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Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 9:29 am
by eithr
Something new to me. So, I have neglected to adjust the chain tension on my GT380 and now it needs it without question. Is the whole trick to this just loosen up the rear wheel and back it out a little until the chain has about 1/2 inch up and down play? All the while also keeping the chain/sprockets aligned?

Is there much of a trick to this or is it as simple as it sounds? This is basically the process for adjusting chain tension on my track bicycle... curious that it could be this simple.

I think I have about 4000 - 5000 miles on the current chain. How often should I need to make adjustments? How often should I expect to need to replace the chain?

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 9:39 am
by Craig380
The 380 has little pinch bolts across the open end of the swingarm, these need loosening as well as the main wheel spindle nut.

For setting the tension, I try and find the tightest spot on the chain (there's always some point with less free play than anywhere else), then take the bike off the stand and get a willing partner / wife / teenager to sit on the bike while I adjust the tension to about 3/4" free movement.

I count the "flats" on the adjuster nuts and just make sure I turn each by the same amount.

Mine had a heavy-duty chain on it when I bought it, it's done about 15,000 miles with minimal adjustment, although these are dry road miles. I keep it well lubed using spray-can chain grease.

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 3:33 pm
by Suzsmokeyallan
Another trick is to not slacken the axle nut off completely, and use the adjuster bolts to "pull" the wheel back under slight tension with the adjusters. You only get one chance at this so if you mess up and over adjust it, you will have to slacken the adjusters and move the axle forwards again and repeat the process.
Doing this loads the adjusters and takes out the freeplay in the axle to adjuster assembly.
If you do not have an x-ring chain its worth getting one of at least 8000psi tensile strength; after the first two settling in adjustments it will be good for many miles.
Its a good habit to get into by using the tip of your shoe to lift the chain up right behind the centre stand and see how much play it has when the bikes parked on the side stand.
Once you know how much it should deflect at the correct setting you can easily tell if an adjustment is due soon.

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 3:49 pm
by crash277
if you want to ensure enverything is snug put a rag in between your chain and sprocket at the top of the rear sprocket and spin your tire and the rag will stop the chain/wheel from spinning it will pull the rear tire assembly forward.

if you want to be really accurate, can buy an axle allignment tool. or i just found this video online. way cheaper then the tool my buddy got lol.

http://en.kendincos.net/video-tpppjpjf- ... gauge.html" onclick="window.open(this.href);return false;

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 5:22 pm
by two-stroke-brit
crash277 wrote:if you want to ensure enverything is snug put a rag in between your chain and sprocket at the top of the rear sprocket and spin your tire and the rag will stop the chain/wheel from spinning it will pull the rear tire assembly forward.

if you want to be really accurate, can buy an axle allignment tool. or i just found this video online. way cheaper then the tool my buddy got lol.

http://en.kendincos.net/video-tpppjpjf- ... gauge.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

thats a simple but effective home made gauge. :up:
thanks for posting

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 5:50 pm
by crash277
no problem. this question got me searching for an adjuster for my tool box. My buddy has one that is 2 rods with adjustable lockable cones one you put one through the axle and you put the other through the swing arm pivot. it gives you a high degree of accuracy because they stick out about 8" on eaither side of the bike. You adjust your chain and then measure each side and adjust the brake side till they are the same. I borrowed it a few times for my race bike but im a big fan of "you need to borrow a tool twice you should buy it"

Re: Dumb Question... Adjusting chain.

Posted: Fri Oct 29, 2010 9:39 pm
by tz375
That's a nice idea, but it only works if the frame and forks are absolutely perfect - but they rarely are. What that does is to position the wheel at the right distance from the swingarm spindle, but if the swingarm is even slightly tweaked of the frame is even slightly out, then it will not put the wheels in line.

Brand new bikes out of the crate have wheels up to 3mm out of line. Most of that is adjustment, but it's compounded by manufacturing tolerances, wear and tear etc.

The technique I use is slightly more expensive but very simple. Get two 8 foot long pieces of 1" square aluminum and make sure they are dead straight. Place one each side of the rear wheel about 6 inches up from the ground. Then check the gap at the front and rear edges of the front wheel on both sides. The gap should be the same back and front left and right.

If you don't have an assistant to hold them at the rear wheel while you check the front, use a couple of bungee cords and rest the straight edges on a small box or brick to hold them more or less level.

Re: Dumb Question... Adjusting chain.

Posted: Sat Oct 30, 2010 9:01 am
by H2RICK
I've always aligned my SPROCKETS, rather than my wheels. That keeps the chain running correctly with zero side plate rubbing on the sprocket teeth and the actual thrust from/to the sprockets is thus on the centre of the rollers where it's supposed to be.
Wheel alignment is a whole 'nother subject, IMO.......
However, unlike many folks, I (fortunately) have the advantage of knowing that my bikes haven't been abused so the frames/swingarms aren't twisted and the swingarm bushings/bearings are in good condition. This allows me to be confident that if the sprockets are aligned properly then the wheels will track properly.

Re: Dumb Question... Adjusting chain.

Posted: Sat Oct 30, 2010 9:08 am
by crash277
my street bikes are not abused, but my race bike is another story. its done some acrobatics. :wth:

there are chain alignment lazers and apparently they work awesome, but i think a decient tape measure and a straight edge work for me until i win the lottory lol

Re: Dumb Question... Adjusting chain.

Posted: Sat Oct 30, 2010 9:13 pm
by Coyote
My method is a bit --- well a lot more crude, but it has worked well for me over the years. I pretty much go by feel with my fingers between the tire and the swigarm in the forward part (the part you can't really see). When my fingers say they are about equal, then I sight down the sprockets as per H2Rick and tweek as necessary.
Sometimes it's tricky to get all things to happen all together with the chain at the right tension. Many many times I have wished the adjusters were pullers and not pushers. It all seems assed backward to me.
Final test is to run her down the road and take your hands off the bars. It should track straight, be easy to balance and not veer to either side. Veers to the right then point the wheel a little more to the right and vice verse.