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All-in-1: Questions about SS 'cross and fixed-gear bike....(11 posts)

All-in-1: Questions about SS 'cross and fixed-gear bike....SS_MB-7
Jan 26, 2002 8:06 AM
I was just about to buy a fixed-gear bike (Soma Rush), but then thought, why not get a singlespeed specific 'cross frame (Spot, On-One, Curtlo, etc) with a flip-flop fixed/free rear wheel?

I'm thinking of either Mavic Open Pro or CXP33 rims? I'd like something light for fixed-gear road riding, but strong enough for 'cross racing/riding. BTW, I'm only 130lbs.

As for the hub, I'm not sure what my options are in terms of a 135mm rear fixed/free flip-flop other than a Phil Wood -- beautiful, but expensive! Any other options?

As for gear ratio, I'd go with:
- 36:18 free for 'cross racing/riding and
- 44:16 fixed for fixed-gear road riding. Does this sound reasonable?

Now, what cranks should I go with? Would a MTB crank be better suited? With a MTB crank, I could easily go from a 36 front ring (inside of spider) to a 44 (outside of spider) since they share the same BCD. What about road crank/rings?

Brakes calipers and levers? I was thinking of using 105 levers with Avid Shorty brake calipers. Is this a good set-up? What about V-brake calipers? Can these be used with 105 levers?

Anything else I should consider?

Ride Hard,
Mike B.
some thought:buffalosorrow
Jan 26, 2002 6:33 PM
On my Graham Weigh cyclocross frame with horizontal dropouts, I have Mavic CXP 30's (32 hole) laced to Suzue Pro Max flip flop hubs, I would have perfered the new Wood hubs but the cost held me back. My wife has the phil woods on her Aegis singlespeed, I must say they are the best.

Onward.... on the Graham Weigh are Raceface SS Aluminum cranks 175mm. Plenty stiff.

As for gear ratio on the GW, I am runnning:
Fix: 32:13 (Road/ easy off raod)
Free: 32:16 (Off road/ trails)

On my old Motobecane "never say die" courier tank:
Fix: 42:13
Free: 42:16

Some thought on the lever/ brake combo. The modulation with most road levers and cantilevers is weak. The Dia-Compe 287 lever has a "longer pull", I am waiting for these to arrive in the mail.
Have you considered top mount levers? I have never tried them but have a pair waiting for the GW, many riders in Europe ride with them.
There was some topic talk regarding Tektro Mini V brakes, regular V's and road levers are plain out too squishy, I have this set up on the front of my Colnago (a must replace).
Otherwise the 105 levers and Avid shortys will do fine.

Other thoughts: When you are running inner and outer chainrings, just be sure you chain line is straight.

All the best.
Avid ShortysHENRY K
Jan 27, 2002 5:41 PM
I have Avid Shorty 6s on my cross, and I am not happy with them at all. Maybe it is because I just went from a road bike with road brakes to the cross. The braking just does not seem as crisp and positive as my road brakes were. Any suggestions? I ride more on road then off, but the cross just seems so much more versatle.
Avid Shortyscptnpwdr
Jan 29, 2002 6:32 PM
who set them up?
adjusting cantis takes time and patiencebuffalosorrow
Jan 29, 2002 6:37 PM
There is a mathamatical equation for perfect set up, I found a number of weeks ago. It has to do with stirup, cable lengths and angles.

Try: http://www.sheldonbrown.com/harris/

Btw the avids do not get great praise, but better cantis are costly. Try working on the avids.

Good luck
re: All-in-1: Questions about SS 'cross and fixed-gear bike....climbo
Jan 28, 2002 5:53 AM
I second that question, are you running 2 rings up front? This will wreak havoc on chainline problems. You'd be better off to just swap out your ring and chain when you switch from fixed to free. I keep a spare track chain ready to go at the correct length to swap it out easily.

Cranks, MTB is probably a good idea. The smallest I can get on my Shimano road cranks is a 38 ring. I used to run a 38:17 or 38:18 free and a 42:15 fixed so yu're gearing sounds very reasonable to me.

Rims - Open Pros and 33's are both strong enough for CX. I am 155lbs and run Open Pros and CXP 23's which hold up to plenty of abuse.

Hubs - isn't the Surly a flip-flop? What about a Spot, do they make them? check out their website. If not, you can get any flip-flop 120mm track hub and space out the axle for the extra 15mm. This affects your chainline (you'd probably need the ring on the inside of your cranks) and might not hold up as well as a Phil Wood on the dirt.

