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Discussion Starter · #1 ·
I am doing my first bike build and I have run into my first real problem. I think the rear triangle might be a little bent towards the drive side. I'm basically done with the build and I mounted the chain. What I'm seeing is when the chain is on the small chainring on the front and the small on the back, the chain is rubbing on the inside of the large chainring. It is not rubbing on the front der. but on the side of the large chainring. What I also notice is the space between the rear drop outs is a little tight and I need to pull them a little open to fit in the rear wheel. Maybe 3-5mm max.

All the components are new Ultegra and the frame is a Serotta steel Fierte I bought off e-Bay, but it has never been built up.

Is it common for steel frames to be just out of wack when new & shipped by UPS? I would think my LBS can use a frame tool & bend it back into shape if needed for very little money.

Thoughts?
 

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Jim the Giant rider said:
I am doing my first bike build and I have run into my first real problem. I think the rear triangle might be a little bent towards the drive side. I'm basically done with the build and I mounted the chain. What I'm seeing is when the chain is on the small chainring on the front and the small on the back, the chain is rubbing on the inside of the large chainring. It is not rubbing on the front der. but on the side of the large chainring. What I also notice is the space between the rear drop outs is a little tight and I need to pull them a little open to fit in the rear wheel. Maybe 3-5mm max.

All the components are new Ultegra and the frame is a Serotta steel Fierte I bought off e-Bay, but it has never been built up.

Is it common for steel frames to be just out of wack when new & shipped by UPS? I would think my LBS can use a frame tool & bend it back into shape if needed for very little money.

Thoughts?

OK, that chain rubbin' on the chainring is normal. You're cross geared in the small/small combination. I think this is a common with the 9-10 speeds and shorter chainstays. I can't run in the small/small combo either.

I don't know about the dropout spacing issue. I'm sure someone will chime in with some useful info on that.
 

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Measure the dropouts without the wheel installed to start with...maybe it's designed along the "gnot rite" line of thinking at 132.5 or something. Not a big deal on a steel frame in any case. Not unusual for chainring rub in the small/small you describe.
 

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No. A Serotta road frame should most assuredly have 130mm dropout spacing. The 132.5 is strictly a Surly thing, as far as I know. If you have to shove the wheel into the frame (and it truly has never been built up), then you should have a shop check the frame alignment and the dropout spacing. If your chainline is compromised in some way, it'll manifest itself with crappy shifting - especially if you're running a triple.
 

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Yes, this is very normal.
 

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Discussion Starter · #6 ·
I have thought about this some and this is what I'm thinking, but I'm not sure if steel flexes this way. The rear drop out is about 3-5mm tight. If non-drive side of the seatstay/chainstays got bent in about that much and then I "flex" it open to fit in the wheel, both sides are splitting the difference of the flex so it is kicking out the drive side just enough to cause the rub?
 

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stay out of the small area of the cassette when in the small chainring. there is nothing wrong with the frame. As Mersault stated above. you have cross geared it. you would over flex the chain if you went to the big chainring and large cassette also, try to avoid that combo as well.
 

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Reading for comprehension

Jim the Giant rider said:
I have thought about this some and this is what I'm thinking, but I'm not sure if steel flexes this way. The rear drop out is about 3-5mm tight. If non-drive side of the seatstay/chainstays got bent in about that much and then I "flex" it open to fit in the wheel, both sides are splitting the difference of the flex so it is kicking out the drive side just enough to cause the rub?
Are you not reading the other posts? It is EXTREMELY common for the chain to rub the outer ring when in the small-small combination. In fact, with 9s or 10s systems, it would be unusual if you didn't have the rub. Whether your frame is bent or out of line is a separate issue. You can easily measure the width of the rear dropouts to see if your frame is at the proper 130 mm spacing. If you run a tight piece of string or fishing line from one rear dropout, around the head tube, and to the other dropout, you can measure the distance from the string to the seat tube to insure that the frame is "square."
 

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gmcastil said:
No. A Serotta road frame should most assuredly have 130mm dropout spacing. The 132.5 is strictly a Surly thing, as far as I know. If you have to shove the wheel into the frame (and it truly has never been built up), then you should have a shop check the frame alignment and the dropout spacing. If your chainline is compromised in some way, it'll manifest itself with crappy shifting - especially if you're running a triple.
Serotta never made a 126? FWIW I wasn't referring to mid point of 135/130 spacing specifically...and it's not just a Surly thing, there are several frames that come with a midpoint in steel to allow different spaced hubs, altho mostly that's the 132.5 thing. Without a measurement of the dropouts to begin with, let alone verification of his current hub spacing, or frame alignment,it's just mental masturbation anyways....
 

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Discussion Starter · #10 ·
frame is bent

Kerry Irons said:
Are you not reading the other posts? It is EXTREMELY common for the chain to rub the outer ring when in the small-small combination. In fact, with 9s or 10s systems, it would be unusual if you didn't have the rub. Whether your frame is bent or out of line is a separate issue. You can easily measure the width of the rear dropouts to see if your frame is at the proper 130 mm spacing. If you run a tight piece of string or fishing line from one rear dropout, around the head tube, and to the other dropout, you can measure the distance from the string to the seat tube to insure that the frame is "square."
The drop out is 127.5mm - so 2.5mm too tight. When the shop checked the frame alignment they said that one of the rear stays was flexed in by that amount. He said I could find someone to bend it back, but he suggested I send it back to Serotta and have then do it. They will correct it and in the process not create another frame problem.

I understand 10s do tend to rub. However, I have the exact same frame, exact same components, exact same wheels (different color bike, thou) and I have very nearly no crosschain rubbing. That is why I noticed it so much. Just for reference, I'm running all ultegra 6600, 39/53 crank, 12-25T cassette and the chainstay length is 41.5cm measured on the frame axis.
 

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Jim the Giant rider said:
The drop out is 127.5mm - so 2.5mm too tight. When the shop checked the frame alignment they said that one of the rear stays was flexed in by that amount. He said I could find someone to bend it back, but he suggested I send it back to Serotta and have then do it. They will correct it and in the process not create another frame problem.

I understand 10s do tend to rub. However, I have the exact same frame, exact same components, exact same wheels (different color bike, thou) and I have very nearly no crosschain rubbing. That is why I noticed it so much. Just for reference, I'm running all ultegra 6600, 39/53 crank, 12-25T cassette and the chainstay length is 41.5cm measured on the frame axis.
I agree with your dealer. I've bent a few frames around over the years and it isn't easy. I wouldn't be willing to do it to someone else's frame. By the way, I've been riding bikes for about 1/2 a century and I've never had a chain contact two chainrings at the same time except while a shift is occurring - not on old bikes or current bikes or triples or doubles. I wouldn't view it as normal or ordinary at all. If the chain contacts the derailleur then that is common and easy to adjust. But it shouldn't contact two chainrings at the same time.
 
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