Sprockets

[CT125 RIDER]

You've been a big help and I appreciate it a lot. I finally ordered the sprocket from the UK for $27 shipped with a delivery by March 1 (if customs doesn't hold it up a couple weeks like they've done to me in the past). I decided to just wait for the 41t rather than get the 15/44 more quickly. If I need lower gearing than the 13/39, I'll put the the 13 with the 41 and have 3.15!

Are you still running 14/ 41 on your bike? Is it a good happy medium? Where did you get it?

 

[Helowzrd]

Ok guys. I haven't been participating but intently reading. All of you guys have had good thoughts. I am interested what each of your results are with the sprocket changes. I am planning to do the TAT. Some Guy Rides did it with a stock bike and it couldn't make it over the alpine passes without being pushed. My concern with changing the sprockets is the higher RPMs. When I get to Oklahoma, Utah, Nevada, etc, it will be hot and I don't want overheating issues. Thanks.

 

[Migolito]

Drop a tooth in the front. I'm 220pounds plus gear, plus about 50 pounds of bags, camping equipment, etc. No issues at all. Last summer I did an 1100 mile adventure ride in up to 100+ weather and no overheating ussies. Ofcourse, you could always carry the larger front sprocket and change out.

 

[Helowzrd]

Drop a tooth in the front. I'm 220pounds plus gear, plus about 50 pounds of bags, camping equipment, etc. No issues at all. Last summer I did an 1100 mile adventure ride in up to 100+ weather and no overheating ussies. Ofcourse, you could always carry the larger front sprocket and change out.

Thanks for your thoughts. You and I are about the same. I'm 6'4" and 130 plus 30 pounds of baggage not including water or the extra gallon of gas I will be carrying. I was planning to switch to a 13T before the passes and didn't know if that would be enough so I was thinking to change the rear sprocket before setting off so when I switch to the 13T, I will have a better ratio. My fiance is going to. I will be in the doghouse if she has to push the cycle over a pass. :0.
I will do some testing before replacing the chain and I appreciate the insight.

 

[dmonkey]

My fiance is going to. I will be in the doghouse if she has to push the cycle over a pass. :0.

LOL. I am in Colorado and often have to doggie paddle the bike going up local 4x4 roads in the foothills. Pushing the bike has happened with mud, but for mountain passes you may find yourself in a situation where walking along side it and working the throttle is easier than being on it for short stretches of difficult terrain. Do not be intimidated by that, this is a really common technique for dealing with steep grades, big steps, and terrain consisting of large rocks which are common on the passes. You'll see people on everything from dirt bikes to giant BMW GS bikes doing it. Going to a bigger bike doesn't necessarily get you around having to do this, because when you're walking the bike it's usually because that's the safer option vs trying to ride it and risking a tip over that would break a leg and end in a helicopter ride. For the TAT, you and your fiance should expect those kinds of challenges, and be geared up and prepared for possibly dropping bikes a few times along the trip. It's best to acknowledge that's part of the adventure and you need to be okay with it rather than thinking you won't have to deal with those things and being disappointed when it does happen.

 

[SneakyDingo]

The other part is those big GS's, KTM's, all have much taller seat heights and no underbone frame. Typically around 35" for the ADV GS, KTM adventure in the modern versions is still 33.5" or so, the Trail Tractor 125 being only 31.5". Waddling up is much easier on that bike than walking up alongside due to that much lower seat height and low slung bodyweight. I think in terms of the SomeGuyRides videos, that made it possible for him to ride above his skill level at the Ophir pass area, and it definitely makes me feel more confident doing boneheaded sh*t. He also gave his thoughts at the end and seemed to think that the low top speed of Little Ugly Homefry on the interstate sections was a bigger problem overall.

I've given this a ton of thought, and I'm team -1T front, stock rear sprocket for the passes only. This is partly speaking to my mindset in the moment, but also the performance of the bike that Warro demonstrated. I don't do so well above +6500 ft change without acclimatization. Tired, grumpy and wanting to do the easier options that allow me more rest and recuperation will help me in that moment I think. Additionally, I'm also mindful that whatever I do, I'd probably want to undo it once I'm past the passes to get back to the stock gearing that's a pretty good sweet spot.

Keeping in mind that perspective, the front sprocket swap will be a strap to stop the rear wheel rotating, 4 bolts to remove covers, 2 bolts to remove the sprocket, some blue Loctite for good luck[1] and the rear axle nuts plus tensioning bolts on the rear to adjust the new chain tension. That doesn't sounds so bad. The rear sprocket swap is the exact same operation, except it also requires pulling the wheel off and reinserting it with finesse, rather than just loosening the bolts for chain slack adjustment. That sounds like tired me wouldn't want to do that. The actual sprocket swap looks pretty easy, it's 4 nuts and some gentle persuasion to free the sprocket.

