8 speed on 126 mm frame question
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8 speed on 126 mm frame question
I'm in the process of rehabbing a previously unloved Merckx Century frame ('89 Reynolds 653). It is 126 mm spaced. I recently picked up a nice set of 8 speed Record DT shifters and because I'm an idiot I thought it would be fun to build up a bike around these.
I searched BF for threads on this but came up empty, so I'll just try it anyway. I'm not planning on cold setting the frame. I've heard that can be problematic with Reynolds 753 , which is what this rear triangle is supposed to be. If it doesn't work well I have a 7 speed wheel set in reserve.
I welcome any comments and insight on this but my specific question is in regards to the wheel spacers. I will use a Chorus free hub, 130 mm spacing of course. There are spacers on the NDS, a 2 mm (silver colored) and a 1 mm. Pic below. If I took one or both of these off, do you think it would help? Less spread on the rear stays, maybe better shifting? In the current set up it looks like there's a mm or 2 on either side from the outside of the dropout and end of the axle. I suppose it would be problematic if the axle ends up flush with the dropout.
I'm always willing to just try but this would involve a re-dish of the wheel, so kind of a hassle. Also could use an oil port cover if anyone has an extra laying around!
I searched BF for threads on this but came up empty, so I'll just try it anyway. I'm not planning on cold setting the frame. I've heard that can be problematic with Reynolds 753 , which is what this rear triangle is supposed to be. If it doesn't work well I have a 7 speed wheel set in reserve.
I welcome any comments and insight on this but my specific question is in regards to the wheel spacers. I will use a Chorus free hub, 130 mm spacing of course. There are spacers on the NDS, a 2 mm (silver colored) and a 1 mm. Pic below. If I took one or both of these off, do you think it would help? Less spread on the rear stays, maybe better shifting? In the current set up it looks like there's a mm or 2 on either side from the outside of the dropout and end of the axle. I suppose it would be problematic if the axle ends up flush with the dropout.
I'm always willing to just try but this would involve a re-dish of the wheel, so kind of a hassle. Also could use an oil port cover if anyone has an extra laying around!
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Have you actually measured the dropout width? That late a lot of manufacturers were doing 128 dropouts and would fit both.
If the wheel is in good shape with good nipples the redish is pretty easy if you go with the spacers.
If the wheel is in good shape with good nipples the redish is pretty easy if you go with the spacers.
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I have. The EM is 126 measured and the wheel fits snugly in a 130 mm frame. In '89 I'm pretty sure 7 speed was still the standard and 8 came along a couple of years later.
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My understanding is that Reynolds 753 has similar flexibility to any other steel (in terms of being able to spread the dropouts enough to get a 130mm wheel in there) and that it's just its higher yield strength that makes it harder to cold set -- that is, it takes more stretching to get it to stay open. As such, I think it would be just as good of a candidate (and arguably better) for squeezing a wheel in there without cold setting as any other frame.
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A few options here... you can get a Tiagra hub, respace it for 126mm and rebuild a wheel. I've done this. You can also get a 7-speed freehub body for it, which gives you another ~2mm of offset. I've done this, too. You can also use 8-speed shifters with a 7-speed cassette, the cog center-to-center difference is only 0.2mm, definitely usable.
If you actually want all 8 gears, then new rear hub/wheel is the only way to go, obviously. I wouldn't recommend an 8-speed freewheel.
(EDIT)
If you want to keep using the original Chorus hub there (which is very nice) you should be able to remove the NDS spacers. I don't know if there's a shorter cassette body you can get for it. 3mm removed should be enough to get it in there, you might be able to get thinner locknuts too. 127mm would work.
If you actually want all 8 gears, then new rear hub/wheel is the only way to go, obviously. I wouldn't recommend an 8-speed freewheel.
(EDIT)
If you want to keep using the original Chorus hub there (which is very nice) you should be able to remove the NDS spacers. I don't know if there's a shorter cassette body you can get for it. 3mm removed should be enough to get it in there, you might be able to get thinner locknuts too. 127mm would work.
Last edited by FunkyStickman; 08-17-16 at 12:31 PM. Reason: Cause I'm dumb
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You can also use a 7 speed freehub and a 9 speed cassette with the smallest cog removed. You'll have an 8 speed 126 mm wheel with less dish that way, but you won't be able to use an 8 speed indexed shifter.
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You should be able to spread 126mm to 130mm without cold setting - that's 2mm each side.
Worked perfectly on my daughter's Team Fuji.
If you get it too narrow with 8 gears you may have a chain suck problem on the seat stay
753 is just alloyed for TiG welding
Worked perfectly on my daughter's Team Fuji.
If you get it too narrow with 8 gears you may have a chain suck problem on the seat stay
753 is just alloyed for TiG welding
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Thanks all!
I can get the wheel in without too much problem. Also I'm not too worried about spreading the frame but I wasn't sure if the spread would cause shifting problems (misaligned hangers and dropouts) so thought shaving a couple of mm off the spread might help out with that.
I can get the wheel in without too much problem. Also I'm not too worried about spreading the frame but I wasn't sure if the spread would cause shifting problems (misaligned hangers and dropouts) so thought shaving a couple of mm off the spread might help out with that.
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The problem with stretching without cold setting is that the dropouts won't be parallel, which will result in a bending force to the axle, which can often result in broken axles and damaged bearings/races/cones.
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most people agree you don't need cold-setting 126mm to 130
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I'm in the (slow) process of building up a 753 frame. I was originally thinking of building with 10speed, but decided against based on a bunch of reading I don't have at my fingertips currently. The previous owner had the bike built with 10sp for a while and it worked fine for him, I'm sticking with 126 to err on the side of caution (measures closer to 125/124mm). 753 cannot be coldset (will buckle first according to some who built with it). While you're only spreading 2mm per side, it does build stresses into the rear triangle (apart from possible alignment issues). Not only are you spreading the dropouts to fit the wheel, in the process the dropouts diverge from parallel. As the QR skewer is tightened this will attempt to bring the DO faces back to parallel through contact with the axle lock nuts. This builds additional stresses into the dropouts/rear triangle. This might be fudged/mitigated to an extent with effort. Spreading 753 may be fine over the long haul, it's a matter of how comfortable you are with "maybe". Also consider other loads from rider weight and terrain, etc. as 'normal' riding loads and resulting stresses will be superimposed on top of any 'built in' stresses. 'Normal' steel is fine to spread, 753 is a slightly different animal. It is heat treated and has a higher hardness value with thinner tube walls. If I'm remembering correctly.
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I agree with this. I have two Cannondales with 126 mm DOs that are running with 130 OLD hubs, one of them for about the last 20 years. As long as there isn't an existing problem you should be good to go.
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If the stays aren't dimpled, it's pretty much that easy, just sneak up on it. Ed's arms are well calibrated.
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My understanding is that Reynolds 753 has similar flexibility to any other steel (in terms of being able to spread the dropouts enough to get a 130mm wheel in there) and that it's just its higher yield strength that makes it harder to cold set -- that is, it takes more stretching to get it to stay open. As such, I think it would be just as good of a candidate (and arguably better) for squeezing a wheel in there without cold setting as any other frame.
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