My TY175 is currently running 52 teeth rear and 13 teeth front. 4:1 ratio. I know standard is 51/13.

I am happy with how the bike goes for the type of riding I do (twinshock trials).

My sprockets are getting near the end and I am wondering if I replace them with a 48 teeth rear and 12 teeth front (still 4:1 ratio) will the shorter chain and wheelbase make any noticeable difference?

My guess is that the few links less in the chain won't be noticeable?

Shorter wheelbase may affect things but how?

Sprocket wear will be greater due to less teeth to share the work?

Is a 48T available anyway?

What are you running on yours?

Am I over thinking this?

Comments, advice, etc appreciated.

Cheers.

Edited April 1, 200818 yr by kimpybugalugs

Sorry mate, I've read your post several times and am struggling to understand what you are trying to achieve. If you are happy with the current gearing why not replace like with like? What will you achieve by just going for smaller sprockets?

As for wheel base effect, changing sprocket sizes will not affect the wheelbase. Your engine output shaft position stays constant and the rear wheel spindle is constrained by the swinging arm slots-i.e. NO change

So I guess the answer is YES you are overthinking!!

Thanks for your comments.

I didn't mention the weight saving - smaller sprockets=less metal and less links in the chain therefore less weight.

With the hundred or so grams that'll save it means I can have a couple of extra Mars bars and the bike will still perform as well.

All of you kidding aside, you'll probably want to focus on getting the TY in top shape before worrying about a few hundred grams here or there.

Depending on how long your shockies are, you may increase the rate that you wear out the swingarm pivot protector by fitting smaller diameter sprockets. If you have 340mm or longer shockies, you will definitely be compromising the clearance at the swingarm pivot if you use smaller sprockets.

The smaller front sprocket is also harder on the chain so you may go through sprockets and chains quicker too.

If you had one of the old bikes that didn't have much primary reduction and required a dinner-plate sized rear sprocket then going to a smaller rear sprocket might be of use. I can recall people bashing those kinds of big sprockets on rocks and throwing a chain.

cheers,

Michael

What was yesterdays date again????!!!.

All of you kidding aside, you'll probably want to focus on getting the TY in top shape before worrying about a few hundred grams here or there.

Good advice and I'm working on it.

As for the ratio thing I'll stick with 52/13.

Probably more important to shed a few kilos off me - I think the bike would appreciate it.

ratio should not affect wheelbase, but chain length will as it puts the axled forward or back in the swing arm. I have heard of people add/subtrtact two links so the axle is in front or rear of adjusting slot to gain an inch of change. I would certainly never be able to tell the difference, and I want as much adjustment as possible.

Smaller sprockets have less chain speed, but more chain pull, for the same required wheel torque loads. Minor issues, no significance.

I dropped down on ratio, and ride most sections in second gear now. don't recall raatio, I can check, but sounds you are happy with what you have.

just a minor deal, but better to have a prime number on one of the sprockets, or at least an odd ratio. so you don't have an exact 4:1 ratio. The same chains and sprockets teeh match up over and over with exact ratios. More of an issue with gear teeth, they almost never have exact ratios as the teeth mesh directly. Always better to have teeth matching adifferent tooth each cycle around. Like I said, theory only, don't worry about it if you like what you have.

there, lots of tidbits mostly meaningless to your question.

k