High top gear trans

[trickytree]

There's a gearbox for sale near to me with the overdrive top gear, thinking about it to reduce the revs on long journeys. Has anybody managed to compare the two?

[Buckster]

I haven't compared the two but I have the taller geared sixth and it will lower the revs. The only problem is that if you are not doing close to 75 MPH in sixth, you are at the point of lugging the engine. Not sure what that would be in KPH but it is surely over the speed limit here.

[sweatmark]

There's a gearbox for sale near to me with the overdrive top gear, thinking about it to reduce the revs on long journeys. Has anybody managed to compare the two?

Owned both Roadster and Rockster, with overlap of several years. The 6th gear in Roadster transmission is great for highway travel, and I still look for it subconsciously after riding Rockster for almost ten years, toeing the shifter and finding a dead end. I would happily swap the top gear ratio as better fit for current Rockster use: 1000+ mile trips.

My plan B - should I ever have final drive bearing problem - is to change the Rockster's final drive ratio for taller gear set. This will lower RPM for all gears, at the cost of decreased rear wheel thrust (torque X radius) and slower acceleration. Perhaps too high a price for interstate/highway mellow.

[trickytree]

Thanks chaps....dilemma sorted anyhow as I forgot about the auction and the box sold this afternoon!

Agree about always looking for another gear on the Rockster. Don't want to raise the gearing at the bevel box as to high a first would be a bit awkward on hairpins, (especially as I'm taking Mrs.tree to the Alps this summer).
It's not a problem most of the time, on the real minor roads I rarely use 6th anyway, but when I do at least I don't have to worry about changing down for a quick overtake....great pick up in top.
Perhaps there's a place for a aftermarket 7 speed box!

[vwdoctor]

I had a chance to ride R1150R before the Rockster and it had the tall 6th gear. I didn't like the transition between 5th and 6th, too much of a gap. I am not sure if it makes any difference on the fuel economy, but to me it wasn't "fluid" enough.

[sweatmark]

I had a chance to ride R1150R before the Rockster and it had the tall 6th gear. I didn't like the transition between 5th and 6th, too much of a gap. I am not sure if it makes any difference on the fuel economy, but to me it wasn't "fluid" enough.

Certainly true: the shift into that tall 6th gear is a big jump, the rider's declaration of "Interstate travel mode selected, dammit! Time for scenery and eventual butt cramp." And while I wouldn't want such abrupt RPM change at either end of a track day straightaway, the sensation is mentally and vibrationally comforting, a sedate equivalent to Mad Max pulling supercharger drive-pulley engagement knob on his Aussie V-8.

[trickytree]

......... a sedate equivalent to Mad Max pulling supercharger drive-pulley engagement knob on his Aussie V-8.

Hey, I'm sold

[peels]

I cant "compare" them. but I can say, I like the overdrive. The only down side, is that it makes 5th feel VERY low, so I end up unnecessarily searching gears to avoid lugging.

aside from that, 8+hrs on the slab, its almost perfect. nice happy diminished vibe spot at 80-85mph.

if 5th were maybe 3-400 less rpm at 65-70 mph, it would be FLAWLESS.

[sjbmw]

The gear is useful at 75mph or better. Incredibly useful! It will sit dormant for daily sprints....
IMHO, it was made for US highways.
It was removed as standard component after the 2004 models. It was an "option" in 2005.

[kirby]

I think the standard r1150r (the majority) .8 top gear where the rocksters will most likely have a .7 top. This will make about 400 rpm difference.
My rock is at 4400 at 80 mph indicated on the speedo. My r will make 80 at 4000.
I have seen no real diff in mileage between the two.(mid 40's) but the rock will leave the r for dead on top gear roll ons.

I have over 200K on my rock and I much prefer the .7 ratio. (the r1150r is an '02)

[trickytree]

The Rocksters top gear is certainly usable, no need to change down for quick overtakes just see a gap and go for it, even 2 up its still a usable ratio.
Just been out today actually, nice crisp sunny winters day and dry roads as well.....to good an oportunity to turn down!

[kirby]

As a comparison on high top gears I ride sometime cross country with a good friend that has a '09 road king HD, 6 speed full dresser. He gets better fuel mileage in 5 gear when we are running at 80 on the slab (freeway). If he goes to 6th at 80 it won't pull along hill at 80 so has to go back to 5th.
He hates it! So we are going to change the sprockets to a lower ratio, an expensive mod but should improve his mileage 'cause he will be able to run in 6th.