Chain Adjustment

[Angus]

I notice my chain has about 7 centimeters of play. I have read that 2 1/2 is the recommended amount of play. Therefore I'm wondering if it is an easy enough job to tighten the chain. I'm most concerned about getting the wheels in alignment after I have done the tightening. Apparently I have to measure from the axle to the drive sprocket to make sure they are exactly the same and that means that the wheels are in alignment? Also is it really necessary to use a torque spanner as I don't have one? Is this a straightforward enough job for an amateur? I don't want to have to worry as I'm going up the road that the chain is going to snap or come off.

[Mr Nick]

70mm of play is a lot: you really need to get that sorted.
Since you only have a front sprocket on one side, measuring to there isn't really going to work. If you just slacken the axle and make small adjustments equally, then it should still be in roughly the same alignment it was before you started. However, you can buy a chain alignment tool for under £10 that makes the job easier: it screws on to the rear sprocket & a rod points where that's aligned to, which you aim at the front one.   
A torque wrench isn't critical, if you have a good feel for the torque you're applying. I'm going to hazard a guess that this isn't where you are yet so I'd suggest getting one to make sure you are in the right ballpark. £20 or so isn't a high price for peace of mind.

[Joe Rocket]

I use a small metal ruler marked in O.5mms and place it against the rectangular 'washer' on the axle and measure back to the adjuster. As Mr Nick says make small equal adjustments alternately to each adjuster bolt and get back to 20 to 30mm at the tightest point in the full chain rotation.

It is noted to do it on sidestand because the bike isn't sold with centrestand from new unless you have one put on. There is no big difference adjusting the chain on side or centre stand, if you set it at 25mm you'll be fine.

[mrp192]

I worry about chain tension on my 2015/Glee and measure the free play before every ride. I’ve had a Scottoiler fitted from new and now approaching 40k Miles am only in my second set of C&S.
I find the only time I need to adjust it is when it comes back from service and been adjusted too tight (nearer 20, than 30 mm). On recommendation on here I always run it nearer the 30 mm as it makes for a much smoother gear change.
To help with alignment, I use the swing arm markings but then put a small led torch on the top run, just in front of the sprocket cover, and then look along the chain run from the rear. It is really obvious when the wheel is even only slightly out of line.
As for side stand/ main stand I find on the side stand it shows slightly tighter for some reason. So after getting it set and torqued up I check it on the side stand, rolling forward several times , and then mark the tightest spot.
On my pre-ride checks I do it on the main stand, measuring at the rear of the plastic rubbing guard which is just about halfway between the two sprockets, and look for it to be just under 30mm at all points I check, starting at the tight spot.
As for torquing the wheel nut, I do every time. It’s a small investment for peace of mind but bear in mind to wind the setting back to zero after each use.
I hope I’m not ‘teaching you to suck eggs’, I’m only a hobby mechanic and you will hear from lots of very capable mechanics on here.

[UK_Vstrom650]

Only to add, don't torque it to the spec in the manual as I recall Greywolf saying the figure was wrong & you should use between 80nm and 100nm depending if you use grease on the threads or not.
(https://www.stromtrooper.com/threads/rear-axle-thread-galled.23698/#post-228689)

[Ian P]

Hi Angus,

I have always found that too loose is far better than too tight.
70mm is a bit too loose, and 25mm I think is a bit too tight. You run more risk of breaking the chain or running the gearbox countershaft bearing and seal if too tight.

on my 2008 wee I run the chain at 35 - 40 mm of slack usually measured with slight finger pressure pulling and pushing the chain up and down at the mid point of the run in several places as I rotate the wheel.
Some people even recommend 50 mm and I can understand this if venturing off road where the suspension will get more of a workout.

I have checked it this way on the side stand and the centre stand and have not noticed a big difference, certainly not worth worrying about.

As to the chain alignment I just use the marks on the swingarm, many people will claim that they are not accurate but I disagree. This method has served me well enough over the last 50 years of riding and well over 70 bikes.

For your question about the axle nut torque I would beware tightening to the figure given in the manual as this has proven to be too tight and can cause the threads to gall. This can cause them to strip when next you undo it.

The last time I changed the chain and sprockets I just tightened the axle nut by feel using a long ring spanner and judicious application of foot.

Regards.
Ian

[Joe Rocket]

We've come from clip joints in chains and boiling them in wax to being super cautious over changing chains and sprockets, even oiling them after every ride. Riding habits also have a bearing on longevity and probably abuse will break things sooner.

Saying chains 'could' break or final drive shaft (what's a counter shaft?) bearings and seals 'fail' need some proof or statistics to show a probability or likelihood. Personally I've never seen either but there must be some instances somewhere. Stripping an axle thread too. 

Like changing engine oil good maintenance will serve the bike well and regular checking of chain tension is fine going by the Owners or Service manual.

I've not seen any standard for tightening bolts on an undetermined length of spanner nor the foot method. I use a torque wrench because it takes the guesswork out of the equation.

I've no complaint with your methods Ian P, what you do with your bike(s) is up to you, of course.

[Ian P]

An ex girlfriend broke a chain on her Z750 after her dad decided that the chain was too slack and did it up to the point that there was not slack at all.
I asked him afterwards why he did this and he said that's how he had always done his bikes, note he had only ever had one, a Yamaha 125 that was apparently so fast that his son wasn't allowed to ride it, and his only other experience was riding his brothers Norton navigator, again another really fast bike 

I have also see them break in MX racing after being set too tight. One incident was after the bike had been scrutineered and picked up for a too tight chain. But the owner ignored this, and its only an advisory. He was lucky his kid didn't get the chain whip his leg when it broke.

As I understand it a countershaft is a gearbox output shaft, the mainshaft is the input shaft.

Also if you over tighten a thread they can gall or pick up which is the thread surface starting to break up. Then when you undo the thread starts to break away. I have seen this happen many times, usually at the hand of ham fisted mechanics.

This is more problematic when using stainless fasteners into soft alloy cases and I always use copperslip grease in that case.

regards.
Ian

[Angus]

Thank you. How important is the torque precision on the rear nut? If I just tighten it up fairly tight would this be OK? Don't feel like spending 90 quid on a torque spanner I'd probably use once a year. But I guess if necessary I will do so.

[Brockett]

A torque wrench also controls the spanner monkey inside me from over tightening a fixing stripping threads and breaking parts.
Some fixings should be tightened to the required torque value to ensure they stay in place. I do not know if that is down to thread shape or metallurgy of the fixing but when I look at a wheel axle I rarely see a spring or lock washer and that, I believe is because the force acting on the fixing is such that the thread acts like a spring washer. By not applying sufficient torque the fixing may come loose.
But what do I know? don't answer .... it'll take too long.

[Ianmc]

   Where do you get £90 from, if you are only an occasional user just go on ebay and get one delivered to your door for £17.67p.It even comes with a calibration certificate.Better still the seller is in the UK.
   

[Mr Nick]

The question that you need to ask is how important is the part that the nut holds on? Would it be OK if it came loose whilst you were out on a ride? That will inform how important getting it properly fastened is.

[Savak]

You could buy one of these to get the rear wheel off the ground.

[Rusty Nuts]

As an aside, why are there no castellated nuts with split pins/ R clips, or tab washers on wheel spindles?

[Ianmc]

     Because nyloc nuts are probably cheaper, plus they are supposed to be a single use only item.Therefore more money in dealers tills.


       Angus,Aldi have got torque wrenches in their stores this week,and they are cheap, but good enough for the occasional user who does not need them to be checked for calibration every few weeks or so.

[Joe Rocket]

Ianmc, you raise a couple of interesting points there. I'm not aware that the axle nut is nyloc. I'm not sure where single use is of any advantage to regular maintenance as the chain should be checked every 600 miles and adjusted if necssary, slackening and retightening the bolt. Neither my handbook nor manual refers to it having to be replaced (ever?). Castellated nuts and split pins are mentioned where fitted. I have an R clip on my GPX nut but I do think it isn't permanent enough; ie: can be easily stolen.

Also wouldn't a nyloc nut change the required torque setting not knowing the resistance of the extra locking of the nut?

 

[Oop North John]

Nyloc nuts - Where they're used in critical locations then usually there's a run down torque minimum for their continued use. But it's dependent on who's regulations etc you're operating under: https://en.wikipedia.org/wiki/Nyloc_nut

[Ianmc]

   I have just been out to the garage and had a look at the rear axle nut on my bike, although it looks just the same as a Nyloc at first glance, it is actually an all metal locknut of a type I have never seen before.It has as far as I can make out 4 pieces of thin shim steel pieces set into the area of the nut that the nylon locking ring would be.More usually an all steel locknut is used in a high temperature location,and they have a”crimped” end section or a “split” section that has the threads slightly distorted.So I reckon it could be used on a fairly regular basis without needing to be changed.
      When a Nyloc nut is used on an item that is required to be “torqued”,the extra friction is calculated into the final torque setting.
    Talking about split pins through a nut as a locking device, in the sixties, some Leyland trucks used to have big end bolts that were not torqued up, they used to measure the stretch in the bolt when tightening initially, and then drill though the big end bolt to fit the splitpin through a castellated nut, and then centre punch mark the nut to suit.So you had to keep every big end nut with its mating bolt.When reassembling you tightened the nut until the marks lined up with the hole in the bolt.

[Joe Rocket]

Thanks Ianmc. I was tempted to go out and look at mine tonight but it's too dark. I shall have a look tomorrow.

The difference I now see is that the torque requirement has the 'performance' of nut included. I thought it was simply a setting that would not come undone as there is no locking device (but the nut is reliable enough as said locking device). Reference to split pins is simply the earlier mechanical requirement with castellated nut, where fitted.

 

[Gert]

A touch of grease / lube on axle thread, followed by a slightly reduced torque on the axle nut.
A suggestion to do a search, on this site, for "axle galling"
Search results for: axle galling, lists 10 hits on the subject.