Steel frame with V brakes, or Alum frame with Disc brakes >?

[lowquality]

Motor will be a 1500w rear hub motor with a 48v20ah Samsung battery.

http://lunacycle.com/motors/conversion-kits/golden-motor-v5-magic-pie-complete-kit/ is the motor/kit

What should be more important? I can find steel framed mountain bikes with V brakes, or I can find aluminum framed Mtn bikes with Disc brakes.

I am looking for a suitable bike to install my very first electric bike motor on, The one I have is a road bike and have been told it would not be a safe bike even with torque arms (I have 2 torque arms purchased)

The problem I am seeing is that they do not make a steel framed bike with disc brakes, or not one for under $700 as my budget is $500ish and I did not ask the guy to search the real expensive bikes.

So MY question is this, as a fat guy, 280lbs, stopping power seems to be needed. But at the same time, at 280 lbs, a solid frame is also needed. Which is needed more? less than %20 of my riding will be in heavy traffic and almost 95% will be on paved roads.







Just for a 2nd opinion, I was told this bike would not be safe even with Torque arms as it has mediocre at best V brakes and aluminum frame with steel drop outs (tested with magnet) And I have basically given up on using this bike as a host bike (might put a smaller motor on it later) would you agree?

 

[d8veh]

You're lucky. Your front forks have the post mounts for a disk brake. Yoy should be able to find a wheel with a disk on Ebay, your local bicycle recycling centre, a junk yard or wherever. Then, fit a hydraulic disc brake. Any branded one will be OK. You can get good used ones from Ebay. Make sure that the hose is long enough because your handlebrs are quite high.

Nearly all the braking is done by the front, so you don't need to change the back one. I wouldn't want to ride that bike with an all up weight of nearly 350 pounds at 30 mph and those brakes. The pads will melt on the first attempt to stop.

 

[lowquality]

You think the frame is safe? Says in owners manual 270lb max load but my 400lb brother rode it . Its releigh venture 3.0 from like 09 or 10 or similair.

 

[nutnspecial]

Hi, welcome! D8ve's advice sounds good.

If you reverse the roles here, would you feel comfortable condoning a complete stranger exceeding the manufacturer's limits on their bike?
Agreed, not the best idea on that one.

As far as steel vs aluminum etc- steel dropouts would be nice, but you're not planning on crazy power, so maybe a newer economical frame with the hydro brakes would be a beneficial direction.
But if you come across a nicer older vbrake steel frame, you could always use the v brakes with regen, and upgrade the front fork to accept a big hydro.
Best!

 

[bowlofsalad]

https://en.wikipedia.org/wiki/Fatigue_limit

Other structural metals such as aluminium and copper, do not have a distinct limit and will eventually fail even from small stress amplitudes.

This doesn't necessarily mean that the frame will crack the moment you sit upon it, but what this does mean is that over time, as you ride an aluminum frame the stress upon the frame will eventually cause it to fail. Personally, there is zero chance I'd convert an aluminum frame, -especially- if I was going to be over loading it and going at faster than typical bicycle speeds. The worst case scenario is the an aluminum frame fails and you end up on the ground at 20-30mph in traffic.

A bit of food for thought, you could probably get by with v brakes on a dual motor setup using regenerative braking, or maybe just regenerative braking with that single motor you have in mind. But, you could always get a new steel fork that has a disc brake mount for whatever frame you use.

 

[2old]

+1 on BOS's suggestion; find a mid-90's steel mtb frame (or something like a Nashbar steel one - $80 on sale - I have both types on different bikes), and a "modern" steel rigid fork (Surly makes a good one) or suspension if you want (make sure it doesn't have a tapered steer tube). You'll have the best of both worlds.

One question --- did they weld steel dropouts to an alloy frame --- I've never seen that before?

 

[lowquality]

Ive basically wrote my current bike off as a contender, and others said they wouldn't use it on another forum and i accepted that. I figured you guys would have more experience and could tell me correctly. I figured if i enjoy riding i might put a 500w motor on this bike so friends or wife could keep up and have fun also.

 

[lowquality]

There were a few bikes I was looking at, this is one of them

http://www.trekbikes.com/us/en/bikes/mountain/sport/820/820/

Sorry I am not knowledgeable about changing bike parts, but let me see If i understand - correct me if I am wrong.

So If i buy the Trek 820. Then I will need to find a front fork, much like this one perhaps? (having a hard time finding one in steel :| ) http://www.jensonusa.com/!N87gHOyDGJAA4W-u5eQ9kA!/Surly-Instigator-Fork?utm_source=FRGL&utm_medium=organic&gclid=CjwKEAjw7O6vBRDpi7O-8OWSkwESJACNFsgxMesf9ySfxIwHT0471SNg6H22g412-n3mJixDvFGJlxoCStLw_wcB

then simply add http://www.jensonusa.com/MTB-Disc-Brakes/Shimano-XT-BR-M8000-Disc-Brake (just random one) and Its a wrap correct?


