What does this picture mean?
-
- Posts: 321
- Joined: Wed Dec 01, 2010 2:59 pm
- Location: 2113, NSW
- Contact:
What does this picture mean?
Postby jeff_o » Mon Dec 12, 2011 11:14 pm
Does this mean the rider is a strong climber? or the freehub has seen so many miles?
I'm not sure if I should be happy or sad to see a freehub like this?
I had to copy this image from another WTS thread.
- Porridgewog
- Posts: 120
- Joined: Fri Apr 08, 2011 9:10 pm
Re: What does this picture mean?
Postby Porridgewog » Mon Dec 12, 2011 11:18 pm
-
- Posts: 536
- Joined: Wed May 26, 2010 2:54 pm
- Location: Macleod, Melbourne
- Contact:
Re: What does this picture mean?
Postby pawnii » Mon Dec 12, 2011 11:26 pm
All of my aluminium freehub bodies look like this. It's usually caused by gearing down under load...like sprinting.
You can see that the freehub body isn't marked where the 3 largest sprockets are because the largest 3 sprockets are on a spider and the spider spreads the load across a wider area on the freehub.
If there is too much damage you will have problems getting the cassette on/off the freehub. I've had to file mine down to get the cassette on easily.
I don't think there are any performance issues.
2012 Scott Foil Premium
-
- Posts: 321
- Joined: Wed Dec 01, 2010 2:59 pm
- Location: 2113, NSW
- Contact:
Re: What does this picture mean?
Postby jeff_o » Mon Dec 12, 2011 11:39 pm
I din't know the freehub is alloy... i thought alloy would be too soft for this application and steel would make more sense. anyways i got the 3 largest cogs on a spider to distribute the load, but why can't they put all the cogs (except the smallest few) in a spider to spread the force more evenly and make the whole cassette even lighter?pawnii wrote:looks pretty normal for a shimano freehub. It must be a lightweight aluminium body. they seem to mark easier.
All of my aluminium freehub bodies look like this. It's usually caused by gearing down under load...like sprinting.
You can see that the freehub body isn't marked where the 3 largest sprockets are because the largest 3 sprockets are on a spider and the spider spreads the load across a wider area on the freehub.
If there is too much damage you will have problems getting the cassette on/off the freehub. I've had to file mine down to get the cassette on easily.
I don't think there are any performance issues.
-
- Posts: 536
- Joined: Wed May 26, 2010 2:54 pm
- Location: Macleod, Melbourne
- Contact:
Re: What does this picture mean?
Postby pawnii » Tue Dec 13, 2011 12:20 am
It would take more work manufacturing the cassette and more labor intensive too, so more expensive.
Steel makes more sense in terms of durability but at a weight cost.
Alloy freehubs aren't a bad thing, they last for 1000s of kms before needing replacement. They wear quicker than steel but they are light. Light = fast...in theory.
You'd probably go through a few cassettes before having to replace an alloy freehub.
The problem with most high end, light weight parts is that they tend to wear quicker like chains, chainrings, cassettes, tyres, brake pads.
For a weight weenie like myself it's worth it
It just hurts the bank account.
2012 Scott Foil Premium
-
- Posts: 5131
- Joined: Mon Apr 20, 2009 10:41 pm
Re: What does this picture mean?
Postby rkelsen » Tue Dec 13, 2011 10:16 am
No, it's not normal.pawnii wrote:looks pretty normal for a shimano freehub.
The major cause is not tightening the cassette lockring to Shimano's specification, which is 40Nm.pawnii wrote:It's usually caused by gearing down under load...like sprinting.
- sumgy
- Posts: 1487
- Joined: Tue Mar 02, 2010 10:58 pm
- Contact:
Re: What does this picture mean?
Postby sumgy » Tue Dec 13, 2011 10:51 am
Used to have this exact problem using Shimano on American Classic or Token wheelsets.
Shimano cassettes will particularly cause this due to the 3(?) outer cogs being seperate from the rest of the cassette.
As suggested by someone earlier a little filing and deburring and you are AOK.
-
- Posts: 321
- Joined: Wed Dec 01, 2010 2:59 pm
- Location: 2113, NSW
- Contact:
Re: What does this picture mean?
Postby jeff_o » Tue Dec 13, 2011 11:31 am
i just use a big wrench and tighten the cassette lockring by feel. any tips how tight a 40Nm is if you don't have a torque wrench?rkelsen wrote:No, it's not normal.pawnii wrote:looks pretty normal for a shimano freehub.The major cause is not tightening the cassette lockring to Shimano's specification, which is 40Nm.pawnii wrote:It's usually caused by gearing down under load...like sprinting.
