Hi Folks

I am new to Beemer bikes and there are 3 bikes advertised.

All are k100 but what is the difference between an RT, RS and LT.

I am unlikely to be travelling long distances (over 200km) at a time but need some comfort with the performance.

Old (64) biker with a few loose joints.

Ta

Hutchie

Hutchie, welcome to the forum.An RS is supposed to be the sportier bike, small fairing, small windscreen, no panniers etc. The Rt came originally as the road tourer, bigger screen, full fairing and panniers. At a later stage the RT was renamed as Lt...Luxury tourer and had a few more changes. Originally the K100 had 8 valves and this was upgraded to a more powerful 16 valve version.

Check the vins and the month, year of manufacture, this will tell you whether it is an 8 valve or 16.

I have loose joints but not loose bowels...yet. Consider the various weights of bikes as well, as the more equiped the bike is, the heavier it gets. As an example a naked K100, like mine weights in at about 260 kilos with fuel. If you want to see what that version looks like go to general discussion, how old is old.

hi hutchie.....welcome to the forum

ok the RS is the first to be recognised as a formidable and classic design with a smallish screen on the fairing in front and a slightly leaning forward position of the rider (handle bars only lift abour 2 inches off the steering head )

almost all the other components except for fairing, pad at the steering head and bar lift are similar across the models , and a slightly lower differential ratio .(goes faster /rev) and a slightly tighter front springing solution on 85- on models

RT has a much taller and wider fairing , handle bars have a lift of about 8 inches ....the pad at the steering head has position for 4 switches
a more upright ride in all .



LT is verry similar to the RT in all respects but has a different fittoff of the inside fairing accessories ...many have instruments etc at about 10 inches higher than the steering head in the fairing along the line of or just above the base of the windscreen radio fitt off options etc

not sure exactly, but you wont find a LT before about 1985-86

a big design change happened about 91 when wider rims and a paralever (2 joints in the tailshaft) type diferential were introduced , along with a 4 valve per cylinder motor was released


dont forget these babys are heavy ...and for those that are inseam challenged (short legs) they present an issue mostly when stationary

if this is the case, look for models that have a lowered seat



but generally they all ride beutifully and purr up the road



my 10 cents worth

Ive got both an RS and RT, and find the RS more 'fun', and more my 'go to' bike when in town, heading for a cuppa (see Darren, KFreak, and Charlie, I remember somethin'). But if I'm hitting highway speeds more regularly I take the RT because of better wind protection (and then there's the R1150RT that hasn't even been out this year!)

Hi Ya hutchie Welcome to the forum.

The RS is a Road Sports with a bit of tourer The RT is a Road Tourer with a bit of sports The LT was introduces around 1987 and is the Luxury Tourer and the main upgrade was a standard Comfort seat which was an enormouse improvement over the Ironing Board type on the others.

The RT & LT had the wider and higher fairing. The RS from 89 on had the 16 valve engine and wider rims to take the radial construction tyres.

Don't forget to keep the shiny side up.

Hi Hutchie welcome mate, I am sure you will enjoy whatever varient you buy, but charlie is right they are heavy.

my retired ex work mate has a 75RT and has had to have a lower seat and shock fitted, mind you he is virticaly challenged



BIG D

Thats a great explanation guys. Thanks.

I am 5ft 8" tall and about 11 stone, the weight is a concern.

At present I am about to turn 64, fit and want a bike that I will be able to handle for some years. Recently sold my CB750 and the weight was OK.

No problems on the road but at some point I will probably want to get off!

I had better go and ride one.

My K100 in this avatar is for sale Free Plug

RS is lighter and quicker. Less weight.-equals a little more speed, the upgrade in the valves gave it more horse power, and a little smoother engine. Less protection from the elements

It seems by all reports the difference between the three models can best be measured by the amount covered up in acres of plastic ware. I ride my RS every day in rain, wind and shine. It offers very good weather protection. The RT and LT of course will provide even greater protection and generally a more relaxed riding position but the trade off is additional heat. Did I read North Queensland? That is something to consider, and there are many good ways of reducing the amount of heat you'll feel coming at you from the engine and behind the plastic. All models can be reduced in ride height without sacrificing too much of their easy handling quality by 'dropping' the forks up in the triple clamps and getting a shorter shockie out the back, with various low seat options available too. The RS has an overall 'taller' final drive ratio than the other two models, but most of the other niggly mechanical details are the same between the three.

They are big girls, but, and if your inseam is under about 82cm (32") it's a stretch to the ground. The RS also has narrower and lower 'bars and if the reach is a problem you can add 22mm diametre/25mm higher 'risers' to help with that problem as I have done. I have also 'widened' my 'bars for more leverage by inserting a double-screw-together-thingy inside the bars that replicates the outer diametre so the grips are further out than stock. I rode for nine weeks straight round the edge of OZ last year with nary a backache or overly sore bum at day's end.

BTW, the 16 valve engines weren't added until the late '80s with the K1, then the K100, followed by the further upgraded K1100. Prior to that all four cylinder models had 8 valves.


RS

RT

LT

"All are k100 but what is the difference between an RT, RS and LT."



The RS is better...

Being one of the newbies here...I found this wonderful description of the differences of the RS RT and LT K bikes..Just what I needed to read...even resurrected an old thread... Thankyou all!

Guys this is a good thread. A question though, I am looking to buy a 1987 K100 to turn into a really nice high quality cafe racer build. The bike that I have found is the LT model, I understand that this has all of the extra fairing etc etc - which I won't be needing. My question is with the 3 different models, if you stripped them down to just forks, frame and swingarm is there then any difference between them? This will really help me decide which model I should be looking to get.

Cheers in advance guys

Paul

Very handy site for working out whether a bike is suitable. You can put in your personal measurements and go through all the Bricks and other brands.http://cycle-ergo.com/
Regards Martin.

Paul75 wrote:Guys this is a good thread. A question though, I am looking to buy an R100 to turn into a really nice high quality cafe racer build. The bike that I have found is the LT model, I understand that this has all of the extra fairing etc etc - which I won't be needing. My question is with the 3 different models, if you stripped them down to just forks, frame and swingarm is there then any difference between them? This will really help me decide which model I should be looking to get.

Cheers in advance guys

Paul

Up to 89 mechanically almost identical, 2 valve engines, one little difference being the final drive ratio on RT/LT are the same but the RS was geared a little higher. Engine performance and tuning identical although there are stories about early camshafts being 'hotter' and my 84RT always felt more perky that my 92LT.....

Exhausts, handlebars, clutch, choke and throttle cables, ignition impact pad differ. Also various wiring changes and upgrades that affect using parts from different years. Forks also changed over time and again early/later ones vary as to how you may interchange them. I have a feeling RS ones may have been a little different.

ABS was added to RS and LT, its not designed to be retrofitted and quite a few parts differ too. Engine power output is same across all 2 valve engines. The only really simple option is putting K75 pistons into a K100 as they are higher compression ratio and a straight fit.

89 for model year 90 the RS became 16 valve and upped from 90 to 100bhp and with completely different ignition system. The K100LT remained 2 valve and 90 bhp with added accessories.

But things like ancillaries water/oil pump, starter, alternators are interchangeable between both engine types but the usual modifications that happen during the life of a particular model mean be careful of year of manufacture.

The ideal candidate is a K that's suffered badly in the cosmetic side of plastics etc but its reasonably good mechanically.

Thanks that's great info. I should of said it is a 1987 that I'm looking at so was wondering about the difference between the 3 just for that year but I think you answered all my questions anyway. I really was just checking that the 'stance' of the bikes side by side, just bare, wheels, frame, swingarm was the same and I think they are......

If I have said anything misleading someone will correct it......but I do have one of each here.

Besides the final drive ratios, I think that there may have been different forks used on the different models with different travel, and possibly different spring rates and damping.  I'm not sure if it was just from year to year or different models in the same year. 

BMW got forks from two sources, Fichtel & Sachs and Showa.  Judging from the section on front suspension in most manuals there are many internal differences between forks, even from the same manufacturer. 

I know that my '94 K75RT and '94 K75S have different amounts of travel and that the forks on my '92 K100RS use a different amount of fork oil.  Not sure if any of it makes a difference to a cafe build as most of those seem to be styling rather than performance exercises.

Just put a set of girder forks it would not make any difference they only get ridden to the next cafe to show off.

We are all getting older, lord knows what the average age of a K rider is but I recon a good percentage on here are over 50.

Anyway, as I have aged I have made the 86 RS more comfortable. RT handlebars, comfort seat, lowered the rear and lifted the triple clamps to the highest setting. 

I am in Western Australia so it is hot. I have removed most of my fairings.

The bike still looks timeless, goes as hard and reliably as it always has and is as comfortable as a favourite old armchair.

You cant go wrong with a K Paul, even the sporty one can be made to suit most shapes and sizes of rider using factory parts! (except my rear shock is from a Kwaka, we wont dwell on that)

I own a 1985 K100RS and an RT. The RS has quite a bit more spunk. Same engine but different gearing. It also is taller and requires a taller rider and wind protection stops below chin. RT is a bit slower, gearing is, for some reason, not as tall, but it provides more wind protection. My favorite is the RS.

I own both RT and RS models. You are correct about the gearing. I suspect it is meant to provide more pull on hills with a heavily loaded, 2 up touring bike on the RT, while allowing a higher top speed on the RS which is probably meant to spend most of it's time 1 up and lightly loaded.

Both models share the same frame and geometry, the major difference is the RT/LT models weigh a bit more and have slightly different weight distribution. The riding position and wind protection is different as well. The RT/LT is really better for long days in the saddle eating a lot of miles comfortably. The RS is more fun to ride, but can get a little uncomfortable after 5-6 hours, especially if it's cold and raining.

I added a $20 wind deflector on top of the RS fairing. It makes quite a difference but still less protection than on an RT. But if I lay flat at high speeds I can avoid being hit by strong headwinds.
PS: This post was misplaced. It should have appeared under a different topic. Apologies!

I have all three......84 RT/ 92 LT best weather protection out there. But I love the 83 RS.

RT/LT 32/11 final drive, RS 31/11 final drive.

Battlax BT45/46 on them all, 38psi front 42psi rear.

Have K1100LT too, but the old RS sounds the least busy of all and being the very early K is definitely the liveliest despite 2v engine.