Which hardtail to convert to rear hub ebike?

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Laissez   1 W

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Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 03 2021 10:59am

Which one you think would be the best option for ebike conversion with rear hub motor(500W MXUS XF15)? After riding for a while with my hybrid with no suspension I'm going to switch it to something with 100mm front suspension. I'm mainly driving on roads (which can be in a bad shape during winter when it's snowing), bumpy gravel roads and some forest trails. I'm mainly using tyres with really high puncture protection so they are a pretty hard ride with no suspension and going +18mph/30km/h

Currently I'm thinking about to get one of these used for max 300€/$364: Cube AIM/Analog models, trek marlin 5, White xc 290, Ghost kato. Any experiences with converting these or do you have anything else to recommend?

https://www.cube.eu/en/2020/bikes/mount ... nred-2020/ Image
https://www.cube.eu/en/2020/bikes/mount ... llow-2020/ Image
Trek: https://www.trekbikes.com/international ... 5/p/23134/ Image
White: https://whitebikes.com/xc-290-comp-20/b/2432/ Image
Ghost: https://www.ghost-bikes.com/en/bikes/ha ... al-29-2021 Image

My MXUS XF15 motor: Image
battery: Image
Last edited by Laissez on Jan 03 2021 12:42pm, edited 1 time in total.

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E-HP   1 MW

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Re: Which hardtail to convert to rear hub ebike?

Post by E-HP » Jan 03 2021 11:40am

They all look like they'd work fine. The Trek appears to have the least battery space, but it depends on the size frame you're looking at. The Ghost has rack mounts, so for me, I'd want those, and looks like most of the cabling is internal keeping thing neat.

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Re: Which hardtail to convert to rear hub ebike?

Post by 999zip999 » Jan 03 2021 12:05pm

Are the brakes and shifters separate for the new ebike brake handles or could use the add on brake cutoff switch. Plus look at space around rear derailleur is there enough space for the big axle nut to fit next to the derailleur some derailers or so close there's not enough space to put a nut in the axle on the frame. Do you have enough space for the battery you wish to use. Figure it all out make a cardboard box besides the battery and see where you're going to put it. Figure it all out before you make the purchase.

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 03 2021 12:31pm

E-HP wrote:
Jan 03 2021 11:40am
They all look like they'd work fine. The Trek appears to have the least battery space, but it depends on the size frame you're looking at. The Ghost has rack mounts, so for me, I'd want those, and looks like most of the cabling is internal keeping thing neat.
Yeah good notice my current bike is like this, I have 24Ah 48V Hailong case battery:
Image
999zip999 wrote:
Jan 03 2021 12:05pm
Are the brakes and shifters separate for the new ebike brake handles or could use the add on brake cutoff switch. Plus look at space around rear derailleur is there enough space for the big axle nut to fit next to the derailleur some derailers or so close there's not enough space to put a nut in the axle on the frame. Do you have enough space for the battery you wish to use. Figure it all out make a cardboard box besides the battery and see where you're going to put it. Figure it all out before you make the purchase.
I have the magnet sensor cutoff system which works great with hydraulic brakes. That cardboard trick sounds good, I'll do it and go to test in the bike shops.

Image

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Re: Which hardtail to convert to rear hub ebike?

Post by 999zip999 » Jan 03 2021 4:08pm

Get a big nut and see if you have room for the axle and nut as I have a hardtale hanging in the garage because of that.

Laissez   1 W

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 03 2021 4:40pm

999zip999 wrote:
Jan 03 2021 4:08pm
Get a big nut and see if you have room for the axle and nut as I have a hardtale hanging in the garage because of that.
Yeah I'll have spare nuts from the current build which I can use to look this up. At least I found one build out of the models I looked and it seems even DD rear hub motor fits well so I shouldn't have problems fitting geared one.:

Cube Aim rear hub dd conversion:
https://www.youtube.com/watch?v=xmHrjuadXNw
Same for trek marlin 5/6 with dd rear hub and battery also fits fine:
https://www.youtube.com/watch?v=YtF_16RA2Jo
https://www.youtube.com/watch?v=lT77TkNkikg

It's a shame that I bought 28'' hub wheel kit and not 27.5'' one. Limits my options a bit on MTB's.

