Replacing parts before they fail

[Yellow Saddle]

Did use. It was then subsequently edited. Surprised you are going for the ad hominems, when you've had so many yourself, according to your post history. What was that word I used earlier?

I intended no malice and certainly no ad hominem. I just could not figure out whether the use of "faded" was intentional or one of them auto-correct errors. Credit where credit is due. Faded is now part of my cable lexicon. I like it. Still don't like "snap" or "forks".

 

[I like Skol]

Cables tend to go a bit stiff or slow, by that i mean gears change poorly on the way down the block.
i renew the inners as soon as that starts..and occasionally the outer if its still a bit naff after threading a new inner...

Not to get all YS about it but this is the wrong way to go! If you have a good quality stainless steel inner (I like genuine Shimano inners and outers) and shifting is sluggish then simply changing the inner is unlikely to change much (unless you introduce some additional lube to the system at the same time which you could have done anyway without the expense of fitting a new inner cable). The 1st port of call would be some lubricant, then outers providing the inner is good with no corrosion, fraying or kinks, then finally the full suite, inners and outers.
My hybrid is approaching 15k and has had the rear inner replaced once because shifting was getting a bit suspect and when I replaced the outer I used slightly longer outers to get a better cable line so consequentially needed new inner cable for the additional length.
Replacing working parts with no indication of wear, simply as a precaution is a mugs game and unforgivably wasteful.

 

[Deleted member 35268]

I've replaced everything except my actual bike frame. Some parts don't give much warning of failure, but some do. It's up to you if you want to ignore the signs, but sometimes you have to just get on it and ride on.

 

[Globalti]

Careful inspection is the key; I inspect my tyres regularly as they are quite important at 45 mph! GtiJ didn't and was astonished when his latex inner tube herniated though a hole in the tyre and burst with a spectacular flatulent squeak. While we fitted a butyl inner beside the road he admitted that after the last ride he had noticed the pale green latex inner showing inside the small hole!

 

[mjr]

All this can be prevented by greasing the taper before fitting the crank and torqueing it to the correct setting first time. A greased taper settles into its preferred position immediately upon installation rather than gradually. An ultra-small amount of grease is all that's necessary, even just greasy fingers handling the BB is enough to make it fit perfectly.

The grease aspect of the above advice is actually quite controversial, mainly because most modern greases contain stuff which is accused of interfering with formation of the taper-crank joint.

The torque bit probably isn't. For most square-taper axles, it'll be in the region of 40 N m and beyond the range of many cycling torque wrenches. You can use a garage torque wrench but you may need a special thin socket to fit in the crank - the "other" end of some square-taper crank pullers is such a socket and removing the puller end (dark in the pic below) presents a 16mm (I think) nut that you can get a spark-plug socket over.

Or you can use a 1/2" to 3/8" drive adapter (about £2 from DIY barns) and then I think many 3/8" drive 14mm sockets will fit in.

Going back to the original stuff: for rides of less than 50 miles from home, I tend to deal with failures when they happen. When the rear gear cable snapped, I used the limit screws to pick a gear good enough to get home. For longer trips, I carry a spare cable or for bigger things, find a shop.

 

[Ajax Bay]

Surprised you are going for the ad hominems

You really can't call that polite even complimentary reference to 'fading' v 'failing' "ad hominem"; at least not without postscripting a , as you did when calling YS a(n old) "hypocrite".

 

[S-Express]

You really can't call that polite even complimentary reference to 'fading' v 'failing' "ad hominem"; at least not without postscripting a , as you did when calling YS a(n old) "hypocrite".

The ad hominem reference was in relation to his previous post #11.

 

[Ajax Bay]

The ad hominem reference was in relation to his previous post #11.

 

[Yellow Saddle]

The grease aspect of the above advice is actually quite controversial, mainly because most modern greases contain stuff which is accused of interfering with formation of the taper-crank joint.

Do you have any more info on this for me?

The torque bit probably isn't. For most square-taper axles, it'll be in the region of 40 N m and beyond the range of many cycling torque wrenches. You can use a garage torque wrench but you may need a special thin socket to fit in the crank - the "other" end of some square-taper crank pullers is such a socket and removing the puller end (dark in the pic below) presents a 16mm (I think) nut that you can get a spark-plug socket over.

A good bike should have a torque wrench with 40NM in its midspan range. And as you say, 1/2 inch sockets are usually too thick to fit in the crank. I used to just turn down the ends of my Gedore sockets but then later one someone pointed out that Stahlwille sockets fit perfectly. For that one - 14mm - the price can be overlooked.

 

[mjr]

Do you have any more info on this for me?

Most recently http://forum.cyclinguk.org/viewtopic.php?p=1047528#p1047528 but it's not the first time I've read similar things.

A good bike should have a torque wrench with 40NM in its midspan range.

Possibly but lots of bike torque wrenches don't. My Topeak Torq tops out at 12Nm, the Park TW5 at 15Nm, the Lifeline (recently discussed on this site) at 24Nm. The Park TW2 does have 40 squarely in the mid-range, though.

And as you say, 1/2 inch sockets are usually too thick to fit in the crank. I used to just turn down the ends of my Gedore sockets but then later one someone pointed out that Stahlwille sockets fit perfectly. For that one - 14mm - the price can be overlooked.

A smidge over £10. Yes, that's pretty high.

 

[Yellow Saddle]

Most recently http://forum.cyclinguk.org/viewtopic.php?p=1047528#p1047528 but it's not the first time I've read similar things.

Thanks. I quickly read through that and I disagree with several aspects. The author seems to think that cold welding occurs in crank interfaces. I don't. He/she seems to think that some greases may not work but doesn't say why other than that they may contain things not stated on the label. I disagree.
He/she doesn't seem to understand that crank tapers have a leading edge and trailing edge which are increasing/decreasing compression when cycling and how this affects crank creep. I still don't see what ingredient in grease can prevent proper fit.

[/QUOTE]
Possibly but lots of bike torque wrenches don't. My Topeak Torq tops out at 12Nm, the Park TW5 at 15Nm, the Lifeline (recently discussed on this site) at 24Nm. The Park TW2 does have 40 squarely in the mid-range, though.
[/QUOTE]
Yes, bike shops push the small, low-range 1/4 inch wrenches for protecting expensive parts and thin bolts in the 2-16NM range.

 

[jefmcg]

used the limit screws

Limit screws! Doh!

 

[mjr]

Limit screws! Doh!

Actually, you only have to use the H limit, because with no cable, most rear derailleurs will sit at the highest possible gear. They "fail high".

Just one of my many bodges learnt in my bike-bending youth, although I last used it a year or so ago. One reason I like rear racks on a bike is that I can pick up bits that fall off and get them home!

 

[jefmcg]

I knew that bodge, but I'd forgotten it. Though to honest, getting it properly sorted while I browsed round a shop was the best outcome. However, I would have been ok with the right two gears.

It's happened to me once before on the loneliest part of LEL. Other riders got helped me, and must have done that, but I had forgotten. The mechanic who sorted it out for me had only ever worked on friction shifters before

 

[Dogtrousers]

The hi limit screw, IME, won't get you far enough in for a decent compromise. One gear, maybe two. When this happened to me a few years ago I used the limit screw and struggled home on a rather high geared two speed. Fortunately it was a flat ride.

But I've read of a really cunning way: Take the cable out, seat the nipple in the cable stop on the frame and feed the remaining cable into the mech. This should enable you to shove the derailleur to a mid-cassette position and tighten down the cable grip screw thingy. And also have a load of extra cable hanging out the back of your mech which you will have to coil up. There may even be a fine tuning barrel adjuster there to twiddle to get it perfect. (I've never actually done this, just read about it).