Heavy fat ebike with hub motor, safe to do jumps?

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05silgto   100 mW

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Heavy fat ebike with hub motor, safe to do jumps?

Post by 05silgto » Nov 18 2020 1:27am

So I converted a conventional fat bike to a ebike. I used a run of the mill somewhat cheap ebay conversion kit.
http://www.bikesdirect.com/products/mot ... sprung.htm
This is the bike I used, and I believe after the conversion it weighs roughly 70lb.
https://ibb.co/SKPfzky
So, based on personal experience, how hard can I push this bike? Would it probably be able to handle small to medium jumps, or would it be a good idea to just avoid them in general?

Balmorhea   1 MW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by Balmorhea » Nov 18 2020 4:13am

Jumping a bike is foolishness, but with that out of the way, if you can jump a pedal bike without wrecking it, this one should be about the same.
___________
Finish Reconstruction.

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dogman dan   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by dogman dan » Nov 18 2020 6:57am

Well, the wheel build on a typical cheap DD motor is not that great, and no suspension to help soak up the jumps. You can damage the shit out of a cheap built wheel just by letting spokes get loose.

But at least its not a geared motor. With geared motors there is some risk to the gears, or at least the shear pin inside, when you jump with the motor on. Geared motors need to be jumped with the throttle turned off.

But all that said, can you build a nice ramp, fly 4 feet in the air, and land on the flat when you personally weigh 280 pounds? Likely not without risking some bike damage, particularly broken spokes on the rear wheel.

Jumps just vary man. When I was young, I'd huck 100 foot jumps on skis. Maybe 50 foot vertically. But sure as hell not onto a flat hard landing. Landing on a very very steep slope makes a huge difference when you fall 5 stories. Makes a difference when you fall four feet too. But I see no reason little pops, or shorter drops to steep landings could not be done on that bike.

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MadRhino   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by MadRhino » Nov 18 2020 9:58am

A 4 ft flat landing drop on hard pack can damage the best hub Motor bicycle wheel build, and most cheap frames at first try.

Jumping is a world of expansive frames and experienced riders. The learning curve is very steep, expansive, and painful. With ebikes, best is to build a robust mid drive on one of the best slopestyle or DH frames. With fat tires, it is custom domain.
Make it fool-proof, and I will make a better fool.
Current bikes
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Trek Session 10 mod. Variable geometry. 70mph
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Blip01   1 µW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by Blip01 » Nov 18 2020 2:55pm

Balmorhea wrote:
Nov 18 2020 4:13am
Jumping a bike is foolishness
:lol:

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by Blip01 » Nov 18 2020 3:45pm

05silgto wrote:
Nov 18 2020 1:27am
So, based on personal experience, how hard can I push this bike? Would it probably be able to handle small to medium jumps, or would it be a good idea to just avoid them in general?
I have one of the Gravity Bullseye e-bikes from Bikes Direct. I use it for commuting, but take it out on some local trails occasionally if I'm doing some work and need to lug tools around. I've done some small jumps, but it's sooo heavy, like mentioned, I'd be very worried about the wheels. I knocked a wheel out of round going up a curb fast. :-(

Also, the battery and controller aren't exactly mounted for taking jumps. I could see the battery ripping free of the downtube rivet mounts.

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MadRhino   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by MadRhino » Nov 18 2020 8:04pm

Blip01 wrote:
Nov 18 2020 2:55pm
Balmorhea wrote:
Nov 18 2020 4:13am
Jumping a bike is foolishness
:lol:
:twisted:

Jumping a bike is the greatest fun and skill that a rider can achieve, but it is not for everyone, nor every bike. I am getting old for that kind of fun now, but I still enjoy it when the conditions are ideal. With a hub motor, big jumps are a thing of the past, but my bikes can jump 3ft safely on the flat or DH, 5 ft uphill maybe more. Uphill jumps are much lighter on wheels, but require considerable power, or speed.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

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E-HP   1 MW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by E-HP » Nov 18 2020 8:30pm

I think that fork will bottom out, even riding off a curb, with all the extra weight. 120mm isn't a lot, and you'll have to pump up the pressure to compensate.

