Chain Ring Problem
08-25-06, 12:57 PM
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Chain Ring Problem
Bought a 1998 Trek 520 on ebay. I am learning (miserably failing) to wrench. On other bikes, I overhauled the front and rear hubs. I took the chainrings off and thought I would check out the bottom bracket while I changed the gearing to something a little better for touring. Used the BB2 and a large wrench and the Blue Book. Broke some kind of ring on the non-drive side and am waiting for help when I see the boss man. (He won't be happy) Will he be able to use a pipe or something, or do I have to go to the lbs and have them drill it out??? I would rather bypass the husband, if he really doesn't have to bail me out. Then again, I don't want to guys in the bike shop to see what I did either.
Chainrings. I ordered some that fit both 130 and 110 bcd (heavy rings!). The 74 bcd 24 tooth granny went on without a problem. The middle 38 tooth went on without a problem. The outer ring 48 does not sit in the step down (?) of the spider of a Shimano 105. Because the rings fit both sizes bcd, there is a lot of extra metal. Do I have to send this back to Harris Cyclery or did I order the wrong part???
Thanks, Debbie
Chainrings. I ordered some that fit both 130 and 110 bcd (heavy rings!). The 74 bcd 24 tooth granny went on without a problem. The middle 38 tooth went on without a problem. The outer ring 48 does not sit in the step down (?) of the spider of a Shimano 105. Because the rings fit both sizes bcd, there is a lot of extra metal. Do I have to send this back to Harris Cyclery or did I order the wrong part???
Thanks, Debbie
08-25-06, 06:44 PM
#2
ride, paint, ride
Is there any way you can post a picture of the broken ring on the non-drive side? I'm not clear on what that was. Is it part of the bottom bracket? The lockring maybe? Or is it on the crank?
As for the large chainring, if it won't fit and can't be made to fit, Harris will take it back in exchange. They're very good about that. Is it steel? If a magnet sticks to it, it's steel. If it's meant to work on a 110 BCD, seems like it should work, though there may be something different about the spider on your crank. Again, a picture would be good if you can do that.
As for the large chainring, if it won't fit and can't be made to fit, Harris will take it back in exchange. They're very good about that. Is it steel? If a magnet sticks to it, it's steel. If it's meant to work on a 110 BCD, seems like it should work, though there may be something different about the spider on your crank. Again, a picture would be good if you can do that.
08-25-06, 07:23 PM
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just 5 more miles
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"The middle 38 tooth went on without a problem. The outer ring 48 does not sit in the step down (?) of the spider of a Shimano 105."
The middle ring and the outer ring use the same bolt to attach them. The bolt passes through both rings and then is tightened. Also a dab of anti - sieze on the bolts threads before reassambly is a good thing. Does this help?
Vin
The middle ring and the outer ring use the same bolt to attach them. The bolt passes through both rings and then is tightened. Also a dab of anti - sieze on the bolts threads before reassambly is a good thing. Does this help?
Vin
08-27-06, 06:58 AM
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Okay, here is an update. I tried to take pictures with my cell phone and the pictures came out too light so I will try to explain.
Chainring: I screwed down the 74 BCD granny ring. The 38 Middle ring, I lined up with the holes on the inside of the spider. The 48 outer ring will not fit. A typical ring is about 1 inch around the outside circumference with tabs dropping into the center with holes to be attached to the crank. On the rings that I bought, the outside diameter is about 3.5 inches of metal and in that space are drilled holes for 130, then there are tabs that are further inside the circle for 110. The inside diameter is not open large enough to fit on the spider drop outs. I will have to order from somewhere else. The chainrings are 6061 aluminum, but they weight at least twice as much as the original rings. They are called rocket rings.
