Using Automotive engine belts in leiu of chains?

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Jun 15, 2019
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So an upcoming build I have in mind likely generates too much torque to adequately use a chain, but I'd rather not blow several hundred dollars on a cog belt system like a VEER when similar cog/V belts have been used for decades by OEM car manufacturers in engine valvetrains. So has anyone here used them as a replacement? I think a 1UZ-FE V8 timing belt should be long enough for this idea but i'd like to get some outside inspiration.

EDIT: Forgot to add, I'll use an IGH with this idea so the belt will have no derailleur thingamathing
 
CONSIDERABLE SHOUTING said:
So an upcoming build I have in mind likely generates too much torque to adequately use a chain, but I'd rather not blow several hundred dollars on a cog belt system like a VEER when similar cog/V belts have been used for decades by OEM car manufacturers in engine valvetrains. So has anyone here used them as a replacement? I think a 1UZ-FE V8 timing belt should be long enough for this idea but i'd like to get some outside inspiration.

EDIT: Forgot to add, I'll use an IGH with this idea so the belt will have no derailleur thingamathing

Chains reliably transmit more torque than belts, and more than enough to break internal gear hubs. My observation from dealing with people’s belt drive bikes at the bike shop is that belts wear out a lot faster, are happiest with high tension that damages the bike’s other parts, and cost a lot more to replace.

If you really think your machine will tear up a normal bike chain, then try a heavier but compatible roller chain like #410, 410H, or 415. But in that case, God help your IGH.
 
eee291 said:
https://endless-sphere.com/forums/viewtopic.php?f=10&t=94666

Thanks! I'll take a look.

Balmorhea said:
Chains reliably transmit more torque than belts, and more than enough to break internal gear hubs. My observation from dealing with people’s belt drive bikes at the bike shop is that belts wear out a lot faster, are happiest with high tension that damages the bike’s other parts, and cost a lot more to replace.

If you really think your machine will tear up a normal bike chain, then try a heavier but compatible roller chain like #410, 410H, or 415. But in that case, God help your IGH.

Really? Everything I've read from threads here implied the opposite- especially with the cyclone 3000w motors.

I only bring up the IGH because if I don't shift while accelerating the motor I won't 'shock' it, but I'll admit part of my desire to do so is perverse desire to see what it's pain tolerance is.
 
Motorcycles have hundreds of horsepower (lord only know how much power the Super Bikes put out), so a chain will take more power than you will ever put through it w/ an electric motor. You'll want to go to motorcycle type rims, spokes, gears etc if you are gonna put a ton of power through a bicycle, which is probably a sub optimal idea in the first place. Automotive engine belts are specific to their application. They don't deliver horsepower to the road, they just spin camshafts.
 
OK show us your calculations where you prove that even a bicycle chain will break under your application and I will show you that you are WRONG.

Seriously go on show me the numbers.
 
You're focus is on the wrong thing. The weak point will be the IGH regardless of whether you run a belt or a chain.
 
CONSIDERABLE SHOUTING said:
EDIT: Forgot to add, I'll use an IGH with this idea so the belt will have no derailleur thingamathing
Realistically, if a singlespeed chain is unable to handle the torque, the IGH is unlikely to either.

An IGH will have some component in it that will shear or break at torque below that which would destroy the gears, etc., like a shear pin. So...you can probably repair it once it breaks, but it'll require some disassembly. The torque limit of the IGH you're using should be published by it's manufacturer, for that model/year/brand, so you can know what not to exceed.

But if you are exceeding it....
 
I can get you a ton. Small belts, big ones, wheels, from the industrial scrap yard.

Harleys use belts. Rocketbikes eat chains like a mid drive bicycle too. Lol. One or more per season. Blah. 520 wears on a 1000cc bike just like a 10 speed wears on a BBS02.

Hogs.. use belts for some reason. intrigued me. Imma thinking about sing one on a build actually.. cause I hgave access to pretty much a timing cog and wheel zoo. i was doing a Subi timing belt yesterday and I was thinking about it.

Chains wear out. Its why many sport tourers come OEM with 530 chain oring and the hot rod thing to do is go 520 on a rocket bike.. and replace every year. Blah I have a pile of stretched 520 and sprockets. Like aluminum sprockets.. they work.. but are replaced often.

In industrial application the chains for driving conveyors and whatnot are always over engineered and very tight tolorence. Belts are strong and accurate enough to make CNC machines with.
 
Question on belt/chain is not which one can take your torque. Either one, properly sized, will work.

Chain
Cheap sprockets and chains
Easily available
Easy gear ratio changes
Alignment and tension is not critical
Slightly more efficient
Smaller width for same power
Works offroad

Noisy
Dirty
Maintenance intensive - has to be lubricated
Heavy

Belts
Silent
Clean
NO Maintenance
Lightweight

Expensive pulleys, hard to source
Expensive belts
Difficult gear ratio changes
Alignment and tension is critical
Slightly less efficient
Wider for same power - can be hard to build clearance
Does not work offroad

As for the harleys using belts, i think this is due to the massive load peaks and vibrations of the large v-twin engines. In this application belts are probably superior as they have some damping.