- Kenzo
- Posts: 1680
- Joined: Sat Aug 14, 2010 8:13 am
- Location: Daisy Hill / Brisbane, Southside FTW
- Contact:
Re: What does this picture mean?
Postby Kenzo » Tue Dec 13, 2011 12:10 pm
If I remember right, simplistically speaking 40Nm is the equivalent of a 40kg weight placed at the end of a shifter with a one metre long handle (assuming little to no weight in the shifter). The equivalent downward force exerted by that weight is 40Nm.jeff_o wrote:i just use a big wrench and tighten the cassette lockring by feel. any tips how tight a 40Nm is if you don't have a torque wrench?
-
- Posts: 2631
- Joined: Tue Oct 20, 2009 10:36 pm
Re: What does this picture mean?
Postby eeksll » Tue Dec 13, 2011 12:32 pm
viewtopic.php?f=9&t=37842
viewtopic.php?f=34&t=29626
mine has not gotten any worse after I installed the kit, but my freehub was worse before I installed the kit and the free hub was new and I had definitely done less than 1000km (from memory it was probably more like 200km)
-
- Posts: 536
- Joined: Wed May 26, 2010 2:54 pm
- Location: Macleod, Melbourne
- Contact:
Re: What does this picture mean?
Postby pawnii » Tue Dec 13, 2011 12:50 pm
Yes, it is normal. There isn't a used aluminium freehub that i've seen that doesn't have marks on it from shimano cassettes...and i've seen 100s of freehubs when i used to build wheels for a shop.rkelsen wrote:No, it's not normal.pawnii wrote:looks pretty normal for a shimano freehub.The major cause is not tightening the cassette lockring to Shimano's specification, which is 40Nm.pawnii wrote:It's usually caused by gearing down under load...like sprinting.
Tightening your cassette to 40Nm won't stop this from happening. As important as it is, it has little to do with this issue at hand IMO
The issue here is when a single cog engages the freehub, it 'point loads' the freehub. Tightening the cassette won't stop point loading nor will it spread the torque load across the body of the freehub.
There are also other factors at play here also. One being the quality of the aluminium the freehub is made out of and another is the ride style of racer.
Criterium sprinters chew through aluminium bodies. Mainly from tremendous torque loads while sprinting.
Two main methods of damage are:
- the massive amount of torque produced when the chain re-engages the cog after down shifting.
- the massive amount of torque produced when the sprinter re-engages the peddle from coasting.
2012 Scott Foil Premium
- sogood
- Posts: 17168
- Joined: Thu Aug 31, 2006 7:31 am
- Location: Sydney AU
Re: What does this picture mean?
Postby sogood » Tue Dec 13, 2011 1:02 pm
To supplement... Half metre handle needs 80kg and a 25cm handle needs 160kg. Might as well stand and jump on it if the handle is short.Kenzo wrote:If I remember right, simplistically speaking 40Nm is the equivalent of a 40kg weight placed at the end of a shifter with a one metre long handle (assuming little to no weight in the shifter). The equivalent downward force exerted by that weight is 40Nm.
RK wrote:And that is Wikipedia - I can write my own definition.
- darkhorse75
- Posts: 229
- Joined: Tue Sep 01, 2009 3:16 pm
- Location: Balcatta, PERTH
Re: What does this picture mean?
Postby darkhorse75 » Tue Dec 13, 2011 1:34 pm
This isn't correct. From high school physics Torque = mass x g x moment arm g being gravitational constant of 9.8. so its closer to 8kg for a half metre handle.sogood wrote:To supplement... Half metre handle needs 80kg and a 25cm handle needs 160kg. Might as well stand and jump on it if the handle is short.Kenzo wrote:If I remember right, simplistically speaking 40Nm is the equivalent of a 40kg weight placed at the end of a shifter with a one metre long handle (assuming little to no weight in the shifter). The equivalent downward force exerted by that weight is 40Nm.
- sumgy
- Posts: 1487
- Joined: Tue Mar 02, 2010 10:58 pm
- Contact:
Re: What does this picture mean?
Postby sumgy » Tue Dec 13, 2011 1:44 pm
It is actually big wrench x pretty darn tight.jeff_o wrote:
i just use a big wrench and tighten the cassette lockring by feel. any tips how tight a 40Nm is if you don't have a torque wrench?
- sogood
- Posts: 17168
- Joined: Thu Aug 31, 2006 7:31 am
- Location: Sydney AU
Re: What does this picture mean?