The bottom bracket: My brother came over and helped me. I was trying to unscrew the non-drive side which the book says to do. I broke a part of the plastic ring which is really about a 1.5 inch screw in cup(?). My brother used a cheater bar (large pipe) and took the bottom bracket off on the drive side. That side showed a small metal circle which was actually the end of the bottom bracket. The part that I broke was about 1 inch off the plastic/light metal cup which was able to be screwed out once the bottom bracket was removed. I looked up pictures of lockrings and it is not a lockring. What do you think it is? I was trying to use the BB2 tool with an adjustable long handled wrench and I hit it with a hammer. My brother said I hit it too hard and that is what caused it to slip and brake the end off. I may be able to use it, but what is the part??
Chainring: I screwed down the 74 BCD granny ring. The 38 Middle ring, I lined up with the holes on the inside of the spider. The 48 outer ring will not fit. A typical ring is about 1 inch around the outside circumference with tabs dropping into the center with holes to be attached to the crank. On the rings that I bought, the outside diameter is about 3.5 inches of metal and in that space are drilled holes for 130, then there are tabs that are further inside the circle for 110. The inside diameter is not open large enough to fit on the spider drop outs. I will have to order from somewhere else. The chainrings are 6061 aluminum, but they weight at least twice as much as the original rings. They are called rocket rings.
The bottom bracket: My brother came over and helped me. I was trying to unscrew the non-drive side which the book says to do. I broke a part of the plastic ring which is really about a 1.5 inch screw in cup(?). My brother used a cheater bar (large pipe) and took the bottom bracket off on the drive side. That side showed a small metal circle which was actually the end of the bottom bracket. The part that I broke was about 1 inch off the plastic/light metal cup which was able to be screwed out once the bottom bracket was removed. I looked up pictures of lockrings and it is not a lockring. What do you think it is? I was trying to use the BB2 tool with an adjustable long handled wrench and I hit it with a hammer. My brother said I hit it too hard and that is what caused it to slip and brake the end off. I may be able to use it, but what is the part??
08-27-06, 02:28 PM
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the rocket rings are very inexpensive and therefore probably don't have great tolerances. a little filing will probably make them seat properly, assuming this is the issue i envision from your description.
08-27-06, 02:40 PM
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Originally Posted by outashape
Okay, here is an update. I tried to take pictures with my cell phone and the pictures came out too light so I will try to explain.
Chainring: I screwed down the 74 BCD granny ring. The 38 Middle ring, I lined up with the holes on the inside of the spider. The 48 outer ring will not fit. A typical ring is about 1 inch around the outside circumference with tabs dropping into the center with holes to be attached to the crank. On the rings that I bought, the outside diameter is about 3.5 inches of metal and in that space are drilled holes for 130, then there are tabs that are further inside the circle for 110. The inside diameter is not open large enough to fit on the spider drop outs. I will have to order from somewhere else. The chainrings are 6061 aluminum, but they weight at least twice as much as the original rings. They are called rocket rings.
The bottom bracket: My brother came over and helped me. I was trying to unscrew the non-drive side which the book says to do. I broke a part of the plastic ring which is really about a 1.5 inch screw in cup(?). My brother used a cheater bar (large pipe) and took the bottom bracket off on the drive side. That side showed a small metal circle which was actually the end of the bottom bracket. The part that I broke was about 1 inch off the plastic/light metal cup which was able to be screwed out once the bottom bracket was removed. I looked up pictures of lockrings and it is not a lockring. What do you think it is? I was trying to use the BB2 tool with an adjustable long handled wrench and I hit it with a hammer. My brother said I hit it too hard and that is what caused it to slip and brake the end off. I may be able to use it, but what is the part??
Chainring: I screwed down the 74 BCD granny ring. The 38 Middle ring, I lined up with the holes on the inside of the spider. The 48 outer ring will not fit. A typical ring is about 1 inch around the outside circumference with tabs dropping into the center with holes to be attached to the crank. On the rings that I bought, the outside diameter is about 3.5 inches of metal and in that space are drilled holes for 130, then there are tabs that are further inside the circle for 110. The inside diameter is not open large enough to fit on the spider drop outs. I will have to order from somewhere else. The chainrings are 6061 aluminum, but they weight at least twice as much as the original rings. They are called rocket rings.
