Aluminium frames, what are the risks?

[cwah]

Hello guys,

I've just seen this terrible video about frame that split in 2 because of the speed:

http://www.youtube.com/watch?v=WGAeZWKkijk&feature=player_embedded

Do you guys have an aluminium frame?

From what speed we can have frame failure? Is there a risk at 30 mph?

 

[neptronix]

That's a carbon fiber frame, buddy...
Doing something like 60-100mph down a rocky mountain with no suspension.
Dumbass of the century maneuver there.

I've got two Trek aluminum frames that see regular road use, doing 30-40mph on em.. no suspension.. no probs..
Some of the highest power builds are on aluminum frames.

An aluminum frame is just less tolerant of extreme forces, it will bend a little, then snap if pushed far too hard. Steel will bend quite a bit before snapping... that's main difference.

If built right, you will never have probs. Check out what MTBR has to say about a particular bike before buying it.. always

 

[cwah]

So at 30 mph, it wouldn't be dangerous for any of these 3 bikes?

Dahon Jetstream

http://www.bikefold.com/dahon_jetstream_p8_bicycle.htm

Mezzo D9

http://www.foldingbikes.biz/html/mezzo_d9.html

Pacific If Reach

http://www.pacific-cycles.com/product3.asp?cat1=1&cat2=4&pid=2a

 

[neptronix]

The last one doesn't look like a folding frame but it is made by pacific cycles, who generally makes the cheap walmart/target/kmart stuff.. with awful, shrimpy welds..

I would not call those bikes particularly tough, then again i have never seen a tough folding bike, ever.

Trek aluminum frame, takes over 100ft-lbs to the rear dropouts on bursts of acceleration, has been hitting potholes and other nasty crap at 30-40mph for a year now, no suspension, 230lb rider.. no probs..

Just one example of a well built aluminum frame.

Like i said, look at MTBR for their reviews on a bike before buying. They abuse mountain bikes pretty hard and will often find faults with them, saving you misery and $ later on..

This is part of what lead me to stick with my Treks..

http://www.mtbr.com/cat/older-categories-bikes/2003-hardtail/trek/4300/prd_361549_1510crx.aspx

BTW i am not saying 'go get a Trek'.. just putting out one of the examples of a bombproof alu. frame that i know of..
There are many others.

 

[cwah]

Pacific if reach actually have a very cleaver folding style:

I could easily carry it on the train or even in the grocery store when needed. That's why I have interest in this bike.

I don't want to buy a full size bike. I already have one and it's way too big/cumbersome. I'm looking for a small folding bike I can carry on the tube/bus/store with me.

That's why it's so difficult to choose. These 3 folding bikes, even if they are not specially strong, won't have any problem at 30 mph I suppose?

 

[neptronix]

The only folding bike i've heard good things about is the downtube stuff, from MWKeefer..

http://www.downtube.com/

I would cross pacific bike off my list of choices whether it was steel, aluminum, or unobtanium.. you can count on their bikes to be poorly constructed for our use, anything else is an exception.

 

[cwah]

But this bike doesn't seem to be poorly constructed. In their website it even cost $2000 and the online reviews seem good.

I have very bad bike knowledge, but how is it poorly constructed?

 

[neptronix]

But this bike doesn't seem to be poorly constructed. In their website it even cost $2000 and the online reviews seem good.

I have very bad bike knowledge, but how is it poorly constructed?

Well like i said, most pacific bicycle products aren't constructed well and have scary welds, but there are exceptions.

I don't know what country you live in, but if you live in the USA, go check out some wal-marts, targets, and k-marts.. you will see these pacific bicycle products ( they will be made under various brands ) i'm talking about and have a deeper understanding of what i'm saying

And look at the downtube bikes, they are cheaper and MWKeefer is a fan.. find out who else is running folding bikes on here.. go off experience, unless you really want to be the beta tester

 

[LI-ghtcycle]

But this bike doesn't seem to be poorly constructed. In their website it even cost $2000 and the online reviews seem good.

I have very bad bike knowledge, but how is it poorly constructed?

The frame is just the main component to compare, most (not all) pacific bicycles have low-end cheap components like brakes, derailleurs, wheels/hubs, etc.

Once you buy one, and replace all the cheap stuff you will end up paying more than a similarly priced quality bike.

I generally like to buy gently used bicycles, and I have found that most major name brand bikes with decent shimmano components will get the job done best, however, there are frames, and then there are frames.

I had a Nishiki aluminum frame that broke when my nephew was getting on and off of the trailer bike I had attached to it's seat post.

Fortunately it only broke above the top tube where the seat-post clam rests, and I was able to get it welded, however, I also have a Tidal Force frame that is bullet proof that I wouldn't hesitate to put the same trailer bike onto.

I am a bigger fan of steel than aluminum because like Nep says, one will break when the other still bends.

Not only that, when aluminum breaks, it's much more serious because generally speaking to get the strength of a similar steel frame, they need to make it more hard, which can make it better than steel in stiffness, especially in extreme conditions, like Hard-Tail down-hill riding (Specialized makes EXTREMELY tough aluminum frame, steel generally will flex too much) however, when it does brake, it's not gradual, it's RIGHT NOW and you're on your butt wondering what happened! :lol:

Steel will generally bend and flex and give you some warning before it completely fails, and isn't as brittle, however, it does rust.

Any frame made just about anywhere will put up with a typical rear wheel hub motor's torque at legal power limits, so unless you are going for more than 1500 Watts, and or plan to ride WOT all the time, or carry heavy cargo, I wouldn't sweat an aluminum frame.

That being said, a new Walmart Pacific for $100 VS a used Trek/Specialized/Giant (insert premium quality bike maker, these are just ones I have personal experience with) for about the same $$$ is always going to be a better buy, and as long as it's a beefy looking well-used and proven frame (and I agree, look it up on MTBR.com, they have a lot on even older stuff!) you should be fine. 8)

 

[dogman dan]

Even the crappiest bikes I ever rode could do 30 with no particular problem. Stopping from 30, well a few had trouble with that of course.

The flip side of the coin, a few of the ebikes I experimented with, ones carrying the battery on a poor rear rack, could be quite at challenge at 15 mph.

But generally, the popularity of a hardtail mtb for an ebike is not a random thing. Stout frames with a lot of lateral stiffness make the best ebikes. The worse your battery or cargo carrying is, the more important a stiff frame gets. Possibly the best for stiff is the classic beach cruiser, because of the two extra frame braces.

 

[cwah]

I know steel frames are the best. Steel frame on MTB are even better.

But my point is that I'm not going to buy a MTB or steel frames. I can't find any MTB useful for my need (train/tube/stores) so I'm going to stick on a light folding bike. (cause I'll carry it).

The downtube is nice but it's still an aluminium frame, and I live in UK so importing it here cost almost the price of the bike. So jetstream for full suspended is a good alternative.

I'm planning to have a Bafang at 36V500W. I'll probably average 1000W and peak at 2500W because other member did it on their geared motor. Can I ride safely with any of these bike?

 

[TonyReynolds]

These guys are in the Seattle area and specialize in folders:

http://www.electricvehiclesnw.com/

They seem to have no problem with lower-power setups, which sounds like what you're looking for. You can cruise their site for ideas. We purchased my wife's iZip Rapido from these guys and they're legit. I hadn't built up my first eBike at the time. Had I known more, we would have electrified her existing bike...

 

[cwah]

Hello TonyRenolds, I've just seen the site and I think the 3 folders presented are more appropriate for my use. I'm just wondering if they're strong enough at 30mph :lol:

 

[dogman dan]

I wouldn't worry about one actually breaking. You'll need a torque arm on the dropouts of course, but that goes for everybody anyway. The only issue would be trying to load one shitty. Fairly obvious that the center triangle is not going to be there to mount the battery. So just pick one that looks like it might be stronger, less likely to get the frame flexing a lot from side to side. Make sure the rack you use to carry the battery is nice and stiff, so you don't get the tail wagging the dog so much. Don't try to carry 20 pounds of battery, keep it light, below ten pounds if possible.

Wheel size is not the issue, so don't feel like you must use large wheels. Bad pavement might affect a small wheel more, but not that much provided the tires have some size.

If you can test ride some, do so, then pick the one that feels stiffest. 30 mph is not that big a deal really. Most any bike is expected to reach 30 going down a hill. But sustained riding at 30 mph does wear on things. Ride 25mph or less most of the time and you'll be fine on nearly any bike, however crappy. You just learn to adjust to the frame movement, and know it will flex some if you pedal hard, or when you corner.

 

[cwah]

Thanks Dogman.

I just purchased the pacific If Reach at 550 GBP (850 USD):

I hope it worth it

 

[TonyReynolds]

I just looked at a video demonstrating unfolding and folding of the iF Reach. I'm gonna go out on a limb and say that looking at the way it unfolds,/folds, the weight is on the rear wheel all the time. You're gonna want a rear motor so you're not trying to balance the weight of motor on the front wheel as you try to unfold the bike. If you're commuting with this thing on public transit, you *might* look at a small set of LiPo in a backpack with a coiled cable to the bike when you're riding. I ride with an electrical harness on my BMW GS (for heated clothing, and altough it's easy to forget you're "hooked-up" the first time or two, you get used to it. That would help to keep the weight of the bike/motor lower for transport.

 

[sk8norcal]

Well like i said, most pacific bicycle products aren't constructed well and have scary welds, but there are exceptions.

I believe these are two different company,

(owns schwinn, mongoose, iron horse)
http://en.wikipedia.org/wiki/Pacific_Cycle

(they focus on folding bikes, and make the Birdy by R&M)
http://en.wikipedia.org/wiki/Pacific_Cycles
http://www.pacific-cycles.com/
http://www.pacific-cycles.com/company.asp?catid=2&id=2
and it sounds like you got it way below retail....

here's an electric IF
http://www.pacific-cycles.com/product3.asp?cat1=31&cat2=32&pid=27

 

[Toango]

Thanks Dogman.

I just purchased the pacific If Reach at 550 GBP (850 USD):

I hope it worth it

Wow that is a good price! Is it new or used? In usa nyce wheels has it for $1500 new.

And btw neptronix in their video review , peter explaines pacific and pacific cycles are different companies so im sure this is a high quality bike and not like a cheap walmart quality

 

[cwah]

Thanks tonyreynold, I'm planning to put a rear motor on it. Initially I wanted to use a bafang 36V500W, but now it seems that bmsbattery are on holidays until the 29th... I'm thinking about the mac motor now. But it seems that it's noisier and not that stealthy in black... Not sure what to decide :lol:

Toango, I get it new from ebay but the guys told me he got it from a raffle. Not sure if it's a scam yet, I know it very soon...

 

[999zip999]

Go for it, what motor where and batteries ?

 

[cwah]

Have 2 choices:
- Wait until the 29th to order from BMSBattery a bafang 36V500W on the rear wheel.
- go for a geared mac motor 500W on the rear. Problem is that black may not be as stealthy and it's also noisier than the bafang...

For the batteries, it would be either 15s or 20s lipo. (55.5V8AH or 74V8AH). Either on the rear rack or on a backpack.

 

[Toango]

Thanks tonyreynold, I'm planning to put a rear motor on it. Initially I wanted to use a bafang 36V500W, but now it seems that bmsbattery are on holidays until the 29th... I'm thinking about the mac motor now. But it seems that it's noisier and not that stealthy in black... Not sure what to decide :lol:

Toango, I get it new from ebay but the guys told me he got it from a raffle. Not sure if it's a scam yet, I know it very soon...

Fun problem. This is going to be a sweet conversion. I agree black would not look right on this bike. The bafang has nice shiny polish and will match the other components.

Lets hope its a real deal.

Also just found a thread related to pacific cycles factory. They seem to be a very innovative company and a remember reading a talented designer designed the reach. Good inside pics
http://www.canadiancyclist.com/dailynews.php?id=23256

From this thread

http://www.bikeforums.net/showthread.php/792981-A-Rare-look-inside-some-of-Taiwans-leading-manufactures-(Giant-Kenda-Pacific..)

 

[cwah]

Yeah, it seems to be a nice company, doing nice bike. Not sure it's very solid though.

So yeah you're right, better wait for the bafang. Any idea how I can get it quicker?

 

[999zip999]

55.v sounds right for a light bike. What battery setup, details ? Either color would look good. It's not the motor it's the controller and battery that's hard to hide.

 

[TonyReynolds]

Yeah, it seems to be a nice company, doing nice bike. Not sure it's very solid though.

So yeah you're right, better wait for the bafang. Any idea how I can get it quicker?

Where are you? If in North America, an Ezee geared motor from Justin at ebikes.ca would be a good choice.

BTW, I have a rear, geared MAC (in black) and do not find it noisy at all.

One thread recently mentioned a non-black MAC from cell_man. Please email him before deciding against the MAC. It's a great motor, but seriously, an Ezee on your new folder might be more than enough...

Tony