I'd assume the 29" front fork would not work but its the only one made in steel, but since the hub motor is in the rear, its the only one that needs to be steel anyways id assume.


SO the answer seems to be neither - just get a steel frame and buy the parts needed to install a front disc brake.

 

[2old]

The 820 is a perfect platform (IMO); the spec sheet doesn't indicate the wheel size, but look at the Surly web site for the appropriate front fork, or you may be able to locate a Rock Shox XC 32, a decent suspension fork for light duty, for $100 or so.

 

[Ykick]

Although somewhat “exotic” Magura hydro rim brakes are very impressive for non-disc frames. The braking power and modulation on a decent rim under good traction is damn near unbelievable.

They turn up on eBay and PinkBike every once in a while cheap enough and along with a few tools to deal with bleeding and setup, they’re rock solid and Clark’s makes a good cheap replacement pads.

Difficult to setup brake switches on any hydro system but if you can workaround that and you’ve got a frame with only V brake lugs, take a look at Magura hydro rim brakes.

 

[2old]

Also, now that I've checked on your bike, the frame is steel not aluminum. Many individuals use pretty high power motors on more cheaply manufactured frames it. Hopefully, the more expert individuals will chime in on whether the frame is adequate (you might ask Eric @ Luna; I've found him very helpful in coordinatine his components with my platforms).

 

[lowquality]

Also, now that I've checked on your bike, the frame is steel not aluminum. Many individuals use pretty high power motors on more cheaply manufactured frames it. Hopefully, the more expert individuals will chime in on whether the frame is adequate (you might ask Eric @ Luna; I've found him very helpful in coordinatine his components with my platforms).

You mean the trek right? My releigh is atomic aluminum - guess atomic is the bomb when it comes to aluminum

 

[dogman dan]

You could ride quite safely by looking ahead. After all, if you are desperately locking up brakes to save your life, you screwed up at least a half a block back there. If a car surprises you, it's entirely your fault. Ride safer routes, the long way is easy with ebikes.

What I mean is, sure your bike may go 30 mph, but good brakes or bad, you ride it 30 mph in the wrong place, you die. Shitty rim brakes plenty adequate to stop from 30 mph when in a place where riding 30 is safe. So yes, get a brake upgrade, but don't depend on brakes to save your life. Depend on anticipation, and evasion. Stopping distance will never ever be short enough.

I'd say, use that bike. (the atomic) It's fine with two torque arms. Eventually do a conversion to give it a mechanical disk front brake, since the mounts are there. Nothing fancy, but the disc wheel will cost a bit of cash. But it should be possible for $100 or so. When you do need a maximum braking, the front wheel has all the traction, so making that wheel disc worth it IMO.

But meanwhile, just get good pads for your rim brakes, and ride smart. I did years of commuting 30 miles a day with nothing but rim brakes. And with bikes able to go 30 mph too. Only when I started seriously riding off road did I really crave better brakes. I don't brake out of trouble, I swerve. So brakes just stop me for the light, no more.

 

[nutnspecial]

I agree with most everything said, but still wouldn't recommend a 280lb rider (that seems inexperienced espec) to feel safe on a '270lb' bike, plus the 'e'.

We had 820's and 830's awhile back, and they're awesome cromoly bikes, but at least some have a 1" steerer, so suspension is pretty much out, and especially with a heavier rider, I'd think some shocks would be great.

 

[lowquality]

I have decided to no use the Releigh as among other things, its just too damn tall and not comfortable to ride (went on a bike ride today) gotta stand on my tip toes at red lights Plus I want to do it right.


So I do believe I have narrowed it down to 2 choices, depending on which is in stock.

A shop about 30 miles from me is a Trek dealer, so obviously the 820 is my #1 choice - but if they don't have any or have problems getting one -

My local shop only sells Kona or kHS - and the only frame that is steel is this one - http://khsbicycles.com/bikes/2015-khs-models/alite-40-15/

This is the battery pack - just from looking it would appear to fit well on the 820 - http://lunacycle.com/batteries/packs/triangle-48v-samsung-18650-20ah-pack/

I'll bring a measuring tape, but if it doesnt fit I think I'll just invest in making homemade clocks....






Okay - since the 820 is %90 what I'm going to get - anyone feel like doing my leg work for me and finding me a suitable new front fork / decent quality disc brake (do not want hydrolic ) or what would I need to do to get the bike in perfect condition.