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Re: Which hardtail to convert to rear hub ebike?

Post by E-HP » Jan 03 2021 5:26pm

Looks like either frame could benefit from a little light filing of the dropouts to get the axle to fit 1-2mm deeper.

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Re: Which hardtail to convert to rear hub ebike?

Post by markz » Jan 03 2021 6:44pm

It appears to have less battery space because the picture is probably of a small bicycle frame. The main thing I look at is the relationship between the top bar at the seat post and the top of the wheel but with the new bicycles who knows if thats really something to look at when trying to figure out sizes of bicycles. Another thing to look at is the space between bars at the headset, I know with older bikes there can be quite the distance with 20" frames. But again, the new geometries of new bicycles they can end up doing some funky "new age" stuff like various honing tube methods and welding techniques which the eng's/architects are trying to please the customers eyes. I like older bicycles for a few reasons myself, they are cheap, they are less expensive and they cost less :lol:
E-HP wrote:
Jan 03 2021 11:40am
They all look like they'd work fine. The Trek appears to have the least battery space, but it depends on the size frame you're looking at. The Ghost has rack mounts, so for me, I'd want those, and looks like most of the cabling is internal keeping thing neat.

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 03 2021 7:29pm

E-HP wrote:
Jan 03 2021 5:26pm
Looks like either frame could benefit from a little light filing of the dropouts to get the axle to fit 1-2mm deeper.
Yep, had to do some filing on my current bike also.
markz wrote:
Jan 03 2021 6:44pm
It appears to have less battery space because the picture is probably of a small bicycle frame. The main thing I look at is the relationship between the top bar at the seat post and the top of the wheel but with the new bicycles who knows if thats really something to look at when trying to figure out sizes of bicycles. Another thing to look at is the space between bars at the headset, I know with older bikes there can be quite the distance with 20" frames. But again, the new geometries of new bicycles they can end up doing some funky "new age" stuff like various honing tube methods and welding techniques which the eng's/architects are trying to please the customers eyes. I like older bicycles for a few reasons myself, they are cheap, they are less expensive and they cost less :lol:
I have perfect cardboard for measuring the battery. Going to get used bike anyways, my limit is that I need fairly new mtb because I bought the motor with 700c wheel so I need 29'' mtb. I'm 174cm/5 feet 8½ inches frame size m or l, before 2010 it seems most mtb's were 26'' and after that 27.5'' and 29'' for the tall guys and now in the recent years 29'' for the smaller guys also.

28''/700c wheel + my 50-622 winter tire is about 72cm/28,4 inches in height, not sure if they fit in 27.5'' mtb frame
Image

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Re: Which hardtail to convert to rear hub ebike?

Post by markz » Jan 04 2021 1:55am

29" wheels and hubs dont play nice together especially so with a low power hub.

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Re: Which hardtail to convert to rear hub ebike?

Post by MikeSSS » Jan 04 2021 3:50am

Hub motors need torque arms to prevent the axle from spinning in the dropouts. Dropouts must have enough open space around them for the axle nut and for the torque arms. Some frames have sort of hoods or flanges around the dropouts, I'd avoid such a frame. The GMAC rear hub motor avoids torque arm fit problems.

A rear rack is very handy, a battery can sit in a bag atop a rear rack. Rear hub motors and rack mounted heavy batteries cause problems when stopped, not so much when riding, dismounting and mounting the bike can be tricky.

Mounting the battery in the front triangle gives much better weight distribution when using a rear hub motor.

Hardtails with a rear hub motor can transmit a lot of jolt energy to the seat, that's bad for the spine. A suspension seatpost can take the edge off this jolt by spreading the upward energy over a longer time. I've ridden suspension seatposts on hardtails about 10,000 miles, even cheap and simple suspension seatposts are useful, but long travel is better than short travel.

A comfortable riding position is very nice to have, different frames and configurations can change the feel of a bike and the comfort level a lot.

