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Thread: Birdy thread

  1. #26
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    Couldn't agree more about the virtues and joy of a Birdy. Had mine for nearly a year and I'm now looking to upgrade parts to make it absolutely sensational!

  2. #27
    jur
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    Birdy Monocoque Review

    Model: Alivio
    In Australia, the new Birdy monocoque frame range is still presented along the older scheme where color denotes model. More frame colors are actually available from Pacific Cycles but the size of the local market is quite small so this is probably not a bad business decision. The downside is it does stick you with a color that you might not like.

    I decided to buy the entry-level bike since I like to change the componentry to what I want. The rationale is that the cheaper installed bits don't result in a big loss when upgrading them to exactly what I want. This meant the cream-colored 8sp Alivio model. They also have a black Rohloff and a deep blue 24sp Shimano Intego, and a brushed silver 9sp LX. The difference between the LX model and the Alivio is mostly limited to a different model Velo saddle (who cares if that's to be replaced anyway) and different derailer plus one more gear. Other bits are I think much the same. So the Alivio model presents a significant price advantage if the only real difference is a rear derailer, one less gear and the gear shifter - less than $100 cost all up, whereas the selling price difference is $450 or so. It's easy to see the economic sense in the Alivio - even if you upgraded it all to the same level as the LX, you'd still end up way in front.

    You can find this model in the Pacific 2008 pdf catalog line-up; the local importer (St Kilda Cycles) orders just one color from each model range to limit stock.

    Presentation/looks
    Color: Metallic cream frame, with mostly black anodised componentry
    In my case, originally I wasn't very enthusiatic about the cream color. Up close though, it is very nice indeed - it is the same metallic cream/off-white some cars are done up in these days, very striking, like a pearl. The black componentry shows up well against the cream frame. But so does every little speck of dirt.

    The flowing lines of the monocoque frame is a significant departure from the agricultural looks of the first generation frame. The forks are unchanged, but the fork above anything else is what defines the looks of the Birdy - weird-looking? sure; agricultural? bl**dy oath; but it is a bit like the bike's badge - it defines it, it is unique to the Birdy. Bottom line is, it's a Birdy and that fork is as much a part of the package as the stylish Birdy logo.

    On the front of the head tube you'll find Pacific Cycles' logo.

    Suspension:
    On to riding. This is where the Birdy excels, where the weird-looking fork is fully justified. I have the tyres pumped to the maximum of 90psi. The traction on gravel surfaces sucked but I was more interested in feeling the detailed effect of the full suspension rather than the tyre plushness.

    I was not disappointed. Riding over rough surface is very good indeed - you are aware that you are riding over bumps but they totally lose any harshness or jarring they would otherwise have. Taking corners at speed is improved since road holding over rough surface is better, as dangerous bouncing is eliminated. The suspension imparts almost exactly the same feel as soft Big Apple tyres. It is debatable whether a rigid frame with soft Big Apples isn't a better alternative; but with the Birdy you have the option of installing fast tyres such as the Stelvio or Kojak but still have the benefit of the soft ride.

    The Birdy fork has a leading link suspension, meaning the moving link is in front, ie leads, the rigid fork member. (The Pacific Reach forks are a trailing link suspension.) The leading link curves up and comes back together over the wheel where the damped spring is located. The wheel is mounted on the leading link.

    I can see the leading link vibrating rapidly with the road surface bumps when riding along. I haven't seen this movement on any other bike, probably because the range of motion is amplified by the lever arm length at the spring. This movement is a great visual feedback of the forks absorbing road vibration.

    Pedalling rapidly with cadence > 100rpm, I noticed some minor bouncing of the rear elastomer. I might get the stiffer green elastomer in case I do fast road rides. The red is just right for normal sort of riding. Replacing the elastomer is dead simple requiring no tools - just pull it off with the rear swingarm latch unhooked, and push on the other one, a 10s job; you can carry the spare elastomer with you in the saddle bag and swap it at any time during any ride. In any case it would probably be a big help in trying to develop a very smooth pedalling style.

