Rear sprocket size?

[olden mgroin]

hey all, don't know if this has been posted before, but would like to know how many teeth on standard rear sprocket, and does a larger sprocket give better acceleration. (just lookin for a cheap mod).


any help appreciated.http://forums.sv650.org/images/icons/icon14.gif

[Stu]

44T for your faired bike
45T for a Naked

Yes larger rear sprocket will increase acceleration & reduce top speed

Alternatively std front sprocket is 15T & the opposite smaller front sprocket will increase acceleration & reduce top speed - it will have 3 times the effect, or equivalent to going up 3t on the rear.

You can always do both, just watch out chain lenth, eg 14T front would have no effect :smt102 but 47T rear would need more links
HTH

[olden mgroin]

how much reduction in top speed are we talking, will it still pull 100+?

[Stu]

Blue worked it out as 127 revs per tooth & I reckon one more tooth on the front reduces my revs by 500 in top.

So say your top speed now is 135 at 11,000 revs 3 Teeth up on the back would be 125 at 11000 revs (but maybe the engine will have enough power to rev higher as you are going at a slower speed?)

[olden mgroin]

thanks stu very helpful, larger rear sprocket for me then.

[Mr_Chin]

I read about changing the front sprocket in this months RIDE magazine, and they say it will make a considerable difference. Has anyone on the org actually done this, and is there a big difference in the pull off? would I need to do the reverse of more teeth on the rear - by shortening the chain with this mod?

I assume this mod is like putting lighter rollers in the variator of a scooter, thus giving higher revs and giving more bite? It's nice to read about things like this, but I'd prefer 'hearing it from the horses mouth' so-to-speak.

Chin

[BillyC]

Alternatively std front sprocket is 15T & the opposite smaller front sprocket will increase acceleration & reduce top speed - it will have 3 times the effect, or equivalent to going up 3t on the rear.

Just a bit of due warning about doing this - reducing one tooth on the front sprocket greatly increases the wear on the chain, and front sprocket - and therefore the rear chainring as well.

[leegriffiths128]

I changed the rear sprocket to 46T......can't say I noticed a discernable difference in acceleration. However, I preferred the way the bike rides with the standard sprocket if that makes any sense. When the 46T wears out, I'll be dropping back to standard I think.

Probably everyone else on the org will disagree with me though.....horses for courses and all that :)

[Sideshow#36]

1T up on the rear is hardly noticable! I'd go to a 14T on the front for any noticable difference, and the wear isnt that much faster than the standard 15T. I depends how well you look after your chain too.

[leegriffiths128]

46T on a pointy is two teeth up aint it :confused:

[hollayzfr1]

Hey guys,


Just changed my front sprocket to a 14 tooth one.

Must admit not all that blown away with the difference, hardly noticeable to be honest.

Now I'm thinking about going up on the rear. Anyone know how many teeth I could go up before a new chain is in order?

Think the chain on my bike is the Factory one, it's in perfect nick.

Cheers :smt001

[yorkie_chris]

1T up on the rear is hardly noticable! I'd go to a 14T on the front for any noticable difference, and the wear isnt that much faster than the standard 15T. I depends how well you look after your chain too.

It's quite marked IME even with a scottoiler and regular cleaning.

Reason is you increase the tension on chain for a given acceleration markedly.

Better option is a larger rear one, 48 works good.

[upandrunning]

Hi guys... I'm planning on make a change of ratio on my front and rear sprockets cause I hate how crotch rockets beat me all the way around on the straights when I'm on the track. I mean, first 100m they have to deal with my torque, but after they're up in the revs, they are gone. In a track crowded with 600cc only bikes I would like to be a little more competitive without changing the hole bike. I love my sv naked bike. I'm willing to sacrifice a little torque by some top end speed. I'm using Standart sprockets currently my question is: what is the max I can go in the front sprocket and the min for the rear one so I can consider what would be best for me.?

Cheers.

