Building a quality 11t freewheel
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kudos
10 kW
miuan said:
Thanks!
hillzofvalp
100 kW
I CNC'ed a splined coupler that lets me mate a standard 11T or even 10T cassette cog to my White Industries freewheel. The two main reasons for making this were that I wanted to both avoid a derailleur because with horizontal dropouts it is redundant to have a derailleur AND to run a much smaller gear with a nice freewheel mechanism. It also let's me adjust chain alignment more easily and have arguably cheaper maintenance ($10 cog).
The reason the splines have rounded grooves is that the smallest endmill I had (1/8") would not get all the material if I didn't overcut. Worked out splendidly. Edit: too wide for cromotor. If Anyone wants one, let me know.
The reason the splines have rounded grooves is that the smallest endmill I had (1/8") would not get all the material if I didn't overcut. Worked out splendidly. Edit: too wide for cromotor. If Anyone wants one, let me know.
Architectonic
10 kW
Looks like a work of art. What kind of price are we looking at for those?
hillzofvalp
100 kW
Well, the above works, but it's only a prototype. I'm not sure what the spec is on the od of the white industries free wheels.. Also, i need to make a better design to hold the cog firmly against the splines. Fr the prototype I just used some button head screws to hold the cog down. Kind of stupid solution. A ring beneath that would've been better. A threaded piece tht requires a standard bike tool would be nice, but drives costs up
Making it all out of aluminum brings costs down, but I do not have the materials or mechanical knowledge to judge whether the splines woud hold up over time. It is a very snug fit, though.
If you are seriously interested, I can try to make a batch. I'd probably have someone else do it because using schools CNC machines it a privilege to not be abused. On that note, I'm not sure how much it would cost. Ifi had permission to run a dozen of them, I'd probably charge like $80-100usd.. But it really depends on if I can get the surface feet per minute up or not.
A bit of a catch is that whenever u want to take the freewheel off u have to take the aluminum off first.
Making it all out of aluminum brings costs down, but I do not have the materials or mechanical knowledge to judge whether the splines woud hold up over time. It is a very snug fit, though.
If you are seriously interested, I can try to make a batch. I'd probably have someone else do it because using schools CNC machines it a privilege to not be abused. On that note, I'm not sure how much it would cost. Ifi had permission to run a dozen of them, I'd probably charge like $80-100usd.. But it really depends on if I can get the surface feet per minute up or not.
A bit of a catch is that whenever u want to take the freewheel off u have to take the aluminum off first.
MAGICPIE3FOCUSPOWER
10 kW
I really don't like DNP Epoch 11T 8 speed freewheel.
To much play and noise (not even used).
And the price is way too high!
So I went back to Shimano 14T 7 speed freewheel, less play and noise.
To much play and noise (not even used).
And the price is way too high!
So I went back to Shimano 14T 7 speed freewheel, less play and noise.
kfong
100 kW
It's hard for me to not use a freewheel with 11 tooth. Already gone thru one 9 speed DPN freewheel, had to throw it out after two seasons. my current DPN seems to be holding up, it seems to be better made. I recall epoch as the module number. One of the members found a bearing to fit the big gap. If you look at the design, there is just not enough support. It causes the higher gears to push hard aganst the opening. This increases the runout overtime. I plan to do the bearing mod when I get the chance.
Kingfish
100 MW
I just replaced mine with a brand new unit and it is so much more quiet. The first one was a rattle-trap; I don't think it was well-greased. People would here the freewheel over the motor noise. Now - I only hear the motors, which also have new bearings 8)kfong said:
Although I'm with you and can't go back to a lower gear; I have several 13 and 14T Shimanos and they turn smoothly like silk.
Pity I can't use them
KFMAGICPIE3FOCUSPOWER
10 kW
I don't trust them anymore.
The sprockets will worn out earlier then all other drivetrain.
And I don't like to replace whole drivetrain because of this weak DNP Epoch freewheel.