    Steering/handling:
    The steering responsiveness (often called twitchiness) is not what I expected. Small wheels due to their low mass and small size have low angular moment around the steering axis, and this, as well as the steering geometry and tyre profile, is responsible for a small wheeler's light, responsive steering. Not so the Birdy. It feels much more like a large-wheeled bike. Part of the explanation is that the steering assembly's metalworks are "far away" from the steering axis, and there is quite a lot of it, so the angular moment is increased over a simple fork. From examining the geometry (see later) the trail is also large, resulting in "heavier" steering. I'm not seeing this as a plus or a minus - it is just different.

    The Birdy cannot be ridden hands-off *at all*. I haven't read about others' experience in this regard; but when I took my hands off the bars going at a reasonably fast speed, the front developed *instant* and violent shimmy. There is mention in the Australian manual that if there is shimmy while riding hands-on, the front suspension pivots have to be tightened, but that is not my case - the pivots are positively tight. No, this is plain hands-off shimmy as most bikes will develop under the right conditions. I have studied this phenomenon in some detail and all I can say is the Birdy is a very bad case. Riding at low speed where shimmy doesn't develop, resulted in the bike veering all over, completely uncontrollable. So no hands-off riding ever, period. Further discussion for the reason is under the Geometry heading.

    The above does not impact on normal riding - I found the Birdy as stable and easily controllable as any other bike.

    At this stage due to not having any other tyres to try, I can't say how much of the steering performance is due to tyre profile.

    Gearing:
    The 8sp gearing ranges from 30" to 87". Low end is adequate but I am used to higher gearing at the top end. For average riding it is adequate. I have a spare Schlumpf Speed Drive and may install this at a later date; time will tell.

    The level is Alivio and I find it works quite as well as the XT stuff I have on the Swift and Yeah, albeit a bit louder. I may leave it at 8 speed as chains are cheap and I can have a couple of spare chains ready to swap to extend cassette life.

    Braking:
    The braking isn't stellar but it is adequate. At this stage I am blaming the pad quality; I use higher quality pads and expect braking to improve once I replace the pads with better ones. The pad adjustment may also be out. I had to re-set the rear pads after removing the back wheel (see Little Things) and they seem much better. But since I have developed the habit of not using the back brakes unless I really *have* to, the front brakes have to be perfect.

    Braking from the leading link has the effect that the suspension is stretched open when braking. This works against the weight resting heavily on the front during braking, so there is very little, if any, diving during braking, unlike a telescopic suspension which can dive deeply when braking hard. Pacific Cycles make a point of this but don't say why this is good. I can think of 2 reasons: that during sudden sharp braking you don't have a sudden unexpected weight shift forwards, and also that during sustained braking, the suspension travel and operation is largely unaffected.

    Comparative Geometry - Birdy vs Swift [all dimensions in mm]:
    Wheelbase: 1010 vs 1030 (longer is better?)
    Effective top tube: 585 vs 550 (longer is better for taller riders)
    Head angle: 71 vs 72
    Seat angle: 73 vs 72
    Trail: 63 vs 36
    BB height: 290 both (depends on tyre width)
    Stepover height: 535 vs 640
    Chainstay length: 430 vs 410
    Head tube length: 88 vs 125
    rear dropout: 135 both

    The Birdy's wheel flop factor is quite strong, resulting from a slack head angle and lots of mass in front of (and therefore above) the steering axis, partially due to the sports stem. So the front wheel has quite a strong tendency to flop sideways. The flop is not dependent on speed - it wants to happen at any speed.

    The Birdy also has quite a large trail; ie the wheel contact point is behind the steering axis, like in a shopping trolley wheel. So at speed, the trail tends to straighten the wheel out - the faster, the more you get. This ought to make the bike very ridable hands-off.

    So with trail and flop you have these opposing forces, one of which is speed dependent - the wheel flop factor steers away from the middle at any speed, while the trail steers to the middle at highish speeds. At low speed, the flop factor is stronger than the trail, so the bike veers off. At high speed, the trail is stronger than the flop, but now there is over-correction from any disturbance so the bike now veers in the opposite direction, and back again, and so on, resulting in shimmy at high speed. Possibly the comfort stem which is further backwards may be more stable.

