Gearing Advice Needed

[wozza]

Hi
Gearing for some reason does my head in
Original gearing was 14 front 38 rear, 110/90/18 wheel size
due to not being able to get a 38 rear at a reasonable price and locally(bike is an old grey import) I opted for 36 tooth rear
so now I have 14 front 36 rear and 120/90/18 wheels size.
The issue is the 520 chain was now a tad to long so Ive shortened it the min I can, now its just long enough lol
If I go 13 tooth on the front that should bring me back close to the original ratio and a bit more length to the chain to boot.
Anyone know of any issues like extra strain somewhere in the drive train ?
Thanks

 

[ridesolo]

One tooth difference on the front sprocket is a greater difference to the final ratio than two teeth on the rear. I recommend that you try messing around w/ one of the following tools:

https://www.gearingcommander.com/
or
https://www.blocklayer.com/chain-sprocket.aspx

 

[wozza]

Thanks for the quick reply
Already check out some of the calcs..Im aware of the cause and effect of the change, but have no knowledge of the consequences of running smaller sprockets
cheers

 

[Rider52]

I doubt you will notice the difference. The easiest way to calculate your ratio is to divide the driven sprocket size by the driving sprocket size. In this case 38/14 will be somewhere around a 2.71 ratio. The new sprockets 36/13 will take you to around 2.57. In theory this should give you a bit slower acceleration through the gears but a higher top speed.

 

[Pete12]

Try this calculator, it has a heap of different bikes already loaded in and you can set the wheel diameter to suit. Use the custom feature to load in whatever you need and it will give all the speed details from different gearing.

Gearing Commander - Motorcycle Speed and Drive Train Calculator v7

Motorcycle speed and sprocket calculator with bike database for gearing, sprockets, tires and chains of over 1750 bikes. Request yours to be added as well.

www.gearingcommander.com

The difference in wrap between a 13T and 14T will be negligible so no problems there.

 

[wozza]

I prefer https://www.blocklayer.com/rpm-gear-bikes.aspx ...I use this site's calcs/converters all the time
Im aware of the general changes see attached pdf file...but am curious as to the added strain on the transmission due to added force needed to move a smaller tighter curved sprocket ect..Ive already notice chain is now very close to the pivot point of the swing arm.... but there is a rubber guide on that area and it just kisses it.....