I have a trailblazer 250 with an RCR stage 1 kit on it. The other day i shredded some teeth off my front sprocket so i have to change that......while im at im gona change the rear spreocket also. my question is if i increase the rear sprocket 1 or 2 teeth will i loose that much top end or will it not be too noticable?

Mustang

 

i beleave you will gain a little by going up 1 or 2 teeth.

 

Without calculating it, I can't say how much you will lose. Not much I'm sure since you're only adding 1 or 2 teeth. If absolute top speed isn't that important to you, I'd say go larger and not worry about it. Obviously you're after better acceleration, which I'm sure you'll notice with this change.

BTW, might consider checking your chain for stretch. A worn chain will wear down new sprockets in short order, depending upon how much you ride. If your chain has a couple of years of regular riding on it, I wouldn't even bother measuring it, just replace it.

Try these sites for calculating the difference. The first one needs your tire size as well as front and rear sprocket size and engine RPM.
The second one needs transmission gear ratio values to work. Good luck.


SIMPLE

COMPLEX

 

Thanks for the replies guys. i really like that site sheepdog it is great. yea i already have a new chain to put on cause i think that was the main problem.........thanks again

Mustang

 

Can't say if this is true, but I once read that 1 tooth on the front is worth 3 on the rear. They also said to run the biggest front gear you can and regear the rear because it is easier on your chain.

 

Bigger on rear, smaller on front = more low end

Lower on rear, bigger on front = more top end

1 tooth on front = 2t on rear

Most trail blazers have a 38t rear and 11t front which = a 3.45 final gear ratio. Some came with a 12t front and 40t rear which gave it a 3.50 gear ratio.

I dont think you can go smaller than an 11t on the front. You can however go up to a 42t max on rear. For this you will have to add links.

38t rear/11t front=3.45
40t rear/11t front=3.63
42t rear/11t front=3.81

 

yea you guys are right. i had my thinking reversed. i always put a bigger gear on bottom of my sled. short track racing.

 

I went out and counted mine and it has 11/36........this is because it was built in the later half of 2001..... the early months of 2001 came with 11/38. so if i get the 38 rear sprocket is it a good assumption to loose 3-5 mph on top end........and doese anyone have any idea why they would regear the machine half way through the year

 

Not sure why they changed. There is a $10 difference between the 36t and 38t sproket.