CT trail 125......14/45 gearing... 48mph?

[Tim]

Anyone on here running a 45 tooth rear sprocket? 14/45. What's your cruising speed?
...
I'm a big guy. 280#
I might have to go to 13/45....
Be a stump puller wouldn't it ?

 

[ol mike]

Yes it would be a stump puller.

 

[SneakyDingo]

There's some calculators out there that can give you a rough estimate. I usually us 7200 RPM as the max RPM of the bike - it can go higher, I just don't usually do that.

14/39 with the OEM tires is around 57 mph at 7200 RPM (GPS, not indicated speed, indicated speed will be higher). I think we've already determined in multiple posts on the forum that you're using a downhill, drafting or a very strong tailwind to get that speed. Bike doesn't really have the horsepower without a BBK to get to that speed easily.

14/45 with the OEM tires at the same RPM is ~49 mph. It will definitely hit that speed. 1st will be very short, but the gap between 1st and 2nd will be a lot smaller.
13/45 with the OEM tires at the same RPM is ~45.4 mph.

At 280 lb I'd suggest buying to the JTF 273.13 13 tooth countersprocket first with the OEM chain and rear sprocket, and seeing how you feel about that. It's an easier install, cheaper, and will give you a good idea of how the gearing will make a difference. If you like that, then start with the JTR 269.42 combined with the OEM 14t countersprocket and make smaller adjustments to the rear sprocket tooth count - for example, I like the stock gearing, but I'd rather have a 40T rear sprocket. If you feel it still doesn't have enough OOMPH even with the 13T and you never see the top speed of the bike, you can try the JTR 269.45 rear sprocket + OEM countersprocket and see if that makes a difference. That being said, power is energy over time, and energy is defined as the displacement of mass by force over a distance. The bike is 9hp, there is no gearing that refutes the laws of physics of heavy rider + low horsepower = slow up hills. The main difference is you might have access to a different part of the rev range of the bike, which might help a tiny bit, or put you at a different speed on certain hills where the gear you'd normally be in forces you to either speed up or slow down.

 

[Tim]

There's some calculators out there that can give you a rough estimate. I usually us 7200 RPM as the max RPM of the bike - it can go higher, I just don't usually do that.

14/39 with the OEM tires is around 57 mph at 7200 RPM (GPS, not indicated speed, indicated speed will be higher). I think we've already determined in multiple posts on the forum that you're using a downhill, drafting or a very strong tailwind to get that speed. Bike doesn't really have the horsepower without a BBK to get to that speed easily.

14/45 with the OEM tires at the same RPM is ~49 mph. It will definitely hit that speed. 1st will be very short, but the gap between 1st and 2nd will be a lot smaller.
13/45 with the OEM tires at the same RPM is ~45.4 mph.

At 280 lb I'd suggest buying to the JTF 273.13 13 tooth countersprocket first with the OEM chain and rear sprocket, and seeing how you feel about that. It's an easier install, cheaper, and will give you a good idea of how the gearing will make a difference. If you like that, then start with the JTR 269.42 combined with the OEM 14t countersprocket and make smaller adjustments to the rear sprocket tooth count - for example, I like the stock gearing, but I'd rather have a 40T rear sprocket. If you feel it still doesn't have enough OOMPH even with the 13T and you never see the top speed of the bike, you can try the JTR 269.45 rear sprocket + OEM countersprocket and see if that makes a difference. That being said, power is energy over time, and energy is defined as the displacement of mass by force over a distance. The bike is 9hp, there is no gearing that refutes the laws of physics of heavy rider + low horsepower = slow up hills. The main difference is you might have access to a different part of the rev range of the bike, which might help a tiny bit, or put you at a different speed on certain hills where the gear you'd normally be in forces you to either speed up or slow down.

Thanks, for your response.
I just now went to the mail box.. the jtr-269-45 sprocket was in it.
I'll put it aside, and order up a 13tooth.. we'll try that 1st..
Thank you.

 

[TRF90]

I went with the 13 tooth several months ago. Might have lost 2 mph on top, but the bike is better at maintaining road speed on hills and into a light wind. I think you'll like it. My speedo is now 4 mph optimistic at an indicated 50 mph.

 

[Tim]

I went with the 13 tooth several months ago. Might have lost 2 mph on top, but the bike is better at maintaining road speed on hills and into a light wind. I think you'll like it. My speedo is now 4 mph optimistic at an indicated 50 mph.

I'm going to try the 13T .. it just came in the mail.
Nine dollar and shipping. Not bad.
For comparison sake..
My little Honda Ruckus.. top speed on my roads around here , is 40mph.
It's only a 50cc....
And I'm happy with it.
Bone stock.. I did add a windshield.
So ? Yeah ? Thank you Sneaky Dingo..
Your post sure did help
This coming summer.. I'm very much looking forward to exploring my gearing options..
I'll ride it stock for awhile, then try the 13T.. after that I'll put the 14T back on and the 45T rear... Ride it.
And then go with the 13/45 combo and see how I like it. 40-45 mph ..will probably be okay for me.
Yes I'll put on knobby tires..
Golly?? Just thinking about the 13/45 ?
She'll climb anything.. I'd say.
Thanks