The ST really isn't a long distance freeway eater, but that kind of riding is a pain in the ass regardless of what you ride. As you have seen they are great for narrow twisty roads - the gearing and f/d ratio are well matched for just such roads. I've put a taller fifth in mine mostly so that I can not be right at redline while on the unavoidable sections of highway between the fun roads. Of course in the US west I prefer to ride my RS.....
I'm spinning 5k at 80mph. I ride freeway a lot, unfortunately, in Atlanta which is kind of like playing frogger. STock box and FD, bike does very well in my opinion.
Hmmm... that's pretty much what my girl does, I guess I'm just averse to much over 4000 rpm sustained . I like revs on the hills and twisties but not for hours at a time .... no good reason .
Really interesting ideas, my ST has a 100GS tank and for long trips on the tar it's great but the weight is too high on the dirt or moving very slowly. Thinking, thinking .
Sorry, I don't know yet. I bolted up the neg. cable for the first time yesterday to see if all the electrics work. The Eastern Beaver headlight relay kit worked well and the starter engaged, but sadly the turn signal relay seems to have bit the dust. Like you suggested I don't expect the 5% taller gear to be a great change - just something I could do while I had the box apart and with the lower ratio of the f/d I can't imagine it'll put much more strain on anything. Airhead engines run just fine for hours on end at the upper rev. limits though so don't worry about that.
Actually these bikes are designed to run between 4-6k on a continuous basis...normally I run mine between 4-5k. 4K is suggested as a minimum RPM for normal use. Howard
The 4k normal RPM range is based on 3k required for full alternator operation and 4k is suggested as not to "lug" the engine and to give full oiling to things like the valve train and timing chain. This figure has been highly debated on the "Airheads" list server and supported by some of the American "gurus" like Oak, Snobum and Cutter, two of those I know personally and one who has been a houseguest of ours. Howard
OK, good to know although I usually bumble along at between 3000 and 4000, I'll try to overcome my prejudice against high revs !
Anton has a good gear ratio chart, you can play with different rear end and gear combinations to find theoretical rpm's at speed... Per his chart, the standard ST with a 37/11 (3.36) rear end, at 5000 rpm in fifth you are doing approx 75mph.
My results agree with what Bob just posted from Anton's info. My tach starts to get erratic when cruising at anything over about 5200 for more than a couple of minutes. But during my slogs up I-95 to get out of Flatistan and onto regular hiways I'm matching most car traffic at 5K rpm. And experience has shown that most traffic on that stretch runs at about 74-75 mph.
The one thing to remember with that is that it assumes a 6.6 foot wheel circumference. I'm not sure what the circumference of the 18" ST rear wheel is. Anyone care to wrap a measuring tape around?
...which is exactly what I happen to have on my back wheel at the moment. 82/79 = 1.0379 so add 3.8% to those speeds for our wheels.
Something drifted through my brain this morning about wheel circumference - I have a faint recollection that rolling circumference may be different than static measurements due to the slight reduction in radius at the contact patch as the tire deforms ever so slightly from the load on it. May be hogwash, or something I dreamed. If the rain showers will hold off for a little while I will roll the ST out and pick up the actual rolling circumference with my weight on the bike.
Unless Avon specifies, I would expect their numbers to be a static measurement. News Flash! Did the rolling circumference a little while ago and got...... 6' 7" or 79". :huh So we're back to 79/79, or Anton's tables are on target. I suspect most of the discrepancy in my first static measurement could be a combination of stretch in the cotton rope I used around the wheel, any extra length from "wiggles" as the rope may have aligned with some tread blocks, and lastly any actual variation in effective tire radius when the bike is loaded sitting on the pavement.
