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Old 11-17-2020, 01:12 AM
staybusy staybusy is offline
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Default Belt Drive vs Chain and Sprocket vs Gears

Which is best for what use and why?

When I see a chain and sprocket on a motorcycle I don't understand why that's used instead of a belt drive or some kind of gear and shaft assembly.

Or another example: most industrial grinders have a gearbox, why not use a chain and sprocket?

I'm really an expert engineer, just testing you guys of course.
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Old 11-17-2020, 06:51 AM
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Originally Posted by staybusy View Post
Which is best for what use and why?

When I see a chain and sprocket on a motorcycle I don't understand why that's used instead of a belt drive or some kind of gear and shaft assembly.

Or another example: most industrial grinders have a gearbox, why not use a chain and sprocket?

I'm really an expert engineer, just testing you guys of course.
Did we ask you for a test ?

Try cracking a book.
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Old 11-17-2020, 08:19 AM
threepiece threepiece is offline
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Well I’m not an expert engineer but in the case for a motorcycle I suspect packaging issue is one reason for a chain. Moreover a sprocket on the rear wheel is much lighter than a gear case and shaft. This reduced unsprung weight and lowering of CG I imagine has a significant affect on the handling of a bike.
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Old 11-17-2020, 10:02 AM
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Belts do not work well below 500 rpm.
Roller chains and gears do.
Speed reduction in a small package is hard to do with belts/chains compared to gears.
And yeah, threepiece you are right about unsprung weight
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Old 11-17-2020, 10:21 AM
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Originally Posted by staybusy View Post
Which is best for what use and why?

When I see a chain and sprocket on a motorcycle I don't understand why that's used instead of a belt drive or some kind of gear and shaft assembly.

Or another example: most industrial grinders have a gearbox, why not use a chain and sprocket?

I'm really an expert engineer, just testing you guys of course.
AS for motorcycles they have used all three.
Chain... there could be a geometry issue where the swing-arm pivots and the drive sprocket... so more slack maybe required

As for drive shaft...... some one told me that the rear gear tries to climb and pulls the rider down on acceleration .... not that great if racing.

(cog/timing) belts require precise alignment or you wear the sprockets.
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Old 11-17-2020, 10:48 AM
Lew Hartswick Lew Hartswick is offline
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Someone should have told BMW years ago the gears and drive shaft can't be used on a motorcycle . :-) They just went ahead and did it anyway.
...lew...
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  #7  
Old 11-17-2020, 11:14 AM
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I had 3 motorcycles over the years. 2 chain drive and a shaft drive.

Chains are more flexible in alignment, cheaper to modify ratios, can be run open without undue wear. They are also nearly immune to slip. Chain drives tend to be bulky compared to gear drives. Chains tend to stretch and wear under load faster than gear sets. A 3 speed chain oil bath chain drive rated at 700 HP was 6' wide, 4' high, and 6' long. Quite bulky compared to the Allison automatic transmission that replaced it. Chain drives tend to be noisiest of the 3 drive types.

The positive drive of a chain or gear train lends itself to timing applications.

Belts have most of the above advantages, but are prone to slip if not tensioned enough. A belt drive may typically slip when a load is suddenly applied, or under high torque. Belts can be used as poorboy clutches, but only in low HP applications. Belts are limited in power transmission, but multiple belt drives are around transmitting several hundred HP. Those large belt drives are quite bulky. One mud pump drive I remember had a 16" diameter drive pulley and a 72" driven pulley. IIRC, there were 12 - 1 1/4" wide belts. The driver was a pair of 379 Cat engines. Naturally aspirated, they were rated at 550 HP each. Relatively recent clogged belts try to give the positive drive of a chain combined with the quieter running of a belt-a compromise not without issues like tensioning, alignment, and timing issues.

Gear drives are more compact by comparison, rarely are run open due to wear. Are quite finicky as to alignment. Adequately lubricated and properly aligned, gear sets are relatively long lasting and suffer less power loss than either of the above. Gears are also positive drive nearly immune to slippage. Gear sets are more expensive to make and can be prohibitively expensive for low numbers of units. The solution in industry has been to make a few units and ratios and then mix and match, or add an external speed change - look at truck transmissions. 3 major mfrs each with a range of maybe 8 major units, paired with maybe one of 6 rearends from one of 3 makes. Very few heavy trucks (Mack might be the exception) are built totally from in-house assemblies. A KW, Pete, WesternStar,Sterling, and Volvo may have identical power trains.....
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Last edited by camdigger; 11-17-2020 at 11:22 AM.
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  #8  
Old 11-17-2020, 12:58 PM
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Quote:
Originally Posted by camdigger View Post
I had 3 motorcycles over the years. 2 chain drive and a shaft drive.

