Converting an all aluminum bike, front hub motor

[sephiro499]

I have a trek navigator 400 I bought on craigslist a few years ago. I believe it is the 2001 model because when I bought it the guy said it was 10 years old. I want to convert the front to the clean republic hill topper kit, since it's the easiest to install. I know that using a front motor with an aluminum fork is not safe, so I wanted to switch out the fork. The problem is I don't know how to do it. My reading online indicates there are 3 different sizes of forks and also whether you want a straight fork or curved at the end.

The fork says odesa 178, I tested it with a magnet and it did not stick, so I assume it is aluminum.

I've also thought about buying an ebike but I do not think I could get something as nice as the bike I already have for 500, the cost of the kit.

 

[e-beach]

I want to convert the front to the clean republic hill topper kit, since it's the easiest to install. I know that using a front motor with an aluminum fork is not safe, so I wanted to switch out the fork.

Hey sephiro499! Welcome to ES.

Step 1 is to go to your User Control Panal / Profile / Location: and tell us where you live. At least what country. We have people from all over the world on this forum so to point you to the right direction to meet other e-bike builders or venders or other cool e-bike stuff we need to know where you live.

My first e-bike was a front hub "riged" Trek 800 with a steel front fork. I thought it would be the eaisest way to go for me. The whole thing turned out to be a big PITA. The ride was so harsh I eventually bought a mountain bike with suspension forks.

Today I run on the same 36v 800w front hub motor that I put on my mountain bike with aluminum alloy front forks. Lots of us around here have motors on our front suspension forks. What we go is ground out about 2mm of alloy on each side so the 14mm hub motor axle will center up in the fork. We also use c washers and torque arms on both sides for safety, There is no reason that you need to go with a front hub motor. IMHO it is easier to put one on the back for these reasons. No need to looks for steel forks. No need spending the time putting them on. You can save the money and apply that to a battery pack which is where 1/2 to 2/3's of you money should go anyway. The steel front forks will give you a much harsher ride then a bike with suspended front forks with a rear hub motor. If you already had a steel front fork, then yea, it might be easier, but in your situation it becomes more trouble then you think.

I would do this: Find out how big the axle is on the kit you want. Call or email Clean Republic and ask them. If it is 10mm then you can use your aluminum alloy forks with 2 c washers and 2 torque arms for safety. If they tell you the axle is 14mm then seriously consider going to a rear hub motor.

Here is a link on how I did my battery box and front forks "on the cheap". http://endless-sphere.com/forums/viewtopic.php?f=3&t=39690

Let us know how it is going.

 

[dogman dan]

Best bet to replace it with a steel rigid fork will be the surly suspension corrected fork.

But you can safely run a lower power motor in an alloy fork. The real problem is often that it simply won't fit.

I have two threads that explain in detail how it's done and what you need to buy, if you find that the motor has enough space between the tubes to fit without rubbing. It's c washers and torque arms, properly fitted. I've got about 8000 miles of use of this method with 1200w of power, and never broke a dropout yet. Just don't try it at 3000w.

Another option is to find a specific type of steel suspension fork. It would have the dropouts welded to the inner side of the tube, rather than the center. This give you the clearance the motor typicaly needs.

 

[Ykick]

Fairly large triangle Trek and you wanna front hub motor? Those frames make for excellent triangle battery bags and a rear motor balances everything very nicely while being more stealthy.

I've had (and still do) front hub eBikes and they're okay but the best ride feel is acheived with a rear motor and frame mounted batteries. Much easier to pop the front wheel up over curbs and just feels more natural overall.

I know it seems like geeky work to sort out the derailer and fit a rear motor but how much work's swapping fork gonna require?

 

[d8veh]

For a 250w motor, you don't need to change your forks. Most 250w ready-made Chinese bikes with front motors have aluminium forks and don't even use torque arms. I've had two of them and did thousands of miles without problems. I think on your bike I'd fit a torque arm just to be sure. The important thing is not to have a washer or nut over-lapping the dimple (lawyers lips), which means using an eccentric washer or filing the drop-out deeper to re-centralise the axle.

 

[dogman dan]

Yep, the only reall issue is the question of whether the motor fits into the space. If it does, go for it with a good torque arm.

I now have more rear hub bikes than front hubs. But I still kinda like the fronties if the riding doesn't require curb hops or dirt. I like that pulling you along feeling. Great traction in corners with the power on.

 

[motomech]

Yeah, that bike would be a good canidate for a frt. mount, slow wind cute(Q100) and a bottle battery from BMS Battery, Elifebike or Greenbikekit.
That would make for a nice, clean, low cost assist up to 20 mph.

