Sprocket Sizes vs 525 Chain Lengths
 

Dear All

Can anyone advise me of the following, without upsetting wheelbase/ride height outside of Ducati recommendations:

1. Maximum rear sprocket size with standard chain and 14T front
2. Assuming I stick with a 14T front, the steps in chain length vs. rear sprocket size

I used to run my race Mille at 15/44 (0.34) or 15/46 (0.326), which was fantastic for acceleration and actually more manageable than you'd think for short circuit work, being able to keep up with R1's and Blades. At the minute my 998S is only 14/36 (0.388) and it really feels like it's straining to unleash good acceleration on short circuits against low-geared 750's and 900's.

Any definitive advice would be welcome.

I posted a gearing formula a while back it works out the chain lenght /sprocket sizes , depneding on which way you use the formula
It Might help you !:D

I use DID 630 on my jota, real size chain !

WTF: Take a ride height measurement first with the axle at the nominal 4:30 position. Then reset the ride height after the chain freeplay is set to 25-35 mm.

An eccentric adjustment is always needed to adjust freeplay after a sprocket change so wheelbase and ride height will always change somewhat. The following chain lengths will place the axle about 4-5 o'clock.

1. 14/38

2.
14/36 (2.57) 94-links (525HV-916SP)
14/37 (2.64) 94-links (520VL4-748SP,748SPS)
14/38 (2.71) 94-links (520VL4-748)
14/39 (2.79) 94 or 96-links
14/40 (2.86) 96-links
14/41 (2.93) 96-links
14/42 (3.00) 96-links
14/43 (3.07) 96 or 98-links
14/44 (3.14) 98-links
14/45 (3.21) 98-links
14/46 (3.29) 98-links
14/47 (3.36) 98 or 100-links
14/48 (3.43) 100-links

15/36 (2.40) 94-links (525HV-916, 996)
15/38 (2.53) 94 or 96-links
15/39 (2.60) 96-links
15/40 (2.66) 96-links
15/41 (2.73) 96-links
15/42 (2.80) 96 or 98-links
15/43 (2.87) 98-links
15/44 (2.93) 98-links
15/45 (3.00) 98-links
15/46 (3.07) 98 or 100-Links
15/47 (3.13) 100-links
15/48 (3.20) 100-links

[Edited on 12-1-2003 by Shazaam!]

Thanks once again, Shazaam. Just two questions:

Eccentric Position
I thought the "recommended" eccentric position was 6 or 7 o'clock - can you confirm 4 to 5 o'clock is the correct setting?

Chain Pitches
Am I right in interpreting from your list that a 14T front sprocket should only be used with a 520 chain? I use a 14T with a 525, so:
a) Is that a real problem?
b) Do the same chain lengths apply for 14T/525 as 14T/520, as outlined in your post? If not, could you please advise me of them?

Thanks in anticipation.

[Edited on 1-9-2003 by 998Addict]

It's 4-5 o'clock when viewed from the sprocket size.

A 525 chain is 5/8" between pins length wise as is a 520 chain and the 525 chain is 2.5/8" (5/16") wide between side plates which is also the sprocket width, where as the 520 chain is 2/8"(1/4") wide. All chains marked in this way refer in 1/8th of a inch to the chain size, ie 630 is 6/8 X 3/8 and a 530 is 5/8 X 3/8. but a 532 although it is 5/8 X 3/8 has larger diameter rollers than the 530 chain.

Felix can you do a chart like Shazaam's for the longer swingarm.
Only kidding worked it out for myself.

998addict i've been runing a 14th with a 525 chain on the race bike all the time I've had it with out any worries, I will soon be changing from a 94 link chain to a 96 link as the cocentric is to far forward when runing a 38th rear sprocket, but been putting it off in the hope of fitting a longer arm which would then require a 98 link chain

[Edited on 1-9-2003 by skidlids]

Shazaam / Skidlids (or others of infinite knowledge!)
 

Hi

Four questions on this thread, if you don't mind:

Unanswered question from my last post
Sorry if I'm being a bit dumb regarding Skidlids' post, but does this table hold true for a 14T/525 combination? i.e., would a 96 link chain accommodate a 14/39 combination for a 525?

Increasing chain length
I have spare links from the same manufacturer as my chain. Do I simply add these extra links using more than one soft link?

Reusing Soft Links
Is it permissible/advisable to reuse soft links?

54mm Termignoni System
When the eccentric is anywhere past 6 o'clock (180deg), the rear tyre makes contact with the downpipes. Is this normal? Does it mean I should add an extra link (making 97 in total) when doing my chain calculations?

Thanks all in anticipation.

Others will have differing opinions, but I would not recommend adding links to a chain with soft links. If the chain is too short, I would get a new chain. Soft links are definitely NOT resuable. Taking a risk in this area in order to safe a few bob, will pale in comparison to having to replace crank cases that got ripped up by a broken chain.

As far as I know the larger diameter down pipes were not meant for the standard length swinging arm, and it's not too surprising that the wheel could interfere. Aside from fitting the longer swinging arm or a smaller diameter downpipe, the only possibility is to see if other tyre makes have a slightly smaller circumference. Are you running a 180 or 190 tyre?

Only Use Riveted Links
 

First, to illustrate Felix's point about the consequences of using a soft link. Considered from just a safety point-of-view, I personally would only use a riveted link on a 998 chain. If you don't have the proper tools to install (one or more) riveted links, have your dealer do it.



To address your questions:

A 525 and a 520 chain (having the same number of links) have the same length, i.e. the same distance between links, but because they have different widths, they need different width sprockets.

If your rear tyre is contacting the larger downpipes you need to add two more links (total 98) to the chain to allow the eccentric to move the axle toward the rear of the bike away from the pipes. Chains always have an even number of links (alternating inner-outer plates.) Remember to record your ride height at the 4:30 position first.