Bonneville America Forums Forums Technical Forums Accessories 18 tooth users

Hello all, i just received my 18 tooth sprocket. Will i need to change the chain or is it long enough to work with the new sprocket?
Thanks

Chain length was fine on my 2003 TA.

BikerT

It's likley your existing chain will work fine. You might need to slightly change your driving habits with regard to when to downshift out of top gear though.

I recently installed a 19 toother, and in my humble opinion, the engine will lug at less than 3400 or so RPMs on the level or when climbing a grade. The 16 toother would pull fifth at 3,000, unless the grade was fairly steep. I shift into 5th now at around a speedometer indicated 60, which in reality is closer to 55 MPH. I like it this way, but that's just me.

Speedometer checker
http://www.xs4all.nl/~ator0437/Beta/index.htm
From the drop down, select Triumph > Bonneville > T 100 > Load presets. This chart will show you your actual road speeds, as opposed to the highly exaggerated speedometer readings, which tend to be around 5 to 8 MPH more than your true speed. I made a little RPM vs road speed chart for my tank bag, and typically gage my speed from the tach. A good rule of thumb on my bike is also to read the speedometer, and knock 5 MPH off the reading for a true speed, In other words, 70 MPH on the speedo is actually a 65 MPH travel speed. I'm fine with the speed limit on many ocassions, but 5 MPH below on a dry sunny day must get old for those behind me.

Sprocket changing destructions.
It is also easier to just hold the rear brake lever down while loosening the sprocket. Take the big nut off this way, slip sprocket off, slip new sprocket into chain, reinstall, hold brake again and tighten big nut. Adjust chain tension and away you go.
45 Minutes and 1 beer job .

Still trying to verify that the newer Speedmasters (865cc) have a stock 18t front sprocket. I am hoping, if that is the case, that I may soon be able to buy a chain and sprocket set, from TRIUMPH, and therefore be able to change both sprockets and chain without having to source the parts from different suppliers. As of yesterday, my dealer was still only able to pull up two part #s for the sets - one for the America (17t), and one for the SM (16t).

I am hoping that with the new model year launch, and subsequent catalog updates, we may see the new set part #, if that rumor is true.

For that matter - what do the new 2007 models come with? It would make since, if they both run the 865cc engine now, that TRIUMPH would consolidate their inventory, and show the same part set for both, assuming they now run the 18t front sprocket. That used to figure prominently in the model differentiation in the new model brochures, but it is no longer mentioned. Only styling cues appear to differentiate the two models today. Shame.

On the Bike Bandit Parts Page for Speedmasters w/engine numbers 211133 AND HIGHER, the info is:

23: SPROCKET,GEARBOX,18T
ENG NO 211133 AND HIGHER
5566151-001

The older SM part is: 16T
5566150-001

Both list at 53.83. Pretty outrageous if you ask me.
I don't know what the kit number is, but with it you can get the set of sprockets (w/18T) and chain for about twice the price of just the front sprocket.

I went to a 18 about a month ago and it does take some time getting use to it, but what a difference on the slab's or long runs no more searching for that sixth gear.

I also went to an 18 tooth about 4 months ago, at first I had mixed feelngs but after about an hour I said I couldn't see going back. Like Big Poppy said once you get use to it what a diffrence!

I show the following fifth gear numbers for a Speedmaster, with 43 tooth sprocket, & without the plentiful speedo errors

60 MPH

17 = 3700 RPM (59 mph)
18 = 3500 RPM (59 mph)
19 = 3400 RPM (60 mph)

``````````````````
70 MPH

17 = 4400 RPM (70 mph)
18 = 4200 RPM (71 mph)
19 = 3860 RPM (69 mph)

````````````````````````````

Pat, could you please clarify whether that 1 Beer Job is a Standard American Beer Job, or European Union Standard Beer Job. Normally, I go by the German National Standard Issue of Beer, Subparagraph B (in effect in Bavaria and Southern Germany), of 1 Standard German Beer Unit = 1 Liter....

