Replacing my chain rings (help please)

[johnrburke2]

Hi all, I'm relatively new to cycling. My cycling is a 6 mile commute to/from work.

My bike (1992 Schwinn Impact, 18 speed) needs a new freewheel, chain and chain rings. I have found the freewheel and chain but am having a hard time understanding which chain rings to buy.

Any advice or direction y'all can share work me?

Thank you!

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[kramnnim]

Photo of the old cranks would help

[Peter P.]

You need to match the number of teeth on each ring, as well as the bolt circle diameter and number of bolt holes.

Bike shops have a template or a tool which can measure the BCD.

johnrburke2 is right; give us a photo of the bike, and detailed photos of the lettering on the chainrings and the lettering on the crankarm (front and back-there's usually engraving on the back), and we might be able to offer more specific help.

[johnrburke2]

Sounds like a plan. I will share these photos later this afternoon. Thank you.

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[bitpuddle]

Pictures would be fun just for nostalgia’s sake. I think those components could be either Shimano or Suntour.

[johnrburke2]

Will do. They are Shimano parts if that helps. Pictures to come later today.

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[bikinchris]

Man, an internet search for that year and model of Schwinn shows a wide range of different cranks and chainrings. Everything from welded chainrings to biopace.

[johnrburke2]

Man, an internet search for that year and model of Schwinn shows a wide range of different cranks and chainrings. Everything from welded chainrings to biopace.Thanks Chris, I guess I am not too sure what is compatible or not. If it does not violate forum policy, would you share a link of one or two that you would recommend?

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[oldpotatoe]

Thanks Chris, I guess I am not too sure what is compatible or not. If it does not violate forum policy, would you share a link of one or two that you would recommend?

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Like mentioned, a picture of the crank and many suggestions will be a result.

Google "1992 Schwinn Impact" and there are many bikes with various cranks.

[Ralph]

Probably much cheaper to just replace the whole crankset and BB.

[johnrburke2]

Here are the pictures of the crank set and freewheel. Any advice or direction on replacing these is appreciated. I'm not racing or doing group rides. Just commuting 6 miles to/from work.

Thanks!https://uploads.tapatalk-cdn.com/20190418/4ec6cf66aea694ad2757560a039ed957.jpghttps://uploads.tapatalk-cdn.com/20190418/a9a6c4c43ddba2c30bdd4f1c861d0351.jpghttps://uploads.tapatalk-cdn.com/20190418/137c525432452ebb64df2688ae7ca1a5.jpg

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[tsarpepe]

Kinda cool to see a bike like this here, among all the hi-tech weaponry and the boutique handmade objets d'art.

[cmbicycles]

You should just replace the crankset. Those look like all one piece. Something like below should work, depending on your bottom bracket spindle length... are those bearings in good shape, spin smooth?

Something like this on eBay might work
http://www.ebay.com/itm/312322076896

[oliver1850]

I can supply a cheap new Shimano 6 speed freewheel, have a box full of them 13-28 I think. Guessing that your present crank is 26/36/46 or close. If you are OK with slightly lower gearing, I have new FSA cranksets with bottom brackets that will be cheaper than the Shimano crank that cmb linked.

[Ken Robb]

Are we convinced that he needs new rings?

[bikinchris]

Are we convinced that he needs new rings?

That middle ring does look worn out. The asymmetric wear shows in the photo. The twisted, bent and shaped teeth were built in from the factory. They are called gates and they speed shifting between rings.
However, he can ride it like that in a pinch.it will shorten the life of the new chain, but shouldn't skip in hard pedaling, since it is more than 28 teeth. It would need to be much worse before it is a safety issue.

[ultraman6970]

WHere is this dude located?

[johnrburke2]

Thanks all, for the feedback. I live in Michigan, near the Detroit area. My ride is pretty flat, no big climbs or anything.

I am pretty sure the freewheel is 14-28, I can confirm that today. Could this be interchanged with one that is 13-28?

