Notices
General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

Drivetrain Math

Old 07-21-20, 08:09 AM
  #1  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Drivetrain Math

If you have a cheap drivetrain an expensive drivetrain with identical gear ratios int he crank and cassette, strictly speaking about power output of the drivetrain only, is there a difference?

I ride for the workout and not concerned with speed but my ego does get deflated when I am passed by someone. Mostly on hills and I upgraded my drivetrain to 50/34 11-28. I get passed a lot on slight inclines. My entire drivetrain is like $100, and my bike is an OLD Mangusta 5000 (made by Mongoose back in the day).

I know their bikes are $3K-$6K passing me but how much better can they be? Although I am in great shape, I am certain these people are just in better "cycling shape" and just curious how much modern bikes contribute to speed aside from the drivetrain.
paulriccio is offline  
Old 07-21-20, 08:50 AM
  #2  
AlmostTrick
Tortoise Wins by a Hare!
 
AlmostTrick's Avatar
 
Join Date: Feb 2006
Location: Looney Tunes, IL
Posts: 7,043

Bikes: Wabi Special FG, Raleigh Roper, Nashbar AL-1, Miyata One Hundred, '70 Schwinn Lemonator and More!!

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked 567 Times in 316 Posts
Originally Posted by paulriccio View Post
If you have a cheap drivetrain an expensive drivetrain with identical gear ratios int he crank and cassette, strictly speaking about power output of the drivetrain only, is there a difference?
There may be a tiny difference. But it would be so small as to not be noticeable. You'll still get passed! A higher end DT may be smoother/quieter and shift better though.

I ride for the workout and not concerned with speed but my ego does get deflated when I am passed by someone. Mostly on hills and I upgraded my drivetrain to 50/34 11-28. I get passed a lot on slight inclines. My entire drivetrain is like $100, and my bike is an OLD Mangusta 5000 (made by Mongoose back in the day).

I know their bikes are $3K-$6K passing me but how much better can they be? Although I am in great shape, I am certain these people are just in better "cycling shape" and just curious how much modern bikes contribute to speed aside from the drivetrain.
Only one way to find out... bust out the wallet!
AlmostTrick is offline  
Old 07-21-20, 08:54 AM
  #3  
Trakhak
Senior Member
 
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 2,137
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 579 Post(s)
Liked 213 Times in 149 Posts
I sold Mongoose bikes, including their road and off-road bike, in a bike shop in the 1990s, but I don't remember the Mangusta 5000. Just looked it up; nice bike.

Many riders go all out to pass people and then turn off onto another road and poke along at a snail's pace while gasping for breath.
Trakhak is offline  
Likes For Trakhak:
Old 07-21-20, 09:11 AM
  #4  
GrainBrain
Senior Member
 
GrainBrain's Avatar
 
Join Date: Aug 2017
Location: Central Io-way
Posts: 1,573

Bikes: LeMond Zurich, Giant Talon 29er

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 867 Post(s)
Liked 172 Times in 125 Posts
I still have PRs set on a mid 80's, lower end steel Panasonic thanks to its straight gauge 4130 tube set. Silly stiff with over inflated 1-1/4" tires at 100psi. 6 speed rear. Hill climbing beast.
GrainBrain is online now  
Old 07-21-20, 09:12 AM
  #5  
subgrade
Senior Member
 
Join Date: Apr 2018
Location: Rīga, Latvia
Posts: 733

Bikes: Focus Crater Lake

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 324 Post(s)
Liked 253 Times in 150 Posts
I don't think there is much difference strictly in efficiency between lower and higher end drivetrain components (probably there is some, but I'm sure it's negligible); it's more about, weight, durability and smoothness of shifting. Well maintained (clean and properly lubed) vs neglected drivetrain make more difference.

That said, riding up inclines it's mostly about power to weight ratio, so either those passing you are putting out more power, weigh less (together with the bike), or both.
subgrade is offline  
Old 07-21-20, 09:13 AM
  #6  
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 29,935

Bikes: Catrike 559 I own some others but they don't get ridden very much.

