Haaiii Evzeebodiys (Haaii Doktor Nick.) I was wondering if anyone knows how bad an idea a 13 tooth front sprocket is. From what I could gather from reading previous posts, 15 seems to be the standard minimum for the front, and well, I know it's advisable to go large at the back instead, but how bad an idea is it to go 13 until I can get a 15 toother or maybe 15+larger back sprocket (15 alone may not cut it after using the 13)? Thanking you in advance. Cursing you in advance (yes YOU know who YOU are)
depends on what kind of riding you do. if its lots of highway 13 might not be the desired size, i do lots of city riding and i wish i had gone down to 13 as a few people have told me it makes the bike a fair bit more zippy
Not much highway/freeway, FurryFrog. It was more from a perspective of damage control (the chain and...?). I guess the engine would be under less stress in general though as it doesn't have to generate as much torque all the time? (unless you make it) Koma really seemed to sell the back sprocket approach over the front, and that's just talking 17->15 swap. But it would have zip in abundance. 17->13 = almost a third more torque. I just wanted to make sure I'm not about to do something I'll regret. If you know people that have gone 13 and their bikes are still ok that makes me feel better, so thanks.
I wouldn't go 13 on the front, as a general rule 1 down on the front is equivalent to 2.6 up on the rear. Also the sprocket will wear quicker and its usually the sprockets that go before the chain goes if you take care of the chain that is. If you want more acceleration maybe just go one down on the front and see how that feels. Top speed will decrease to about 150 - 160. Or go the whole hog and get a 525 or 520 conversion (i don't recommend this option though).
I'd honestly say that a 13 tooth front is going too far, but atleast try it out and see how it goes! If you like the amount of zip you get out of the 13 then just order a rear sprocket with ~5-6 more teeth on it and go back to a 15 front. Chain life on a 13t front will suffer a HUGE amount! If you decided to clean it regulargly and ensure it was always lubed properly (ala Scott Oiler perfection) i'd still say you wouldn't get more than ~10k out of it before dead links started to appear. For reference sake i got ~20k out of my FZR250 chain with a 15t front, and i'd estimate regular chain life with a 17 to be ~30k kms. Of course all of these numbers are to the point when a chain starts to get dead links; you can continue to use this chain but it'll be robbing power and feeling a bit sluggish. As i'm sure you realise the deal with chain wear is directly related to the turning radius and therefore the amount each chain link needs to bend going around a sprocket and then straighten. Smaller the radius, the greater the wear rate; that's the reason i'm so for rear sprocket changing.
