how much does tire size affect the final drive?

Oaklandish · July 18th, 2011, 10:17 PM

would increasing the front tire size equal less rpm at higher speeds? (like gearing)

Alex · July 18th, 2011, 10:21 PM

The size of the front tire has nothing to do with rpms of the engine, or gearing, is that what you meant?

Snake · July 18th, 2011, 10:41 PM

The front tire hub has a gear and cable that runns the speedometer and trip meter.

Oaklandish · July 18th, 2011, 10:50 PM

Quote:

Originally Posted by Alex

The size of the front tire has nothing to do with rpms of the engine, or gearing, is that what you meant?

I know gearing is what mainly determines rpm but i thought tire size influences it as well. isnt that why drag race cars have off set tires, for faster acceleration?

Alex · July 18th, 2011, 10:55 PM

I'm still not sure I follow. Drag cars have tiny front wheels because they don't need anything larger. The thinner and lighter they are, the less drag they have, so at very high speeds, the car can go that slight bit faster than it would with wider or heavier wheels. They still have nothing to do with the drive of the car (or the bike), and have nothing to do with the gearing, or the drivetrain at all, right?

Oaklandish · July 18th, 2011, 10:58 PM

Quote:

Originally Posted by Alex

I'm still not sure I follow. Drag cars have tiny front wheels because they don't need anything larger. The thinner and lighter they are, the less drag they have, so at very high speeds, the car can go that slight bit faster than it would with wider or heavier wheels. They still have nothing to do with the drive of the car (or the bike), and have nothing to do with the gearing, or the drivetrain at all, right?

i think you're following... my idea was this, wouldn't it take more rpm to push a bigger wheel? i might be wrong and its the same not matter what

Alex · July 18th, 2011, 11:07 PM

No, the rpm's of the engine have nothing to do with the front wheel. If the rear wheel was taller, the rpm's of the wheel (and therefore the engine) would be slightly lower in proportion to the larger size of the wheel. It would be the same as going with slightly taller sprockets.

Snake · July 18th, 2011, 11:49 PM

Felipe the Ant · July 19th, 2011, 01:02 AM

The only thing that affects gearing other than gears/sprockets is the rear wheel diameter. The front will only affect the speedo reading.

CThunder-blue · July 19th, 2011, 07:59 AM

Quote:

Originally Posted by Oaklandish

I know gearing is what mainly determines rpm but i thought tire size influences it as well. isnt that why drag race cars have off set tires, for faster acceleration?

Yes, smaller diameter wheels will accelerate faster, but will not affect the Final Drive. Final Drive is speed vs. RPM. Acceleration is Time vs. speed.

So to answer your first post, a smaller tire circumference may allow you to accelerate slightly faster (probably not even noticeable), but won't do much for top speed. It does affect your speedometer reading in cars and bikes with electronic speedos, but not on our bikes since the speedo reads off the hub and is mechanical.

blink · July 19th, 2011, 02:51 PM

Quote:

Originally Posted by drsketch

bigger front tire = less miles on speedometer, and keep in mind changing your bike may produce an effect that you do not want.

Your still travelling the same distance?

Suave · July 19th, 2011, 05:52 PM

tire size will not significantly effect your rpms at all on the subject of gearing, but it will require an increase of power to turn them because the added weight and drag. I know what you are asking because I asked the same thing in my first Auto-class in high school lol There was a lot of pain and pictures and yelling before it was explained to me in a way I understood

; but I assure you, alex is right, tire size will not 1. effect your rpms 2. effect your speed 3. change your acceleration/top speed on a gearing level (it is only top speed) will if you get a larger size.

The reason drag cars have smaller fronts is like Alex said, less drag = faster accel; and like Thunder said, it will only change your acceleration very slightly, probably only hundreths and maybe tenths of a second (because sometimes that makes the difference on the strip)

ducducgooseit · July 20th, 2011, 08:42 AM

Silly readers. ANY change in the circumference of a tire will change the wheels RPM given a steady velocity. The question that should be asked is, "At what size will the change in rpms be noticeable?" THAT question should be answered thusly, "At no size that will make the vehicle behave the same will a tire change noticeably affect the wheels RPM."

CynicalC · July 20th, 2011, 08:51 AM

Quote:

Originally Posted by ducducgooseit

Silly readers. ANY change in the circumference of a tire will change the wheels RPM given a steady velocity. The question that should be asked is, "At what size will the change in rpms be noticeable?" THAT question should be answered thusly, "At no size that will make the vehicle behave the same will a tire change noticeably affect the wheels RPM."

Only the diameter of the DRIVE tire will affect the final drive. The front tire is just an idler. It can be a roller blade wheel and the bike will still go the same speed, regardless of the rpm of the front tire. The only thing that may change with a different size front tire is the REPORTED speed, as the speedometer reading is taken off the front wheel.

Some of you need to sit through 6th grade science again. Simple machine #1 - the wheel.

The original question is vague, but alex is correct. Changing the size of the front tire will have no effect on the speed or gearing of the bike mechanically. Only the reported speed as the front wheel will be spinning at a different rpm.

