MB-1-E ... what a difference!
I worked on the MB-1-E today.
Replaced the 60 tooth hub sprocket with a 72 tooth.
Added a short chain section to make up the difference.
I also reset the controller to default settings.
The new ratio is now 12:1 (was 10:1).
Before the sprocket change I could get up to 20 mph but it took maybe 3/4 block to get up to speed and the bike was sluggish on any noticable hill.
It was getting close to getting dark when I finished up, so I thought I'd check it out on the back street where there was no traffic.
I flipped the switch to 24 volt and clipped the alligator clip (my temporary igniton key) on to the positive to fire up the controller.
I took off slowly to make sure everything was in order then goosed the throttle ...
... I almost did a wheelie (wheel never left the ground) but it really has some torque. I was up to 19 mph in 3 seconds.
I headed around the block and on a straight stretch (level roadway) I slowly went from 19 to 20 mph.
My batteries weren't fully charged, I rode about 6 miles earlier in the day. On a fresh charge I might be able to top 20.
Man, What a Difference!!
I think this bike will really take the hills now.
I didn't have a chance to try any yet but with the way it shot off the line I have little doubt.
What's amazing is that I didn't seem to loose any top end speed. This is definately what it needed.
I knew the change in ratio would make a difference but had no idea how much.
I thought you were over geared that is one reason I suggested you make one change at a time. With this lower ratio you will also get more range and you still have a good top speed. Can't wait to hear how it takes the hills. I am so happy your hard work has paid off. Now is the time to start reprogramming that fancy controller you have to get the most out of the bike. I have one more suggestion, I would set the controller settings all to a low setting the test the bike and get some times, speeds, amp and voltage readings. Then change one parameter and see how it effects the base-line readings, set that parameter back and change another. I would make large changes so I could tell what each change does. When this process is complete you should be able to tell how you want to set the controller to get the best power and speed while using the least amount of power, amps.
Keep the front wheel low,
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I'm waiting on you to make the changes. Well, I guess it is time I catch up to you. I am off work Monday and Tuesday, will have to order that 48 tooth rear sprocket to get above a 10 to 1 ratio. Then I'll decide on whether to order another gates sprocket, my 64 tooth may also have to be changed to, to, to,,,, waiting on you Dave,
I took the day off, posted a build under the collaborative handbooks, not a neat presentation, will probably add another comment or two.
My drive is 10.4 to 1. I got down on my hands and knees to get some part #s for the build post,, my gates pulley is a 68 tooth. Gates had the 64 tooth on backorder, I remember now, I asked if they had anything close and they sent me the 68 tooth. So, I think closer to 12 to 1 would be good for me, I probably won't loose speed.
Outside ambient temperature has a very dramatic effect on my motor temp. In the mornings when I ride to work in 60 to 70 degree F temps, motor is warm, could hold your hand on there for an hour and never say it was uncomfortable. Coming home when the temps are in the eighty to ninety range F, motor is to hot to touch, maybe about 5 seconds before I have to remove my hand.
What is your chain noise on your present setup. I think most would say mine is'nt bothersome, but, with my 15 tooth sprocket it was basically silent. My current drive is primary belt, 21 and a 68 tooth. Secondary is a 14 and a 45 tooth. To eliminate chain noise I was thinking to buy that 48 tooth final chain sprocket combined with a 16 tooth chain sprocket already in my arsenal. Then get a belt sprocket in the 84 tooth range. Yes, these gear ratio changes get expensive, I always buy 2 belts, that is $20, the 48 tooth sprocket will be $30 with shipping, That Gates pulley will be in the $30 to $40 range I'm sure. These changes should drastically increase the life of the chain and sprockets, reduce chain noise to zero, decrease my motor temp,, whats a hundred bucks?
Take some more pictures of the chain adjustment areas and where they terminate at what looks like the motor on the right side and where the struts attach on the jack shaft plate, both sides. Looks to me like this will need to be upgraded, at least on the chain adjustment. From the pics, from your blog post chapter 12, looks like the theaded rod is 3/16" or less. If that is what bent I think it is being caused by a left and right movement of the whole motor assembly. A gusset between the two struts made from 14 gauge steel welded to the struts below the motor would strengthen the assembly. A good time to learn how to gas weld. EMT does'nt have much strength, I would upgrade to plumbing pipe on the struts, steel schedule pipe has very good welding characteristics, is thick walled. EMT would lose strength when heated, it becomes brittle, generally you don't want to braze or weld emt because of the gasses are toxic from the galvanization. Plumbing pipe will gain strength from welding. I don't recommend brazing steel of any type unless it was made at the mill for brazing. Hot rolled steel has a surface crust that brazing does'nt penetrate and contains impurities that weaken the bond. Brazing is a surface bond, if done on steel that is very clean it can approach the strength of a weld. In theory only, brazing is stronger than welding. Gas welding steel is much more forgiving and fairly easy to learn. I mig weld just about everything, but, can't cut steel with a mig setup. Gas gives you a lot of flexibility, cuts, is portable, solders, brazes, bronze welds and steel welds.
I understand why, no, how that adjustment bolt bent now. It is hard to believe the torque from the motor bent a 3/16 grade 8 bolt! I would still like some closups of the adjustment. My Peltzer style jackshaft is being made on the side by a friend of mine who works at a machine shop. I think I will make another bike like yours that is more on the assist side, smaller motor with a small nimh pack. I have an aluminum frame mongoose rigid tail that is very light just begging for a little motor.
One of the main reasons I abandoned the Raliegh, there are three reasons, was the difficulty of chain adjustment. Second reason was lack of a good front suspension. Third was the bike was very tall and I just felt a little uncomfortable at speed. The mongoose is a shorter frame similar to yours and came with a front suspension.
I've thought about bottom bracket drive, currently, not to apealling to me, motor would have to be very small, driving the front chainring and freewheeling have to be worked out. If i had a metal lathe I would just fabricate my own bottom bracket, use a couple of sprag clutches, throw the bottom bracket bearings on the bike away, put in sealed roller bearings, put that gates pulley on the left side attached to a sprag and the bikes chainring attached to a sprag on the right side, really very easy to do, "just hav'nt bought that lathe yet". Should buy a lathe, but I just would'nt use it enough to justify the space it would use up, shops pretty crowded.
Sprag clutch is basically a one way bearing or freewheel if you will.