There bearings aren't in great shape on the crank. It's not choppy but nowhere near smooth.

Do I need to worry about specific teeth count or are they interchangeable?

--
1992 Schwinn Impact - Work commuter bike

[johnrburke2]

I can supply a cheap new Shimano 6 speed freewheel, have a box full of them 13-28 I think. Guessing that your present crank is 26/36/46 or close. If you are OK with slightly lower gearing, I have new FSA cranksets with bottom brackets that will be cheaper than the Shimano crank that cmb linked.Thanks Oliver. I'm not sure that I am involved in the intricacies enough to notice the difference of lower gearing. Do you need to know my teeth count to ensure it will work, or are they interchangeable?

--
1992 Schwinn Impact - Work commuter bike

[charliedid]

I can't seem to remember for sure but are those rings riveted and not replaceable?

I'd look into a new crank and BB

[johnrburke2]

I can't seem to remember for sure but are those rings riveted and not replaceable?



I'd look into a new crank and BBThey may be riveted. I have not taken it apart far enough to tell yet. is there anything in specific I need to pay attention to when replacing the crank set?

would the FSA crank set that Oliver mentioned above be interchangeable? If so, I may support the forum community and just pick them up from him.

Excuse my ignorance, I'm the new guy, what is a BB?

Oliver, does this look like something you can hook me up with new parts for?

--
1992 Schwinn Impact - Work commuter bike

[oldpotatoe]

Kinda cool to see a bike like this here, among all the hi-tech weaponry and the boutique handmade objets d'art.

Yup, needs to be "copy to" 'bike gadget ya have to have'..have to have a 'bike' to ride, not much else.

Looks like a 110/74 bolt diameter crank. Probably cheaper to just change the crankset if you need new chainrings.
BB=bottom bracket and 'matched' to crank..type of interface and length/type, etc.

Do you have a bike co-op around? Place with tools, knowledge and used parts?

[cp43]

They may be riveted. I have not taken it apart far enough to tell yet. is there anything in specific I need to pay attention to when replacing the crank set?

would the FSA crank set that Oliver mentioned above be interchangeable? If so, I may support the forum community and just pick them up from him.

Excuse my ignorance, I'm the new guy, what is a BB?

Oliver, does this look like something you can hook me up with new parts for?

--
1992 Schwinn Impact - Work commuter bike


For general info about bike parts and maintenance check out:
https://www.sheldonbrown.com/

It's a great resource, and explains what different parts are, and how they work together.

Chris

[charliedid]

Yup, needs to be "copy to" 'bike gadget ya have to have'..have to have a 'bike' to ride, not much else.

Looks like a 110/74 bolt diameter crank. Probably cheaper to just change the crankset if you need new chainrings.
BB=bottom bracket and 'matched' to crank..type of interface and length/type, etc.

Do you have a bike co-op around? Place with tools, knowledge and used parts?

This ^

[dddd]

I'll second that I don't see anything that looks worn out. Certainly not the chainrings.

I myself would replace only the chain and then test out how that works.

If there is any runout of ther chainrings at the front derailer cage, I typically woud use a short length of wood dowel as a drift and strike with a hammer until the chainrings run true. Also inspect for any bent teeth, but here they are steel and thus quite resistant to bending.

[oliver1850]

Thanks Oliver. I'm not sure that I am involved in the intricacies enough to notice the difference of lower gearing. Do you need to know my teeth count to ensure it will work, or are they interchangeable?

--
1992 Schwinn Impact - Work commuter bike

The cranks I have are 22/32/44. Should be OK unless you feel like you need higher gears now. You may have to adjust the height of the front derailleur.

The freewheel I have is 14-28. This one:

https://www.ebay.com/itm/SHIMANO-6-SPEED-MF-TZ20-14-28T-BROWN-MTB-HYBRID-CRUISER-BICYCLE-FREEWHEEL/321668854750?epid=691117408&hash=item4ae4f533de:g:ec8AAMXQPd1RHYQd