Sprockets for highway cruising?

[Exandriel]

I'm about to drop a new chain on the bike and figured I ought to do sprockets too, thought I could get more comfortable cruising rpms. I was doing some reading on the subject and was wondering what people are running on theirs. I live in Texas so highway cruising's gonna be around 80 mph and was seeing that others on fz09s were gearing to a 17/43 and was thinking about that on my FJ if its possible on this bike to fit a 17 in the front, also wondering if I would need to change the linkage on my chain if I did make a large change like this. Does anybody have any recommended chains/sprocket models as well?

[norcal616]

You can switch to a 520 sized chain and sprockets for better availability/size selection at stores... Just use the proper strength chains( chains for 1000cc sport bikes such as R1 type of strength)

[betoney]

4 hours ago, Exandriel said:

I'm about to drop a new chain on the bike and figured I ought to do sprockets too, thought I could get more comfortable cruising rpms.

You can find what you are looking for at Sprocket Center.  They are very knowledgeable and helpful over the phone if you need guidance in selecting your final gearing.

One thing to know when changing the final drive gearing, it not only affects highway cruising speed, it affects every gear at all rpms, and changing both front and rear is a very big difference, your acceleration will be greatly reduced but top speed will be increased.

As an example, for quicker acceleration most riders change one tooth smaller front sprocket or 2 teeth bigger on the rear, usually not both.  Again, call Sprocket Center and discuss your needs and see what they recommend.

 

[dbeau]

I put 17/43 sprockets on mine this last time around because my commute is mostly highway 80-90 mph and I wanted to drop cruising rpms. 

The 17t front sprocket barely fits. You definitely have to squeeze it in there and I'm pretty sure afterwards the chain rollers rub against the rubber piece in front of it but I don't think thats a problem. It'll probably just wear it away a little bit and be all good. Also, the rubber/plastic chain guide thing that sits on top of the swing arm gets worn into a little bit but again no big deal. Going on several hundred miles with this setup and no issues.

As for performance, the bike is WAY more tame. It pretty much takes all the hooligan out of the bike but its still fast. You can still bring the front wheel up in first but you have to roll off and hammer back on.

While in theory top speed is increased the bike just doesn't have enough power to go much past 130 even with stock gearing. Probably a lot to do with wind resistance.

 

Check out 

Gearing Commander ⚙

and you can play with different gearings and see how the RPMs change and stuff. 

Edited July 26, 2019 by dbeau

[chitown]

If you're at stock 16/45 110 links now 17/43 is pretty large change. Sprocketcenter will probably recommend changing the number of links to accommodate so make sure to check with whomever you order from to make sure. You would be going from a 2.81 ratio to 2.53, an 11.2% change. Typically I've made about half of that change but it depends on how far you are away from your target rpm/speed now and what you're willing to live with losing for acceleration.

For me FJ comfortable cruising rpm is only a bit less than what I"m at 80 mph (per GPS). Swapping the rear sprocket is a bit less involved than front should you end up unhappy with what you're losing down low and going back to stock so I'd start with changing the rear. For me that would be one tooth in the rear, 44, for a 2.3% change. 

Many sites have calculators to show you the effects of gearing changes. 

[texscottyd]

Hi @Exandriel - Greetings from Houston.  I totally understand the Texas freeway situation...  when it’s not at a dead stop, ambient traffic flow around here is typically in the 85-ish mph range.   

That said, 17/43 is a huge swing from the stock 16/45 gear on the FJ.  I personally find the stock gearing relaxed enough up into the mid-90s cruise speed, which is where the aero realities of a light bike with a small windscreen start pushing my comfort limitations.  If you search ‘stock gearing’ on the forum, you’ll find lots of discussion and opinions on the topic. 

As @betoney mentioned, a big change impacts the gearing everywhere.  My ride-ability concern would be city traffic intersections, where a simple right turn at an intersection has the bike right between first and second gear...  I rode a friend’s bike with this gearing quirk, and it drove me insane.  A little goes a long way on gearing changes.    

Good luck!   

[dbeau]

17/43 uses same size chain as stock -- 110 links

 

[nhchris]

See the section on taller gearing in the CycleWorld Tracer 900 article.

[Exandriel]

Whats the benefit of having the dampend front sprocket? I'm having trouble finding a 17 with dampening.

[betoney]

5 hours ago, dbeau said:

I put 17/43 sprockets on mine this last time around because my commute is mostly highway 80-90 mph and I wanted to drop cruising rpms...

...As for performance, the bike is WAY more tame. It pretty much takes all the hooligan out of the bike.

That right there says it all...  ☹️

[texscottyd]

4 hours ago, betoney said:

That right there says it all...  ☹️

To ‘de-hooligan’ a CP3 should be a criminal offense... 

[wordsmith]

On 7/27/2019 at 2:44 AM, dbeau said:

I put 17/43 sprockets on mine this last time around because my commute is mostly highway 80-90 mph and I wanted to drop cruising rpms. 

 

I also belong to the school that feels that at higher (cruising) speeds the gearing is way too high.   With two long-ish ~4500km trips coming up I'd like to consider these changes, accepting that it seems easy enough to return to stock later.

To give me a yardstick, could someone with these 17/43 sprockets please advise what changes they make to engine revs at exactly 100kph/ 60mph (100kph is the most common speed-limit on roads here). Thank you!

[justplainbill]

1 hour ago, wordsmith said:

 

To give me a yardstick, could someone with these 17/43 sprockets please advise what changes they make to engine revs at exactly 100kph/ 60mph (100kph is the most common speed-limit on roads here). Thank you!

Using chitown's calculation of an 11.2% reduction with 17/43 sprockets in final drive ratio, you can multiply your observed engine speed (RPM) at a given road speed by 88.2 to determine engine speed with the higher (lower numerically) ratio at the same road speed.  So if your engine speed is 5000 RPM at 75 MPH with stock gears, it will be 4410 RPM at 75 MPH with  17/43 gears. (I don't happen to know the RPM at 60 MPH and it's too damn hot here to ride down the road to find out.😀 )

Edited July 28, 2019 by justplainbill

[betoney]

2 hours ago, wordsmith said:

To give me a yardstick, could someone with these 17/43 sprockets please advise what changes they make to engine revs at exactly 100kph/ 60mph (100kph is the most common speed-limit on roads here). Thank you!

@wordsmith - Did you check out the link to gearing commander website that @dbeau posted above?  you can play around with any sprocket combination and any speed limit or rpm for answers.

Also @nhchris posted a link above as well to an article using that exact gearing. 

" I felt that Yamaha missed the mark on the overall gearing as the bike spins 5,400 rpm at an indicated 80 mph with the stock 16/45 sprocket combination...The gain was 10 mph at the same engine speed, so 5,400 was now 90 mph, with 80 mph happening at 4,800 rpm". 

[wordsmith]

The gearing commander website doesn't want to let me play, wants me to disable the Ad-Blocker function (which I fully understand and am more than happy to do), but it won't disable.   But chitown's calcs helped after I had warmed-up my abacus, and I'm happy at that.    Even so, if anyone has observed the points of interest that I gave (rpm @ 100kph/ 60mph with 17/43) I'd like confirmation if you please!   TIA...