Posted by Broderick Crawford on April 17, 2007, 9:27 am
I'm looking at changing my rear sprocket to increase my road speed and
decrease engine rev at highway speeds. I currently have a 428 chain with
a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
change can I expect with 10 less teeth on the rear? Will there be a
noticeable change or should I go to a 30 tooth sprocket? Anybody tried this?
--
Bcrawford
Posted by Mark Olson on April 17, 2007, 9:37 am
Broderick Crawford wrote:
> I'm looking at changing my rear sprocket to increase my road speed and
> decrease engine rev at highway speeds. I currently have a 428 chain with
> a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
> change can I expect with 10 less teeth on the rear? Will there be a
> noticeable change or should I go to a 30 tooth sprocket? Anybody tried this?
You're probably not going to improve the TW200's "road speed" much by
fitting a different sprocket.
You don't also happen to own a Honda 350 or 360, do you?
If you *must* experiment with sprockets, change by a smaller number of
teeth, going from a 50 tooth to a 40 tooth rear will make your top
gear useless. Don't even think about putting a 30 tooth rear on there.
--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Posted by Broderick Crawford on April 17, 2007, 9:59 am
Mark Olson wrote:
> Broderick Crawford wrote:
>> I'm looking at changing my rear sprocket to increase my road speed and
>> decrease engine rev at highway speeds. I currently have a 428 chain with
>> a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
>> change can I expect with 10 less teeth on the rear? Will there be a
>> noticeable change or should I go to a 30 tooth sprocket? Anybody tried
>> this?
>
> You're probably not going to improve the TW200's "road speed" much by
> fitting a different sprocket.
>
> You don't also happen to own a Honda 350 or 360, do you?
>
> If you *must* experiment with sprockets, change by a smaller number of
> teeth, going from a 50 tooth to a 40 tooth rear will make your top
> gear useless. Don't even think about putting a 30 tooth rear on there.
>
Well, they sell a 49, 48, 47, 46 etc sprocket. Does one tooth make that
much of a difference? I'll search the web and try to find out how much
this changes the gearing ratio.
--
Bcrawford
Posted by Mark Olson on April 17, 2007, 10:18 am
Broderick Crawford wrote:
> Mark Olson wrote:
>
>>Broderick Crawford wrote:
>>
>>>I'm looking at changing my rear sprocket to increase my road speed and
>>>decrease engine rev at highway speeds. I currently have a 428 chain with
>>>a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
>>>change can I expect with 10 less teeth on the rear? Will there be a
>>>noticeable change or should I go to a 30 tooth sprocket? Anybody tried
>>>this?
>>
>>You're probably not going to improve the TW200's "road speed" much by
>>fitting a different sprocket.
>>
>>You don't also happen to own a Honda 350 or 360, do you?
>>
>>If you *must* experiment with sprockets, change by a smaller number of
>>teeth, going from a 50 tooth to a 40 tooth rear will make your top
>>gear useless. Don't even think about putting a 30 tooth rear on there.
>>
>
> Well, they sell a 49, 48, 47, 46 etc sprocket. Does one tooth make that
> much of a difference? I'll search the web and try to find out how much
> this changes the gearing ratio.
*Boggle*
For the same road speed, your RPMs will be proportionally lower by
the new tooth count divided by the original tooth count.
So, if you are running 5000 rpm at 60 mph with a 50 tooth rear
sprocket, the new RPMs at 60 mph with a 48 tooth sprocket will be:
5000 RPM * 48T / 50T = 4800 RPM
For constant RPMs, your road speed will be speed * (50/tooth count):
60 mph * 50T / 48T = 62.5 mph
But remember, you have a 200cc single there, and it's not an unlimited
power source, as you decrease the RPMs you decrease the available
power. The folks who picked the gear ratios for that bike knew what
they were doing.
--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Posted by Broderick Crawford on April 17, 2007, 10:46 am
Mark Olson wrote:
> Broderick Crawford wrote:
>> Mark Olson wrote:
>>
>>> Broderick Crawford wrote:
>>>
>>>> I'm looking at changing my rear sprocket to increase my road speed and
>>>> decrease engine rev at highway speeds. I currently have a 428 chain
>>>> with
>>>> a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
>>>> change can I expect with 10 less teeth on the rear? Will there be a
>>>> noticeable change or should I go to a 30 tooth sprocket? Anybody tried
>>>> this?
>>>
>>> You're probably not going to improve the TW200's "road speed" much by
>>> fitting a different sprocket.
>>>
>>> You don't also happen to own a Honda 350 or 360, do you?
>>>
>>> If you *must* experiment with sprockets, change by a smaller number of
>>> teeth, going from a 50 tooth to a 40 tooth rear will make your top
>>> gear useless. Don't even think about putting a 30 tooth rear on there.
>>>
>>
>> Well, they sell a 49, 48, 47, 46 etc sprocket. Does one tooth make that
>> much of a difference? I'll search the web and try to find out how much
>> this changes the gearing ratio.
>
> *Boggle*
>
> For the same road speed, your RPMs will be proportionally lower by
> the new tooth count divided by the original tooth count.
>
> So, if you are running 5000 rpm at 60 mph with a 50 tooth rear
> sprocket, the new RPMs at 60 mph with a 48 tooth sprocket will be:
>
> 5000 RPM * 48T / 50T = 4800 RPM
>
> For constant RPMs, your road speed will be speed * (50/tooth count):
>
> 60 mph * 50T / 48T = 62.5 mph
>
> But remember, you have a 200cc single there, and it's not an unlimited
> power source, as you decrease the RPMs you decrease the available
> power. The folks who picked the gear ratios for that bike knew what
> they were doing.
>
Well in my opinion the bike should have had one lower gear for off road
and one higher gear for the highway. Or else a 2 speed rear wheel.
So now I have to get a larger sprocket for off road and a smaller one
for highway. I mean, it's ok the way it is but it could have been just a
little better.
I see a 14 tooth drive with a 50 tooth driven gives a 3.57 to 1 ratio so
1000 rpms is reduced to 280 rpms.
A 40 is 2.85 to 1 or 350 rpms, a 30 tooth is 2.1 to 1 or 460 rpms.
A 49 tooth drops to 3.5 and 280.5 rpms.
--
--
Bcrawford
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> decrease engine rev at highway speeds. I currently have a 428 chain with
> a 50 tooth sprocket. I am looking at a 428/40 sprocket. What speed
> change can I expect with 10 less teeth on the rear? Will there be a
> noticeable change or should I go to a 30 tooth sprocket? Anybody tried this?