So my solution is a bigger chainring 8)
The sprockets will worn out earlier then all other drivetrain.
And I don't like to replace whole drivetrain because of this weak DNP Epoch freewheel.
So my solution is a bigger chainring 8)
They do make 60T chainrings.. ;]
http://www.vueltausa.com/components/chainrings/se-flat-chainrings/se-chain-ring-130mm-38-60t-1.html
They sure look funny though, lol.
http://www.vueltausa.com/components/chainrings/se-flat-chainrings/se-chain-ring-130mm-38-60t-1.html
They sure look funny though, lol.
MAGICPIE3FOCUSPOWER
10 kW
Looks great mate!
Thanks for the pictures.
But my cranks are 104mm and 4 arm
I have just ordered 48T chainring hopefully this enough with 14T freewheel.
Thanks for the pictures.
But my cranks are 104mm and 4 arm
I have just ordered 48T chainring hopefully this enough with 14T freewheel.
kfong
100 kW
Unfortunately modifying the drive gears or even the frame geometry was never an option for me. I use the ebike solely for single track. Performance and all gears are needed. I often push the ebike to empty. Try riding an ebike without power in the trails. Having a big front sprocket will get mashed up during use over log piles. My Ebikes have to ride as good as a quality mountain bike in the trails. I've put the current one through many crashes, jumps and hard climbs. It puts a smile on me every time I take it in the woods. Not much I would change on this setup. http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=12654
Obviously riding only on street or commute would have different objectives.
Obviously riding only on street or commute would have different objectives.
Kingfish
100 MW
Oh now you've done it and planted a seed and I can't stop thinking about it now :lol:neptronix said:
I'll have to check that out - thanks, KF
hillzofvalp
100 kW
Slightly related.. I just made a 63T chainring for my 104mm 4 bolt MTB crank. Is turned out really nice. Running 1/8" chain with 15T white industries. Happy pedaling 25-35mph. I wheelie a lot more actually and my top end is better as u would expect. Cnced it out of 7075.
MAGICPIE3FOCUSPOWER
10 kW
Waauww well done!
Too bad I don't have the opportunity/machines/skills to that
Too bad I don't have the opportunity/machines/skills to that
DrkAngel
1 GW
DNP 11T uses a special deep removal tool.rjoe said:
It will probably work with your damaged freewheel, if you can tap it in.
DNP Epoch Freewheel Remover
MAGICPIE3FOCUSPOWER
10 kW
Does anyone knows how I can remove Shimano bearing for maintenance?
Thanks
Thanks
DrkAngel
1 GW
DrkAngel said:
Epoch and Long Yih seem to be the only produces of the DNP 11T freewheels.
Epoch 11T freewheels consistently available from NiagaraCycle.com
Long Yih 11T freewheels available (only?) from SDebike.com
See - EBikes Toolbox - Bargains! ?
Chalo
100 TW
11t freewheels are an inherently bad solution to the problem of too-low gearing. They are not a terrible thing to have when the 11t sprocket is used appropriately, which is just once in a while.
The main issue is that chain wear and friction increase nonlinearly as a sprocket diminishes in size, becoming measurably higher with each increment below 21t, and becoming problematic below 13t. On pedal bikes, the problems are surmountable because the very top gears are only used occasionally. (Also, to the manufacturers of parts, things that wear out quickly are not necessarily seen as problems. Especially when those things are seen as desirable rather than just shoddy.)
Note that track racing bikes, which sometimes reach 40mph speeds without the use of power assist, have sprockets that only go as small as 13t. Below that size, the loss of efficiency makes the option of higher gearing with smaller, lighter sprockets not worth it. And those bikes are using sprockets with wide, tall teeth-- not the kind we are discussing, with skinny stumpy teeth to help them shift more cleanly.
With e-bikes, small sprockets become a problem because the bike is run in high gears much of the time. If you run in top gear very much, you'll just chew through a lot of chains and 11t freewheels, accelerating the wear on your chainrings as you do so.
