J B

Hope someone can help me!
I have a 1980 Soma Sport 10 speed that I just got out of my basement after 26 years. Tested it and found that everything works fine.

I removed the cranks (Maxy) and chainrings (With a Park Tool CCP-2) for cleaning and then replaced them. I am now having problems shifting from the small front chainring to the large. It will grind and make noise then will go to the large chainring. If I shift going slow and with no resistance it will shift fine.

Is there any way to confirm that the crank is all the way to the home position? I tightened the nut as far as I can (I think) If I try to tighten it any further I am afraid I will strip something. I did try to adjust the high limit screw on the (Front: SUNTOUR Compe-V) derailleur a little at a time until finally the chain got thrown over the large chainring. I then adjusted it back to keep this from happening but it still wants to grind and make noise with the least amount of resistance.

I am not convinced that the crank is all the way home. Like I said, I didn't have this problem before I removed these parts. All gears and chain are in like new condition. The bike only had 67 miles on it when I parked it 26 years ago. I also degreased and then lubed the chain with ProLink chain lube.


Thanks for any help with this,
J B

miamijim

Sounds A-ok to me.

Proper technique for an older bike is to back off on the pedal pressure and shift gently. All other techniques will grind while shifting. Obviously you'll want to make sure the derailleur is positioned correctly.

kinda like shifting a manual tramsmission car. Back off on the gas, shift smoothly, let clutch out.

J B

miamijim,
Thanks but now it's a little more extreme then that. Starting to nick up the large chainring. And I have to shift with no resistance to keep from damaging it completely.

J B

miamijim

Welcome to 3 decades ago.......

Proximo

Sounds like you have a square tappered spindle on your bottom bracket. You might try greasing the spindle before putting the crank arms on. Also, use a torque wrench to tighten the crank bolt down. For one, you'll know when its tight enough. The long arm of the torque wrench will also give you more leverage if necessary to get it good and tight. I have no idea what the torque spec on your bolt should be but looking at the torque table in Zinn and the Art of Road Bike Maintenance, it looks like 300 inch-lbs should be safe but your mileage may vary.

bluehair

Proximo is correct. It sounds like your chainrings are sitting more outboard than they were. I'm assuming that you did absolutely nothing to the front derailleur. It takes more pressure to tighten crank bolts than most people can generate with an 8" wrench. Grease the spindle and use a torque wrench. 300 in. pounds should do it.

2372ighost

Clean and lube the front DR and it's cable, sluggish movement of the dr will also give this exact problem.
Both my 84 schwinn and 76 Juenet suffered this problem(Excessive grinding upshift) It will grind and you do have to back off a little, but shifting is crisper.

J B

Proximo, thanks for your response,
Yes square tapered spindle. Think I will try as you suggest. I thought of doing this at first but I read somewhere the metal aluminum is self lubricating and it is not necessary. I will use a torque wrench as well. I did find a "Bicycle Torque Specifications" list here: but the torque is only listed for a crank bolt not a nut. I would think a nut would have a lower torque.



Thanks again,
J B

Baggsy

Is it an optical illusion, but that nut doesn't look like it's far enough on there...shouldn't it be flush with the bolt-end?

J B

That is just a picture from the Park Tool website. Click Here

Thanks,
J B

cyccommute 

You didn't accidently turn the spindle around, did you? Old bikes had very asymetrical crank spindles.

Proximo

The Zinn table lists anywhere from 304 to over 400 inch-lb for different crank bolts so I just pulled 300 of the top of my head as a likely safe number that should be close enough to minimum torque spec to give you an idea if that is the problem.

I like cyccommute's suggestion to make sure the bottom bracket isn't installed backwards. If so, that would likely explain everything.

J B

Guys, yeah... But I removed them just to clean and I did them one at a time. So that can't be it. I even put the chainrings on the way they came off. Even bolt for bolt.

I will put a dab of lithium grease on there tonight and let you know what happens.

Thanks again,
J B

cyccommute 

What we got here, Pilgrim, is a failure to communicate!

If this is the old fixed cup/adjustable cup bottom bracket, did you accidently reverse the spindle (there's only one, hence the failure to communicate) when you reinstalled it. I doubt that it would cause the kind of problem that you are having but stranger things have happened.

Proximo

Sounds like you only removed the crank arms and not the bottom bracket itself so you couldn't have re-installed it wrong.

cyccommute 

You removed the chainrings? Did you put them on backwards? There's a recess in most chainrings where the bolts go. Perhaps, if you put them on backwards the chainrings are now too far outboard. There also might be a different bevel on the chainrings from the front and rear to aid in chain pickup/drop.

I grasping at straws now

J B

cyccommute,
Like I said in my last post
"I even put the chainrings on the way they came off. Even bolt for bolt."
I put all that info above to avoid the word "anal".

Ok there. I said it.

But I will check all this anyhow. One never knows for sure!

J B

JanMM

Park Tool suggests not greasing square taper spindles. I've never done that (based on similar advice a long time ago) and always been able to get things apart later.

J B

Just wanted to report in:
I did not want to use lube on the spindle. I realize aluminum acts kind of a self lubricating with steel. But I was not convinced that the crank was going all the way home. So... With a thin skin of lithium grease, I gave it another shot by feel. couldn't get a hold of a torque wrench.

All assembled and ready to test............. But wait!!!
I thought it best to put some air in the tires and blow the hell out of my front tube!!!
Replace that and I was on my way.

Shifted to the large chainring and threw the chain over the large chainring. This is what I was hoping for because that means the crank and chainrings went in further. Adjusted the high limit screw in a tad and everything is working much better. Although, I hate to say it. I think in needs to go in a little more. But I know this was the problem. I would like to thank Proximo, for giving me a push to use some lube. And to all you guys for chiming in and even a little straw grasping.

Thanks again,
J B