What is the point of changing a sprocket?

jpickup · Post by **jpickup** » Fri Aug 20, 2004 12:28 pm

I've often wondered about this. They way I see it, say you wanted better acceleration then you would put on a smaller front (or bigger rear). This would then have the same effect as throwing away your 6th gear and giving you a shorter gear before 1st, i.e. the only difference is in your new first gear which you use for maybe a second. Doesn't seem worth it.

What am I missing?

(I doubt that going the other way for increased top speed would work either as you just wouldn't have the power in the 'new 7th gear').

iggy1966 · Post by **iggy1966** » Fri Aug 20, 2004 1:52 pm

The only thing that I can say on this is... it is worth it!!

I have fitted a 15 t front and the bike is transformed, it pulls cleaner through all of the gears, it picks up better when in a higher gear and is an absolute blast to ride, it pulls out of corners like a demented rhino all for the sum of Â£19 and about 10 mins work.

Out of all the mods I have done to my storm this is by far the best and most significant improvement to it.

vtrsteve · Post by **vtrsteve** » Fri Aug 20, 2004 2:01 pm

The biggest reason for a 15t on a storm is that it makes it far easier round town keeping the revs a tad higher so you don't need to drop between 1st and 2nd all the time.

SideSwipe · Post by **SideSwipe** » Fri Aug 20, 2004 4:37 pm

Though changing the gearing on the front sprocket will effect chain life.

Stormin Ben · Post by **Stormin Ben** » Fri Aug 20, 2004 5:05 pm

Physics lesson warning
Its all to do with torque, which is force times distance from pivot its applied
The force from the engine stays the same but the bigger rear sprocket means that more torque is applied to the rear wheel

Basically changing sprocket is not as drastic as the jump between gears. Think of 2nd gear being more useable and you're getting close.
The difference is only about 7% so if you're in 2nd on a stock bike and its doing 3000 revs, with a 15t front it'll be doing 3200.
Doesn't sound like much but that difference could be 4-5 horsepower. Which you would notice

Ben

STEVESTORM · Post by **STEVESTORM** » Fri Aug 20, 2004 9:45 pm

I have just done 15 t front and 45 rear. The bike will now outrun anything!!!. Tops out at 120 and revs higher but fun is infinite - total cost (DIY) Â£ 160 incl 2 x sprockets plus DID Heavy chain

Bink · Post by **Bink** » Sat Aug 21, 2004 3:50 pm

Steve/Ben,

You seem to be in the know/experienced on this topic.
When changing from standard sprocket sizes ... does it affect the chain lenght? (i.e. more links required then the standard 102 with a 45' rear)

Stormin Ben · Post by **Stormin Ben** » Sat Aug 21, 2004 5:26 pm

You can get a 2 tooth bigger rear on with the standard length chain.

Plus points: Shortens the wheelbase so it turns better and wheelies easier (or would if I was any good!!)
Negatives: Standard road tyres are fine but I've had 2 sets of track tyres that wouldn't fit with the hugger (208GP's and Rennsports)

15tooth front is also fine with standard chain
Plus points: cheaper than a rear sprocket
Negatives: Lengthens wheelbase so opposite of above. 15t is getting a bit small for a chain to go round comfortably. Its not gonna kill it but it could reduce the life due to the fact its having to turn a sharper radius corner

Ben

Fireman on a Storm · Post by **Fireman on a Storm** » Sat Aug 21, 2004 5:39 pm

What's the standard gearing 16 front and what rear?

vtrsteve · Post by **vtrsteve** » Sat Aug 21, 2004 8:35 pm

41t on the back

RAINMAKER · Post by **RAINMAKER** » Sat Aug 21, 2004 11:16 pm

So on balance if I was to only change the rear sprocket what would be the best to get.......how many teeth, whats a good make?

Stormin Ben · Post by **Stormin Ben** » Sun Aug 22, 2004 1:27 am

43 tooth rear then.
B&C express do Renthals cheap, but what you go for depends on what you want.
Colour, lightness, etc its up to you

Ben

RAINMAKER · Post by **RAINMAKER** » Sun Aug 22, 2004 4:23 am

cheers Ben......think I'll order one.
Any advice on chains ?

Paul.

Stratman · Post by **Stratman** » Sun Aug 22, 2004 8:32 am

I'm thinking that the 43 rear may be worth a try from what I've read - do you have to change both sprockets and chain together or can I just change the rear sprocket and keep the existing chain, which is OK?

STEVESTORM · Post by **STEVESTORM** » Sun Aug 22, 2004 8:46 am

After fitting a 15t front and 45 rear I have used a 104 link X-Ring DID professional chain. The standard chain will accomodate 1 tooth change on the front or 2 on the rear. If you change both sprockets or go to a 45 rear then you will need a 104. It's always best to change sprockets and chains at the same time.

B+C express do Renthals in anodised bronze which looks good with gold chain.

Warning / Advice - My bike is now a 15 / 45 instead of stock 16 / 41. It is now 30mph short top end but will out accelerate anything including my mates ZX12R.

Its fun and short / medium journeys are spectacular but long distance isn't funny.

VTR1000.ORG

What is the point of changing a sprocket?

What is the point of changing a sprocket?

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