 

[sephiro499]

I want to convert the front to the clean republic hill topper kit, since it's the easiest to install. I know that using a front motor with an aluminum fork is not safe, so I wanted to switch out the fork.

My first e-bike was a front hub "riged" Trek 800 with a steel front fork. I thought it would be the eaisest way to go for me. The whole thing turned out to be a big PITA. The ride was so harsh I eventually bought a mountain bike with suspension forks.

Thanks for the warm welcome and to all that have responded.

I am open to a rear wheel install. The front sounds more complicated now that you guys have went over some of the details. I live in an apartment and have limited tools. If I go with a rear kit, do I take the gear sprocket thing off the rear wheel and put it on the new wheel? In other words, do I still have access to my gears, or do I not need them? My trips will be less than 5 miles one way, to give you an idea of how far I will be going. Where I live there is no shoulder, and no bike lane. The speed limit on the road out front is 40mph, and that is just a suggestions. In the wabash area, the speed limit is largely irrelevant, and I value my life. I might be willing to ride on the road but only during the late evening or very early morning. I will stick to the sidewalk where it is safe.

 

[dogman dan]

A good rear kit will be easy to install. Idealy, it would come with a 7 speed freewheel installed. If not, a bike shop can take one off your bike, and it will fit on the motor. Sometimes the cheaper kits require a bit of fiddling with extra washers to get the rim centered, but nothing too hard to do.

The only really difficult thing about a rear install is usually getting disk brakes to line up. If you have rim brakes, no problem.

You'd still want a torque arm, but arms designed for the front usually don't fit, or require some modifications to fit well. Grin cylclery sells a torque arm designed for the rear.

Just go for a rear kit, I'd say. If you do have any problems with installing it, we are here to help you get er done. You should not need much more tools than a crescent wrench, and some allen wrenches for adjusting the brakes, installing the throttle, etc.

 

[d8veh]

Everything is simple in principle, but often complicated in detail. A 250w rear motor normally goes straight in. Most rear motors have the thread for a free-wheel up to seven speeds, some can go up to 8 speeds. If your present bike has a cassette gear set that goes on a spline, you have to buy a free-wheel set. The cheaper free-wheel sets only go down to 14 teeth on the top gear, which means it's difficult to pedal past 15 mph. You can get 11T sets from Ebikes.ca, which restore your normal pedal speed to what it was before. Depending on how many gears you've already got, you might lose one or two. You can often keep your changers and rear derailleur, which will probably still work, but obviously one or two positions will be redundant. There are increasingly more motors that take a cassette. The 350w and 500w Bafang CST is a proven example, but you can find loads of 250w ones on Aliexpress.com, but I've never seen a report on one, although they're probably OK.

A quick-release front wheel usually has a 9mm axle, in which case your drop-outs will need to be filed/ground out a bit to accept a front motor. You can check by using anything that's 10mm wide or diameter to see whether it fits in, and if not, by how much. Occasionally, you have to widen the rear ones too- for a rear motor. You can check those as well.

For a 250w motor, it makes little difference whether you go front or rear. There's advantages and disadvantages of both, which make them equal. If you go up from 250w, the advantages swing to the rear. Filing the drop-outs isn't a big deal. It just takes a bit of time and you need to be fairly precise. It can be done in about 2 minutes with a Dremmel and the right milling bit. You can buy a torque arm with your kit, and they just bolt on.
http://www.bmsbattery.com/450-a-pair-of-ebike-torque-arm.html

As you have cable brakes, you should get these brake sensors, so that you don't have to change your brake levers:
http://www.bmsbattery.com/459-hwbs-hidden-wire-brake-sensor.html

If you decide on a bottle battery, avoid those smaller than 10aH because they're not very powerful.

 

[Drunkskunk]

Welcome to the forum.

The Trek 400 used a 1-1/8" headset, A very common size. Most suspension forks are going to be that size. However, the Trek 400 had a rather long stem, longer than common, so finding a used fork that would fit the length would be tricky. You will likely need to buy new, and that can be expensive.

That bike is Ideal for a rear motor, center battery setup. That will keep the bike nicely balanced rather stealthy.

The rear gear set is 8 cogs, most Ebike rear motors can take 7. An 8 cogged freewheel can be fitted, but that can be tricky. It may be something you can do with hand tools in an apartment, but it may get more involved. If you use a 7 cogged rear, you'll likely have to replace the shifter to get the spacing right. Though you may never shift again. After 6 Ebikes, I built my last bike with no shifters at all. I've found I never used them.

