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Old 10-01-10, 06:11 PM   #1
mykn
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Front Derailleur Mount?

Hey Everyone!

I'm building up an old 1986 Cannondale SR400 frame and I'm almost finished except for the front derailleur. It looks like I need some type of mount that goes between the bolts on the frame and the derailleur. Does anyone know what this is called and where I might get one? If it's too much of a hassle, would it make sense to buy a clamp adapter and attempt to get that to work? If I remove the bolts from the frame it looks like I might be able to get a clamp attached.

Thanks!

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Old 10-01-10, 06:15 PM   #2
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There should have been a steel (stainless?) tab with a slot that bolted to the frame at that location to mount a period front derailleur on.
You might be able to still buy it from Cannondale but you might also find it for sale at eBay.

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Old 10-01-10, 06:18 PM   #3
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Should I try contacting Cannondale @ their 1800BikeUSA number or is there a better place to call/email?
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Old 10-01-10, 06:25 PM   #4
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Should I try contacting Cannondale @ their 1800BikeUSA number or is there a better place to call/email?
Wouldn't hurt to try that but you can also google in the internet "Canonndale spare parts" and you might get both Cannondale USA and parts distributor contact information for you email or call up.

Good Luck, hope you find it soon!

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Old 10-01-10, 07:53 PM   #5
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After doing a google image search, this is the thing that I need



Does anyone know what it's called?
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Old 10-01-10, 08:35 PM   #6
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That is a "braze-on" type derailleur hanger. If you buy a replacement the holes in the hanger must match the holes in the seat tube.
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Old 10-02-10, 02:59 PM   #7
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Ok, spoke to a LBS that is a Cannondale dealer and they know the part and are going to see if it's possible to order one. We tried to see if a 1 1/4 inch seat tube clamp would fit and it does fit just not where the screw holes are (where it needs to be).

The mechanic I talked to said that it looks like the braze-on hanger is screwed into rivnuts in the frame and that it would be possible to drill them out to remove them. If we did that, the clamp would fit in the correct location. I would assume that the rivnuts do not provide any structural integrity to the frame but I'm unsure. Does anyone know if it would be safe to drill the rivnuts and use a clamp instead?
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Old 10-03-10, 10:29 AM   #8
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I would suggest that you only drill out the derailleur mount rivnuts as a last resort as it is a shame to do that to a classic Cannondale and end up with two useless holes on the downtube of your frame. See if youc can find an internet site for Cannondale owners/riders can help you. There should be a dedicated group out there that will be glad to help other classic Cannondale owners to get their bikes back together again. some of them might even have spares of what part you need and will be willing to sell you or even just give you one or theirs.

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Old 10-03-10, 02:35 PM   #9
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That would be the extreme last resort, its a beautiful frame and I don't want to do anything unnecessary but it needs to be ridden The riding season is coming to a close so I'm not in a hurry to get the FD on it so I'll try to find the appropriate part. If it does come to drilling out the rivnuts, do you think it's safe to ride with the rivnuts removed and if it would then be safe to ride with the clamp on FD?

Thanks!
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Old 10-03-10, 05:00 PM   #10
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That would be the extreme last resort, its a beautiful frame and I don't want to do anything unnecessary but it needs to be ridden The riding season is coming to a close so I'm not in a hurry to get the FD on it so I'll try to find the appropriate part. If it does come to drilling out the rivnuts, do you think it's safe to ride with the rivnuts removed and if it would then be safe to ride with the clamp on FD?

Thanks!
It should be safe to ride it with the rivnuts removed (just make sure the person drilling them out knows what they are doing and do not damage the seat tube in any way while doing it. Aluminum is sensitive to nicks and other imperfections that might introduce what's called stress risers that could propagate into cracks later) as the nuts themselves do not provide any added reinforcement to the down tube at the holes and you could hold off and take your time getting the right parts later, but you know how that tend to go with most of us when later might mean a few years when it might be even be much harder to find the parts for it anymore, plus a clamp around the seat tube might scratch and marr the paintjob in that area too. I guess I'm speaking as a C&Ver and am sensitive about restoring classic bikes like your Cannondale "correctly and completely", but you are also very right about the bike should be ridden. so It's your final decision on how to approach this derailleur mounting problem.

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Old 10-03-10, 05:34 PM   #11
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where did you get the frame from? what happened to the original one?
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Old 10-03-10, 05:42 PM   #12
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I had a PM from a poster and I'm unable to respond since my post count is under 50. I guess I'll just publicly reply here and hopefully he get's it.