Longer rear triangles give better ride and send less shock to the seat. Some cheaper factory ebikes mount the battery behind the seat tube, thus giving a longer rear triangle, the rear axle is moved farther rearward.

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 04 2021 8:36am

markz wrote:
Jan 04 2021 1:55am
29" wheels and hubs dont play nice together especially so with a low power hub.
Well I'm running 700c wheels and 50-622 tires already and it works nicely, top speed about 45km/h. My motor runs 700-900W most of the time, it's mxus xf15 with 48V battery.

It seems if I run Schwalbe marathons they could fit 27.5'' mtb frame:
https://www.youtube.com/watch?v=R1W7NgUHoH8
MikeSSS wrote:
Jan 04 2021 3:50am
Hub motors need torque arms to prevent the axle from spinning in the dropouts. Dropouts must have enough open space around them for the axle nut and for the torque arms. Some frames have sort of hoods or flanges around the dropouts, I'd avoid such a frame. The GMAC rear hub motor avoids torque arm fit problems.

A rear rack is very handy, a battery can sit in a bag atop a rear rack. Rear hub motors and rack mounted heavy batteries cause problems when stopped, not so much when riding, dismounting and mounting the bike can be tricky.

Mounting the battery in the front triangle gives much better weight distribution when using a rear hub motor.

Hardtails with a rear hub motor can transmit a lot of jolt energy to the seat, that's bad for the spine. A suspension seatpost can take the edge off this jolt by spreading the upward energy over a longer time. I've ridden suspension seatposts on hardtails about 10,000 miles, even cheap and simple suspension seatposts are useful, but long travel is better than short travel.

A comfortable riding position is very nice to have, different frames and configurations can change the feel of a bike and the comfort level a lot.

Longer rear triangles give better ride and send less shock to the seat. Some cheaper factory ebikes mount the battery behind the seat tube, thus giving a longer rear triangle, the rear axle is moved farther rearward.
I have 2x torque arms installed already and I have battery in the triangle, I don't think it's good idea to keep battery in the back because hub motor is already there. I think about the suspension seatpost also when I get the hardtail, which one do you use? My current bike is like this:
Image

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Re: Which hardtail to convert to rear hub ebike?

Post by markz » Jan 04 2021 5:24pm

For a 29/700 setup it depends on the kv or turn count of the motor. The lower the rpm/volt the better. Also the total weight, but your dealing with normal weight.

viewtopic.php?f=2&t=109219&p=1599194&hi ... l#p1599194
Problem with a hub motor in such a large rear wheel and slow (off road?) uphill riding is overheating the motor. So if you really want a hub motor you're better of with a larger/wider one then needed for the speed you're after. Search for "Fat bike hub motor" to find one.
viewtopic.php?f=30&t=66489&p=1596070&hi ... l#p1596058

Further down
DD
viewtopic.php?f=30&t=66489&p=1596070&hi ... l#p1596151
I'll continue to preach until I'm blue in the face that no direct drive hubmotor should be geared with a 29er. While the motor may be able to handle it, that can only be true until you try to climb the wrong hill...or simply the wrong day...and no matter what that choice of wheel size forces you to carry more battery that would a smaller wheel even after the greater performance you get with the motor in a smaller wheel. Instead run the smallest wheel you can live with. Even if it's only down to a 26", it's an improvement, though I regard that as still too big. Plus you get the added benefits of more battery space for the same wheelbase, and with 29ers so much more common for pedal bikes, used 26ers should be far cheaper.


So there might be a difference in the analogy between dd's and geared for larger wheel diameter.

Answer might be found in this thread, just a random post for the link but the title is good to read through. Gotta go for now.
viewtopic.php?f=3&t=105619&p=1545321&hi ... r#p1545321

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 04 2021 5:37pm

Today went to check this: https://www.trekbikes.com/fi/fi_FI/polk ... 7/p/33194/

Trek x-caliber 7 2018 model. It had too small triangle in 17.5 size to fit the battery. Otherwise it could've been amazing. Not sure if I want to install battery to downside of the downtube.

