5 or 6 Speed, Close Ratio 4 speed

hi all on the forum, would appreciate some feed back on close ratio 4 speed, 5 & 6 speed gearboxes. Part of my thoughts for Bike #2
Have been speaking to TTI as they are made in NZ, just some thoughts from here please
Regards Mike

I'm trying to figure out the same issue. All's I can go by is conflicting: pleasure of not dropping rpm's enough for good upper power band to gain 10-15 more mph quick enough not to loose ground to new sports bikes; or the annoyance to peddle two extra gear shifts just getting around with legal-ish thrills. Do note in lower gear ratios there is more engine let off drag on tire so more hazard to let off and wipe out on rear chriping off surface. 750 1st and 850 2nd ratios worked well to almost 90 for Peel but would of liked an extra 2 gear ratios to stay on top of 2S cam before 4th, which pulled just fine for me.

My 750 Norton ultra short stroke (75mm stroke) started with a Nourish five speed. This used the stock Triumph T140 internals. When looking to upgrade to a TTI box the rider at the time, Rob McLendon, said go six speed as "he could use the gears". And man does he.

For me, right now, a six speed is very busy on the track and probably hurts my lap time. I am becoming a bit of an old fart on the track where I have had far too little quality track time in the last few years. I am sure I could make the six speed work for me with time but there are far too many greater improvements to be made (ex rider skills).

The 500 Norton ultra short stroke twin needs the six speed.

I had the opportunity (and honor) to run one of Herb Becker's long (stock) stroke Commando race bikes at Grattan a few years ago. This had a Commando box with a close ratio four speed. What a pure pleasure to race!. The track is tight and technical with a +1,300 ft straight. It was finely tuned and finely carburated. Once launched I recall using only third and fourth for the race. It allowed me to focus on setting up for corners, corner speed and exit speed.

Hopefully Kenny Cummings can chime in here. He runs a long (stock) stroke Norton twin. I had recommended that he go with a five speed for his bike. He can give you some perspective. I don't know what his preference is at this point.

A lot has to do with the bike, rider, engine power and torque characteristics and types of tracks you are faced with. One crude advantage of more gears is that it is more forgiving if you have overall gearing errors.

For those who are analytical, there was a text by maybe Tony Foale which outlined the mapping of the torque/thrust curves to decide on the best gear box ratios. I seem to recall it was plotted within an envelope of wind resistance to factor in high speed gear jumps. Neat stuff if you have the data to work with.

I hope you get much feedback on this as it really needs to be placed into your context.

I built my Seeley Commando 850 in 1978, and because I never believed in it, did not race it until 2002. The first time I raced it, it was fitted with the standard box. It was revolting t o ride. Every down-shift required a heap of revs, and nothing was ever smooth. I bought a very close ratio 4 speed cluster out of the US. First gear was higher than a manx's ratio. The bike was perfect everywhere around Winton Raceway, except off the line. I got one good start, and turned under several 1100cc CB750 Hondas, on turn two, but the bike popped a fuel line and pissed alcohol all over the motor. It showed me that the bike has the potential to do what is required for Period 4 historic racing, so I bought the six speed TTI box. First gear was ordered so that it was halfway between standard commando, and manx ratio. I haven't tried it yet, that should happen at our ride day at Winton on 25th August 2012.
With the 4 speed CR box, the motor spins up extremely quickly even though I run very high overall gearing. I've set the motor up to pull like a train,but it's very difficult not to over rev the bike past 7,500 revs, even if you aim for 7000 rpm. The bike was impossible off the line in a clutch start, but once it is going, it is really gem everywhere else around Winton. What is really good about the CR boxes, is that if you need to duck under someone in the twisty stuff, you can snick it down a gear, and get heaps of go just when you need it, there is no lag. They turn a shit heap into a brilliant bike.
I sold a really good TZ350 G Yamaha to buy the TTI six speed box. - (I made a choice).
There are people who say that if you've got a torquey motor you don't need a CR box - that is bullshit. If you are building a racer, always start at the gearbox, it permits you to go radical elsewhere, and makes a low performance bike better anyway.

I just installed a TT Industries gearbox on my 750 Commando racebike. Great gearbox but remember -racebikes are bump and roll or roller started. The TT gearbox does not have a kickstarter on it. :shock: You would have to have an electric start for street use.

Tom Kullen
AHRMA 44x
Formula 750/BEARS
Event Coordinator
Bonneville Vintage GP
http://www.bonnevillevintagegp.com
tom@bonnevillevintagegp.com

Hello Tom,

We don't know what Mike's intentions are but TTI does make a kick start for some of their boxes. I have a five speed extra heavy duty TTI for the 1,007cc Norton Seeley Gulp Monster specified and received with a kick start. Now all we need is the big galoot to kick it over.