A good kit from one of my favorite vendors would be the MXUS 500w motor http://em3ev.com/store/index.php?route=product/product&path=36&product_id=54

Regardless of what motor you get or which end you stick it in, use torque arms.

 

[sephiro499]

Welcome to the forum.

The Trek 400 used a 1-1/8" headset, A very common size. Most suspension forks are going to be that size. However, the Trek 400 had a rather long stem, longer than common, so finding a used fork that would fit the length would be tricky. You will likely need to buy new, and that can be expensive.

That bike is Ideal for a rear motor, center battery setup. That will keep the bike nicely balanced rather stealthy.

The rear gear set is 8 cogs, most Ebike rear motors can take 7. An 8 cogged freewheel can be fitted, but that can be tricky. It may be something you can do with hand tools in an apartment, but it may get more involved. If you use a 7 cogged rear, you'll likely have to replace the shifter to get the spacing right. Though you may never shift again. After 6 Ebikes, I built my last bike with no shifters at all. I've found I never used them.

A good kit from one of my favorite vendors would be the MXUS 500w motor http://em3ev.com/store/index.php?route=product/product&path=36&product_id=54

Regardless of what motor you get or which end you stick it in, use torque arms.

Thank you for the information. Yes I did count the number of cogs and there were 8 on the back rim. This is starting to get a little too complicated. I don't even know how to replace a cog, and then like you were saying if I went to a 7 I would have to replace the entire shifting system. I still want to use the bike as a regular bike and have gears to shift when I don't need or want the electric assistance.

I thought about buying the skyline, but I've read online it's cheaply made, especially the wheels. Something about the spokes not being done right? I looked at the prodeco ebikes on amazon, but they have proprietary tubes and tires. They also said if the rear gets a flat it's very difficult to replace. I don't want anything I can't work on myself with off the shelf parts.

 

[toaroa]

The two front drive ebikes I currently maintain...

WIFE's 300w bafang, aluminium suspension forks, c washers, no arms, no problems, even after 3530km and many overnight/off road trips

MINE 350w+ Mac, alu frame upon which I put a surly/steel/nonsuspension fork, no arms, no trouble after 4125km and even more multiday offroad trips. It is a bit front heavy, esp since I shifted battery/controller to handlebar so toddler's bike seat could go on back but... No troubles.

My conclusion: mean /maxwatts have a lot to do with what you can get away with, but I reckon they both have to be high before torque arms are worthy of consideration.... A good torque wrench, on the other hand, now that's a sensible purchase

 

[sephiro499]

Ok so If I'm going to do this I think the rear is the best option. Mostly since I don't then need to buy a very expensive front fork. As luck would have it, or not, on the way home today my rear tire started to lose air from the sidewall. It looks like I need to replace the tire and tube, so I took off the rear wheel.

The sprocket says SRAM 5.0 and on the bottom side says Lock-----> 40Nm.

So, do I need to replace my derailer and my handlebar shifters, if I get a freewheel with less cogs? If the hub motor is 'geared' do that mean my bike does not need gears? I will need to install the cogs onto the new rim with the built in motor, right?

 

[Ykick]

Interal geared hub motor has nothing to do with the bicycle freewheel sprocket other than being attached to the hub motor. Internal geared or direct drive (DD) the freewheel threads on either one the same way.

Don't worry too much about the bicycle gearing (Several of us don't use shifters) lock in tallest gear and let the motor help with start up. That's what it's there for, right? Shifters can be worked out too but requires a little time and effort to sort out the bicycle parts you already have and the freewheel you end up with on the hub motor.

 

[mark5]

sephiro499, in case you're uncertain about how easy it could be to convert your bike it might be helpful to watch the Hyena Electric Bikes kit installation tutorial below. In 13 minutes he shows installing a kit using minimal tools--an adjustable wrench and a hex key. He shows installing the freewheel, just screws it on the hub motor. Yours could potentially go as easy too.

[youtube]WwIp3GC5F_c[/youtube]

 

[sephiro499]

sephiro499, in case you're uncertain about how easy it could be to convert your bike it might be helpful to watch the Hyena Electric Bikes kit installation tutorial below. In 13 minutes he shows installing a kit using minimal tools--an adjustable wrench and a hex key. He shows installing the freewheel, just screws it on the hub motor. Yours could potentially go as easy too.

