Sjtaylor

I just scored a 1984 Miyata 1000 in pretty neglected condition. I just started a frame up rebuild. The bottom bracket was crunchy before disassembly and the removed spindle has pitted bearing journals. Not sure where to get an exact replacement spindle but I have a couple spindles in my stash. I have one that matches length very well but is slightly pitted too. I have a second one that looks like new but is 1/8” to 3/16” shorter on each end. I’d like to use the shorter replacement spindle.

I think there is plenty of room to cozy up the cranks a bit but not sure how the chain line will be affected. Are there specific things to consider when changing spindle length?

Also, the chain is very, very worn. My chain wear gage rattled around in the chain. I even see undue wear in the cluster cogs. I do have a like new donor cluster that has six cogs instead of five. I have never removed a cluster or serviced an older style rear hub. I’d have get the appropriate tool. Is a better option to have a local shop service the rear hub or invest in the tools I would need? Can you recommend a good video on the subject?

I took a photo of the spindles. The center spindle is the one I want to replace.

Bill Kapaun

The FDER may not reach the inner ring with too short a spindle.
There should be a "code" on the spindles such as 3P, 3S, 3?.....
Post those and I should be able to provide the offsets of each.

squarenoise 

So I had the same problem when I bought my '84. Actually worse because the cups were pitted as well. I don't think the BB had ever been serviced considering the remaining grease was basically petrified. Anyhow, are your cups in good shape? If yes, you could always try the shorter spindle, but I think it might be too short.

I ended up buying a sealed bottom bracket with 127mm spindle from Velo Orange and it worked out great. No additional spacer (to make it asymmetrical) needed.

If you go from 5 to 6 speed, I think you'll definitely want to stick with the longer spindle length for better chainline. If your wheel is dished the same as mine, you should have enough room for the six speed freewheel without extra hassle.



Freewheel removing/replacing is fairly straight forward and the tools, although several varieties, are fairly inexpensive. Here's a good video on freewheel removal:
If your 1000 has the original wheelset, the hubs are sealed bearing Suntour and require harder to find specialty tools to fully service and/or replace the bearings. If the feel smooth, I would leave as is. If they feel grimy, it might be time to replace the bearings which might seem complicated depending on your skill/comfort level. There are a few threads here that cover this.

https://www.bikeforums.net/classic-v...idge-hubs.html
https://www.bikeforums.net/classic-v...t-replace.html
https://www.bikeforums.net/classic-v...-hub-tool.html
https://www.bikeforums.net/classic-v...-pictures.html
https://www.bikeforums.net/bicycle-m...tery-tool.html

Sjtaylor

The spindle is labeled...

N-B
U3
84 -F

Will I be able to purchase a new replacement or should I look for a used one?

Thanks.

dedhed

Personally if I have to buy replacement spindle or cups I throw in a sealed cartridge. Tange LN, Shimano UN55 or Un26

Phil_gretz

It's all about chain line. The crankset manufacturer specified a particular spindle length. This length can usually be found on VeloBase if you know your crank. Adjusting chain line for 5-to-6 speed conversion should be minimal, at most 2.5mm outboard. I'd ignore that, personally. Note that your original spindle is asymmetrical, meaning that the drive side crank is placed farther away from the centerline than the non-drive side crank. This shouldn't matter if you choose to get a symmetrical cartridge style bearing, which I would also recommend. But you can shim the drive side of the cartridge to split the difference between the asymmetrical lengths.

Bill Kapaun

https://www.huskybicycles.com/bicycl...-c52-r405.html

You didn't list the 3? code for the other 2, so I can't compare offsets. Thus, I'm done.

Sjtaylor

Thanks for the link. I knew nothing about bottom bracket spindles when I started this thread. I learned a lot. I compared the offsets of the two in my stash. Sorry I didn’t list them too.

Ive measured the chain line using a straight edge along the chainring for another project. I think I might change the cluster to the six or seven cogged cluster, temporarily install the old spindle and see how the chain line looks. I might need another offset to get it just right. It will be fun.

This bike had thick dried greasy dirt caked on every mechanical component and in every crevice. I need to slow down and focus on cleaning parts. I tend to get ahead of myself trying to get a new project rideable. The rebuild is as fun as the first few rides. Need to enjoy it. The Miyata frame is worth taking it slow.

Thanks again.