Gearing Ratio's for SDGT's

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Aussie Dave
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Gearing Ratio's for SDGT's

Post by Aussie Dave » Fri Jul 05, 2019 6:43 am

G'day all,

I have been experimenting with my 17SDGT final gearing ratio's and here is some info if anyone has been thinking of making some changes.

17/38 = OEM sprockets = awful - too tall geared for Aussie roads and speed limits.... struggles in 5th at 100kph and 6th cannot be used without being caught for speeding and locked away in jail.

17/40 = 15min rear sprox change, good results, probably all that's needed..... GT still struggles in 5th at 100kph in hilly terrain with touring luggage (I used 4th and let it sing). Not quite right for our Oxley Hwy corners but pretty damn close. Adds 250rpms to oem gearing.

16/38 = 1 tooth smaller front sprox takes the abruptness away and adds 500rpms to oem gearing. Ok but seemed like it had less torque. I was surprised I didn't like it as much as I thought I would. Might try it again.

16/40 = Initially I thought it was too much, but then I felt quite happy with it..... 4000rpms in 6th = 100kph, and 60kph is fine in either 3rd or 4th. adds 750rpms to oem gearing. Excellent in traffic & around town. Feels like it has more torque than the 16/38 combo....... so it tames the beast for busy traffic duties, but retains the acceleration when asked...... for our Aussie conditions ;) ...... no unlimited Autobarns/Motorways, speed cameras and unmarked cars/bikes anywhere/anytime, tight potholed corners, narrow mountain roads etc etc.(might even be the solution for those still stalling at traffic lights etc?).

For the real world of road riding (not track days) it may well be the best setup...... the internal gearbox ratios are the problem but they are not easily changed. So 16/40 sprox's gives me all 6 gears to play with and no chuggy/luggy sensations at awkward times in busy traffic while trying to indicate and dice with d-heads.

Weather gone sour this weekend, need more riding in faster corners than Beechmont/Tamborine to be sure.

If I don't stay with 16/40, I'll happily return to 17/40...... all the above combo's do not require longer chains, but I do wonder if a 17/42 at new (longer) chain & sprox time might be the better option....... :idea:

:mrgreen:
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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Re: Gearing Ratio's for SDGT's

Post by jjscsix » Mon Jul 08, 2019 2:00 am

Good information Dave. I'm still stock, but I do think I might try a bigger rear sprocket. Just hasn't risen to the top of my to-do list yet.
2017 KTM Superduke GT, 2017 Yamaha FJR1300, 2012 Ducati 1199 Panigale

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Re: Gearing Ratio's for SDGT's

Post by mick shere » Mon Jul 08, 2019 6:04 pm

As always great write up Dave thank you mate
We have just got back from a 2000 mile round trio to the south of France, 6th gear just about hangs in 2 up with full panniers at the speed limit of 130km (80 mph) on the motorways :)

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Re: Gearing Ratio's for SDGT's

Post by pk1 » Mon Jul 08, 2019 9:02 pm

Good info Dave, I run 16/38 and it’s perfect for me on my own but when 2 up and loaded I find it wants to lift the front on any sort of acceleration. Which when trying to quickly get bye traffic on a back rd gets me a few digs in the back from the wife as it’s hard to keep the front wheel down even short shifting.
I think 16/ 40 would be mad and fun but way too much when fully loaded.
It’s possibly due to my other mods also and a combination of both.

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Re: Gearing Ratio's for SDGT's

Post by Clogan » Mon Jul 08, 2019 10:52 pm

Guess I'm in the minority, but I love the OEM gearing. I find that I spend most of my riding in either 3rd or 4th, (covers 40 - 70mph) so not much time is spent shifting gears. On the rare day I get to the interstate, I'll go to 5th, but it's rarely needed. Sixth gear? Never need it.

I just don't see the logic in spending time and money changing gear ratios just so I can shift gears more often.

(Flame suit on)

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Re: Gearing Ratio's for SDGT's

Post by GarrCano » Sun Jul 21, 2019 6:02 pm

On the SD1290GT the speed is taken from the ABS-sensor on the front wheel.

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Re: Gearing Ratio's for SDGT's

Post by Aussie Dave » Mon Jul 22, 2019 6:49 am

Speedy14 wrote:
Sun Jul 21, 2019 2:57 pm
How do you guys that change the gear ratios correct the speedometer readings? It will certainly throw off the speedometer from the stock ratios.

(My previous Ducati 1299 Panigale had a auto correction feature in the electronics for correcting changes in tire sizes or gearing) .. From my experience, when you start changing the ratios it also throws off the Traction control...

Just wondering..?
Speedy

Hi Speedy14, No changes to speedo with sprocket changes on the KTM. I checked with my Garmin sat nav..... as mentioned above, the readings are taken from the ABS sensor, not the gearbox, so only tyre size & profile will alter the speedo reading.

For info, my SDGT runs with 1-2% speedo error regardless of which sprockets I have installed and the SDGT doesn't require any reset for TC.....(no mention in the manual, nor from my KTM dealership who installed the 16t) . I have changed to Michelin PR5 tyres now (same 120/70 & 190/55) and the speedo error is the same as the oem Angel GT's the bike had from new.

:D
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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Re: Gearing Ratio's for SDGT's

Post by Aussie Dave » Sat Jul 27, 2019 7:20 am

Cheers Troppo...... I think I saw your post on the other forum..... with a pic at the Beechmont hang glider launch site cafe....... ;) .

The 17/40 is good, and will make Aussie speed limits nicer. It is only an extra 250rpms in 5th at 100kph, but it takes away most of the judder the motor gets when the revs are just that little bit to low. The other options require more surgery than simply squeezing a +2 teeth sprocket in at the back...... and probably don't yield as much bang for buck as the 40T sprocket. Be sure to read the thread on here about correct install.

I'll keep an eye out for your Black GT..... that's my coffee run - Canungra Outpost or beechmont or Binnaburra.

;)
Current delights...1290GT-2017, CBR1100XX-2005

Prev loves...Capo1200TP-014, CBR11xx-002, 2xFZR1000genisis-94, FJ1200-89, FJ1100-84, XS1100P, VF1000F-83, CX500, VF750S, KZ1000J1-81, KZ1000ST-79, CB750F2-77, CB360T-74, CB175.. started it all in 1974 ;)

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