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Re: Which hardtail to convert to rear hub ebike?

Post by fatty » Jan 11 2021 4:11am

E-HP wrote:
Jan 03 2021 11:40am
The Trek appears to have the least battery space...
Laissez wrote:
Jan 04 2021 5:37pm
It had too small triangle in 17.5 size to fit the battery. Otherwise it could've been amazing. Not sure if I want to install battery to downside of the downtube.
Triangle size would not be high on my frame decision tree. Ease of mounting? Marginal. Safety/Protection? Also marginal.
Get the best bike frame and fit the battery wherever it fits.

Look for a frame with standard 135mm dropouts, modern tapered headtube and large diameter seattube, room for wide tires, light weight alloy construction, fork with modern thru-axle and hydraulic disc, etc.

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 12 2021 7:29pm

fatty wrote:
Jan 11 2021 4:11am
E-HP wrote:
Jan 03 2021 11:40am
The Trek appears to have the least battery space...
Laissez wrote:
Jan 04 2021 5:37pm
It had too small triangle in 17.5 size to fit the battery. Otherwise it could've been amazing. Not sure if I want to install battery to downside of the downtube.
Triangle size would not be high on my frame decision tree. Ease of mounting? Marginal. Safety/Protection? Also marginal.
Get the best bike frame and fit the battery wherever it fits.

Look for a frame with standard 135mm dropouts, modern tapered headtube and large diameter seattube, room for wide tires, light weight alloy construction, fork with modern thru-axle and hydraulic disc, etc.
Yep got myself new bike. Year 2014 Cube Acid for 220€/268usd, bike is really nice and the geometry is good for me:
Image

Battery fits in the triangle, not sure how to attach it though. Need to think something.

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Re: Which hardtail to convert to rear hub ebike?

Post by 999zip999 » Jan 13 2021 10:55am

Don't you hook it up at the water bottle rivets ? You can get a kit to install rivet nuts . ? Not sure of the nut thread size. I never use one but two Velcro strips would be added.

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Re: Which hardtail to convert to rear hub ebike?

Post by fatty » Jan 13 2021 1:12pm

999zip999 wrote:
Jan 13 2021 10:55am
Don't you hook it up at the water bottle rivets ? You can get a kit to install rivet nuts . ? Not sure of the nut thread size.
At that point, why not just directly blind rivet the battery mount to the frame, rather than rivnut?

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Re: Which hardtail to convert to rear hub ebike?

Post by 99t4 » Jan 13 2021 11:21pm

Laissez wrote:
Jan 12 2021 7:29pm
Battery fits in the triangle, not sure how to attach it though. Need to think something.
Can you get the slide-in mount for the battery? They are very common. Then attach the slide-in mount to the downtube via the existing water bottle bracket 5mm screws.

Here is an example (recommend you mount your battery on the top side of the downtube; more secure, better protected from water and rock impact, you have the space there).
https://www.reddit.com/r/ebikes/comment ... ack_under/

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Re: Which hardtail to convert to rear hub ebike?

Post by Laissez » Jan 14 2021 9:45am

999zip999 wrote:
Jan 13 2021 10:55am
Don't you hook it up at the water bottle rivets ? You can get a kit to install rivet nuts . ? Not sure of the nut thread size. I never use one but two Velcro strips would be added.
They are too low for the battery mount spots. I'll drill some rivnuts maybe.
99t4 wrote:
Jan 13 2021 11:21pm
Can you get the slide-in mount for the battery? They are very common. Then attach the slide-in mount to the downtube via the existing water bottle bracket 5mm screws.

Here is an example (recommend you mount your battery on the top side of the downtube; more secure, better protected from water and rock impact, you have the space there).
https://www.reddit.com/r/ebikes/comment ... ack_under/
Battery fits fine inside the triangle and my battery mount has integrated controller:
Image
Image

I was thinking about getting my Cube a mid drive kit(tsdz2 or bbs02) and seperate battery mount. Any suggestions for good mounts that takes hailong battery?

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