So for e-bikes, a better technical approach is to use a larger chainring rather than a smaller driven sprocket. This is a winning method in several ways: The chain articulates through smaller angles, the load is carried by more teeth, wear is distributed over more teeth, and chain tension under load is lowered in proportion to the increase in chainring diameter.
If you're not already using a 53t or larger big ring, it's foolish to pursue higher gearing through the use of a smaller rear sprocket instead. 53t cranks are so common as to be ubiquitous. A 60t ring is no more exotic or difficult to get than a freewheel with 11t high gear. So step one should be a 53t stock crankset, and step two should be a 56-60t chainring for that crank. Only after these steps are taken should a sprocket smaller than 13t be considered as an option to raise the gear ratio further.
The main issue is that chain wear and friction increase nonlinearly as a sprocket diminishes in size, becoming measurably higher with each increment below 21t, and becoming problematic below 13t. On pedal bikes, the problems are surmountable because the very top gears are only used occasionally. (Also, to the manufacturers of parts, things that wear out quickly are not necessarily seen as problems. Especially when those things are seen as desirable rather than just shoddy.)
Note that track racing bikes, which sometimes reach 40mph speeds without the use of power assist, have sprockets that only go as small as 13t. Below that size, the loss of efficiency makes the option of higher gearing with smaller, lighter sprockets not worth it. And those bikes are using sprockets with wide, tall teeth-- not the kind we are discussing, with skinny stumpy teeth to help them shift more cleanly.
With e-bikes, small sprockets become a problem because the bike is run in high gears much of the time. If you run in top gear very much, you'll just chew through a lot of chains and 11t freewheels, accelerating the wear on your chainrings as you do so.
So for e-bikes, a better technical approach is to use a larger chainring rather than a smaller driven sprocket. This is a winning method in several ways: The chain articulates through smaller angles, the load is carried by more teeth, wear is distributed over more teeth, and chain tension under load is lowered in proportion to the increase in chainring diameter.
If you're not already using a 53t or larger big ring, it's foolish to pursue higher gearing through the use of a smaller rear sprocket instead. 53t cranks are so common as to be ubiquitous. A 60t ring is no more exotic or difficult to get than a freewheel with 11t high gear. So step one should be a 53t stock crankset, and step two should be a 56-60t chainring for that crank. Only after these steps are taken should a sprocket smaller than 13t be considered as an option to raise the gear ratio further.
very nice find Nep!!
What Chalo said is all theoretically pretty much spot on.
But Chalo at the same time using track bikes as an example for human pedal output tends to distort the reality of say the typical dutch commuter cyclist, or lazy arse e-biker output!
120 cadence is ok for a few seconds or a couple of minutes but at a more realistic 70 cadence the same 40mph e-commuting speed, the gearing needs to be 170% taller!
The power transfer efficiency difference between ideal freewheel tooth count and using a compact 11t freewheels is approximately only 1.5% to 2% (from David Wilson's Bicycling Science). So given a sustainable output of 200W for a fit male (NASA) (not a drug cheat'n Texan) the difference is only an extra 3 - 4Watts lost!
Like most things, compromises have to be made.
Lets examine the facts: every recent MTB world champion
: every recent downhill world champion
: every recent freestyle world champion(down to 8T!)
Damn fools!
Like most things, compromises have to be made and and drive train efficiency is only a part of the total design package Chalo.
Stating the obvious, very cheap clusters suffer from soft "mao" metal, no proper seals, and a total lack of ability to hold onto any lubrication, and bad bearing overhangs, and most of us spend a lot more time freewheeling compared to other cyclists, and the freewheel pawls are not designed for that. Using very small wheels off road for our dumb arsed backward hub motors only puts them closer into the corrosive steel grinding muck. I find the compact clusters do not have enough space to clear grass, vines and sticks and build up around the 11T making it skip and i have to stop and clear it too often. I'm pretty sure these problems are ours for a while yet.
