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Zoot Katz
100 kW
nutsandvolts said:
The Surly Singulator is a robust chain tensioner though I've not tried it with electric assist.
A cadence of 80 rpm is easily sustainable against a small load even for an old "cyclist". Running a 53T chainring and a 14T rear cog, with 26" wheels and 170mm cranks will give you 37.7 KmH at that cadence. Check the gear calculator at: http://www.sheldonbrown.com/gears/index.html for other values.
andys
100 W
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- May 29, 2008
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here is a product called a Schlumpf high speed drive that 20 inch small wheel bike owners sometimes run as a replacement crank that gives an insane range. You could probably still pedal at 60 KPH! Price is high though. A bigger front chain ring is the easiest way to get what you want.
http://www.pbwbikes.com/product_info.php/products_id/57
http://www.pbwbikes.com/product_info.php/products_id/57
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DahonElectric
100 W
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- Jul 15, 2008
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- 149
Nutsnbolts,
You said you have the smallest freehub available, do you mean you already have the Shimano Capreo system with a 9 tooth cog installed? I don't ride single speed, but I know that small wheeled bikes routinely use the Shimano Capreo to get big gears.
Failing that, you may also consider making your bike more aerodynamic instead, like having aerodynamic friendly wheels. You can lace the front and rear with aero rims, install aerobars so you can rest on the arms pads and be even less of a profile to the wind. You need to be aware that you are fighting aerodynamics as soon as you exceed speeds of 25kph or higher. The faster you go, the more power you need to fight air resistance. If you reduce your aero profile a bit, you will increase speed without the expense of much higher gearing. That's why race cars have a low aero profile with little engines and that is also why I converted my Dahon Mu SL to electric too. Light weight and low aerodynamic profile (the wheels are small and paired spoke at the front helps too). I could do 40km/h on the flats along Marine Drv in my town of Vancouver BC and my gearing is lower than with Dennis on his Dahon Mu SL with the 500w motor and a Shlump drive. However, I cycle with a very high cadence of 100 rpm on the flat..
You said you have the smallest freehub available, do you mean you already have the Shimano Capreo system with a 9 tooth cog installed? I don't ride single speed, but I know that small wheeled bikes routinely use the Shimano Capreo to get big gears.
Failing that, you may also consider making your bike more aerodynamic instead, like having aerodynamic friendly wheels. You can lace the front and rear with aero rims, install aerobars so you can rest on the arms pads and be even less of a profile to the wind. You need to be aware that you are fighting aerodynamics as soon as you exceed speeds of 25kph or higher. The faster you go, the more power you need to fight air resistance. If you reduce your aero profile a bit, you will increase speed without the expense of much higher gearing. That's why race cars have a low aero profile with little engines and that is also why I converted my Dahon Mu SL to electric too. Light weight and low aerodynamic profile (the wheels are small and paired spoke at the front helps too). I could do 40km/h on the flats along Marine Drv in my town of Vancouver BC and my gearing is lower than with Dennis on his Dahon Mu SL with the 500w motor and a Shlump drive. However, I cycle with a very high cadence of 100 rpm on the flat..
Mark_A_W
100 kW
I'm sorry, you run out of gears at 35kmh??
My mountain bike based ebike, with it's rear gears intact (front motor), with the 9th gear being an 11 tooth rear sprocket, and 44 tooth ring gear, is good to 47-50kmh. After 50 I can't keep up.
You need a smaller rear sprocket. My brother's rear hub motor e-bike has a Shimano 7 speed freewheel with an 11 tooth sprocket too...or maybe 12, but it's good to 45kmh+.
Or fit a 52 tooth ring gear.
Something is not right.
My mountain bike based ebike, with it's rear gears intact (front motor), with the 9th gear being an 11 tooth rear sprocket, and 44 tooth ring gear, is good to 47-50kmh. After 50 I can't keep up.
You need a smaller rear sprocket. My brother's rear hub motor e-bike has a Shimano 7 speed freewheel with an 11 tooth sprocket too...or maybe 12, but it's good to 45kmh+.
Or fit a 52 tooth ring gear.
Something is not right.
StevenR
100 W
I would think the bigger ring would be your solution.
I run a C'lyte 5303 that will do 56 kph (35mph/.62 right?) with a 54x11 max gear on 26" wheels and I run outa gears.
Does anybody know where I can get a 60T (or whatever- just BIGGER) front ring to mount on the old 5 arm spider (non-compact drive) crank?
I run a C'lyte 5303 that will do 56 kph (35mph/.62 right?) with a 54x11 max gear on 26" wheels and I run outa gears.
Does anybody know where I can get a 60T (or whatever- just BIGGER) front ring to mount on the old 5 arm spider (non-compact drive) crank?
kbarrett
10 kW
Get a 56 tooth front ring ... with a small single gear freewheel and a surly singulator, you will have plenty of umph.
You could get a 62 ... but you may not be able to get it started without an electric assist.
With a 56 front, and the small 14 in the back, I have no trouble with insane cadences while the power is on with my 'bent.
You could get a 62 ... but you may not be able to get it started without an electric assist.
With a 56 front, and the small 14 in the back, I have no trouble with insane cadences while the power is on with my 'bent.
ericslai
10 mW
Here you can find chainrings up to 73 teeth.
http://www.hostelshoppe.com/cgi-bin/search.pl?category=605000
http://www.hostelshoppe.com/cgi-bin/search.pl?category=605000
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DahonElectric
100 W
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NutsNBolts,
I think part of your chain problem is probably due to a chainline problem. I see that you are running a mountain triple (probably a 104/64 BCD- Bolt Circle Diameter) crankset and you are using the outer most chainring , the 48T. If you are running a 48T/16T, your chainline will really be running at an extreme angle and very likely to pop out. You actually need to have it closer to the bottom bracket to make things work better.
In terms of the sizes of chain rings you can use is determined by the BCD of your crankset. There are 3 sizes, 104, 110 and 130. 130mm is for road cranks, 110mm for track or compact type crankset, whereas the 104mm is for mountain bikes. The smaller the BCD, the smaller the granny chain ring you can install. In your case, you want the largest chainring, so you would need to replace your current crankset to something like a single speed crankset (a 110mm) and then buy a custom chainring of your preferred size. When you replace your crankset, you will also need to replace your bottom bracket, because a single or double crankset uses a narrow spindle BB rather than the triple you have, which accommodates 3 chain rings. Besides, your chain line wouldn't be right anyhow if you insist on keeping your current bottom bracket.
Hope this helps.
I think part of your chain problem is probably due to a chainline problem. I see that you are running a mountain triple (probably a 104/64 BCD- Bolt Circle Diameter) crankset and you are using the outer most chainring , the 48T. If you are running a 48T/16T, your chainline will really be running at an extreme angle and very likely to pop out. You actually need to have it closer to the bottom bracket to make things work better.
In terms of the sizes of chain rings you can use is determined by the BCD of your crankset. There are 3 sizes, 104, 110 and 130. 130mm is for road cranks, 110mm for track or compact type crankset, whereas the 104mm is for mountain bikes. The smaller the BCD, the smaller the granny chain ring you can install. In your case, you want the largest chainring, so you would need to replace your current crankset to something like a single speed crankset (a 110mm) and then buy a custom chainring of your preferred size. When you replace your crankset, you will also need to replace your bottom bracket, because a single or double crankset uses a narrow spindle BB rather than the triple you have, which accommodates 3 chain rings. Besides, your chain line wouldn't be right anyhow if you insist on keeping your current bottom bracket.
Hope this helps.
StevenR
100 W
THnks for the help. That link to hostelshope is just the ticket. 62x11 here I come!
dennis
10 W
kbarrett said:
I have tested the Schlumpf HS drive a little over 500 miles now. I feel it was well worth the cost for this electric bike junky that likes to pedal alot. The dual speed push button planetary gearing enables the rider to switch from an extremely high gear(130T front and 14Tback) back to a normal gear(52T front and 14T back) again with a click of the heal that depresses the button on the crank. When I get caught in high gear and have to stop quickly, I just have to click the button with my heal and I am back in normal gear. No hard starts that can hurt the knees. You really have to try it to understand what I mean. see article: http://www.utahtrikes.com/ARTICLE-33.html
There is nothing like it if you are into pedaling up and downhills continuously. I have not found a hill I can not pedal down even when I was traveling at above 40 mph. At that speed though due to wind drag and the cogging hub motor, I can only manage burst of pedal power input of about 3-9 mph above the coasting speed for a short duration.
Here's a picture of one of the test hills. I was able to coast down and pedal at about 40 mph with a cadence in the high 70 to 80 range at high gear (130T front and 14T back).
kbarrett
10 kW
Nuts and Bolts: Get a better crankset ... that one you are using is kinda funky ... no way to easily swap rings.
Here's a good choice. I think 110mm bolt spacing will be easiest to deal with.
Here's a good choice. I think 110mm bolt spacing will be easiest to deal with.
kbarrett
10 kW
dennis said:
I want one. I hate you. Now you are starting to cut into my firearms budget.
dennis
10 W
Glad to help a fellow electric assist pedaler. Your Heizman freewheeling geared hub would be a great fit for the Schlumpf HSD. With my Bionx kit, the non freewheeling cogging hub motor really limits the bike's top speed performance. The 500W HS hub motor is rated at 480rpm at 36Volts and acts like a speed limiter. The sweet spot is at 26 mph and the cogging becomes more intense the higher I exceed that speed. Maxium flats speed with intense pedaling is at 30 to 31 mph. If I had a freewheeling geared hub motor, I'm sure I could manage a few more mph top speed with the high gearing.
Zoot Katz
100 kW
nutsandvolts said:Thanks for all of the suggestions!
I suppose I should pay more attention to what I actually have!I just asked the guys at phat moose cycles to put a single speed freewheel on, didn't even ask what product it was, pic is below, looks like it has 16 teeth.
On the front, I only use the largest original chainring for the mountain bike (no derailleurs), appears to have 48 teeth.
So 48T front 16T rear, and this is a 24 inch rear wheel, the front (and the original rear) wheels are 26 inch. So part of the problem is the 24 inch wheel, although I'm liking this 24/26 combo, the bike accellerates nicely and pulls up hills great running 56V with 24 inch drive wheel. However, I have to pedal like mad at 35kph to even have an effect (geared way too low!), and speeds above that fughedaboutit.
I continue to be baffled by the complexity of bike part standards, in this case I have no idea how to even identify a proper larger chainring that would fit. Perhaps I should wait anyways, because I want front suspension and disk brake, and it probably doesn't make sense to buy just a fork, I would be better off buying a used mountain bike. But anyways, there seems to be lots of types of chainrings, the sizing/numbering of which I don't understand. Is there some good sites that describe these things, or can anyone tell me how to pick a large chainring (like 62T) that would fit?
From the pic it looks like your chainrwheels are riveted. IOW, you're hooped unless you change your crank. Your 48/16 gearing will give you only 22.4 KmH @ 60 rpm. Even if it was possible with your present crank, 62/14 at the same comfortable cadence would only be 33.1 KmH. A cadence of 120 rpm is hard to maintain for long under a load and without some form of foot retention but would yield 44.8 KmH with your present gears.
Bookmark Sheldon Brown's site for answers to bicycle related question you've not yet thought to ask.
Gear Calculator.
http://www.sheldonbrown.com/gears/index.html
Chainwheels
http://sheldonbrown.com/harris/chainrings.html
The only times in my life I'd ever broken a chain was when I started buying the cheapest kind ($9.00) After breaking two of them I upgraded to the twelve dollar ones and haven't broken one since. For 15 bucks I'll sometimes get the nickel plated ones at MEC. My favourite lubricant is plain old winter grade bar oil at ~550 Km intervals maybe five times before tossing them in the scrap bin. Chains are cheaper to replace than cassettes or freewheels and a worn chain will eat a new cog. Seven speed freewheels usually survive 4 or five new chains before needing to be replaced. Chainwheels last longer because they have more teeth so spread the load.
Running a single speed you can't afford your chainline to be skewed. You'd probably be better off putting the largest available chainring in the middle position on a triple chainring crank. . . . Except when chainrings get larger they have a tendency to hit the chainstays. You'll notice many, if not most, right chainstays are peened to accommodate the chainwheel. Any competent punk on a tall bike can show you how that's done.
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trappermike
100 W
I talked to the local(very knowledgable)bike mechanic.He told me that going from the 48t chainring on my bike to a 52t+ could cause problems in shifting etc.(Good only for road bikes designed for them) So I go to an 11t rear sprocket and thats it,I can pedal with the motor to about 45k....
trappermike
100 W
I think I have a 48t front sprocket,and had a 14t rear(Low) I can almost peddle up tp the bike's top speed(38-40kph).Now I have ordered a rear sprocket,11-28 w2hich should let me peddle with the bike a higher speeds. The local bike mechanic is very experienced and honest. He says there could be some shifting problems when going to a bigger front sprocket,like 52.
So I'm going from my low sprocket from 14t to 11t.
I think that should give me more peddling speed without more problems.... time will tell I guess.
So I'm going from my low sprocket from 14t to 11t.
I think that should give me more peddling speed without more problems.... time will tell I guess.
This is a question I would like to know as well. I am new to e-biking and use my bike alot more now. Instead of using 4 tankfulls of gas a month in my car I use maybe three. So I know I am saving some money.
Currently I have a shimano 48t final drive chain ring with a 13t rear spocket driving the back wheel. When I get the electricity flowing wide open I can get up to 21 - 24 mph.
At that speed, the final drive pedal 48/13 is near the peak and I am pedalling for all I'm worth. I have been looking at upgrading the final drive chainring to maybe a 52t or 56t but have no idea of how that might affect my upper speeds or exhaustion levels on longer rides. Also I have no idea of which manufacturers have this size chainring. Does anyone have any suggestions or ideas on if I should do this or how to do this?
Email me and let me know - thanks.
Currently I have a shimano 48t final drive chain ring with a 13t rear spocket driving the back wheel. When I get the electricity flowing wide open I can get up to 21 - 24 mph.
At that speed, the final drive pedal 48/13 is near the peak and I am pedalling for all I'm worth. I have been looking at upgrading the final drive chainring to maybe a 52t or 56t but have no idea of how that might affect my upper speeds or exhaustion levels on longer rides. Also I have no idea of which manufacturers have this size chainring. Does anyone have any suggestions or ideas on if I should do this or how to do this?
Email me and let me know - thanks.
docnjoj
1 GW
52 tooth is standard large ring on road bikes. Check town dump or Goodwill. Bigger costs more! Harris Cyclery or online!
otherDoc
otherDoc