In my use, street commuting, i find the belt to be superior but the initial cost and design difficulties has to be overcome. I just switched to chain drive again to play with the gear ratios but likely i’ll go back to belt when i know what ratio i want.
 
larsb said:
Belts
Silent
Clean
NO Maintenance

By the time I see them, they're not any of the above. Based on feedback from disappointed owners, it seems that an unlubricated chain and an unlubricated belt last about the same amount of time-- but only one of the two can have its life extended with lubrication.

Yes, if you go to a toothed belt 40mm wide, you can beat the expectations I've developed for these things. But a belt that fits in the same space as a bike chain, is going to dramatically underperform a bike chain.
 
Never lubed a belt.. why would you? If sidewalls are rubbing then alignment is not good or mounts are flexing too much.

The problem with mid drive belt reductions are mostly that people use too small belts, poor wrap angles, too small tooth count, double bending etc outside of manufacturer recommendations. chains can take this kind of abuse more easily and you’ll ”only” get excessive chain and sprocket wear and not tooth skipping or ripped belt.

It’s poor engineering basically.
 
larsb said:
Never lubed a belt.. why would you? If sidewalls are rubbing then alignment is not good.

What I'm saying is a dry belt apparently lasts no longer than a dry chain. But in my observation, it skips easier, wrecks its sprockets faster, and can't be improved by maintaining it.

If belts were half as good as chains for bicycles, they'd be common. It's not like they haven't been around the entire time that bikes have been developing.
 
For bike use the obvious downsides are belts need proper tension / loads the bearings more, need tight tolerance wheel position and the stiffness of the belts haven’t been enough until recently, it cannot be used with derailleurs etc.

They are more expensive and complicated for the user to set properly so chains are the more robust and obvious choice.

—> Downsides are the same but the user can often be a nincompoop. Hopefully any diy:er has a higher technical level and can set the belt tension and alignment properly.

What is not obvious on bikes are the the torques are enormous compared to most motors. A fit rider can put 1500N*0.175m, that’s 262Nm on the crank.
 
momus3 said:
Motorcycles have hundreds of horsepower (lord only know how much power the Super Bikes put out), so a chain will take more power than you will ever put through it w/ an electric motor. You'll want to go to motorcycle type rims, spokes, gears etc if you are gonna put a ton of power through a bicycle, which is probably a sub optimal idea in the first place. Automotive engine belts are specific to their application. They don't deliver horsepower to the road, they just spin camshafts.

I was planning on using some motorcycle/coped parts already. I'm unsure if I'll stick to a bike frame or a moped frame, but that's more just based on what I find. Good to know that chains are tougher than I thought.

As for the "Just spin camshafts"- No, no no no. That belt takes the torque and vibrations of the engine and in turning the cams is working against compression in the cylinders and spring tension to keep timing for 100,000+ miles. They absolutely need to take torque, though it might not be as much as your typical gearbox.

flat tire said:
OK show us your calculations where you prove that even a bicycle chain will break under your application and I will show you that you are WRONG.

Seriously go on show me the numbers.

Pump the brakes Don Garlitz, I'm looking for advice and ideas.

John in CR said:
You're focus is on the wrong thing. The weak point will be the IGH regardless of whether you run a belt or a chain.

amberwolf said:
CONSIDERABLE SHOUTING said:
EDIT: Forgot to add, I'll use an IGH with this idea so the belt will have no derailleur thingamathing
Realistically, if a singlespeed chain is unable to handle the torque, the IGH is unlikely to either.

An IGH will have some component in it that will shear or break at torque below that which would destroy the gears, etc., like a shear pin. So...you can probably repair it once it breaks, but it'll require some disassembly. The torque limit of the IGH you're using should be published by it's manufacturer, for that model/year/brand, so you can know what not to exceed.

But if you are exceeding it....

But if I exceed it, that internal drum brake is suddenly well ventilated :mrgreen:

I've done a little research on the IGH that came with that used bulk order- it's a little smaller than the SX-RK3 that Karl on the Electric Bike blog ran some 3000w through here:
https://electricbike-blog.com/2016/01/16/sx-rk3-sturmey-archers-3-speed-igh-for-fatties-its-got-the-power-dum-dum-da-da-dum/
... and he claims other people have been running more through them; he's built a ton of stuff and clearly runs crap through the wringer, so I feel like his opinion is sound. I also know from racing that it's shock and heat that kills transmissions, not the torque itself; essentially, as long as I don't shift under load (granny-shift) it shouldn't blow. Finally, I got the thing for $~25, I've wasted more dosh on bad dates :D
Sturmey-Archer lists no torque specs, sadly: http://www.sturmey-archer.com/en/products/detail/rx-rd3

DogDipstick said:

larsb said:
Question on belt/chain is not which one can take your torque. Either one, properly sized, will work.
...(excellent info, thank you)...
As for the harleys using belts, i think this is due to the massive load peaks and vibrations of the large v-twin engines. In this application belts are probably superior as they have some damping.

