steel ebike frames

stevenast

Well-Known Member
Chromoly steel makes sense in so many ways for ebike frames. Who is using it?

One reason so many manufacturers of bikes use aluminum frames is consumer demand that is based on an incorrect assumption a few pounds lighter makes a RL difference.

I know a lot of people on here have made a financial commitment to aluminum and will probably try to justify why it is better, or as good, but the question here is which ebike makers are using steel frames (in other words bikes that won't develop micro stress fractures and fail like aluminum).

The only real advantage aluminum has to buyers is that is won't rust, but the brittleness and danger of catastrophic failure is higher with aluminum.

With the extra power and weight of an electric motor & battery, ebikes should all be manufactured from high quality steel. Does anyone know who is doing that?

Thanks!
 
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Brambor

Well-Known Member
not sure who does that but there are quite a few BionX conversions of Surly bikes and AFAIK Surly uses steel on their bikes.
 

George S.

Well-Known Member
They put large torque arms on the Prodeco X3. Plus you can beef up the forks.

Question: If a bike has disc brakes, the stopping action puts massive circular stresses on the forks. If a bike is designed for discs, what does that mean in terms of motor stresses? Anything?
 

George S.

Well-Known Member
The Storm is steel. Some bikes direct bikes (no motor) use chromoly forks.
2014 Izip E3 Zuma is listed as Chromoly.
 
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Hong

Active Member
Steel is a great material to make a cheaper ebike. Some customers may not notice the added weight, but aluminum is the industry standard for strong and light bicycles, electric or otherwise. You can't just compare the base material strengths, it's about optimizing your frame designs for the material you're using.
 

stevenast

Well-Known Member
Steel is a great material to make a cheaper ebike. Some customers may not notice the added weight, but aluminum is the industry standard for strong and light bicycles, electric or otherwise. You can't just compare the base material strengths, it's about optimizing your frame designs for the material you're using.

I think you are referring to high-tensile steel like used in the $150 bikes at Wally-world.
Aluminum is not really all that strong and it is quite brittle, but it is cheap and lightweight. So if bike makers use enough of it they can get by.
Chromoly (alloy) steel is stronger and more resilient, absolutely better for electric bike construction.

One more thought: "industry standard" just means "what sells for the highest profit". I just wanted to make sure you did not confuse that with "quality" or "good".
 
Aluminum bikes are pretty cheap by now... The Sondors eBike is a steel frame. Not chrome moly.

For a mountain bike would definitely go for a aluminum frame and suspension fork.. eBike or not.

For a road bike there are so many choices.. I have 3 Reynolds Chrome moly frames with Campy fork ends.. Those frames will outlive me, and at the same time provide a compliant ride without any suspension or CF forks.. Weight difference with aluminum is quite small.
 

stevenast

Well-Known Member
Yes there is an appreciation for steel frame bikes and those go for relatively high prices.

http://www.rivbike.com

Only reason (quality) steel bikes cost more is economies of scale, because aluminum is the flavor of the month. Steel itself is inexpensive.

Re: mountain bikes, that would absolutely be where I would want steel, to take the beating (with suspension fork!). To me, if any bike uses aluminum, road bikes seem more suited to its light weight and stiffness.

Ebikes: absolutely ill suited due to brittle, cracking aluminum.
Ebikes, with their weight and power should be made with quality steel frames.
 

Reddy Kilowatt

Well-Known Member
I think one reason aluminum is so widely used is that it lends itself to hydro-forming. That process allows varying tube diameter and even shape. For example the down tube of my Optibike Pioneer Allroad varies continuously over it's length. By the bottom bracket it's round; at the stem end it has a rounded square cross section. I don't think that can be done with steel, but I'm not sure if it's really needed. Those Rivendells are oh so beautiful. If they ever make an eBike I think I'm gonna' have to rob a bank so I can buy one.
Allen
 

Hong

Active Member
I think you are referring to high-tensile steel like used in the $150 bikes at Wally-world.
Aluminum is not really all that strong and it is quite brittle, but it is cheap and lightweight. So if bike makers use enough of it they can get by.
Chromoly (alloy) steel is stronger and more resilient, absolutely better for electric bike construction.

One more thought: "industry standard" just means "what sells for the highest profit". I just wanted to make sure you did not confuse that with "quality" or "good".

I think you should read up on material properties before making blanket statements like, "Aluminum is not really all that strong and it is quite brittle." If this were true, they probably shouldn't make airplanes out of the stuff.

I've owned custom made steel bikes, high-end carbon, and everything in between. Aluminum is a great material to build a bike frame, and it's not just "what sells for the highest profit". It's way cheaper to make a steel frame, and somehow you think that's the *best* material.

Quality isn't based on the material used. It's based on the design, engineering and craftsmanship that goes into the bike.
 

stevenast

Well-Known Member
Blanket statements? Your reply is full of them... contradictory as well!
You think materials are not part of the quality equation, yet you owned "high end carbon"
You think airplanes having aluminum content erases the weaknesses of that metal.
Your response is nothing but "spin"...talking around, but never addressing the point:

Chromoly steel is stronger and more resilient than aluminum. (your argument also pretends there's no difference between high tensile steel and chromoly steel).

But aluminum is much easier to shape into sensuous curves is also cheap.

Therefore the ebike (all bikes actually) marketplace demands aluminum, and manufacturers push it on the market, even though stronger, safer ebikes would be made from chromoly steel.

I'm not selling either metal. What are you selling?
 
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