I have a 2005 620 Dark... When it was last in the shop my tech told me I would need a new chain soon. I believe these came stock w/ a 15/48 ratio? Since I am getting a new chain I figured since I should go ahead and swap out both sprockets. Does anyone have any feedback on gear ratios that have worked well with a 620. I don't really know much on this subject but I have been thinking about a 14t up front and a 46t in the rear? What can I expect with these changes? Can someone please give me some insight on pros/cons of brands and anything else I might need to know. Also, what kind of chain should I be looking at? If I go w/ the 14/46 will a 108 link chain be sufficient? It's only a 620, not an S4Rs so I don't need top of the line, but still want quality parts.
Thanks,
JSnide
going down to 14t in front will give you more low end pep.....something the 620 is in need of.
leave the rear alone.
First up - I'm not sure about what the OEM gearing on a 620 is, but 15/48 sounds a little short, I vaguely remember 15/46 on them.
Secondly, there's bugger all difference between 15/48 and 14/46 - almost certainly a small enough difference that you won't notice it unless you measure carefully with accurate tools (it's under 1% different, I know I wouldn't "feel" that.)
Thirdly, shorter gearing is almost universally considered "better" by most Monster owners (with some differences of opinion mainly from S4 owners in my recollection). The almost standard "best value for money improvement ever" advice is "fit a 14 tooth front sprocket". It gives you more zip off the line, and better low speed control. I'd say at least 9 out of every 10 people who try it say its a good thing. (there are a few people who don't like it, based on one of two problems - some bikes end up with undue chainguard wear, more prevelant on bikes with raised rear ride height but also reported on at least one bike in stock configuration - and some people just don't like the slightly higher "cruising speed" revs)
My advice? Stick with whatever size rear you've currently got (48 or 46, make sure you know where you're starting from), and drop the front to a 14. If you _don't_ like it, you're only out the price of the 14t front sprocket, and you can throw a new 15 on and use the same chain. (if you change gearing by a few teeth on the rear, you're more likely to end up needing to change the chain length if you want to revert the change).
(Oh, and don't worry about losing top end speed - smaller motored Monsters can't pull peak power revs in top gear anyway. A guy on TOB, Jim Gnetki, had some pretty accurate modelling software which said my 750 would go ~3mph _faster_ in top gear with a 14t front compared to stock 15t gearing)
big
Thanks for the replies guys... I should have mentioned that my bike already had a 14t put on when I got it. In my manual it says that the 620 Dark Monodisco came with 15/46 and the 620/620 Dark Dual Disc came with 15/48, anyone know for sure? I guess I can count them next time I pull my bike out. I just recollect reading somewhere that there were better gearing options with a 15t upfront? Also, isn't it smart to change sprockets along with chains? The 14t upfront is only about a year old, so I should be good there, no?
Also, what kind of chains do you guys recommend? Ca-Cycleworks sells DID and Monsterparts sells EK? Just trying to get some good advice and input before I buy these things.
Thanks again,
JSnide
620 5spd = 46
620 6spd = 48
I have the 6spd. Stock 15/48. Went 14/48 for a while. Liked it but was too short for highway cruising. Went to 15/51 and like it. A little taller than 14/48, but wont let me fit my case-saver with the 15 up front. Think I may go 14/47 next. It'll allow the case-saver but wont be quite as short as 14/48 was.
my $0.02
Yeah I've got the 6spd as well [thumbsup] If you do swap to the 14/47 let me know how you like it. I was just reading about a 696 owner who was about to change to that same setup.
Quote from: rule62 on May 07, 2009, 06:44:26 AM
620 5spd = 46
620 6spd = 48
I have the 6spd. Stock 15/48. Went 14/48 for a while. Liked it but was too short for highway cruising. Went to 15/51 and like it. A little taller than 14/48, but wont let me fit my case-saver with the 15 up front. Think I may go 14/47 next. It'll allow the case-saver but wont be quite as short as 14/48 was.
my $0.02
I was just thinking the same thing with highway cruising. My 620 is 5spd with stock gear ratio. When cruising on highway at 70, the bike seems to be reving pretty high. Wish I have the 6th gear. So if I was going to change the ratio, I would probably make it a bit taller for commuting. Might change it to 15/51, like you did to see how it is.
If you've got the 5spd then you've got a 46-T rear stock. If you want it TALLER for commuting, you'd want to reduce the # of teeth on the rear sprocket. Increasing the # of teeth on the rear makes gearing SHORTER and would make highway cruising/commuting even buzzier.
I ran 14/48 for 6K miles and liked it, but agree that it was a little tall for the freeway...80mph = 6K rpm. I just switched to 14/46 and like it better. Like bigiain said, it's barely a difference from 14/48, but there is a difference and I don't feel like the bike's screaming quite as much when I'm just commuting on the slab.
Quote from: rule62 on May 08, 2009, 09:58:09 AM
If you've got the 5spd then you've got a 46-T rear stock. If you want it TALLER for commuting, you'd want to reduce the # of teeth on the rear sprocket. Increasing the # of teeth on the rear makes gearing SHORTER and would make highway cruising/commuting even buzzier.
You are right... I got my math backwards. That's what you get for posting in the middle of the night.
whats wrong with 80 mph = 6k?
puts you right in the middle of the best part of the power band.
Quote from: herm on May 09, 2009, 05:27:25 AM
whats wrong with 80 mph = 6k?
puts you right in the middle of the best part of the power band.
I didn't say there was anything wrong with it, just higher than I prefer for freeway cruising. In the twisties is a different story. [moto]