R80RT or R100RT, and why?

[basketcase]

Ever once in a while, I find myself lusting after an RT model airhead. For example, when I see something like the Alps photo on page 57 of the June issue of the ON.

My interests always seems to focus on either the R80, or the R100. I keep thinking, "One of these days, I'll run up on what I want and trade the K model."

Since I've never owned an airhead, I thought I would appeal to the opinion of those on this forum to see what you have, or which you would choose, and why.

Probably, I am the only motorcyclist in the world seized by such episodes of mental duress -- but then, I could as easily be wrong ... :brow

[kbasa]

R100RT.

Mo power is mo betta.

[coyotebmw]

If you do some checking in the ads you will find that the R80RT is harder to find, ever wonder why?

I spent almost a year and a half trying to find my R80RT, they were few and far between. Most were in other parts of the country, so not practical to purchase. When I finally found my bike, I actually found two R80RT's within a couple of weeks. The first one was a very nice looking red bike (84'), but when I looked at it found some damage that the owner "claimed" he knew nothing about. Later found out he had been the one to damage the bike (dropped it and broke the right mirror and damaged the lower fairing on both sides). This person was asking too much for the bike with the damage it had and would not come down to a fair price. A week later found my bike, original owner with complete records and well maintained. Paid his price because it was fair!

Why the R80RT over the R100RT?

I have alway considered the R80RT to be the definitive early 80's airhead for BMW. It was the combination of sport bike and touring bike, the first real sport touring bike! Just the right size for one up touring. But, quite capable of handling those twisty roads most riders love. (if you really wanted to do two up then the R100RT was you bike) In talking to various mechanics and others I have heard that the R80RT is more trouble free than the R100RT as well.

[R80RTJohnny]

Hello Rick,

R80RT or R100RT tough question. I've had my 86 R80RT since 1988. Truly an amazing travelling companion for one up touring up to 75 mph. If, however, you need to go two-up then I would strongly suggest the R100RT.

Please do not get me wrong the R80RT will handle two-up duties quite well but as was said before the more power the better.

Good luck.

Jean

[lkchris]

At any given road speed in the same gear the R80RT will turn 1000 rpm more than the R100RT and return poorer fuel economy and less performance doing so.

Folks should realize that the R80RT and R100RT are the exact same bike except for sizes of cylinders and pistons, and since the R80's are smaller, its carburetors are smaller, too (earlier versions). There is no noticeable weight difference and absolutely no physical size difference.

There's just no reason for the R80RT that I can fathom.

[coyotebmw]

In light of the previous statements, I did a little checking:

1983 R80RT:
Curb Weight = 516 lbs, Wheel base = 57.7 in., Power 50 @ 6500

1983 R100RT:
Curb Weight = 525 lb, Wheel Base = 56.7 Power 70 bhp @ 7250

Runs a 1000 RPM Higher huh? Weight the same Huh?

Data from BMW Twins and Single, by Roy Bacon, and BMW 2-Valve Twins, '70 to '96, Haynes Service and Repair manual.

[basketcase]

The weight difference as cited above is 2%. Not exactly enough to tell it while sitting at a stoplight, or even when (heaven forbid) lifting it off the carport deck.

However, the horsepower difference is nearly 30%. That is interesting -- even to someone as mechanically challenged as I.

Since I am mentioning numbers, I might as well observe that 99% + of my riding is solo. What that means is that about once a year, my wife or one of my kids will ask to go for a ride. So when I one day make a trade, it will be with the solo thing in mind.

The styling on the classic BMW's has always attracted me, and false humility aside, I don't mind doing the tune ups and other routine maintenance.

Thanks for the feedback and food for thought.

[coyotebmw]

I agree, it's the classic style for me as well. I think the big issue here of the R80RT vs. the R100RT is which you like better. I have loved the R80RT since it first was introduced in 1983. It was my dream bike for over twenty years. Being able to finally purchase one to ride was my highlight of last year. While the R80RT and the R100RT are very similar, and the R100 is a larger displacement more powerful version, I still prefer the R80. I think it really comes down to which is the right bike for you.

If you look at the history of BMW I think you will find these two bikes are really a piviotal bike in the evolution of the BMW. The are basically the last, and high point in design, for the Classic BMW. After them BMW saw many changes, K-bikes, 4-valve airheads, even a chain drive single (I am restoring one of the original singles, an R26).

As to the differences between the R80 and R100, I think the R80 was suppose to be the affordable BMW of its time. It was designed to compete with the Japanese and Brit 750 cc bike of that era. While the R100 was designed to compete with the super bikes that the Japanese and Brits were introducting. The beauty was they were better built, more reliable bike than any of its competition, but cost more initially. While the Japanese and Brit bikes were less expensive, their life expectancy was about half that of a BMW. Also, the maintenance cost on those Japanese and Brit bikes was higher over the long haul than the BMW's.

[DonHamblin]

How do you beat "cubic inches" ('er, cc's)?

Don

[R100RS]

What about the RS?

It is truly an amazing fairing offering great wind protection. The RT does offer a much more upright riding position, but I put bar-backs on my RS and find this the best all-around riding position (for me). The RS really was the true airhead sport-touring bike.

Between the two RT's you're talking about, it's a no-brainer in my book. I don't think anyone has ever asked for less power.

[MarkF]

Originally posted by coyotebmw
I have alway considered the R80RT to be the definitive early 80's airhead for BMW. It was the combination of sport bike and touring bike, the first real sport touring bike! Just the right size for one up touring. But, quite capable of handling those twisty roads most riders love. (if you really wanted to do two up then the R100RT was you bike) In talking to various mechanics and others I have heard that the R80RT is more trouble free than the R100RT as well.

I thought the R100RS was the first Sport-Touring bike. I always considered the RT as a full tourer, before the big Luxury Tourers arrived.

MarkF

[MarkF]

Drool!

[coyotebmw]

MarkF, Yes that is a VERY pretty bike! As to the previous comment on the Sport Touring bikes, yes the R100RS is the true sport touring bike, but the RT models of that era were more closely related to Sport Touring than they were to the Full-up Goldwings and Luxury Touring bikes. Even today the R1150RT is more like a Sport Touring bike than the Luxury Touring bikes we see from the other manufacturers.

The big difference between the RT and RS models was the fairing height and size of the windscreen. Otherwise they were very much the same bike. Let's be honest BMW has always built bikes for the riders that like curvy roads, rather than open freeways (except of course the Autoban in Germany).

[MarkF]

Originally posted by coyotebmw
Let's be honest BMW has always built bikes for the riders that like curvy roads, rather than open freeways (except of course the Autoban in Germany).

Lets be honest, BMW always has and still does (to a lesser extent) build one bike (R-bike) with the same motor, tranny, frame, etc. It just hangs on different bodywork for different functions. I miss the days when you could convert from one model to another with relative ease.

MarkF

[basketcase]

Personally, my temperament is more that of an RS rider, but a damaged rotator cuff in my right shoulder keeps me from accepting an aggressive riding posture.

Nice pictures.

[kbasa]

Not sure I agree with you completely there, Mark.

The three oilheads we've owned have all had different transmission, different engine tuning, different exhaust and different final drives. The structure supporting them has all been different too. Tina's R is different than the RS and my S was unlike either of those. The basic engine architecture is the same, but they've been pretty heavily tweaked for their specific mission. There's little parts commonality among those three bikes.

[MarkF]

Originally posted by KBasa
Not sure I agree with you completely there, Mark.



That's why I said to a lesser extent. The motors, trannys are tweaked and the subframes might be a bit different. But strip any oilhead of the same dispacement naked (except the S) and you will see a family resemblance.

MarkF

[rocketman]

If your doing mostly one up riding, then the R80 may be the one to go with. One thing I've noted between my two airheads is that the smaller displacement motor tends to be smoother at speed due I guess to the smaller mass of the pistions, there is a very noticeable differance between my 60 and 100, not sure what the differance would be in 200 cc's as apposed to 400 but it would be worth trying out both if possible.

Also look for pre 80's models (77-78) before they started down sizing the valves and detuning the engines.

RM

[coyotebmw]

Hey, Rocketman. The problem with your statement on pre 1980 R80's is the Forum is about R80RT vs R100RT, both of which are post 1980 bikes. The R80RT was first introduced in 1983.