    The Swift, which also can't be ridden hands-off for long stretches, has not exhibited any tendency to shimmy under similar conditions.

    The slightly steeper seat tube angle has the effect that as the seatpost is set higher, the saddle has to be set back further to end up in the same spot as for the Swift.

    Fitment:
    Most of my other folding bikes have a 55cm effective top tube. This is logical as it corresponds to a medium sized bike, and makers obviously want their bikes to fit as many customers as possible. However, the Birdy has a 58.5cm effective top tube, so it caters for slightly taller riders which is great since I am on the edge of being too tall for a size medium.

    I like a more forward body posture, arms and body roughly at 45 from vertical. I use the Peter White approach to fitting, and this has the result that all my bikes end up being very similar in fit - the relative position of saddle, pedals and handlebars are the same on all bikes. The preferred fit has resulted in the Birdy saddle going back as far as it can go; the sport stempost places the handlebars smack in the right spot. The lowest setting results in the handlebars at saddle level. So the Birdy fits me with no mods. The slightly longer effective top tube, plus that there is a lot of seatpost left over for extension, makes the Birdy suitable for taller riders as well. (I am average at 5'10".) Pacific Cycles claims to 6'4" and 110kg, including luggage. I think that claim has substance.

    Folding:
    The Birdy back end folds along similar lines to the Brompton, but where the Brompton wheel ends up directly below the top tube necessitating that characteristic hump, the Birdy's rear swingarm rotates slightly sideways so the back wheel ends up just to the left of the top tube, allowing freedom of top tube design. The seatpost locks the back in place. The handlebars fold on the other side of the frame as the front wheel, effectively holding it in place, so it is a nice package when folded without bits swinging everywhere when trying to carry it. The 2 wheels and seatpost form a balanced tripod so it stands when folded.

    I will need lots of practise to get it down to the sub-15s what I routinely do on the Yeah. For one thing, I have to figure out what to do with the crank arms, what the most optimum position is. I have tried to follow the (excellent Australian) manual's directions, but that didn't seem to help. I will just have to work out the best one for myself like I did on the Yeah. Part of the problem is the cranks move when folding so they don't end up where you think.

    The front wheel folding is straightforward but also needs practise to get it smooth. I will need to optimise the position of the securing screw that holds the wheel in folded position - it seems too tight.

    The front wheel assembly is rotated outwards to fold and rotated back in after the rear swingarm is folded. It stops against the rear derailer and sticks out rather far - another reason for looking at slimming down the derailer. A low profile XT Shadow might be a great choice; I have one on the Swift and might put the planned Ultegra on the Swift instead. The front hub is narrow-flanged and that also makes the folded size a little narrower.

    Engineering/quality

    General: The Birdy is a very well thought out design. From the standard equipment to the folding details to the optional equipment, everything just works. The build quality is good too; there are no blemishes, the welds are as good as these can get, the wheels are true and everything is straight. Seatpost doesn't slip and has handy laser-marked height indicators.

    Cabling: The cables are routed internally lending a clean uncluttered look. The RD cable is pulled out to the rear when folding, and pushes back through to the front when unfolding. A frame screw that sticks out to the side promotes the pushing back of the cable; if the cable is located too wide, outside the reach of this screw, the cable may not be pushed back in properly and you get this large loop of cable that you have to push back manually. This happened to me the first time before I knew what that screw was for. That screw looks like an afterthought. When unfolding, you get this scraping sound and it took me a while to trace where it was coming from - it's that cable getting pushed back.

