Bikes for heavier people?

Discussion in 'General Questions' started by Holly, Aug 27, 2016.

  1. Holly

    Holly Member

    I have a friend that thinks my bike is the best thing ever. She said she wants one too but says "bikes break when they see her coming".

    I don't know how much she weighs exactly but I do think she would need a bike that would be sturdy enough for her.

    I'm guessing a step through frame would be best for her so possibly a rear mount engine....


  2. jaguar

    jaguar Well-Known Member

    a step-thru frame would be the first to bend under a heavy rider
  3. Holly

    Holly Member

    Makes sense.

    I was considering that I don't have an easy time getting my leg over, though I've got a basket on back that doesn't make it easier.
  4. bakaneko

    bakaneko Active Member

    The other selling point for the friction drive is that it is very easy to set up with the 4-stroke motor however it is much more expensive. the other question is if there are a lot of hills around your area or more flat roads. I never used a friction drive but I think they might not provide as much torque as a inframe engine. You can change the friction rollers for more torque but it might not be as good as an inframe engine to a rear sprocket.

    this might be important because if there are a lot of hills and if your friend is heavy she would want to focus more on torque versus speed. hopefully, someone with experience with different size rollers for friction drives can speak about this. for inframe, your friend can just get a lower sprocket 56t or so. I dunno. I really like 4-strokes but they do not have as much raw power as 2 strokes but the maintanence and installation is minimal.
    Holly likes this.
  5. Frankenstein

    Frankenstein Active Member

    Well the type of bike has a lot to do with it, like an actual mountain bike made for trails or jumps would hold, steel over aluminum obviously. I'd say older bikes would be better, they are usually built tougher (note by the way the old frames weigh 30 pounds vs today with lightweight designs.) so I am 210 with a dented downtube for my muffler to clear. It's also steel and it's got a 2 inch downtube. It took a lot of hammering to get it dented.

    It's a mongoose terrex. Has front shocks which help take some of the beating off the frame.

    Look for a shorter wheelbase, as in smaller distance between where the wheels hit the ground. The smaller the distance between them generally the more sturdy the bike will be towards more extreme riding circumstances (note those little Bmx trick bikes, the small wheels and frames and wheelbases allow for more shocks without tearing the frame in half)

    Not to be Uhm... Rude? But if she's so heavy she's actually breaking bikes I don't think putting a motor on it will help the cause, unless she plans on pedaling with it, which for all I know she may very well have to. I know that after I put a motor in my bike I definitely didn't start losing weight... I did however gain a few extra..

    Anyway, 26 inch or smaller, smaller wheel base, and heavy steel frame, that should hold up to most people, if she has a problem with popping tires (which I did) go with the fat tire bike like a terrex, I know there are several types of bikes with fat tires, I'd suggest a steel huffy called the fortress, has 3 inch tires, cheap enough to be affordable, and after looking it over rather extensively I can see it being a suitable bike for a larger person.

    I'll also note my father in law is close to 400lbs, he was able to ride my bike without it becoming scrap metal.

    Good luck and it's nice to see a girl on here once and a while, still trying to get my sister to sign up so she can solve her own problems.
    Holly likes this.
  6. Holly

    Holly Member

    Great info thank you! I'd guess she's between you and your father in law's size (but don't quote me because I really don't know). I don't think she's broken a bike rather just hasn't gotten on one being self conscious. She drives a car so this would just be recreational for her.

    It's moderately hilly here. I should say it's down hill one way and up hill back because we live on the coast.

    I'm going to look up your mentions and see if I can piece something together for her.

    And tell your sister to sign up! You guys are amazingly helpful but it would cool to see other girls too.
  7. Frankenstein

    Frankenstein Active Member

    It's always uphill one way and downhill another, in the end you're just trying to get somewhere, and there should be one best way to do it, don't forget that.

    So if she was pushing 300lbs but not planning to jump over crazy shit with it she could do with a bike rated for a 200lbs rider on a design meant for mountain trails, including the stuff that comes with it.