Oh and on a side note - If i simply found a used trek aluminum bike on craigslist used, any way I could just take the front tire/fork and stick it into my steel framed 820 since the motor is on the rear.... that might be cheaper if it works

 

[2old]

You might be able to locate a bike with a decent fork, wheel and brake, then swap with the 820, and sell the other bike to recoup some of your expenses.

 

[docw009]

If you want simple, why not consider a mid drive kit. You'll have to get the crank puller and bearing remover, but these are under $15 on ebay for the pair. I just did a rear wheel drive and needed the tools anyway to install the pedal sensor,

WIth the rear drive kit, the controller is integrated. All you need to do is mount the display console and brake levers. While I've never put one together, it looks straight forward.

On my recent rear wheel build, the frame needed to be spread to fit the wider wheel assembly. Good thing I had a steel frame. These kind of problems don't come up with a mid drive. There's no worry about cheap torque arms coming loose. You keep all your brakes and suspension as is.

Here's a recent thread, where the OP says he has the power you want.
https://endless-sphere.com/forums/viewtopic.php?f=28&t=72593

 

[MadRhino]

Personally, there is zero chance I'd convert an aluminum frame, -especially- if I was going to be over loading it and going at faster than typical bicycle speeds. The worst case scenario is the an aluminum frame fails and you end up on the ground at 20-30mph in traffic.

More chances are that a failure induced crash happens with a steel frame, in mountain trails especially. A crack in an alu frame doesn't send you off track, but a bend in a steel frame does. When DH bikes were steel, it used to be pretty often that a chainstay bent at landing or crossing a root garden, and that does wash you out of the trail To make the same stiffness and reliability as modern Alu DH racing frame with steel, you need a motorcycle frame.

It is a myth that steel frames are better than Alu. This is true only with cheap frames like Wallbikes. If you are gonna buy crap buy steel crap, not because the alu crap could fail and cause a crash, but because steel is cheap and you are likely to have a better bike for your 200 $. Then, if you are gonna overload a bike and ride it at motorcycle speed, building on a cheap frame is for those who value their wallet better than their skin and bones.

 

[bowlofsalad]

Personally, there is zero chance I'd convert an aluminum frame, -especially- if I was going to be over loading it and going at faster than typical bicycle speeds. The worst case scenario is the an aluminum frame fails and you end up on the ground at 20-30mph in traffic.

More chances are that a failure induced crash happens with a steel frame, in mountain trails especially. A crack in an alu frame doesn't send you off track, but a bend in a steel frame does. When DH bikes were steel, it used to be pretty often that a chainstay bent at landing or crossing a root garden, and that does wash you out of the trail To make the same stiffness and reliability as modern Alu DH racing frame with steel, you need a motorcycle frame.

Good morning happyrhino.

Shoot, now I gotta wipe the barbecue sauce off my fingers. Hooray, people are paying attention to me! I think your argument is heavy in anecdotal evidence. You are referring to a situation where the number of variables from scenario to scenario is infinite. Retrofitting or converting an electric bicycle is a bit different than using a bicycle frame for it's intended purpose, apples to oranges. Taking an aluminum frame and using it for a purpose well beyond what is was originally designed for can be very bad, as I mentioned. I am certain though, that people have crashed just the same from a failed aluminum frame in your scenario just as they have crashed from a bent steel frame, but neither is ideal, nor should either happen and isn't the materials doing (sounds silly to even imply).

It is a myth that steel frames are better than Alu.

You are putting words onto my fingertips, I am writing on a specific idea. You can design aluminum electric bicycle frames that will never reach minor stress amplitudes which will never result in frame failure, it'll just weigh and cost more than other materials. I didn't say a thing about one material for framing being inherently superior to another. At best, I implied only what you stated.

This is true only with cheap frames like Wallbikes. If you are gonna buy crap buy steel crap, not because the alu crap could fail and cause a crash, but because steel is cheap and you are likely to have a better bike for your 200 $. Then, if you are gonna overload a bike and ride it at motorcycle speed, building on a cheap frame is for those who value their wallet better than their skin and bones.

Basically you are paraphrasing what I am saying but adding a twist so to turn the discussion into a steel versus aluminum debate and ignoring fatigue limit for reasons I won't speculate upon. Just like most here do not recommend using aluminum drop outs because they will eventually crack and fail sometimes resulting in injury or worse is the same idea for OPs given scenario. Imagine a fatigue limit joint failure at the bottom bracket while going 30mph. You can argue that that the steel frame might bend and maybe one guy would catch themselves where the next guy might not and yadda yadda. But in my imagination the steel frame bending, much like the steel dropouts slowly or swiftly being splayed and the axle spinning in the dropouts, is wildly better than fatigue limit failure where things fall apart in a sort of sudden and potentially extremely unforgiving way.

