Rainy Day Cyclo-Bomber

Deej

Maximum Pace
Oct 13, 2007
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83
Setagaya
#1
I've been transforming my papa-chari -- a 1993 steel KHS mountain bike -- into a single-speed cyclocross commuter beast. And I gotta say, I am loving it.

Today, I took it out in the rain and bombed around the city roads, then on the gravel, mud and grass along the Tamagawa. After all my skinny-tire-and-carbon cruising, it felt kind of ... liberating ... to get in the drops and charge full-bore over curbs and potholes and mud on a steel beast -- all while not giving a thought to shifting, as there was only one gear. I had images of Roubaix, strade bianche and the Rocky Mountains dancing through my mind as I chattered over the rough terrain.

Off with the baby seat. Off with the big-@ss knobbly tires. Off with the flat bar. Off with the front derailleur.

On with the super-robust, lightly treaded 1.5-inch Schwalbes. On with the drop bar. On with the Tektro brake levers.

It's still got a kickstand, which comes in handy but will probably go, because, well, it's a kickstand. The next step is to remove the rear derailleur and just have one cog up front and one in back. I also need a chain tensioner. Oh, and I have to lose the rusty old pedals and slap on some Shimano SPDs or something similar.

A couple questions: do any of you have gear-ratio recommendations? As I said, it's a single-speed (but not fixed), so I need a combo that allows me to cruise at a good speed but not blow out my knees.

Also, do any of you have experience using a tensioner? Is there anything I should be aware of before buying one?

I'm actually not dreading the coming of rainy season now. I'll just hop on the bomber and tear it up!

Deej

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GSAstuto

Maximum Pace
Oct 11, 2009
945
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103
tokyo
www.roadfixie.com
#2
Love it! One suggestion - dis the coaster and make it a full fixed! You wont regret it. Besides just getting you to work, you'll be able to naturally pickup a 360 pedaling pattern. Plus - you can drop the brakes - skidding is just as effective in the city. Oh - and I think bullhorns instead of drops. Easier to hang the plastic conbini bags with the 40's and milk you need to pickup.

BTW - In terms of tensioner:

1) http://www.bike-mailorder.de/shop/i...t=551&filter_id=42&tfilter_id=B&cPath=548_551 Minimum reduction of street cred ration (SCR)

There are quite a few trailing arm tensioners out there.

2) Eccentric hub. http://www.sheldonbrown.com/harris/white-hubs.html Super sweet - but reduces your street cred ratio.

3) Half link it. Chances are after several chu-hi's and various cog combinations you will come to the magic ratio which will allow you perfect tension , but require a half link. No worries - just hack together a half link from the cheapest chain you can find. Street Cred Ratio on this is max. If you get it together under 6 Chu Hi - then SCR rating is about 92.

4) MAPP GAS IT! Damn the torpedo! Just wack off the vertical drops and braze on some horizontal ones. Preferably from a retired keirin frame you found in the garbage behind the Omiya track. SCR on this is at least 150

Tires:

The Conti Gator Skin is the tire of choice. After you skid out the rear - just transfer it to the front for 1000's more km of riding pleasure. http://www.conti-online.com/generat...etyres/ultra_gatorskin/ultragatorskin_en.html

Wear:

1) Get one of the cycling jackets from 100yen store and then slice off the front to make a perfectly tailored 'team wrap'. It folds small enough to stuff anywhere and if you lose it - no worries.

Ratio:

1) The DEEJ - must be near knee blowout - so , my guess is you'd feel fine at a 49/16 for anywhere except sustained 10%

2) The GOLD - from ancient Emiglio-Romano winter valley muletto training. This is firmly established as a 42/18 and you can attack any hill as well.

3) The PDX - messenger favorite balance between the DEEJ and the GOLD. 44/16. Use a Sugino Messenger (130) for the front chain wheel for max effect.
 
Apr 18, 2010
29
0
0
Daikanyama, Tokyo
#3
Great to see you have seen the light! Take it fixed so that you can experience the ultimate cyclogasm.

42x18 (2.33) is a good ratio if you're doing hill climbing and fireroads. If you're just hammering on the flats, you could run something around a 42x15 (2.8). Traditional Japanese track gearing is 49x15 (3.2), but its killer.
 

Deej

Maximum Pace
Oct 13, 2007
1,018
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83
Setagaya
#4
Thanks for the feedback, fellas. I truly appreciate it. I kind of guessed that the fixed-gear enthusiasts might have something to say on this subject. :) I'll be thinking about your suggestions and let you know how it all turns out.

I just told GSAstuto in a PM that I think I saw you two cruising through Kinuta Park yesterday, where my son had a soccer game. If you saw a foreigner in a red Campy cycling cap, that was me -- though I don't think you guys spotted me. I would've said hi, but you were a little too far away. Next time!

Yeah, fixed. I'm a little scared to let go of the ability to coast. It just seems so...practical and safe. But I dig the simplicity of fixed and would probably benefit in terms of pedaling form.

Also, my rig seems almost too big and heavy for fixed. But maybe that wouldn't be an issue at all.

I'll keep you updated on the transformation. Hope to see you guys on the road soon!

