Betenoire

Hi, I recently took apart the 5-speed gear hub from a bicycle that had been sitting in storage for 10+ years. I used liberal amounts of WD40 on the inner parts to wash out all the dried up grease that had more or less turned into glue. Would that have been some sort of synthetic lubrication?

Next step of course is to apply substitute grease so this bike can go back on the streets. With no actual signs of wear at this point, it should still have many years of daily use ahead of it. I'm using just a cheap oil based "bearing grease" for almost everything else, but I was thinking, should I perhaps use something else for this occasion? Of course, gear hub manufacturers will try to sell their own special lubrication products. But there are also generic brands that have added teflon, graphite, or whatever.

So, which one of those would be best? Or would my regular cheap grease be "good enough", after all?

Thank you for any insights.

riverrider

google "sheldon brown" and search for the Shimano Nexus Hub. There is lots of advice on how to lube an internal geared hub. One particular part I remember is that most damage is done to the internal gears when the wrong lube is used. Be careful...be very very careful.

jgedwa

Acc to SB, the most common reason for Nexus hubs failing is the use of wrong grease. Shimano sells their own stuff for these. Maybe there is some generic substiture, but I do not know what it is. Maybe someone here will know. I, for one, would be reluctant to use a substute in it.

jim

Betenoire

Thank you both. Yes, I do plan to be careful, that's why I thought to ask here first

Believe it or not but I had already seen Sheldon's page about the Shimano Nexus. But (a) my hub is not a Nexus but an older Sachs Pentasport and (b) I'm still somewhat sceptical of the idea that you can only use *one* brand of grease inside such a hub. Oh and (c) I admire Sheldon Brown enormously but I try to not always take everything he says as gospel only because he says it.

Perhaps I should rephrase the question: if one would have to regrease a gear hub without the brand specific grease, what grease would be acceptable as a substitute?

Or, in even other words: what is so freaking special about the brand specific greases to begin with?

jgedwa

I would not take anyone's word as gospel. But one could do worse than to begin bike questions with Mr. Brown.

I too am inclined to think that the brand is of no consequence. But what might be of supreme consequence would be the weight and viscosity of the grease. There is a tremendous amount of variation in greases, from the almost-oil of Phil's Tenacious Oil, to the thick greases of auto bearing grease. Go too thick and maybe it will not splash around and lube where it needs to lube, go too thin and it might run out of the places it is meant to stick and lube.

But, unfortunately, I do not have an answer to your question. I know old SA hubs took thin oil, and I know newer Nexus hubs take a fairly thick grease. Other than that, I know nothing.

jim

Betenoire

Quite right! And I would not normally go against Mr. Brown but I think that even he would agree there is often more than one way to do something.

In fact, I think Sheldon Brown is something of a bicycle hacker, which in my mind is a good thing, and he has probably not always taken as gospel the instructions from manufacturers himself.

I know I can't use a thin oil in this one because it is a combined gear hub and hub brake (not a coaster brake). The two parts are reasonably well separated in the middle but of course not 100% and a thin oil if it ever crept into the brake compartment could easily cause trouble there. So it must certainly be something thicker than that. Perhaps my cheap regular grease, which is a lithium grease, after all. I will try to use a grease gun with a fine needle to get the stuff into the right places and ask the owner (a family member) to return to me with it after a few weeks.

Thanks for your thoughts.

Sheldon Brown

Actually, that remark was specifically relating to Shimano Nexus 7- and 8-speed hubs. There seems to be some mechanism inside these hubs that is very picky about viscosity.

I believe that SRAM/Sachs hubs are much less fussy about this. I would use grease in the bearing races but oil for the rest of the mechanism. Partly it will depend on temperature. The risk is that excessively thick grease may gum up the pawls.

Sheldon "Oil" Brown

jgedwa

Yup. As a shadetree hacker myself, I have always admired the way he presents his advice. It is so much easier to just give someone the best advice, but Sheldon usually explains why it is best, what other solutions might be, and what the limitations of those solutions might be. Bikes, because of their simplicity, lend themselves to this kind of hacking, and I appreciate the spirit with which he approaches them.

As an owner of a Sachs Spectro 7spd hub, I am curious here how this fares down the road. Check in after a lot of miles and let us know please.

jim

Betenoire

Thank you, Sheldon, for your reply. So what kind of oil would you use for the mechanism? I was thinking of not a very thin chain oil, but something like a motor oil perhaps? You don't think this will affect the drum brake?

Gumming up is something I have seen on this hub, hence the need to re-lubricate.

Betenoire

I will try to think of it

It's not me who's going to do the riding with this one, and it's my feeling that we will have to be patient... I think we should be happy if this thing is going to see 25km per week.

I gather your hub is sufficiently different from this one (Sachs Pentasport, older type, double cable) that they may not be entirely comparable, too.

Sheldon Brown

Motor oil is probably OK, but my favorite is Phil Wood Tenacious oil.

Shouldn't bother the brake if you don't overdo it, but I would advise against laying the bike on its left side right after oiling it.

Sheldon "Hasn't Used That Hub" Brown

Dan Burkhart 

With respect, I think I'd stick with grease for this hub. As you can see in the attached links, there is virtually no lip on the drive side to retain oil in the hub shell.

https://tinypic.com/fullsize.php?pic=...&capwidth=true
https://tinypic.com/fullsize.php?pic=...&capwidth=true
https://tinypic.com/fullsize.php?pic=...&capwidth=true

Betenoire

I don't think I could find that stuff here and it seems weird to import it from the USA just for a one-off.

Makes sense.

Thanks, makes me feel more special

Betenoire

Hey, did you steal my wheel?

Of course ou didn't, I left the cog on at the drive side.

Otherwise that looks *exactly* like my hub shell and mechanism.