Go Back  Bike Forums > Bike Forums > Singlespeed & Fixed Gear
Reload this Page >

Affects of too big cog on Fixie

Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

Affects of too big cog on Fixie

Reply

Old 12-05-18, 09:01 PM
  #26  
Gresp15C
Senior Member
 
Gresp15C's Avatar
 
Join Date: Sep 2014
Posts: 2,358
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 517 Post(s)
Originally Posted by j_e_r_e_m_y View Post
You don't know the half of it. Dude's garage foundation was just WRECKED. It's a miracle it's still standing.
The moral is that the bike should have had a kickstand, for the safety of the entire subdivision.
Gresp15C is offline  
Reply With Quote
Old 12-05-18, 09:21 PM
  #27  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 6,087

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 1302 Post(s)
Originally Posted by Altimis View Post
Your feets will not unclip by itself if you tension correctly and its not worn out clips.

If going downhill make your legs outspin and unclip by itself, you lose control and don't have brake on it.

Use your feets to rub rear tire (not the wheel itself or you risks break wheel spoke) and act it like conventional rim brake.

Your shoes probably blow out though if you don't mind trashes it after ride.

AKA seriously, if you can't take full control of it, put brake on.
I have ridden 42 X 17s and the like for decades. Have gone down many hills far faster than 25 mph. (Back in my crazy days, down Jauquim (sp) Miller in Oakland, CA. That was a regular ride. Never got passed.) I will flat out not ride ride a fix gear with clipless pedals because my experience is that when pedaling over 200 RPM (40 mph) I have no idea whether I am keeping my foot straight - and I know I tend to angle my foot into turns; absolutely not where I want to ever unclip. Instead I ride toeclips and straps and cleated shoes, straps pulled tight.

Ben
79pmooney is offline  
Reply With Quote
Old 12-05-18, 09:34 PM
  #28  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 6,087

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 1302 Post(s)
Originally Posted by j_e_r_e_m_y View Post
To get back to the original question, "Affects of too big cog on fixie", lemme drop some knowledge on ya, son.

A lot of these replies are trying to confuse the issue with talk about "gear ratios" and all that technical ish. Don't fall for it.

Real talk, you bring up a good point and a got damn valid concern. And here's the scoop - too big of a cog is a HUGE issue when tearing ish up on your sw8 fixie. Follow me here - when things get bigger, what do they do? That's right, they WEIGH MORE. You get all crazy and put something bigger than a 19t cog on that rear hub and you are playing with fire my friend, throwing the weight balance into disequilibriumisation like that. Do you want your bike to fall over on it's drive side from all that excess heft? Hell no you don't.

True story - buddy of mine bought a 22t cog for his sw8 a** Bigshot fixie (green grips, orange deep deep deep V's, thing of beauty), and was all stoked to shred but then reality swooped in like the fickle b**** she is. Dude was so proud when he threaded that glorious stamped steel onto the hub, I'll never forget that. Used his best pipe wrench and everything to torque the lock ring down. Soon as he was done tho, the bike fell over hard to the right, and to this very day, the damn thing is still lying there in his garage, drive side down, and no one can even stand that sweet beautiful ride up anymore. We tried, bribed a whole bunch of friends (who can say no to ice cold Natty Light, amirite?) to help us try to pick it up but at the end of the day... that cog was just too big. I know I gave it my best, but damn if I don't still got the hernia scar that will haunt me to my grave.

Moral of the story? Small cogs are your friend amigo. Ain't nobody got time for the pain and hassle of a too big cog.

Peace
That's what your buddy gets for hanging out with feeble upper-bodied roadies. I own and have ridden a 24 tooth cog on my fix gear with no issues. I do lay my bikes down on their left sides so I have never seen what you buddy saw. And yes, I get to lift it a shorter distance when I pick my bike up. But a much bigger factor is that I ride fix gears enough (and in hills) that I have a modicum of upper body strength (a lot of the time in regular flat ground gears like 16 and 17 tooth cogs).

