The friendly "dumb" bike questions thread

[KTMsm]

Prof Prolapse said:

I'd really be curious to learn the rationale of anyone using copper grease. As above, I'd not use any grease unless it's indicated, but copper grease melts at about 100degC, eats rubber, attracts debris, and looks bloody terrible.

It's absolutely just the wrong tool for the job as far as I can tell.

I haven't used it on my bikes

I have on cars - mostly for the old pads which were bare metal, most of the modern ones have a backing designed to do the same thing

[Krikkit]

KTMsm said:

Krikkit said:

I'd never use copper slip on brakes, I'd think about using it in setups with sliders which are sealed from the weather (i.e. a car),

NOOO !

Copper slip is the worst thing for sliders it gums them up, it they have the rubber bush use rubber grease, if they don't I use high temp lithium

I have them out and clean once a year so it doesn't generally get time to gum up. I tend to use lithium stuff if I have it, but otherwise copper slip or plain old moly seems to do fine.

[Prof Prolapse]

Copper grease is an anti-seize compound, not a lubricating grease. So in addition to the issues I said before it's actually not helping anything?

My understanding is that Lithium grease is actually a lubricating grease, so that's better. It also has a higher melting temp ~100-200degC, but I would think temperatures will still exceed this in routine use. It's also still petroleum based, so it will also rot any rubbers.

[Krikkit]

It's just standard moly with copper particulates suspended in it, so it does absolutely fine in a pinch.

Irrelevant as none of it actually goes near a set of bike brakes, which are just clean and dry.

[KTMsm]

anonymous said:

[redacted]

As long as it hasn't been topped up with low pads it'll be fine, just keep an eye on it

I would mention that the cheapest way to improve your brakes is a fluid change IME as hardly anyone ever does, so it's probably as old as the bike !

[Deranged Granny]

Prof Prolapse said:

I'd really be curious to learn the rationale of anyone using copper grease. As above, I'd not use any grease unless it's indicated, but copper grease melts at about 100degC, eats rubber, attracts debris, and looks bloody terrible.

It's absolutely just the wrong tool for the job as far as I can tell.

I've always been taught to use a very thin smear of copper slip on the back of pads to prevent squealing. I've never had any squealing so have no reason to believe it doesn't work. The copper slip shouldn't go near any rubber, it just allows there to be some slip between the piston and pad so the pad doesn't vibrate and squeal. I use a half pea sized amount as I don't fancy lubricating my pads and discs. So the copper slip shouldn't go anywhere other than the back of the pad.

Red/rubber grease I use when rebuilding calipers, smearing them on the seals to keep the rubber supple.

Edited by Deranged Granny on Wednesday 5th May 09:08

[Prof Prolapse]

Deranged Granny said:

I've always been taught to use a very thin smear of copper slip on the back of pads to prevent squealing. I've never had any squealing so have no reason to believe it doesn't work. The copper slip shouldn't go near any rubber, it just allows there to be some slip between the piston and pad so the pad doesn't vibrate and squeal. I use a half pea sized amount as I don't fancy lubricating my pads and discs. So the copper slip shouldn't go anywhere other than the back of the pad.

Red/rubber grease I use when rebuilding calipers, smearing them on the seals to keep the rubber supple.

Edited by Deranged Granny on Wednesday 5th May 09:08

I'll make this my last post about it as I'm boring myself... It's definitely what they used to say in "the old days" (before Caliper grease) for sure, they even show pictures of calipers on some copper grease tubs, but as I understand it, it doesn't seem to stack up with the physical properties of the materials, and I'm siding with those.

And no disrespect meant, but what you've just said is specious reasoning. I don't know if you remember the Simpsons reference where Lisa tells Homer she has a rock that keeps tigers away, she says it doesn't work, but "do you see any Tigers?", at that point Homer buys the rock from her.

It's not a big deal of course, probably not worthy of this level of discussion. I just think it causes increased work and wear, with no benefit.

[Deranged Granny]

Prof Prolapse said:

Deranged Granny said:

I've always been taught to use a very thin smear of copper slip on the back of pads to prevent squealing. I've never had any squealing so have no reason to believe it doesn't work. The copper slip shouldn't go near any rubber, it just allows there to be some slip between the piston and pad so the pad doesn't vibrate and squeal. I use a half pea sized amount as I don't fancy lubricating my pads and discs. So the copper slip shouldn't go anywhere other than the back of the pad.

Red/rubber grease I use when rebuilding calipers, smearing them on the seals to keep the rubber supple.

Edited by Deranged Granny on Wednesday 5th May 09:08

I'll make this my last post about it as I'm boring myself... It's definitely what they used to say in "the old days" (before Caliper grease) for sure, they even show pictures of calipers on some copper grease tubs, but as I understand it, it doesn't seem to stack up with the physical properties of the materials, and I'm siding with those.

And no disrespect meant, but what you've just said is specious reasoning. I don't know if you remember the Simpsons reference where Lisa tells Homer she has a rock that keeps tigers away, she says it doesn't work, but "do you see any Tigers?", at that point Homer buys the rock from her.

It's not a big deal of course, probably not worthy of this level of discussion. I just think it causes increased work and wear, with no benefit.

Haha, of course I was aware of the lack of causative proof. But I'm not going to do a chemical analysis every time I need to use a bike product. I trust that more experienced people than I have a better idea of what to use; you would expect that prevailing wisdom is based on fact somewhere down the line.

In the meantime - do you know where I can buy one of those rocks?

[Steve Bass]

Prof Prolapse said:

Deranged Granny said:

I've always been taught to use a very thin smear of copper slip on the back of pads to prevent squealing. I've never had any squealing so have no reason to believe it doesn't work. The copper slip shouldn't go near any rubber, it just allows there to be some slip between the piston and pad so the pad doesn't vibrate and squeal. I use a half pea sized amount as I don't fancy lubricating my pads and discs. So the copper slip shouldn't go anywhere other than the back of the pad.

Red/rubber grease I use when rebuilding calipers, smearing them on the seals to keep the rubber supple.

Edited by Deranged Granny on Wednesday 5th May 09:08

I'll make this my last post about it as I'm boring myself... It's definitely what they used to say in "the old days" (before Caliper grease) for sure, they even show pictures of calipers on some copper grease tubs, but as I understand it, it doesn't seem to stack up with the physical properties of the materials, and I'm siding with those.

And no disrespect meant, but what you've just said is specious reasoning. I don't know if you remember the Simpsons reference where Lisa tells Homer she has a rock that keeps tigers away, she says it doesn't work, but "do you see any Tigers?", at that point Homer buys the rock from her.

It's not a big deal of course, probably not worthy of this level of discussion. I just think it causes increased work and wear, with no benefit.

Back in the day, it was widely recommended to put a light smear of CopperSlip onto the back of pads to help eliminate squeaking or squeal.
But these days, with improved shim technique and manufacturing, if anything, a light non mineral grease is acceptable. Delphi now recommends no copperslip be used at all.
It's a case of age related experience....

[Deranged Granny]

Lesson learned; don't give out mechanical advice

[Krikkit]

Deranged Granny said:

Haha, of course I was aware of the lack of causative proof. But I'm not going to do a chemical analysis every time I need to use a bike product. I trust that more experienced people than I have a better idea of what to use; you would expect that prevailing wisdom is based on fact somewhere down the line.

Problem is this kind of wisdom isn't updated by the experienced people - it's a well known effect that the more experience people have the less likely they are to adopt and update their techniques based on up-to-date info.

Ultimately it probably makes no difference at all in the real world, so carry on

[Steve Bass]

Deranged Granny said:

In the meantime - do you know where I can buy one of those rocks?

Drop me a line, I have a field full of them.. absolutely no tigers by us, leopards yes, tigers.... no..

Edited by Steve Bass on Wednesday 5th May 10:28

[Zarco]

I think I know the answer to this.



Does this chart mean a Large Shell Size NXR is the same fit as a XL Shell Size X-Spirit 3? As this might explain why my new helmet is too tight!

[airsafari87]

Zarco said:

I think I know the answer to this.



Does this chart mean a Large Shell Size NXR is the same fit as a XL Shell Size X-Spirit 3? As this might explain why my new helmet is too tight!

I've just replaced my large NXR with thicker 39mm cheekpads as it was a bit small for me since losing weight, for a medium X-Spirit 3 with std 35mm cheek pads and it fits perfectly.

[Zarco]

airsafari87 said:

Zarco said:

I think I know the answer to this.



Does this chart mean a Large Shell Size NXR is the same fit as a XL Shell Size X-Spirit 3? As this might explain why my new helmet is too tight!

I've just replaced my large NXR with thicker 39mm cheekpads as it was a bit small for me since losing weight, for a medium X-Spirit 3 with std 35mm cheek pads and it fits perfectly.

Do you mean the NXR was a bit big? Otherwise I'm confused.

My L NXR fits well. Obviously worn in. New L X-Spirit 3 feels head ache inducing, and the chin pads are much tighter but feel good.

[Krikkit]

Zarco said:

Does this chart mean a Large Shell Size NXR is the same fit as a XL Shell Size X-Spirit 3? As this might explain why my new helmet is too tight!

I don't think so, I think it just means they do more sizes of one than the other.

[airsafari87]

Zarco said:

Do you mean the NXR was a bit big? Otherwise I'm confused.

My L NXR fits well. Obviously worn in. New L X-Spirit 3 feels head ache inducing, and the chin pads are much tighter but feel good.

Sorry, yeah I meant the NXR was a bit big, but only a touch too big.

[talksthetorque]

Another Helmet question.
My helmet feels as if it fits fine - but when I get over 70 an up to (and occasionally past) 100 it seems to push back more against my face and I find myself riding along with my mouth open to stop it moving about.
I get the physics of the wind hitting it is pushing it back but do you guys (and girls if there are any) have to do this?
When buying 18 months ago, one size down pressed in the centre of my forehead so I went for this size which as I said feels fine the rest of the time.

Speeds quoted in km/h of course

[GriffoDP]

I don't get this. If it's squishing the sides of your face-head enough then it should be mostly static. In my opinion. Perhaps you need thicker side cushions, if your lid has such.

My first ever lid I got in L as I was scared of it getting stuck on my head! A year or so later as I went to replace it after a low off, I found that M was better, and some speed-wobble of the L lid I used to get was then gone!

Edit: I should say, I think on nakeds I can feel it pushing slightly, but not enough to ever have to adjust anything or open mouth.

[trickywoo]

talksthetorque said:

Another Helmet question.
My helmet feels as if it fits fine - but when I get over 70 an up to (and occasionally past) 100 it seems to push back more against my face and I find myself riding along with my mouth open to stop it moving about.
I get the physics of the wind hitting it is pushing it back but do you guys (and girls if there are any) have to do this?
When buying 18 months ago, one size down pressed in the centre of my forehead so I went for this size which as I said feels fine the rest of the time.

Speeds quoted in km/h of course

A helmet shouldn’t move on your head at all. Sounds too big to me.

A mistake a lot of people make is to get one that doesn’t squash your cheeks at all. It should be difficult to do a chewing motion. If you’ve got a skinny face less so but the principle is the same.

If you get a helmet that doesn’t pinch at all when new it will be too big once the padding has seen some wear.