Anyone done a carbon fibre ebike ?

General Discussion about electric bicycles.
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superdave   10 mW

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Re: Anyone done a carbon fibre ebike ?

Post by superdave » Aug 17 2012 7:29am

Dudeofdoom wrote:I seriously love carbon fibre & Ti as a material but I'm not sure they are the greatest of things to stick between your legs.

Old fashioned steel/ali's more forgiving and forewarning....better a creak than a crack.

But an alloy space frame structure with carbon cladding wud be nice 8)

DoD
Ti is actually a far better frame material (from a failure standpoint) than heat treated Al. Ti's properties (especially when it comes to fatigue) are similar to steel but with a higher tensile strength and lower density.

Bikey   1 µW

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Re: Anyone done a carbon fibre ebike ?

Post by Bikey » Aug 17 2012 8:15am

I made an enquiry about this bike for my Mrs and at the same time discovered that this company previously sold a carbon electric mountain bike. They still have the ex-demonstrator which is soon to be sold on ebay. Its quite local to me (about 30 miles) so I may pop in there and see what its all about. Does anybody know this brand?

http://www.ebay.co.uk/itm/Kudos-Eco-Ele ... 4d03f00b3c

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t3sla   10 kW

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Re: Anyone done a carbon fibre ebike ?

Post by t3sla » Aug 17 2012 8:32am

errr you going front or rear hub?

edit: why don't you use PAS only that way lots of power and it forces you to pedal :D
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Bikey   1 µW

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Re: Anyone done a carbon fibre ebike ?

Post by Bikey » Aug 17 2012 10:18am

Do you mean one where the motor is in teh bottom bracket rather than in one of the wheel hubs?

Dudeofdoom   100 mW

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Re: Anyone done a carbon fibre ebike ?

Post by Dudeofdoom » Aug 17 2012 1:15pm

superdave wrote: Ti is actually a far better frame material (from a failure standpoint) than heat treated Al. Ti's properties (especially when it comes to fatigue) are similar to steel but with a higher tensile strength and lower density.
It probably is but ask my mate who managed to break two expensive Ti frames in a short period of time after never breaking a Al one his feelings on the subject :D

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Re: Anyone done a carbon fibre ebike ?

Post by Dudeofdoom » Aug 17 2012 1:22pm

I'm starting to sound like an advert for the company but on-one.co.uk have very reasonably priced carbon frames...

I've been watching them for a while as I'm looking for a frame for a my summer commuter..
(Phasors for the winter)

DoD

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Chalo   100 GW

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Re: Anyone done a carbon fibre ebike ?

Post by Chalo » Aug 17 2012 2:40pm

superdave wrote:Ti is actually a far better frame material (from a failure standpoint) than heat treated Al. Ti's properties (especially when it comes to fatigue) are similar to steel but with a higher tensile strength and lower density.
I think the track record for well-designed aluminum bike frames is every bit as good as for Ti frames so far. Adjusted for cost, there is no doubt which is the better material for bikes. You have to carefully cherry-pick criteria to make Ti seem superior to aluminum, but a frame costs like ten times as much.

Ti alloys can have higher tensile strength than mild steel, but not nearly as high as the better alloy steels. In terms of strength, modulus, and density it's in between steel and aluminum, with its modulus to weight ratio being a little less than the other two. Its fatigue characteristics are more like steel, and its corrosion characteristics are more like aluminum. I think it would be a fine alternative material for bicycle frames except that its high cost makes it unattractive for all but fetishistic uses. I will say this: Pure titanium would make a fine bike frame by today's standards, while pure aluminum or pure iron would not.

Compared to Ti and the more conventional metals, carbon-plastic has significant advantages and even more serious disadvantages. It's really much more similar to wood than to metals.

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Samd   1.21 GW

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Re: Anyone done a carbon fibre ebike ?

Post by Samd » Aug 17 2012 3:53pm

Here ya go just wrap it in this. The German guy is probably taking the piss and doing it too. http://carbonfibrevinylwrap.net.au/carb ... vinyl-wrap

Dead cheap on fleabay...

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Re: Anyone done a carbon fibre ebike ?

Post by SoSauty » Sep 04 2012 11:07am

I've just rode a 'Century Ride' on my dept store schwinn e-commuter. A few folks laughed and yelled 'Cheater!' but being a charity run, folks were OK with my electric. Interesting, the local bike shop manager and I traded places for around 30 miles thru the mounains. He killed me on the straights and a bit down slopes, but I regained position climbing the 5-900' slopes. Used 0.8K batt over 104miles/4600'.

Where the e-machines really shine is power assisted climbs. A mini geared to allow pedalling would be the ticket. My thinking along this line is to use a viable CF rig with Bafang rear (the grey motor would blend). 4 8Ahr 5S lipo bricks in 2Series2Parallel would yield 37V and 592Watts of energy. Perfect for the metric (62mile) rides. The 700cc wheels give just enough speed and pedalling with it would save the little nylon gears.
http://www.bikerumor.com/2012/07/31/201 ... s-weights/
There's some grey tinted lexan that would be sorta easy to heat and bend to build an aero batt box in the ah-hem triangle area or split with 2 lipos aside the chainring.
http://www.interstateplastics.com/Gray- ... -POLLE.php
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t3sla   10 kW

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Re: Anyone done a carbon fibre ebike ?

Post by t3sla » Sep 20 2012 8:36am

Endless Spirit.

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Grey beard   100 W

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Re: Anyone done a carbon fibre ebike ?

Post by Grey beard » Sep 20 2012 12:24pm

This might open an eye or two.
http://www.pinkbike.com/news/santa-cruz ... t-lab.html
I don't know much about Chinese frames, however a little about those built by Felt. The road racing frames weigh 725-825 grams with front fork, and the carbon Mtn bike, full suspension frame is about double that without front fork. They are very light, and expensive.

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Chalo   100 GW

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Re: Anyone done a carbon fibre ebike ?

Post by Chalo » Sep 20 2012 3:19pm

I'm pretty sure that 700-900g is the frontier of road bike frame weight without a fork (or anything else, in a small size, etc.) It's still amazing, until you see some of the things such frames are capable of:

http://www.pardo.net/bike/pic/fail-001/FAIL-116.html
Image

Image

This was a Trek Madone frame, a little heavier that what you're talking about, and manufactured by a bigger, more reputable company with more engineering resources. Turns out it's no match for an out-of-alignment wheel reflector.

Don't have unrealistic illusions about carbon fiber reinforced plastic. It's remarkable what can be accomplished with it, but it's not magic. If your senses tell you a frame feels like it's made out of Kleenex and wishful thinking, listen to them. They are not entirely wrong.

Chalo
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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Re: Anyone done a carbon fibre ebike ?

Post by Hyena » Sep 20 2012 7:58pm

WOW, it punched right through and out the other side!
I'm surprised the stay didn't fragment and shatter.
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winkinatcha   10 kW

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Re: Anyone done a carbon fibre ebike ?

Post by winkinatcha » Sep 20 2012 8:21pm

:shock:

Man... that would make me cry, and done by a dinky POS reflector!

Yar I'm sticking with mah metal :)

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Tex   1 µW

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Re: Anyone done a carbon fibre ebike ?

Post by Tex » Sep 21 2012 5:48pm

Lo-po but very tidy here
www.vivax-assist.com/en/produkte/vivax-und-carbon.html

Ive often wondered if you could hack a vivax to up the power...

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t3sla   10 kW

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Re: Anyone done a carbon fibre ebike ?

Post by t3sla » Sep 21 2012 10:22pm

you need kevlar reinforced/laced carbon fiber to decrease impact damage.

hmmm how about a GNC kit on a carbon bike :P
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Chalo   100 GW

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Re: Anyone done a carbon fibre ebike ?

Post by Chalo » Sep 21 2012 11:06pm

t3sla wrote:you need kevlar reinforced/laced carbon fiber to decrease impact damage.
Nope. Fiber is still fiber, and has nil for off-axis strength. Kevlar/epoxy is not tough; it'll bust just like the rest of that crap. Apply the forces oblique to the fibers (as in impact damage), and it's just epoxy.

Think of it this way: Would you prefer steel armor plate for use as armor, or a bunch of parallel steel wires stuck together with glue? That's the difference between a steel frame and a CFRP frame with regard to impact resistance. Their tensile strength might be similar, but their durability and versatility is not the same at all.

Chalo
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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winkinatcha   10 kW

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Re: Anyone done a carbon fibre ebike ?

Post by winkinatcha » Sep 22 2012 5:57am

Chalo wrote: Nope. Fiber is still fiber, and has nil for off-axis strength. Kevlar/epoxy is not tough; it'll bust just like the rest of that crap. Apply the forces oblique to the fibers (as in impact damage), and it's just epoxy.

Think of it this way: Would you prefer steel armor plate for use as armor, or a bunch of parallel steel wires stuck together with glue? .

Chalo
bad analogy
Tho yer big n stuff, I'll be betting you haven't worn much armour to make that statement... maybe you have... I HAVE and I KNOW... Also worn kevlar bullet proof vests... woven steel for chain mail woven kevlar fibre for the vests... I'll take it over heavy arsed steel plate any day...

Joe
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I have a pretty comprehensive e-bike/bicycle workshop and run an e-bike centric business.
http://frankencycle.me/

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Grey beard   100 W

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Re: Anyone done a carbon fibre ebike ?

Post by Grey beard » Sep 22 2012 9:48am

Chalo wrote:I'm pretty sure that 700-900g is the frontier of road bike frame weight without a fork (or anything else, in a small size, etc.) It's still amazing, until you see some of the things such frames are capable of:

http://www.pardo.net/bike/pic/fail-001/FAIL-116.html
Image

Image

This was a Trek Madone frame, a little heavier that what you're talking about, and manufactured by a bigger, more reputable company with more engineering resources. Turns out it's no match for an out-of-alignment wheel reflector.

Don't have unrealistic illusions about carbon fiber reinforced plastic. It's remarkable what can be accomplished with it, but it's not magic. If your senses tell you a frame feels like it's made out of Kleenex and wishful thinking, listen to them. They are not entirely wrong.

Chalo
The pictures are interesting, but reflectors aren't standard equipment on the Trek Madrone, which is their most expensive race bike, and I can't see someone buying an up to $13K bike and putting reflectors on it. IMHO, that is a staged picture.
Stated that Trek is "a bigger, more reputable company with more engineering resourses"
I know that Kristen Armstrong won the Gold @ the Olympics on a Felt, and the woman's team that medaled were riding Felts as well. We only had about 4 medals in cycling. How many did Trek win?

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Chalo   100 GW

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Re: Anyone done a carbon fibre ebike ?

Post by Chalo » Sep 22 2012 3:02pm

The CPSC requires that all new bikes be furnished with wheel reflectors. The shop doesn't have to put them on, and the buyer doesn't have to take them.

In this case, the shop did put the reflectors on, and the damage in the picture occurred on a test ride at the shop.

http://www.flickr.com/photos/caseygordon/3900900137/

Whatever Felt's credentials, they are not as large a bike manufacturer as Trek, and they don't spend as much on engineering. Remember what Lance and the USPS team were riding all those years when he was unbeatable? My point is that no amount of engineering can make a sub-1kg frame reliable for daily practical use, regardless of material. But CFRP frames have vulnerabilities that no metal frame suffers.

Technically, riders of Huffy bikes have won Olympic medals too.
Image

Chalo
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Re: Anyone done a carbon fibre ebike ?

Post by amigafan2003 » Sep 22 2012 3:46pm

Bontrager HCM road fork on 2011 TREK FX 7.5.

3500miles in one year, 900watts peak, 25mph'ish, torque arm both sides, normally loaded with change of clothes and work laptop on rear pannier rack. I weigh 92kg (103kg last summer).

Image

I have no fear over breaking it.

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