Sprocket combination for higher speed or fuel economy

[NicksCT125]

First time posting here, so hello everyone!

I use my bike mostly for commuting to my job which is about a 26 mile ride each way, most of which is on 60mph back roads (in the UK).

I love the bike, but I’m finding I’m at 100% throttle for more and more of my commute as I get used to the bike and get to know the corners on my route extremely well.

I’ve had a but of a look for info on sprockets on other threads but it seems like most people are gearing down for off road use rather than up for street use. I’m also not great at finding specific info on forums like these.

So my question is, does anyone have any suggestions for front and back sprocket sizes to either increase the top speed a little or make it a little more economical/comfortable sitting at 45/50mph or more.

Thanks in advance for any help!

 

[dmonkey]

At 100% throttle you are just past peak power. When on long stretches of road riding I will often back off just slightly from there and find it to be a more comfortable spot, though you can run the engine at wide open throttle all day and it won't be a problem. The CT has a lower redline/rev-limiter than the Grom/MSX for example, which can also be run at WOT all day long. Going to a 15T front sprocket will lug the engine more and may not return any increase in top speed or fuel economy, though you can try. The CT125 is geared and tuned differently than the Super Cub and other Honda mini motos where it favors mid range torque at the expense of top speed and peak hp. If you really want to target fuel economy, finding a slower route and riding slow is likely to yield the best fuel economy. I know some people don't like the sound of the bike at high RPM, but again, it's okay to run it like that, just check the oil level more frequently and consider hearing protection if you don't like how it sounds.

 

[NicksCT125]

At 100% throttle you are just past peak power. When on long stretches of road riding I will often back off just slightly from there and find it to be a more comfortable spot, though you can run the engine at wide open throttle all day and it won't be a problem. The CT has a lower redline/rev-limiter than the Grom/MSX for example, which can also be run at WOT all day long. Going to a 15T front sprocket will lug the engine more and may not return any increase in top speed or fuel economy, though you can try. The CT125 is geared and tuned differently than the Super Cub and other Honda mini motos where it favors mid range torque at the expense of top speed and peak hp. If you really want to target fuel economy, finding a slower route and riding slow is likely to yield the best fuel economy. I know some people don't like the sound of the bike at high RPM, but again, it's okay to run it like that, just check the oil level more frequently and consider hearing protection if you don't like how it sounds.

I’m already taking the slow route haha. My other option is the motorway but it’s not as nice and would probably take much longer as it’s a less direct route. The sound doesn’t bother me at all, I guess I’m really just looking for more speed haha. Maybe I’ll save for a bigger bike for my commute and orient the CT more towards trails and more relaxed rides.

In the meantime, I may give the 15T front a go, but do you know of anything else I can try to eek out a mph or 2?

 

[BergyPatty37]

The bike is what it is. Short of spending a few thousand dollars on big bore kits, exhaust, cams, etc you won't really get much improvement in terms of speed. If you do it with regearing you are going to have harder time getting up to speed and will be going slower up hills.

 

[Oldfatguy]

There was a very good test posted on regearing a Trail125. End result is that going to larger front sprocket did not help.

OFG

 

[NJChris]

I'm also very new here, but if you're just trying to eek out a couple of mph, maybe a windscreen will help. I just bought one (that hasn't arrived yet) that I got for comfort, but I'm interested to see if it gets me a mph or two in aerodynamics. Maybe I'm wrong, but someone else can correct me if so.

 

[BergyPatty37]

I didn't notice any difference with windscreen., but it is still nice to have.
Also don't go off the bike speedometer it is off even from factory, if you have a gps that is better way to judge true speed.

Really the best way to gain speed for most people is to lose weight. I can cruise comfortably around 50-52mph actual speed, even though i regeared to 13/42 but that is also because I weigh 165 lbs.

 

[babetta80]

I have been keeping an eye out for a cheap super cub ecu to see if it's plug and play and might yield a faster top speed

 

[dmonkey]

Unfortunately, at least for the JA55, the Super Cub ECM has been tested and doesn't work in the Trail.

Super Cub top speed on a Trail 125

I spend most of the time commuting and running errands on my ct125, and I've been thinking lately about what could be done to get the same top speed out of a ct125 as a grom or super Cub. Has anyone heard of swapping a super cub pgm fi unit into a ct125? Does anyone know if there are internal...

hondatrail125.com