Then I'm also mindful that whatever I'm doing, I'm probably doing it twice because fiancé with matching bike right? Unless they're doing their own wrenching, in which case you have the same discussions for mindset and fatigue, but for two different people.

It's best to acknowledge that's part of the adventure and you need to be okay with it rather than thinking you won't have to deal with those things and being disappointed when it does happen.

There's a saying with tandem bicycle riders that "tandems will get you where you're going faster and that it's especially true if you're referring to marriage or divorce". Speaking more generically from past experience, tis better in both the explicitly obvious but also the more subtle nuances to discover how such a hardship is endured as "fiancé" than as "wife".

[1] it's always lucky when bolts that are supposed to stay tight do actually stay tight

 

[SLO]

The other part is those big GS's, KTM's, all have much taller seat heights and no underbone frame. Typically around 35" for the ADV GS, KTM adventure in the modern versions is still 33.5" or so, the Trail Tractor 125 being only 31.5". Waddling up is much easier on that bike than walking up alongside due to that much lower seat height and low slung bodyweight. I think in terms of the SomeGuyRides videos, that made it possible for him to ride above his skill level at the Ophir pass area, and it definitely makes me feel more confident doing boneheaded sh*t. He also gave his thoughts at the end and seemed to think that the low top speed of Little Ugly Homefry on the interstate sections was a bigger problem overall.

I've given this a ton of thought, and I'm team -1T front, stock rear sprocket for the passes only. This is partly speaking to my mindset in the moment, but also the performance of the bike that Warro demonstrated. I don't do so well above +6500 ft change without acclimatization. Tired, grumpy and wanting to do the easier options that allow me more rest and recuperation will help me in that moment I think. Additionally, I'm also mindful that whatever I do, I'd probably want to undo it once I'm past the passes to get back to the stock gearing that's a pretty good sweet spot.

Keeping in mind that perspective, the front sprocket swap will be a strap to stop the rear wheel rotating, 4 bolts to remove covers, 2 bolts to remove the sprocket, some blue Loctite for good luck[1] and the rear axle nuts plus tensioning bolts on the rear to adjust the new chain tension. That doesn't sounds so bad. The rear sprocket swap is the exact same operation, except it also requires pulling the wheel off and reinserting it with finesse, rather than just loosening the bolts for chain slack adjustment. That sounds like tired me wouldn't want to do that. The actual sprocket swap looks pretty easy, it's 4 nuts and some gentle persuasion to free the sprocket.

Then I'm also mindful that whatever I'm doing, I'm probably doing it twice because fiancé with matching bike right? Unless they're doing their own wrenching, in which case you have the same discussions for mindset and fatigue, but for two different people.


There's a saying with tandem bicycle riders that "tandems will get you where you're going faster and that it's especially true if you're referring to marriage or divorce". Speaking more generically from past experience, tis better in both the explicitly obvious but also the more subtle nuances to discover how such a hardship is endured as "fiancé" than as "wife".

[1] it's always lucky when bolts that are supposed to stay tight do actually stay tight

Might be the best investment he ever made! I wonder if they will ever put up wallpaper together? TWILIGHT ZONE episode 2022

 

[SLO]

I have a 13 tooth on the way. Now if I want to gear it down some more,do I put a 41 tooth on rear and leave 13 tooth on front or go bigger on rear and put 14 tooth back on front? And would what is actually readily available, be the major real world factor in deciding? And what about size sprockets? 480 to 420 is it? Then what about chain length and type/size? I don't need to go over 50 mph for long stretches, but it would be nice to be able to climb a mountain at 50 mph. Downhill is not a problem. I have been riding in the highest elevation in the state. As well as adjacent states, NC. TENN. VIRGINIA. All within a hour and half ride. Can you give a bit of advice. I will try 13 tooth on front first. I wish I had done that in first place. 1500 miles on bike and am starting to learn to ride. M.C RIDER on YOU/TUBE has helped. I started watching while waiting for bike to come in.

 

[m in sc]

you go to a 13 you probably wont hit 50. the speedo says you will as its driven off the output shaft, not the wheel, but the gps will tell a different story. 428 is stock. you can fit a 420, ive done it but not nec recommended or necessary.

 

[ichibancarlisimo]

I didnt have any trouble getting up hills in Oregon. 1st gear climbed all hills I tried. I did get stuck in mud and snow pack but I would lift it out and this bike just kept going. I have stock tires and sprockets. I would like to try a 41t in the back.

 

[SLO]

you go to a 13 you probably wont hit 50. the speedo says you will as its driven off the output shaft, not the wheel, but the gps will tell a different story. 428 is stock. you can fit a 420, ive done it but not nec recommended or necessary.

