Bonneville America Forums Forums Technical Forums Performance Mods 18T Sprocket

I'm thinking of switching out my 17t for an 18t front sprocket to reduce the need to shift into 4th gear around town at the 40mph range. How has this 18t sprocket worked for anyone who has done it. Thanks.

I had mine on for one day and switched it back. Other people love it and will never go back. Depends on your riding style. Which bike do you have? New Speedys now come with an 18, I believe. PM me and I'll send you mine cheap.

I'm a 17t rider myself, but then I don't usually shift into 4th until I hit 50. The 18 is the most popular choice around here. For $20 each + shipping, it's cheap enough to try all of them and pick out which one suits you best.

I agree with Derek (Sal), try more than one, but give it a chance. I've been using the 18 for about a year and a half. I definitely prefer it highway riding as well as around town riding solo. Sunday riding with my wife 2-up makes me miss the 17. With the 18, 5th is more like an overdrive. I don't usually use 5th below 60. It makes highway cruising of 75-80 a lot smoother.

Going up a tooth also makes the gears slightly taller where you would tend to stay in each gear a bit longer. The only negative of the 18 to me is that it cuts down on quick starts if you're heavy or riding 2-up. Also, I probably wouldn't like the 18 if my bike were stock. Less restrictive exhausts, no AI, re-jet, opened up airbox, UNI - all gave the bike a noticeable power increase. Without at least those changes, I'd probably stick to the 17.

I thought about going back to the 17 and may try it again, but I've gotten quite used to the 18 now. There's probably a reason that is what's stock on all the new models.

I love my 18, but I live on flat ground... I may switch for a mountain ride later this year.

I like the way my bike runs with a 17T and have not tried an 18T, I am patiently waiting for a 6th gear to just appear. I am always going for 6 maybe one of these days it will be there!

I figure you are talking about cruising at 40? 3rd gear for me.

I'd suggest you wind her out a little more and keep the 17. 40 in 4th.... you might be lugging her a bit. What RPM are you turning at that point?

I love having the 18T. 5th gear, 75 mph, 4000 rpm.

Soren

I like the 18 but not enough to give up the grunt of the 17. My bike came wit the 18 stock, and it saw about 2500 miles before I changed it. I run 90% in town, with the exception of a 3 mile jaunt down the slab at 75mph to the gym at lunch. I turn about 4200 at 75. I'd like to try the 16, just for grins.

What would be the advantage to going to a 16T? I see a range from 16-19 on both newspeedmaster.com and bellacorse.com

More grunt off the line, pulling up hills, or 2up. The 2005 and back Speedmaster came with 16's stock.

The down side is even higher RPM on the freeway. 90% of my riding is in-town back roads and side streets.

Since I do a lot of long distance riding I love the 18T. I don’t feel I’ve given up anything on the performance of the bike. It also helps with the gas mileage.

Gene

I come down the 4 lane, turn off & head up thru the resedential area. I kick it down from 5 th into 4 th and come up thru town at 25 mph in 4th & my bike is just as happy as can be. 05 america 18 tooth. Other than that, the only reason to go to a higher front sprocket is your 5th gear highway rpm's.

jerry

I spoke to the guy at the shop and he said that I might need a new chain if I went to an 18t sproket. Since no one mentions this on here I'm assuming that I most likely wouldn't need a new chain.

...But we all know what happens when you assume. Has anyone here needed a new chain after switching from 17t to 18t?

No new chain is needed and you'll like the the smoother rpm's at cruising speed......ANGELIS

No new chain needed as far as length but if your sprockets are worn it is a good idea to do chain and both sprockets.

Negative on the chain. I've run 16, 17, and 18 with the same rear and chain. my next move will be a 7 with the bigger rear.

many people get a bigger rear with age

Well the bikes been dropped off for some maintenance. I'm getting new tires, front brakes, fork seals, fork gators, and an 18t front sprocket. I'm going out of town for a week but when I get back the bike should be done. I'll let y'all know how I like the new sprocket.

P.S. I get to go to Wrigley Field next Tuesday to see the Cubs vs. Dodgers! Go Cubbies!!! (I'm actually a Padres fan but I can root for the Cubs since they're playing against the hated Dodgers.)

I thought it was just me that thought sixth gear would work if I just keep trying to select it!


Sooner or later.....

Cheers
Wendell

LOL! Sounds like an 18t sprocket is in your near furure too. It's one the best, least expensive mods you can do.

Now just imagine an 18t and a six speed tranny

Soren

I have just placed a 19 tooth on mine because I was still trying to change up on the freeway ( or the excuse we might call a freeway in aussie)Have found it very strange it appears faster in first three gears 4th being a top and 5 overdrive at the moment I do like it but have yet to run through a couple of tanks of petrol to see milage
18 is good though

I am running the 16t at the moment and though I like the extra pickup for around town riding, on the highway I am running almost 5k at 80mph and my gas mileage dropped almost 10mpg.

Timely subject for me. I had an 18t for two years and just switched back to my oem 17t today.

I love the 18T and would never go back. Plenty of power in the mountains and lazier on the highway.

Make it a 17 and you gotta deal . But really, a six speed would be great.

Soren

Okay...

Guess I will head on over to Brents site and order one...

Any hints on installing it??

Cheers

Wendell

1. Remove Sprocket Cover
2. Take a large screw driver and straighten the large washer tab away from the nut.
3. Attach a 36mm socket and long breaker bar or large rachet.
4. Have someone hold the rear brake while you loosen the nut.
5. Loosen the chain all the way.
6. Remove the sprocket.
7. Reverse the steps.

Please consider a new locking washer for best results. They weaken easily when you bend them more than once.

Pat (Dinqua) has some great step-by-step instructions here http://www.dinqua.com/Triumph/sprocket1.html

Soren

use a side that hasnt been bent yet

It surprises me how most folks here wrap 'em under normal/cruising conditions.
I'm more like Jerry, though I have a 17.

I just picked up by bike from the shop and the 18t sprocket is awesome. At times I was going around 90 and the engine was nowhere near the rpm's it was when the 17t was on.

I can tell that the acceleration is a little slower but not that much of a difference.

Oh...and the Cubs game wasgreat too. We sat about 10 rows back behind home on bit on the third base side. Too bad the d*mn Dodgers won the game though.

I read this post and just changed from a 16 to a 17 tooth front sprocket today on my '03 Speedmaster. I was hitting about 3200 rpm at just 50mph with my 16 tooth.

I now really love the 17 and wish I had went to it before now. I didn't lose very much roll on power in any gear. The big plus I saw today is that it is a lot more comfortable at highway speeds over 60mph with the lower rpms. I was a little afraid that an 18 toother wouldn't have been my cup of tea for riding around town.

Bob

Personal preferences aside, there is a science to tuning for overall performance. This excludes track setups (shouldn't apply to us anyway), and I don't advocate doing this on public roads or without proper safety gear.

Your bike should be able to reach red line in top gear, but no more. If you are running a set up that won't allow your bike to hit red line, the setup is too tall. If you hit red line early (like it wants to go through the rev limiter) you are too low. The latter is harder to identify, since most of won't know we are over-geared until we run a setup that won't reach red line in top gear.

Keep in mind it is a ratio. The optimum setup might be a combination of front and rear changes.

Cool info. Thanks.

Soren