    Stempost hinge: The stempost hinge just oozes Teutonic quality. I disassembled mine to replace the upper half of the stempost with the sports version. The hinge parts are machined from solid aluminium. The upper and lower hinge halves are identical so only one piece has to be mass-produced, and therefore they fit together as perfectly as manufacturing tolerances allow. Thin washers furnish rotating bearing surfaces. The hinge jaws have a tapered lip over which a matching V-shaped channel fits to clamp them together. The lever - also machined from solid - which operates the mechanism, folds flat against the hinge face, unlike the older design where the lever sticks straight up. The steel hinge axle has an eccentric portion for operating a rod going to the V-clamp at the front. There is one screw for adjusting clamp tension which is double positively retained - a lock nut plus the lock nut itself is a nylock. No chance of that combo working loose, ever. One screw adjusts the hinge bearing preload and 2 screws hold the lever in place on the axle. All those screws are fixed in place with blue Loctite. I think spring washers or something similar would be better. But those screws will not result in a loose hinge when unscrewing. When the hinge is closed there is zero detectable play. It is miles and miles in front of the Dahon hinge. Probably costs more as well - but for such a safety critical part there must be no skimping in design and quality.

    Installed equipment:

    Stempost: sport version, but originally it came with the comfort version. It is height adjustable with a brass button locking into holes which keeps the alignment right and is a safety backup in case the QR is loose.
    Brake levers: Avid FR5; these are my favourite - light weight, good looks and low cost.
    Brakes: Avid Single Digit 5 V-brakes
    Rims: Alex DV15, 24 spoke
    Rear Hub: Shimano Parallax 32 hole (laced to 24h rim), 3x lacing
    Front hub: Birdy special with radial lacing; I like the look of this hub. It breathes quality. It is a narrow flange
    hub to clear the fork members, with axle spacers to make it 100mm wide.
    Tyres: Maxxis Birdy 355x37 with Kevlar puncture protection
    Velo comfort saddle
    Alivio 8sp gearing

    Optional equipment:

    Mudguards: I opted for permanently installed mudguards as Melbourne gets rain all year round. The installation instructions that came with them (produced by the original Australian importers) are as good as they get. Pity the supplied parts no longer exactly match the description. I had to mess around a bit to figure out exactly what went where. And I had a few screws left over afterwards.

    The mudguards provide good coverage. The back one has a protective strip that it rests on when folded.

    Rear rack: For general and commuting duty I got the folding Mono rack. Another quality item with exactly matching parts and bushes at the swivelling members.

    The top mounting position is just forwards of the seatpost under the older frame's seatpost clamp. This caused problems with slipping seatposts so the new frame has a conventional clamp instead. Weirdly, I was supplied no mounting screw for this position.

    The bottom mounting point is at the top of the swingarm. I had to remove the powder coating on the holes to allow the tightly-fitting bushes to go in.

    Front lowrider racks: This is stock standard and easy to install. Nothing special to report except that they are very nicely thought out, as usual.

    torsional/twist test:
    This is one stiff frame. I do detect some flex in the handlepost and handlebar assembly when pulling sideways hard, but it is less than I expected. The monocogue frame's shape gives a lot of extra stiffness.

    Annoying Little Things:

    I can't remove the back wheel. Unhooking the brake noodle releases the brake arms but the acute angle of the pads with arms means one end of the pads move away from the rim much less than the other end, and it's just not enough. So to remove the back wheel I either have to deflate the tyre or undo a brake pad. Both options suck. Pumping the tyre afterwards maybe sucks less. The quick release acorn nut also snags on the derailer so that also has to be removed to remove the wheel. Hardly quick release.

    Unhooking the front brake noodle is fiddly because it is upside down, interfering with itself.

    No bottle cage fittings! What is it with so many folding bike makers - do they think riders don't need to drink?? I have a tool for installing rivnuts and have previously installed some on my Yeah with good success. The Birdy top tube may also get a pair but I will need to get expert advice on this.

    The seat post is not long enough to form a balanced tripod with the mudguards installed, so it falls over. I will have to make an extension for it.

    The new monocoque frame has less freedom for carrying the frame; the only handy place is in the triangle in front of the seat tube. The package is less balanced and the Birdy angles down when carrying it, but the strain on the hand is still OK.

    The handlebars when folding down snag against the rear axle. It would be better if it can go past that point; I can do this by pushing the adjustable stempost all the way in but that is an extra folding step I'd like to avoid.

