on smaller radius gears with a chain is accurate. Not sure if folks confuse quiet with fast too. I can make a drive train that will be dead silent and suck power like crazy.

    You'd figure if the chain line is right the friction from a cog is tiny, essentially the only "slip" you have is the fractional point of engagement and disengagement. Couple of milleseconds? If it's side loaded you're still not talking about a large event.

    Big ass gears. Less RPM, less frictional loss.

    Interesting discussion.

  23. #198
    Senior Member
    Join Date
    Aug 2012
    Location
    Twin Cities, MN
    Posts
    347
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Just wondering what kind of intervals you track cyclists use? Pyramid? Tabata?

  24. #199
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Racer Ex View Post
    Damn discs kill off a splined hub system for most folks. That's why I'm on the Miche adapter.

    The 13 cog with a coating is kind of a reach if the papers I've read about friction losses on smaller radius gears with a chain is accurate. Not sure if folks confuse quiet with fast too. I can make a drive train that will be dead silent and suck power like crazy.

    You'd figure if the chain line is right the friction from a cog is tiny, essentially the only "slip" you have is the fractional point of engagement and disengagement. Couple of milleseconds? If it's side loaded you're still not talking about a large event.

    Big ass gears. Less RPM, less frictional loss.

    Interesting discussion.
    1+ to almost everything. The only exception I have is to the drivetrain noise. Noise energy is losses. You can coat the cog/chain in rubber or something and make it silent and dissipate the losses into heat, but all things being equal, a quiet drivetrain is less lossy than a loud one. But to get back to the point about differences in cog tooth profile: the cog tooth is an involute, meaning ideally there is no point where the chain roller is in sliding contact with the cog. Ideally, you cut a cog using a hobbing process which makes the involute shape nearly exactly. Less expensive cogs use an approximate shape programmed into a CNC machine tool. The really cheap cogs are stamped. But getting back to the point about noise; some or all of this noise from cog engagement is from non-ideal sliding contact with the chain.

    But all this is getting more into the mental aspects of the sport than physics. People want things quiet because they sound more efficient, which puts them in a better state of concentration for the event. It's one of the things I've grown to enjoy about track. Everything's so simple and elegant about the equipment that competition really is stripped down to its basics. The losses in the drivetrain really are very small (unless you put your chain too tight!).
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

  25. #200
    Senior Member Brian Ratliff's Avatar
    Join Date
    May 2002
    Location
    Near Portland, OR
    My Bikes
    Three road bikes. Two track bikes.
    Posts
    9,477
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by sbs z31 View Post
    Just wondering what kind of intervals you track cyclists use? Pyramid? Tabata?
    For sprint: all out for 100-1000m (depending on what you are working on). Stagger to your chair. Some people choose to puke at this point (they'll usually visit the storm drain prior to sitting. Usually). Sit for 15-20 minutes. x5. Give or take.

    There's a variety of other drills, but pretty much everything is done at an intensity way harder than your average roadie has ever experienced, for a much shorter time, with a lot longer rest.

    For enduro: they road race. More or less.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

Page 8 of 49 FirstFirst ... 67891018 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •