Final Drive Swap: 6th gear solution?
- Thread starter Mr. BR
- Start date
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Chuck35
Well-known member
Sorry I wasn't so clear in conveying my thinking. 10% of the RPM @ cruising speed.
escapefjrtist
Searching for Dry Roads
^^^^Huh? Redline has nothing to do with the on-going discussion. With the ratio change, the engine is turning 10% less revs in 5th gear at speed, that's all.
For the OP -- Great write up and information, thanks for the post.
--G
For the OP -- Great write up and information, thanks for the post.
--G
SoCalFJR1300
Well-known member
Blind Squirrel
Well-known member
He is not working at redline;
3021 / 3357 = 0.8999106344950849
2939 / 3267 = 0.8996020814202632
With rounding I would call that 10%.
Hello again!
Mr. BR checking back in on our discussion… and thanks for the compliments!
I realize that this change is not for everyone and many folks find it completely unnecessary. We could look at it as simply another farkle, no different than upgrading your windshield or changing your seat I suppose. I wasn’t looking for better gas mileage or hoping to make the bike last longer through fewer revs (that would be silly of course). It really was a “feel” thing for me because at freeway speeds, 5th gear felt like 4th and I was looking for another gear every time. It just felt busy, not relaxed, annoying!, and it hit me the day I bought it. Perhaps it was my 5 yrs of ST1100 ownership that contributed to that mind-set (for lack of a better term). The ST is a bit more “relaxed” than the FJR in just about every way. On the other hand, this is not the first bike I’ve geared “up” either (chain drives before). Money wise… yes, it was $300 plus shipping between PA and CA just for a few hundred less revs/mile but the end result was significant for me and worth every penny. Time wise, not counting my “research”, it took about 90 min to swap the FD unit and it’s only a few more steps beyond pulling the rear tire. Gas mileage? Seems to be about the same as before so far (~40 mpg) but most of my riding is a daily 32 mile RT commute with a mix of freeway and city streets (not ideal for MPG). The bike still accelerates hard through the gears and the roll-on, while perhaps a little softer now, is still more than adequate. I’m not shifting any more or less but I certainly feel the need to drop down to 4th sooner than I did before when slowing in 5th (like when traffic slows but then you speed up again). I’d like to post up a chart of some sort that illustrates the RPM change across all 5 gears so I’ll try to work on that.
John F @rmsportmax did tell me that it was one of his FJR riding buddies (a LD rider apparently) who first asked him about doing this gear swap for the FJRs but he didn’t say what the guy was looking to gain… Better mpg or something else? Anyway, if anyone else decides to take the plunge on this gearing change, but sure to post up with your findings.
Regards,
Mr. BR
Note: Thanks to “mcatrophy” for pointing out the speedo pick-up differences between the GEN1 and the later bikes (I completely missed that one!).
Mr. BR checking back in on our discussion… and thanks for the compliments!
I realize that this change is not for everyone and many folks find it completely unnecessary. We could look at it as simply another farkle, no different than upgrading your windshield or changing your seat I suppose. I wasn’t looking for better gas mileage or hoping to make the bike last longer through fewer revs (that would be silly of course). It really was a “feel” thing for me because at freeway speeds, 5th gear felt like 4th and I was looking for another gear every time. It just felt busy, not relaxed, annoying!, and it hit me the day I bought it. Perhaps it was my 5 yrs of ST1100 ownership that contributed to that mind-set (for lack of a better term). The ST is a bit more “relaxed” than the FJR in just about every way. On the other hand, this is not the first bike I’ve geared “up” either (chain drives before). Money wise… yes, it was $300 plus shipping between PA and CA just for a few hundred less revs/mile but the end result was significant for me and worth every penny. Time wise, not counting my “research”, it took about 90 min to swap the FD unit and it’s only a few more steps beyond pulling the rear tire. Gas mileage? Seems to be about the same as before so far (~40 mpg) but most of my riding is a daily 32 mile RT commute with a mix of freeway and city streets (not ideal for MPG). The bike still accelerates hard through the gears and the roll-on, while perhaps a little softer now, is still more than adequate. I’m not shifting any more or less but I certainly feel the need to drop down to 4th sooner than I did before when slowing in 5th (like when traffic slows but then you speed up again). I’d like to post up a chart of some sort that illustrates the RPM change across all 5 gears so I’ll try to work on that.
John F @rmsportmax did tell me that it was one of his FJR riding buddies (a LD rider apparently) who first asked him about doing this gear swap for the FJRs but he didn’t say what the guy was looking to gain… Better mpg or something else? Anyway, if anyone else decides to take the plunge on this gearing change, but sure to post up with your findings.
Regards,
Mr. BR
Note: Thanks to “mcatrophy” for pointing out the speedo pick-up differences between the GEN1 and the later bikes (I completely missed that one!).
mcatrophy
Privileged to ride a 2018 FJR1300AS
I've a utility that does gearing calculations, it is fully editable, and defaults to a "standard" GenII FJR, click here.
Changing the gearing for a modified GenII with "your" final drive gives this (note the graph is auto-scaling, so the two graphs don't necessarily directly compare, but the tables of mph v rpm do).
If you know all the ratios for a GenI, you can easily edit it appropriately.