Thanks again,

Deej
 

Mike

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Sep 24, 2007
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58
Kanagawa
#6
Deej cool wheels, but beware of those fixie dudes. Once they have you in their mitts they'll pour wax in your ears and have you shouting 'fixie, fixie' from the hill tops:p
 

kiwisimon

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Dec 14, 2006
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Japan
#7
Go with the big chainring on the bike at the mo', flip it into the middle position on the cranks. I wouldn't worry about going fixed as it won't improve your spin any more than a regular bike. Sure the fixie heads will tell you that, but they are wrong, (too many cyclogasms behind their logic). I would just throw spacers(the plastic ones between the cogs) on your rear cassette and experiment till you get the gearing you like the best. You have 7 or 8 to choose from. For a start you can just use the derailler on the bike and use the limit screws to lock it in place. After you get the ratio you like the half link will be your friend. here is a picture from Sheldon
http://sheldonbrown.com/singlespeed.html
 

AlanW

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Jan 30, 2007
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Tokyo
#8
Deej, the world of mountainbikes weeps for a lost brother! :(

But I understand you must do what you must do, and if the new setup leads to a new lease of life for the old stager (the bike I mean :heyhey:) then it's all for the good.

To keep the road spray from the front wheel managable on wet days, these Crudcatchers are quite effective.

As for fixed, well it's not going to work too well with a chain tensioner, which are only designed to maintain tension on the unloaded side of the chain. Without a freewheel, either side of the chain can be loaded and I expect the tensioner will be ripped straight off. But you could probably do it with careful selection of front & rear cogs and maybe a half link as well.
"Skidding is just as effective in the city"
No it isn't. Max retardation by a locked rear wheel in the dry is about 0.3g due to forward weight shift under braking. Max retardation by a front wheel at the point of lockup or flipping the bicycle is almost 0.7g, again in the dry. More than twice as effective.
Removing the front brake for a bike intended for city use in wet conditions is extremely foolish.
Enjoy the new/old beastie!
 

GSAstuto

Maximum Pace
Oct 11, 2009
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tokyo
www.roadfixie.com
#10
Here's some article about FG on some guy named Lance's site - it's pretty right on.

http://www.livestrong.com/article/111894-benefits-using-fixed-gear-bike/

Agreed the raw physics of skid traction front/rear bias favor a front brake - so , just keep the front brake! Then you get the best of both worlds - hard stops or checks by front brake and can still leverage the benefits without cheating too much.

The solid mounted chain tensioners ARE intended for FG. Personally I don't like them - and prefer to setup either a half-link 'just tight' chain, or a frame with horizontal drops. For a real muletto frame half the fun is seeing how cheap you can build it. My old Panasonic lasted more than 20yr as a muletto with a crossthreaded cog, aircraft grade locktite and a cobbled together half link chain. Only this year it finally failed (in true explosive fashion) as I stood hard to avoid a cement truck and managed to break a chainstay AND spin the cog!

Anyway - once you have the wheel / chainline sorted you can easily swap between fixed cog and freelie. I've got a spare 16t freely floating around here, too, so if you want to try , please give a shout. Or - if you're in the hood - lets just hook up and you can try out the flip /flop with James. If you ask nice he might let you ride the Colnago - but then you'd be hooked forever.
 

AlanW

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Jan 30, 2007
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Tokyo
#11
The solid mounted chain tensioners ARE intended for FG. Personally I don't like them - and prefer to setup either a half-link 'just tight' chain, or a frame with horizontal drops.
Cool.... I have never seen a solid mounted one, only a lever-arm type. Nice to have options :)
 

FarEast

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May 25, 2009
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Yokohama
#12
sorry to hijack the thread but can a fixie be turned into a geared bike?

Totally sacrilegious to you guys but just wondering as I have my mind set on a little project using some old school campy parts and a reproduction of Pinerallo's first ever bike.
 

GSAstuto

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Oct 11, 2009
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tokyo
www.roadfixie.com
#13
Chain Tensioners

I tried a couple of these but they suffer from too much drag, noise and just plain 'wonkiness'. Essentially they are an idler wheel that you can adjust against the backside of the chain. Using the half-link cobble is generally good enough for an around the towner and you play around with the cog wheel combos to get as snug a chain as possible.

I love the idea of the eccentric hubs - but at $150+ , they cost more than my whole clunker altogether! Though it would allow conversion to a clean single on just about any frame laying around - which would be quite nice for winter training. So, I'm very tempted...

Cool.... I have never seen a solid mounted one, only a lever-arm type. Nice to have options :)
 

GSAstuto

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Oct 11, 2009
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tokyo
www.roadfixie.com
#14

GSAstuto

Maximum Pace
Oct 11, 2009
945
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103
tokyo
www.roadfixie.com
#19
Nice!

Wow! I'd hate to mashup the dropouts on that - but since it is aluminum you probably could TIG a hanger. Would be a travesty, though. Yeah - the Nexus may be a stealth way to get the job done. Also - wish they would have used the FSA 'Gimondi' Crankset - that would really fit well with the retro build. My guess is the Most SS Crank is likely a 3/32, so you should be fine there. For some reason the FSA SS (as opposed to TRACK) cranksets use 3/32 chainrings.. go figure.

Before you hack it up, though, can I take it for a test ride? :)

Hmmm..... this is the bike

http://www.pinarelloftp.com/images/lungavita_423_big.jpg

So I guess i'm out of luck. :eek:uch: