Chain and sprockets

Jolly Roger V4 said:

I must agree, Laguna Seca is a bit of a tosser track I have determined. Latte free zone for sure.

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just choose one of the many other world class tracks available in the USA.......er....COTA ....er...

Jolly Roger V4 said:

I must agree, Laguna Seca is a bit of a tosser track I have determined. Latte free zone for sure.

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Must be why I like it so much

SuperDomestique said:

I’m so confused. I thought you said you aren’t considering QC… And you inferred that you were overweight in your previous posts.

Also, per the Ducati workshop manual a final drive lifespan should be around 20k km (12k mi) with proper maintenance.

Chain elongation per manual is View attachment 51504

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I don't see why you would be confused and I'm not sure you really are confused. I did say that I wasn't going to consider a QC sprocket. People have been helpful and suggested that I should consider it... that's what happens in a discussion where you keep an open mind, having asked for relevant advice. Only an idiot starts with one point of view and refuses to consider others. I wouldn't ask questions if I wasn't interested in useful and relevant answers.

I didn't say or infer I was overweight - I said that I wasn't interested in losing weight myself... words matter and it could easily mean that I do not need to lose weight, hence I am not interested in doing so. It doesn't mean that of course, but it could. Also, if I do lose weight that doesn't mean I shouldn't also do the same with the bike - your statement infers that it would be better to spend money on gym membership to lose weight but that wouldn't mean that I cannot also lose weight from the bike. I've no idea why people phrase things as if you can only spend money on one thing... It really does seem that you are looking for arguments.

The chain elongation information is useful. I'm not sure what the original chain length is and therefore how much is the maximum stretch advised. Certainly I would want to change it before getting to that point.

spooky said:

I'm not sure what the original chain length is and therefore how much is the maximum stretch advised.

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Oy vey… 25.65 cm is the max stretch advised by Ducati and any 5xx pitch chain. It’s literally written right there. Words matter.

If you want to know the original length, Google is your friend

andyb said:

I heard it may well become a housing estate?

I agree its a fantastic world renowned circuit steeped in history.....obviously its no chuckwalla.....

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That's not what I have heard and I'm local and know some people. That doesn't mean it couldn't become a housing estate of course but big housing estates are less common here than in the UK.

We will see what investment is made over the next year or two and that could indicate whether the stated plans to get MotoGP back are real. I hope so.

The circuit has such a nice flow to it and there's plenty of room for the occasional mistake, avoiding an over-ambitious rider, etc. I love the place.

I think you went there with No Limits earlier this year? I wanted to get there but couldn't - hopefully I'll see you there this year. I recommend Most as well - huge fun and very technical. I've no idea how Rae set the time he set there this year.

There are go no-go tools you can use to measure chain stretch. There is a Ducati branded version of this same type of tool but its almost $200.

Amazon

SuperDomestique said:

Oy vey… 25.65 cm is the max stretch advised by Ducati and any 5xx pitch chain. It’s literally written right there. Words matter.

If you want to know the original length, Google is your friend

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Good grief...

It says 'maximum admissible length'. Admissible means acceptable. Based on the numbers, which I had not paid attention to (not words - numbers) then I guess that something got lost in translation or there is a heading missing and it's referring to the length increase. I read the column heading and presumed it meant chain length. Not the end of the world but enjoy.

Moving the hub around 10cm back for that much stretch seems a lot to me.

Google is most certainly not my friend - never even bought me a pint.

bp_SFV4 said:

There are go no-go tools you can use to measure chain stretch. There is a Ducati branded version of this same type of tool but its almost $200.

Amazon

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Interesting. Is there not a standard distance between the sprocket centres that you'd be looking for to maintain a certain wheelbase and as you move the hub back to set chain slack as it stretches then there would be a maximum you'd want to go before you're changing the wheelbase more than you want, or does it not work like that?

You'd need a ride height tool to determine effect on geometry from chain adjustments.

I'd speculate you'd have to make some significant adjustments to the eccentric hub before there'd be a significant change to geometry. Something more likely to exist with a change to final drive ratio rather than chain stretch.

bp_SFV4 said:

You'd need a ride height tool to determine effect on geometry from chain adjustments.

I'd speculate you'd have to make some significant adjustments to the eccentric hub before there'd be a significant change to geometry. Something more likely to exist with a change to final drive ratio rather than chain stretch.

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Good to know.

Thanks for the useful info.

bp_SFV4 said:

You'd need a ride height tool to determine effect on geometry from chain adjustments.

I'd speculate you'd have to make some significant adjustments to the eccentric hub before there'd be a significant change to geometry. Something more likely to exist with a change to final drive ratio rather than chain stretch.

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Au contraire,....rotating the rear eccentric from min to max length puts the ride height through a difference of 12mm so where ever your adjustment ends up means it could change. As its rotated clockwise it goes up then down as the spindle goes over the 12 o clock position.

changing from a 41 rear sprocket to a 42 added 3mm rear ride height and I have a longer chain length.

that's why a ride height tool is essential but you also need the facility to alter/reset ....... almost like we have been here before!

andyb said:

Au contraire,....rotating the rear eccentric from min to max length puts the ride height through a difference of 12mm so where ever your adjustment ends up means it could change. As its rotated clockwise it goes up then down as the spindle goes over the 12 o clock position.

changing from a 41 rear sprocket to a 42 added 3mm rear ride height and I have a longer chain length.

that's why a ride height tool is essential but you also need the facility to alter/reset ....... almost like we have been here before!

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Interesting to hear measured data.

Did you notice any difference in handling from that 3mm difference in rear ride height?

spooky said:

Good grief...

It says 'maximum admissible length'. Admissible means acceptable. Based on the numbers, which I had not paid attention to (not words - numbers) then I guess that something got lost in translation or there is a heading missing and it's referring to the length increase. I read the column heading and presumed it meant chain length. Not the end of the world but enjoy.

Moving the hub around 10cm back for that much stretch seems a lot to me.

Google is most certainly not my friend - never even bought me a pint.

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If you don’t know how to measure chain stretch then why were you commenting that your chain was out of spec in your previous posts? 5xx pitch chains are nominally 25.4 cm between 16 pins. So you have 2.5 mm of stretch to work with (which is a lot). If your chain is out of spec with only 1200 km + 12 track days, you’ve got bigger problems than switching to lightweight sprockets.

SuperDomestique said:

If you don’t know how to measure chain stretch then why were you commenting that your chain was out of spec in your previous posts? 5xx pitch chains are nominally 25.4 cm between 16 pins. So you have 2.5 mm of stretch to work with (which is a lot). If your chain is out of spec with only 1200 km + 12 track days, you’ve got bigger problems than switching to lightweight sprockets.

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I didn’t complain that my chain was out of specification.

Please stop trying to finding things to argue about.

spooky said:

I didn’t complain that my chain was out of specification.

Please stop trying to finding things to argue about.

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spooky said:

OEM chain had stretched significantly, was previously adjusted and needs adjusting again. It’s done 1,200km on road and 12 days on track and I want to change it.

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spooky said:

Moving the hub around 10cm back for that much stretch seems a lot to me.

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And moving the eccentric hub 10 cm seems not possible. I have 5600 km on my bike and I’ve moved the hub clockwise about 2 mm (degrees would be a better measure but I digress).

spooky said:

Interesting to hear measured data.

Did you notice any difference in handling from that 3mm difference in rear ride height?

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I wouldn't confess to being that good or that 3mm will be different. But I have experienced changing it slightly more and the effect on the feel of the bike especially if you alter the front too. that's why its good to have a datum number.

At Brno we had 3 x 22 base bikes and compared numbers and differences . That was a great real time exercise in getting towards a set of numbers that felt good but also what felt bad or wrong across 3 different riders, styles and ability levels.

SuperDomestique said:

And moving the eccentric hub 10 cm seems not possible. I have 5600 km on my bike and I’ve moved the hub clockwise about 2 mm (degrees would be a better measure but I digress).

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I've no idea if it's possible or not - I just took under half of the total stretch figure given. Is it important or is it just another example of trying to score points. I've no idea what bike or chain you use, how you've ridden those km, etc, so I've no idea what relevance your stated adjustments have to my situation. I didn't measure how far I had moved the hub but it certainly seemed like more than that. I did notice that I felt like I was more on tip-toe after adjusting the slack though.

I’m running EK 3DGP520 chain with Superlite rear quick-change aluminum rear sprocket & steel front from Drive Systems on my ‘21 SP. Use all titanium hardware and there is a significant weight savings over stock. I run the oem rubber/steel cush drives rather than the poly versions for the better lash cushioning. I’m also running 15/42 gearing for my purposes. The bike touches the first flash of impending rev limit at 182mph via gps with the speedo long into - - -. It will likely do several more mph before actual rev cut, but 182 is good for my purpose.

andyb said:

on track mileage you won't be changing due to wear very often but its cheap enough to change to suit a purpose.

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Did you see the picture of the sprocket teeth that I posted earlier? Is that what you would expect for the km done? It looks quite squared off to me but everything looks bad when zoomed in a bit. I’ve no idea what it should look like or if that’s perfectly ok but I fancy changing to lighter sprockets when I change the chain regardless, on the basis of ‘why not’. I’d be interested to hear what you think though.

You mentioned that different sprockets requires different chain lengths. Does this mean that if I decide to go the QC route and try different gearings then I need to put a new chain on each time? Presumably that’s more likely for some combinations than others?

A QC sprocket might encourage me to try different gearing, which could be interesting, but the key to doing that at an early stage of my personal development would be how easy it is to do it. If something’s a pain in the arse to do then it’s less likely to be done (at least as far as I’m concerned - the last thing I want to do on a track day is miss sessions while buggering about with the bike).

on a worn sprocket the teeth tend to go hook shaped.....didnt think yours had

so if you add an extra couple of links you can just use the same chain but in a different part of the adjustment FWIW chains generally come in 120 links and you cut it down to what you require..

once proficient it doesn't take 10 mins to slacken the chain, swap the sprocket and readjust the chain. its not like you would be doing it every session. fit the QR with the std size rear sprocket when you are ready get a different size try it...