Diamondback OverDrive 27.5 "RidgeRunner"

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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Alan B   100 GW

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Choosing between Hubmotors and Mid-Drives

Post by Alan B » Jul 25 2016 10:00am

Recently a friend considering an ebike asked me some questions that I thought would be worth sharing here. What follows is fairly abbreviated, whole books have been written on this topic. Here I will boil it down.

Prospective User Question:

Take a look at this web page, which is very hard on mid drives ! I'm interested in your comments.

http://www.pedegoelectricbikes.com/faq/#hub


My Summary of Pedego's page:

Hubmotors are best for most people.
Most mid drives are 250W, Pedego humbotors are 500W.
You pay more and get less with mid drives.
Maintenance is higher with a mid drive than a hubmotor.
Mid drives are complicated and you have to shift.
Hub motored bikes are more pleasant and easier to ride.



My response to my friend:

So far I've built all the types, medium size DD (direct drive) hubmotor, large DD hubmotor, geared hubmotor and now mid drive. They all have their advantages, and I am not throwing any of them away, they all have their use cases. You should pick what you want to do based on your needs. What follows is based on my experience building a small fleet of ebikes and using them for commuting, transportation, exercise and fun.

Now Pedego is in business to sell and support a lot of ebikes, and they have their own issues to deal with. The biggest bike manufacturers are going mid drive. Bosh is one example, and there are a number of others. Why is that? Mid drive ebikes are the lightest and have the widest range of application, and are the most bike-like system. In countries with low power limits (most of the world), mid-drives make the most of low power. However hubmotors are also useful ebikes.

What bike are you going to convert? What are you going to do with it? That matters and guides what is the best choice for you.

Direct Drive (DD) hubmotors are best for high mileage commuting. They make a heavier bike, and if you have steep hills you need a BIG hubmotor. You can't beat DD hubmotors for simple reliability. But it takes a lot of copper and magnet material to have adequate torque, making a hubmotor heavy and if you get on a really steep hill it may overheat, burn up or just fail to get up the hill. The DD's regen capability is wonderful for those big downhills, especially if it is variable regen (which depends on the controller). Large DD hubmotor equipped bikes tend to be heavy and more Moped-like machines. Some folks are annoyed by the poor coasting of the DD hubmotors, as there is a little bit of magnetic resistance to rolling in the motor. A large DD hubmotor can handle a lot of power.

Geared hubmotors are smaller and lighter, but the gears are fixed (*). They have a clutch and coast like a regular bike. And you lose regen. Which means the brakes have to work much harder. They are more limited in motor power (due to a smaller motor with a more difficult heat dissipation path), require more maintenance (than DD hubmotors), and climb hills a little better than a low power DD hubmotor (but not as well as a high power DD hubmotor :) ). They keep the bike fairly light, but not as light as a mid drive. They are fairly expensive and require periodic maintenance inside the hubmotor of the gearing and clutch system. If you have some steep hills you'll probably need either a large DD hubmotor or a geared hubmotor to give enough assist to be useful. The large DD hubmotor will reduce the room you have available for gearing, so the geared hubmotor may be a better choice if you still want a wide range of pedal gears. Geared hubmotors can't handle quite as much power (as DD hubmotors) due to their size and to the heat conduction path.

With either type of hubmotor you have to deal with absorbing the reaction torque, which can be quite tricky on some bike frames. You have to make or buy a new wheel and fit a big flatted axle into the bike's dropouts. Not all frames are easy to fit this big axle into, and you may have to hack the frame and file the dropouts (or make custom units) to make it work. Not a problem for a manufacturer, but for you and me, a lot of fiddling to get it all together. If you put the hubmotor in the rear (the best place for a motor) then you also have to deal with the gearing, and the width of the motor, and the brakes. Disc brakes are problematic with alignment and clearance issues to sort out. Rim brakes not so much, though the new rim has to match and have rim braking surfaces. And if you make the wheel yourself you have to deal with spokes of special lengths, and difficulty getting the offsets right, etc. If you put the hubmotor in the front wheel you need to be concerned about torque reaction, fitting the front fork lips, and the loss of front suspension effectiveness if you have that. The safety implications of front wheel fork, dropout or mounting failures are significant, an ugly crash and a pair of broken collarbones may result from a problem here.