The bottom bracket: My brother came over and helped me. I was trying to unscrew the non-drive side which the book says to do. I broke a part of the plastic ring which is really about a 1.5 inch screw in cup(?). My brother used a cheater bar (large pipe) and took the bottom bracket off on the drive side. That side showed a small metal circle which was actually the end of the bottom bracket. The part that I broke was about 1 inch off the plastic/light metal cup which was able to be screwed out once the bottom bracket was removed. I looked up pictures of lockrings and it is not a lockring. What do you think it is? I was trying to use the BB2 tool with an adjustable long handled wrench and I hit it with a hammer. My brother said I hit it too hard and that is what caused it to slip and brake the end off. I may be able to use it, but what is the part??
Bottom bracket is the axle & bearing setup as a whole.
Bottom-bracket shell is the part of the bike's frame that the bottom bracket threads into.
Cartridge bottom brackets are the type you're describing, like in this picture:
The cartridge bottom bracket usually has one end where there's a metal "flange" that goes firmly against the frame (this is the metal ring you saw on the drive side). The other end of the cartridge (the cylindrical silver part in this photo) is supported by a plastic or metal "cup" that threads in until it's snug. That's the part you broke. You can get another one from a bike shop.
Fixed cup In the picture above, the cartridge has cups at both ends. The one with the flange on it is the "fixed cup," where "fixed" means "securely fastened." That's the side that gets firmly threaded into the frame until the flange is really tight against the frame, which is why you needed a lot of leverage to remove it. Some cartridge bottom brackets basically have the fixed cup built into the cartridge, in which case the cartridge has threads and a flange right on it.
Also, here's a link to a good 48-tooth outer chainring that has very high-quality material and is a 110mm bolt-circle diameter ("BCD"): https://www.cambriabike.com/shopexd.asp?id=10219 The shifting on these is not as good as the Shimano XT/XTR version (https://www.cambriabike.com/shopexd.asp?id=8596) but they have unbeatable longevity due to the nickel plating on top of 7075 aluminum with all full-height teeth. 7075 aluminum is better in my opinion for chainrings than 6000-series aluminum, due to its hardness, which helps resist gouging and jamming.
Last edited by mechBgon; 08-27-06 at 03:07 PM.
08-28-06, 01:21 AM
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Mechbgon, Thanks so much. I didn't understand that the cup was a separate part of the cartridge bottom bracket. All the pictures I've seen on Nashbar, Harris and even the Quality Catalog on Harris, showed the cartridge bottom bracket as one piece. The cambriabike.com website shows the cartridge separate from the cup. I wasn't sure if I had to order new cranks to get the new part or a new cartridge bottom bracket.
I don't have a grinder and that is really too much for me, so I will be sending the chainrings back. Since the middle chain ring was really worn down on the ebay Trek 520 bike when I took the rings off and took all the thick oil off the teeth, I had to order a granny and a middle ring rather than just changing out the 30 tooth granny for a 24 tooth granny. I decided to order a new large ring and lower the front derailer for a touring setup. Now that I have to order a bottom bracket, I may order a cheap crank for around $69 for an ATB Treking Crank on Nashbar and change out the granny 26 to my new 24 tooth, Then I'll get to learn about chainline issues. I'll be changing the spindle size from a 118 to I think a 121. What a great winter project!
I don't have a grinder and that is really too much for me, so I will be sending the chainrings back. Since the middle chain ring was really worn down on the ebay Trek 520 bike when I took the rings off and took all the thick oil off the teeth, I had to order a granny and a middle ring rather than just changing out the 30 tooth granny for a 24 tooth granny. I decided to order a new large ring and lower the front derailer for a touring setup. Now that I have to order a bottom bracket, I may order a cheap crank for around $69 for an ATB Treking Crank on Nashbar and change out the granny 26 to my new 24 tooth, Then I'll get to learn about chainline issues. I'll be changing the spindle size from a 118 to I think a 121. What a great winter project!
