Changing ratios - Rear Sprockets
 

Hi all Im thinking of changing the sprockets im running and thought id ask the question to see what the masses are running.

The Duke is fitted with a DID ERV 520 chain, Renthal 15T front and 38T rear with Renthal sprocket carrier.

The chain is mint and as its due for a service down at JHP in January, fancied changing the cogs. Bearing in mind ive heard if you go up too much you have to change the chain, (DONT WANT TO DO THAT)

In France this year with this set up I had 170mph showing on the clock. Im not bothered about the top end as in this country id end up inside.

Any suggestions

I went up 3 on the rear, the same as dropping to a 14 on the front. Made the bike much nicer to ride. Did fit a longer chain though.

ratios
 

So what size sprockets are you running then on the front and rear

IF Martin is talking about his R then its 15 front 36 rear originally so now its
15 front 39 rear
I have 15 F and 38 R with the same size chain
On the bigger bikes its better, so Ive been told to go more at the rear as it causes less stress

i run a 14 / 37, still overtakes a guy on his R1 flat out in top, and pulls away sweetly.

there are some who say not to go with the smaller front as it turns the cahn tighter, but ive never had any problems with it. chain life seems fine etc

ratio
 

So if I go a tooth smaller on the front to 14T and keep the 38T rear I should see a difference... yeah ?

Oh yes !!!!!!!!!!!!!! Talon make a 13 front, but it runs too close to the swinging arm. 14 will be fine :)

If you do go that way let me know how it is as now I am running just a
15 front and 38 back, so curious how much of a difference it will be, if that front wheel comes up

ratio
 

Brill final question, how much for Renthal 14T front sprocket

£17.32+vat

ratios
 

Thanks for that. All the best to you all.

There's a "sweet spot" - around 4,600 RPM @120Km/hr in 6th gear for liter displacement superbikes, a little higher for 74X's. Obviously, faster tracks will require rear sprockets with fewer teeth, slower tracks more teeth (and possibly longer chains.)

I strongly recommended NOT changing the stock front sprocket or chain size for safety reasons. Just my opinion.

Shazaam!, I used this very chart that you kindly provided earlier in the year when I changed my gearing. Only problem being the listed sprockets for the 996R are incorrect. They have a 36 tooth rear as standard. Apart from that its a great bit of info.

Happy New Year! :)

Thanks Martin. The data's been corrected above.

Dear Shazaam

Table not visible just a little red cross in a white box. Could you kindly e-mail

many thanks

Tim

From memory i'm on 15 38 on my 6R.

I did briefly try a 14 tooth front to test the results before investing in a rentahl rear sprocket carrier. Larger rear sprocket for same results, less stress on chain and safety reasons Shazaam has expressed.

Front wheel comes up very easy:D