With either hubmotor you have to deal with changing tires. It is MUCH harder to get a motor wheel off and back on, and it is HEAVY to work with. Not something you want to do on the side of the road. Not at all like changing a tire on a regular bike wheel.

Hubmotors do have one big plus - chains last a lot longer. I just measured the chain on my Borg, a hubmotor bike with getting toward 10k miles on it, and the chain wear has not reached the 0.75% chain replacement point. Nice for a commuter, just charge and ride, and replace the occasional worn out rear tire. I did find that the freewheel wore out at about the same rate as the rear tire, but they aren't expensive. Lubing it did seem to help, and just replacing it when the tire was off since it is not that fun to remove the motored wheel.

Mid drives come in many flavors. Some require special frames and batteries like Bosch, a very expensive proprietary setup. Fine for a big manufacturer, but small manufacturer's (perhaps like Pedego) can't deal with all that easily. The particular mid drive that I'm working with here is designed to be a drop-in system for regular bikes. It is easier to put on a bike than a hubmotor. There are very few problems to solve, providing that the bottom bracket shell is one of the standard types that the Bafang drives are made for, and providing that there is space for the motor to ride in front of the downtube. Some new frames are not a good fit, but most older (and many new) frames are fine. If the downtube curves and comes into the front of the bottom bracket shell it can force the motor to ride lower than I'd like, for example.

You get to keep all your rear gears, and it gives the handy option of a rear internal hub (a sturdy one is required however). I have nine on my new bike, a huge range from 36 to 12 teeth. I had to give up the triple chainring in front, as the BBSHD only has one ring, but I still have a very large range, enough that I can still ride the bike without the motor running. It has no regen though. So I picked a frame with dual hydraulic brakes and put bigger discs on, so I have plenty of braking there. Some mid drives do support more than one chainring, so if that is important to you look for it. Chain wear is greater on small cogs, best to use 14 or more teeth and keep the chain speed high and tension low (and keep it clean and well lubricated).

The mid drive puts more wear and tear on the chain and cogs. Not much of a problem, but you do have more drivetrain maintenance if you ride a lot. For daily commuting I would go with a DD hubmotor. Just like I built initially. But for occasional use you can just buy a new chain every 2000 miles or so (I have 1300 miles on mine now and I don't see much wear, according to the chain wear gauge). How many miles are you going to ride? Pedal bike chains generally wear out in 2000-3000 miles, though folks often ride them much longer and then are faced with a more expensive replacement of not just the chain but also the cogset and perhaps even the chainring(s). Get a chain wear gauge and replace the chain before the worn chain ruins the other elements in the drivetrain.

The power handling of a mid drive varies over a wide range, depending on the design. The small mid drives such as Bosh don't handle a lot of power, but they take advantage of the gearing and produce a lot of torque at low speeds. Larger mid drives like the BBSHD with higher power produce a lot of torque at higher speeds. The most powerful mid drives (such as Zero motorcycle motors) produce too much torque for bicycle chains and gears and need to use a motorcycle type left hand drive chain that is much tougher than bike chain. High power mid drives that drive through the bike chain can produce wear and rapid failure of bike chain and gearing. Bike gearing is designed to handle a couple of kilowatts peak and a few hundred watts average. Exceeding that increases wear and chances of short term failures.

There are also some gears inside the BBS, pretty similar to what is inside the geared hubmotor. They don't require much maintenance, but might require some grease every 5000 miles or so.

As I have experienced, the mid drive will easily handle the STEEP stuff. The bike is light, like a bike. Pick up a hubmotor ebike. They are not very light. Hubmotors are heavy (or the light ones have little torque). The geared hubmotors are lighter, but you still end up with a lot of weight in the motor wheel which is not a good thing for balance and inertia. Mid drives are balanced, and you can put one into a dual suspension bike and really handle rough terrain. All the major bike manufacturers are going mid drive with their electrics. The manufacturers that are making hubmotor bikes are the ones who didn't make bikes before. There will always be exceptions, but this is generally the case.

