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Gearing, Bar ?'s(17 posts)

Gearing, Bar ?'sTrevorInSoCal
May 13, 2003 12:33 PM
Recently built up a semi-beater (beater frame, but with some decent parts) fixie for commuting/townie use. (see this thread over on the mtbr singlespeed board.)

This is my first fixed-gear, and so far I'm enjoying it, but I've got a few questions:

1. What's with the bullhorns, moustache, and other bar variants? Are they actually more versatile than drops or is it mostly a style thing? I decided to stick with what I know, and I found a pair of Ritchey biomax pros on sale for $20, so that's what went on there (Just installed those and the new, cheap, tektro levers last night, so they aren't in the pictures.). Any compelling reason I should consider alternates if drops are working for me?

2. Gearing. I'm running 42x13 now, 'cause that's what size cog the friend who built the wheel suggested/ordered. On my mostly flat, with a couple rolling hills, commute this gearing feels a little high. I'd rather spin than grind (I do plenty of grinding while climbing on my SS mtb.), and I'd imagine any ride with *real* hills is really gonna be a struggle. However the sum total riding I've done on it so far is my 10 mi. commute 3 times. (r/t yesterday, plus the ride in this morning.) Dunno if 3 rides on the same route is sufficient to judge my gearing needs. Will I eventually get stronger and adjust, or should I gear down to something like a 42x15-16 to be more comfortable/save my knees? At the very least taking off from stoplights would be easier with a couple more teeth in the rear...

3. Computers. Is there a computer for fixed-gear use that will compute cadence based on programmed gearing and speed? Kinda like the Shimano flight deck but with only one gear?

Thanks.

-Trevor
That's sky-high, actually ...Humma Hah
May 13, 2003 1:36 PM
... yeah, 42:13 is 3.23:1. With a typical wheel, that'll give 84 gear inches. Track bike stuff.

A better starting point would have been about a 16 or 17T rear ... 42:17 would give 2.47:1, typically chosen as a good general purpose gear. 42:16 would give 2.62:1.

I'm comfortable in the 2.5:1 to 2.8:1 range, and I've been singlespeeding for about 44 years.
That's sky-high, actually ...TrevorInSoCal
May 13, 2003 2:24 PM
In that case that brings up another question...

I've read/heard that you should stick to one type of cog because of slight variations in the threads. Otherwise you might mess up your hub threads. There's a surly cog on there now which uses an ISO thread. Should I stick to Surly if I replace the cog or can I switch brands w/o mangling the hub threads, as long as I use a cog w/ an ISO thread. In which case, what other cogs use an ISO thread?

Surly doesn't have as wide a selection in their 3/32 cogs (running a 3/32 chain) as some other brands. According to the Surly website they have a 13t and a 16-20t in 3/32. That's fine if 16t works for me. But if I want something between 13 & 16 it doesn't look like I can get it in a Surly cog...

As for the Phil Wood hub. I had a set of Phil wood hubs off an old road bike (my first road bike, bought used from a shop employee who had cobbled it together from spare parts) that had a thread-on 6spd freewheel. Brent at Phil Wood told me I might have chainline/spacing issues if I tried to use it for a fixed or singlespeed, but offered me a $60 trade-in credit for the old hub towards the purchase of a new one. Couldn't pass that up. The front wheel is currently being built with the old Phil front hub.

Oh, and thanks for the help.

-Trevor
Nothing lasts forever ...Humma Hah
May 14, 2003 6:22 AM
As long as the cog threads on smoothly, and is seated firmly so it doesn't wobble or work the threads, any minor mismatch is unlikely to be a serious problem. In any case, no hub with aluminum threads will last forever.

As long as the hub is not too wide for the frame, spacers will fix almost any chainline problem. Since you're building the wheel, it is also no problem to dish it to place the rim just where you want it after applying whatever spacers are necessary.
re: Phil hub/Surly cogukiahb
May 20, 2003 9:14 PM
There is something to what you heard about thread compatability, I also have a really old Phil freewheel hub and tried a Surly cog on it, but it was difficult to screw on, though the hub threads are in good condition. I then tried a Shimano BMX freewheel which spun on easily, so I welded it (the freewheel) together for fixed gear use and it works fine so far...and the chainline is better too.
I like that head-badge, BTW ...Humma Hah
May 13, 2003 1:47 PM
Not too shabby for a "beater". Kind of a "wolf in sheep's clothing" ... that Phil hub is a good one.

With singles and fixies, what I've done to determine cadence is just crank out a speed to cadence conversion table that I can tape to the handlebars on those rare occasions where I care to know. Something about the size of a playing card should be plenty. That approach would be a mess on a geared bike, but works fine on a single.

Knowing your cadence/speed relationship can be worthwhile as you're getting used to your gearing or for performance training, but you'll probably learn what you need to very quickly, and thereafter not need to know cadence, just speed.
Best advice I can give about bars.....Trevo
May 13, 2003 8:37 PM
It depends on how fast you want to go. ON my Trek bike at first I can a riser bontrager stem with upside down steel cruiser bars(moustash). This was a good set-up for comfort, but I still wasent reaching,what I though, to be a fast speed easily. Flat bars arent bad also, fo around town and comfort wise. I hacked some trash can bars up and made some bullhorns, they are nice and aero. I see them alot on messanger bikes and would assume they are provide the most aero position.
My VERY last choice of bars was shallow road bars with a 120mm 17degree drop stem. At first I was reluctant, but I've found them to be the best compromise. I have bar tape on just the end. Iam sticking with these bars for now or untill I get some track bars.
Basically, try a set-up untill you find something you like. If your commuting long distances them I suggest moustash bars.
I run a 42x15 drivetrain and cant complain.

