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19 tooth front sprocket

14K views 33 replies 22 participants last post by  rode2rouen 
#1 ·
Recently purchased this from British Customs after reading about the rpm lowering on the highway which is the main part of my daily commute. So, I slapped it on and immediately noticed the taller gearing on the bike. Basically, each gear became 10 mph taller, 5th gear not being engaged until 60 mph or greater. The new sprocket does not have the rubber cushion, so it is a bit louder noise wise. Makes you remember you have a chain underneath your seat. My take away after a couple of weeks is that is works fine. No more looking for a 6th gear with the added benefit of the speedo being accurate. Another change is that downshifting does not brake the bike as much as usual. I am not sure this is a good thing, but it is easy to get used to it.

The job itself does not require a lift, just the tools and knowledge of chain adjustment.

As usual, I’m torn between stock gearing and this modification. Anyone make the change and stick with it for the long term? Mike
 
#3 ·
The '07 I recently bought has a 19 tooth C/S sprocket, fitted by the previous owner.
I've only been able to put a couple of hundred miles on the bike so far, highway and surface streets, but I don't think I'll be changing.
The bike just "feels good" as is.

YMMV


Rex
 
#5 ·
The '07 I recently bought has a 19 tooth C/S sprocket, fitted by the previous owner.
I've only been able to put a couple of hundred miles on the bike so far, highway and surface streets, but I don't think I'll be changing.
The bike just "feels good" as is.

YMMV


Rex[/QUOTE

You only put a couple hundred miles on the bike but yet you claim to be the expert on telling me this bike does not need a fork brace? I've got over 250,ooo miles on these bikes.
 
#6 ·
I installed mine a month ago and actually prefer it while doing my inner-city commute. I had always been annoyed while riding in city traffic, I'd be riding at a speed that was a little too fast to stay in first and a little too slow to stay in second. I was constantly shifting up and down between the two. The 19 tooth sprocket certainly helps with this nuisance. It's been too cold for highway riding, but I'm excited to experience the difference.
 
#7 · (Edited)
I've used a 19 tooth sprocket on this bike a couple times. It works OK if you ride on level ground.

For me living in an area with mountains out my back door, the 18 tooth work better. I could even get by with a 17 tooth in this area. So the type of terrain can be the deciding factor.

These bikes originally came equipped with 17 tooth sprockets and then when they went to the 865 engines, they switch to the 18 tooth sprockets. My 2003-T-100 came with a 17 and then my 2004 Thruxton equipped with an 18 tooth.
 
#8 ·
I run a 19t sprocket and love it. It runs about 70mph at 4000 rpm and I like the relaxed feeling. If I want to run quickly through the gears I use the full rpm range and each gear is taller so I don't need to be constantly shifting. I wouldn't want to go back.
 
#11 ·
I like all kinds of riding so it's not unusual for me to jump on an interstate and crank it up to 80mph and just cruise along. I like the freeway because 80 normally won't get you a ticket. The 19t performs great in this scenario.

When I'm carving my way around I just keep the revs up and the 19t works fine there also.
 
#12 ·
Interesting... I found 80mph indicated to be a sweet spot on the freeway as well. A short (13 miles down, 13 miles back) twisty river road, can be run hard without shifting (3rd gear) betwixt corners. Lots of fun!
I do want to get a cheep gps to check speedo accuracy, though.

Rex
 
#15 ·
Interesting.. When I replaced the OEM sized rear tire with a slightly taller 130/90-17 the RPM at 70mph dropped about 300 RPM to 4,000. Apparently the same as going to a 19 tooth sprocket. I like it just fine as is and would not put the 19 tooth on with this tire.
 
#17 ·
I've tried 17 stock 18 and 19 tooth plus I run a 140/80 rear tyre. Bike has TTP tune 2 with associated mods.

Didn't like the 17, OK if your in the city or hills I guess.

19 has been on for 2500 Klm and has its good and bad points.
Better fuel economy, so long as your taking it easy. Up the pace and you'll need to rev more and hold gears longer.
Good on the flat but hills and you need to select the right gear or you'll fall in a hole and be looking for a lower gear.
Couple of tight up hill hairpins had me in 1st with sweaty palms.

Think Triumph got the gearing pretty right for all round use with the 18 (for a 5 speed) 6th gear would be nice....water cooled anyone?
 
