If I were to make a gearing change, I would go in the opposite direction - more teeth on the rear sprocket. I hardly ever use 5th and 6th gears as it is now. However, my SDR's gearing is still stock, no changes.

 

I think it would be too tall, putting around in 1st on my '16 R is a little fast at idle for my taste. But, please, if you try it out let us know what you think.

 

I doubt I would try a bigger rear sprocket (I guess I should write that as "gearing change", either front or rear). My SDR already feels super short in 1 through 3. I have absentmindedly started off at a red light in third several times now, and it barely made any complaint. :surprise: And I'm not the guy who worries about not using 6th gear at lower speeds, if I'm going too slow and the engine isn't happy then 5th it is. 6th works fine at velocities you'll lose your license at!

And if you go down a tooth in the front won't that just leave you with something like a 4 speed with two overdrives? And maybe it would lose that hooligan feel, which I would certainly miss.

Anyhow, if the OP does make any gearing changes I'm definitely interested in hearing about the results :grin2:

 

G'day you SDR hooigan's .... :wink2:

The general rule of thumb for gearing is 1 tooth on the front is equal to about 3 teeth on the rear.

The SDR & GT have a 'quick change' rear sprocket system, thanks to the single sided swing arm - it takes 15mins to swap a rear sprocket once you have done one.

So if you really want to make your gearing taller/longer, going +1 front to an 18 = going -3 rear. I think it would be better to go -1 or -2 on the back if available (I forget what the SDR has on the rear....? is it a 38t?).

Basically an 18 tooth front on an SDR would make 1st gear much taller (more clutch slip on take off) and could make 5th and 6th only useable at very high speeds....... I've not ridden an SDR but I assume it is geared for hoolganism vs my Gt geared for Autobahn touring.......(I had to shorten the gearing from 17-38 to 17-40 to make the motor work smoother at 100-110kph Aussie speed limits).

Anyway - it is much easier to do the rear change and you can experiment 1 tooth at a time rather than a 3-3.5 tooth jump (caused by +1 on the front). Just be sure you observe which way the oem sprocket comes off.....

Cheers..... Ps sorry, last minute pics.... forgot, my part no is for a 40t which is not what you need.... but the others are relevant to 1290R's.

Pps One other trick is to buy a tyre that is physically larger/taller (but still branded to the correct size) - this is true..... i can hear you laughing.... but usually Bridgestones are 'bigger' than Michelins and Dunlops are the smallest for the same size........ the problem is finding a tyre fitter who actually knows which tyre gives a slightly bigger rolling diameter when fitted to the bike....... might be easier to just use that gearbox and ride it.....:grin2:

 

Does a 1 tooth in front OR 2 in back change warrant needing any fueling/mapping adjustments.

I have completely stock SDGT. Don’t plan to make any modifications.
However, I had thought about possibly doing this.
But I don’t want to do it if will require fuel mapping work.

 

:grin2:@;

G'day PC1978,

Short answer is no. It's just correcting a slight final drive gearing issue if it is bothering the owner (we all have different speed limits/road designs etc). I was happy to just ride my 17Gt as a 5 speeder as it wasn't too bad, but once I was able to buy a 40t rear sprox, I found it was a vast improvement in smoothness as it allowed the engine to stay close to it's sweet spot ..... eg now 3rd is totally happy in our 60kph traffic zones and 5th is still happy at 100kph, but 6th can be used from 110kph (instead of 130).......

No need for any tuning - it's simply a final gearing adjustment to suit local conditions and a worthwhile mod for anyone with a traffic component to their riding. I still get 22km/Ltr fuel readings when I'm cruising on the motorway0.... so it's a mechanical adjustment rather than a performance mod.

As an example, my GT is like yours, still stock, I haven't removed the SAS or charcoal filter etc etc - though I would like the extra space under the seat for puncture repair kit/tools - and it makes more than enough HP in stock trim. I've just put a K&N airfilter in (which is in the KTM powerparts catalogue so it's an official accessory) and the GT will tune itself to the filter anyway.

You may feel that you only need the 39T rear (+1) - what I know is the 40T raises revs in 5th gear at 100kph by 250rpm......(i was looking for 200rpm anyway), so the 39T would raise revs by approx 150 (I couldn't buy one to test this but others in the UK with higher motorway speed limits have done the +1rear).


Ps Be warned.... -1 front is way too much for the SDGT (=+3 rear)...... the SDGT is only slightly tall geared and only needs +1 or +2 rear max, to trim the tallness away so the motor is less chuggy in traffic (eg like a Jap gearbox..... just works without thinking about having to change to 2nd at 55kph and rev at 4500rpm).

Pps bikes are all different..... i had Caponord1200TP before the SDGT, and it was ridiculously tall geared - had to clutch it in 1st in low speed roadworks zones..... and it was a heavy clutch! It really needed -1 front and that made it a normal bike, able to ride easily in traffic, yet not rev it's head's off at highway speeds

 

Cheers PC1978........ you can always buy two sprockets (I liked the steel 'Supersprox' vs the alloy racing style, for normal road usage), a 39t and a 40t....... that way you can fine tune to suit......but the 40t will be the one to have if you don't want another sprocket gathering dust on the shelf....... the 1290 donk likes to spin freely rather than chugg awkwardly..:wink2:

Just be careful when installing - back off the eccentric chain tensioner (easy) & undo sprox nuts - remove sprocket with chain on (install same way, ie with new sprocket already in the chain loop)..... it may be a tight squeeze if you haven't done enough miles to put a bit of slack into the chain (that's where a 39t will be easier to fit)...... I did my 40t at about 10k kms because I had to wait that long to find a steel sprocket, then Supersprox was out of stock......, then luckily my local KTM dealer was able to order from an Aussie source, so I didn't have to pay for freight USA-Aus.......:laugh2:...... what a saga...... but bits for the GT were scarce in 2017...... different story now though!

Oh, nearly forgot, put the sprox on correctly to line up with the front sprocket...... machined side goes in see pic... (oops..... posted twice....... must be getting oldtimers disease.....:laugh2.