Tommm   100 kW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by Tommm » Nov 18 2020 8:46pm

Hardtail with hub. Depends on what you land on. If soft, you're fine. Root or rocks you will bust a spoke/rim. Same with potholes.

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dogman dan   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by dogman dan » Nov 19 2020 7:03am

You can go ahead and ride off curbs all you want, for sure, unless you have 6 loose spokes.

The consensus seems to be in, don't do what you'd call a huck unless ready for some damage. Little pops should be fine provided you have no obvious weaknesses in the bike, loose spokes, poor torque arms, etc.

999zip999   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by 999zip999 » Nov 19 2020 8:35am

Only if you have a second backup bike.

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pwd   1 kW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by pwd » Nov 19 2020 8:57am

Just playing the devil's advocate here but fat tires (4.0 + inches wide) would soften the landing somewhat depending on the tire, air pressure etc...
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E-HP   1 MW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by E-HP » Nov 19 2020 11:45am

pwd wrote:
Nov 19 2020 8:57am
Just playing the devil's advocate here but fat tires (4.0 + inches wide) would soften the landing somewhat depending on the tire, air pressure etc...
I was looking at the reviews of the fork that are using non-electrified fat bikes, which seem to indicate the fork is capable, but can't take big impacts and flexes a lot, and that's without the additional mass. The performance part of the review starts around 5 minutes in.
https://www.youtube.com/watch?v=lI72pLUqsz0

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MadRhino   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by MadRhino » Nov 19 2020 3:34pm

Well, if we are going into tires, jumping does require 2 ply wire beaded tires. Most of them are in the 2.25 to 3.0 width. Some may be found in 4.0, sure not many. Then, 4.0 tires do require fork width that is making very difficult, if not impossible, to find one suitable for jumping. Fat bike jumping is very likely to require custom mods, unless it is practiced on loose snow slopes where robust and stiff components are not as important.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

999zip999   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by 999zip999 » Nov 19 2020 5:00pm

I wouldn't do it with an aluminum frame. As I've seen pedego bikes break at the bottom bracket.

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MadRhino   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by MadRhino » Nov 19 2020 6:46pm

999zip999 wrote:
Nov 19 2020 5:00pm
I wouldn't do it with an aluminum frame. As I've seen pedego bikes break at the bottom bracket.
Steel fatbike frames are even worse.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

999zip999   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by 999zip999 » Nov 21 2020 2:55pm

Oh I guess the only steel fat bikes are Walmart stuff and not colmoly.

markz   100 GW

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Re: Heavy fat ebike with hub motor, safe to do jumps?

Post by markz » Nov 21 2020 3:12pm

999zip999 wrote:
Nov 21 2020 2:55pm
Oh I guess the only steel fat bikes are Walmart stuff and not colmoly.
Not necessarily "fat" but to me its plenty fat
https://rsdbikes.com/middlechild-chromoly/

https://cad.rsdbikes.com/product/middle ... -chromoly/
https://cad.rsdbikes.com/product/rs291-chromoly/
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https://www.pinkbike.com/buysell/2889561/

https://surlybikes.com/bikes/pugsley


edit
If I had the money, I'd go with Surly, or Surface 604 but then again I don't do much jumping, nor do I care much about the materials used for the frame. I've noticed a few 604's for sale over the past year with the electrics gone, I'd chose that frame to build upon. For jumping, the best bet would be mid drive whether purchased from store or built yourself. I like the looks of the expensive store bought ebikes, Rocky Mountain, Specialized etc but I would know I wouldnt like the wattage power they give out as I'd require more power so then I'd look at the Cyclone Elite Downhill (non boxed triangle).

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