Chains are more flexible in alignment, cheaper to modify ratios, can be run open without undue wear. They are also nearly immune to slip. Chain drives tend to be bulky compared to gear drives. Chains tend to stretch and wear under load faster than gear sets. A 3 speed chain oil bath chain drive rated at 700 HP was 6' wide, 4' high, and 6' long. Quite bulky compared to the Allison automatic transmission that replaced it. Chain drives tend to be noisiest of the 3 drive types.

The positive drive of a chain or gear train lends itself to timing applications.

Belts have most of the above advantages, but are prone to slip if not tensioned enough. A belt drive may typically slip when a load is suddenly applied, or under high torque. Belts can be used as poorboy clutches, but only in low HP applications. Belts are limited in power transmission, but multiple belt drives are around transmitting several hundred HP. Those large belt drives are quite bulky. One mud pump drive I remember had a 16" diameter drive pulley and a 72" driven pulley. IIRC, there were 12 - 1 1/4" wide belts. The driver was a pair of 379 Cat engines. Naturally aspirated, they were rated at 550 HP each. Relatively recent clogged belts try to give the positive drive of a chain combined with the quieter running of a belt-a compromise not without issues like tensioning, alignment, and timing issues.

Gear drives are more compact by comparison, rarely are run open due to wear. Are quite finicky as to alignment. Adequately lubricated and properly aligned, gear sets are relatively long lasting and suffer less power loss than either of the above. Gears are also positive drive nearly immune to slippage. Gear sets are more expensive to make and can be prohibitively expensive for low numbers of units. The solution in industry has been to make a few units and ratios and then mix and match, or add an external speed change - look at truck transmissions. 3 major mfrs each with a range of maybe 8 major units, paired with maybe one of 6 rearends from one of 3 makes. Very few heavy trucks (Mack might be the exception) are built totally from in-house assemblies. A KW, Pete, WesternStar,Sterling, and Volvo may have identical power trains.....
Excellent explanation! Pretty much sums it all up in a few simple paragraphs...
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  #9  
Old 11-17-2020, 03:43 PM
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Originally Posted by LKeithR View Post
Excellent explanation! Pretty much sums it all up in a few simple paragraphs...
Well, he is an engineer
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You got freedom of speech, if you don't say too much.
Aaron Neville.

The virtue is always a cover for the sin. That's the key to understanding the modern left. Whatever they're accusing you of doing, they are doing themselves but more enthusiastically. And that's definitely the story of Justin Trudeau. Tucker Carlson
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  #10  
Old 11-17-2020, 10:54 PM
staybusy staybusy is offline
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Quote:
Originally Posted by camdigger View Post
I had 3 motorcycles over the years. 2 chain drive and a shaft drive.

Chains are more flexible in alignment, cheaper to modify ratios, can be run open without undue wear. They are also nearly immune to slip. Chain drives tend to be bulky compared to gear drives. Chains tend to stretch and wear under load faster than gear sets. A 3 speed chain oil bath chain drive rated at 700 HP was 6' wide, 4' high, and 6' long. Quite bulky compared to the Allison automatic transmission that replaced it. Chain drives tend to be noisiest of the 3 drive types.

The positive drive of a chain or gear train lends itself to timing applications.

Belts have most of the above advantages, but are prone to slip if not tensioned enough. A belt drive may typically slip when a load is suddenly applied, or under high torque. Belts can be used as poorboy clutches, but only in low HP applications. Belts are limited in power transmission, but multiple belt drives are around transmitting several hundred HP. Those large belt drives are quite bulky. One mud pump drive I remember had a 16" diameter drive pulley and a 72" driven pulley. IIRC, there were 12 - 1 1/4" wide belts. The driver was a pair of 379 Cat engines. Naturally aspirated, they were rated at 550 HP each. Relatively recent clogged belts try to give the positive drive of a chain combined with the quieter running of a belt-a compromise not without issues like tensioning, alignment, and timing issues.

Gear drives are more compact by comparison, rarely are run open due to wear. Are quite finicky as to alignment. Adequately lubricated and properly aligned, gear sets are relatively long lasting and suffer less power loss than either of the above. Gears are also positive drive nearly immune to slippage. Gear sets are more expensive to make and can be prohibitively expensive for low numbers of units. The solution in industry has been to make a few units and ratios and then mix and match, or add an external speed change - look at truck transmissions. 3 major mfrs each with a range of maybe 8 major units, paired with maybe one of 6 rearends from one of 3 makes. Very few heavy trucks (Mack might be the exception) are built totally from in-house assemblies. A KW, Pete, WesternStar,Sterling, and Volvo may have identical power trains.....
Thanks for sharing your knowledge. Very much appreciated!
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