[R80RTJohnny]

Hello guys,

To add a bit more fuel to the fire so to speak BMW produced two generations of the R80 and R100 RT's. The first being pre-1984 and starting in 1985 the monoshock R80RT then in 1988 the monoshock R100RT (1987 for the R100RS). While there may have been a good deal of hp difference in the first generation the difference after 1988 was minimal (10 hp).

As these machines are getting older it would be better to find a good clean example of either machine then foregoing one over another.

Remember he rides a K11LT so the power from either an R80 or R100 will seem small.

After reading the statement that the R80's turn 1000 rpm higher at any given speed in the same gear all I can say if that is true (and I seriously doubt it as I have ridden both) then I can say is that the R80 is better geared for any road condition. Sorry for metric system but here goes: 3rd gear 3500= 70 kph
5th gear 3750= 100 kph.

Both bikes can and are very fine machines that deserve to be ridden.

Check out the latest edition of the BMW ON for a story about Mathilda (an R80RT in the alps).

Jean

[lkchris]

Originally posted by rocketman
Also look for pre 80's models (77-78) before they started down sizing the valves and detuning the engines.

Nah, then you have to live with iron cylinders, poor brakes, a really stiff clutch, and shifting reminiscent of farm equipment.

The major detuning occurred with the '88-on R100s.

[lkchris]

Originally posted by R80RTJohnny
After reading the statement that the R80's turn 1000 rpm higher at any given speed in the same gear all I can say if that is true (and I seriously doubt it as I have ridden both) ...

The gearing difference became less on the later (monoshock) versions.

[lkchris]

Originally posted by coyotebmw
In light of the previous statements, I did a little checking:

1983 R80RT:
Curb Weight = 516 lbs, Wheel base = 57.7 in., Power 50 @ 6500

1983 R100RT:
Curb Weight = 525 lb, Wheel Base = 56.7 Power 70 bhp @ 7250

Runs a 1000 RPM Higher huh? Weight the same Huh?

Data from BMW Twins and Single, by Roy Bacon, and BMW 2-Valve Twins, '70 to '96, Haynes Service and Repair manual.

The wheelbase figures are incorrect.

Nothing in your figures describes gearing, which causes the faster running engine. The R80RT has 3.36-1 axle ratio while R100RT has 2.91-1 ratio. The transmissions are identical.

Nine pounds, huh! Gee, if you install the gauges omitted on the R80RT, it will be down to maybe seven! And, if you replace the R100RT's Nivomat shocks with the R80RT's plain shocks, ... . And perhaps (my memory may be incorrect) the R100RT had saddlebags as standard equipment and the R80RT didn't.

For accurate statistics, view

R100RT (http://www.bmw-motorrad.com/com/en/index_frameset.html?content=http://www.bmw-motorrad.com/com/en/fascination/history/models/bmw_r100_rt_data.html)

and

R80RT (http://www.bmw-motorrad.com/com/en/index_frameset.html?content=http://www.bmw-motorrad.com/com/en/fascination/history/models/bmw_r80rt_data.html)

[coyotebmw]

Thank you for the link to the excellent site. I have been looking for acurate data on my bike. It is interesting that the offical site a) shows the R80RT with saddle bags, b) states that the R80RT has only a single disk front brake (I know I have dual disk on my 83' R80RT, since I just replaced them).

Also, when I was looking to replace tires on the bike last year. Most sites showed the R80RT as having 18 inch front and rear tires. This site shows 19" front and 18" rear, which is what my bike has.

I explored the site some and found it a gold mine for someone who is interested in the history of BMW. Thank you, again.

[dlearl476]

Originally posted by Don Hamblin
How do you beat "cubic inches" ('er, cc's)?

Don

Or, as a friend countered when I was explaining why I prefered the K75 to the K100, "Hell, my first four bikes had 150CCs, or LESS!"

These bikes were my first two "grown up" Beemers. I still have my first R60/5, but while I was on the road and missing it, I rented a R80RT from Frank down in Phoenix, and the experience led me to purchase a R100RT later that year. IMHO, the R80 was smoother and felt a little lighter and consequently more nimble. But then I prefer the mid-size bikes. (See above) If two-up and lots of touring was your goal, I'd say the 100, but since it's not, either would be nice.