• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Long 5th Gear

There is a shorter first gear available and I inquired about it when having my ‘93 R100GS trans rebuilt by a very well known airhead shop. I was advised they don’t generally install it because the difference is too great—1st gear becomes too low. So that mod was scratched from the request list.

Best,
DeVern
 
I'm wondering how shortening the first gear and lengthening the fifth gear would affect shifting. Usually, wider gear spacing results in more clunky gear changes.

.
 
I'm wondering how shortening the first gear and lengthening the fifth gear would affect shifting. Usually, wider gear spacing results in more clunky gear changes.

.

I don't think it is possible to get gear changes that are any clunkier than those of an Airhead. The first time I shifted from 1st to 2nd I stopped and looked back to see what had broken and fallen off the bike.
 
I have a 1990 R 100 GSPD, 2 years ago, while having the trans rebuilt and adding the circlip, I added the taller 5th gear also. it cost $250 or so, for the new gear. It has been a great addition, I usually cruise at 4,000 to 4,500 rpm, which puts me at 70to 75 mph. I would highly recommend the taller 5th gear on a GS, but that is not the bike the original question was about. on my 78 R 100 S, I can motor down the road at 80 mph no troubles.
 
I plan to take the PD to the national rally in Montana next year, hope to see you all at airhead central.
 
I have a 1990 R 100 GSPD, 2 years ago, while having the trans rebuilt and adding the circlip, I added the taller 5th gear also. it cost $250 or so, for the new gear. It has been a great addition, I usually cruise at 4,000 to 4,500 rpm, which puts me at 70to 75 mph. I would highly recommend the taller 5th gear on a GS, but that is not the bike the original question was about. on my 78 R 100 S, I can motor down the road at 80 mph no troubles.

Do you have any idea how many RPM's you're turning at 80mph on the 1978 R100S?

How about at 65mph or 70mph? What I consider around-town freeway speeds.
 
IIRC, my R100RS was turning 5,000 at 80, and, I think, 4,500 at 75, with the stock gearing. I thought the gearing was perfect for riding out West. The transmission had been gone through by Dave Anderson of Anderwerks, had the later shift cam, and shifted quite smoothly.

It was smoothest between 4 and 5 thousand, so that's where I ran it, in the higher gears. I've read that the 800's are smoother.
 
I understand the OP's original desire to lower his RPM's.
That said I always thought my 1978 R 80 [ different airhead for sure ] is geared just right for general touring.
Its very old tech wise these days, Tubes, points, carbs, but I still tour on that thing and I love it!
The way it handles, starts, sounds, simplicity to work on, appearance etc. I'll never sell that thing!
With new rear shocks and modern tires it rides pretty good!
Merry Christmas all you airheads out there:wave
Ride safe in 2020
 
A decade or so back, I swapped the 37/11 final drive for a 34/11 on my R80/7 and it made 70-75mph more comfortable in the sense that the engine wasn't spinning at 4500+RPM. It's such a torquey engine that I don't notice a difference at lower speeds/gears. I had the speedo calibrated to match the change and I'm happy with it.
:beer
 
I don't think it is possible to get gear changes that are any clunkier than those of an Airhead. The first time I shifted from 1st to 2nd I stopped and looked back to see what had broken and fallen off the bike.

Hahaha

My beautiful short-wheelbase red R75/5 4-speed Toaster Tank (now sold) was the roughest-shifting BMW (maybe any motorcycle) I've owned but it didn't matter to me. I had it for several years and grew to like that SLAM BAMM shifting of the Toaster.

I bought a pristine 5-speed R90/6 at the same time and it shifted much nicer than the 4-speed but it was still a little rough.

I remember when BMW brought out the new oil-cooled boxers (after they had aborted the phase-out of the boxer motor). I made a test ride on an RT model thinking I might go for one. I was shocked at the transmission. It was very clunky, much more than my very old Shovelhead Harley 4-speed (which I still have) ! I passed on the BMW. Then, when the much-touted 6-cylinder BMW touring bike was introduced, I was shocked at how clunky that transmission was for such a supposedly modern bike.

The fact of the matter is that BMW's, all the way up to the current models, are not known for slick shifts but they have improved over the years.

.
 
I am seriously considering one of the short low gears.

I just don't know that a 6 percent change would amount to much advantage. Also, I have questions about the single cog gaining that mechanical advantage by contacting the teeth of the stock mating gear differently. What could be the long term effect of that? Increased gear wear?

.
 
Back
Top