[youtube]WwIp3GC5F_c[/youtube]

Yeah after reading more it doesn't look too bad. I know for the hub motor it will either take the threaded flywheel or the cassette type. The reason I ask about the gears is because there are times when I may not want the electric power. I assume the battery will be the heaviest part of the kit, so if I'm just going outside for exercise I would disconnect the battery and lose the extra weight. Now changing to a 6 sprocket from an 8 sprocket I assume I will also need a new derauler and shifters, since on amazon it lists the deraulier with the number of supported gears. If I'm going to do this conversion I would like to do everything right the first time. This will also give me a great education and confidence that I can handle any replacement or maintenance in the future.

 

[mark5]

I only have a 7 speed freewheel on mine so don't know about going from 8 to 6 speeds. But would this help:

8-Speed Casette to 7-Speed Freewheel
http://endless-sphere.com/forums/viewtopic.php?f=3&t=30083

Gears and shifters recommendations?
http://endless-sphere.com/forums/viewtopic.php?f=3&t=36150
In this thread I think BATFINK's Sheldon Brown speeds link and dogman and corkscrew's posts are most applicable if you would use a 7 speed instead.

 

[dogman dan]

If your bike has an 8 speed cassette now, then it will be possible to just swap in a 7 speed screw on freewheel that you will put on the motor.

The chain will still fit, it's not as narrow as chain for 9 speed.

But your shifter indexing won't be perfect in all 7 gears. Typically we end up not using the biggest cogs on a rear gear cluster anymore once you have the motor. You just don't need them to get moving from a stop, so you leave it in the higher gears. So just just adjust your cable on the derailur so it indexes good on the higher gears, and if you do need to ride the low gear someday, just make a quick adjustment of the cable length with the barrel nut on the shifter.

In practice though, you'll find just using the front shifter will work, leaving the rear on the highest 3-4 gears that index well. Pedaling, you need ratios that are very close to each other. With the motor, you only need every other ratio on the rear. Once rolling 10 mph, high gear is fine.

As for riding the bike without the battery, you can do that, particularly with the freewheeling planetary gear motors. But if you really like riding your current bike normaly, here is where I really recomend that you get a second bike for the motor. I love my Ebikes big time!!!, But the garage still contains one road bike, one hybrid bike, and two mountain bikes I have no intention of ruining with a motor.

Bear in mind, you can get all the exercise you want with the motor running. Just set the throttle for a given speed, then pedal up 2 mph more speed. You'll be amazed how much work you can still do. The only thing is you'll just get there quicker. The ideal exercise is to pedal just enough to get the heart going good, but not get out of breath. Ebikes are perfect for this. One hour of constant light exercise that is fun beats 15 min of gym misery every time.

 

[motomech]

sephiro499 WROTE-QUOTE<<<< Yeah after reading more it doesn't look too bad. I know for the hub motor it will either take the threaded flywheel or the cassette type. The reason I ask about the gears is because there are times when I may not want the electric power. I assume the battery will be the heaviest part of the kit, so if I'm just going outside for exercise I would disconnect the battery and lose the extra weight. Now changing to a 6 sprocket from an 8 sprocket I assume I will also need a new derauler and shifters, since on amazon it lists the deraulier with the number of supported gears. If I'm going to do this conversion I would like to do everything right the first time. This will also give me a great education and confidence that I can handle any replacement or maintenance in the future.>>>>END OF QUOTE


This, as with so many first timers, has gotten way more complicated than it needs be and I guess we are partly to blame for throwing lot's of irrelevent suggestions out there.
You stated that you are going to need to ride on the sidewalk and want to pedal, ok, that means low-powered geared mini-motor, PERIOD.
That Hill-Topper kit has that, and the couple of guys here on ES said it was an OK kit, but you would want to get one of the lithium battery options.
It mounts on the front with a few hand tools, the bicycle drive-line stays intact and it will be fine for what you want to do.
It's kind of slow at 15 mph, but a reviewer here said he could pedal up to 19 mph, so if your bike has the gearing and you have the leg strength, you could do the same.
It comes with a really low power controller, probably around 10 to 12 amps, so if you wanted to add things like a more powerful controller, a real throttle, torque arms, etc. later, you could do so.
Or you could save yourself some time and just get an Ananda Q100 kit like I susgested earlier, which comes with a real throttle, has better battery options and will be more powerful. The "Cute" kit is well thought of, not just by me, but by D8veh. And if there is anybody you should listen to, it's him. He is the low-power God/Guru when it comes to assist conversions, having built/helped build more than a dozen beautiful examples. If you want to do some research, search out his builds here and at Pedalecs UK.
Look at the three sites I susggested and go though the checkout to see what shipping will be, if you are smart about it, you will end up with a nicer conversion for less money than the Hill Topper kit.
Although I would just use a frt. kit, the Q100 is the easiest rear mount hub motor to mount available. There is room for you to use an 8-speed free wheel. Even though you wouldn't have to change out any of the shifting stuff, if you use a DNP free wheel, it probably won't shift as smoothly as it does now. Since you won't be going faster than 20 mph, I think you could have the option of using one of the nicer Shimano free wheels.