    Remember the manufacturer tests untill it breaks, then tries to determine what size rider can break those bounds. A strong beefy fella who weighs 200 pounds could put a mountain bike through some serious hell if he's using his muscle. A 300 pound woman who isn't going to use it much past luxury will never put the bike at it's (true, like actually a 300 lbs beefy rider on a downhill mountain course) limits.

    I've got a very powerful motor and am at the basic limit of my bike weight wise, but I use it on primary road surface, never had a frame problem. I've also taken it off the beaten path without any issue beyond my lack of control on those types of terrain with a bike I'm not used to riding on that type of terrain.

    I'd say most bikes will be OK, like I said, the manufacturer has to legally put a limit on the bike so they can minimize lawsuits. If they say any ol' Joe schmoe can ride the bike then they are opening themselves up to a shitstorm of legal problems. (think how putting a limit of 200 lbs riders and only for on road use protects them, when most of the sue happy American population will weigh more than 200 lbs and most accidents not caused by vehicles will happen off road...Yeah, gotta love lawyers)

    Also limits are set often by the drivetrain, being that a chain and sprocket usually drive the bike, limiting a person's size can set a top end force requirement of the derailleur and chain and sprocket. Just because the frame can hold a 500 pound man up doesn't mean the chain and sprockets can handle his force output. So limits get set on the cheap plastic drivetrain components as well. Since a motor will be driving the bike it's probably useless to care about the requirements for the person.

    At this point the only important factors are a decent steel frame that can hold up to the motor itself and it's vibration, along with a rear wheel with spokes that can also handle the torque produced by an engine that's pulling the person. Beyond that it's imagination that limits the bike, not necessarily physical size of the rider.

    My bike has an upgraded drivetrain, jackshaft, nuvinci hub, heavy gauge spokes. Everything else is stock and according to the manufacturer my bike with a huge dent in its frame should've folded under a 400 pound man, yet it didn't.

    Good luck, make sure she wears a helmet, no matter how ugly it makes her feel, it's still important.
    Holly likes this.
  8. bigkev81

    bigkev81 Member

    Hey Holly,
    I'm a heavy bloke. I weigh around 140kilos (I've put so much weight on the last 5 years its embarassing, lol)

    Anyways, my 66cc 2 stroke seems to carry me just fine. I easily coast at 35km per hour most of the time. I can go faster but I dont as my engine is still breaking in, and I had a nasty accident on my bike 3 years ago which kind of killed the speed demon in me. My area is fairly flat so I haven't tried uphill yet, so I can't comment on climbing.

    I hope my input helps with your question. :)
    Holly likes this.
  9. BakkenRide

    BakkenRide New Member

    i'm not skinny, actually i.m pushin 270 and my firmstrong cruiser has held up fine the last couple years at 30 mph. although i did change from 14 gauge (spoke) rag joint rear wheel to 12 gauge disc brk. mount sprocket rear wheel, when i took the sprocket off the old wheel most the spokes were broke , it could of collapsed.
    Holly likes this.
  10. Holly

    Holly Member

    Thanks guys! Great responses that I'm looking forward to passing on to her.
  11. built_not_bought

    built_not_bought New Member

    Im 360Lbs and ride daily !!!
    Holly likes this.
  12. Steve Best

    Steve Best Active Member

    I'm 210 lbs but I was pounding my Mountain bike at 30-40mph on rough back roads and trails. Took some serious hard bangs without damage to frame, rims or spokes. I did burn the bearings out of the back wheel. Was $30 to get bearings replaced and wheel trued and tensioned at a bike shop.
    Fat tires really help. Cheap front shocks (springs?) don't do much for comfort but take the sting out of unexpected potholes. Keeping the spokes tensioned is crucial. I do it with a dial indicator but a piece of wire twisted from the frame just about touching the wheel will tell you if it is true. The "PING" of the spoke tells the tension.
    Loose spokes will cause the tight ones to break. Overtightening is bad too.
    I dial the sprocket too, while tightening its bolts. Very easy to get it quite true. I actually like the ragjoint mount:
    This bike is a standard cheap lightweight multispeed which is holding up well with a 48cc engine, but I am riding slower (20-30mph) and on smoother terrain these days.
    I have a fat tire (2.10"?) on the front and am wearing the tread off this well weathered standard (1.75"?) rear tire.
    Notice the "8.8" on the head of the shiny sprocket bolt. That is the metric bolt strength spec and means that it is a standard automotive strength spec sort of equivalent to SAE Grade 5. That is plenty on these bike. No need for "Grade 8" or higher Metric rating. I was able to dial sprocket and wheel in to 0.010" which is quite close for what they do and improved braking smoothness considerably.