I just took a measurement with my cheapo caliper and it looks like its about 10mm (give or take a mm) from the center of the bottom rivnut to the center of the top rivnut. If it looks like the part you have will fit I would gladly reimburse you for the part and shipping! Thank you so much! PM me your email address so that I can get back to you.
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Old 10-03-10, 05:50 PM   #13
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The frame looks to be in great shape structurally, it's pretty scratched up though It's been ridden very hard and shows it, but that just gives it character. There is a balance between correct and working, I completely understand. It's going to be used for triathlons eventually, so I'm not too concerned with making it pristine but I'd rather do the build correctly so eventually it could be made period correct.
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Old 10-03-10, 05:59 PM   #14
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I bought the frame and fork for 100 bucks off of a guy in Kansas City, MO. It was an interesting trip, found the bike via Craigslist and met up with the guy at an old building. He's brought me inside and took me to a sketchy elevator where we ended up on a floor full of bikes and bike parts. He said he's been wrenching on and collecting bikes for years and he certainly had the collection to show for it. According to this guy, the bike was once raced professionally but I can't remember who he said rode the bike. Might have just been a story to make the bike sound impressive Unfortunately, the frame had pretty much everything missing, so I've been trying to track this stuff down. I found the bottom bracket cable guide two weeks ago and hopefully the FD hanger soon!

I've been riding the bike as a single speed for the past two years and just love the fit of the bike. Sure it's a bit of a jackhammer but it's not terrible.
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Old 10-03-10, 07:50 PM   #15
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You have a front derailler made for braze-on tabs. Shimano also makes front deraillers that clamp on to the seat tube. If you don't have the braze-on tab already on your frame, then I would just get a clamp-on style front derailler.
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Old 10-03-10, 08:38 PM   #16
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You have a front derailler made for braze-on tabs. Shimano also makes front deraillers that clamp on to the seat tube. If you don't have the braze-on tab already on your frame, then I would just get a clamp-on style front derailler.
Yup, that's what I'm debating currently. I've tried fitting the correct size clamp on but it doesn't fit around the rivnuts so in order to use a clamp style I would have to drill out the rivnuts. I was messaged by a poster on the forum saying that he might have the correct tab/hanger so hopefully I can go the correct route and use that.
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Old 10-22-10, 07:08 PM   #17
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After doing a google image search, this is the thing that I need



Does anyone know what it's called?
This is EXACTLY what I need, but no matter what kind of search I do via Google, all I find are clamp-on adapters.
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Old 10-22-10, 08:03 PM   #18
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I have a Trek 1200 and it is missing the same bracket and I got a clamp-on derailleur adapter to work. Instead of drilling out the rivnuts, maybe just file slots in the clamp-on bracket to fit over them.
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Old 10-22-10, 10:30 PM   #19
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This is EXACTLY what I need, but no matter what kind of search I do via Google, all I find are clamp-on adapters.
I ended up having to order it from Cannondale, it was 12 dollars so not bad. The one the forum member sent me was angled incorrectly unfortunately. Is yours a cannondale? Could you measure the center to center distance on your rivnuts? If its about 15mm I'll mail the extra one I have to you and see if it works.
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Old 10-23-10, 07:29 AM   #20
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I'm in the same predicament and also ordered one from Cannondale, so we shall see if it's the correct part. I work on a bunch of these frames, and all of the ones I've seen in the past are the same size and dimension.

Alternatively, you can take a 34.9 clamping FD and get shims to bring the clamp down to 31.8, then remove any part of the shim that interferes with the rivnut when the clamp is in the right place for your component setup. That way you get a nice, tight fit without drilling out the rivnuts.
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Old 10-25-10, 10:26 AM   #21
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I ended up having to order it from Cannondale, it was 12 dollars so not bad. The one the forum member sent me was angled incorrectly unfortunately. Is yours a cannondale? Could you measure the center to center distance on your rivnuts? If its about 15mm I'll mail the extra one I have to you and see if it works.
c-c measurement comes out to around 15mm =) Go ahead and PM me about sending out that extra mount -- I would be extremely happy!
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Old 10-25-10, 09:05 PM   #22
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c-c measurement comes out to around 15mm =) Go ahead and PM me about sending out that extra mount -- I would be extremely happy!
Sounds good, PM'd
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