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1450 Post(s)
Liked 357 Times in 219 Posts
It's the motor.

If you put a Ferrari transmission into a Fiat 500 and made no other changes do you think it would go 150 MPH?
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
Retro Grouch is offline  
Old 07-21-20, 09:23 AM
  #7  
Pop N Wood
Senior Member
 
Join Date: Jun 2020
Location: Maryland
Posts: 505

Bikes: 1982 Bianchi Sport SX, Rayleigh Tamland 1, Rans V-Rex recumbent, Fuji MTB, 80's Cannondale MTB with BBSHD ebike motor, 70's vintage Schwinn Continental and Suburban

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 238 Post(s)
Liked 172 Times in 114 Posts
Originally Posted by Retro Grouch View Post
It's the motor.

If you put a Ferrari transmission into a Fiat 500 and made no other changes do you think it would go 150 MPH without breaking down?
Sorry, couldn't resist. A buddy had a X 1/9 back in the day and that thing went through transmissions faster than tires.

As the great racer said "don't buy upgrades, ride up grades". Agree with the others there may be slightly less driveline loss but not as much as say skipping the mid ride burrito.

Some guys on here argue the proper chain lube will turn you into Lance himself. Over the course of a ride it may make a cumulative difference in total energy spent, but going uphills there are bigger things at play.

Last edited by Pop N Wood; 07-23-20 at 04:33 AM.
Pop N Wood is online now  
Old 07-21-20, 09:26 AM
  #8  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,284 Times in 801 Posts
You said Math..

Ratios is the math.. chain ring # of T turns hub cog T in a ratio .. like say 2:1 pedals turn once wheel turns 2x.
if crank and hub cog is the same size then its a 1:1 gear , then the other factor is wheel diameter..


then there is air resistance .. there is a formula for that.

$$ spent per MPH is not applicable unless its not human powered ..







...

Last edited by fietsbob; 07-21-20 at 09:30 AM.
fietsbob is offline  
Old 07-21-20, 09:57 AM
  #9  
Litespud
Senior Member
 
Join Date: Oct 2017
Location: Chapel Hill NC
Posts: 928

Bikes: 2000 Litespeed Vortex Chorus 10, 1995 DeBernardi Cromor S/S, Nashbar 3sp commuter

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 356 Post(s)
Liked 321 Times in 181 Posts
Any number of reasons for why someone passes you - too many factors to address, really - power, weight (rider and bike), skill/technique, aero etc etc. All these things being equal, the only things that rob power are tire friction (rolling resistance), wheel bearing friction, BB friction, chain friction and jockey wheel bearing friction. I imagine that, short of going with ceramic bearings or something equally high-zoot, well-maintained, well-adjusted bearings, either loose ball or cartridge, are going to be close enough to make little difference. Tire friction? - lots of info out there about the benefits of wider, softer (up to a point) tires on rolling resistance. Chain? maintenance and chain line - a well-maintained, straight chain is a more efficient chain. I would say that a well maintained, well adjusted cheaper drivetrain will be essentially as efficient as a similarly maintained and adjusted expensive drivetrain - the expensive one will likely shift better and be lighter, but more efficient? Not so you'd notice.
Litespud is offline  
Likes For Litespud:
Old 07-21-20, 10:36 AM
  #10  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 2,258

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 500 Post(s)
Liked 239 Times in 172 Posts
The question I gave is if you are getting passed while in the 34-28 gear. If yes, then you might want to go with a lower gear cassette like a 34t.

There are all sorts of reasons why you are getting passed, but they all point to not being as strong a rider. So, give yourself a lower gear and maybe you can keep your cadence up a little higher and go a little faster.

This will allow you to spend some money, (new cassette, chain, rear derailleur) not just duplicate what you have that will make little to no difference.