I know nashbar makes a cadence computer for only 25 bucks.

Are those velocity rims? what model?
Id that a 911 Porche in the background?

Trevo
Thanks.TrevorInSoCal
May 14, 2003 10:57 AM
The rims are Mavic Open Pros. Was gonna go cheaper, but the friend building them convinced me that since I already had the nice, new Phil Wood hub I might as well not skimp on the rest of the wheel. The wheels, once the front gets built, will be the most valuable parts on what is mostly a bargain-bin creation.

Not sure about the model or vintage of the Porsche. That's the neighbor's car. He's sort of a gearhead. It's got too many wheels for me to be all that interested in it...

The bars feel all right for now, but I need a longer stem (Which is gonna be hard to find 'cause it's an odd size. a 22.2 doesn't fit. It's a 21.6 or something like that.). Ordered a 16t cog as well. I need a bit more oomph pulling away from lights and the 13 just isn't doing it for me. The fastest I go anywhere on my commute, is just under 30mph, don't think I'll have too much trouble spinning a 42x16 at that speed for short distances.

-Trevor
BarsSteve_0
May 14, 2003 3:52 AM
drops are by far the most versatile.
moustaches come next
bullhorns a distant third (only 2 hand positions).

I think you see a lot of bullhorns on FGs because, for most people, a FG is a secondary bike. Bullhorns add a twist of flavor.

That gearing is way too high.

The beauty of FGs is that you dont NEED a computer; the ratio never changes! speed = distance/time, where distance is a fixed product of pedal rotation (on a FG). Takes a little brainwork, but you dont have a dorky computer junkin up your new drops.
Cadence formulapauly
May 14, 2003 4:39 AM
Here is the cadence formula I use for my fixie:

Cadence = (2682.17 * mph) / (ratio * rollout)

Where "ratio" = chainring teeth / cog teeth and "rollout" is the exact circumference of your tire.
re: Gearing, Bar ?sdzrider
May 14, 2003 5:31 AM
Can't speak to the bars. I see all kinds. I'm used to drop bars and use them. I have thought of trying moustache bars with the ends rotated half way down from horizontal so my arms are close to straight with my palms facing inward.

The gearing sounds real high to me, but I'm old and fat and struggle a bit climbing some of our CT hills with a 42x15.

A computer on a fixie sounds like more of a contradiction than I could easily handle at my advanced age.
re: Gearing, Bar ?sTrevorInSoCal
May 14, 2003 11:06 AM
A computer on a fixie sounds like more of a contradiction than I could easily handle at my advanced age.

I just like having stats available. Not quite sure why. My geared FS mtb, and my geared road bike both have computers.

OTOH, my singlespeed mtb doesn't have a computer. I just get on it and ride. I guess a fixie would follow a similar ethic. Plus that's one less thing to get ripped off when it's parked at the grocery store/coffee shop...

-Trevor
Beware the Dark Side of singlespeeding ...Humma Hah
May 14, 2003 11:44 AM
Yeeessss, I can feel your enthusiasm growing. That's it, put the 16T cog on your fixie ... ride it ... feel the smooth power flowing from your legs into that smooth pavement! Soon you will be OURS! Soon, like me, you will become an un-geared roadie, and rarely visit that frantically-active MTBR Singlespeed forum again!

And since you're in SoCal, notice how close you are to the San Diego Velodrome. Check their website. Notice the seductive "open-to-the-public" riding schedule. Try it. Sign up for their beginning track class, then intermediate, then start racing.

Ride it on the AmTrack Century, the Tour de Palm Springs, Solvang ...

Bwaaa-ha-ha-ha!
Not likely ;)TrevorInSoCal
May 14, 2003 9:50 PM
Soon you will be OURS! Soon, like me, you will become an un-geared roadie, and rarely visit that frantically-active MTBR Singlespeed forum again!

Well, since I'm leaving in about a month to spend 2 1/2 months off road on a geared mountain bike (The horror!) I don't see that happening too soon...

Maybe the Great Divide will cure me of my mountain bike addiction, but I kinda doubt it ;).

-Trevor
where to?SmogRider
May 14, 2003 10:20 PM
where ya headed? racing?

BTW - I ride 42:17 and it works well. May do the 70 miler L.A. fun ride this weekend on it.

It's me, Hollywood
Check the last line of the mesg...TrevorInSoCal
May 15, 2003 8:39 AM
I'm riding the Great Divide Mountain Bike Route this summer. Signed on with the Adventure Cycling Association tour starting in June.

Didn't know there was an LA fun ride this weekend. You're not doing the nationals at Big Bear? I'll be up there but I'm not racing. Gonna load some weight into the BOB and ride up Clark's Grade Saturday morning and then bum a ride home from a friend who's racing...

-Trevor
right...SmogRider
May 15, 2003 9:57 AM
guess I didn't put 2 & 3 together...

that's awesome that you're riding that! Damn! I've *fantasized* about riding the cont. divide from Montana to Mexico, is that the same ride?

I have friends going to Big Bear...I'd rather ride than hang out, even tho the atmosphere will be coolio.

going for 70 mi. on the Trek fixie.
HW