Postby sogood » Tue Dec 13, 2011 1:51 pm
You are correct. There's a factor of 9.8 for the a (in F =ma). I was just concentrating on the lever length aspect which is in direct ratio.darkhorse75 wrote:This isn't correct. From high school physics Torque = mass x g x moment arm g being gravitational constant of 9.8. so its closer to 8kg for a half metre handle.
RK wrote:And that is Wikipedia - I can write my own definition.
- Kenzo
- Posts: 1680
- Joined: Sat Aug 14, 2010 8:13 am
- Location: Daisy Hill / Brisbane, Southside FTW
- Contact:
Re: What does this picture mean?
Postby Kenzo » Tue Dec 13, 2011 2:59 pm
Ah yes, and for a one metre long handle - it is about 4kg of force to the (end of the) handle to generate 40Nm on the lockring. Which actually isn't very much.darkhorse75 wrote:This isn't correct. From high school physics Torque = mass x g x moment arm g being gravitational constant of 9.8. so its closer to 8kg for a half metre handle.sogood wrote:To supplement... Half metre handle needs 80kg and a 25cm handle needs 160kg. Might as well stand and jump on it if the handle is short.Kenzo wrote:If I remember right, simplistically speaking 40Nm is the equivalent of a 40kg weight placed at the end of a shifter with a one metre long handle (assuming little to no weight in the shifter). The equivalent downward force exerted by that weight is 40Nm.
- clackers
- Posts: 2065
- Joined: Mon May 16, 2011 10:48 am
- Location: Melbourne
Re: What does this picture mean?
Postby clackers » Tue Dec 13, 2011 4:58 pm
http://www.parktool.com/blog/repair-hel ... d-concepts
-
- Posts: 288
- Joined: Mon Jul 19, 2010 9:24 pm
- Location: Brisbane
- sogood
- Posts: 17168
- Joined: Thu Aug 31, 2006 7:31 am
- Location: Sydney AU
Re: What does this picture mean?
Postby sogood » Tue Dec 13, 2011 8:14 pm
That's the real solution!ezzy wrote:Go campy
RK wrote:And that is Wikipedia - I can write my own definition.
-
- Posts: 1299
- Joined: Mon Mar 21, 2011 7:28 pm
- Location: Pikey, based on Southern Gold Coast
Re: What does this picture mean?
Postby Ken Ho » Tue Dec 13, 2011 10:01 pm
-
- Posts: 2631
- Joined: Tue Oct 20, 2009 10:36 pm
Re: What does this picture mean?
Postby eeksll » Wed Dec 14, 2011 12:30 pm
If thats the correct math, i need to go loosen my cassette rings !!!! I use a wrench thats a bit short of half a meter and I was cranking it !!!Kenzo wrote:Ah yes, and for a one metre long handle - it is about 4kg of force to the (end of the) handle to generate 40Nm on the lockring. Which actually isn't very much.
thanks for the numbers guys, Ill have a better idea of what 40 is now ie anything bigger than my 15 NM torque wrench will go.
- General Australian Cycling Topics
- Info / announcements
- Buying a bike / parts
- General Cycling Discussion
- The Bike Shed
- Cycling Health
- Cycling Safety and Advocacy
- Women's Cycling
- Bike & Gear Reviews
- Cycling Trade
- Stolen Bikes
- Bicycle FAQs
- The Market Place
- Member to Member Bike and Gear Sales
- Want to Buy, Group Buy, Swap
- My Bikes or Gear Elsewhere
- Serious Biking
- Audax / Randonneuring
- Retro biking
- Commuting
- MTB
- Recumbents
- Fixed Gear/ Single Speed
- Track
- Electric Bicycles
- Cyclocross and Gravel Grinding
- Dragsters / Lowriders / Cruisers
- Children's Bikes
- Cargo Bikes and Utility Cycling
- Road Racing
- Road Biking
- Training
- Time Trial
- Triathlon
- International and National Tours and Events
- Cycle Touring
- Touring Australia
- Touring Overseas
- Touring Bikes and Equipment
- Australia
- Western Australia
- New South Wales
- Queensland
- South Australia
- Victoria
- ACT
- Tasmania
- Northern Territory
- Country & Regional
Who is online
Users browsing this forum: No registered users
- All times are UTC+10:00
- Top
- Delete cookies
About the Australian Cycling Forums
The Australian Cycling Forums is a welcoming community where you can ask questions and talk about the type of bikes and cycling topics you like.
Bicycles Network Australia
Forum Information
Connect with BNA
This website uses affiliate links to retail platforms including ebay, amazon, proviz and ribble.