    The cables at the handlebars are not great - I will have to neaten them up a bit. At the moment they are of unequal length.

    Dirt isn't cream-colored - it is at the opposite end of the spectrum. The nice cream paint shows off every speck of dirt with great clarity.

    Overall performance:
    Is it as fast as my Swift? Not even close. But the Swift is way lighter, has better gearing and has speedy tyres installed, so hardly a fair comparison.
    How about against the Yeah? I have been commuting with the Yeah for a few months now. Well, the Yeah's Primo Comets are faster, and it has ultra-wide gearing, so again not a good comparison. The Birdy as is, is perhaps 5% slower than the Yeah. But it is a whole lot nicer to ride due to the suspension. Then again, the Yeah cost me $100 (before upgrades) not $1530 (before upgrades).
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  3. #28
    crazy bike girl msincredible's Avatar
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    I can ride for a few seconds no-handed on my Birdy. Haven't dared to try longer but I've never seen the shimmy.
    Countries I've ridden in: US, Canada, Ireland, UK, Germany, Netherlands, France, China, Singapore, Malaysia
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  4. #29
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    Jur
    Congratulations on your new Birdy and a very thorough review. I am jealous of your monocoque frame. It looks great!

    Here are a couple of thoughts from my Birdy experience.

    Water Bottle

    What works really well for me is a Cat Eye plastic bottle cage zip tied to the stem riser. http://www.mec.ca/Products/product_d...=1223437007264

    I had first tried mounting the bottle on top of the top tube but did not like the way the water sloshed backwards and forwards when the bottle was half empty.

    Tires

    When I replaced the old style Birdy tires with Schwalbe Marathon Racers it made a huge improvement in the way the bike felt (faster smoother and higher quality). Your tires are probably better than the old Birdy tires but I think that you would still find Marathon Racers or Stelvios a very worthwhile upgrade.

    David

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    Quote Originally Posted by msincredible View Post
    I can ride for a few seconds no-handed on my Birdy. Haven't dared to try longer but I've never seen the shimmy.
    I'm not comfortable riding no hands but I find that I only need a finger tip on the bars to feel secure.

    Shimmy has not been a problem for me and I've only felt it once or twice under unusual conditions (at speed with a heavy load loaded way back on a rack attached to the suspended rear arm)

    David

  6. #31
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    Quote Originally Posted by jur View Post


    I will need lots of practise to get it down to the sub-15s what I routinely do on the Yeah. For one thing, I have to figure out what to do with the crank arms, what the most optimum position is. I have tried to follow the (excellent Australian) manual's directions, but that didn't seem to help. I will just have to work out the best one for myself like I did on the Yeah. Part of the problem is the cranks move when folding so they don't end up where you think.
    I've always liked this video and try to emulate his procedure ... he cuts it under 10 sec..

    http://www.kinetics.org.uk/assets/mu.../birdfold.mpeg

  7. #32
    Part-time epistemologist invisiblehand's Avatar
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    Quote Originally Posted by jur View Post
    Comparative Geometry - Birdy vs Swift [all dimensions in mm]:
    Wheelbase: 1010 vs 1030 (longer is better?)
    Effective top tube: 585 vs 550 (longer is better for taller riders)
    Head angle: 71 vs 72
    Seat angle: 73 vs 72
    Trail: 63 vs 36
    BB height: 290 both (depends on tyre width)
    Stepover height: 535 vs 640
    Chainstay length: 430 vs 410
    Head tube length: 88 vs 125
    rear dropout: 135 both

    The Birdy's wheel flop factor is quite strong, resulting from a slack head angle and lots of mass in front of (and therefore above) the steering axis, partially due to the sports stem. So the front wheel has quite a strong tendency to flop sideways. The flop is not dependent on speed - it wants to happen at any speed.

    The Birdy also has quite a large trail; ie the wheel contact point is behind the steering axis, like in a shopping trolley wheel. So at speed, the trail tends to straighten the wheel out - the faster, the more you get. This ought to make the bike very ridable hands-off.