Plain and simple. If you go up one tooth and the majority of your riding is two up (with passenger)then it sucks! Way to much down shifting. If you only ride solo then no problem.
Ride Safe
EZ

I ride about 50/50 2-up and have the 18/42 sprockets. I agree that the 17T is better on starts 2-up, but I still prefer the 18T. It's noticeably more comfortable at highway speeds and I rarely look for a 6th. The only drawback I see is some loss of quickness off the line. If you want to out drag the other bikes, stick with the 17 or go to a 16. I assume that's what the orignal Speedmaster was set up for, quick starts and hard stops (2 front discs).

I don't see it as too much shifting, in fact I think I shift less. I just adjusted WHEN I shift to the new setup and I have adapted just fine. The big definitely works for a living two-up from a stop on a hill, but otherwise I much prefer the 18T.

EZ, I didn't ask or consider whether your bike had any performance mods or not. I never had the 18T until after I had upgraded pipes, rejetted, and opened up the airbox. Without the performance improvements, I'm sure the difference in take offs would be more noticeable.

It looks like Triumph has agreed the 18/42 combination is best as they have it on all the new TAs and SMs, but they are the 865s with more low end torque. The 790 with performance mods puts it more on a level playing field with the 865.

EZ,

This was the first MOD I did prior to the performance upgrades and even when stock I really liked the difference.

It takes a little to get use to at first and your bike will lug around 3,000 going up hill. I often find myself in fourth gear on group rides, but the big differnece will be on the highway.

TBA's were not designed to be wheelie standers or to smoke the rear tire off the line, so the little trade off on startup is worth it. After awhile you do not even notice it.

The mods on my bike are : wide open pipes,rejetted carbs, opened up air box with UNI filter. Me personally, I don't like the extra added tooth. When I did the change and rode by myself it was fine!! But, I do at least 80% of my riding 2-up. I see the extra shifting when pulling up hill. Also there is a little more slipping of the clutch from a stop with 2-up. So to me that equals less clutch life. Again not worth it.So after riding with the extra tooth sprocket for about 2 months I decided to put the stock one back on. These motors are built to run there best at the higher RPM's. So I just added a tach and now I never look for that 6th gear. I know what RPM's the engine is runnig at in 5th gear so I don't try to shift. Just my opinion.
Ride Safe
EZ

Yeah, but but but... - lower RPMs from faster gearing can result in longer engine life, when measured across hours operated vs. cruise speed. It's a yin & yang thing.

I run a 19, and will agree the clutch will lose some life as compared to the other sprockets, but 4th to me is good for up to 60 MPH, (secondary roads) then on the highway I click into 5th at 60 MPH. It's very much like an overdrive.

I have to admit to a very similar background of driving geared fast run slow tractor trailers, with progressive shifting whenever possible, so I have those methods ingrained into my brain all day 6 days per week for 15 years. The 19 seems normal to me, but I can understand how many would hate it. It is a bit odd in some respects.

I replaced my chain/sprocket set two weeks ago, and went with the America set-up of 42t rear / 17t front, as TRIUMPH listed no set part # for the 18t front yet (could get the sprocket alone, but not in a chain set).

Observations:

I am seeing a lot of miles at 5k rpm in 5th.

I am not "searching" for 6th as much as I thought I would be. I just glance at the tach, and if I am over 70mph, and the tach says around 5k, I know I'm in 5th already. I reach for it every now and then, but only because I did not check speed vs tach first.

Coming off the 18t front, I like the extra torque on takeoff, and I like what the extra torque provides throughout the gear range. I remember now why I liked that stock 16t so well.

I think it is a little easier on my clutch, especially on takeoff, so it may help prolong the inevitable clutch change. I need to check my clutch cable adjustment, but I do not have any experience with that, so I have put it off. Nothing slipping.

I'm sticking with the 17t for the foreseeable future.

I'm in progress of getting rid of the airbox (having a bracket made for the right side cover) and adding K&N filters. My 865 came stock with 16/42 but I soon put on the Thunderbikes and 17T front. Now with my current setup (130 mains, drilled airbox, TBS needles) I'm loving that 17T sprocket. I'll probably keep it on even after dumping the airbox, just to keep that little extra torque.