Is there any way to test internal gear hubs without building a wheel? (SG 7R42)

[Tsarbombaad]

I have a rather old SG-7R42 shimano nexus inter7 gear hub from a job lot, and I would like to know more about it. Below attached are pictures of the gear hub. I contacted my LBS who said that there's probably a way to benchtest them, but they don't know how to.

https://imgur.com/a/WXpNPdR











Which cassette joint does this internal gear hub take? there's also a black thing that has "Adjust in gear 2" on it included in my job lot, but I don't know what it is. Would this internal gear hub work well with modern shimano 7 speed gear shifters?

Is there a way to bench test these internal gear hubs, and do I need to get the shifter and casette joint to benchtest them? Thanks!

[plancashire]

Here are the instructions for Shimano SG-7R42: https://manualzz.com/doc/53870851/shima ... structions. You wrote SR in the text and SG in the title.

To test all you need to do is set it up so you can change gears, turn the sprocket a number of revolutions and count the revolutions of the body, on which the wheel is built. Check you have 7 gears. Adding load to the hub would be harder, which you might need to do to check for wear by listening for noises.

[Post edited by moderator for breach of forum guidelines.]

[Tsarbombaad]

Here are the instructions for Shimano SG-7R42: https://manualzz.com/doc/53870851/shima ... structions. You wrote SR in the text and SG in the title.

Apologies for the misspelling, I have changed it to the correct product code. The manual you linked me only specifies what type of non-turn washer the hub uses in regard to if the dropout is reversed or normal. I've done more looking and I've found that the cassette joint SG 7R42 is compatible with is the CJ-NX10/CJ-NX40 (https://sheldonbrown.com/shimano/docume ... 41,42).pdf) , but there's no information about what shifters are compatible with it.

I believe this is the manual from shimano's website https://si.shimano.com/en/pdfs/si/7R42A ... 00-ENG.pdf
But there's no information about which shifters are compatible.

I already have some non-turn washers for sturmey archer gears, and the axle size this hub gear seems to match that of sturmey archer hubs. Would using said non-turn washers create problems for the hub?

[plancashire]

Sorry, I can't comment with any knowledge about the non-turn washers, but if they just have a flattened round hole and two lugs that point into the drop-out, then if they are the same thickness or similar enough to be accommodated by a little frame play, then they should be OK, but check angles here: https://www.sheldonbrown.com/nexus-mech.html#washers.

For checking the shifter compatibility you could try estimating the length of cable you need to pull to change from 1 to 7 on your hub, then find a shifter and compare its pull. This assumes that the steps are the same. All the Shimano shifters I see in the workshop seem to have evenly spaced numbers in the dial but I do not know if the mechanism pulls equal amounts of cable.

There's lots of detail on this same page: https://www.sheldonbrown.com/nexus-mech.html about shift adjustment.

BTW, the forum moderator edited my post because I used an abbreviation I hadn't realised could be interpreted as a swear word. Sorry to all.

[Brucey]

N7 is LGN and requires 5mm cable pull per shift apart from 5-6 which needs ~6.5mm.
CJ is the same as 4s
You can sometimes tell if a hub is bad outside the bike but IME the only way to tell if it is good is to ride it

cheers
Brucey