Ben
79pmooney is offline  
Reply With Quote
Old 12-05-18, 09:57 PM
  #29  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 20,127
Mentioned: 124 Post(s)
Tagged: 0 Thread(s)
Quoted: 7082 Post(s)
Originally Posted by mtb_addict View Post
I'm riding 42x18 on a coaster hub

My question is about Fixed Gear. If the bike is travelling 25 mph downhill...how fast does my leg have to spin to keep up?
Try on your bike to keep up with the pedaling downhill, without going slack or spinning out. I assume the fixie is a bit easier as it will drive the legs if you don't, up to a point.

Here is a calc page.
BikeCalc.com - Speed at all Cadences for any Gear and Wheel
BikeCalc.com - Cadence at all Speeds for any Gear and Wheel

700c x 28
42/18

So, at 25MPH, you should hit 137 RPM. It is probably ok.

I have a hill that has pushed me up to 54 MPH. That would only be 296 RPM... not too bad.

My goal is to hit 55, which would be 302 RPM on your bike.



I know, a steeper hill would be nice. I have one in mind. But, it also has to be a good straight shot descent.

One question, do you have brakes on the bike, or are you trying to go brakeless. What about some kind of foot retention? Toe Clips? Clipless?

I haven't done the fixie thing, but I'd imagine that it would be much hard to control stopping if you get pedaling up to 150+ RPM, at least to do so safely.
CliffordK is offline  
Reply With Quote
Old 12-06-18, 02:06 PM
  #30  
BoozyMcliverRot
Senior Member
 
BoozyMcliverRot's Avatar
 
Join Date: Jan 2007
Location: bradenton FL
Posts: 975

Bikes: 1991 Diamondback Master TG 1990 Trek 850 Antelope

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Whatever you do,just make sure your log and cockring are tight.
BoozyMcliverRot is offline  
Reply With Quote
Old 12-06-18, 02:43 PM
  #31  
mtb_addict
Senior Member
Thread Starter
 
mtb_addict's Avatar
 
Join Date: Jun 2011
Posts: 3,167
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 2305 Post(s)
Originally Posted by BoozyMcliverRot View Post
Whatever you do,just make sure your log and cockring are tight.
How many ft-lb tight?
mtb_addict is offline  
Reply With Quote
Old 12-06-18, 02:52 PM
  #32  
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Posts: 31,443

Bikes: everywhere

Mentioned: 47 Post(s)
Tagged: 1 Thread(s)
Quoted: 3254 Post(s)
Originally Posted by mtb_addict View Post
How many ft-lb tight?
Never seen a lockring hook spanner attachment for a torque wrench,

I just go for gutenteit
LesterOfPuppets is offline  
Reply With Quote
Old 12-06-18, 03:19 PM
  #33  
TimothyH
- Soli Deo Gloria -
 
TimothyH's Avatar
 
Join Date: Aug 2015
Location: Northwest Georgia
Posts: 12,023

Bikes: 2018 Rodriguez Custom Fixed Gear, 2017 Niner RLT 9 RDO, 2015 Bianchi Pista, 2002 Fuji Robaix

Mentioned: 182 Post(s)
Tagged: 0 Thread(s)
Quoted: 5303 Post(s)
Originally Posted by LesterOfPuppets View Post
Never seen a lockring hook spanner attachment for a torque wrench,

I just go for gutenteit
Like the manufacturers who provide torque specs on Phillips head screws.
TimothyH is offline  
Reply With Quote
Old 12-06-18, 03:50 PM
  #34  
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Posts: 31,443

Bikes: everywhere

Mentioned: 47 Post(s)
Tagged: 1 Thread(s)
Quoted: 3254 Post(s)
Originally Posted by TimothyH View Post
Like the manufacturers who provide torque specs on Phillips head screws.
Well I DO have phillips bits that I can put in torque wrenches, but...
LesterOfPuppets is offline  
Reply With Quote
Old 12-06-18, 04:09 PM
  #35  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 20,127
Mentioned: 124 Post(s)
Tagged: 0 Thread(s)
Quoted: 7082 Post(s)
I can't believe Post 30 wasn't censored.

Auto correct?
CliffordK is offline  
Reply With Quote
Old 12-06-18, 04:30 PM
  #36  
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Posts: 31,443

Bikes: everywhere

Mentioned: 47 Post(s)
Tagged: 1 Thread(s)
Quoted: 3254 Post(s)
Originally Posted by CliffordK View Post
I can't believe Post 30 wasn't censored.