The mid drive is much easier to install (assuming we are talking about a good bolt-on kit like the BBS02 or BBSHD). Take the old crank out, Clamp on the new crank/motor, Mount a battery, display and plug in the wires. You can do a throttle, or not with the BBS02 or BBSHD and just the pedal assist controls. No wheel to build or pay for. No fat axles to fit. No torque arms to figure out. No new gearing and disc brake clearances to sort. No brakes to match up. Changing a tire is quick and easy, QR axles still work. Buy some chain lube and a chain wear gauge, keep it clean and lubed, and replace it before it wears out your cogs.

Hubmotors are simpler to operate. Just mash the throttle and go. With a mid drive you get to think about shifting again. But consider this - If you have a hubmotor and a mid drive that are both using the same power, and reaching the same top speed, and if your bike has a 12-36 tooth range sprocket, then in the lowest gear the mid-drive will generate THREE TIMES the torque that the hubmotor can generate, at the same power level. The difference is, on the really steep stuff, the hubmotor will be straining and getting hot, and the mid drive will be loafing and staying cool. I find if I put my BBSHD on this bike into third gear and leave it there, I can ride it like a hubmotor with a 20mph top speed, and lift the front wheel if I'm not not careful with the strong torque. If I need to climb steeper, I still have two gears to downshift into. If I need to go faster I have six gears to shift up into. But I can ride it without shifting, and the motor doesn't get hot.

The riding experience is different. Riding with a hubmotor is like driving an automatic transmission. Just twist the throttle and go (or pedal for pedal assist systems). The mid drive is more like driving a manual transmission. Shift up, shift down, think about shifting before you stop, (with an internal geared hub you can shift while stopped), letting off the throttle, reducing pedaling, or using a brake or gear shift sensor to reduce power while shifting. I can simulate the hubmotor driving experience with the BBSHD by putting it in the appropriate gear and leaving it there. But shifting is normally part of the mid drive experience that is less important with the hub motor. Plus the small motor mid drives really need to be shifted to have adequate torque. So they are busier to ride.

And whatever you choose, have fun! Let's go ride!

(*) There is at least one small hubmotor that has two speeds internally. This allows the small motor to stay cool while slowly climbing steep hills, however it still has hubmotor disadvantages like torque arms, building a wheel, changing flat tires and difficulty of fitting the disc brake, but for some users it could be a good choice with a fairly light bike and low chain wear.
Last edited by Alan B on Sep 26 2016 2:18pm, edited 6 times in total.

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Re: Diamondback OverDrive, my RidgeRunner

Post by fechter » Jul 25 2016 3:56pm

Alan B wrote:Thanks for the heads-up.

It is tricky to get the right URLs from Google that work for everyone. The pics looked fine to me so it is hard for me to tell there's a problem. I fixed them and verified from another account. Please let me know if it works for you now.
Looks great now.

The little battery is pretty amazing. Perfect for a small stand-up scooter.
"One test is worth a thousand opinions"

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Jul 27 2016 9:54pm

Just took the RidgeRunner for an evening spin around our hilly neighborhood to check out the new display. Speed seems to be right on, compared to the Batt-man. Nice. The amp meter reads 30.0 whenever I nail it. Amazingly right on 30.0. The display is not very bright when outdoors. The Batt-man is much easier to read in bright light. But not as pretty in monochrome. However the DPC-14 was readable enough, though I didn't test it in noontime sun, it is evening here now and the sun is low in the West.

The voltmeter tracked with the Batt-man once it dropped off the limiting value. Calibration is good there too.

Updates:

One other thing I forgot to mention earlier. They have made a huge improvement in maintainability by adding a Bafang style plug between the display and the pushbutton control, so it can be replaced without changing the display. These pushbuttons get a lot of wear and tear, and I've had one that went bad already. Being able to change it without changing the display is a huge improvement.

Another smaller note is the handlebar bracket is the same, so I was able to swap displays without changing the bracket, which on my bike is best done by loosening the handlebar and sliding it sideways so the clamps don't have to be bent to clear the FAT central part of the handlebar. Another great convenience.


The DPC-14 does just about everything one could want, except from giving integrated current (amp hour) readings. It is an excellent display, best of the Bafang's so far.