    So with trail and flop you have these opposing forces, one of which is speed dependent - the wheel flop factor steers away from the middle at any speed, while the trail steers to the middle at highish speeds. At low speed, the flop factor is stronger than the trail, so the bike veers off. At high speed, the trail is stronger than the flop, but now there is over-correction from any disturbance so the bike now veers in the opposite direction, and back again, and so on, resulting in shimmy at high speed. Possibly the comfort stem which is further backwards may be more stable.

    The Swift, which also can't be ridden hands-off for long stretches, has not exhibited any tendency to shimmy under similar conditions.

    The slightly steeper seat tube angle has the effect that as the seatpost is set higher, the saddle has to be set back further to end up in the same spot as for the Swift.

    Fitment:
    Most of my other folding bikes have a 55cm effective top tube. This is logical as it corresponds to a medium sized bike, and makers obviously want their bikes to fit as many customers as possible. However, the Birdy has a 58.5cm effective top tube, so it caters for slightly taller riders which is great since I am on the edge of being too tall for a size medium.

    I like a more forward body posture, arms and body roughly at 45 from vertical. I use the Peter White approach to fitting, and this has the result that all my bikes end up being very similar in fit - the relative position of saddle, pedals and handlebars are the same on all bikes. The preferred fit has resulted in the Birdy saddle going back as far as it can go; the sport stempost places the handlebars smack in the right spot. The lowest setting results in the handlebars at saddle level. So the Birdy fits me with no mods. The slightly longer effective top tube, plus that there is a lot of seatpost left over for extension, makes the Birdy suitable for taller riders as well. (I am average at 5'10".) Pacific Cycles claims to 6'4" and 110kg, including luggage. I think that claim has substance.
    So the effective top tube length is the horizontal distance between the seat post and saddle. Given you have the sport stem post, what is the effective stem length?

  8. #33
    Car free since 1995 pm124's Avatar
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    I think all Birdy bikes have hands off shimmy due to the folding mechanism, but thankfully no hands on shimmy.

    The difference between even the Marathon Racers and the Stelvios is night and day. I recently had to ride with a Racer on the back and was dropped by folks that don't usually drop me! The Birdy Maxis is even worse.

    Of course, nearly all of the performance difference between one bike and the next is due to the wheels and tires, at least on flat surfaces. The 24 spoke wheel with a relatively light rim is great. The Maxis is not so great, but gives a more confident ride.

    That is where I think the only real trade off comes in with a small wheeled bike. If you ride thin tires on small wheels, there is a danger that the wheel can sink into a pothole or grate.

  9. #34
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    I run Stelvios on my Birdy and have got two slow leaks over the past two months from potholes that I was not able to see or avoid in time. There definitely is a trade off when running skinny, high pressure tires on small wheels. I have since been only pumping the tires to 100 in the front and 110 in the back instead of the 120 maximum. We'll see if that helps any.

    In contrast, I have run over tons of stuff on my Dahon with Marathon Racers and have yet to get a flat. Speed wise, the Birdy is only slightly faster, maybe because the wheels are smaller and it is geared slightly lower? Of course, the ride on the Birdy is a lot smoother .

  10. #35
    Car free since 1995 pm124's Avatar
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    Jeffy--fun experiment. Do you have multiple average speed differences?

    Jur--I left out the most important comment. That is the most thoroughly detailed and well thought out review I have ever read. Hats off. You are an upstanding member of this online community. You are coming dangerously close to Sheldon Brown status.

  11. #36
    sundaycyclist
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    Thanks Jur again for the great rev.
    Here in Germany one can buy Birdy frame sets, one doesn't need to buy a complete bicycle if planning to make a big mod.

  12. #37
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    A thorough and readable report. These kinds of details are good to hear about. Congrats on your very nice new toy!

  13. #38
    SWS: Small Wheel Syndrome kb5ql's Avatar
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    I think I did about just under a mile no-handed the other day on the Bike Friday. The Birdy looks like fun. Thanks for the great write-up!!!