Auto correct?

Ooops.

About 5 years ago I was working in a faith-based bike co-op and accidentally said that instead of lockring, in front of a preacher.

Talk about your awkward moments.
LesterOfPuppets is offline  
Reply With Quote
Old 12-06-18, 05:31 PM
  #37  
j_e_r_e_m_y
Minor Annoyance
 
j_e_r_e_m_y's Avatar
 
Join Date: May 2015
Location: Milwaukee
Posts: 184

Bikes: 2016 Soma Rush, Swobo Accomplice

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Originally Posted by Happy Feet View Post
Jeremy: All I can think is how many cubic yards of concrete it's going to take to level off that garage floor so the bike no longer shows and someone can park in there again. Did anyone try holding the bike and walking in circles to unscrew it from the cog?
We tried that, but no luck compadre. Best we can tell, the fall was so powerful that some sort of fusion thing happened and now the cog, the hub, the concrete, and the very earth itself are now bound together. But no worries, it's a two car garage, so my buddy just parks next to his fallen ride, and accepts that's he forever going to be reminded of the time he messed with the too big cog.
j_e_r_e_m_y is online now  
Reply With Quote
Old 12-06-18, 05:33 PM
  #38  
j_e_r_e_m_y
Minor Annoyance
 
j_e_r_e_m_y's Avatar
 
Join Date: May 2015
Location: Milwaukee
Posts: 184

Bikes: 2016 Soma Rush, Swobo Accomplice

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Originally Posted by Gresp15C View Post
The moral is that the bike should have had a kickstand, for the safety of the entire subdivision.
Amigo, no kickstand was gonna stop the events of that day. That's just what you get when you mess with the too big cog.
j_e_r_e_m_y is online now  
Reply With Quote
Old 12-06-18, 09:25 PM
  #39  
BoozyMcliverRot
Senior Member
 
BoozyMcliverRot's Avatar
 
Join Date: Jan 2007
Location: bradenton FL
Posts: 975

Bikes: 1991 Diamondback Master TG 1990 Trek 850 Antelope

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Originally Posted by mtb_addict View Post
How many ft-lb tight?
I'm not sure of torque spec,but definitely use some lube. You don't want things getting jammed up when your trying to get them off.
BoozyMcliverRot is offline  
Reply With Quote
Old 12-06-18, 09:58 PM
  #40  
AlmostTrick
Yabba-Dabba-Doo!
 
AlmostTrick's Avatar
 
Join Date: Feb 2006
Location: Bedrock, IL
Posts: 6,154

Bikes: 1968 Schwinn Orange Krate, Raleigh Roper road bike, Wabi Special fixed gear

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 824 Post(s)
Originally Posted by REDMASTA View Post
for every pedal stroke you will travel 62 imaginary inches on your imaginary fixieeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
Incorrect. A 62 gear inch set up will get the OP an imaginary 193 inches of travel per crank revolution. Seriously. Check the maths.
AlmostTrick is offline  
Reply With Quote
Old 12-06-18, 10:18 PM
  #41  
TMonk
Not actually Tmonk
 
TMonk's Avatar
 
Join Date: Jun 2007
Location: San Diego, CA
Posts: 10,583

Bikes: road, track, mtb

Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 718 Post(s)
all of the maths
__________________
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
TMonk is offline  
Reply With Quote
Old 12-06-18, 11:41 PM
  #42  
hairnet
Fresh Garbage
 
hairnet's Avatar
 
Join Date: Apr 2009
Location: Los Angeles
Posts: 13,117
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 306 Post(s)
Originally Posted by mtb_addict View Post
How many ft-lb tight?
I believe the technical unit is "Tight AF".
hairnet is offline  
Reply With Quote
Old 12-07-18, 12:37 AM
  #43  
Dean V
Senior Member
 
Join Date: Oct 2009
Posts: 2,136
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 625 Post(s)
If you have minimal fixie experience and get spun out on a downhill with no brakes you will crash.
It is that simple.
Just like you would have to be "simple" to put yourself in that situation in the first place.
Dean V is offline  
Reply With Quote
Old 12-07-18, 10:23 AM
  #44  
mtb_addict
Senior Member
Thread Starter
 
mtb_addict's Avatar
 
Join Date: Jun 2011
Posts: 3,167
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 2305 Post(s)
Well, I guess after reading this thread...I better upgrade the mechanical brake. I'm converting this town/cruiser bike...and it has very poor hand brakes (the back-pedal coaster foot brake does 95% of braking for me, but of course it'll be gone when I switch to FG.). I'm going to have to look for a dual pivot caliper or something. The thing is that I need super long reach...like ~80mm.