In my use, street commuting, i find the belt to be superior but the initial cost and design difficulties has to be overcome. I just switched to chain drive again to play with the gear ratios but likely i’ll go back to belt when i know what ratio i want.

That's pretty much the reason I was looking at a belt- of course, that assumes I'd also learn how to deal with the tension on the frame and wouldn't have to modify it heavily to fit a junkyarded timing chain setup. I can weld no problem, but my time is money! Thanks for the info you two, that was easy for me to understand.

As for Harleys that is correct. V-twins shake horribly and the belt is needed to absorb the shock, otherwise it'd be transmitted to the rear tire. A friend of mine was given a 76' Sportster for free and we had to loctite every bolt- they all will back out from engine vibration if you don't.

Balmorhea said:
By the time I see them, they're not any of the above. Based on feedback from disappointed owners, it seems that an unlubricated chain and an unlubricated belt last about the same amount of time-- but only one of the two can have its life extended with lubrication.

Yes, if you go to a toothed belt 40mm wide, you can beat the expectations I've developed for these things. But a belt that fits in the same space as a bike chain, is going to dramatically underperform a bike chain.

I have never heard of lubing any belt- let alone an automotive belt like this idea- outside of using a small amount of grease to put moisture back into the rubber, and that's mostly due to UV rads drying it out or to limp something along.

What i'm collecting is that, while chain and gear setups will require replacement eventually they are also FAR cheaper to use and don't require tension like a proper belt setup; the amount of work to make junkyarding something like this together will likely make it just not worth it. Good to know.
 
CONSIDERABLE SHOUTING said:
I have never heard of lubing any belt- let alone an automotive belt like this idea- outside of using a small amount of grease to put moisture back into the rubber, and that's mostly due to UV rads drying it out or to limp something along.

I see belts in alot of industrial applications. Same to chains, tho.

I know of lubing belts. High power RC helis are belt driven, the high end 10Kw + ones... both the tail and the mainshaft. 3-4 min flight times and 2000~ rpm, tail runs at about 8Krpm.... Main belt is about 18-22mm and tails are about 5-8mm.. and very long ( inside boom)...

They use a static free dry lube. Swear by it. Imagine a potential 1-3K$ crash.. but the parts are regularly replace cause of paranoia or need anyway. I know alot about these setups: have thought of them when I first saw the LR and GNG kits existed. Many reductions available and known: 12-15mm shafts on most maingears and bearings.... in this rc belt driven world. The hot goblin to have right now is the belt driven Kracken: They sound quite unique: nothing like the quietness of a belt driven 6 foot heli: going 100mph through the air.... Its really quiet compared to the nylon gears ( that the other high end helis come with).....

They last a good year if you dont beat them. Common to see on 6kw + helis.

Never saw a lubed timing belt, on a car or truck...: or a 16v 4 banger rocketbike without a timing chain.... no belts for that application... Not wet lube: Dry ( graphite ) lube....

This heli can support 12Kw+ with the metal maindrive belt sprocket.
 

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CONSIDERABLE SHOUTING said:
Good to know Dog; that's pretty damn neat! Do they need the graphite lube for the tension they're under, or the speed they turn at?

I think its the speed.... they turn really fast. A silicone dry lube. alsohelps keep the static from building up on the heli in flight and zapping the electronics.. which is something the belt also does... builds static... They use Tri Flo dry lube.. or spray on food grade Silicone.
 
CONSIDERABLE SHOUTING said:
Balmorhea said:
Based on feedback from disappointed owners, it seems that an unlubricated chain and an unlubricated belt last about the same amount of time-- but only one of the two can have its life extended with lubrication.

I have never heard of lubing any belt- let alone an automotive belt like this idea-

My point is not that a belt should be lubed, but that in bicycles they don't last long enough for "no maintenance" to constitute an advantage. The periodic maintenance they require is replacement, often and expensively.
 
How do you know this..? Built a belt drive yourself following design guidelines or read about failures?

I can recommend conti-tech suite belt calculator, it’s free, think gates has one too.

I’ve run my 15kW belt drive for 20000km on two belts. Zero maintenance, fit and forget.. The difference to the constant chain lubing, rusting, cleaning and tensioning, replacement etc was huge.
 
larsb said:
How do you know this..? Built a belt drive yourself following design guidelines or read about failures?

I work in a bike shop. I see Gates, Thun, and Trek TAB belts. Most of them are hosed by the time I get to them, and many of the customers report something like, “I just replaced that thing”.

If belts worked half as well for bicycles as chains, they’d be common. They don’t, so they’re not.
 
Interesting. I see your point but the main thing for their use on bikes so far is price, gates carbon drive and the likes are extremely expensive compared to chain for little benefit. Still belts have their niche, and the bike belts aren’t representing all belts out there.
 
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