  14. #39
    jur
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    Quote Originally Posted by pm124 View Post
    You are coming dangerously close to Sheldon Brown status.
    Very kind, but dunno about that, you need a lifetime of experience to get there, not barely 4 years. You are getting dangerously close to being waaaaay too kind.
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  15. #40
    jur
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    Quote Originally Posted by invisiblehand View Post
    So the effective top tube length is the horizontal distance between the seat post and saddle. Given you have the sport stem post, what is the effective stem length?
    I have looked at the stempost and while I haven't actually taken a ruler to it, the effective stem length looks every bit as long as on the Swift, to my initial surprise.

    Further thinking about it made me realise that the seat tube is welded so it comes out behind the bottom bracket shell, so we are looking at apples and oranges. If the seat tube came out on the BB shell as in the Swift, the effective top tubes would be about the same for the 2! So we're back at the size medium.

    That explains why the effective stem looks to be about the same again. And why I couldn't ride it with the comfort stempost.

    Having said that, the sport stempost still offers taller riders who like a more sporty posture a roomier cockpit because the cockpit stretches if seat and handlebar are kept at the same height.
    Last edited by jur; 10-10-08 at 03:12 AM.
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  16. #41
    jur
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    To improve the gearing I installed the Vuelta 58T chainring I had lying around (after getting a 60T for the Swift). It improved the gearing to 31-91". Quite good for most riding. The nice thing is, the bigger ring is only about 1/2 tooth bigger in radius that the original, so it still fits nicely between the chain guards without sticking out. In fact it is now level instead of slightly recessed.

    The interesting thing is, the first time I went up a steep slope, the chain climbed off twice and wedged itself between guard and ring. It's a credit to the tough plastic that the guard didn't break right off. This happened twice and then never again. A bit of a puzzle. I blame a slightly dusty chain which had more friction to the teeth so instead of slipping into the tooth valley, the chain stuck on the tip and so climbed off.

    Checking last night I saw the chainline isn't centered on the middle of the cassette, making the line more acute in low gears, further strengthening my conclusion.

    After almost 2 weeks of commuting, I haven't changed any of my initial impressions. I would like some faster tyres but will probably first wear this set out.

    I have found by pulling the brake cable housing towards the back giving it more freedom, I am able to get the back wheel past the brake pads without having to deflate it.
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  17. #42
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    Quote Originally Posted by jur View Post
    I would like some faster tyres but will probably first wear this set out.

    I have found by pulling the brake cable housing towards the back giving it more freedom, I am able to get the back wheel past the brake pads without having to deflate it.
    I changed my tires out straight away and have kept the Birdy tires for emergency spares; one at home and one at work.

    The rear brakes are a bit of a PITA both because of clearance with the original pads and because its not practical to change to Koolstop pads as the clearance gets worse. I plan to eventually change the brakes to parallel action brakes (Magura, Avid, XT or LX) which should fix the problem.

    David

  18. #43
    jur
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    Both good ideas. Gives me a legitimate excuse to upgrade!
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  19. #44
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    Hi jur,

    I also wanted to add my congratulations!
    I can't wait to see the future mods...

    Barry
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  20. #45
    jur
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    Quote Originally Posted by pm124 View Post
    If the chain does not fall off when you fold it, you can put it in a low gear, but I wouldn't put it in the lowest, as it bends the chain quite a bit. I use an Ultegra medium cage. It doesn't gather as much chain as it should in part because road derailleurs have weaker springs than mountain derailleurs. The XT works great.
    When I checked the folding in lower gears, I found the chain gatherer hits the top tube. It might make it in next highest gear but it's already close in high.

    Quote Originally Posted by pm124 View Post
    Those tires are about -2-3MPH relative to the Stelvios, but are almost indestructible. In the US and Europe, Schwalbe is now listing the Kojak in 355. That will also take 1.2 pounds off of your bike.
    Well the back tyre has given me hassles. I already got 2 punctures (glass) which seems pathetic considering it has a Kevlar belt. Just further proof to me that Kevlar is a waste of money.

