As title says, is there enough scope with the chain adjusters to accommodate swopping rear 37t to a 40t sprox? Has anyone tried?
gpember2 Been wondering this myself. Looked on a few forums and sites selling chain / sprockets and it looks like to go to 15/40 even 15/39 you need 98 links. Obviously check this before buying. Cheers Gaz
Hi, I went to 15/39 with the standard chain and it just about worked by pulling the wheel nearly as far forward as it would go. If you go on the gearingcommander.com website it gives you the differences in speeds/revs for different sprocket combinations and number of links required. Haven't counted the number of links on my chain but it was standard for a '96 900ss when I originally changed the chain and 15/37 sprockets.
I'd be surprised if a 3t change won't require a longer chain, but even if it fits I would say you should get the longer chain anyway to keep the wheel base nearer to it's current setting.
As Sparch says you could squeeze it but most of the sites I looked at quoting 15/39 & 15/40 and selling in a kit with chain quoted 98T and would agree with Desmoduke. Also look up polygonal effect when dropping to 14T it might be negligible but in my opinion you are going in the wrong direction regarding wear and smooth running of chain. As Our Graham used to say on catch phase - "the decision is yours". Cheers Gaz
There is a substantial increase in torque and a minor loss in top speed when dropping to a 14 front; whereas there is minimal torque gain and minimal speed gain by upping the rear. Frankly, I would leave the stock settings alone because changing sprocket sizes only moves any 'issues' to another rev range or gear.
Fitted 15/40 with std original 96 link chain last night without any issue to my surprise..... Chain adj set just before half way! Sure the chain has a bit of stretch in it after 10,000miles but still I'm surprised.
Theoretical stuff drive dia driven dia crs dist 96 link crs dist 98 link 15T 76.35 37T 187.19 552.831 568.70 15T 76.35 38T 192.24 548.64 564.515 15T 76.35 39T 197.28 544.32 560.27 15T 76.35 40T 202.33 540.004 556.006 15T 76.35 41T 207.38 535.73 551.71 *** sorry can't get columns to line up *** You can see that 15/37 on 96 links and 15/40 on 98 links have similar centres within 3mm. Because I have not got my arse into gear I still have engine and swing arm in bits which made it easier to measure. I got output shaft to pivot = 70mm and pivot to extremes of adjustment of 466 & 506. Assume these two lengths are in line at some point in their lives due to suspension going up and down, they don't look too far off we get theoretical sprocket crs of 536 min / 576 max. gpember2 - 15/40 on 96 links = 540.004 Halfway crs would be 556 so a bit before would say 550, that's 10mm crs increase which is approx 20mm increase in chain length (I know it's not parallel), which is 0.208 per pitch – does that sound realistic? Anyway, I am off to get a life, Cheers Gaz