    I guess my point is a Mountain Bike frame is the most durable, but it is the rims and spokes that are most at risk.
    Fat tires help, avoiding the potholes, and keeping the spokes tensioned. I like my wide seat too, I'd recommend getting one.

    Holly likes this.
  13. built_not_bought

    built_not_bought New Member

    I have a rim graveyard... I have a few things going for me with all these spares I tweaked, 1. Spare parts 2. I reuse the aluminum and cast my own parts (Self taught) 3. Lived and learned.... Ive recently upgraded to some rims I found online made for MBs, work really good. 20160831_142426.jpg received_1840408772848985.jpeg
    bigkev81 and Holly like this.
  14. JunkyardDog

    JunkyardDog Active Member

    I weigh 240. I am using a friction drive on a Felt Bixby 7 speed. The main problem with cheap bikes is the wheels. I have bent a lot of rear wheels, and had broken spokes. So far no problems on this bike, but I haven't ridden it on really rough surfaces yet. Potholes will kill a wheel quick. the best way to go is probably get a rear wheel for a downhill mountain bike. You can buy them, or a good bike shop can build you one. It won't be cheap. Expect to pay several hundred dollars. These wheels are designed to take a serious beating. I've seen downhill mountain bikers going over ten foot drops. Walmart steel Huffy frames tend to be fairly strong. But "Roadmaster" frames are not. Avoid these at all costs. Same with "Magna" bikes from Target. And stay away from aluminum frames. High dollar downhill mountain bike frames are made out of titanium, but those are pretty much out of the price range for a typical motorized bike.
    Holly likes this.
  15. FurryOnTheInside

    FurryOnTheInside Active Member

    Several hundred if you buy new stuff; but I got a pair of 26" wheels, 36 spoke front and 48 spoke rear. £76 off ebay.
    Rims are Halo SAS : double stainless eyeletted, double wall box section, pinned and welded, 30mm internal 36mm external width downhill/dirt jump/BSX/tandem rims.

    The front is older, with the Diatech hub, it is a cartridge bearing hub that takes 20mm thru axle or a QR adapter.
    Rear hub is the Halo Spin Doctor also a cartridge bearing hub with four easily replaceable sealed bearings (two in the hub, two in the freehub) and QR. I have a (new old stock) 48 hole Hope Big Un rear QR hub to replace it if and when it fails.

    I also got a 24" Alienation Runaway double wall BSX/jump/trials rim on a Hope Big Un rear hub with 36 stainless plain 14 guage spokes and it is SOLID. The cross section is concave so the spokes cross the centre for extra lateral stiffness, but it is not eyeletted. £53 off eBay.

    I plan to modify my trailer (with the help of a welder) so it can take a 24" and 26" rear wheel, then I can swap the wheel when I need the 24" on the bike. It should give me extra low gearing because of the smaller diameter and I will use a more off-road oriented tyre. :)
  16. libranskeptic

    libranskeptic Member

    Interesting concept swapping wheels for strength & gearing. How do back brakes work?