The reason I ask about the gears is because there are times when I may not want the electric power. I assume the battery will be the heaviest part of the kit, so if I'm just going outside for exercise I would disconnect the battery and lose the extra weight.

A lot of posters here who haven't yet experienced an Ebike think this, but the reality is, once you are electrified, you will use it all the time. You still pedal as hard as you want, you just do it now to go further and faster.

If I were you, I wouldn't send any more time to keep mulling this over and second guessing things, just focus on which mini-motor kit you want to go with and get it ordered.

Here are a couple of nice Q100 conversions by Grinz145 and zukster;

http://endless-sphere.com/forums/viewtopic.php?f=3&t=32364&hilit=zukster

zukster's is more what you have in mind. Note that he uses a 9-speed free wheel w/ a Q100 Rear motor.

 

[e-beach]

@ sephiro499,

So what is your budget anyway?

 

[dogman dan]

Cool, I was unaware that such a thing as an 8 speed screw on freewheel existed. Thought 7 was the max for screw on. All my 8 speed bikes have the cassete.

 

[motomech]

Yeah, all three, Sunrace, Shimano and DNP offer 8-speed free wheel units.
The Shimano even has a 13T sm. cog, which, with a 44 to 48T chainring might be a pretty good set-up for "sidewalk" speeds. Looks like it's kinda rare though. I only see it on the UK amazon site.
I swapped a DNP 9-speed on a Cute rear mounted and even though the bike was new, I never could get it adjusted to shift as nice as the cassette. NBD, just sometimes I need to double click to move one gear, or sometimes it will jump a tooth with one click.
I think it may have to do with the nickel plating, with makes the sprocket a little wide for the 9-speed chain.

Just to clarify why I feel strongly the OP needs a mini-motor is that he lives in Md., as I do. Md. has recently instituted some of the strickist Ebike laws in the country and if one is going to ride on the sidewalk, it's a good idea to keep the speed down and the motor small. Just like anywhere else, the cops are kinda busy and usually won't give a second look, but best to play it on the safe side, especially if the route is a regular commute.

 

[sephiro499]

Let me try and answer everyone's questions. My budget is around 500 dollars. I will use the kit to help me pedal when I'm either having a bad day or too tired. I ride my bike around the neighborhood, to the library, dr's office, grocery, dollar store, wendys, all trips are within 3 miles. I have once ridden to the mall which is 5 miles, all on the sidewalk. If it's late enough I sometimes ride on the street with my helmet and lights on. Since I don't work I only use my bike to get to places when walking would take too long.

I'm looking at this kit

http://www.bmsbattery.com/ebike-kits/426-250w350w-q-85100sx-motor-e-bike-kit.html#idTab2

This is the kit recommended by motomech and from the site he also recommended. After reading about the complicated and expensive front fork situation, plus safety, I would like to go with a rear kit as long as I don't have to change all my shifters etc. Can I just take the 8 sprocket freewheel off my current rim, and use it with the q100? While I'm at it, should I just get a new freewheel since the one I have is 10 years old? Sometimes it does it stuck in half gear so to speak but I figured that was a function of the derauiler. I believe moto said I could but I wanted to make sure. Then all I need is a battery and a case? How about the 12V17Ah LiFePO4 ABS Shell Battery Pack and the 'little frog' case?

About my tires, I currently have the knobby mountainbike tires, and I thought smooth road type tires would be more efficient. I need a rear tube and tire and I mine as well do the front as well so it matches. Several searches indicate there isn't much difference between innertubes. My bike right now seems to lose air within a week or so. I don't know if this is normal. Since I'm already taking everything apart I want to get a good quality innertube and tires to minimize flats and having to always pump up the tires.

 

[motomech]

$500, and you need tires and tubes?
I guess your budget should have been the first question asked and we could have saved a lot of discussion.
You really don't have any options and can't even afford a free wheel to use a rear kit(no, your cassette is different and won't work).
You need to use the frt. 201 front Q100 kit to save money, your forks will be fine with this kit @36V. Get the torque arms.
pick the least expensive 36V battery that has at least 8Ah. hat's smaller than we prefer, but you don't go far. Remember, if it's a rack battery, you will need a rack.
Go to all three sites I mentioned and price the shipping by going though the checkout.
You might just be able to afford to do this, it's the shipping costs that will determin that.