Gbox sprocket for Aus conditions

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Connie73

Connie73

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Jan 27, 2015
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Hi all,


I am looking to replace gbox sprocket, chain and final drive sprocket in the near future. Will be changing the 19t out to atleast a 21t but am wondering if a 22t or even 23t would work ok. Noting that in australia hwy speeds are up around the 100km/h mark im not keen on having the old girl run to high in the rev range for extended periods, not that i do much hwy work. The old boy runs a 21t sprocket on his atlas and it pulls no worries. Has anyone played around with this in aus? Thoughts from anyone would be awesome. This will be going on a 750 commie to if anyone wondered.

Regards
Connie
 
Ho Connie.
SAus based. 22 or 23 teeth improves top speed but make for poor acceleration around town (more likely to stall at lights without a lot more throttle). 21t may be a better choice to balance occassional highway with mostly metro running (19t gives great take-off from the lights but even 80kpm sounds over revving).
Ta.
 
100 kph = ~62-63 mph is lazy=dasy Commando sightseeing speed even in our curvy up-dn area where 65-70 most common. I liked a 20T for ~5% lowering of rpms yet still easy pulled steep long climbs - keeping in mind Norton are healthest in 2500-5500 range. Actually made the Commando torque more usable to me as could stay in a lower gears a bit longer for zoom ups to pass or just for fun. My Peel was almost 22T with belt drive which allowed hanging with the sports bikes almost no matter how fast they dared but was rather more of a launch-leap commitment engaging 1st to take off on un-paved rough surfaces is all.
 
Cheers, needing and hobot.


Will most likely be going to 21t, just wondered if anyone had put on a bigger gbox sprocket than that.

Regards
Connie
 
I have a 22T sprocket that could be had for cheap. I used it for a short time but it required too much clutch slippage for in-town use. On an open road it was no problem.
 
Connie73 said:
Hi all,


I am looking to replace gbox sprocket, chain and final drive sprocket in the near future. Will be changing the 19t out to atleast a 21t but am wondering if a 22t or even 23t would work ok. Noting that in australia hwy speeds are up around the 100km/h mark im not keen on having the old girl run to high in the rev range

Regards
Connie
Click to expand...

Hi Connie,

19t for around town. I run 21t on a 750 but mainly touring (Snowy Mountains type stuff). I would not go more as they can labour in top gear. We had a 24t on a stock 850 and into a strong head wind we would have to change between 3rd and 4th on slight inclines. It also regularly busted gearboxes with a 24t.

Cheers
 
Hi hobot. Now I know you are joking when you state "...My Peel was almost 22T ..." as as tooth count as integers. I plead agnostic but will need to see a photo of an "...almost 22T..." cog to believe in this one.
Ta.
 
Peel had 21T with taller 2:1 primary and taller thick block tire and only pulled to 6000 in 4th for mid 50 mpg 70 mph. Only one way to find out what ya like for long term. Next Peel starts with a 17T to see what that's like.
 
hobot said:
Peel had 21T with taller 2:1 primary and taller thick block tire and only pulled to 6000 in 4th for mid 50 mpg 70 mph. Only one way to find out what

Aha! You got me there - the question was "Gbox sprocket for Aus conditions" and you included primary gearing mods to your bike in your answer. Good one!
Ta.
Click to expand...
 
Connie
I have been wondering about the same problem, on the N.S.W Norton Owners site there is an Exel program for changing the ratios from 19 to 24 toothed sprockets and revs. The results in both mph and kph, there is an error in the program in that you have to put the revs in the fourth gear box itself all others run with the program.
Peter
PS I was trying to find the right gear and revs for 2nd or 3rd, in the 50kph suburbs, and the school zones!!
 
Whats wrong with the stock 19T, I recond its the best one to use, mine sits on 65 MPH at 4,000 rpms and when on the highways I criuse between 70 and up to 90 MPH and it will sit on that speed all day if I let it, but you know what happens when you do them speeds here in Aussie land the fun police will get you and there are more of them around these days than in the good old days.
I just love the way the bike revs with the stock gearing and it gets to the ton pretty quickly and around town I can sit on 40 MPH in 4th gear without any problems, my motor isn't stock and has a lot of work done to it, it sits in a Featherbed frame with solid mounts and I don't have any problems with vibrations, to me the stock gearing is just fine with me and works great with my set up, but if I did go up a sprocket size i would only go to a 20T, but thats just my opinion.

Ashley
 
Ashley
My standard sprocket is a 22 tooth,I agree with your point of the anti fun mob, but here they sit with their cameras (unmarked vehicles), on the suburban streets, in the 50kph and 40kph school zones, anytime over the 24 hours! Collecting politician's pay, finding a comfortable rev and gear range, is what I'm looking at.
Peter.
 
I am mainly riding around kangaroo valley, southern highlands and the clyde occasionly. So i reckon maybe a 21t as the valley is pretty tight and wouldnt mind having the torque still quite punchy.It has the odd 100click area or at least i make it so. Havnt come across the anti fun mob yet.
Ashman, i just think the engine shouldnt be doing 4000rpm+ at 100k's. Down to the 3500 or 3000rpm i think would suit better and be less stress on the already old engine.
Chili, do you have to be a member to access the excel spreadsheet. Wouldnt mind referencing that before i make the switch.

Thanks nortiboy for your input also.

Cheers
 
Try this. Best gearing program I have found for all bikes. http://www.gearingcommander.com/
By the way, I'm about to increase my gearing from a 21t to a 22t. I use my bike to tour on and I'm sure it will pull the higher gearing fine. After all 22t was the standard gearing in the European models and they only reduced it in the US models to try to compete with the faster jap bikes at the time.

johno
 
Connive,
No any body can get the program, I think it's the same one that is on the UK NOC site. I just downloaded it to an excel program then on to excel on my iPhone & iPad it automatically upgraded.
Peter
 
hi.
Agree with Johno. I've just been thru the dilema with the 530. O ring chain , so my options are only a 19 tooth or a 22 tooth to get the chain to fit with the adjusters. I live in a rural area so my main riding will be in top gear.
cheers Hillbone
 
Now I've got some idea of this ridder Aus speed conditons plus the zero tolerance police politics, ie: mostly 60's mph cruise with some spurts up to 90's or the Ton when feeling lucky, Which is how I ride Trixie Combat and 19T is my preference but mostly for the easier 1st gear creeping around and easy ease offs w/o leap forwards in stop/go creepy conditions. I only liked the 20T before they got more police and deer here so normal for me on pre-peel Combat was 70's 80's easy base line then around the ton in the more opportune open sections. Everything we know about Norton engines says they are happiest healthiest longest lasting most efficient least stressed or heated between 3500-5500 all day long tank after tank of 6 gal Interstate. 19T will also isolate a bit sooner sweeter than higher ratio and that goes a long ways of savoring a Commando thats not being WOT'd on every whim.
 
Thanks peeps,

Chili, i checked the nsw noc website. Will be good for a comparison when i get it done.

Cheers all. Will be going with the 21t, any other mods i should be doing while the primary is off?
 
I have an excel spreadsheet I made for gearing. I find that NOC one a little difficult to navigate.

If you tell me your current sprockets ( crank,clutch hub, gearbox and rear wheel ) I can pop in a few parameters and let you know how they'll work.
 
Hello all,
At Easter I dropped a chain not the joining link another one( no damage), have obtained new rear sprocket & a 24 toothed sprocket, this was so at 50kph it would be 3000rpm in 2nd( comfortable), and also have good legs on the freeways. Now with this timely discussion, I'm reconsidering my decision, also Trojan have sprockets from 19 to 24 toothed.
Peter
 
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