Bruce Verdon of TTI is also working on some neat packages such as gear box innards for a Triumph/BSA Triple (five, maybe six speed). He showed me one at Barber last year. I seem to recall he was making it to accomodate a couple of different clutch hub options.

Always good to chat it up with him now and then to see what he is up to.

hi guys, thanks for all the excellent feed back and yes Dances, Bruce has quoted me for a kick start gearbox which does add a lot to the price.
Will let you know when I have made a decision on it all, keep it coming!!
Regards Mike

Mike,

Share with us what your intentions are for the subject bike #2.

hey Dances , yes compiling pics as I do, just not at home right now to make progress, so over the next few weeks you will see the posts start.
Took a bunch of pics of the strip down and issues, motor still in the frame, that will come out and be stripped by next weekend.
Talking to Ken mcIntosh in Auckland NZ as well about gearbox bits, here is his link for those who maybe interested and not know of him.


http://www.manxnorton.co.nz/catalogue/c ... =1&c_id=34

Also where I am at work makes it difficult to upload pics because of the band width, some times takes a while for a thread to download off the forum if there are pics attached. Will be home next week and will start a thread for it.
Regards Mike

My experiences with gearboxes in performance situations started with a stock Commando 4-speed box on my first race bike. I didn't know any different, and rode around for a couple of years picking up speed and working on my race-craft. Then I was allowed to practice on a buddy's bike with a 5-speed box, and it broke my world wide open. In fact, this guy sold me this gearbox (Quaife) so he could buy a TTI box. My first time out with the Quaife on my own bike was eye-opening. it felt like I had a turbo boost when shifting into 3rd and 4th. I'd never before experienced keeping a motor in the power like that. The Quaife did have an overly-tall 1st gear (IOM style), which was not necessary for me as I never shift down to 1st in any race after my launch. I ran the Quaife for 2 seasons, but after sitting out of race weekends a couple of times with broken gears, I decided to sell it and put the money towards a TT box. I conferred with Mr. Shrapnel at the time, as he had a TT box on his 750 Short Stroke. And after long discussions with Bruce Verdon (a Hell of a guy, by the way) at TT Industries, we put together a really good box with the proper ratios to suit our races here in the US - short circuit, 8-10 laps. My first gear is just a little taller than a stock street Commando - great for launching, and the other ratios are nicely matched all the way up to 5. These boxes are bullet-proof, and shift so smooth, I actually had to put more pressure on the detent as it was too easy.

I have the luxury of running a Summerfield Manx and Seeley G50 on occasions, and they both have 6-speed TTI (Or Hemmings/Quaife drum-style) boxes, which are better suited to the way these bikes are ridden. Personally, with all the torque the conventional stroke Commando has, I would stay with the 5-speed if I had to buy another. Now if I had a tightly wound 750 short-stroke, perhaps a 6 would be the way, as Mr. Shrapnel has opined.

I have since raced bikes with stock street boxes on them, and I have to say, I've been spoiled. The downshifting on a street box in a race is so difficult, as every shift spins the motor so high, locks the rear wheel, and the duration it takes get down a couple of gears is a lap-time killer.

And finally, if I had the option, I would love to put a 4-speed close ratio cluster on a street bike. I know RGM has this option. That would be the best way to out-wring those corner cripples, Stevie Hobot.

Holmeslice said:

corner cripples,

Click to expand...

Somehow I think this thread is going to degrade quickly

Good take from the Holmeslice and glad he is satisfied with the five speed for his fine steed.

Good stuff.

Dances with Shrapnel said:

Holmeslice said:

corner cripples,

Click to expand...

Somehow I think this thread is going to degrade quickly

Click to expand...

I'm laughing out loud...

Get and eye/earful of a very nice Commando being spun up. I only went up to 4th in this video, but it does have a 5-speed close ratio.

http://www.youtube.com/watch?v=dDdwSMV0 ... e=youtu.be

Thanks Ken, excellent stuff and just what I needed from you all on the forum to go for the 5 speed initially, and then go with a TTI box,(once I save up) as I can then use the 5 speed down the track for my Roadster .
Just to say that I did notice how awkward it felt with the std 4 speed on my track day recently, even found a false neutral between 2 nd & 3rd acouple of times after changing down from 4th coming into the same corner.
I have ridden plenty of bikes (both on and offroad)with 5 and 6 speeds in the long interim period from being raised on Brit bikes ,mostly Nortons, in the 70's until getting back into them now, so really can appreciate the need for an extra gear or closer ratio's to keep the revs up on the track.
Regards Mike

And finally, if I had the option, I would love to put a 4-speed close ratio cluster on a street bike. I know RGM has this option. That would be the best way to out-wring those corner cripples, Stevie Hobot.

Click to expand...