#18 · (Edited)
Moving to a 19 tooth front sprocket is exactly what I will do soon for my '07 T100. I have done similarly with my Sportster and have not regretted it. Bikes are geared by mfrs. with the majority of their customers in mind who prefer maximum acceleration but I like a more calm highway cruiser. One other benefit of a 19 tooth front sprocket over an 18 tooth is that your fuel mileage will be improved. When you do this you will immediately feel the loss of acceleration but after a week you will not notice it.

If you encounter a hill, downshift as needed.
 
#21 ·
Well it's not going to be a huge change, it's only a 5.5% difference in gearing so even if there was no loss of efficiency (never gonna happen) it would only be 2.5 mpg better fuel economy.

I noticed it touring with tank range, got 273klm (170miles) from a tank 13.2 litres. Never been close to that before.
 
#20 ·
I will look into the 19T after I improve the performance of the engine as I ride two up a lot and over windy mountain roads so I will require the extra power to feel good about this but look forward to it as a 19t on the highway would be excellent


Sent from my iPad using Tapatalk
 
#22 ·
I put on a 17 about 20k ago...love it! Still has manners but I enjoy the increase in response and pep. Great in the mountain twistys. Pulls hard out of corners. I do some hwy miles between GSO and RAL...no prob. Spins at 5K at indicated 80mph. The 865 loves to live in the 4-5k rpm range. I've actually thought about a 16
 
#23 ·
........ My take away after a couple of weeks is that is works fine. No more looking for a 6th gear with the added benefit of the speedo being accurate... ..
Perhaps you could explain how changing the front sprocket would have any effect on the accuracy of the speedometer? Is speedometer not regulated by wheel speed?
 
#26 ·
Had the 19/41 combination on my 07 Thruxton for 25000 kms now and will never go back. Love the relaxed feel on the highway and the flatslides give it the required urge through the twisty bits. Best of both worlds. Originally had 18/39 fitted but didn't like the revvy nature.
 
#28 ·
Several years ago I began riding my 2006 T100 with a 19 tooth sprocket, plus a switch from a stock 130/80-17 to a 130/90-17 rear tire. For the type of riding I do as a senior on the Triumph (compared to riding my Warrior 1700 in a bit more assertive fashion ), which is mostly two up and in the flat lands with some foothills riding, the two changes have been a real positive for me. It's almost like having a sixth gear when riding in the 50 - 70 mph range.

If someone is interested in determining the amount of rpm changes resulting from gearing changes for most bikes, a terrific source is the great Website Calculator, Gearing Commander --- http://www.gearingcommander.com/ . G/C has a large array of gearing information on stock bikes as well as determining the affect on rpm's by changing gearing. If your interested in that type of information it's definitely worth checking Gearing Commander's Website.

According to Gearing Commander, the 2006 T100 with the stock 18 tooth sprocket, and stock rear tire, the rpm's at 60 mph are 3,579.

By switching to a 19 tooth sprocket, at 60 mph the rpm's are 3,390.

By calculations, changing the rear tire to 130/90-17 --- and when the tire is fairly new --- and with the 19 tooth sprocket, the rpm's drop to about 3,259, which is about 91 % of the stock rpm's --- again, almost like a sixth gear.

With respect to gas mileage, given those two changes, as one example, if your bike is averaging about 40 miles per gallon stock, then with those two switches there could be as much as about a 10 % improvement, or about 4 mpg increase, depending obviously on many other factors.

As has been mentioned in various postings here, if the riding tends to be somewhat more aggressive and if there's more landscape gradients involved then it makes sense to stay with the stock 18, or perhaps a 17 tooth front sprocket for even more spirited riding styles.

After having ridden the bike for some time both in stock form and with the tire and sprocket changed, I like the more relaxed ride with the current setup for my riding genre. Again, before making the switch it felt like the bike could use a sixth gear, and now, that feeling has gone away with the larger sprocket and rear tire. For me and my riding style on this particular bike, the Triumph is now ideally geared.
.
 
#30 ·
I put a 19 on my t100 a while back and also noticed the sound due to no rubber thing. Glad to know somebody else hears that, but since getting Togas (replacing TORs) I don't hear it now. By the way, I get worse gas mileage on twisties (most of my riding) but better on the highway, and I like the taller gearing.
 
#31 ·
I replaced the stock 17T on my '01 Bonneville with a 19T about 15,000 miles ago and never looked back. Replaced my stock chain last week after 25,000 miles with a 525 DID gold X-ring 104 link chain, and there is no noticeable wear on the sprockets.
 
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