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Luna Mighty Mini Battery

Post by Alan B » Jul 29 2016 11:23pm

Image

Image

Image

This battery is a small powerhouse. That's an off the shelf underseat bag from Amazon. There's room left for a small multi tool, tire levers and patches. Maybe even a CO2 inflator. Over 300 watt hours, at 15 watt hours per mile that's 20 miles, or at 30 watt hours per mile that's still 10 miles.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 25 2016 8:57pm

Ride Report

A mixed group of almost a dozen riders and machines gathered south of the China Camp State Park entrance at a dirt parking area alongside the bay. We set out on the pavement and after a short distance ramped up to the shoreline trail and headed Northerly up the ridge overlooking the road. The trail was firm dirt with some gravel and rocky spots and the weather was comfortable for this day, though it heated up a bit later.

We paid our entry fee at the park's edge and continued up the Shoreline trail. Along the way we picked up another rider who had parked further North and rode south on the trail to meet us. The trail wound through the forest and we glided by deer and wildlife who hardly noticed us, and other hikers and bicyclists who certainly noticed us. There was some recognition that our bikes were electric, though everyone was friendly or at least not loudly negative. Judging by the mountain bikers we encountered, we were not going faster that they were, except perhaps on some of the climbs, but they were crazy fast going down on those same trails, faster than I was interested in riding at least.

At some point we turned onto a different trail and started a steeper and occasionally rough ascent, ending at the Nike site. The concrete pad there was a few inches higher than the trail and one rider failed to see that due to the shadowing and received a snakebite flat, so we lounged and visited at the top for awhile during the repair.

On the way down the speeds increased, and there was one minor mishap where the rider over-braked at a drop and did a slow tumble resulting in a scraped elbow. He'll feel it for a few days, but it did not appear too serious.

Bosch based mid drive bikes dominated the group, plus a pair of Luna mid drives, a BBS02 and my BBSHD, and a Cromotored fat tire bike. The Cromotor rider was short on time so he didn't complete the steeper visit to the Nike site portion of the ride.

So how did the RidgeRunner do?

One very important feature of a ride for my part - no crashing, no flats and it didn't run out of juice. The new Maxxis Ikon and Ardent Race tires were faced with many challenges, and they came through and brought me home. I had a few near falls, but that is my own skill. I managed to save them, and I don't think I pulled any muscles doing so. One previous ride I pulled a little muscle that bothered me for about six months, making it difficult to cross one leg - and put on socks and shoes. This time I'm tired but don't feel any stressed muscles. But it may take a day or two to really know. Tennis on Tuesday might be telling.

I used less than half of the 24AH in the pack, so I had lots of go juice left, and traveled more than a mile per amp hour in a bit under 4 hours of trail time, all stops included. The motor reached a warm, but not quite hot temperature, a bit cooler than the BBS02 the other rider was using, as you might expect.

The BBSHD did a superb job. I don't think I used full throttle, and the PAS was good, though I'd like to reduce the aggressiveness of PAS a bit. I was using throttle to reduce the PAS thrust a lot, and never needed above PAS level 2. The bike could keep up with anything there on the uphills, though my confidence and skill in handling the rough terrain held me back at times.

The Tektro Dorado brakes were excellent in every respect except the noise and vibration in the rear brake, it is doing a good job of informing the neighborhood of my approach, to at least my annoyance. Need to fix that.

The Topeak cantilevered rear rack is a problem. It will not stay straight. It needs some struts as I did on the Borg to stiffen and restrain it. I was introduced to an interesting rear rack from Thule - a pannier rack that attaches only to the seat stays and can carry up to 55 pounds. Very interesting design, but it might not work for me since I have a brake line running on top of the seat stays. But I've considered making some aluminum struts to work in a similar way, custom to fit this bike and rack, so the rack would have the seat tube plus the seat stay support.

The GoPro mount kept rotating down. I had it on the front fork. I have a lot of video of my feet from the rotated, then rear facing upside down camera. The lens was so dusty I don't know if there is any useful video (what I've looked at thus far seems ok as far as the dust goes). A better mount is indicated. I've had the best luck running the cameras inverted, they don't tend to rotate then. :(

The bike is also very dusty, another cleanup chore to add to the list. :)

One kamikaze flying squirrel came down the hill in the air, and went across my path, right in front of the camera. Not sure if the video captured much, he was moving like a grey cannonball, and he may have taken a bounce off the front of my front tire. He was really close. Found the video, still image follows in post below.

A full suspension mountain bike would likely be better for this terrain, and some of the other bikes were FS. I've considered moving my parts over to a FS bike, but cheap ones aren't good, and good ones aren't cheap. Plus they are heavier, hard to have a good rack on, and difficult to fit a decent battery into.

The RidgeRunner could use a few tweaks, but it is a good machine.

Ride Safe!
Last edited by Alan B on Sep 26 2016 1:11pm, edited 3 times in total.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 25 2016 9:45pm

Image

At the Nike site, performing surgery on another rider's pinch flat, on a convenient table. They were very happy I had a spare tube along.
Last edited by Alan B on Sep 26 2016 2:19pm, edited 1 time in total.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 26 2016 1:08pm

I reviewed some of the video and found the Kamikaze Flying Squirrel at 0353:

Image

The contrast is low due to the dust on the lens, it appears that the squirrel bounced off the front of the tire. Ebikes go a little faster than pedal bikes so perhaps he needs to recalibate for them. :)
Last edited by Alan B on Sep 27 2016 10:35am, edited 1 time in total.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 26 2016 1:44pm

san pedro ridge nike site mvc-2748.jpg
san pedro ridge nike site mvc-2748.jpg (17.48 KiB) Viewed 2815 times
The Nike Missile Site

More on these sites: http://acme.com/jef/nike/

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Re: Diamondback OverDrive, the RidgeRunner

Post by fechter » Sep 26 2016 2:19pm

Great report. It's quite a climb to the Nike missile site. I came up the opposite way on the Scettrini fire road one time. That was pretty brutal but it's outside the state park so I saved $3.00. I would gladly pay the $3.00 to go through the park next time. I know what you mean about the dust. It's like riding through a big pile of flour.

I seem to keep running into homeless encampments on the routes I take.

If somebody wants to do a flatland ride, McInnis park through Las Gallinas Sanitary District to the Hamilton Wetlands Preserve is a nice ride that goes along the bay shore. So flat you don't need a motor.

Another nice steep climbing ride is Chicken Shack fire road that starts just off US101 at the Nave Drive exit or the Terra Linda - Sleepy Hollow Preserve trail (includes part of the 680 Trail).
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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 26 2016 2:23pm

We should plan some group rides.

I met Nick from Sausalito on this ride, he was riding a BBS02 on this ride, he has a fleet of ebike builds including some 2WD setups.

On this ride we bypassed most of the China Camp history, it would be nice to do a ride covering the more historical areas along the bay, probably a much easier ride, too.

We didn't encounter any homeless encampments on our route.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 29 2016 7:48am

I applied some grease to the back side of the brake pads, as was suggested to reduce the rear brake howling.

It did change, but it did not solve the problem.

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Upgrade Suggestions

Post by Alan B » Sep 17 2019 8:51am

So I'm thinking about upgrades on this bike. Any suggestions or comments? Here are a few ideas I've thought about:

1) Rohloff speedhub IGH (with BBSHD), 14 speed, twist shift

2) PhaseRunner and CA3 for BBSHD

3) Battery improvement - lighter and smaller, options for different capacity/range. Triangle pack is nice but heavy, be good to have other options for most trips which don't need it. And a portable or built in charger for those trips where it is useful.

4) Torque sensor - is there a torque sensor that will work on a BBSHD?

5) Rack improvements - strengthen, stabilize

6) Kickstand??

7) Fix rear brake noise

8) Throttle alternatives - drop it, stealth it, ??

9) ??

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Re: Diamondback OverDrive, the RidgeRunner

Post by Voltron » Sep 17 2019 11:50am

Re brake howl, deglazing the pads with a file sometimes helps. No idea of it works on bike brakes the same way, but the anti howl compound for car disc brakes is more like a very weak RTV type goo, like instant gasket quick dry rubber, so the pads don't vibrate against the pistons, instead of grease.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 17 2019 7:12pm

I should try sanding them, though they did this from new. Haven't messed with it lately, bike has been stored.

