Ebike Conversions Breaking Forks

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EarlB   1 mW

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Ebike Conversions Breaking Forks

Post by EarlB » May 24 2021 4:50pm

What are people doing with their bikes when hubs rotate out?

izy   10 mW

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Re: Ebike Conversions Breaking Forks

Post by izy » May 24 2021 5:09pm

getting a new frame unless its front fork

and then installing torque arms like they are meant to

EarlB   1 mW

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Re: Ebike Conversions Breaking Forks

Post by EarlB » May 24 2021 6:12pm

I meant: What are they doing when the forks fail? Is is natural attrition from gradual accumulated stress, or more often some incident of highly over stressed forks. I have the torque arm dynamics well thought out. I even have a really good plan for keeping axel nuts from gradually working loose, because of reverse and regenerative breaking.

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motomech   1.21 GW

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Re: Ebike Conversions Breaking Forks

Post by motomech » May 24 2021 8:09pm

What are they doing when the forks fail?
They buy new ones and pay more attention installing them.
Is is natural attrition from gradual accumulated stress, or more often some incident of highly over stressed forks.
What exactly is bending enough to weaken over time?
If installed correctly and kept within reasonable power levels, a frt. drive system will last as long as a rear mount, so please don't yell fire in the theater when it's not burning.
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Chalo   100 GW

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Re: Ebike Conversions Breaking Forks

Post by Chalo » May 24 2021 8:48pm

There is no way, physically speaking, to apply as much stress to a bike fork with a motor as you can with a front brake.

The fork tips are another matter. Use proper tight fitting closed eye torque arms, or clamping torque arms, and don't worry about it.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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neptronix   100 GW

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Re: Ebike Conversions Breaking Forks

Post by neptronix » May 24 2021 9:06pm

Shame that you didn't get the memo from the vendor that you needed them.

A front fork without torque arms can't hold much more than a few hundred watts for long.
You need torque arms on the rear too when getting into higher power levels.

Bicycles were not designed with this level of power in mind and reinforcing dropouts with torque plates/arms is necessary in most situations.
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markz   100 GW

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Re: Ebike Conversions Breaking Forks

Post by markz » May 24 2021 9:16pm

At a minimum you need one torque arms, better to have 2 otherwise it doesn't take much to spin the axle, about 40nm.

https://youtu.be/c96n0Ma2rLY?t=1138

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Re: Ebike Conversions Breaking Forks

Post by EarlB » May 24 2021 10:35pm

When you say two torque arms, do you mean one on each side, or two on each side. Logic tells me you mean one on each side. Fear suggests two on each side. It bothers me that Leaf is selling me a hub kit and not mentioning the need for torque arms. I am really fortunate to have wandered into this site.

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Re: Ebike Conversions Breaking Forks

Post by markz » May 24 2021 11:01pm

Its basic information and they do not have time to lay out simple, basic info to every customer if you do not ask a question related to it.
They are not mind readers.

EarlB wrote:
May 24 2021 10:35pm
When you say two torque arms, do you mean one on each side, or two on each side. Logic tells me you mean one on each side. Fear suggests two on each side. It bothers me that Leaf is selling me a hub kit and not mentioning the need for torque arms. I am really fortunate to have wandered into this site.

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Chalo   100 GW

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Re: Ebike Conversions Breaking Forks

Post by Chalo » May 25 2021 2:11am

markz wrote:
May 24 2021 11:01pm
[The need for torque arms is] basic information and they do not have time to lay out simple, basic info to every customer if you do not ask a question related to it.
Plus there's an opportunity to sell another motor to anyone who decides they don't need a torque arm.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 25 2021 9:41pm

Chalo wrote:
May 25 2021 2:11am
markz wrote:
May 24 2021 11:01pm
[The need for torque arms is] basic information and they do not have time to lay out simple, basic info to every customer if you do not ask a question related to it.
Plus there's an opportunity to sell another motor to anyone who decides they don't need a torque arm.
If they live.

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 9:11am

markz wrote:
May 24 2021 11:01pm
Its basic information and they do not have time to lay out simple, basic info to every customer if you do not ask a question related to it.
They are not mind readers.

EarlB wrote:
May 24 2021 10:35pm
When you say two torque arms, do you mean one on each side, or two on each side. Logic tells me you mean one on each side. Fear suggests two on each side. It bothers me that Leaf is selling me a hub kit and not mentioning the need for torque arms. I am really fortunate to have wandered into this site.
For you and me maybe... Maybe not so much for the newb taking it on faith that the vendor is looking after them when they buy a kit.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 9:59am

TDB wrote:
May 27 2021 9:11am
markz wrote:
May 24 2021 11:01pm
Its basic information and they do not have time to lay out simple, basic info to every customer if you do not ask a question related to it.
They are not mind readers.

EarlB wrote:
May 24 2021 10:35pm
When you say two torque arms, do you mean one on each side, or two on each side. Logic tells me you mean one on each side. Fear suggests two on each side. It bothers me that Leaf is selling me a hub kit and not mentioning the need for torque arms. I am really fortunate to have wandered into this site.
For you and me maybe... Maybe not so much for the newb taking it on faith that the vendor is looking after them when they buy a kit.
I'm still willing to add any newb tips received to this thread, and perhaps eventually can be converted to a newb FAQ. Right now I just edit the main/first post as I see the newb questions answered:
viewtopic.php?f=3&t=111571&p=1653655#p1653227

TDB   100 W

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 6:07pm

Despite best intentions it is also a big assumption that a newb is going to find and spend many hours absorbing information on this site or any like it..

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 7:40pm

TDB wrote:
May 27 2021 6:07pm
Despite best intentions it is also a big assumption that a newb is going to find and spend many hours absorbing information on this site or any like it..
Ya, but for the mods, it might be nice for them to be able to point to where newbs can get the basic info rather than re-explaining things each time.
For myself, I know I'm not good at hand holding or coddling (raised daughters, and I'm sure they'd agree :shock: ); engineering/science/fact based responses are less personal, while newbies tend to be more comfortable with someone with a better bedside manner. FAQs can be fact based and provide information, leaving the touchy feely stuff aside. :thumb:
Last edited by E-HP on May 28 2021 1:41am, edited 1 time in total.

TDB   100 W

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 9:30pm

Vendors could also get it together and sell kits with all of the required parts or at least put them on the highly recommended list of extras to buy.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 10:07pm

TDB wrote:
May 27 2021 9:30pm
Vendors could also get it together and sell kits with all of the required parts or at least put them on the highly recommended list of extras to buy.
In an alternate universe maybe.

Grin is the only vendor that has all the parts, manuals, information, tools and videos, etc., all together in one place, as long as you are going the hub motor route. Nobody else comes close. Even with all of that, a lot of newbs don't want to do all of that reading or even taking the time to watch the informative videos. Too much information, maybe. Plus, Grin only carries quality stuff, and most people are looking for some kind of unrealistically cheap deal, even though in the end, you get what you pay for.

TDB   100 W

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 10:26pm

Not in the US crazy product liability universe?

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 10:31pm

TDB wrote:
May 27 2021 10:26pm
Not in the US crazy product liability universe?
If you buy from a US vendor, the liability insurance is baked into the price. And very few people want to pay for that premium.

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 10:44pm

That doesn't make them any less responsible.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 11:25pm

TDB wrote:
May 27 2021 10:44pm
That doesn't make them any less responsible.
So advise newbies to wait for something that doesn't exist today? I guess that would work, actually maybe pretty well. Plenty of time to read and learn between now and then. And lithium battery costs are dropping fast due to all of the utility scale stuff, so even the most costly part of the kit may go down by then too. Ebike Utopia.

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Re: Ebike Conversions Breaking Forks

Post by TDB » May 27 2021 11:33pm

Slippery one aren't you.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 27 2021 11:46pm

TDB wrote:
May 27 2021 11:33pm
Slippery one aren't you.
I do better with facts and reality, but I can appreciate and understand the vision or desire for ideals.

markz   100 GW

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Re: Ebike Conversions Breaking Forks

Post by markz » May 28 2021 1:04am

There is a learning curve, and a mechanical skill level that is pretty minimal along with tools is minimal and thats why people buy complete ebikes from their local bicycle store, or cheap out on ebay/amazon/alibaba/aliexpress.

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E-HP   100 MW

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Re: Ebike Conversions Breaking Forks

Post by E-HP » May 28 2021 1:26am

markz wrote:
May 28 2021 1:04am
There is a learning curve, and a mechanical skill level that is pretty minimal along with tools is minimal and thats why people buy complete ebikes from their local bicycle store, or cheap out on ebay/amazon/alibaba/aliexpress.
Some people are OK with taking a longer route, and others want to get to the destination, even if they really don't know where they want to go. The first ebike should be the first ebike, not the last. The cost of the first ebike is the tuition. Building it and owning it is the education. By the time you build the second one, you'll know your destination, and know what you'll need to get there.

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