I sometimes can't get to 40 mph in third uphill,bogs down. That is with 14 tooth sprocket. Hwy 16 Mouth of Wilson to Sugar Grove Virginia.It was the steepness of hill. From Konnarock to Mount Rogers good in third 40 mph on climb, but pulled snorkel out partway do to bogging down. I think it helped,but it could be the grade reduced after I did. I had the road to myself all the way from Taylor's Valley to Konnarock on to Mount Rogers back to 58. Had one car pull behind me on way to hwy 16 after getting on 58, left it behind. TWISTY. It was when I got on hwy 16 when a couple of cars got behind me,pulled over twice to let them by, but it was about 3:30 in afternoon and that is when traffic starts. It is dangerous to be on road at certain times of day,was a Wednesday,but most traffic on that road at that time would be locals in a hurry home or other reason. Time of day ,and day of week should be considered when going uphill, as well as direction of traffic. Afternoon sun when heading west ,on clear days can blind drivers at that time of day as well.

 

[SLO]

you go to a 13 you probably wont hit 50. the speedo says you will as its driven off the output shaft, not the wheel, but the gps will tell a different story. 428 is stock. you can fit a 420, ive done it but not nec recommended or necessary.

I wonder what affect the 3/0 Shinko 244's have on speedo? I put them on front and back,and they are definitely bigger.

 

[SLO]

I am sure it cut down speed, but I actually feel better on pavement than stock tires on twisty roads.

 

[ichibancarlisimo]

I did 64 mph going down Highway 26 by Mt. Hood but only 36 mph. going back up. They have loaded down 53 wheelers going up that can't go that fast.

 

[SLO]

420 is the OEM chain size, 428 is stronger and a more commonly available x-ring and o-ring type chain so it's an upgrade. The rollers have a larger diameter on the 428 chain so you should replace both sprockets to match the chain size if you upgrade to it.

---
Correction: OEM chain and sprockets are all 428
You should still replace all as a matching set since they are wear items (and not very expensive)

I just got a JTF 273.13 sprocket. It says on bag S.A.E. 1049/SCM420 on package,teeth a little bigger on top. Fits?

 

[m in sc]

the effect of the tire is easily figured out by measuring the diameter of the larger tire and the diameter of the old tire (both mounted and aired up). this will give you the percentage difference.

for example old tire is 22 inches tall, new one is 23 inches tall. (not actual measurements, just an example). about a 4.5% difference.

sprockets are (stock 14/39) 2.78 rear drive ratio, new ones are 3.0 (13/39).

as far as the sprocket, there will be a noticeable width difference between a 420 and 428. will the 420 work? sure. but wont be easy on the chain. IF you want to swap to a 420 (more than strong enough for this bike) all the grom parts will swap (front and rear direct bolt on) and there's a broader aftermarket variety available by a long shot. Ive seen bikes pulling well over 25 hp on 420 chains with no issues.

 

[dmonkey]

I just got a JTF 273.13 sprocket. It says on bag S.A.E. 1049/SCM420 on package,teeth a little bigger on top. Fits?

The JTF273 is for a 428 chain according to their website, SCM420 is the alloy used and not 420 chain size.

JT Sprockets: Catalogue

 

[SLO]

The JTF273 is for a 428 chain according to their website, SCM420 is the alloy used and not 420 chain size.

JT Sprockets: Catalogue

Thank You!, FFFing LOVE IT! Should be STOCK O.E.M. !!!

 

[SLO]

the effect of the tire is easily figured out by measuring the diameter of the larger tire and the diameter of the old tire (both mounted and aired up). this will give you the percentage difference.

for example old tire is 22 inches tall, new one is 23 inches tall. (not actual measurements, just an example). about a 4.5% difference.

sprockets are (stock 14/39) 2.78 rear drive ratio, new ones are 3.0 (13/39).

as far as the sprocket, there will be a noticeable width difference between a 420 and 428. will the 420 work? sure. but wont be easy on the chain. IF you want to swap to a 420 (more than strong enough for this bike) all the grom parts will swap (front and rear direct bolt on) and there's a broader aftermarket variety available by a long shot. Ive seen bikes pulling well over 25 hp on 420 chains with no issues.

I had not received bike before checking out forum.My initial query was to increase power as to the safety aspect . If I had read forum before getting bike my issue would have been more easily remedied. As for my request for advice was to access more power ,your response was accurate, but my lack of knowledge prevented me from asking the RIGHT QUESTION! and in that lies the solution. DAMN, much safer, has enough torque to go forward before it falls over and safer as not to have to look back as often.If it runs better,does that cause it to run even better due to EFI allowing more fuel. DOUBLE BENEFIT? Should be stock OEM.

 

[SneakyDingo]

While we're on the subject of sprockets, would the JTF274.13 be compatible as well? I'm trying to figure out how you knew that the JTF273.13 was the right one.