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Re: Diamondback OverDrive, the RidgeRunner

Post by E-HP » Sep 17 2019 7:32pm

The scenery from the photo album from your original build made me start mapping out a loop in my mind for my a future ride. Up the hill, drop down through the Tilden Park entrance, up the trail to Inspiration Point, then ride ridgeline and exit out the west side by the Alvarado trail head. The nice thing is, no car involved, whereas on my mountain bike, I'd transport my bike from my house to Tilden, and now it's all by ebike :thumb: Beautiful this time of year.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 17 2019 8:17pm

It is a wonderful park to ride in. I had some trouble with gates which can be a challenge to navigate with a heavy ebike, and was concerned about hassle from Rangers or anti-E locals, but it didn't happen.

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Re: Diamondback OverDrive, the RidgeRunner

Post by E-HP » Sep 17 2019 8:29pm

Same here, the last time I rode there. Everyone was pleasant, but I think it was a weekday. I think it’s the open space, so less sharing of the trail necessary. I may need to build a mid drive for some of the really steep hills though.


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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 17 2019 9:16pm

The dual-drive Bonanza 9C/BMC does very well on the steep stuff, as does this BBSHD.

The dual drive is heavier, but is just point and go. No shifting required, and terrain instability is much less important. The BBSHD is lighter and requires a little more planning to be in the right gearing, and slips and slides more. It is probably more likely to flip over backwards because the dual drive self limits, as soon as the front lifts half the torque goes away whereas the mid drive will just keep on torquing and rear traction increases when the front lifts. Be careful.

Light weight is a big advantage when having to wrestle through gates and other obstacles.

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Re: Diamondback OverDrive, the RidgeRunner

Post by E-HP » Sep 17 2019 9:37pm

Good advice. I've noticed that I need more practice in technical sections using an ebike with respect to controlling the power. But I've also noticed that since the power is smoother than when pedaling hard, I'm not losing rear wheel traction or lifting the front wheel as much on a steep climbs.

The last time I rode those trails, there were a bunch of cows standing around on the path. They just looked at me while I squeezed between and around them. I guess they don't mind sharing the trail, but not going to lift a hoof to let an ebike pass by.

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 17 2019 10:36pm

I didn't run into that, but I'm not surprised. I did run into a horseback rider, that could have been a problem. At that time they probably had no idea what an ebike was, and I was going downhill in gravel so was not using power and focused on the road, but today they might be less than happy to see me especially on an uphill where it is obvious. That time Wildcat was freshly chip sealed so I headed out west downhill along the creek to the freeway to avoid it. I had to go up and around by the camping area to bypass the "no bicycle" area west of the center and stay on the dirt roads inside the park. Quite a long mostly downhill route. Fairly stressful with the poor road conditions. Not my idea of a fun commute. That was with the 9C rear hubmotor, not a great climber until I added the front BMC.

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Re: Diamondback OverDrive, the RidgeRunner

Post by ferret » Sep 18 2019 3:38am

Alan B wrote:
Sep 29 2016 7:48am
I applied some grease to the back side of the brake pads, as was suggested to reduce the rear brake howling.

It did change, but it did not solve the problem.
I use Kevlar compound pads from Discobrakes (https://www.discobrakes.com/?s=0&t=0&) on all my bikes. They are silent and don't seem to have any drawbacks.

Avner.
Don't believe everything you think.

Cove GNG-Spot build thread

Astral Rune build thread

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 18 2019 9:58am

ferret wrote:
Sep 18 2019 3:38am
Alan B wrote:
Sep 29 2016 7:48am
I applied some grease to the back side of the brake pads, as was suggested to reduce the rear brake howling.

It did change, but it did not solve the problem.
I use Kevlar compound pads from Discobrakes (https://www.discobrakes.com/?s=0&t=0&) on all my bikes. They are silent and don't seem to have any drawbacks.

Avner.
I'll keep that in mind if I can't fix it some other way.