DrkAngel
1 GW
Chalo said:
11T Durability?
I've been running a DNP 7spd 28-11T on my eZip for 4-5 Summers, +5500 miles, with no problems or visible wear.
I do tend to pedal constantly, in 11T probably 80-90% of the time ... I cruise between 18-22mph.
The DNP 11T's, both Epoch and Long Yih are a solid steel with a heavy nickel plating.
After +5500miles there is no noticeable wear!
After cleaning, my 11T sprocket still has it's shiny nickel plating. ... Yes I do use it ...
Almost daily I push the bike to near 30mph. (Motor only is 22mph and motor assist stops at 24-25mph.)
No chain problems either. Same chain - 5 years!
Of course I do keep my chain lubricated, with "Finish Line Wet Lubricant" for the past several years.
Maybe "proper" lubrication avoids your problems?
I "clean" my chain with WD-40, then wipe down and dry with a hair dryer.
With chain nice and warm, I drizzle on the "Finish Line" and continue turning chain as I spread lubricant with a small brush.
"Hot chain" treatment seems to spread the thick lubricant into every bearing point.
After a little "run in" (couple miles ride), I wipe down the surface of the cool chain. - Don't want grit sticking to the chain "rollers".
Personal experience?
DNP 11T sprockets are nice and durable!
No apparent chain damage.
7spd 34-11T gives a great 3:1 ratio range - great for a single front sprocket!
(2008 eZip Mountain Trailz w/16T & pumped to 37V w/7spd 34-11T - 30mph capable - +3500 miles)
PS - The 9T motor sprocket, doing much more work, has no remarkable wear, ... or chain damage. ... ???
Same lubrication regime.
Chalo
100 TW
In the shop, my observation has been that folks who use the 11t much, wear it out. Cross-chaining plays a part, I'm sure, and would be less of a problem for folks on e-bikes who use their big gear instead. As for chains lasting 5500 miles-- in my experience they don't do that, even in single speed applications with perfect chainline and a 16-18t driven sprocket. Not when they are used for propulsion. Zinn says 1000 miles from a neglected chain, and 5000 miles from one kept clean and lubed on a per-ride basis. In practice I don't see the latter, perhaps because folks who maintain their chains daily don't take their bikes to the shop much.
Which is not to say I don't see chains with more than 5 kilomiles on them-- it's just that those chains have elongated past tolerable limits and wrecked their sprockets. Have you gauged your chain for elongation?
Neither downhill racers nor freestylists use their gears for steady propulsion, they both have incentives to use small chainrings for clearance, and their events are short. Nothing about either kind of bike makes sense for transportation. Road racers use 11t sprockets, but as I described earlier-- just occasionally over the course of a race. And all high level competitors will use equipment that must be replaced as often as every event, if they think it yields some small advantage to them.
My advice is to use a bigger chainring when you can, and a smaller sprocket only when you must. You'll get more speed/less effort, less wear, quieter and smoother operation, and less expense incurred by replacing parts. What's not to like?
Which is not to say I don't see chains with more than 5 kilomiles on them-- it's just that those chains have elongated past tolerable limits and wrecked their sprockets. Have you gauged your chain for elongation?
Neither downhill racers nor freestylists use their gears for steady propulsion, they both have incentives to use small chainrings for clearance, and their events are short. Nothing about either kind of bike makes sense for transportation. Road racers use 11t sprockets, but as I described earlier-- just occasionally over the course of a race. And all high level competitors will use equipment that must be replaced as often as every event, if they think it yields some small advantage to them.
My advice is to use a bigger chainring when you can, and a smaller sprocket only when you must. You'll get more speed/less effort, less wear, quieter and smoother operation, and less expense incurred by replacing parts. What's not to like?
Chalo
100 TW
Punx0r said:
That's fine if you like your chainrings like this one:
