question on sprockets

[cbcanada]

i have a 15t front sprocket which makes the bike rev up faster . but some people keep the front stock and change the back sprocket and the bike revs faster.

is there a difference in changing one or the other?

[Higgins13]

Here are the pros and cons of each.

Down in front:
Pros:
Less money up front

Cons:
Smaller sprocket means more revolutions and will eat chain and rear sprocket much faster.

Up in rear:
Pros
Will not wear chain any more the regular sprockets

Cons:
More up front money

Just remeber Going down 1 tooth on the front is the equivalent of going up 3 in the back. This means a 15t front sprocket will in theory have the same effect as a 42t rear sprocket.

If changing your sprockets I would recommend doing only the rear a replacing the front with a stock 16t at the same time as well as a new chain. You can purchase all 3 on eBay for 125 or so.

[cbcanada]

Here are the pros and cons of each.

Down in front:
Pros:
Less money up front

Cons:
Smaller sprocket means more revolutions and will eat chain and rear sprocket much faster.

Up in rear:
Pros
Will not wear chain any more the regular sprockets

Cons:
More up front money

Just remeber Going down 1 tooth on the front is the equivalent of going up 3 in the back. This means a 15t front sprocket will in theory have the same effect as a 42t rear sprocket.

If changing your sprockets I would recommend doing only the rear a replacing the front with a stock 16t at the same time as well as a new chain. You can purchase all 3 on eBay for 125 or so.

i have 15t front. if i went up size with the back spricket and put my old 16t back is that okay? or a new front and new chain are a must?

[Shepa]

When using bigger rear sprockets, maybe the chain length could present a problem.

But, there's always www.gearingcommander.com so you can calculate any ratio you want, and much more.


Sent from my toilet seat using HTC FartPhone

[Higgins13]

i have 15t front. if i went up size with the back spricket and put my old 16t back is that okay? or a new front and new chain are a must?

Like previous poster said your chain length may be to short when you add the larger rear sprocket. I am not familiar with the "gearing commander".

They way I look at it when you replace one do them all because if ether sprocket has any wear in it those wear marks will chew the new chain very quickly to the condition of the current chain and vice versa if yo only replace one sprocket the wear marks on chain will chew the new sprocket to the condition of the old one.

Here is the set I bought for my bike:
http://item.mobileweb.ebay.ca/viewitem?itemId=330763805573&index=0&nav=SEARCH&nid=42371907294

[gsJack]

A 42T rear should work with your 15T front and 110 link chain, would move the axle forward approx .35" from the stock 16/39T 110 link position. Easy enough to try the 16T at same time if you prefer that.

Center distances I've calculated:

http://gstwins.com/gsboard/index.php?topic=44849.msg502495#msg502495

I use Tsubaki calculator:

http://tsubaki.com.au/tsscs/chain_length.htm

[Higgins13]

I just found that once you factor in the shipping of buying two of those items you could get all 3 for same price in combo.

[cbcanada]

i am thinking of putting my old 16t back on and swapping the back to this used 45t rear i am getting. honna keep using my current chain

[Higgins13]

Good call going to Stock front. I hope your new chain fits!

[gsJack]

16/45T with 110 links would be a 24.675 center distance moving the axle forward about 1" from stock position.  Might fit with a well worn 110 link chain.   

i am thinking of putting my old 16t back on and swapping the back to this used 45t rear i am getting. honna keep using my current chain