40mph safety

safety at 40mph

just read some post on this subject over in a different post

im new here (so my opinion dosent count for much) but have quite a bit of experience with bikes

i would "guess" most modern freeride / downhill bikes are designed with components that can cope with stresses
of regular 30-40mph speeds - but - on harsh terrain

what were talking in most cases is the same speeds on pretty flat smooth ground - not really demanding for such a bike

jumping off a mild 4ft drop on a freeride bike will probably be as stressful as dropping off a kerb with the same bike loaded up with
electric bike bits but these bikes are designed for that stress all day everyday for a good few years

as long as the frame can take the stress of the extra weight (which is the bit its not designed for)
and as long as you gradually ease in to driving faster so you understand the capability's of your machine
then its is exactly as safe / unsafe as a moped (30 - 80cc)

is a 40mph ebike safe? no
but is a gas scooter or moped - ill let you answer

i think its very important that components are chosen for the speed you are doing - for 40mph you need a tough downhill / freeride frame think welded 4130 cromoly or monocoque alloy you need 3inch tires and high quality disc brakes

someone in the other thread mentioned the high weight of moped components - the reason behind this is because 1) the bike is heavy anyway therefore there is little point in making light weight parts 2) parts need replacing - on a moped people don't want to spend $1000 on new shocks
but i think you will find the parts on a downhill/freeride bike are stronger lighter and work better than anything on a 50cc moped - because they have to be!

now if your converting a standard mtb rigid or a road frame (not a jump frame) frame then i think 30mph is max and you really need front disc and everything needs to be good
components - its not that they cant handle the speed but its the stresses on all the parts from the weight

for a supermarket full suspension or a hi-ten steel bike i think 20 - 25 is max as the parts are all poor and it will just fall to bits

Yeah.. that sums it up pretty well..

40 mph on a bicycle depends on your location.. on busy city streets .. no go. On open roads with few stops etc... maaaabe..

I've gone that fast on my Norco ( mid grade.. downhill.. better than a wally-world cheapie, but not quite freeride... 1200 $ new in it's day, paid 1000 ) ...

And let me tell ya... it's FAST... woooo.. you lean and turn oposite of the way you want to go like on a motorcycle.. it's weird.

Cars don't expect a bicycle to go that fast, specially if you are not pedaling.. so biker beware.. but it can be done..

search " Lowell " on this forum !

Here with the 4 season and fast temperature/weather condition changes, our Quebec road suffer alot from the previous winter!

A great exemple of what montreal's people got this years:
http://espace.canoe.ca/canoe/video/flv/37816.swf

that's VERY DANGEROUS FOR BIKE!!!

I NEED TO UPGRADE TO FULL SUSPENSIONS!!!

Doc

Whoa, that's awful! That looks dangerous to a non-motorized bike .

aljsk8 said:

for 40mph you need a tough downhill / freeride frame

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(Whoa, I just found out you could quote part of a post by highlighting it!)

I'm thinking a BMX would be good, too, save for the lack of suspension. Those things are built to take a real pounding.

Doctorbass said:

Here with the 4 season and fast temperature/weather condition changes, our Quebec road suffer alot from the previous winter!

A great exemple of what montreal's people got this years:
http://espace.canoe.ca/canoe/video/flv/37816.swf

that's VERY DANGEROUS FOR BIKE!!!

I NEED TO UPGRADE TO FULL SUSPENSIONS!!!

Doc

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Tabarouette.... tappe ca a 40 !!! wooo .

Roads are not THAT bad around here.. thank god.

Doctorbass said:

Here with the 4 season and fast temperature/weather condition changes, our Quebec road suffer alot from the previous winter!

A great exemple of what montreal's people got this years:
http://espace.canoe.ca/canoe/video/flv/37816.swf

that's VERY DANGEROUS FOR BIKE!!!

I NEED TO UPGRADE TO FULL SUSPENSIONS!!!

Doc

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That's very dangerous for a motorcycle. Doesn't Quebec have a transportation budget?

CGameProgrammer said:

Doctorbass said:

Here with the 4 season and fast temperature/weather condition changes, our Quebec road suffer alot from the previous winter!

A great exemple of what montreal's people got this years:
http://espace.canoe.ca/canoe/video/flv/37816.swf

that's VERY DANGEROUS FOR BIKE!!!

I NEED TO UPGRADE TO FULL SUSPENSIONS!!!

Doc

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That's very dangerous for a motorcycle. Doesn't Quebec have a transportation budget?

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Over the lasts years our gouvernement never putted enough money tfor the road's maintenance...
Now our generation need to pay for that... :x

With this winter that seems to prolong in Quebec, we will need to be carefull on the road!!.. or to start mani brakes and suspension business.. there will be alot of money to make with that :|

Doc

Ypedal, Mets_en ca tappe en tabar......!! surtout que j'ai pas de suspension en ce moment en arrière! avec le plus gros des moteur hub qui existe pour vlo, je peut te dire que mon 5305 avec ses quelques 26 lbs donnent du fil à retorder à mon pneu arrière!! et mes rayons!!!

Fo que je m'achette un vélo avec full suspension cet été ca presse!... mais j'a pas grand argent pour le moment a mettre avec ça... ca passe plus dans le labo de batterie!! :lol:

Mais Wallmart en ont qui pour 300$ semblent asses solide et bien construit! et avec une belle place pour les batterie avec un bon centre de gravitée !!! check ça: http://www.walmart.com/catalog/product.do?product_id=4698935



Doc

Meh, in normal conditions potholes are just an annoyance, they're easy to avoid when you go slow and when you go fast it gets easier to jump them. They've been an issue for me while drafting buses on roads I'm not familiar with, being able to see only a few meters ahead at that speed means you have to think fast and never lose your concentration, that's quickly exhausting.

IMO the real safety issue at that speed is that cars seem to expect bicycles to go 15-25km/h. They misjudge me rather badly when I'm hauling ass at 40, for example. Altho, I really do like kicking dents in cars that cut me off and such... lulz

BTW last I heard Quebec accounts for 1/3rd of Canada's auto suspension repairs. They say our roads age very fast because of this thing called winter. Speaking of which, the streets are pretty much clear.

Mathurin said:

Meh, in normal conditions potholes are just an annoyance, they're easy to avoid when you go slow and when you go fast it gets easier to jump them. They've been an issue for me while drafting buses on roads I'm not familiar with, being able to see only a few meters ahead at that speed means you have to think fast and never lose your concentration, that's quickly exhausting.

IMO the real safety issue at that speed is that cars seem to expect bicycles to go 15-25km/h. They misjudge me rather badly when I'm hauling ass at 40, for example. Altho, I really do like kicking dents in cars that cut me off and such... lulz

BTW last I heard Quebec accounts for 1/3rd of Canada's auto suspension repairs. They say our roads age very fast because of this thing called winter. Speaking of which, the streets are pretty much clear.

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I remember snow like that when i was a kid growing up in noyan Que back in the 50's. looks like the cycle is coming back ..lol so much for global warming

now if your converting a standard mtb rigid or a road frame (not a jump frame) frame then i think 30mph is max and you really need front disc and everything needs to be good
components - its not that they cant handle the speed but its the stresses on all the parts from the weight

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Now I disagree here. How much weight are you placing on that bike from the electrical components? And how much weight are you adding from the rider? 50lbs compared to 200lbs. Sure, it adds considerable weight, and it hurts handling like no other, but that extra weight won't make a bike disintegrate. It's the sustained vibration at those speeds that kills most things.

for a supermarket full suspension or a hi-ten steel bike i think 20 - 25 is max as the parts are all poor and it will just fall to bits

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Well that depends on a lot of things. I bet a $75 big box full suspension bike would survive 40mph. Of course, it would be an awful pogo stick at that speed, with the poor shocks. When you get to the >$150 range, the supermarket bikes can really be a good value for ebikers who want a full suspension for comfort on the road. Just don't try to take those "mountain bikes" to any mountains.

IMO the real safety issue at that speed is that cars seem to expect bicycles to go 15-25km/h. They misjudge me rather badly when I'm hauling ass at 40, for example.

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Exactly. Even Lowell, at 60mph, gets idiots trying to take his lane.

..lol so much for global warming

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Global climate change... not warming.

lazarus2405 said:

Now I disagree here. How much weight are you placing on that bike from the electrical components? And how much weight are you adding from the rider? 50lbs compared to 200lbs. Sure, it adds considerable weight, and it hurts handling like no other, but that extra weight won't make a bike disintegrate. It's the sustained vibration at those speeds that kills most things.

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Heh, a clydesdale like that is gonna punish bikes no matter what, but generally the rider's weight won't do much since it becomes negative over potholes and such while it doesn't take much before a bike gets impossibly heavy and take a beating on every bump. It'll certainly fare better to have a 90kg rider with a 15kg bike then a 75kg rider and a 40kg bike.

Not much safety at over 20. People in here smashing into cars, dogs, breaking bones. Hope everyone has a good attorney. Who's next to wreck at high speed?

From my experience with hopping up mopeds and running 2 stroke RD350s: :wink:

Always know your road - take it carefully the first pass, checking for wet leaves, sand, branches, potholes etc.

High speed: Sunny day, no cross winds, good roads, low or no traffic, intersections few and far between.

Look far ahead and expect the worse: If there is a dog, cow, kid etc on the curb/sidewalk assume it will jump out in front of you at the last minute .

Don't go fast over a hill (with our power I assume we won't).

If you are going to miss the turnoff - then miss it - don't get indecisive and end up 1/2 way between (did it with my MR2).

Supress the urge to race mopeds, bikers, etc in a congested area.

Don't ride sick, drunk, tired or on meds.

DK

The only 2 times I have really busted my butt was trying to make a turnoff on a hopped up moped and hit a sand patch, other was racing a Honda moped and hit a series of waves in the pavement that started my front end to shimmy (and lost control).
My brother hit buzzards lighting off a dead dog. He was doing 70 around a sweeper curve.

i would think most bicycles can handle 40mph. i do 30mph all the time and i have a really shlte Chinese ebike frame. i know my frame is shlte because if i try and ride no hands the front starts to oscillate heavily and you have to grab the bars again to stop it getting worse!

I would really place the safety on bicycles at 50 MPH because once you get over that speed, wheel balance and how tru the wheel is starts to really stand out on a very small wheel (compared to a thickness and strength of a motorcycle wheel for example) and hitting objects at that speed due to the low mass of your bike tends to make it harder to control than a bigger, heavy machine in which a bump doesn't jump you around as much.

Watch the video, http://endless-sphere.com/forums/viewtopic.php?f=6&t=568

Fast forward the movie using the cursor to 20:55 where you'll see me get up to 47 MPH (76 KPH) in traffic.

During the ride, it looks rough on the camera (not the best camera mount), but the ride was smooth as silk the entire way, no problems at all. I had to come to an emergency stop because the car in front of me slammed on their brakes, but my canti-lever brakes did the job just fine. I've always been able to stop my heavy e-bike on a dime with canti-lever brakes, much better than any car. I've avoided many fender benders that way in which the cars in front me couldn't stop in a short enough distance, but my e-bike still stops on a dime no matter how fast I'm going.

Off road, yeah it would destroy itself on the first tree stump, but mine is designed more for on-road city riding than off-road rock hopping. I think a heavy duty mountain bike frame is really unnecessary if you have good roads and some shocks already on your e-bike. Good brakes help too. It also depends on your skill riding a bicycle as well since that plays a good part into how well you mesh with traffic on your e-bike.

LOL, dude your brakes sound like crap,

Impressive speed, BTW.

You apparently have better cantilevers than I do. Even if I rough up the rim and brake pads some, they won't stop near as well as even my single front disc. :?

nice stopping power on that bike! impressive. i have front disc, front rim and rear plug breaks but i still feel i need more stopping power sometimes.

Link said:

LOL, dude your brakes sound like crap,

Impressive speed, BTW.

You apparently have better cantilevers than I do. Even if I rough up the rim and brake pads some, they won't stop near as well as even my single front disc. :?

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Yeah, a little alignment problem with them, but loud brakes (the front is the loud one) gets a drivers attention. I have to replace them about every 1,000 miles, but they are cheap at Wal-mart for about $3, so it's not a big deal for me to really wear them down.

monster said:

nice stopping power on that bike! impressive. i have front disc, front rim and rear plug breaks but i still feel i need more stopping power sometimes.

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Well you would certainly out-stop me then, but I like to take the route of "if I can stop well before a car can, I'm doing ok". Not that I wouldn't mind the double stopping power of some disc, but well gotta go with what you have.

I like the legacy of my e-bike since it's so old now, LOL.

Woo! Party!

D-Man said:

Then its official then! Everyone: Knightmb says Its fine to go 50 mph on your ebikes! It is totally 100% ok. Thats it then, I'm going to get the fastest hubmotor available and run high voltage and go 50 mph right down the street in the middle of traffic. It will be totally safe. Hell, I won't even wear a helmet. Whats the point? My ebike will be totally safe at 50 and if I crash into a stationary object, there won't be much left anyway!!! Yeeeeeeeee Haaaaaaaa

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What the hell are you going on about? Motorcycles can "safely" handle 130+ mph because they're designed to handle it without the wheels coming off, or the frame buckling, or the brakes failing, but that doesn't mean you can't die even at just a 20 mph collision if you're wearing no gear.

This thread, in case you weren't paying attention, is regarding the mechanical safety of e-bikes. It is well known that aluminum frames cannot safely handle the torque of an X5, meaning the dropouts will likely get torn apart by the torque of the motor. And some bicycle brakes may not give the stopping power required for a bike going 40+ mph. But in general, bikes can handle the stresses they'd suffer on paved roads at 40+mph, as many of us, including knightmb, can attest.

Regarding the ability of e-bikes to go 40+mph without mechanical failure, who is a more trustworthy source: someone who has never gone over 25 mph on one, or people who have ridden extensively at 40+ mph?

you need to pay serious attention your stopping power if you are thinking of going outside the 15mph x 40kg "box."

you will need to beef up your drop-outs if you are intending to use serious torque from acceleration or plug braking. thats more about rate of change of speed than about pure speed.

as i said in the OP road safety is not really in question - any speed on a public highway is dangerous - pedal bike, scooter, motorbike, car - all very bad ideas when it comes to safety - im wondering - do posters like D-man think that 20mph on a bike is safe? if your in an accident its going to be some car that hits you - so 20mph or 40mph it makes no difference

the difference comes if you bike cannot cope with 40mph - if the brakes arnt up to the job then there is high risk

generally most bike components can handle these speeds but its time that will destroy them
bikes dont fly to bits but cheep bikes will deteriorate quicker than most - frames should be fine if there steel
and on cheep bikes they tend to be thick walled tubes

id worry about gears, wheels and aluminum frames on a budget bike - the extra stress will cause fatigue and you dont want something like a wheel to fail
mid run

so fair enough you dont need a downhill bike but if you do use one your going to be as good or better than a 50cc moped

i posted originally because i saw ridiculous comments about going fast on bikes - it actually made me wonder if these comments were from people who have ever ridden a bike or e-bike

Alex

knightmb said:

I would really place the safety on bicycles at 50 MPH because once you get over that speed, wheel balance and how tru the wheel is starts to really stand out on a very small wheel (compared to a thickness and strength of a motorcycle wheel for example) and hitting objects at that speed due to the low mass of your bike tends to make it harder to control than a bigger, heavy machine in which a bump doesn't jump you around as much.

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I'd agree with that. I've been to 50 on my touring bike, riding back from the highest pub in Ireland (sober) with a following gale. If I were to do that sort of thing on a regular basis, I would rather be riding a long wheelbase recumbent. With full suspension. And disks.

Good aerodyamics are vital at that speed. Most of us don't contribute much by pedalling at above 25 mph. My favourite downhill trick is to stop pedalling, go into an aero tuck, and sail past sweating mountainbikers.

There are several local hills on which I can reach 40 mph and feel perfectly safe. The trick is to know how much distance you need to stop, and sit up and prepare to brake whenever the length of clear road you can see ahead starts to diminish.