CynicalC · July 20th, 2011, 09:01 AM

Quote:

Originally Posted by CThunder-blue

A smaller tire circumference may allow you to accelerate slightly faster

This is incorrect, as we're talking about the front tire.

Quote:

Originally Posted by CThunder-blue

It does affect your speedometer reading, but not on our bikes since the speedo reads off the hub and is mechanical.

This is also incorrect, for the reason you stated. A smaller front tire would cause the front wheel (hub and all) to be turning at a higher rpm. It will effect the speedometer reading.

CThunder-blue · July 20th, 2011, 09:09 AM

Quote:

Originally Posted by CynicalC

This is incorrect, as we're talking about the front tire.

This is also incorrect, for the reason you stated. A smaller front tire would cause the front wheel (hub and all) to be turning at a higher rpm. It will effect the speedometer reading.

In regards to the our 250, we already experience up to a 10% discrepancy in speed. A slight change in tire size will not make a noticeable difference in the way the mechanical speedo reads.

blink · July 20th, 2011, 09:10 AM

Quote:

Originally Posted by ducducgooseit

Silly readers. ANY change in the circumference of a tire will change the wheels RPM given a steady velocity. The question that should be asked is, "At what size will the change in rpms be noticeable?" THAT question should be answered thusly, "At no size that will make the vehicle behave the same will a tire change noticeably affect the wheels RPM."

We are talking about actually RPM which is engine speed. Not tires, so in this case your argument is true in a non relative way

July 18th, 2011, 10:21 PM	#2
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	The size of the front tire has nothing to do with rpms of the engine, or gearing, is that what you meant? __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

July 18th, 2011, 10:55 PM	#5
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	I'm still not sure I follow. Drag cars have tiny front wheels because they don't need anything larger. The thinner and lighter they are, the less drag they have, so at very high speeds, the car can go that slight bit faster than it would with wider or heavier wheels. They still have nothing to do with the drive of the car (or the bike), and have nothing to do with the gearing, or the drivetrain at all, right? __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

July 18th, 2011, 11:07 PM	#7
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	No, the rpm's of the engine have nothing to do with the front wheel. If the rear wheel was taller, the rpm's of the wheel (and therefore the engine) would be slightly lower in proportion to the larger size of the wheel. It would be the same as going with slightly taller sprockets. __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

July 19th, 2011, 05:52 PM	#12
Suave ninjette.org member Name: Mark Location: Maryville, Tennessee Join Date: Jun 2011 Motorcycle(s): 2008 Ninja 250r Posts: 94	tire size will not significantly effect your rpms at all on the subject of gearing, but it will require an increase of power to turn them because the added weight and drag. I know what you are asking because I asked the same thing in my first Auto-class in high school lol There was a lot of pain and pictures and yelling before it was explained to me in a way I understood ; but I assure you, alex is right, tire size will not 1. effect your rpms 2. effect your speed 3. change your acceleration/top speed on a gearing level (it is only top speed) will if you get a larger size. The reason drag cars have smaller fronts is like Alex said, less drag = faster accel; and like Thunder said, it will only change your acceleration very slightly, probably only hundreths and maybe tenths of a second (because sometimes that makes the difference on the strip) __________________________________________________ "Hey man, I'm not tryin' to start nothin'. But... i wouldn't take that"

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July 18th, 2011, 10:17 PM	#1
Oaklandish ninjette.org member Name: Rowan Location: oakland, kawifornia Join Date: Jun 2011 Motorcycle(s): 2002 ninja 250 Posts: 96	how much does tire size affect the final drive? would increasing the front tire size equal less rpm at higher speeds? (like gearing)

July 18th, 2011, 10:41 PM	#3
Snake ninjette.org certified postwhore Name: Rick Location: Alexandria, Louisiana Join Date: Jan 2009 Motorcycle(s): 05 Blue Ninja 250 Posts: Too much. MOTY - 2017, MOTM - Jan '19, Oct '16, May '14	The front tire hub has a gear and cable that runns the speedometer and trip meter.

July 18th, 2011, 11:49 PM	#8
Snake ninjette.org certified postwhore Name: Rick Location: Alexandria, Louisiana Join Date: Jan 2009 Motorcycle(s): 05 Blue Ninja 250 Posts: Too much. MOTY - 2017, MOTM - Jan '19, Oct '16, May '14

July 19th, 2011, 01:02 AM	#9
Felipe the Ant ninjette.org sage Name: . Location: . Join Date: May 2011 Motorcycle(s): 2011 Ninja 250R SE GREEN! Posts: 562	The only thing that affects gearing other than gears/sprockets is the rear wheel diameter. The front will only affect the speedo reading.

July 20th, 2011, 08:42 AM	#13
ducducgooseit Name: ... Location: ... Join Date: May 2009 Motorcycle(s): ... Posts: 999	Silly readers. ANY change in the circumference of a tire will change the wheels RPM given a steady velocity. The question that should be asked is, "At what size will the change in rpms be noticeable?" THAT question should be answered thusly, "At no size that will make the vehicle behave the same will a tire change noticeably affect the wheels RPM."