John
70sSanO is offline  
Old 07-21-20, 10:40 AM
  #11  
Phil_gretz
Journeyman Bike Commuter
 
Phil_gretz's Avatar
 
Join Date: Aug 2009
Location: Alexandria, VA
Posts: 5,913

Bikes: '71 Jeunet 640, '74 Fuji Special Road Racer, '79 Peugeot PXN10LE, '88 Fuji Saratoga, '13 Motobecane Fantom29 HT, '16 Motobecane Turino Pro Disc, '16 Motobecane Gran Premio Elite, '18 Velobuild VB-R-022

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 983 Post(s)
Liked 638 Times in 362 Posts
You knew the answer before you asked the question. It's about watts produced, watts saved, and watts/kg when climbing. Watts produced is entirely on you, your bike fit, your nutrition, your physical and cardiovascular capacity, your recovery abilities, your general health and that day's particular reserves, etc. That's the watts produced side.

So, you're asking about watts saved. Yes, a perfectly clean and tuned, well lubricated top-shelf drivetrain can safe you a few watts, like a few.

Several posters mentioned smoother shifting, which is a real thing. One reason I prefer certain brands of crankset is that the shifting is noticeably better on the upshift. This equates the tiniest amount of energy saved. It is large enough to be measured, but not so large as to make a bit of difference to you or me.

On even a slight incline, gravity (does) and wind resistance (can) work against you. Lose as much weight from yourself as you can and still perform at your best. Have noticed that climbing while carrying a loaded backpack is harder than climbing when just riding around without the extra stuff?
Phil_gretz is offline  
Old 07-21-20, 10:52 AM
  #12  
Phil_gretz
Journeyman Bike Commuter
 
Phil_gretz's Avatar
 
Join Date: Aug 2009
Location: Alexandria, VA
Posts: 5,913

Bikes: '71 Jeunet 640, '74 Fuji Special Road Racer, '79 Peugeot PXN10LE, '88 Fuji Saratoga, '13 Motobecane Fantom29 HT, '16 Motobecane Turino Pro Disc, '16 Motobecane Gran Premio Elite, '18 Velobuild VB-R-022

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 983 Post(s)
Liked 638 Times in 362 Posts
I was thinking. Has the OP confirmed that his hubs are perfectly adjusted so as not to rob him of precious watts? Tires optimally chosen and at the best possible inflation? These things matter, too.
Phil_gretz is offline  
Old 07-21-20, 12:09 PM
  #13  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 6,822

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400

Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 1303 Post(s)
Liked 712 Times in 489 Posts
Their bike is 20 pounds lighter
dedhed is online now  
Old 07-21-20, 12:09 PM
  #14  
BobbyG
Senior Member
 
BobbyG's Avatar
 
Join Date: Jan 2009
Location: Colorado Springs, CO
Posts: 5,011

Bikes: 2015 Charge Plug, 1997 Nishiki Blazer, 1984 Nishiki International

Mentioned: 52 Post(s)
Tagged: 0 Thread(s)
Quoted: 1077 Post(s)
Liked 689 Times in 339 Posts
I live in Colorado Springs, home to one of the Olympic Training Centers. so I get passed a lot , but not by "casual" cyclists. And not in the snow...probably because so few people ride in snow and ice. I ride with studded snow tires in the winter and passing cars going up an icy hill is supremely satisfying.
BobbyG is offline  
Old 07-22-20, 09:12 PM
  #15  
veganbikes
Clark W. Griswold
 
Join Date: Mar 2014
Location: ,location, location
Posts: 6,292

Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), Cilo Road Frame, Proteus frame, Ti 26 MTB

Mentioned: 31 Post(s)
Tagged: 0 Thread(s)
Quoted: 1538 Post(s)
Liked 365 Times in 261 Posts
Originally Posted by Retro Grouch View Post
It's the motor.