Brakes? I use canti's but I hear the Avid's are quite good and cheap.

Good luck with it, post a pic here when it's done.
Some more questions for you....SS_MB-7
Jan 28, 2002 9:05 AM
I'm still not sure as far the crank/chainring/rear cog set-up. I can either go with a fixed front ring that could be used with either rear cog/freewheel (ie, 36T) or, I could change the front ring depending on whether I'm riding fixed or 'cross.

After several extended road rides this weekend in which I forced myself to stay in 1 gear, I found that 39:14 provided the best all-around gear combination. This is equivalent to 73.2 gear-inch.

If I was to go with a 36 front ring for both applications, I would use a 18T for 'cross (2:1) and a 13T fixed cog (which yields 72.8 gear-inch). This would be ideal since I would not need to swap the front rings and the chainline would always be set. Just flip the rear wheel, install new tires, and chain and ride!

Or, I could go with a 36:18 free-combination for 'cross (2:1) and a 50:18 fixed-combo (73.0 gear-inch) for fixed-gear riding. This would mean removing/reinstalling a different chainring depending on the application. So, in order to maintain the same chainline, the 50T chainring would need to installed on the inside of the spider since a 36T cannot be installed on the outside of the spider due to the crankarm. Are there any issues with a 50T on the inside of the spider?

By using the same rear cog/freewheel, this would make it easy to swap between fixed/free while riding, i.e., if your legs became tired half-way through a ride, etc.

What do you think? This is new to me so I'm trying to think of all the possibities.

Surly does offer a flip-flop, but I'm not sure if it is fixed-free or free-free. From the product description and picture on Surly's site, it appears to be free-free. I don't belive Spot has flip-flop hubs.

Ride Hard,
Mike B.
Some more questions for you....climbo
Jan 28, 2002 11:04 AM
Mike B.

I would do A) keep the 36 ring (or 37, 38, 39, 40 would work) up front and use what you need on each side of the flip flop. Any of those rings is going to let you use a 12-18 fixed cog and a 17-20 freewheel for your perfect combimation, it just depends on how hard you want to pedal.

This would be the cleanest and easiset solution in terms of re-arrnging your set-up each time. Having it the other way with two 18's on the rear is nothing special, if you can push the 18 fixed it's just as hard to push it as a free.
Surly 1x1 hubbuffalosorrow
Jan 29, 2002 6:45 PM
True that the Surly hub is double treaded, threaded on both sides for freewheels. Same goes with the spot. To run a track cog you have to thread a lock ring after the cog (Same direction thread, helps to use some lock-tight). On track hubs there is threading for the cog and a reverse thread for the lock ring this is much safer.
re: All-in-1: Questions about SS 'cross and fixed-gear bike....flyweight
Jan 30, 2002 3:13 PM
I pretty much own the bike you're looking for. I've got a Gunnar (Waterford) single speed 'cross frame and it's hands down the most enjoyable bike I own. Gunnar quit making these frames as cross bikes (now they have sidepulls) but you can still find them. The bike is an absolute blast to ride and the handling is perfect.

Mine is set up with a Suzue disco rear flip-flop hub with a fixed/free set-up. (the Gunnar uses 120mm track spacing) Cranks are some old Campy BMX cranks from the 1970s. Can't remember the gear ratio, something like 44x17. I've got Kenda cross tires which are light, grip well in the dirt but are smooth enough down the center for fixed gear road riding. Bars are Salsa Short n Shallow in a wide 46cm for extra leverage on San Francisco hills. Brakes are Paul cantis. I tried Avid's and found they tend to squeel too much. All the Bianchi cross bikes we sold that came with Avid's had the same problem. Go with older Shimano canti's (cheap) or one of the boutique brakes (Empella, Paul, etc)

The Soma Rush is a nice bike. We sold one a couple of months ago to Robin Williams. (http://www.americancyclery.com/SOMA/frontpage.html)
Hey Flyweight -- Rush questions....SS_MB-7
Feb 1, 2002 7:18 PM
I'm interested in buying a 53cm Soma Rush with your "Best" kit, but I am concerned about the standover height. What is the center-center seat tube length and standover height (with 700x23 tires) of the 53cm Rush?

Ride Hard,
Mike B.