Final Drive Ratio Alteration

[Das Autos]

Our team just had a problem because the clearance between our Sprocket and the Floor Pan, which seemed perfectly OK on CATIA, turned out to be too less. So we're having to switch from a 16/56 teeth sprocket, to a 14/52 teeth one.
I was hoping on getting some guidance as to whether it is likely to have any adverse effects in terms of the torque from the engine
Any help appreciated. Thanks

[Das Autos]

Our team just had a problem because the clearance between our Sprocket and the Floor Pan, which seemed perfectly OK on CATIA, turned out to be too less. So we're having to switch from a 16/56 teeth sprocket, to a 14/52 teeth one.
I was hoping on getting some guidance as to whether it is likely to have any adverse effects in terms of the torque from the engine
Any help appreciated. Thanks

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Das Autos:
Our team just had a problem because the clearance between our Sprocket and the Floor Pan, which seemed perfectly OK on CATIA, turned out to be too less. So we're having to switch from a 16/56 teeth sprocket, to a 14/52 teeth one.
I was hoping on getting some guidance as to whether it is likely to have any adverse effects in terms of the torque from the engine
Any help appreciated. Thanks </div></BLOCKQUOTE>
If the gear ratio is about the same, you won't notice a difference. The main problem with using smaller sprockets is the chain skipping teeth, but you should still be fine with 14/52, assuming the sprockets aren't right next to each other. I'm not sure if there are any significant differences in friction between the two setups, though.

[Luniz]

I'd suggest running 15/52 instead when this is possible.
Reasons:<UL TYPE=SQUARE>1.) The Ratio changes from 1:3.5 to 1:3.47 instead of 1:3.7 when using 14/52
2.) When running pair numbers of teeth on the two sprockets, the chain will wear unevenly, because the same chainlink will always meet the same tooth on the sprocket. In using on pair/one impair, the chain "rotates" through the teeth.[/list]

[A Richards]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Luniz:

2.) When running pair numbers of teeth on the two sprockets, the chain will wear unevenly, because the same chainlink will always meet the same tooth on the sprocket. In using on pair/one impair, the chain "rotates" through the teeth. </div></BLOCKQUOTE>

I feel as though i've taken the chain off our SAE car more times than its been driven. Im sure that should be sufficent for rotating it. Unless you do 1000's of km's testing your never going to wear out a chain and sprocket anyway so I really wouldn't take it into consideration.

Interesting arguement though. Haven't heard that one before.

[Das Autos]

In all honesty, we're cutting it really fine, so we're unikely to enough testing time. Although I suppose every team says the same thing. So I don't think the chain should get a chance to wear.

The thing is, we dont have the facilities to machine the sprocket ourselves, and it is really hard to get it made. Also, we are in possession of a 14 teeth one already, so we'll just have to go ahead and use it I guess. However, I'll definitely keep the pair/impair theory in my mind for next year. Thanks for that.

And thanks everyone, for the prompt replies.

[Luniz]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by A Richards:

I feel as though i've taken the chain off our SAE car more times than its been driven. Im sure that should be sufficent for rotating it. Unless you do 1000's of km's testing your never going to wear out a chain and sprocket anyway so I really wouldn't take it into consideration.

Interesting arguement though. Haven't heard that one before. </div></BLOCKQUOTE>

As the mentioned method is common practice in designing a chein drive, I suspect it could also be quite a good idea for design judging...

But anyway, if you don't have the opportunity of using a 15t sprocket, then I guess you'll just have to stick to what you got

[Thrainer]

To answer the original question, YES, this will affect the driving performance of the car by giving considerably more torque and less RPM, resulting in more gear shifts.
We went from 13 to 12 teeth last year and it was noticable.