built_not_bought
New Member
Im 360Lbs and ride daily !!!
Bikes for heavier people?
- Thread starter Holly
- Start date
Steve Best
Well-Known 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.
Steve
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.
Steve
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.
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.
FurryOnTheInside
In Memoriam
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.
libranskeptic
Member
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- Jan 13, 2016
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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.
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..
Steve Best
Well-Known 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...
FurryOnTheInside
In Memoriam
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!
((Front brake is an old favourite Hope C2 #3, hydraulic, 203mm (2-piston closed system). eBay £15!!
))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! Hub motors unfortunately preclude the use of a single wheel trailer, otherwise I would love to have one and I love the idea!
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FurryOnTheInside
In Memoriam
Seat height adjustment!
Also I get chaffing from chunky bicycle seats because of my fat thighs.
And ALL branches of the bicycle building rabbit hole are bottomless! n=n+1 as they say!!!
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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.
