My 1997 916sps needs a new chain and sproket set. Think standard is 15/36, wondering if 15/38 would be more suitable for road only use ? The more I read, the more confused I get !
I find 15/39 ideal on my 916, easier at lower speeds, a little more acceleration and you don't lose anything at the top end because the standard setup is geared for a top speed higher than the bike is capable of anyway.
To add, check out gearing commander; https://www.gearingcommander.com/ load the preset for your bike and you'll see the standard gearing is good for something like 180mph. Put in the alternative gearings and you can see what it will be geared for. With 15/39 you'll still see 160+ in 6th which is all it's capable of and, probably not likely in road use.
The 916SP came with a standard wide ratio gear cluster, the 916SPS came with a close ratio cluster. Also IIRC? The 996cc 916SPS's had a different primary gear ratio. So the overall top gear ratios are different between the SP and the SPS's. Steve R
Just been out and properly counted what's on there and I'm running 15/39 now. Think I'll stick with that. Thanks all . Where's good to buy set from ? Most suppliers seem to only have standard 14/36.
I use quick-change sprocket carriers on all my 3 bikes, which are in the 748/998 range. All of them have lowered gearing and I have managed to keep the standard length chain on all 3.
I also use quick-change rear (Renthal), makes future changes much easier and cheaper. As for chain length, just buy one that's longer than required and cut it to suit - I always do this as, I would worry I might end up with too short a chain if I let someone else decide how many links...
Also, if you are from Yorkshire, you can save all the small pieces and after 40-50 years join them together to make a 'new' chain...
They're nearly identical. 15 39 = 1:2.6 14 36 = 1:2.571 If you're happy with what you have you won't notice a shred of difference with standard.
That being said, increasing the rear sprocket makes more mechanical sense than reducing the front, in terms of mechanical constraints. A 14 tooth front sprocket requires more attention regarding chain tension or you will be sorry when the swing arm gets machined by a slack chain…
I recall reading an explanation somewhere of the science that, a 14t front puts more load through the chain, potentially causing more wear/likelihood of breakage. That said, when I first got my 916 I fitted a 14t front to lower the gearing as it was easier/cheaper than changing to 15/39 which would have required a new rear sprocket and chain and it was fine until I needed a new chain, at which point I went with 15/39. If you're fitting all new then 15/39 is a better option than 14/36.
Yes, more teeth = less wear per tooth. Also, odd numbers of teeth means less repetitions of teeth on the same chain links so wear is more evenly spread and the repetitions are more frequent if you have an even number of teeth on both sprockets. Checkout the section on 'same tooth - same link' on Gearing Commander.