    I have had similar ideas of swapping wheels and using them as a "power takeoff". The substitute "wheel" is a circular saw or a pulley winch etc.

    a petrol powered rear wheel which also contained a hub motor with regen, could generate electricity in the field, by spinning it while stationary..
  17. Steve Best

    Steve Best Active Member

    If you start down this rabbit hole you start to wonder why you don't just put a pedal crank on a small motorcycle or scooter...
  18. FurryOnTheInside

    FurryOnTheInside Active Member

    Not really for strength. The SAS 26" rims are easily strong enough so I doubt the extra strength of the smaller diameter and "trans offset" (I just made that up) eyelets will be nesessary, but nice to have.
    Even nicer though: to have a more dirt-oriented high volume, low pressure tyre ready to go straight on. Also can be fitted if the pawls in the Halo hub fail (I'm saving for a shift kit, if I can stop buying too many bike bits!) from motored use, to get me home to replace them. :)

    The brake on the rear will be a cable disc, cheap one I already have, upgrading to a dual "piston" later. I will need to use an A2Z disc brake adapter to attach the caliper to the old GT LTS-5 cromo frame. I have the option to develop a disconnectible trailer brake sometime, too! :cool:

    ((Front brake is an old favourite Hope C2 #3, hydraulic, 203mm (2-piston closed system). eBay £15!! :D ))

    Ooh! So you mean like maybe a hub can be used as the spool of a motorized fishing reel for longline shore fishing? :) Kite takes it out, engine brings it in! That would be so cool! :D

    Hub motors unfortunately preclude the use of a single wheel trailer, otherwise I would love to have one and I love the idea! :)
    Last edited: Sep 3, 2016
  19. FurryOnTheInside

    FurryOnTheInside Active Member

    Seat height adjustment! :p
    Also I get chaffing from chunky bicycle seats because of my fat thighs. :oops:

    And ALL branches of the bicycle building rabbit hole are bottomless! n=n+1 as they say!!!
    Last edited: Sep 3, 2016
  20. JunkyardDog

    JunkyardDog Active Member

    If you are building a motorized bike, you ARE building a small motorcycle. Adding a motor to a bicycle designed to be powered by pedals puts more stress on it than it was designed for. And if you are going faster than a pedal bike, and hit a big bump or pothole, the whole bike might come apart. The wheels will definitely be crushed if you hit a pothole, with the liklihood of a serious crash. If you plan on never riding above 10 mph, and weigh under 200 pounds, you're pretty safe with a cheaper bike. But when rider weight gets close to 300 pounds and speeds approach 30 mph, you are way beyond the limits of an ordinary bike. Downhill mountain bikes are the strongest bikes made, so it makes sense to use components from them for strength. Many professional downhill mountain bikers destroy parts on a routine basis. If you want to know why, just watch a few downhill mountain biking videos on Youtube.

    Hopefully nobody would try to ride a motorized bike like that. But I would still get the strongest parts you can afford. Worksman makes probably the best regular bikes you can get. They are designed for commercial use. The frames are super strong. Depending on your weight, speed, and what kind of surface you are riding on, you may still need to upgrade the wheels.

    As far as brakes, the main thing is to have a good FRONT brake. It is very easy to lock up a rear brake in a really fast stop, and because of forward weight transfer caused by inertia, the back wheel may even come off the road, resulting in a total loss of traction. 90% of a vehicles braking power in in the front brakes, and that number increases the faster you try to stop. The most efficient braking is achieved when you hold the front wheel on the verge of lockup. That takes practice and experience.

    Comsidering what some people are building here, I often wonder why they don't just get a small motorcycle or scooter. You can get a nice used one for what it costs to build a decent motorized bike. I have close to $1000 into my MB, and it is a friction drive. About $350 for the bike, Another $350 for the engine and friction drive mount, then close to $300 more for high dollar tires, thorn resistant tubes, Ride-On in the tubes, good lights front and rear, a tire pump, pannier on the side opposite the engine, and a few other bits and pieces. I could have easily bought a 50cc non Chinese scooter for that, that would safely go 40 mph and carry 350 pounds.

    But I wanted a bicycle, because I used to be a cyclist until my health issues made pedaling any distance impossible. I already have two 200cc scooters, a 150cc scooter, a 225cc dual sport motorcycle, a 500cc street bike, and a 750cc street bike. I no longer have one, but I have had many mopeds (actual '70s style pedal mopeds) Puch, Tomos, Motobecane, Peugeot, etc.
    FurryOnTheInside likes this.