    Plus the rear tyre threatened to blow off the rim 3 times during commuting last week. I was JRA and had just gone over a very minor bump when I felt the rear brake rubbing in a spot. Checking showed the tyre bead perched on top of the rim. I was able to save a blowout all 3 times. The LBS agreed on a new tyre, so I got a Marathon Racer instead after paying in the difference, and installed a Slime liner for proper puncture protection.

    We're going on a tour next weekend:

    day 1
    day 2
    day 3
    day 4 - retracing day 3

    Got me some Deuter panniers (with Ortlieb catches) for the trip and commuted with them for a shakedown. Perfectly happy.
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  21. #46
    crazy bike girl msincredible's Avatar
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    Partial repost from NorCal:

    I rode my Birdy up Page Mill today!
    http://www.bikely.com/maps/bike-path...y-scenic-hilly

    Oh, and yes, I was creaking, whistling and rattling the whole way.

    Descending through the twisties, I had a new sound...then I realized I was scraping the little chain guard on sharp right-handers.

    And on a straight descent (probably going 25-30) I tried again no-handed, no issues (I did keep my hands close to the bars just in case).

    Plus, had a couple of entertaining encounters on the way home...

    First was on Alameda de las Pulgas. Some guy on a road bike passed me, working hard. Once he felt he had gotten far enough ahead, he sat up and relaxed. Well, we got to a bit of a hill, and I was able to make up the difference. He didn't notice until I was right on his ass, then he looked back, saw me, and stood up to mash up the rest of the little hill. Unfortunately for me it leveled out, I can't keep up on flat ground.
    Guess he didn't like the idea of being passed by a girl on a clown bike.

    Then by El Camino, met a woman on a comfort bike and had an interesting conversation as we waited for the light:
    Her: That's a really cool-looking bike!
    Me: Thanks!
    Her (dead serious): Is that a road-racing bike?
    Me: Um, no, it's a folding bike.
    Her: A what?
    Me: Folding. It folds up, small (made some hand motions to illustrate).
    Her: You have got to be kidding me!!! So you can take it on the bus???

    I was having a hard time holding back the laughter...I mean, I can't think of too many bikes that look farther from a road-racing bike.
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  22. #47
    Car free since 1995 pm124's Avatar
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    it will be interesting to see whether you notice a difference. I found the Racer to be sluggish. Did you replace both tires? The front matters almost as much as the rear.

    I have a 349 wheelset and used a Brompton Green with great success. I've had a higher average speed with that tire than with a Stelvio+Slime liner and only 2 flats in 1500 miles.

    Let us know how the tour goes.

  23. #48
    Senior Member
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    I did a Palomares Road loop for the first time today on my Birdy. I actually started in Pleasanton, heading south on Foothill Rd (the route is plotted going the opposite direction).

    http://www.bikely.com/maps/bike-path/217409

    Not too much bike noise for me since I tightened everything this past weekend. My climbing skills leave much to be desired as I had to stop a couple of times going up Palomares Road to catch my breath. It still feels a little unnatural for me when I am out of the saddle compared to riding a full sized bike, so I typically spend most of the time in the saddle on climbs. I'm thinking it's somewhat due to the more upright riding position, or maybe I just need to practice the technique more.

  24. #49
    crazy bike girl msincredible's Avatar
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    Quote Originally Posted by jeffy1021 View Post
    It still feels a little unnatural for me when I am out of the saddle compared to riding a full sized bike, so I typically spend most of the time in the saddle on climbs. I'm thinking it's somewhat due to the more upright riding position, or maybe I just need to practice the technique more.
    I have found that on steeper hills (15-20%) the Birdy really wants to wheelie, particularly when I have a heavy backpack on. To compensate, I really have to get my weight over the front wheel, which feels unnatural ergonomically for climbing. Maybe what you are feeling is related?
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  25. #50
    Senior Member
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    Quote Originally Posted by pm124 View Post
    it will be interesting to see whether you notice a difference. I found the Racer to be sluggish. Did you replace both tires? The front matters almost as much as the rear.
    My Racers feel a lot quicker at maximum pressure (85psi). They feel a lot slower at 75psi (guage with unknown accuracy) but still a lot better than the original Birdy tires.

    David

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