Date: 28-03-24  Time: 17:25 pm

Author Topic: chain and sprockets - dropping/raising teeth?  (Read 5552 times)

mickvp

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chain and sprockets - dropping/raising teeth?
« on: 13 February 2015, 08:42:50 pm »
Good evening Foccers!

just wanted to pick the brains of you gents. My Thou is still on its original chain and sprockets, and although its only done 10k miles, its also now 10 years old, and so has some surface rust and has generally seen better days. So I want to get it changed in the next few weeks before dragging the bike out and readying it for the coming season (I've also got new tyres to go on so the wheel will be off anyway).

I was thinking of either dropping a tooth on the front, or maybe going up 1/2 teeth on the back. Although I do the odd days commuting in nice weather, most of my riding involves weekend and evening blasts up the loch side (A and B roads), and so economy is not really a factor (nor is going over about 100mph at any point). Is this a wise move - altering the amount of teeth? has anyone does either of these tweaks and what sort of change is it in real world terms? I did have a look on gearcommander, and so know what sort of "on-paper" change it shows.

I would only be doing either or I think - I dont think I would want to go as extreme as dropping a tooth at the front AND going up 1 or 2 at the rear.

Finally, can anyone recomment a good chain? I fancy a gold one like I put on my old 600 fazer, as I think they look nicer  :o :rolleyes .

Thanks as always :)





slimwilly

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Re: chain and sprockets - dropping/raising teeth?
« Reply #1 on: 13 February 2015, 09:00:12 pm »
How many teeth are on the front (standard?)
i have taken one off the front ,a gen two, i may be mistaken but i thin it now is the same as the old gen1 .


I love it, it was too high geared and who is going to do 160 mph? :lol
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mickvp

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Re: chain and sprockets - dropping/raising teeth?
« Reply #2 on: 13 February 2015, 09:29:10 pm »
How many teeth are on the front (standard?)
i have taken one off the front ,a gen two, i may be mistaken but i thin it now is the same as the old gen1 .


I love it, it was too high geared and who is going to do 160 mph? :lol

16 front, 44 rear mate.

Thats my thinking too. I would rather have a little bit more acceleration, rather than just being able to do a speed I will never do.

nickodemon

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Re: chain and sprockets - dropping/raising teeth?
« Reply #3 on: 13 February 2015, 09:43:44 pm »
Remember if you change the gearing you can't adjust the speedo to match (i think!)
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Ian-man

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Re: chain and sprockets - dropping/raising teeth?
« Reply #4 on: 13 February 2015, 10:05:35 pm »
I dropped 1 tooth on the front and raised 2 on the back.
It upped the revs at 70mph by about 500. I still get about 170 miles to a tank. Acceleration is better obviously.
It does send the speedo out of wack, you could make a mark on the speedo where the proper limits are but I got a speedo healer and adjusted that until my speedo matched my phone gps.
I got a gold x ring chain with renthal sprockets 'racing gearing' kit off ebay from a bike shop.

I asked them about changing both sprockets and they said 1 tooth off the front was like putting 3 on the back so putting  2 on the rear wasn't a big step.

I will see if I can find a link for the kit I got.
It was arracing-uk but they don't have a racing kit listed at the minute.
« Last Edit: 13 February 2015, 11:30:42 pm by Ian-man »

mickvp

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Re: chain and sprockets - dropping/raising teeth?
« Reply #5 on: 13 February 2015, 11:20:37 pm »
Nick as Ian has said, you can get a speedo healer to correct the readout :)

Ian, thanks for that. Although your right, there is no "kit" listed for our bikes, they do sell all the component parts individually on ar-racing. Its only about £14 for a front sprocket, and about £35 for a rear, so I could maybe buy a couple to try out different setups I suppose.

Still interested in hearing others experiences of changing the amount of teeth as well though :D
« Last Edit: 13 February 2015, 11:21:18 pm by mickvp »

Ian-man

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Re: chain and sprockets - dropping/raising teeth?
« Reply #6 on: 13 February 2015, 11:32:48 pm »
I'm sure if you spoke to them they would be able to sort you out.

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Re: chain and sprockets - dropping/raising teeth?
« Reply #7 on: 14 February 2015, 08:11:30 am »



I was reading about this the other day as I was considering reverting back to the standard sizes on my Honda. Seems like there'l be a loss of rear wheel horse power when changing sprockets from standard:


http://www.superstreetbike.com/how-to/bigger-rear-sprocket-makes-more-horsepower-mythbusters


DID chains have always served me well. Expensive but worth it, I don't buy anything else these days.
is it clean enough?

mickvp

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Re: chain and sprockets - dropping/raising teeth?
« Reply #8 on: 14 February 2015, 12:24:59 pm »
I assume if the BHP will decrease on paper, the torque will increase by the same proportion. Though?

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Re: chain and sprockets - dropping/raising teeth?
« Reply #9 on: 14 February 2015, 01:30:06 pm »
Id like to decrease top speed and i crease accelaration, it makes perfect sense and what a cheap way of doing it.


My chain and sprockets are reasonably new though so ill leave it for now and considering how much my bikes been tinkered with i imagine it already has different toothed sprockets.


Do it Mick, do it 8)
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Re: chain and sprockets - dropping/raising teeth?
« Reply #10 on: 15 February 2015, 02:41:18 am »
Changing sprockets has almost zero effect on rear wheel BHP - that's determined by the state of the engine and driveline friction losses - unless your chain is rusted with seized links and your sprocket teeth are hooked.

You can get exactly the same rpm effect (higher revs for a given road speed) by simply riding along in 5th gear, rather than 6th.

I seem pretty much alone on this usually, as I can't understand why anyone would put a smaller front sprocket on, unless they were drag-racing. The Gen 1 is already a high-revving bike, so why make it worse - and the smaller sprocket increases chain wear (although only fractionally).

If you just ride in 5th gear, you always still have 6th available for those times when you want a bit more of a relaxed ride.

Like I say, I seem to be a bit of a lone voice on this, but I really don't understand why people have a "need" to use 6th gear, if they want to use higher revs at a given road speed. The thing is, once you change the gearing this way, if you get fed up of the revviness, you can't go back to original unless you buy another sprocket and go through the hassle of changing it. If you leave it standard and get fed up, you can just change up into 6th gear.
« Last Edit: 15 February 2015, 02:45:51 am by Millietant »

Ian-man

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Re: chain and sprockets - dropping/raising teeth?
« Reply #11 on: 15 February 2015, 12:50:49 pm »
You have the wrong idea.
Yes in top gear the revs are higher for a given speed but thats not the reason for the change.
Changing the gear ratio lowers the effort required to push the bike along so increases the acceleration at lower revs and lower gears. This gives better acceleration with the negative effect of higher revs at motorway speeds and poorer mpg.
It depends what you want to do with your bike. Cruise about or blast up and down the twisties.

Millietant

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Re: chain and sprockets - dropping/raising teeth?
« Reply #12 on: 21 February 2015, 11:25:59 pm »
We'll have to agree to disagree on the technicalities Ian, everything I've done in engineering and maths over the last 40 years has backed up thee simple fact that changing the sprockets (smaller front/larger rear) simply changes the overall drive ratio, increasing RPM's in each gear for any given road speed. Because the engine is spinning higher for a given road speed, more power and torque is available at that speed - hence, the bike is much more responsive and accelerates faster, per gear.


BUT, the exact same effect can be had by simply riding along in one gear lower than you do now - the gearing computations others have provided links to from other posts prove this, beyond a shadow of a doubt.


I'm not saying don't change the sprockets, I'm just pointing out that if you always match your desired RPM's to your desired road speed, you generally don't need to change sprockets - and being a tight-arse, I'd rather keep the money for the sprockets in my pocket and just use a lower gear to keep the revs up when hooning about, to get the response I like.




Andy FZS

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Re: chain and sprockets - dropping/raising teeth?
« Reply #13 on: 22 February 2015, 12:41:15 am »
To my simple mind changing sprocket teeth will only alter 1st and 6th gear all the other gears are just ratios in between.  Ok it makes sense to me.

noggythenog

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Re: chain and sprockets - dropping/raising teeth?
« Reply #14 on: 22 February 2015, 03:42:21 am »
both arguments seem to make sense when reading them and at first thought I was thinking that changing sprockets made perfect sense but now after going through it all I tend to agree more with Millietants view - to a point.

I'm shooting from the hip here as I know foc all about it and like everyone else it's just how I imagine it in my noggin but.......

for example lots of folk moan about high revving inline 4 engines such as the  :faz  power delivery "oh you've gotta rev them to get the power out", say for example the FZ6 compared to the FZS600 and the moan is that the old bike has more mid range. Well yes this is right but if you know that you're bike contains its power higher up the rev range then that is where you should be when you need the power - I think what folk really mean here is that they want to be in top gear as soon as possible and then complain when they have to change down gears to get to the power...more so than they would on another bike - the revs seem high or the gear seems too low to them - it is more about perception of what gear they are in or how much fuel economy they are getting rather than where exactly they should be in the rev range for performance.

so yes I agree, just choose your gears better for the majority of the time.

where I disagree is on this technicality - the transition of gears -  ok I would say that nobody really needs any more thrust in 1st gear....if you are giving full throttle from the go in 1st and finding yourself still needing more acceleration then there's something wrong surely.

2nd gear is a possibility depending on what bike ie 600 or 1000...personally I wouldn't want any more oomph in 2nd on the thou.

3rd gear then - perhaps you find that being low in the revs in 3rd gear means that the bike is a little sluggish under full throttle until it gets to higher revs - so you could as we've discussed be in a lower gear, 2nd gear but then you might find yourself at that same road speed being far too high in the rev range in 2nd so that there ends up being a gear change needed right in the middle of where you need to be having that spread of power - this isn't ideal because I think everyone would rather not have the extra hassle of a gear change if it involves overtaking or if you often find yourself in this particular gear/rev range scenario it will become laborious - this is where I can see the benefit of changing the ratios to perhaps do away with that particular gear change at those road speeds.

As it happens on my Gen2 I have found that the most used gear/rev range scenario on normal British roads for me is for overtaking cars very swiftly on A roads whereby I've found that holding the revs high in 3rd gear at those road speeds allows me instant, powerful and smily faced oomph for approx a 2 car overtake before I'm changing to 4th gear and that's fine for me, if I was only getting passed 1 car or say almost getting passed 1 car before needing to look for 4th then id consider a sprocket change because passing 1 car is a common occurrence on the roads and it only takes 1 missed gear change to then be in world of shit or embarrassment -  simply being in 4th gear at the beginning would mean a slower overtake so that is no good and being in 2nd gear would mean not enough useable revs left in the bank and again require a gear change mid overtake.

so that's my tuppence worth anyway, I think it depends really whether you often find yourself changing gear when youd rather not be - the required change may actually be in the opposite direction than you'd imagine....yes generally you may feel that you need more acceleration but in actual fact you could end up getting better real world results by making the gearing longer yet being able to stay in a lower gear for when you need that acceleration most ie " my bike is slow in 4th when I need to overtake....I need more acceleration" - make the gearing longer so that you can use 3rd for longer and use 4th more as a cruiser could be more beneficial maybe???

« Last Edit: 22 February 2015, 04:58:22 am by noggythenog »
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Re: chain and sprockets - dropping/raising teeth?
« Reply #15 on: 22 February 2015, 09:37:12 am »
You have the wrong idea.
Yes in top gear the revs are higher for a given speed but thats not the reason for the change.
Changing the gear ratio lowers the effort required to push the bike along so increases the acceleration at lower revs and lower gears. This gives better acceleration with the negative effect of higher revs at motorway speeds and poorer mpg.
It depends what you want to do with your bike. Cruise about or blast up and down the twisties.

I can't imagine wanting more acceleration in the lower gears. The thing hoists the front in 3rd if you really give it some welly as it is. Isn't it more about learning to use what you have to better effect? Higher revs gives you more acceleration, it's just learning to use clutch and throttle to get the most from it. That's one of the things I love about the gen 1 - it's a Jekyll and Hyde bike. You can potter around in high gear, cruise on the motorway without caning it (more to do with cc) or ride it like a sports bike by keeping the revs up where the power really starts to matter. I can't imagine needing more on the road for an everyday bike. If you are actually wringing every ounce of acceleration out of it often, then you have more nerve than me!

It was pointed out to me that most people hardly touch full throttle on the road. So, being the idiot I am, I tried it, and I don't mean just on long straights.  :eek  Nope, my bike's got plenty thank you very much!

Perhaps I'm just getting old  :\   :lol
« Last Edit: 22 February 2015, 09:46:04 am by nick crisp »

Ian-man

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Re: chain and sprockets - dropping/raising teeth?
« Reply #16 on: 22 February 2015, 12:57:02 pm »
Maybe it's just that I fancied a bit more acceleration below 7000 revs. It don't like screaming the nuts off it even though I am able to.

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Re: chain and sprockets - dropping/raising teeth?
« Reply #17 on: 22 February 2015, 02:53:23 pm »
Hi Noggy - you've just about hit the nail on the head.


When I was racing a Proddie 400 in the 80's, there were some places where you either came into a corner screaming the engine in one gear, or bogging it in a higher gear - neither giving you the ability to get good drive through and out of the corner (especially true for Gerrards at Mallory Park). The answer was to either change gear (up or down) in the corner, which would upset the handling/grip, or change your sprockets - usually going up two teeth on the rear (to save time and cost I only had 2 spare rear sprockets, one with 2 teeth more, one with 3 teeth more - going to 4 teeth more meant the previously higher gear ratio was now the same as the previously lower ratio) so that you get the revs matched to corner entry speed to let you gave a constant drive through the corner. Changing the front sprocket was a lot more time consuming and the change for a single tooth extra/less was proportionally bigger than a couple of teeth on the back - so I never bothered with that.


To be honest, in road riding, I've never found the need to have my revs so precisely matched to corner entry speed, as I'm never short of drive out a corner - thesedays not on the Fazer 1000, or the Aprilia RSV, and certainly not on the FJ 1200 - so that's why personally I think it's a waste of money.


But, then again, maybe I'm the old dog that can't/wont learn a new trick.

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Re: chain and sprockets - dropping/raising teeth?
« Reply #18 on: 22 February 2015, 04:34:38 pm »
i dropped one on the the front and am happy with the difference it made sure it revs a little higher through the gears but i dont mind that although on motorways i sometimes find myself looking for another gear ,but its a cheap simple mod you can always change back again ,i for one like the extra excelleration and it still made 133 horses recently but that is with the full monty jobby               ,keep us posted on how it suits u if u go with it  :faz
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