Setting Chain length and tension

[Boogeyman]

if you read Poops build, he has the remedy for this...He can adjust the fender and the chain to keep the fender and tire centered on each other...

[Boogeyman]

I'm going to swingarm mount my rear fender in the near future and this has been on my mind as well...

[CloudDiver]

Originally Posted by Boogeyman

if you read Poops build, he has the remedy for this...He can adjust the fender and the chain to keep the fender and tire centered on each other...

Thanks for the tip... I read the whole whole thread, Poop has some real talent! The heim joints are an incredible idea, but I'm not sure how it will work on my CFL. I know i'd probably have to ditch my web struts, and I like those... I'm going to take a good hard look at the frame/fender tonight.
I have an old, but unused chain from another chop I have (a 79 sporty in a Paughco frame). The shop that set up the rear fender lost the master link, so I picked up a replacement link today and I'm going to size that chain for mock up before I set up my Renthal chain.

I have some time to think about the different ways I could mount the fender. For now I'm still waiting on anyone who has a measurement of how far back their axle moved after chain stretch...

[RedWings]

As I said before, ALL chains stretch! maybe one chain will stretch faster than another but they ALL stretch to the max eventually. There is no doubt in my mind that you'll eventually use the whole slot in the axle unless the bike is a trailer model.

[axeychrome]

your advantage is you have a rigid, right? don't need as much clearance on a rigid as the swingarm can't bounce up and down like on a softail. definitely start as close as you can to the front. last rigid i built, i just made the fender stop at 12 o'clock so wouldn't be as noticeable when the tire is further back.

[CloudDiver]

I found this thread from wayyyy back to 2007, some good info here;

Setting up Rear Axle

My axle (with my test chain installed and tensioned) looks the same as the pic posted on this thread, just foreward of center. In the thread he says James from WCC said to mount the fender with the axle dead center. This makes sense because you have a bit more axle adjustment left to tighten up after chain stretch. I'm leaning to going this route.

A few things on my mind;
- I could still install a Troy Fab chain tensioner... anyone have experience with these?
- I could make my fender mount holes slightly oval to allow for up to 1/4 " to move the fender back, but that won't work with web fender struts.
- I think I'm going to pass on the washers welded to my fender and go with the leather washers I got from LowBrow.
- I could take one more link out of my Renthal R4 SRS than I have out of my mock up chain, but even one link could be too tight to even get on with axle all the way foreward.
- On second thought I can still do welded fender washers since the oval hole idea is worthless when using fender struts...
- I could say fuck it all, set my renthal chain to the same length as my mock up chain, mount my fender with the axle dead center, and weld the tab for the chain tensioner but not install it until I need it, even if the chain never stretches that far.

One way or the other I have all week to lose sleep over it... I had to order a Motion Pro PBR chain tool becuse I need a chian tool that will do Quad Stake Rivits and it wont get here until Friday.
I think with a chain tensioner I can set my rear fender dead center and never have to worry about moving the axle any farther back. Without the tensioner I think I'm still in good shape to start with an axle slightly foreward of center that will settle back to center but not further, and if it does I can modify the fender mounts enough to adjust for the movement, only if I don't weld washers to the fender... or get a new f'ing chain...

[kxmotox247]

I posted this before:
Mounting Rear Fender and Chain Stretch

I mounted mine tight into the fender to allow for stretch. I don't have shit for miles yet since I'm waiting for a title on it. I think it'll work out. Buy a good quality chain and adjustments will be minimal.

[foggdog]

Originally Posted by CloudDiver

With all the work I've been doing on my rear fender I want to get to breaking my chain to the right length and rivet on the master link. My drive line is already spaced and good to go.

Before I go any further, look at this and tell me if I have it backwards. i feel like a real dummy for not remembering if this is the correct way.



Does lobe face back like this, or should it be foreward? I have the set screw (axle adjuster) driven in to where the secondary set screw sits flush in front. Not much thread left to drive it back any further.

Is the idea to have the axle end up somewhat center in the iron cross, or a little foreward, or behind it?

Is that a new chain ? Looks like its got surface rust on it around the pins on the links. If its a new o-ring, there should be all kinds of grease on that thing.

[CloudDiver]

Originally Posted by foggdog

Is that a new chain ? Looks like its got surface rust on it around the pins on the links. If its a new o-ring, there should be all kinds of grease on that thing.

In that pic no, not a new chain... old but never used. That was the chain from my 79 Sporty chop that Moreland Choppers lost the master link to. I have cut that chain to length for CFL for testing, but I have a brand new Renthal R4 SRS 530 120 link still in the plastic.

[CloudDiver]

I got this response from Renthal UK on what to expect for chain stretch; very good answer with some math to figure exact amount of axle movement. General rule of thumb seem to be expect 1% of elongation over chain life... I know this is for Renthal chains but I think it would be safe to use the same math on other high quality chains like DID, EK, etc.

"Thank you for your enquiry concerning Renthal 530 chain.

Yes, our chains are pre stretched and we agree there will be a slight but minimal elongation during chain run-in or break –in.

The maximum acceptable elongation for a Renthal SRS chain over the chain’s entire life is 1%. You do not advise your chain length so I cannot calculate this for you. However if you measure the distance from the centre of your gearbox output shaft to the centre of the rear wheel axle in the forward most position and multiply this by a factor of 1.01 you can establish the maximum acceptable “end of life” chain length.

A typical bike having a 120 link chain, a 14 tooth front and 46 tooth rear has gearbox output to axle centres of 28.125” on chain installation. At chain “end of life” the maximum movement of the spindle should be no more than .28125” or 7.144mm.

(120 links – (46/2)-(14/2))/2=45 links

[divide sprockets by 2 as approx. only half is engaged by the chain]

{divide remaining chain length by 2 as you have the lengths above and below the fixed swing arm}.
45 links x (5/8”)=28.125”

28.125” x 1.01 = 28.40625”

28.40625” - 28.125” = .28125”

.28125” x 25.4 =7.144mm

Renthal - We Build Championships

Trust this assists you with your enquiry.

Thanks

Kevin Gladstone

Renthal Ltd. (UK Office & Factory)

Bredbury Parkway

Bredbury

Stockport

Cheshire, SK6 2SN

[chopperfugger]

[CloudDiver]

Originally Posted by chopperfugger

Is this a link? I can't open it...

[Poop]

Originally Posted by CloudDiver

Is this a link? I can't open it...

two and a half, i think.

[chopperfugger]

it's a master link that I used - no rivets - you screw on the nuts till
they fail and break off. it works as good or better than rivets.

Hey Cloudiver -

I haven't been saying it - but it's been bothering me -
Are you mocking up your tranny / battery / fender / tire?
All together?
CFL's are tight between the tranny and the fender.

[Poop]

roger, i'm interested in that master link. any more info i can search on?