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RidgeRunner Speedhub System Design Plan

Post by Alan B » Sep 21 2019 1:31am

Have been doing a lot of research on the Rohloff Speedhub, BBSHD and PhaseRunner
Found a local place that sells and services the Speedhub, and builds wheels

Rohloff Speedhub
14 speeds evenly spaced 13.6% apart, 5.26:1 total range
Twist grip shifter 1-14, dual cable pulls both directions, indexing internal to hub
Can shift while not moving or pedaling, shifting will complete when torque drops
1500w ebike compatible, 130 nm max torque limit
Robust chain can be used, no shifting, no derailleur (will need tensioner)

Torque
For 100kg rider Rohloff requires a minimum of 2.5:1 torque reduction gearing from a 170mm crank.
With the 42T Eclipse chainring this would be 16.8 so 16 teeth or fewer is within Rohloff's recommendations.
A 100 kg rider standing on 170mm cranks produces 1700 kg-cm torque
Which is 167 nm on the crank
At 42/16 this converts to 64 nm on the rear axle
BBSHD is rated up to 160 nm on the crank
At 42/16 this converts to 61 nm at the rear axle
Total torque at IGH input is 125 nm which is less than the 130 nm Speedhub input limit

Speeds at 60 rpm
42/16T is 3.4-18.6 mph, 5.5-29.9 kph
Gear 8, 8.6 mph, 13.8 kph (quiet low)
Gear 11, 12.7 mph, 20.4 kph (1:1)

Speeds at 90 rpm
42/16T is 5.3-27.8 mph, 8.5-44.7 kph
Gear 8, 12.9 mph, 20.8 kph (quiet low)
Gear 11, 19.0 mph, 36.0 kph (1:1)

Speeds at 150? rpm
...

IGH Gears
Gears are primarily for matching rider input to speed and non-motor use
Gears 1-7 are a little noisier due to 2:1 reduction
Gear 7 is the noisiest gear
Shifting between 7,8 is a double shift internally, two sequenced shifts occur, 7-14-8
Gear 8 is quiet, lowest of upper range
Use 8-14 normally, 1-7 for steep non-motored climbs
Gear 11 is straight through 1:1

BBSHD Mid Drive
Up to 1500W
Kv 3.27 RPM/V (48V 157, 50V 163.5, 52V 170 rpm)
Ki 2.92 NM/A so 160 nm is produced from 55 amps
Up to 160 RPM at 48V no load (3500 rpm 48V, 3800 rpm 52V, 21.9:1 gearing)
Loaded RPM?
Max torque 160 nm at crank (at about 55 motor amps)
With 42/16 this is 61 nm at rear axle

PhaseRunner Controller
96A max motor current capable (scales back with temperature)
Set to 55A or less motor current to control motor heating and efficiency as well as limit torque output
35A max battery current with minimal heatsink
Set to 25A to protect battery (could go higher short term)
Cable set for BBSHD

Cycle Analyst V3
DigiAux input switch
3 speed switch?
mount for headset bolt?

High Capacity Battery
52V 25A continuous max (1250W) 34A max
17 amp hours, 14S5P 35E
3D printed mounts provide extra support?

eof

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fechter   100 GW

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Re: Diamondback OverDrive, the RidgeRunner

Post by fechter » Sep 24 2019 8:17am

I found that if I clean the pads and rotors with alcohol, they squeal badly right at first but then get pretty quiet after the first few stops. I hate squeaky brakes.

the Rohloff has a lot going for it, but pretty spendy. Keep in mind there is a reaction torque from the hub so you may need torque arms like a hub motor.

We'll have to do a ride sometime...
"One test is worth a thousand opinions"

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Alan B   100 GW

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Re: Diamondback OverDrive, the RidgeRunner

Post by Alan B » Sep 24 2019 11:28am

We should do a ride. I've only done the one trip to China Camp, clearly there's a lot more over there to explore. Lots of good stuff over in Marin as well.

The Rohloff has some type of torque arm. Definitely important. And definitely a spendy upgrade. I have very mixed feelings on this one. Of the various items on the upgrade list the PhaseRunner is probably the most interesting. But the bike works pretty well the way it is already. I need to ride it more. I just brought it back from storage yesterday, so it will be more available to use and work on. I took it on a camping trip in January and it's been in the trailer ever since.

The brakes have squealed from new. Does cleaning help with brand new brakes? The fronts are fine, it is just the rear. Tektro Dorado as I recall. They screeched before they got dust in them, and as I recall they still screech. It's been awhile since I rode it.

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