I think it's absolutely worth putting heavy emphasis upon this idea, otherwise I wouldn't be writing this. Fatigue limit is not something to ignore or take casually, though some companies make their high end frames with weight and marketing rather than longevity and reliability in mind and so you still see pointless and dangerous frame failures as you mentioned. Some folks simply assume the word aluminum or alloy(most don't know the definition of the word alloy) means quality and so it's in vogue to make frames out of that material, banking on various false assumption like aluminum is inherently better in certain ways I don't feel are necessary to drivel on about. Just as you noted, the guys who are turning their bicycles into electric bicycles are very likely much better off doing so with a steel frame. I didn't mention this before because I am sure this is sooo obvious, but what is likely the right course of action is to buy or fabricate a frame for it's intended application. If it was in OPs budget, it sounds likely that that is what he would do, saving dollars for a little while is probably going to be much cheaper than a single hospital visit as well as much more pleasant, but I suppose he is simply making best with what he can and wisely heeding the words and advice of others.

http://em3ev.com/store/index.php?route=product/product&product_id=209 This might be an excellent example of a frame to use for an electric bicycle, seeing as how that is what it is designed for, though with shipping it sounds to be a bit beyond OPs budget (official numbers are precisely $500ish). Made out of 'cheap' steel and even includes fancy shmancy disc brake mounts.

 

[Drunkskunk]

The 820 is a great bike. The 800 series in general is what I would recommend almost anyone as a first bike. They are also plentiful and often a used one can be found cheap on craigslist. Since you will be replacing a whole wheel anyway, why pay for a new bike?

The 820 is different from the 800 in that is does have a suspension fork. Unless the motor is mounted to the fork, Aluminum is fine. the best forks are aluminum. Aluminum is used in aircraft. The last B52 was built in 1962. Currently the USAF plans to continue using the B52 until 2040, when the youngest B52 in the fleet will be 78 years old. Aluminum does fatigue over time, but you aren't likely to wear a decent set of forks out this decade. Probably not in the next 2 or 3 decades, either.

Unless you plan to exceed 30mph, or you have many steep hills to descend, you don't need disk brakes.
As long as the brake is capable of skidding the tire, then Braking power is entirely a factor of the tire's grip on the road. There is no difference between a rim brake and a disk in terms of stopping power.

Rim brakes offer better modulation at low speeds. You'll often see urban stunt bikes fitted with rim brakes instead of disks because it affords better low speed control.

 

[lowquality]

I found a new 820, the only used one i could find was only $75 less and and hour away.

My motor should be in monday, I'll prob frock up the installation and come begging for help thx for the input.

 

[nutnspecial]

Cool nice buy!

Well, we'll be here,
with a wealth of knowledge and just the right amount of contradiction :lol:

Have fun, peace!

 

[lowquality]

Okay, So quick question perhaps someone can shed some light.

I tried to install the motor on the rear tire, but the second i tighten the nuts on the motor/tire, the free wheel will no longer turn.

AFter trying to do a few things i gave up and brought it to a local bike shop, they said they've installed a few motors before and shouldn't be a problem. Well they got the motor working fine, but low and behold they can't make the free wheel spin. What could be causing this?

Our solution is to take off the 8 speed free wheel i ordered from lunacycles and use the original 7 speed free wheel that came on my bike. If that doesn't work then they suggested using a front crank system whee the free wheel is where you pedal.

Bright side - the motor alone could carry my fat butt around pretty fast.

 

[bowlofsalad]

Chances are the 8 speed freewheel is coming in contact with the inner portion of the dropout. Usually when I hear about freewheel compatibility for hub motors 7 speed is usually what is noted. Freewheels with different gear counts have different widths. So the 7 speed notion sounds likely to sort things out for you.

On a mildly related note, while riding electric bicycles I don't do much shifting, I rarely, if ever, touch the freewheel gears even when using something like a 300w power limit. A lot of people imagine they will do a lot of pedaling of their electric bicycle with just pedal power alone, but pedaling electric bicycles sucks without electric propulsion. The extra weight and cogging are a real drag, I pedal with the motor always. The point I am trying to make is, I use 6 speed freewheels and really only have it there as an option to consider for limping home with a dead battery or busted controller or something otherwise I'd be using single speed freewheels.

 

[Snurt]

Learn to weight shift and to stoppie when braking. It will do more to your stopping distance than any basic design or frame material combo.

Also depends on your breaking, I say go with whatever, I'm at 275lbs person and I'm able to do a endo and stoppie with both V's and Disc's, tho I feel that i need almost XTR V's to match Zee rotors.

First and foremost, learn to maximize the brakes u have, weight-shift then use the back brake to its limit then supply with front brake to stop as fast as possible.

Maybe you know all this already, and if so I am sorry if I seem like an ass to point it out.