Author Topic: chain tension - allen key size (Read 5059 times)

dxtans · « **on:** August 18, 2013, 17:34:38 »

Hello,
I seem to have misplaced my allen key to adjust the chain. Need to get a new one.
Does anybody know the size of the allen key I need to purchase

Thanks
DT

Juvecu · « **Reply #1 on:** August 18, 2013, 20:58:09 »

Pretty sure it's a 6mm one, but I went looking for my chain adjusters and couldn't find them (bike is in bits and I have no idea what I did with them

) Best wait for someone else to check for you.

Mr Nick · « **Reply #2 on:** August 18, 2013, 22:27:03 »

5mm on the Glee.

greywolf · « **Reply #3 on:** August 18, 2013, 22:40:19 »

It is 5mm for Wee and Glee.

Juvecu · « **Reply #4 on:** August 18, 2013, 23:22:15 »

I was only 1mm out

greywolf · « **Reply #5 on:** August 19, 2013, 00:28:45 »

I was thinking it was probably 6mm too before I went out and measured it.

dxtans · « **Reply #6 on:** August 20, 2013, 09:26:27 »

Hello,

that's great, thanks, now got a new one.
However looking at one of the bolts on the chain tensioner , it looks like I will have to replace one of the (allen) bolts, not turning to well, no grip. Can these be ordered sperately or do I have to purchase the who tension kit bit. Do these bolts actually unscrew completely, then come out, ( I have not tried this yet,)

Thanks
dxtans

frez · « **Reply #7 on:** August 20, 2013, 09:48:28 »

If you are using an allen key (I.e. bent bit of hex metal) you will often struggle with getting enough leverage on some of the allen fasteners and may well round them off. A much better plan if you have a socket set is to buy some allen sockets, you can then get a breaker bar on there if you need to. Here's a cheap set that will do the job; http://www.screwfix.com/search.do?fh_se ... eFilterOn=

Jacko · « **Reply #8 on:** August 20, 2013, 10:39:29 »

You shouldn't need to put any pressure on these, they nip up once the axle is tight, and they're loose when you undo the axle. If you're ever putting enough torque through them to round them off you're doing something wrong.

dxtans · « **Reply #9 on:** August 20, 2013, 11:17:54 »

It had a lot of crap on the bolt( on the inside) , initially wouldn't move, so that's where the rounding off came about, trying to turn it. So sprayed some penetration spray, on it /inside left it for a day and now all is OK, it turns.
But concerned about the rounding off of the bolt hole. Would prefer to put a new/replacement one in.

So does anybody know the size of these bolts, maybe get one from B&Q,

Thanks
dxtans

Juvecu · « **Reply #10 on:** August 20, 2013, 20:46:35 »

You have the Allen key, you can take the good one out and measure it

I'm pretty sure they are M8 Allen dome colts, but I have no idea how long they are. You could replace them with some A2 or A4 stainless ones.

dxtans · « **Reply #11 on:** August 21, 2013, 06:26:24 »

You're right, and that's what I am going to do this week-end, I'll pop up to B&Q, with the bolt in hand and hopefully find a replacement.

Thanks
dxtans

Juvecu · « **Reply #12 on:** August 21, 2013, 10:38:01 »

I'd measure them for you if I could find my chain adjusters, bit worried now that I don't know where they are. Just easier for me to do it because they aren't on the bike at the moment. If I remember I'll have another go at finding them when I get home this afternoon, I'll be in the garage anyway.

dxtans · « **Reply #13 on:** August 21, 2013, 19:10:51 »

No worries, I've taken one out , got a pair od hex nuts from halfords. Banged the rear spindle out , and gave it a wire brush clean and some copper grease treatment. The bolts fit a treat !

Thanks for everybodies help and advice.

I think my next purchase is going to be a torque wrench, to correctly tighten the rear spindle after a chain adjustment. I think this is where my troubles all began.

Thanks
dxtans

greywolf · « **Reply #14 on:** August 21, 2013, 20:34:50 »

Copper grease is good for the axle nut too. When using it though, only use about 80% of the specified dry torque to account for the lubrication.

Tusker · « **Reply #15 on:** August 21, 2013, 20:39:57 »

you have lossened the axle nut have'nt you

Mine turn very easilyn aftern that....

dxtans · « **Reply #16 on:** August 22, 2013, 06:49:17 »

Yes, but since I've had the bike I may/have have over tightened the spindle nut on many occasions , after finishing the chain tension. I think this may have caused the issues I had...I think in the long run. ( I know it does not do the rear bearing any good, from an over tight nut). That's why I'm going to use a torque wrench next time I do the spindle/rear axle nut up. Just purchased one of Amazon for £30, cheap and cheerful, but should do the job.

dxtans

frez · « **Reply #17 on:** August 22, 2013, 09:28:03 »

When you loosen off the axle I find giving it a little tap on that side a good plan too as the other side of the axle can still be tight up against the swinging arm and make adjustment that side more difficult, so by giving a little tap you knock the axle through a little bit and loosen the other side.

iansoady · « **Reply #18 on:** August 22, 2013, 12:31:26 »

Quote from: "dxtans"

( I know it does not do the rear bearing any good, from an over tight nut).

dxtans

It shouldn't actually cause the bearings any problems as you're just tightening up on the inner races / spacers. Not like steering head bearings where overtightening does cause problems.

If you overtighten something like the spindle you can cause the threads to stretch so it won't tighten properly in future.

greywolf · « **Reply #19 on:** August 22, 2013, 17:01:49 »

The biggest problem is galling. There have been many reports of the nut cold pressure "welding" itself to the axle/spindle. Copper grease or another anti-seize product containing a metal in grease formula will prevent that. I use molybdenum based anti seize from a tube I've had for over 30 years. Again, only use 80% of the spec to account for lubrication. In this case, use 80Nm instead of 100Nm when adding anti seize.