sprocket info needed

[yooperman]

i bought and installed my new tires, on my 86 kawasaki tecate 3. i put 18's went down from the 22's that where on on it before.

now my question is, since i went to a smaller tire, do i need to change my gearing on it it has stock gearing on it right now. If i do need to change them, what should i switch to?

[bcredneck]

you lost top speed so you need a smaller back sprocket

[dcreel]

http://home.earthlink.net/~gellett/tecate3.htm

[yooperman]

dcreel that is neat little site you have there. i have never really had to mess around much with gearing on my other machines, so i am going at this a little bit blind lol. do you have a suggestion what i tooth sprocket i should go to with going from 22's down to 18's? i punched my info in the calculator thing, but didnt really understand what i was looking at lol. if the stock gearing is 13 tooh front 37 tooth rear, and i dropped 4 tire sizes. like bcredneck said i have to go smaller on the rear sprocket, do i leave the front sprocket alone and just change the rear?

what i am wondering/asking is how do i determine what size sprocket to go with do i subtract one tooth for every tire size changed do i go about it that way or is there a different method in figuring it out? i am not looking to create a super fast monster or anything like, just want to get it back to where its simular to the stock gearing, stock speed and so forth, its just gonna be a a regular rider, i am asking because i am gonna be changing and putting new chain and sprockets on the 86 tecate so i figured i would ask so i dont have to do trial and error with buying many new sprockets. my wife would have my hind end if i was buying stuff to check if it worked and spent all this money and only used it once and goes in the box with all the other parts lol. normally wouldnt say to much but ever since i bought this tecate, i have so much money going into it lol. dang things are expsensive compared to my honda's lol

I know there are quiet a few people who have these 18 inch trekker tires on there trikes, or have went to 18 in tires from bigger ones on there machines. could you guys give me some info on what size sprockets i should go with and if there is gonna be a new combonation size of sprockets. dont be shy let me know either on this thread or send me a PM i would greatly appreciate it

[Dirtcrasher]

Look, I'm no math geek but I'm sure someone could get it close to spot on with math.

The gearbox ratio remains the same, the gearing ratio is easy to check 37/13 = 2.846. Using that figure against the difference in circumference of the tire probably gives someone all they need.

22 x 3.1416 = 69.212 circumference. 18 x 3.1416 = 56.548 circumference. 69.212/56.548 = 1.223% loss.

2.846/1.223 = 2.327 or the new ratio.

35 rear/15 front = 2.333 or 33/14 = 2.357 I'd imagine those would be as close to stock as possible or I'm entirely wrong :lol:

Thats all I've got, I'm no math geek...

And remember that 18" tires are for very quick speeds, not top speeds and used primarily for racing which uses only a partial gearbox so many guys might just run a 35/13 - I wouldn't run a sprocket smaller than 13.

I'm trying bud!! :beer

[SWIGIN]

The rule of thumb we always used back in the 80s was for every 2'' of tire you lose in the rear you go up 1 tooth on the front sprocket. Since you lost 4'' I'd go up 2 teeth on the front sprocket.

You can then fine tune it with a different tooth rear sprocket.

[hang&rattle]

I have the same tires on my 85'. Here's what I came up with and will run when my +2 swinger is added. I also took out the 84' and 85' yesterday. The 84' with 20's and the 85' with the 18's. What's needed is more top end. Fortunately the Tecate is close geared and low. With the 18's you'll get there slightly quicker and being the Tecate is low geared, you won't loose much quickness with higher gearing. 15/38 gives you a 6o.37 mph top speed with a stock motor and 18" tires. My 85' has a low end pipe and a low to mid carb & Wiseco piston, so I don't lose qickness and gain in top speed. The sprockets are front:http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=330451976135&ssPageName=STRK:MEWAX:IT. and http://www.cheapcycleparts.com/products/28100-jt-sprockets-jtr1478-38-sprockets-jt-rear-sprocket-38t for the rear.

[Ironbnder]

I would say it is fast enough as is. The smaller tires will give you that pep to do wheeles and power slides and looks cool. You to old to worry about top end. Besides when we ride, my R will just be that much faster! :D