It can be edited for virtually any wheeled vehicle, as you can change the number of gears, the number of teeth on each, also the tyre size.
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Chuck35
Well-known member
I have an ebay final drive on the way to John for new gears as we speak. I hope to have it in the bike next weekend.
Thanks for posting this!
Thanks for posting this!
We've all heard of the DarkSiders and the FatSiders. So, these gearing converts... what shall we call them?
They are gearing up, perhaps they are the "Up-Siders"?
They are gearing up, perhaps they are the "Up-Siders"?
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Chuck35
Well-known member
Top gears
Gear heads
I'm raising my gearing, now up yours
Gear heads
I'm raising my gearing, now up yours
RossKean
Well-known member
It would be interesting to see whether this increases or decreases top speed. You would be turning fewer RPM at terminal velocity but the ultimate speed depends on where you are in the torque curve (I assume we are power limited, not RPM limited at top end?).
Mr BR: Thanks for the info! Ever since I started riding, I've been looking for fewer revs at highway speeds. I kept buying bigger and bigger bikes (my old Kawasaki VN750 used to turn 5400 rpm at 70 mph. It always felt like I was riding a pissed-off bumblebee).
My 2005 FJR does 4000 rpm at 70mph. I don't know that 3600 rpm will will feel like night and day different, but I'm absolutely gonna try it. I called John Furber and made an appointment to meet next week to swap pumpkins. I'll report back on impressions and mileage. I'm excited about the possibilities.
When I owned a C10 Concours, there was a guy in South Florida who had a nice cottage industry changing gears on Connies. It was lovingly called "the 7th gear mod". Hell, I even put a gear indicator on my Gen1 FJR just so that I'd stop looking for another gear. I'm hoping this "farkle" makes a welcomed difference. AND...I'm going to buy a used pumpkin on sleaze-bay just in-case the mod doesn't live up to expectations.
Thanks again for doing the research!
Baz
My 2005 FJR does 4000 rpm at 70mph. I don't know that 3600 rpm will will feel like night and day different, but I'm absolutely gonna try it. I called John Furber and made an appointment to meet next week to swap pumpkins. I'll report back on impressions and mileage. I'm excited about the possibilities.
When I owned a C10 Concours, there was a guy in South Florida who had a nice cottage industry changing gears on Connies. It was lovingly called "the 7th gear mod". Hell, I even put a gear indicator on my Gen1 FJR just so that I'd stop looking for another gear. I'm hoping this "farkle" makes a welcomed difference. AND...I'm going to buy a used pumpkin on sleaze-bay just in-case the mod doesn't live up to expectations.
Thanks again for doing the research!
From an engine tone and vibration standpoint, you could just ride at 3600 rpm (63 mph) and that should be pretty close to how it will feel at 70 after the mod.
I could, but that'd be deadly dull. How about the converse, I ride at 77 with the same tone and vibration as 70mph before the mod?From an engine tone and vibration standpoint, you could just ride at 3600 rpm (63 mph) and that should be pretty close to how it will feel at 70 after the mod.
I really like the idea of turning fewer revs at the same or higher speeds. I wish I wasn't adding speedo error into the equation, but that initially seems to be part of the cost with a Gen1. Ah well......
Chuck35
Well-known member
HotRodZilla
GOD BLESS AMERICA
Top speed depends on elevation, incline and wind. Flat road with no headwind, the bike is limited by RPM. Any incline or headwind at all and its limited by power. Of course, if I was 50lbs lighter, maybe that wouldn't be the case. Oh...And I live at 5100 ft and spend a lot of time above 6k feet.
Chuck35
Well-known member
Using mcatrophy's utility, and adjusting for the car tire and final drive mod, top speed (9k rpm) goes from 169 to 190
lnewlf
Well-known member
Never do it..
nealopp
Active member
San Jose? I'll go ahead and just drop my bike off at your garage for the swap. Thanks! :-D
Thanks for doing legwork on this. I do miss having a 6th.
-Neal
Also San Jose, CA
Hey Neal..... if you're in San Jose, just keep your eyes open for a Blue Gen1 with Givi top case and what looks to be a really tall guy riding it (black pants, white helmet, hi-Viz jacket). My daily commute is up and down 87 past down town and the airport (Almaden to North SJ).
For the rest of you out there..... I had mentioned that with my new FD gear change, the bike still accelerated hard and the roll-on was still strong but perhaps a *little* softer.... no big deal. Today when leaving the metering light to enter the freeway, I went WFO in first gear and up came the front wheel for a nice 1 foot power lift.... surprised me a bit as I hadn't done that before pre-gearing change. Now, I DID have my top case loaded with my laptop (15lbs?) but I don't know how much that contributed to the unintended wheelie. It was fun but I'll be ready for it next time.
regards,
Mr. BR
For the rest of you out there..... I had mentioned that with my new FD gear change, the bike still accelerated hard and the roll-on was still strong but perhaps a *little* softer.... no big deal. Today when leaving the metering light to enter the freeway, I went WFO in first gear and up came the front wheel for a nice 1 foot power lift.... surprised me a bit as I hadn't done that before pre-gearing change. Now, I DID have my top case loaded with my laptop (15lbs?) but I don't know how much that contributed to the unintended wheelie. It was fun but I'll be ready for it next time.
regards,
Mr. BR