If you put a Ferrari transmission into a Fiat 500 and made no other changes do you think it would go 150 MPH?
You clearly haven't pushed a Fiat 500 with a Ferrari transmission off a cliff!
veganbikes is offline  
Old 07-22-20, 10:29 PM
  #16  
ofajen
Cheerfully low end
 
Join Date: Jun 2020
Posts: 357
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked 156 Times in 97 Posts
Originally Posted by veganbikes View Post
You clearly haven't pushed a Fiat 500 with a Ferrari transmission off a cliff!
My impression from the guys at the local dealership with a Fiat franchise is that they would be fine with extensive testing to determine the terminal velocity of a Fiat 500 when dropped from altitude. 😊

Otto
ofajen is offline  
Likes For ofajen:
Old 07-22-20, 10:34 PM
  #17  
veganbikes
Clark W. Griswold
 
Join Date: Mar 2014
Location: ,location, location
Posts: 6,292

Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), Cilo Road Frame, Proteus frame, Ti 26 MTB

Mentioned: 31 Post(s)
Tagged: 0 Thread(s)
Quoted: 1538 Post(s)
Liked 365 Times in 261 Posts
Originally Posted by ofajen View Post
My impression from the guys at the local dealership with a Fiat franchise is that they would be fine with extensive testing to determine the terminal velocity of a Fiat 500 when dropped from altitude. 😊

Otto
veganbikes is offline  
Old 07-23-20, 02:13 AM
  #18  
subgrade
Senior Member
 
Join Date: Apr 2018
Location: Rīga, Latvia
Posts: 733

Bikes: Focus Crater Lake

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 324 Post(s)
Liked 253 Times in 150 Posts
Originally Posted by Retro Grouch View Post
It's the motor.

If you put a Ferrari transmission into a Fiat 500 and made no other changes do you think it would go 150 MPH?
On the other hand, if you put a Ferrari engine into a Fiat 500 and made no other changes it still would not go 150 mph, since it would kill the transmission pretty much instantly as soon you'd really step on the pedal.
subgrade is offline  
Old 07-23-20, 11:19 AM
  #19  
bruce19
Senior Member
 
bruce19's Avatar
 
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 7,334

Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 1232 Post(s)
Liked 575 Times in 346 Posts
Originally Posted by GrainBrain View Post
I still have PRs set on a mid 80's, lower end steel Panasonic thanks to its straight gauge 4130 tube set. Silly stiff with over inflated 1-1/4" tires at 100psi. 6 speed rear. Hill climbing beast.
A Panasonic DX 2000 was my first proper road bike.
bruce19 is offline  
Old 07-26-20, 02:58 PM
  #20  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Thanks for the reply. After the new components, it is so much better. The hills were killing me. It has an old flywheel and I may see if I can upgrade to a 11-32 or 34 and do a cassette. Would take some research.

While I got you. I am in the Northeast USA and the roads SUCK. I have 700 x 23 and was looking for a bigger tire and lower pressure. If it fit I was looking at 32 and kind of make it a gravel type bike. I occasionally have some gravel roads.
paulriccio is offline  
Old 07-26-20, 03:00 PM
  #21  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
I figured as much. I have some muscle mass and I know that takes oxygen. That being said, I think they have better cardio, stronger legs, and lighter everything. Fascinating though.
paulriccio is offline  
Old 07-26-20, 03:03 PM
  #22  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Word
paulriccio is offline  
Old 07-26-20, 03:04 PM
  #23  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Informative, thanks.
paulriccio is offline  
Old 07-26-20, 03:06 PM
  #24  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Thanks. I have a large cage derailer on now but have to look up the specs. I would have to buy new rims (I think) since my bike has a flywheel and not a cassette if I upgrade to the current century.
paulriccio is offline  
Old 07-26-20, 03:11 PM
  #25  
paulriccio
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 44
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
I hear you. I really thought it made VERY little difference but I am by no means an expert. It's a hell of a thing the different types of fitness there are. Some wiry frames can have insane cardio AND stronger legs over time. I was just curious about the math, I do it for the workout, not speed.

My shifters are on the frame and i have to read down. It blows. I will have to do research to even see if I can convert that. In due time.

Thanks for the reply.
paulriccio is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright İ 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.