[Purity14]

On my streetfighter cbr, i dropped two at the front and gained 3 at the back, its pretty lively.. Not interested in top speeds or motorway usage on this bike, its bearable.. But around town and on the twisties its great..

I rode to romania on a 15t front 47t rear, and swapped out to a 13t front for the transfargen.. It was worth it ;)

[Red Herring]

I have 14/44 sprockets on my pointy and she hits the rev limiter at 121mph according to the SatNav.

Changing the final drive ratio (sprockets) isn't going to suddenly allow you to keep up with 600cc sports bikes around a circuit. They have 50% more power than you and that isn't something you are going to be able to get round easily. By lowering the gearing you close the ratios up which allows you to keep the engine in it's "sweet" spot more easily as the gap between gears is less, but it does mean you will be changing gears more often. If you spend most of your time playing hard on country lanes then it's worth doing, if you commute or don't ride very progressively then it's not.

[madcockney]

For those with Android phones can I suggest that you download the "Calcola Rapporti" app from the play store. This not only gives you your particular make and model of bike, but what the speed is in each gear at any RPM you specify, and what that will be if you change the sprockets. Note use this as indicative only and also does not allow for any slippage of the tyres etc. For instance the speed that RH mentions with 14/44 sprockets, (and standard wheels/tyres), you would achieve, according to this app, at 9250 rpm, which I would have thought was different to the actual revs that RH was actually doing

[Red Herring]

For instance the speed that RH mentions with 14/44 sprockets, (and standard wheels/tyres), you would achieve, according to this app, at 9250 rpm, which I would have thought was different to the actual revs that RH was actually doing

That's quite a big difference given the rev limiter is at 11k and I'm definitely hitting it (got it on video here)

https://www.youtube.com/watch?v=QmLpdGnpCqU

at 2.05 in

The Sat Nav said 121mph afterwards. I've been playing with that app you mentioned but that's suggesting a speed of over 140mph on that gearing and that clearly isn't right. Are you supposed to change the numbers in the boxes next to each gear, and if so how do you know what to put in there?

[upandrunning]

Changing the final drive ratio (sprockets) isn't going to suddenly allow you to keep up with 600cc sports bikes around a circuit. They have 50% more power than you and that isn't something you are going to be able to get round easily.

Good point mate.

Thanks to all for your your comments.

Cheers.

[yorkie_chris]

Gearing commander reckons 133.4mph at 10200rpm with 14/44.

[Red Herring]

Well I am genuinely confused then. I've just been out and pulled the sprocket cover off to double check and it's definitely running 14 front, 44 rear. I've even watched the video again and counted the gears to make sure I was in 6th (you never know!) and it's certainly hitting the limiter. We had been half expecting it to in practice because we considered changing the gearing, but there was only a couple of places on the 30 miles of stages where it was an issue so decided against it. Maybe the Sat Nav lies, but it didn't feel like 130+ so I'd be surprised if it was wrong. That only leaves rear tyre size, and it was a 160/60 Dunlop.

And why is this now in "Stuff Wanted"?

[yorkie_chris]

fook knows, probably same reason we're discussing a 5 year old thread!

[Red Herring]

Shows how observant I am....I hadn't even noticed! Perhaps the discrepancy in the figures is down to inflation?

[punyXpress]

Hi guys... I'm planning on make a change of ratio on my front and rear sprockets cause I hate how crotch rockets beat me all the way around on the straights when I'm on the track. I mean, first 100m they have to deal with my torque, but after they're up in the revs, they are gone. In a track crowded with 600cc only bikes I would like to be a little more competitive without changing the hole bike. I love my sv naked bike. I'm willing to sacrifice a little torque by some top end speed. I'm using Standart sprockets currently my question is: what is the max I can go in the front sprocket and the min for the rear one so I can consider what would be best for me.?

Cheers.
If you do that you'll knock what acceleration you have quicker than a punter in a knocking shop!

[upandrunning]

Thanks mate.

I will consider it.

Cheers