If discussing every other bike on the planet then I'd follow the proven wisdom expressed above. I listen close to throttle and rpms in the race video of vintage and modern entering turns. Ms Peel should get around best with the widest 4 spd ratio's using lowest Ist I can fit, a tall 2nd, close to 2nd 3rd, then big jump to 4th. !st for trails and parking lot stunts, 2nd and 3rd not to lug on low throttle legalistic use and 4th for clutch dump standing starts and twisty track type play. Pipe dream till saved up extra for ITT kick option. Just imagine the conversation Bruce Verdon will have concerning Peel someday. May end up with a side car version with reverse.

Hi Mike,
what track were you running at? I haven't taken mine out on the track as its 40 years old and parts are expensive....unlike the BMW I built up that I thrash past its 7500 redline.....
I have pre unit Triumph project that I have been collecting bits for, and have a T140 5 speed cluster to go in the pre unit box, probably up for a grand doing it that way.....what are the TT boxes worth...
Are you coming up to Hampton Downs for the Barry Sheen Memorial over Labour weekend?
What is it your building....a pre 76 to race?

Quote; By hobit Wed Jul 25, 2012 1:17 pm
I'm trying to figure out the same issue. All's I can go by is conflicting: pleasure of not dropping rpm's enough for good upper power band to gain 10-15 more mph quick enough not to loose ground to new sports bikes; or the annoyance to peddle two extra gear shifts just getting around with legal-ish thrills. Do note in lower gear ratios there is more engine let off drag on tire so more hazard to let off and wipe out on rear chirping off surface. 750 1st and 850 2nd ratios worked well to almost 90 for Peel but would have liked an extra 2 gear ratios to stay on top of 2S cam before 4th, which pulled just fine for me.

Quote; By Dances with Shrapnel Wed Jul 25, 2012 1:25 pm
My 750 Norton ultra short stroke (75mm stroke) started with a Nourish five speed. This used the stock Triumph T140 internals. When looking to upgrade to a TTI box the rider at the time, Rob McLendon, said go six speed as "he could use the gears". And man does he.

For me, right now, a six speed is very busy on the track and probably hurts my lap time. I am becoming a bit of an old fart on the track where I have had far too little quality track time in the last few years. I am sure I could make the six speed work for me with time but there are far too many greater improvements to be made (ex rider skills).

The 500 Norton ultra short stroke twin needs the six speeds. quote.


There is no hard and fast rule for 4,5 and 6 speeds really, as each has their own merit, depending on whether you are asking about racetrack use or public road use.
Paul Dunstall on the spineframe 750 Dommiracer found that 5 speeds gave a slower lap speed at Brands Hatch but may have used 5 speeds on other circuits.
As for road use, the crux of the matter is that most manufactures use 6 speeds and over gear on top gear because they use it for an overdrive, which some riders simply hate.

For me it is the rather high wear factor on a stock box, the extra gear
really isnt required. TTI will make you a four five for six I believe.
Since I come from the Trident side of the family, I went with a five
which is handy if you haul a passenger at times.
I am talking about a road bike here not a track bike.

My quandry is maxing out my life and times on Commandos with least excess spending in semi retirement from job and world at large. Its takes so much to really fix up a Commando based cycle to keep up with Triumphs and not blow up,its counter productive for me to even think about upgrading on plain street bike as just tempts me to tear it up or crash going too fast into bad conditions here.

Peel is a dilemma as don't fit no road race classes d/t cheater power adders and must earn her keep as main transport when ever practical. Yet her main reason for me is to surprise everyone by her performance envelop. i'm not that secure a fast rider on other bikes but Peel is so freaking easy to control-predict she lead me directly into spin out trip downs and short harsh jerking slides in public tights. I could only do this if power band to spare, ie: snick down a gear or two where everyone else was hard on brakes, while testing throttle traction to point any off center lean instantly lost rear so that was used to lean, then picking back up got traction again in a straight shot, till next trip out point. if I ran out of power to have digital traction then would high side way too much. This action has been reported in this post and others with mis-behavior of hi side antics on power cuts or shift points. If six speed can take Peels power hits then that would be best for her wide scope of operation, but not in same way its needed for lessor power steeds, IE: select gear for safe rpm rather than need of ratio to over power tire. For normal commutes I'd just skip over 1st and 3rd to 5th, to snick overdrive level ratio to cruise on. Also I'm not teasing about putting on a side car, to add to my restless spending spries to come.

If they had easy to fit infinite ratio tranny that's the way I'd take Peel then hold in best torque band by educated throttle hand while skewing the ratio by clutch lever or LH twist grip for the conditions. Off to behave self on nothing special Trixie.

Hi 72 Combat , did the last track day with Moto TT in Taupo with my Roadster, Bike #1, only old Brit bike there, although a guy from Taupo turned up with a Unity Spares Triton he had just imported, but couldn't get it to run right.
Path for Bike #2 is cafe racer style, maybe not road registered, for track days with a view to race in some class at some stage, maybe it will need a better pilot than me to get the best out of it, although it won't be for the lack of trying!!!
Regards Mike