Last edited by mtb_addict; 12-07-18 at 10:36 AM.
mtb_addict is offline  
Reply With Quote
Old 12-07-18, 10:43 AM
  #45  
hairnet
Fresh Garbage
 
hairnet's Avatar
 
Join Date: Apr 2009
Location: Los Angeles
Posts: 13,117
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 306 Post(s)
You have two long reach brakes by Tektro. R559 (70mm reach) and 900A(90mm reach)
hairnet is offline  
Reply With Quote
Old 12-07-18, 02:17 PM
  #46  
BoozyMcliverRot
Senior Member
 
BoozyMcliverRot's Avatar
 
Join Date: Jan 2007
Location: bradenton FL
Posts: 975

Bikes: 1991 Diamondback Master TG 1990 Trek 850 Antelope

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Originally Posted by hairnet View Post
You have two long reach brakes by Tektro. R559 (70mm reach) and 900A(90mm reach)
Tektro also has the 356 in 70mm. It's basically the 559 with a less polished finish and crappy pads. I have both the 559 and 356,the 559s work great but I've never used my 356s. They are still new in the plastic waiting for something i can use them on. I can post side pics of them side by side if anyone is interested.
BoozyMcliverRot is offline  
Reply With Quote
Old 12-10-18, 02:31 PM
  #47  
Artmo
Senior Member
 
Join Date: Feb 2005
Location: SW Florida
Posts: 1,426

Bikes: '06 Bianchi Pista; '57 Maclean; '10 Scott CR1 Pro; 2005 Trek 2000 Tandem; '09 Comotion Macchiato Tandem; 199? Novara Road; '17 Circe Helios e-tandem

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 76 Post(s)
Originally Posted by mtb_addict View Post
What happens if I build a Fixie with 42x18 gearing? Going downhill, will my legs fall off?

This is what I run now on my coaster hub SS commuter bike.
I think I need to keep this low gearing for my commute.
Of course your legs won't fall off, but if you let the bike get away from you and you don't have the strength in your legs to back pedal to control your speed, you will lose control on a steep descent.
I used to ride fixed gear a lot in my youth, 60 years ago, but always had a front brake, as is the law in the UK and which is commonsense IMHO. Then I rode 42x16, to give about 70 gear inches, which was a good all-round gear before the trend to higher cadence.
I think you will find that a slightly higher gear than that on your coaster will be beneficial as you will have more of a forward momentum effect with the fixed gear.
Fit a front brake and stick with it!!

Good luck,
Artmo is offline  
Reply With Quote
Old 12-10-18, 02:42 PM
  #48  
mtb_addict
Senior Member
Thread Starter
 
mtb_addict's Avatar
 
Join Date: Jun 2011
Posts: 3,167
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 2305 Post(s)
Wow...I stumbled on artistical cycling on Utbue. Now I'm pumped up! I want to learn to do no hand wheelie (after I figure out how to do a regular wheelie). Looks like they use very small chainring for super low gearing, like bmx.
mtb_addict is offline  
Reply With Quote
Old 12-10-18, 03:33 PM
  #49  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 20,127
Mentioned: 124 Post(s)
Tagged: 0 Thread(s)
Quoted: 7082 Post(s)
Originally Posted by mtb_addict View Post
Wow...I stumbled on artistical cycling on Utbue. Now I'm pumped up! I want to learn to do no hand wheelie (after I figure out how to do a regular wheelie). Looks like they use very small chainring for super low gearing, like bmx.
There are TDF riders that pull a no-hand wheelie on a road bike after a grueling racing stage. No fixie needed.



I think some of the trick bikes are very specialized to the particular tricks. I presume balance is key for certain things like wheelies. I've done accidental torque wheelies on my driveway hill climb. I find them to be most uncomfortable.
CliffordK is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service